diff --git a/Documentation/x86/pat.txt b/Documentation/x86/pat.txt
index 54944c7..2a4ee63 100644
--- a/Documentation/x86/pat.txt
+++ b/Documentation/x86/pat.txt
@@ -196,3 +196,35 @@
 "debugpat" boot parameter. With this parameter, various debug messages are
 printed to dmesg log.
 
+PAT Initialization
+------------------
+
+The following table describes how PAT is initialized under various
+configurations. The PAT MSR must be updated by Linux in order to support WC
+and WT attributes. Otherwise, the PAT MSR has the value programmed in it
+by the firmware. Note, Xen enables WC attribute in the PAT MSR for guests.
+
+ MTRR PAT   Call Sequence               PAT State  PAT MSR
+ =========================================================
+ E    E     MTRR -> PAT init            Enabled    OS
+ E    D     MTRR -> PAT init            Disabled    -
+ D    E     MTRR -> PAT disable         Disabled   BIOS
+ D    D     MTRR -> PAT disable         Disabled    -
+ -    np/E  PAT  -> PAT disable         Disabled   BIOS
+ -    np/D  PAT  -> PAT disable         Disabled    -
+ E    !P/E  MTRR -> PAT init            Disabled   BIOS
+ D    !P/E  MTRR -> PAT disable         Disabled   BIOS
+ !M   !P/E  MTRR stub -> PAT disable    Disabled   BIOS
+
+ Legend
+ ------------------------------------------------
+ E         Feature enabled in CPU
+ D	   Feature disabled/unsupported in CPU
+ np	   "nopat" boot option specified
+ !P	   CONFIG_X86_PAT option unset
+ !M	   CONFIG_MTRR option unset
+ Enabled   PAT state set to enabled
+ Disabled  PAT state set to disabled
+ OS        PAT initializes PAT MSR with OS setting
+ BIOS      PAT keeps PAT MSR with BIOS setting
+
diff --git a/arch/ia64/include/asm/iommu.h b/arch/ia64/include/asm/iommu.h
index 105c93b..1d12129 100644
--- a/arch/ia64/include/asm/iommu.h
+++ b/arch/ia64/include/asm/iommu.h
@@ -1,7 +1,6 @@
 #ifndef _ASM_IA64_IOMMU_H
 #define _ASM_IA64_IOMMU_H 1
 
-#define cpu_has_x2apic 0
 /* 10 seconds */
 #define DMAR_OPERATION_TIMEOUT (((cycles_t) local_cpu_data->itc_freq)*10)
 
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 064c7e2..5b7fa14 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -1477,7 +1477,7 @@
 	}
 	aesni_ctr_enc_tfm = aesni_ctr_enc;
 #ifdef CONFIG_AS_AVX
-	if (cpu_has_avx) {
+	if (boot_cpu_has(X86_FEATURE_AVX)) {
 		/* optimize performance of ctr mode encryption transform */
 		aesni_ctr_enc_tfm = aesni_ctr_enc_avx_tfm;
 		pr_info("AES CTR mode by8 optimization enabled\n");
diff --git a/arch/x86/crypto/camellia_aesni_avx2_glue.c b/arch/x86/crypto/camellia_aesni_avx2_glue.c
index d844569..60907c1 100644
--- a/arch/x86/crypto/camellia_aesni_avx2_glue.c
+++ b/arch/x86/crypto/camellia_aesni_avx2_glue.c
@@ -562,7 +562,10 @@
 {
 	const char *feature_name;
 
-	if (!cpu_has_avx2 || !cpu_has_avx || !cpu_has_aes || !cpu_has_osxsave) {
+	if (!boot_cpu_has(X86_FEATURE_AVX) ||
+	    !boot_cpu_has(X86_FEATURE_AVX2) ||
+	    !boot_cpu_has(X86_FEATURE_AES) ||
+	    !boot_cpu_has(X86_FEATURE_OSXSAVE)) {
 		pr_info("AVX2 or AES-NI instructions are not detected.\n");
 		return -ENODEV;
 	}
diff --git a/arch/x86/crypto/camellia_aesni_avx_glue.c b/arch/x86/crypto/camellia_aesni_avx_glue.c
index 93d8f29..d96429d 100644
--- a/arch/x86/crypto/camellia_aesni_avx_glue.c
+++ b/arch/x86/crypto/camellia_aesni_avx_glue.c
@@ -554,7 +554,9 @@
 {
 	const char *feature_name;
 
-	if (!cpu_has_avx || !cpu_has_aes || !cpu_has_osxsave) {
+	if (!boot_cpu_has(X86_FEATURE_AVX) ||
+	    !boot_cpu_has(X86_FEATURE_AES) ||
+	    !boot_cpu_has(X86_FEATURE_OSXSAVE)) {
 		pr_info("AVX or AES-NI instructions are not detected.\n");
 		return -ENODEV;
 	}
diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c
index 8baaff5..2d5c2e0b 100644
--- a/arch/x86/crypto/chacha20_glue.c
+++ b/arch/x86/crypto/chacha20_glue.c
@@ -129,7 +129,8 @@
 		return -ENODEV;
 
 #ifdef CONFIG_AS_AVX2
-	chacha20_use_avx2 = cpu_has_avx && cpu_has_avx2 &&
+	chacha20_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
+			    boot_cpu_has(X86_FEATURE_AVX2) &&
 			    cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
 #endif
 	return crypto_register_alg(&alg);
diff --git a/arch/x86/crypto/poly1305_glue.c b/arch/x86/crypto/poly1305_glue.c
index 4264a3d..e32142b 100644
--- a/arch/x86/crypto/poly1305_glue.c
+++ b/arch/x86/crypto/poly1305_glue.c
@@ -179,11 +179,12 @@
 
 static int __init poly1305_simd_mod_init(void)
 {
-	if (!cpu_has_xmm2)
+	if (!boot_cpu_has(X86_FEATURE_XMM2))
 		return -ENODEV;
 
 #ifdef CONFIG_AS_AVX2
-	poly1305_use_avx2 = cpu_has_avx && cpu_has_avx2 &&
+	poly1305_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
+			    boot_cpu_has(X86_FEATURE_AVX2) &&
 			    cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
 	alg.descsize = sizeof(struct poly1305_simd_desc_ctx);
 	if (poly1305_use_avx2)
diff --git a/arch/x86/crypto/serpent_avx2_glue.c b/arch/x86/crypto/serpent_avx2_glue.c
index 6d19834..870f6d8 100644
--- a/arch/x86/crypto/serpent_avx2_glue.c
+++ b/arch/x86/crypto/serpent_avx2_glue.c
@@ -538,7 +538,7 @@
 {
 	const char *feature_name;
 
-	if (!cpu_has_avx2 || !cpu_has_osxsave) {
+	if (!boot_cpu_has(X86_FEATURE_AVX2) || !boot_cpu_has(X86_FEATURE_OSXSAVE)) {
 		pr_info("AVX2 instructions are not detected.\n");
 		return -ENODEV;
 	}
diff --git a/arch/x86/crypto/serpent_sse2_glue.c b/arch/x86/crypto/serpent_sse2_glue.c
index 8943407..644f97a 100644
--- a/arch/x86/crypto/serpent_sse2_glue.c
+++ b/arch/x86/crypto/serpent_sse2_glue.c
@@ -600,7 +600,7 @@
 
 static int __init serpent_sse2_init(void)
 {
-	if (!cpu_has_xmm2) {
+	if (!boot_cpu_has(X86_FEATURE_XMM2)) {
 		printk(KERN_INFO "SSE2 instructions are not detected.\n");
 		return -ENODEV;
 	}
diff --git a/arch/x86/crypto/sha1_ssse3_glue.c b/arch/x86/crypto/sha1_ssse3_glue.c
index dd14616..1024e37 100644
--- a/arch/x86/crypto/sha1_ssse3_glue.c
+++ b/arch/x86/crypto/sha1_ssse3_glue.c
@@ -166,7 +166,7 @@
 static bool avx_usable(void)
 {
 	if (!cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
-		if (cpu_has_avx)
+		if (boot_cpu_has(X86_FEATURE_AVX))
 			pr_info("AVX detected but unusable.\n");
 		return false;
 	}
diff --git a/arch/x86/crypto/sha256_ssse3_glue.c b/arch/x86/crypto/sha256_ssse3_glue.c
index 5f4d608..3ae0f43 100644
--- a/arch/x86/crypto/sha256_ssse3_glue.c
+++ b/arch/x86/crypto/sha256_ssse3_glue.c
@@ -201,7 +201,7 @@
 static bool avx_usable(void)
 {
 	if (!cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
-		if (cpu_has_avx)
+		if (boot_cpu_has(X86_FEATURE_AVX))
 			pr_info("AVX detected but unusable.\n");
 		return false;
 	}
diff --git a/arch/x86/crypto/sha512_ssse3_glue.c b/arch/x86/crypto/sha512_ssse3_glue.c
index 34e5083..0b17c83 100644
--- a/arch/x86/crypto/sha512_ssse3_glue.c
+++ b/arch/x86/crypto/sha512_ssse3_glue.c
@@ -151,7 +151,7 @@
 static bool avx_usable(void)
 {
 	if (!cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {
-		if (cpu_has_avx)
+		if (boot_cpu_has(X86_FEATURE_AVX))
 			pr_info("AVX detected but unusable.\n");
 		return false;
 	}
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 858b555..1693c17 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -781,15 +781,15 @@
 	pushfq
 	DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI)
 	SWAPGS
-gs_change:
+.Lgs_change:
 	movl	%edi, %gs
-2:	mfence					/* workaround */
+2:	ALTERNATIVE "", "mfence", X86_BUG_SWAPGS_FENCE
 	SWAPGS
 	popfq
 	ret
 END(native_load_gs_index)
 
-	_ASM_EXTABLE(gs_change, bad_gs)
+	_ASM_EXTABLE(.Lgs_change, bad_gs)
 	.section .fixup, "ax"
 	/* running with kernelgs */
 bad_gs:
@@ -1019,13 +1019,13 @@
 	movl	%ecx, %eax			/* zero extend */
 	cmpq	%rax, RIP+8(%rsp)
 	je	.Lbstep_iret
-	cmpq	$gs_change, RIP+8(%rsp)
+	cmpq	$.Lgs_change, RIP+8(%rsp)
 	jne	.Lerror_entry_done
 
 	/*
-	 * hack: gs_change can fail with user gsbase.  If this happens, fix up
+	 * hack: .Lgs_change can fail with user gsbase.  If this happens, fix up
 	 * gsbase and proceed.  We'll fix up the exception and land in
-	 * gs_change's error handler with kernel gsbase.
+	 * .Lgs_change's error handler with kernel gsbase.
 	 */
 	jmp	.Lerror_entry_from_usermode_swapgs
 
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index b30dd81..4cddd17 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -384,5 +384,5 @@
 375	i386	membarrier		sys_membarrier
 376	i386	mlock2			sys_mlock2
 377	i386	copy_file_range		sys_copy_file_range
-378	i386	preadv2			sys_preadv2
-379	i386	pwritev2		sys_pwritev2
+378	i386	preadv2			sys_preadv2			compat_sys_preadv2
+379	i386	pwritev2		sys_pwritev2			compat_sys_pwritev2
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index cac6d17..555263e 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -374,3 +374,5 @@
 543	x32	io_setup		compat_sys_io_setup
 544	x32	io_submit		compat_sys_io_submit
 545	x32	execveat		compat_sys_execveat/ptregs
+534	x32	preadv2			compat_sys_preadv2
+535	x32	pwritev2		compat_sys_pwritev2
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c
index 03c3eb7..2f02d23 100644
--- a/arch/x86/entry/vdso/vclock_gettime.c
+++ b/arch/x86/entry/vdso/vclock_gettime.c
@@ -13,7 +13,6 @@
 
 #include <uapi/linux/time.h>
 #include <asm/vgtod.h>
-#include <asm/hpet.h>
 #include <asm/vvar.h>
 #include <asm/unistd.h>
 #include <asm/msr.h>
@@ -28,16 +27,6 @@
 extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
 extern time_t __vdso_time(time_t *t);
 
-#ifdef CONFIG_HPET_TIMER
-extern u8 hpet_page
-	__attribute__((visibility("hidden")));
-
-static notrace cycle_t vread_hpet(void)
-{
-	return *(const volatile u32 *)(&hpet_page + HPET_COUNTER);
-}
-#endif
-
 #ifdef CONFIG_PARAVIRT_CLOCK
 extern u8 pvclock_page
 	__attribute__((visibility("hidden")));
@@ -195,10 +184,6 @@
 
 	if (gtod->vclock_mode == VCLOCK_TSC)
 		cycles = vread_tsc();
-#ifdef CONFIG_HPET_TIMER
-	else if (gtod->vclock_mode == VCLOCK_HPET)
-		cycles = vread_hpet();
-#endif
 #ifdef CONFIG_PARAVIRT_CLOCK
 	else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
 		cycles = vread_pvclock(mode);
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index 4158acc..a708aa9 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -25,7 +25,7 @@
 	 * segment.
 	 */
 
-	vvar_start = . - 3 * PAGE_SIZE;
+	vvar_start = . - 2 * PAGE_SIZE;
 	vvar_page = vvar_start;
 
 	/* Place all vvars at the offsets in asm/vvar.h. */
@@ -35,8 +35,7 @@
 #undef __VVAR_KERNEL_LDS
 #undef EMIT_VVAR
 
-	hpet_page = vvar_start + PAGE_SIZE;
-	pvclock_page = vvar_start + 2 * PAGE_SIZE;
+	pvclock_page = vvar_start + PAGE_SIZE;
 
 	. = SIZEOF_HEADERS;
 
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 10f7045..b3cf813 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -18,7 +18,6 @@
 #include <asm/vdso.h>
 #include <asm/vvar.h>
 #include <asm/page.h>
-#include <asm/hpet.h>
 #include <asm/desc.h>
 #include <asm/cpufeature.h>
 
@@ -129,16 +128,6 @@
 	if (sym_offset == image->sym_vvar_page) {
 		ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address,
 				    __pa_symbol(&__vvar_page) >> PAGE_SHIFT);
-	} else if (sym_offset == image->sym_hpet_page) {
-#ifdef CONFIG_HPET_TIMER
-		if (hpet_address && vclock_was_used(VCLOCK_HPET)) {
-			ret = vm_insert_pfn_prot(
-				vma,
-				(unsigned long)vmf->virtual_address,
-				hpet_address >> PAGE_SHIFT,
-				pgprot_noncached(PAGE_READONLY));
-		}
-#endif
 	} else if (sym_offset == image->sym_pvclock_page) {
 		struct pvclock_vsyscall_time_info *pvti =
 			pvclock_pvti_cpu0_va();
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 041e442..54c1745 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -1518,7 +1518,7 @@
 
 static void __init pmu_check_apic(void)
 {
-	if (cpu_has_apic)
+	if (boot_cpu_has(X86_FEATURE_APIC))
 		return;
 
 	x86_pmu.apic = 0;
diff --git a/arch/x86/events/intel/cstate.c b/arch/x86/events/intel/cstate.c
index 7946c42..d5045c8 100644
--- a/arch/x86/events/intel/cstate.c
+++ b/arch/x86/events/intel/cstate.c
@@ -677,7 +677,7 @@
 {
 	int err;
 
-	if (cpu_has_hypervisor)
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return -ENODEV;
 
 	err = cstate_init();
diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 7012d18..3f6d8b5 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1383,7 +1383,7 @@
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 		return -ENODEV;
 
-	if (cpu_has_hypervisor)
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return -ENODEV;
 
 	max_packages = topology_max_packages();
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 0552884..2f29f4e 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -357,7 +357,7 @@
 		put_user_ex(ptr_to_compat(&frame->uc), &frame->puc);
 
 		/* Create the ucontext.  */
-		if (cpu_has_xsave)
+		if (boot_cpu_has(X86_FEATURE_XSAVE))
 			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 		else
 			put_user_ex(0, &frame->uc.uc_flags);
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 98f25bb..bc27611 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -239,10 +239,10 @@
 extern void x2apic_setup(void);
 static inline int x2apic_enabled(void)
 {
-	return cpu_has_x2apic && apic_is_x2apic_enabled();
+	return boot_cpu_has(X86_FEATURE_X2APIC) && apic_is_x2apic_enabled();
 }
 
-#define x2apic_supported()	(cpu_has_x2apic)
+#define x2apic_supported()	(boot_cpu_has(X86_FEATURE_X2APIC))
 #else /* !CONFIG_X86_X2APIC */
 static inline void check_x2apic(void) { }
 static inline void x2apic_setup(void) { }
diff --git a/arch/x86/include/asm/clocksource.h b/arch/x86/include/asm/clocksource.h
index d194266..eae33c7 100644
--- a/arch/x86/include/asm/clocksource.h
+++ b/arch/x86/include/asm/clocksource.h
@@ -3,11 +3,10 @@
 #ifndef _ASM_X86_CLOCKSOURCE_H
 #define _ASM_X86_CLOCKSOURCE_H
 
-#define VCLOCK_NONE	0  /* No vDSO clock available.	*/
-#define VCLOCK_TSC	1  /* vDSO should use vread_tsc.	*/
-#define VCLOCK_HPET	2  /* vDSO should use vread_hpet.	*/
-#define VCLOCK_PVCLOCK	3 /* vDSO should use vread_pvclock. */
-#define VCLOCK_MAX	3
+#define VCLOCK_NONE	0	/* No vDSO clock available.		*/
+#define VCLOCK_TSC	1	/* vDSO should use vread_tsc.		*/
+#define VCLOCK_PVCLOCK	2	/* vDSO should use vread_pvclock.	*/
+#define VCLOCK_MAX	2
 
 struct arch_clocksource_data {
 	int vclock_mode;
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 3636ec0..07c942d 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -118,31 +118,6 @@
 	set_bit(bit, (unsigned long *)cpu_caps_set);	\
 } while (0)
 
-#define cpu_has_fpu		boot_cpu_has(X86_FEATURE_FPU)
-#define cpu_has_pse		boot_cpu_has(X86_FEATURE_PSE)
-#define cpu_has_tsc		boot_cpu_has(X86_FEATURE_TSC)
-#define cpu_has_pge		boot_cpu_has(X86_FEATURE_PGE)
-#define cpu_has_apic		boot_cpu_has(X86_FEATURE_APIC)
-#define cpu_has_fxsr		boot_cpu_has(X86_FEATURE_FXSR)
-#define cpu_has_xmm		boot_cpu_has(X86_FEATURE_XMM)
-#define cpu_has_xmm2		boot_cpu_has(X86_FEATURE_XMM2)
-#define cpu_has_aes		boot_cpu_has(X86_FEATURE_AES)
-#define cpu_has_avx		boot_cpu_has(X86_FEATURE_AVX)
-#define cpu_has_avx2		boot_cpu_has(X86_FEATURE_AVX2)
-#define cpu_has_clflush		boot_cpu_has(X86_FEATURE_CLFLUSH)
-#define cpu_has_gbpages		boot_cpu_has(X86_FEATURE_GBPAGES)
-#define cpu_has_arch_perfmon	boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
-#define cpu_has_pat		boot_cpu_has(X86_FEATURE_PAT)
-#define cpu_has_x2apic		boot_cpu_has(X86_FEATURE_X2APIC)
-#define cpu_has_xsave		boot_cpu_has(X86_FEATURE_XSAVE)
-#define cpu_has_xsaves		boot_cpu_has(X86_FEATURE_XSAVES)
-#define cpu_has_osxsave		boot_cpu_has(X86_FEATURE_OSXSAVE)
-#define cpu_has_hypervisor	boot_cpu_has(X86_FEATURE_HYPERVISOR)
-/*
- * Do not add any more of those clumsy macros - use static_cpu_has() for
- * fast paths and boot_cpu_has() otherwise!
- */
-
 #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_X86_FAST_FEATURE_TESTS)
 /*
  * Static testing of CPU features.  Used the same as boot_cpu_has().
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 8f9afef..7bfb6b7 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -294,6 +294,9 @@
 #define X86_BUG_FXSAVE_LEAK	X86_BUG(6) /* FXSAVE leaks FOP/FIP/FOP */
 #define X86_BUG_CLFLUSH_MONITOR	X86_BUG(7) /* AAI65, CLFLUSH required before MONITOR */
 #define X86_BUG_SYSRET_SS_ATTRS	X86_BUG(8) /* SYSRET doesn't fix up SS attrs */
+#define X86_BUG_NULL_SEG	X86_BUG(9) /* Nulling a selector preserves the base */
+#define X86_BUG_SWAPGS_FENCE	X86_BUG(10) /* SWAPGS without input dep on GS */
+
 
 #ifdef CONFIG_X86_32
 /*
diff --git a/arch/x86/include/asm/irq_work.h b/arch/x86/include/asm/irq_work.h
index d0afb05..f706041 100644
--- a/arch/x86/include/asm/irq_work.h
+++ b/arch/x86/include/asm/irq_work.h
@@ -5,7 +5,7 @@
 
 static inline bool arch_irq_work_has_interrupt(void)
 {
-	return cpu_has_apic;
+	return boot_cpu_has(X86_FEATURE_APIC);
 }
 
 #endif /* _ASM_IRQ_WORK_H */
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 7a79ee2..7dc1d8f 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -84,7 +84,10 @@
 {
 	DECLARE_ARGS(val, low, high);
 
-	asm volatile("rdmsr" : EAX_EDX_RET(val, low, high) : "c" (msr));
+	asm volatile("1: rdmsr\n"
+		     "2:\n"
+		     _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_rdmsr_unsafe)
+		     : EAX_EDX_RET(val, low, high) : "c" (msr));
 	if (msr_tracepoint_active(__tracepoint_read_msr))
 		do_trace_read_msr(msr, EAX_EDX_VAL(val, low, high), 0);
 	return EAX_EDX_VAL(val, low, high);
@@ -98,7 +101,10 @@
 	asm volatile("2: rdmsr ; xor %[err],%[err]\n"
 		     "1:\n\t"
 		     ".section .fixup,\"ax\"\n\t"
-		     "3:  mov %[fault],%[err] ; jmp 1b\n\t"
+		     "3: mov %[fault],%[err]\n\t"
+		     "xorl %%eax, %%eax\n\t"
+		     "xorl %%edx, %%edx\n\t"
+		     "jmp 1b\n\t"
 		     ".previous\n\t"
 		     _ASM_EXTABLE(2b, 3b)
 		     : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
@@ -108,10 +114,14 @@
 	return EAX_EDX_VAL(val, low, high);
 }
 
-static inline void native_write_msr(unsigned int msr,
-				    unsigned low, unsigned high)
+/* Can be uninlined because referenced by paravirt */
+notrace static inline void native_write_msr(unsigned int msr,
+					    unsigned low, unsigned high)
 {
-	asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high) : "memory");
+	asm volatile("1: wrmsr\n"
+		     "2:\n"
+		     _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_wrmsr_unsafe)
+		     : : "c" (msr), "a"(low), "d" (high) : "memory");
 	if (msr_tracepoint_active(__tracepoint_read_msr))
 		do_trace_write_msr(msr, ((u64)high << 32 | low), 0);
 }
diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
index b94f6f6..dbff145 100644
--- a/arch/x86/include/asm/mtrr.h
+++ b/arch/x86/include/asm/mtrr.h
@@ -24,6 +24,7 @@
 #define _ASM_X86_MTRR_H
 
 #include <uapi/asm/mtrr.h>
+#include <asm/pat.h>
 
 
 /*
@@ -83,9 +84,12 @@
 static inline void mtrr_centaur_report_mcr(int mcr, u32 lo, u32 hi)
 {
 }
+static inline void mtrr_bp_init(void)
+{
+	pat_disable("MTRRs disabled, skipping PAT initialization too.");
+}
 
 #define mtrr_ap_init() do {} while (0)
-#define mtrr_bp_init() do {} while (0)
 #define set_mtrr_aps_delayed_init() do {} while (0)
 #define mtrr_aps_init() do {} while (0)
 #define mtrr_bp_restore() do {} while (0)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 601f1b8..3c73141 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -130,21 +130,31 @@
 
 #define get_kernel_rpl()  (pv_info.kernel_rpl)
 
-static inline u64 paravirt_read_msr(unsigned msr, int *err)
+static inline u64 paravirt_read_msr(unsigned msr)
 {
-	return PVOP_CALL2(u64, pv_cpu_ops.read_msr, msr, err);
+	return PVOP_CALL1(u64, pv_cpu_ops.read_msr, msr);
 }
 
-static inline int paravirt_write_msr(unsigned msr, unsigned low, unsigned high)
+static inline void paravirt_write_msr(unsigned msr,
+				      unsigned low, unsigned high)
 {
-	return PVOP_CALL3(int, pv_cpu_ops.write_msr, msr, low, high);
+	return PVOP_VCALL3(pv_cpu_ops.write_msr, msr, low, high);
 }
 
-/* These should all do BUG_ON(_err), but our headers are too tangled. */
+static inline u64 paravirt_read_msr_safe(unsigned msr, int *err)
+{
+	return PVOP_CALL2(u64, pv_cpu_ops.read_msr_safe, msr, err);
+}
+
+static inline int paravirt_write_msr_safe(unsigned msr,
+					  unsigned low, unsigned high)
+{
+	return PVOP_CALL3(int, pv_cpu_ops.write_msr_safe, msr, low, high);
+}
+
 #define rdmsr(msr, val1, val2)			\
 do {						\
-	int _err;				\
-	u64 _l = paravirt_read_msr(msr, &_err);	\
+	u64 _l = paravirt_read_msr(msr);	\
 	val1 = (u32)_l;				\
 	val2 = _l >> 32;			\
 } while (0)
@@ -156,8 +166,7 @@
 
 #define rdmsrl(msr, val)			\
 do {						\
-	int _err;				\
-	val = paravirt_read_msr(msr, &_err);	\
+	val = paravirt_read_msr(msr);		\
 } while (0)
 
 static inline void wrmsrl(unsigned msr, u64 val)
@@ -165,23 +174,23 @@
 	wrmsr(msr, (u32)val, (u32)(val>>32));
 }
 
-#define wrmsr_safe(msr, a, b)	paravirt_write_msr(msr, a, b)
+#define wrmsr_safe(msr, a, b)	paravirt_write_msr_safe(msr, a, b)
 
 /* rdmsr with exception handling */
-#define rdmsr_safe(msr, a, b)			\
-({						\
-	int _err;				\
-	u64 _l = paravirt_read_msr(msr, &_err);	\
-	(*a) = (u32)_l;				\
-	(*b) = _l >> 32;			\
-	_err;					\
+#define rdmsr_safe(msr, a, b)				\
+({							\
+	int _err;					\
+	u64 _l = paravirt_read_msr_safe(msr, &_err);	\
+	(*a) = (u32)_l;					\
+	(*b) = _l >> 32;				\
+	_err;						\
 })
 
 static inline int rdmsrl_safe(unsigned msr, unsigned long long *p)
 {
 	int err;
 
-	*p = paravirt_read_msr(msr, &err);
+	*p = paravirt_read_msr_safe(msr, &err);
 	return err;
 }
 
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index e8c2326..b4a23ea 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -155,10 +155,16 @@
 	void (*cpuid)(unsigned int *eax, unsigned int *ebx,
 		      unsigned int *ecx, unsigned int *edx);
 
-	/* MSR, PMC and TSR operations.
-	   err = 0/-EFAULT.  wrmsr returns 0/-EFAULT. */
-	u64 (*read_msr)(unsigned int msr, int *err);
-	int (*write_msr)(unsigned int msr, unsigned low, unsigned high);
+	/* Unsafe MSR operations.  These will warn or panic on failure. */
+	u64 (*read_msr)(unsigned int msr);
+	void (*write_msr)(unsigned int msr, unsigned low, unsigned high);
+
+	/*
+	 * Safe MSR operations.
+	 * read sets err to 0 or -EIO.  write returns 0 or -EIO.
+	 */
+	u64 (*read_msr_safe)(unsigned int msr, int *err);
+	int (*write_msr_safe)(unsigned int msr, unsigned low, unsigned high);
 
 	u64 (*read_pmc)(int counter);
 
diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index ca6c228..0b1ff4c 100644
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -5,8 +5,8 @@
 #include <asm/pgtable_types.h>
 
 bool pat_enabled(void);
+void pat_disable(const char *reason);
 extern void pat_init(void);
-void pat_init_cache_modes(u64);
 
 extern int reserve_memtype(u64 start, u64 end,
 		enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 97f3242..f86491a 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -183,7 +183,7 @@
 
 static inline int has_transparent_hugepage(void)
 {
-	return cpu_has_pse;
+	return boot_cpu_has(X86_FEATURE_PSE);
 }
 
 #ifdef __HAVE_ARCH_PTE_DEVMAP
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 1fde8d5..4e5be94 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -181,7 +181,7 @@
 
 static inline void __flush_tlb_all(void)
 {
-	if (cpu_has_pge)
+	if (static_cpu_has(X86_FEATURE_PGE))
 		__flush_tlb_global();
 	else
 		__flush_tlb();
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 174c421..7428697 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -22,7 +22,7 @@
 static inline cycles_t get_cycles(void)
 {
 #ifndef CONFIG_X86_TSC
-	if (!cpu_has_tsc)
+	if (!boot_cpu_has(X86_FEATURE_TSC))
 		return 0;
 #endif
 
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index a969ae6..d794fd1 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -110,7 +110,7 @@
 
 extern int fixup_exception(struct pt_regs *regs, int trapnr);
 extern bool ex_has_fault_handler(unsigned long ip);
-extern int early_fixup_exception(unsigned long *ip);
+extern void early_fixup_exception(struct pt_regs *regs, int trapnr);
 
 /*
  * These are the main single-value transfer routines.  They automatically
diff --git a/arch/x86/include/asm/xor_32.h b/arch/x86/include/asm/xor_32.h
index c54beb4..635eac5 100644
--- a/arch/x86/include/asm/xor_32.h
+++ b/arch/x86/include/asm/xor_32.h
@@ -550,7 +550,7 @@
 #define XOR_TRY_TEMPLATES				\
 do {							\
 	AVX_XOR_SPEED;					\
-	if (cpu_has_xmm) {				\
+	if (boot_cpu_has(X86_FEATURE_XMM)) {				\
 		xor_speed(&xor_block_pIII_sse);		\
 		xor_speed(&xor_block_sse_pf64);		\
 	} else if (boot_cpu_has(X86_FEATURE_MMX)) {	\
diff --git a/arch/x86/include/asm/xor_avx.h b/arch/x86/include/asm/xor_avx.h
index 7c0a517..22a7b18 100644
--- a/arch/x86/include/asm/xor_avx.h
+++ b/arch/x86/include/asm/xor_avx.h
@@ -167,12 +167,12 @@
 
 #define AVX_XOR_SPEED \
 do { \
-	if (cpu_has_avx && cpu_has_osxsave) \
+	if (boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_OSXSAVE)) \
 		xor_speed(&xor_block_avx); \
 } while (0)
 
 #define AVX_SELECT(FASTEST) \
-	(cpu_has_avx && cpu_has_osxsave ? &xor_block_avx : FASTEST)
+	(boot_cpu_has(X86_FEATURE_AVX) && boot_cpu_has(X86_FEATURE_OSXSAVE) ? &xor_block_avx : FASTEST)
 
 #else
 
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 8c2f1ef..2522e56 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -136,7 +136,7 @@
 {
 	struct acpi_table_madt *madt = NULL;
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return -EINVAL;
 
 	madt = (struct acpi_table_madt *)table;
@@ -951,7 +951,7 @@
 {
 	int count;
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return -ENODEV;
 
 	/*
@@ -979,7 +979,7 @@
 	int ret;
 	struct acpi_subtable_proc madt_proc[2];
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return -ENODEV;
 
 	/*
@@ -1125,7 +1125,7 @@
 	if (acpi_disabled || acpi_noirq)
 		return -ENODEV;
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return -ENODEV;
 
 	/*
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index d356987..60078a6 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -607,7 +607,7 @@
 	long tapic = apic_read(APIC_TMCCT);
 	unsigned long pm = acpi_pm_read_early();
 
-	if (cpu_has_tsc)
+	if (boot_cpu_has(X86_FEATURE_TSC))
 		tsc = rdtsc();
 
 	switch (lapic_cal_loops++) {
@@ -668,7 +668,7 @@
 	*delta = (long)res;
 
 	/* Correct the tsc counter value */
-	if (cpu_has_tsc) {
+	if (boot_cpu_has(X86_FEATURE_TSC)) {
 		res = (((u64)(*deltatsc)) * pm_100ms);
 		do_div(res, deltapm);
 		apic_printk(APIC_VERBOSE, "TSC delta adjusted to "
@@ -760,7 +760,7 @@
 	apic_printk(APIC_VERBOSE, "..... calibration result: %u\n",
 		    lapic_timer_frequency);
 
-	if (cpu_has_tsc) {
+	if (boot_cpu_has(X86_FEATURE_TSC)) {
 		apic_printk(APIC_VERBOSE, "..... CPU clock speed is "
 			    "%ld.%04ld MHz.\n",
 			    (deltatsc / LAPIC_CAL_LOOPS) / (1000000 / HZ),
@@ -1085,7 +1085,7 @@
 {
 	unsigned long flags;
 
-	if (!cpu_has_apic && !apic_from_smp_config())
+	if (!boot_cpu_has(X86_FEATURE_APIC) && !apic_from_smp_config())
 		return;
 
 	local_irq_save(flags);
@@ -1134,7 +1134,7 @@
 	 * Don't do the setup now if we have a SMP BIOS as the
 	 * through-I/O-APIC virtual wire mode might be active.
 	 */
-	if (smp_found_config || !cpu_has_apic)
+	if (smp_found_config || !boot_cpu_has(X86_FEATURE_APIC))
 		return;
 
 	/*
@@ -1227,7 +1227,7 @@
 	unsigned long long tsc = 0, ntsc;
 	long long max_loops = cpu_khz ? cpu_khz : 1000000;
 
-	if (cpu_has_tsc)
+	if (boot_cpu_has(X86_FEATURE_TSC))
 		tsc = rdtsc();
 
 	if (disable_apic) {
@@ -1311,7 +1311,7 @@
 			break;
 		}
 		if (queued) {
-			if (cpu_has_tsc && cpu_khz) {
+			if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) {
 				ntsc = rdtsc();
 				max_loops = (cpu_khz << 10) - (ntsc - tsc);
 			} else
@@ -1445,7 +1445,7 @@
 {
 	u64 msr;
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return;
 
 	rdmsrl(MSR_IA32_APICBASE, msr);
@@ -1561,7 +1561,7 @@
 		pr_info("x2apic: enabled by BIOS, switching to x2apic ops\n");
 		x2apic_mode = 1;
 		x2apic_state = X2APIC_ON;
-	} else if (!cpu_has_x2apic) {
+	} else if (!boot_cpu_has(X86_FEATURE_X2APIC)) {
 		x2apic_state = X2APIC_DISABLED;
 	}
 }
@@ -1632,7 +1632,7 @@
  */
 static int __init detect_init_APIC(void)
 {
-	if (!cpu_has_apic) {
+	if (!boot_cpu_has(X86_FEATURE_APIC)) {
 		pr_info("No local APIC present\n");
 		return -1;
 	}
@@ -1711,14 +1711,14 @@
 		goto no_apic;
 	case X86_VENDOR_INTEL:
 		if (boot_cpu_data.x86 == 6 || boot_cpu_data.x86 == 15 ||
-		    (boot_cpu_data.x86 == 5 && cpu_has_apic))
+		    (boot_cpu_data.x86 == 5 && boot_cpu_has(X86_FEATURE_APIC)))
 			break;
 		goto no_apic;
 	default:
 		goto no_apic;
 	}
 
-	if (!cpu_has_apic) {
+	if (!boot_cpu_has(X86_FEATURE_APIC)) {
 		/*
 		 * Over-ride BIOS and try to enable the local APIC only if
 		 * "lapic" specified.
@@ -2233,19 +2233,19 @@
 		return -1;
 	}
 #ifdef CONFIG_X86_64
-	if (!cpu_has_apic) {
+	if (!boot_cpu_has(X86_FEATURE_APIC)) {
 		disable_apic = 1;
 		pr_info("Apic disabled by BIOS\n");
 		return -1;
 	}
 #else
-	if (!smp_found_config && !cpu_has_apic)
+	if (!smp_found_config && !boot_cpu_has(X86_FEATURE_APIC))
 		return -1;
 
 	/*
 	 * Complain if the BIOS pretends there is one.
 	 */
-	if (!cpu_has_apic &&
+	if (!boot_cpu_has(X86_FEATURE_APIC) &&
 	    APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
 		pr_err("BIOS bug, local APIC 0x%x not detected!...\n",
 			boot_cpu_physical_apicid);
@@ -2426,7 +2426,7 @@
 static int __init init_lapic_sysfs(void)
 {
 	/* XXX: remove suspend/resume procs if !apic_pm_state.active? */
-	if (cpu_has_apic)
+	if (boot_cpu_has(X86_FEATURE_APIC))
 		register_syscore_ops(&lapic_syscore_ops);
 
 	return 0;
diff --git a/arch/x86/kernel/apic/apic_noop.c b/arch/x86/kernel/apic/apic_noop.c
index 331a7a0..13d19ed 100644
--- a/arch/x86/kernel/apic/apic_noop.c
+++ b/arch/x86/kernel/apic/apic_noop.c
@@ -100,13 +100,13 @@
 
 static u32 noop_apic_read(u32 reg)
 {
-	WARN_ON_ONCE((cpu_has_apic && !disable_apic));
+	WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
 	return 0;
 }
 
 static void noop_apic_write(u32 reg, u32 v)
 {
-	WARN_ON_ONCE(cpu_has_apic && !disable_apic);
+	WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
 }
 
 struct apic apic_noop = {
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index fdb0fbf..84e33ff 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1454,7 +1454,7 @@
 		ioapic_write_entry(ioapic_i8259.apic, ioapic_i8259.pin, entry);
 	}
 
-	if (cpu_has_apic || apic_from_smp_config())
+	if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
 		disconnect_bsp_APIC(ioapic_i8259.pin != -1);
 }
 
diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index 28bde88..2a0f225 100644
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -230,7 +230,7 @@
 {
 	int apicid, cpuid;
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return 0;
 
 	apicid = hard_smp_processor_id();
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index ad59d70..26d3ccc 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -943,7 +943,7 @@
 	print_PIC();
 
 	/* don't print out if apic is not there */
-	if (!cpu_has_apic && !apic_from_smp_config())
+	if (!boot_cpu_has(X86_FEATURE_APIC) && !apic_from_smp_config())
 		return 0;
 
 	print_local_APICs(show_lapic);
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 7b76eb6..c343a54 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -565,14 +565,17 @@
 	 * can safely set X86_FEATURE_EXTD_APICID unconditionally for families
 	 * after 16h.
 	 */
-	if (cpu_has_apic && c->x86 > 0x16) {
-		set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
-	} else if (cpu_has_apic && c->x86 >= 0xf) {
-		/* check CPU config space for extended APIC ID */
-		unsigned int val;
-		val = read_pci_config(0, 24, 0, 0x68);
-		if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))
+	if (boot_cpu_has(X86_FEATURE_APIC)) {
+		if (c->x86 > 0x16)
 			set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
+		else if (c->x86 >= 0xf) {
+			/* check CPU config space for extended APIC ID */
+			unsigned int val;
+
+			val = read_pci_config(0, 24, 0, 0x68);
+			if ((val >> 17 & 0x3) == 0x3)
+				set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
+		}
 	}
 #endif
 
@@ -628,6 +631,7 @@
 	 */
 	msr_set_bit(MSR_K7_HWCR, 6);
 #endif
+	set_cpu_bug(c, X86_BUG_SWAPGS_FENCE);
 }
 
 static void init_amd_gh(struct cpuinfo_x86 *c)
@@ -746,7 +750,7 @@
 	if (c->x86 >= 0xf)
 		set_cpu_cap(c, X86_FEATURE_K8);
 
-	if (cpu_has_xmm2) {
+	if (cpu_has(c, X86_FEATURE_XMM2)) {
 		/* MFENCE stops RDTSC speculation */
 		set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC);
 	}
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 8394b3d..6bfa36d 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -862,30 +862,34 @@
 #else
 	set_cpu_cap(c, X86_FEATURE_NOPL);
 #endif
+}
 
+static void detect_null_seg_behavior(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_X86_64
 	/*
-	 * ESPFIX is a strange bug.  All real CPUs have it.  Paravirt
-	 * systems that run Linux at CPL > 0 may or may not have the
-	 * issue, but, even if they have the issue, there's absolutely
-	 * nothing we can do about it because we can't use the real IRET
-	 * instruction.
+	 * Empirically, writing zero to a segment selector on AMD does
+	 * not clear the base, whereas writing zero to a segment
+	 * selector on Intel does clear the base.  Intel's behavior
+	 * allows slightly faster context switches in the common case
+	 * where GS is unused by the prev and next threads.
 	 *
-	 * NB: For the time being, only 32-bit kernels support
-	 * X86_BUG_ESPFIX as such.  64-bit kernels directly choose
-	 * whether to apply espfix using paravirt hooks.  If any
-	 * non-paravirt system ever shows up that does *not* have the
-	 * ESPFIX issue, we can change this.
+	 * Since neither vendor documents this anywhere that I can see,
+	 * detect it directly instead of hardcoding the choice by
+	 * vendor.
+	 *
+	 * I've designated AMD's behavior as the "bug" because it's
+	 * counterintuitive and less friendly.
 	 */
-#ifdef CONFIG_X86_32
-#ifdef CONFIG_PARAVIRT
-	do {
-		extern void native_iret(void);
-		if (pv_cpu_ops.iret == native_iret)
-			set_cpu_bug(c, X86_BUG_ESPFIX);
-	} while (0);
-#else
-	set_cpu_bug(c, X86_BUG_ESPFIX);
-#endif
+
+	unsigned long old_base, tmp;
+	rdmsrl(MSR_FS_BASE, old_base);
+	wrmsrl(MSR_FS_BASE, 1);
+	loadsegment(fs, 0);
+	rdmsrl(MSR_FS_BASE, tmp);
+	if (tmp != 0)
+		set_cpu_bug(c, X86_BUG_NULL_SEG);
+	wrmsrl(MSR_FS_BASE, old_base);
 #endif
 }
 
@@ -921,6 +925,33 @@
 	get_model_name(c); /* Default name */
 
 	detect_nopl(c);
+
+	detect_null_seg_behavior(c);
+
+	/*
+	 * ESPFIX is a strange bug.  All real CPUs have it.  Paravirt
+	 * systems that run Linux at CPL > 0 may or may not have the
+	 * issue, but, even if they have the issue, there's absolutely
+	 * nothing we can do about it because we can't use the real IRET
+	 * instruction.
+	 *
+	 * NB: For the time being, only 32-bit kernels support
+	 * X86_BUG_ESPFIX as such.  64-bit kernels directly choose
+	 * whether to apply espfix using paravirt hooks.  If any
+	 * non-paravirt system ever shows up that does *not* have the
+	 * ESPFIX issue, we can change this.
+	 */
+#ifdef CONFIG_X86_32
+# ifdef CONFIG_PARAVIRT
+	do {
+		extern void native_iret(void);
+		if (pv_cpu_ops.iret == native_iret)
+			set_cpu_bug(c, X86_BUG_ESPFIX);
+	} while (0);
+# else
+	set_cpu_bug(c, X86_BUG_ESPFIX);
+# endif
+#endif
 }
 
 static void x86_init_cache_qos(struct cpuinfo_x86 *c)
@@ -1076,12 +1107,12 @@
 	struct tss_struct *tss;
 	int cpu;
 
+	if (!boot_cpu_has(X86_FEATURE_SEP))
+		return;
+
 	cpu = get_cpu();
 	tss = &per_cpu(cpu_tss, cpu);
 
-	if (!boot_cpu_has(X86_FEATURE_SEP))
-		goto out;
-
 	/*
 	 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
 	 * see the big comment in struct x86_hw_tss's definition.
@@ -1096,7 +1127,6 @@
 
 	wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
 
-out:
 	put_cpu();
 }
 #endif
@@ -1528,7 +1558,7 @@
 	pr_info("Initializing CPU#%d\n", cpu);
 
 	if (cpu_feature_enabled(X86_FEATURE_VME) ||
-	    cpu_has_tsc ||
+	    boot_cpu_has(X86_FEATURE_TSC) ||
 	    boot_cpu_has(X86_FEATURE_DE))
 		cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
 
diff --git a/arch/x86/kernel/cpu/cyrix.c b/arch/x86/kernel/cpu/cyrix.c
index 6adef9c..bd9dcd6 100644
--- a/arch/x86/kernel/cpu/cyrix.c
+++ b/arch/x86/kernel/cpu/cyrix.c
@@ -333,7 +333,7 @@
 		switch (dir0_lsn) {
 		case 0xd:  /* either a 486SLC or DLC w/o DEVID */
 			dir0_msn = 0;
-			p = Cx486_name[(cpu_has_fpu ? 1 : 0)];
+			p = Cx486_name[!!boot_cpu_has(X86_FEATURE_FPU)];
 			break;
 
 		case 0xe:  /* a 486S A step */
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1f7fdb9..1d55822 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -152,9 +152,9 @@
 	 *  the TLB when any changes are made to any of the page table entries.
 	 *  The operating system must reload CR3 to cause the TLB to be flushed"
 	 *
-	 * As a result cpu_has_pge() in arch/x86/include/asm/tlbflush.h should
-	 * be false so that __flush_tlb_all() causes CR3 insted of CR4.PGE
-	 * to be modified
+	 * As a result, boot_cpu_has(X86_FEATURE_PGE) in arch/x86/include/asm/tlbflush.h
+	 * should be false so that __flush_tlb_all() causes CR3 insted of CR4.PGE
+	 * to be modified.
 	 */
 	if (c->x86 == 5 && c->x86_model == 9) {
 		pr_info("Disabling PGE capability bit\n");
@@ -281,7 +281,7 @@
 	 * integrated APIC (see 11AP erratum in "Pentium Processor
 	 * Specification Update").
 	 */
-	if (cpu_has_apic && (c->x86<<8 | c->x86_model<<4) == 0x520 &&
+	if (boot_cpu_has(X86_FEATURE_APIC) && (c->x86<<8 | c->x86_model<<4) == 0x520 &&
 	    (c->x86_mask < 0x6 || c->x86_mask == 0xb))
 		set_cpu_bug(c, X86_BUG_11AP);
 
@@ -456,7 +456,7 @@
 			set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
 	}
 
-	if (cpu_has_xmm2)
+	if (cpu_has(c, X86_FEATURE_XMM2))
 		set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
 
 	if (boot_cpu_has(X86_FEATURE_DS)) {
@@ -468,7 +468,7 @@
 			set_cpu_cap(c, X86_FEATURE_PEBS);
 	}
 
-	if (c->x86 == 6 && cpu_has_clflush &&
+	if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_CLFLUSH) &&
 	    (c->x86_model == 29 || c->x86_model == 46 || c->x86_model == 47))
 		set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
 
diff --git a/arch/x86/kernel/cpu/mcheck/mce_intel.c b/arch/x86/kernel/cpu/mcheck/mce_intel.c
index 1e8bb6c..1defb8e 100644
--- a/arch/x86/kernel/cpu/mcheck/mce_intel.c
+++ b/arch/x86/kernel/cpu/mcheck/mce_intel.c
@@ -84,7 +84,7 @@
 	 */
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
 		return 0;
-	if (!cpu_has_apic || lapic_get_maxlvt() < 6)
+	if (!boot_cpu_has(X86_FEATURE_APIC) || lapic_get_maxlvt() < 6)
 		return 0;
 	rdmsrl(MSR_IA32_MCG_CAP, cap);
 	*banks = min_t(unsigned, MAX_NR_BANKS, cap & 0xff);
diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index ac780ca..6b9dc4d 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -450,7 +450,7 @@
 /* Thermal monitoring depends on APIC, ACPI and clock modulation */
 static int intel_thermal_supported(struct cpuinfo_x86 *c)
 {
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return 0;
 	if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
 		return 0;
diff --git a/arch/x86/kernel/cpu/mtrr/cyrix.c b/arch/x86/kernel/cpu/mtrr/cyrix.c
index f8c81ba..b1086f7 100644
--- a/arch/x86/kernel/cpu/mtrr/cyrix.c
+++ b/arch/x86/kernel/cpu/mtrr/cyrix.c
@@ -137,7 +137,7 @@
 	u32 cr0;
 
 	/*  Save value of CR4 and clear Page Global Enable (bit 7)  */
-	if (cpu_has_pge) {
+	if (boot_cpu_has(X86_FEATURE_PGE)) {
 		cr4 = __read_cr4();
 		__write_cr4(cr4 & ~X86_CR4_PGE);
 	}
@@ -170,7 +170,7 @@
 	write_cr0(read_cr0() & ~X86_CR0_CD);
 
 	/* Restore value of CR4 */
-	if (cpu_has_pge)
+	if (boot_cpu_has(X86_FEATURE_PGE))
 		__write_cr4(cr4);
 }
 
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 19f5736..16e37a25 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -444,11 +444,24 @@
 		pr_debug("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);
 }
 
+/* PAT setup for BP. We need to go through sync steps here */
+void __init mtrr_bp_pat_init(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	prepare_set();
+
+	pat_init();
+
+	post_set();
+	local_irq_restore(flags);
+}
+
 /* Grab all of the MTRR state for this CPU into *state */
 bool __init get_mtrr_state(void)
 {
 	struct mtrr_var_range *vrs;
-	unsigned long flags;
 	unsigned lo, dummy;
 	unsigned int i;
 
@@ -481,15 +494,6 @@
 
 	mtrr_state_set = 1;
 
-	/* PAT setup for BP. We need to go through sync steps here */
-	local_irq_save(flags);
-	prepare_set();
-
-	pat_init();
-
-	post_set();
-	local_irq_restore(flags);
-
 	return !!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED);
 }
 
@@ -741,7 +745,7 @@
 	wbinvd();
 
 	/* Save value of CR4 and clear Page Global Enable (bit 7) */
-	if (cpu_has_pge) {
+	if (boot_cpu_has(X86_FEATURE_PGE)) {
 		cr4 = __read_cr4();
 		__write_cr4(cr4 & ~X86_CR4_PGE);
 	}
@@ -771,7 +775,7 @@
 	write_cr0(read_cr0() & ~X86_CR0_CD);
 
 	/* Restore value of CR4 */
-	if (cpu_has_pge)
+	if (boot_cpu_has(X86_FEATURE_PGE))
 		__write_cr4(cr4);
 	raw_spin_unlock(&set_atomicity_lock);
 }
diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 10f8d47..7d393ec 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -752,6 +752,9 @@
 			/* BIOS may override */
 			__mtrr_enabled = get_mtrr_state();
 
+			if (mtrr_enabled())
+				mtrr_bp_pat_init();
+
 			if (mtrr_cleanup(phys_addr)) {
 				changed_by_mtrr_cleanup = 1;
 				mtrr_if->set_all();
@@ -759,8 +762,16 @@
 		}
 	}
 
-	if (!mtrr_enabled())
+	if (!mtrr_enabled()) {
 		pr_info("MTRR: Disabled\n");
+
+		/*
+		 * PAT initialization relies on MTRR's rendezvous handler.
+		 * Skip PAT init until the handler can initialize both
+		 * features independently.
+		 */
+		pat_disable("MTRRs disabled, skipping PAT initialization too.");
+	}
 }
 
 void mtrr_ap_init(void)
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.h b/arch/x86/kernel/cpu/mtrr/mtrr.h
index 951884d..6c7ced0 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.h
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.h
@@ -52,6 +52,7 @@
 void fill_mtrr_var_range(unsigned int index,
 		u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);
 bool get_mtrr_state(void);
+void mtrr_bp_pat_init(void);
 
 extern void set_mtrr_ops(const struct mtrr_ops *ops);
 
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 364e583..8cac429 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -94,7 +94,7 @@
  */
 static uint32_t __init vmware_platform(void)
 {
-	if (cpu_has_hypervisor) {
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 		unsigned int eax;
 		unsigned int hyper_vendor_id[3];
 
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 1f4acd6..3fe45f8 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -151,7 +151,7 @@
 		return;
 
 	/* Did the boot loader setup the local APIC ? */
-	if (!cpu_has_apic) {
+	if (!boot_cpu_has(X86_FEATURE_APIC)) {
 		if (apic_force_enable(r.start))
 			return;
 	}
diff --git a/arch/x86/kernel/fpu/bugs.c b/arch/x86/kernel/fpu/bugs.c
index dd9ca9b6..aad34aa 100644
--- a/arch/x86/kernel/fpu/bugs.c
+++ b/arch/x86/kernel/fpu/bugs.c
@@ -21,11 +21,15 @@
  * We should really only care about bugs here
  * anyway. Not features.
  */
-static void __init check_fpu(void)
+void __init fpu__init_check_bugs(void)
 {
 	u32 cr0_saved;
 	s32 fdiv_bug;
 
+	/* kernel_fpu_begin/end() relies on patched alternative instructions. */
+	if (!boot_cpu_has(X86_FEATURE_FPU))
+		return;
+
 	/* We might have CR0::TS set already, clear it: */
 	cr0_saved = read_cr0();
 	write_cr0(cr0_saved & ~X86_CR0_TS);
@@ -59,13 +63,3 @@
 		pr_warn("Hmm, FPU with FDIV bug\n");
 	}
 }
-
-void __init fpu__init_check_bugs(void)
-{
-	/*
-	 * kernel_fpu_begin/end() in check_fpu() relies on the patched
-	 * alternative instructions.
-	 */
-	if (cpu_has_fpu)
-		check_fpu();
-}
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 8e37cc8..9702754 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -217,14 +217,14 @@
 
 void fpstate_init(union fpregs_state *state)
 {
-	if (!cpu_has_fpu) {
+	if (!static_cpu_has(X86_FEATURE_FPU)) {
 		fpstate_init_soft(&state->soft);
 		return;
 	}
 
 	memset(state, 0, xstate_size);
 
-	if (cpu_has_fxsr)
+	if (static_cpu_has(X86_FEATURE_FXSR))
 		fpstate_init_fxstate(&state->fxsave);
 	else
 		fpstate_init_fstate(&state->fsave);
@@ -237,7 +237,7 @@
 	dst_fpu->fpregs_active = 0;
 	dst_fpu->last_cpu = -1;
 
-	if (!src_fpu->fpstate_active || !cpu_has_fpu)
+	if (!src_fpu->fpstate_active || !static_cpu_has(X86_FEATURE_FPU))
 		return 0;
 
 	WARN_ON_FPU(src_fpu != &current->thread.fpu);
@@ -506,33 +506,6 @@
  * x87 math exception handling:
  */
 
-static inline unsigned short get_fpu_cwd(struct fpu *fpu)
-{
-	if (cpu_has_fxsr) {
-		return fpu->state.fxsave.cwd;
-	} else {
-		return (unsigned short)fpu->state.fsave.cwd;
-	}
-}
-
-static inline unsigned short get_fpu_swd(struct fpu *fpu)
-{
-	if (cpu_has_fxsr) {
-		return fpu->state.fxsave.swd;
-	} else {
-		return (unsigned short)fpu->state.fsave.swd;
-	}
-}
-
-static inline unsigned short get_fpu_mxcsr(struct fpu *fpu)
-{
-	if (cpu_has_xmm) {
-		return fpu->state.fxsave.mxcsr;
-	} else {
-		return MXCSR_DEFAULT;
-	}
-}
-
 int fpu__exception_code(struct fpu *fpu, int trap_nr)
 {
 	int err;
@@ -547,10 +520,15 @@
 		 * so if this combination doesn't produce any single exception,
 		 * then we have a bad program that isn't synchronizing its FPU usage
 		 * and it will suffer the consequences since we won't be able to
-		 * fully reproduce the context of the exception
+		 * fully reproduce the context of the exception.
 		 */
-		cwd = get_fpu_cwd(fpu);
-		swd = get_fpu_swd(fpu);
+		if (boot_cpu_has(X86_FEATURE_FXSR)) {
+			cwd = fpu->state.fxsave.cwd;
+			swd = fpu->state.fxsave.swd;
+		} else {
+			cwd = (unsigned short)fpu->state.fsave.cwd;
+			swd = (unsigned short)fpu->state.fsave.swd;
+		}
 
 		err = swd & ~cwd;
 	} else {
@@ -560,7 +538,11 @@
 		 * unmasked exception was caught we must mask the exception mask bits
 		 * at 0x1f80, and then use these to mask the exception bits at 0x3f.
 		 */
-		unsigned short mxcsr = get_fpu_mxcsr(fpu);
+		unsigned short mxcsr = MXCSR_DEFAULT;
+
+		if (boot_cpu_has(X86_FEATURE_XMM))
+			mxcsr = fpu->state.fxsave.mxcsr;
+
 		err = ~(mxcsr >> 7) & mxcsr;
 	}
 
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 54c86ff..aacfd7a 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -29,22 +29,22 @@
 	unsigned long cr0;
 	unsigned long cr4_mask = 0;
 
-	if (cpu_has_fxsr)
+	if (boot_cpu_has(X86_FEATURE_FXSR))
 		cr4_mask |= X86_CR4_OSFXSR;
-	if (cpu_has_xmm)
+	if (boot_cpu_has(X86_FEATURE_XMM))
 		cr4_mask |= X86_CR4_OSXMMEXCPT;
 	if (cr4_mask)
 		cr4_set_bits(cr4_mask);
 
 	cr0 = read_cr0();
 	cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */
-	if (!cpu_has_fpu)
+	if (!boot_cpu_has(X86_FEATURE_FPU))
 		cr0 |= X86_CR0_EM;
 	write_cr0(cr0);
 
 	/* Flush out any pending x87 state: */
 #ifdef CONFIG_MATH_EMULATION
-	if (!cpu_has_fpu)
+	if (!boot_cpu_has(X86_FEATURE_FPU))
 		fpstate_init_soft(&current->thread.fpu.state.soft);
 	else
 #endif
@@ -89,7 +89,7 @@
 	}
 
 #ifndef CONFIG_MATH_EMULATION
-	if (!cpu_has_fpu) {
+	if (!boot_cpu_has(X86_FEATURE_FPU)) {
 		pr_emerg("x86/fpu: Giving up, no FPU found and no math emulation present\n");
 		for (;;)
 			asm volatile("hlt");
@@ -106,7 +106,7 @@
 {
 	unsigned int mask = 0;
 
-	if (cpu_has_fxsr) {
+	if (boot_cpu_has(X86_FEATURE_FXSR)) {
 		/* Static because GCC does not get 16-byte stack alignment right: */
 		static struct fxregs_state fxregs __initdata;
 
@@ -212,7 +212,7 @@
 	 * fpu__init_system_xstate().
 	 */
 
-	if (!cpu_has_fpu) {
+	if (!boot_cpu_has(X86_FEATURE_FPU)) {
 		/*
 		 * Disable xsave as we do not support it if i387
 		 * emulation is enabled.
@@ -221,7 +221,7 @@
 		setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
 		xstate_size = sizeof(struct swregs_state);
 	} else {
-		if (cpu_has_fxsr)
+		if (boot_cpu_has(X86_FEATURE_FXSR))
 			xstate_size = sizeof(struct fxregs_state);
 		else
 			xstate_size = sizeof(struct fregs_state);
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 8bd1c00..81422df 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -21,7 +21,10 @@
 {
 	struct fpu *target_fpu = &target->thread.fpu;
 
-	return (cpu_has_fxsr && target_fpu->fpstate_active) ? regset->n : 0;
+	if (boot_cpu_has(X86_FEATURE_FXSR) && target_fpu->fpstate_active)
+		return regset->n;
+	else
+		return 0;
 }
 
 int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
@@ -30,7 +33,7 @@
 {
 	struct fpu *fpu = &target->thread.fpu;
 
-	if (!cpu_has_fxsr)
+	if (!boot_cpu_has(X86_FEATURE_FXSR))
 		return -ENODEV;
 
 	fpu__activate_fpstate_read(fpu);
@@ -47,7 +50,7 @@
 	struct fpu *fpu = &target->thread.fpu;
 	int ret;
 
-	if (!cpu_has_fxsr)
+	if (!boot_cpu_has(X86_FEATURE_FXSR))
 		return -ENODEV;
 
 	fpu__activate_fpstate_write(fpu);
@@ -65,7 +68,7 @@
 	 * update the header bits in the xsave header, indicating the
 	 * presence of FP and SSE state.
 	 */
-	if (cpu_has_xsave)
+	if (boot_cpu_has(X86_FEATURE_XSAVE))
 		fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FPSSE;
 
 	return ret;
@@ -79,7 +82,7 @@
 	struct xregs_state *xsave;
 	int ret;
 
-	if (!cpu_has_xsave)
+	if (!boot_cpu_has(X86_FEATURE_XSAVE))
 		return -ENODEV;
 
 	fpu__activate_fpstate_read(fpu);
@@ -108,7 +111,7 @@
 	struct xregs_state *xsave;
 	int ret;
 
-	if (!cpu_has_xsave)
+	if (!boot_cpu_has(X86_FEATURE_XSAVE))
 		return -ENODEV;
 
 	fpu__activate_fpstate_write(fpu);
@@ -275,10 +278,10 @@
 
 	fpu__activate_fpstate_read(fpu);
 
-	if (!static_cpu_has(X86_FEATURE_FPU))
+	if (!boot_cpu_has(X86_FEATURE_FPU))
 		return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);
 
-	if (!cpu_has_fxsr)
+	if (!boot_cpu_has(X86_FEATURE_FXSR))
 		return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
 					   &fpu->state.fsave, 0,
 					   -1);
@@ -306,10 +309,10 @@
 	fpu__activate_fpstate_write(fpu);
 	fpstate_sanitize_xstate(fpu);
 
-	if (!static_cpu_has(X86_FEATURE_FPU))
+	if (!boot_cpu_has(X86_FEATURE_FPU))
 		return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);
 
-	if (!cpu_has_fxsr)
+	if (!boot_cpu_has(X86_FEATURE_FXSR))
 		return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
 					  &fpu->state.fsave, 0,
 					  -1);
@@ -325,7 +328,7 @@
 	 * update the header bit in the xsave header, indicating the
 	 * presence of FP.
 	 */
-	if (cpu_has_xsave)
+	if (boot_cpu_has(X86_FEATURE_XSAVE))
 		fpu->state.xsave.header.xfeatures |= XFEATURE_MASK_FP;
 	return ret;
 }
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index b48ef35..4ea2a59 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -190,7 +190,7 @@
  */
 void fpu__init_cpu_xstate(void)
 {
-	if (!cpu_has_xsave || !xfeatures_mask)
+	if (!boot_cpu_has(X86_FEATURE_XSAVE) || !xfeatures_mask)
 		return;
 
 	cr4_set_bits(X86_CR4_OSXSAVE);
@@ -280,7 +280,7 @@
 	xstate_comp_offsets[0] = 0;
 	xstate_comp_offsets[1] = offsetof(struct fxregs_state, xmm_space);
 
-	if (!cpu_has_xsaves) {
+	if (!boot_cpu_has(X86_FEATURE_XSAVES)) {
 		for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
 			if (xfeature_enabled(i)) {
 				xstate_comp_offsets[i] = xstate_offsets[i];
@@ -316,13 +316,13 @@
 	WARN_ON_FPU(!on_boot_cpu);
 	on_boot_cpu = 0;
 
-	if (!cpu_has_xsave)
+	if (!boot_cpu_has(X86_FEATURE_XSAVE))
 		return;
 
 	setup_xstate_features();
 	print_xstate_features();
 
-	if (cpu_has_xsaves) {
+	if (boot_cpu_has(X86_FEATURE_XSAVES)) {
 		init_fpstate.xsave.header.xcomp_bv = (u64)1 << 63 | xfeatures_mask;
 		init_fpstate.xsave.header.xfeatures = xfeatures_mask;
 	}
@@ -417,7 +417,7 @@
  */
 static int using_compacted_format(void)
 {
-	return cpu_has_xsaves;
+	return boot_cpu_has(X86_FEATURE_XSAVES);
 }
 
 static void __xstate_dump_leaves(void)
@@ -549,7 +549,7 @@
 	unsigned int eax, ebx, ecx, edx;
 	unsigned int calculated_xstate_size;
 
-	if (!cpu_has_xsaves) {
+	if (!boot_cpu_has(X86_FEATURE_XSAVES)) {
 		/*
 		 * - CPUID function 0DH, sub-function 0:
 		 *    EBX enumerates the size (in bytes) required by
@@ -630,7 +630,7 @@
 	WARN_ON_FPU(!on_boot_cpu);
 	on_boot_cpu = 0;
 
-	if (!cpu_has_xsave) {
+	if (!boot_cpu_has(X86_FEATURE_XSAVE)) {
 		pr_info("x86/fpu: Legacy x87 FPU detected.\n");
 		return;
 	}
@@ -667,7 +667,7 @@
 	pr_info("x86/fpu: Enabled xstate features 0x%llx, context size is %d bytes, using '%s' format.\n",
 		xfeatures_mask,
 		xstate_size,
-		cpu_has_xsaves ? "compacted" : "standard");
+		boot_cpu_has(X86_FEATURE_XSAVES) ? "compacted" : "standard");
 }
 
 /*
@@ -678,7 +678,7 @@
 	/*
 	 * Restore XCR0 on xsave capable CPUs:
 	 */
-	if (cpu_has_xsave)
+	if (boot_cpu_has(X86_FEATURE_XSAVE))
 		xsetbv(XCR_XFEATURE_ENABLED_MASK, xfeatures_mask);
 }
 
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 54cdbd2..6770865 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -561,62 +561,53 @@
 	 */
 	cld
 
-	cmpl $2,(%esp)		# X86_TRAP_NMI
-	je .Lis_nmi		# Ignore NMI
-
-	cmpl $2,%ss:early_recursion_flag
-	je hlt_loop
 	incl %ss:early_recursion_flag
 
-	push %eax		# 16(%esp)
-	push %ecx		# 12(%esp)
-	push %edx		#  8(%esp)
-	push %ds		#  4(%esp)
-	push %es		#  0(%esp)
-	movl $(__KERNEL_DS),%eax
-	movl %eax,%ds
-	movl %eax,%es
+	/* The vector number is in pt_regs->gs */
 
-	cmpl $(__KERNEL_CS),32(%esp)
-	jne 10f
+	cld
+	pushl	%fs		/* pt_regs->fs */
+	movw	$0, 2(%esp)	/* clear high bits (some CPUs leave garbage) */
+	pushl	%es		/* pt_regs->es */
+	movw	$0, 2(%esp)	/* clear high bits (some CPUs leave garbage) */
+	pushl	%ds		/* pt_regs->ds */
+	movw	$0, 2(%esp)	/* clear high bits (some CPUs leave garbage) */
+	pushl	%eax		/* pt_regs->ax */
+	pushl	%ebp		/* pt_regs->bp */
+	pushl	%edi		/* pt_regs->di */
+	pushl	%esi		/* pt_regs->si */
+	pushl	%edx		/* pt_regs->dx */
+	pushl	%ecx		/* pt_regs->cx */
+	pushl	%ebx		/* pt_regs->bx */
 
-	leal 28(%esp),%eax	# Pointer to %eip
-	call early_fixup_exception
-	andl %eax,%eax
-	jnz ex_entry		/* found an exception entry */
+	/* Fix up DS and ES */
+	movl	$(__KERNEL_DS), %ecx
+	movl	%ecx, %ds
+	movl	%ecx, %es
 
-10:
-#ifdef CONFIG_PRINTK
-	xorl %eax,%eax
-	movw %ax,2(%esp)	/* clean up the segment values on some cpus */
-	movw %ax,6(%esp)
-	movw %ax,34(%esp)
-	leal  40(%esp),%eax
-	pushl %eax		/* %esp before the exception */
-	pushl %ebx
-	pushl %ebp
-	pushl %esi
-	pushl %edi
-	movl %cr2,%eax
-	pushl %eax
-	pushl (20+6*4)(%esp)	/* trapno */
-	pushl $fault_msg
-	call printk
-#endif
-	call dump_stack
-hlt_loop:
-	hlt
-	jmp hlt_loop
+	/* Load the vector number into EDX */
+	movl	PT_GS(%esp), %edx
 
-ex_entry:
-	pop %es
-	pop %ds
-	pop %edx
-	pop %ecx
-	pop %eax
-	decl %ss:early_recursion_flag
-.Lis_nmi:
-	addl $8,%esp		/* drop vector number and error code */
+	/* Load GS into pt_regs->gs and clear high bits */
+	movw	%gs, PT_GS(%esp)
+	movw	$0, PT_GS+2(%esp)
+
+	movl	%esp, %eax	/* args are pt_regs (EAX), trapnr (EDX) */
+	call	early_fixup_exception
+
+	popl	%ebx		/* pt_regs->bx */
+	popl	%ecx		/* pt_regs->cx */
+	popl	%edx		/* pt_regs->dx */
+	popl	%esi		/* pt_regs->si */
+	popl	%edi		/* pt_regs->di */
+	popl	%ebp		/* pt_regs->bp */
+	popl	%eax		/* pt_regs->ax */
+	popl	%ds		/* pt_regs->ds */
+	popl	%es		/* pt_regs->es */
+	popl	%fs		/* pt_regs->fs */
+	popl	%gs		/* pt_regs->gs */
+	decl	%ss:early_recursion_flag
+	addl	$4, %esp	/* pop pt_regs->orig_ax */
 	iret
 ENDPROC(early_idt_handler_common)
 
@@ -653,10 +644,14 @@
 	popl %eax
 #endif
 	iret
+
+hlt_loop:
+	hlt
+	jmp hlt_loop
 ENDPROC(ignore_int)
 __INITDATA
 	.align 4
-early_recursion_flag:
+GLOBAL(early_recursion_flag)
 	.long 0
 
 __REFDATA
@@ -721,19 +716,6 @@
 int_msg:
 	.asciz "Unknown interrupt or fault at: %p %p %p\n"
 
-fault_msg:
-/* fault info: */
-	.ascii "BUG: Int %d: CR2 %p\n"
-/* regs pushed in early_idt_handler: */
-	.ascii "     EDI %p  ESI %p  EBP %p  EBX %p\n"
-	.ascii "     ESP %p   ES %p   DS %p\n"
-	.ascii "     EDX %p  ECX %p  EAX %p\n"
-/* fault frame: */
-	.ascii "     vec %p  err %p  EIP %p   CS %p  flg %p\n"
-	.ascii "Stack: %p %p %p %p %p %p %p %p\n"
-	.ascii "       %p %p %p %p %p %p %p %p\n"
-	.asciz "       %p %p %p %p %p %p %p %p\n"
-
 #include "../../x86/xen/xen-head.S"
 
 /*
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 22fbf9d..5df831e 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -20,6 +20,7 @@
 #include <asm/processor-flags.h>
 #include <asm/percpu.h>
 #include <asm/nops.h>
+#include "../entry/calling.h"
 
 #ifdef CONFIG_PARAVIRT
 #include <asm/asm-offsets.h>
@@ -64,6 +65,14 @@
 	 * tables and then reload them.
 	 */
 
+	/*
+	 * Setup stack for verify_cpu(). "-8" because stack_start is defined
+	 * this way, see below. Our best guess is a NULL ptr for stack
+	 * termination heuristics and we don't want to break anything which
+	 * might depend on it (kgdb, ...).
+	 */
+	leaq	(__end_init_task - 8)(%rip), %rsp
+
 	/* Sanitize CPU configuration */
 	call verify_cpu
 
@@ -350,90 +359,48 @@
 	 */
 	cld
 
-	cmpl $2,(%rsp)		# X86_TRAP_NMI
-	je .Lis_nmi		# Ignore NMI
-
-	cmpl $2,early_recursion_flag(%rip)
-	jz  1f
 	incl early_recursion_flag(%rip)
 
-	pushq %rax		# 64(%rsp)
-	pushq %rcx		# 56(%rsp)
-	pushq %rdx		# 48(%rsp)
-	pushq %rsi		# 40(%rsp)
-	pushq %rdi		# 32(%rsp)
-	pushq %r8		# 24(%rsp)
-	pushq %r9		# 16(%rsp)
-	pushq %r10		#  8(%rsp)
-	pushq %r11		#  0(%rsp)
+	/* The vector number is currently in the pt_regs->di slot. */
+	pushq %rsi				/* pt_regs->si */
+	movq 8(%rsp), %rsi			/* RSI = vector number */
+	movq %rdi, 8(%rsp)			/* pt_regs->di = RDI */
+	pushq %rdx				/* pt_regs->dx */
+	pushq %rcx				/* pt_regs->cx */
+	pushq %rax				/* pt_regs->ax */
+	pushq %r8				/* pt_regs->r8 */
+	pushq %r9				/* pt_regs->r9 */
+	pushq %r10				/* pt_regs->r10 */
+	pushq %r11				/* pt_regs->r11 */
+	pushq %rbx				/* pt_regs->bx */
+	pushq %rbp				/* pt_regs->bp */
+	pushq %r12				/* pt_regs->r12 */
+	pushq %r13				/* pt_regs->r13 */
+	pushq %r14				/* pt_regs->r14 */
+	pushq %r15				/* pt_regs->r15 */
 
-	cmpl $__KERNEL_CS,96(%rsp)
-	jne 11f
-
-	cmpl $14,72(%rsp)	# Page fault?
+	cmpq $14,%rsi		/* Page fault? */
 	jnz 10f
-	GET_CR2_INTO(%rdi)	# can clobber any volatile register if pv
+	GET_CR2_INTO(%rdi)	/* Can clobber any volatile register if pv */
 	call early_make_pgtable
 	andl %eax,%eax
-	jz 20f			# All good
+	jz 20f			/* All good */
 
 10:
-	leaq 88(%rsp),%rdi	# Pointer to %rip
+	movq %rsp,%rdi		/* RDI = pt_regs; RSI is already trapnr */
 	call early_fixup_exception
-	andl %eax,%eax
-	jnz 20f			# Found an exception entry
 
-11:
-#ifdef CONFIG_EARLY_PRINTK
-	GET_CR2_INTO(%r9)	# can clobber any volatile register if pv
-	movl 80(%rsp),%r8d	# error code
-	movl 72(%rsp),%esi	# vector number
-	movl 96(%rsp),%edx	# %cs
-	movq 88(%rsp),%rcx	# %rip
-	xorl %eax,%eax
-	leaq early_idt_msg(%rip),%rdi
-	call early_printk
-	cmpl $2,early_recursion_flag(%rip)
-	jz  1f
-	call dump_stack
-#ifdef CONFIG_KALLSYMS	
-	leaq early_idt_ripmsg(%rip),%rdi
-	movq 40(%rsp),%rsi	# %rip again
-	call __print_symbol
-#endif
-#endif /* EARLY_PRINTK */
-1:	hlt
-	jmp 1b
-
-20:	# Exception table entry found or page table generated
-	popq %r11
-	popq %r10
-	popq %r9
-	popq %r8
-	popq %rdi
-	popq %rsi
-	popq %rdx
-	popq %rcx
-	popq %rax
+20:
 	decl early_recursion_flag(%rip)
-.Lis_nmi:
-	addq $16,%rsp		# drop vector number and error code
-	INTERRUPT_RETURN
+	jmp restore_regs_and_iret
 ENDPROC(early_idt_handler_common)
 
 	__INITDATA
 
 	.balign 4
-early_recursion_flag:
+GLOBAL(early_recursion_flag)
 	.long 0
 
-#ifdef CONFIG_EARLY_PRINTK
-early_idt_msg:
-	.asciz "PANIC: early exception %02lx rip %lx:%lx error %lx cr2 %lx\n"
-early_idt_ripmsg:
-	.asciz "RIP %s\n"
-#endif /* CONFIG_EARLY_PRINTK */
-
 #define NEXT_PAGE(name) \
 	.balign	PAGE_SIZE; \
 GLOBAL(name)
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index a1f0e4a..7282c2e 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -773,7 +773,6 @@
 	.mask		= HPET_MASK,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= hpet_resume_counter,
-	.archdata	= { .vclock_mode = VCLOCK_HPET },
 };
 
 static int hpet_clocksource_register(void)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 8079508..dc1207e 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -522,7 +522,7 @@
 	if (boot_cpu_data.cpuid_level < 0)
 		return 0;	/* So we don't blow up on old processors */
 
-	if (cpu_has_hypervisor)
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
 		return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
 
 	return 0;
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index f08ac28..f958391 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -339,8 +339,10 @@
 	.write_cr8 = native_write_cr8,
 #endif
 	.wbinvd = native_wbinvd,
-	.read_msr = native_read_msr_safe,
-	.write_msr = native_write_msr_safe,
+	.read_msr = native_read_msr,
+	.write_msr = native_write_msr,
+	.read_msr_safe = native_read_msr_safe,
+	.write_msr_safe = native_write_msr_safe,
 	.read_pmc = native_read_pmc,
 	.load_tr_desc = native_load_tr_desc,
 	.set_ldt = native_set_ldt,
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6cbab31..50337ea 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -282,7 +282,7 @@
 	struct fpu *next_fpu = &next->fpu;
 	int cpu = smp_processor_id();
 	struct tss_struct *tss = &per_cpu(cpu_tss, cpu);
-	unsigned fsindex, gsindex;
+	unsigned prev_fsindex, prev_gsindex;
 	fpu_switch_t fpu_switch;
 
 	fpu_switch = switch_fpu_prepare(prev_fpu, next_fpu, cpu);
@@ -292,8 +292,8 @@
 	 *
 	 * (e.g. xen_load_tls())
 	 */
-	savesegment(fs, fsindex);
-	savesegment(gs, gsindex);
+	savesegment(fs, prev_fsindex);
+	savesegment(gs, prev_gsindex);
 
 	/*
 	 * Load TLS before restoring any segments so that segment loads
@@ -336,66 +336,104 @@
 	 * Switch FS and GS.
 	 *
 	 * These are even more complicated than DS and ES: they have
-	 * 64-bit bases are that controlled by arch_prctl.  Those bases
-	 * only differ from the values in the GDT or LDT if the selector
-	 * is 0.
+	 * 64-bit bases are that controlled by arch_prctl.  The bases
+	 * don't necessarily match the selectors, as user code can do
+	 * any number of things to cause them to be inconsistent.
 	 *
-	 * Loading the segment register resets the hidden base part of
-	 * the register to 0 or the value from the GDT / LDT.  If the
-	 * next base address zero, writing 0 to the segment register is
-	 * much faster than using wrmsr to explicitly zero the base.
+	 * We don't promise to preserve the bases if the selectors are
+	 * nonzero.  We also don't promise to preserve the base if the
+	 * selector is zero and the base doesn't match whatever was
+	 * most recently passed to ARCH_SET_FS/GS.  (If/when the
+	 * FSGSBASE instructions are enabled, we'll need to offer
+	 * stronger guarantees.)
 	 *
-	 * The thread_struct.fs and thread_struct.gs values are 0
-	 * if the fs and gs bases respectively are not overridden
-	 * from the values implied by fsindex and gsindex.  They
-	 * are nonzero, and store the nonzero base addresses, if
-	 * the bases are overridden.
-	 *
-	 * (fs != 0 && fsindex != 0) || (gs != 0 && gsindex != 0) should
-	 * be impossible.
-	 *
-	 * Therefore we need to reload the segment registers if either
-	 * the old or new selector is nonzero, and we need to override
-	 * the base address if next thread expects it to be overridden.
-	 *
-	 * This code is unnecessarily slow in the case where the old and
-	 * new indexes are zero and the new base is nonzero -- it will
-	 * unnecessarily write 0 to the selector before writing the new
-	 * base address.
-	 *
-	 * Note: This all depends on arch_prctl being the only way that
-	 * user code can override the segment base.  Once wrfsbase and
-	 * wrgsbase are enabled, most of this code will need to change.
+	 * As an invariant,
+	 * (fs != 0 && fsindex != 0) || (gs != 0 && gsindex != 0) is
+	 * impossible.
 	 */
-	if (unlikely(fsindex | next->fsindex | prev->fs)) {
+	if (next->fsindex) {
+		/* Loading a nonzero value into FS sets the index and base. */
 		loadsegment(fs, next->fsindex);
-
-		/*
-		 * If user code wrote a nonzero value to FS, then it also
-		 * cleared the overridden base address.
-		 *
-		 * XXX: if user code wrote 0 to FS and cleared the base
-		 * address itself, we won't notice and we'll incorrectly
-		 * restore the prior base address next time we reschdule
-		 * the process.
-		 */
-		if (fsindex)
-			prev->fs = 0;
+	} else {
+		if (next->fs) {
+			/* Next index is zero but next base is nonzero. */
+			if (prev_fsindex)
+				loadsegment(fs, 0);
+			wrmsrl(MSR_FS_BASE, next->fs);
+		} else {
+			/* Next base and index are both zero. */
+			if (static_cpu_has_bug(X86_BUG_NULL_SEG)) {
+				/*
+				 * We don't know the previous base and can't
+				 * find out without RDMSR.  Forcibly clear it.
+				 */
+				loadsegment(fs, __USER_DS);
+				loadsegment(fs, 0);
+			} else {
+				/*
+				 * If the previous index is zero and ARCH_SET_FS
+				 * didn't change the base, then the base is
+				 * also zero and we don't need to do anything.
+				 */
+				if (prev->fs || prev_fsindex)
+					loadsegment(fs, 0);
+			}
+		}
 	}
-	if (next->fs)
-		wrmsrl(MSR_FS_BASE, next->fs);
-	prev->fsindex = fsindex;
+	/*
+	 * Save the old state and preserve the invariant.
+	 * NB: if prev_fsindex == 0, then we can't reliably learn the base
+	 * without RDMSR because Intel user code can zero it without telling
+	 * us and AMD user code can program any 32-bit value without telling
+	 * us.
+	 */
+	if (prev_fsindex)
+		prev->fs = 0;
+	prev->fsindex = prev_fsindex;
 
-	if (unlikely(gsindex | next->gsindex | prev->gs)) {
+	if (next->gsindex) {
+		/* Loading a nonzero value into GS sets the index and base. */
 		load_gs_index(next->gsindex);
-
-		/* This works (and fails) the same way as fsindex above. */
-		if (gsindex)
-			prev->gs = 0;
+	} else {
+		if (next->gs) {
+			/* Next index is zero but next base is nonzero. */
+			if (prev_gsindex)
+				load_gs_index(0);
+			wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
+		} else {
+			/* Next base and index are both zero. */
+			if (static_cpu_has_bug(X86_BUG_NULL_SEG)) {
+				/*
+				 * We don't know the previous base and can't
+				 * find out without RDMSR.  Forcibly clear it.
+				 *
+				 * This contains a pointless SWAPGS pair.
+				 * Fixing it would involve an explicit check
+				 * for Xen or a new pvop.
+				 */
+				load_gs_index(__USER_DS);
+				load_gs_index(0);
+			} else {
+				/*
+				 * If the previous index is zero and ARCH_SET_GS
+				 * didn't change the base, then the base is
+				 * also zero and we don't need to do anything.
+				 */
+				if (prev->gs || prev_gsindex)
+					load_gs_index(0);
+			}
+		}
 	}
-	if (next->gs)
-		wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
-	prev->gsindex = gsindex;
+	/*
+	 * Save the old state and preserve the invariant.
+	 * NB: if prev_gsindex == 0, then we can't reliably learn the base
+	 * without RDMSR because Intel user code can zero it without telling
+	 * us and AMD user code can program any 32-bit value without telling
+	 * us.
+	 */
+	if (prev_gsindex)
+		prev->gs = 0;
+	prev->gsindex = prev_gsindex;
 
 	switch_fpu_finish(next_fpu, fpu_switch);
 
@@ -566,10 +604,10 @@
 		break;
 	case ARCH_GET_FS: {
 		unsigned long base;
-		if (task->thread.fsindex == FS_TLS_SEL)
-			base = read_32bit_tls(task, FS_TLS);
-		else if (doit)
+		if (doit)
 			rdmsrl(MSR_FS_BASE, base);
+		else if (task->thread.fsindex == FS_TLS_SEL)
+			base = read_32bit_tls(task, FS_TLS);
 		else
 			base = task->thread.fs;
 		ret = put_user(base, (unsigned long __user *)addr);
@@ -577,16 +615,11 @@
 	}
 	case ARCH_GET_GS: {
 		unsigned long base;
-		unsigned gsindex;
-		if (task->thread.gsindex == GS_TLS_SEL)
+		if (doit)
+			rdmsrl(MSR_KERNEL_GS_BASE, base);
+		else if (task->thread.gsindex == GS_TLS_SEL)
 			base = read_32bit_tls(task, GS_TLS);
-		else if (doit) {
-			savesegment(gs, gsindex);
-			if (gsindex)
-				rdmsrl(MSR_KERNEL_GS_BASE, base);
-			else
-				base = task->thread.gs;
-		} else
+		else
 			base = task->thread.gs;
 		ret = put_user(base, (unsigned long __user *)addr);
 		break;
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 548ddf7..6408c09 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -391,7 +391,7 @@
 		put_user_ex(&frame->uc, &frame->puc);
 
 		/* Create the ucontext.  */
-		if (cpu_has_xsave)
+		if (boot_cpu_has(X86_FEATURE_XSAVE))
 			put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
 		else
 			put_user_ex(0, &frame->uc.uc_flags);
@@ -442,7 +442,7 @@
 {
 	unsigned long flags;
 
-	if (cpu_has_xsave)
+	if (boot_cpu_has(X86_FEATURE_XSAVE))
 		flags = UC_FP_XSTATE | UC_SIGCONTEXT_SS;
 	else
 		flags = UC_SIGCONTEXT_SS;
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index a2065d3..1fe4130 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1231,7 +1231,7 @@
 	 * If we couldn't find a local APIC, then get out of here now!
 	 */
 	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
-	    !cpu_has_apic) {
+	    !boot_cpu_has(X86_FEATURE_APIC)) {
 		if (!disable_apic) {
 			pr_err("BIOS bug, local APIC #%d not detected!...\n",
 				boot_cpu_physical_apicid);
diff --git a/arch/x86/kernel/tce_64.c b/arch/x86/kernel/tce_64.c
index ab40954..f386bad 100644
--- a/arch/x86/kernel/tce_64.c
+++ b/arch/x86/kernel/tce_64.c
@@ -40,7 +40,7 @@
 static inline void flush_tce(void* tceaddr)
 {
 	/* a single tce can't cross a cache line */
-	if (cpu_has_clflush)
+	if (boot_cpu_has(X86_FEATURE_CLFLUSH))
 		clflush(tceaddr);
 	else
 		wbinvd();
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index c9c4c7c..38ba6de 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -36,7 +36,7 @@
 
 /* native_sched_clock() is called before tsc_init(), so
    we must start with the TSC soft disabled to prevent
-   erroneous rdtsc usage on !cpu_has_tsc processors */
+   erroneous rdtsc usage on !boot_cpu_has(X86_FEATURE_TSC) processors */
 static int __read_mostly tsc_disabled = -1;
 
 static DEFINE_STATIC_KEY_FALSE(__use_tsc);
@@ -834,15 +834,15 @@
 #ifndef CONFIG_SMP
 	unsigned long cpu_khz_old = cpu_khz;
 
-	if (cpu_has_tsc) {
-		tsc_khz = x86_platform.calibrate_tsc();
-		cpu_khz = tsc_khz;
-		cpu_data(0).loops_per_jiffy =
-			cpufreq_scale(cpu_data(0).loops_per_jiffy,
-					cpu_khz_old, cpu_khz);
-		return 0;
-	} else
+	if (!boot_cpu_has(X86_FEATURE_TSC))
 		return -ENODEV;
+
+	tsc_khz = x86_platform.calibrate_tsc();
+	cpu_khz = tsc_khz;
+	cpu_data(0).loops_per_jiffy = cpufreq_scale(cpu_data(0).loops_per_jiffy,
+						    cpu_khz_old, cpu_khz);
+
+	return 0;
 #else
 	return -ENODEV;
 #endif
@@ -922,9 +922,6 @@
 	struct cpufreq_freqs *freq = data;
 	unsigned long *lpj;
 
-	if (cpu_has(&cpu_data(freq->cpu), X86_FEATURE_CONSTANT_TSC))
-		return 0;
-
 	lpj = &boot_cpu_data.loops_per_jiffy;
 #ifdef CONFIG_SMP
 	if (!(freq->flags & CPUFREQ_CONST_LOOPS))
@@ -954,9 +951,9 @@
 	.notifier_call  = time_cpufreq_notifier
 };
 
-static int __init cpufreq_tsc(void)
+static int __init cpufreq_register_tsc_scaling(void)
 {
-	if (!cpu_has_tsc)
+	if (!boot_cpu_has(X86_FEATURE_TSC))
 		return 0;
 	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
 		return 0;
@@ -965,7 +962,7 @@
 	return 0;
 }
 
-core_initcall(cpufreq_tsc);
+core_initcall(cpufreq_register_tsc_scaling);
 
 #endif /* CONFIG_CPU_FREQ */
 
@@ -1081,7 +1078,7 @@
  */
 int unsynchronized_tsc(void)
 {
-	if (!cpu_has_tsc || tsc_unstable)
+	if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_unstable)
 		return 1;
 
 #ifdef CONFIG_SMP
@@ -1205,7 +1202,7 @@
 
 static int __init init_tsc_clocksource(void)
 {
-	if (!cpu_has_tsc || tsc_disabled > 0 || !tsc_khz)
+	if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz)
 		return 0;
 
 	if (tsc_clocksource_reliable)
@@ -1242,7 +1239,7 @@
 	u64 lpj;
 	int cpu;
 
-	if (!cpu_has_tsc) {
+	if (!boot_cpu_has(X86_FEATURE_TSC)) {
 		setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER);
 		return;
 	}
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index bbbaa802..769af90 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -75,7 +75,7 @@
 		return 0;
 
 	/* Update OSXSAVE bit */
-	if (cpu_has_xsave && best->function == 0x1) {
+	if (boot_cpu_has(X86_FEATURE_XSAVE) && best->function == 0x1) {
 		best->ecx &= ~F(OSXSAVE);
 		if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE))
 			best->ecx |= F(OSXSAVE);
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 1ff4dbb..4c6972f 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -3844,7 +3844,8 @@
 		__reset_rsvds_bits_mask(vcpu, &context->shadow_zero_check,
 					boot_cpu_data.x86_phys_bits,
 					context->shadow_root_level, false,
-					cpu_has_gbpages, true, true);
+					boot_cpu_has(X86_FEATURE_GBPAGES),
+					true, true);
 	else
 		__reset_rsvds_bits_mask_ept(&context->shadow_zero_check,
 					    boot_cpu_data.x86_phys_bits,
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 2f1ea2f..b72743c 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -809,8 +809,7 @@
 
 #define host_clocks					\
 	{VCLOCK_NONE, "none"},				\
-	{VCLOCK_TSC,  "tsc"},				\
-	{VCLOCK_HPET, "hpet"}				\
+	{VCLOCK_TSC,  "tsc"}				\
 
 TRACE_EVENT(kvm_update_master_clock,
 	TP_PROTO(bool use_master_clock, unsigned int host_clock, bool offset_matched),
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ee1c8a9..d5908bd 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3386,7 +3386,7 @@
 		}
 	}
 
-	if (cpu_has_xsaves)
+	if (boot_cpu_has(X86_FEATURE_XSAVES))
 		rdmsrl(MSR_IA32_XSS, host_xss);
 
 	return 0;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9b7798c..12f33e6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2611,7 +2611,7 @@
 		r = KVM_MAX_MCE_BANKS;
 		break;
 	case KVM_CAP_XCRS:
-		r = cpu_has_xsave;
+		r = boot_cpu_has(X86_FEATURE_XSAVE);
 		break;
 	case KVM_CAP_TSC_CONTROL:
 		r = kvm_has_tsc_control;
@@ -3094,7 +3094,7 @@
 
 	/* Set XSTATE_BV and possibly XCOMP_BV.  */
 	xsave->header.xfeatures = xstate_bv;
-	if (cpu_has_xsaves)
+	if (boot_cpu_has(X86_FEATURE_XSAVES))
 		xsave->header.xcomp_bv = host_xcr0 | XSTATE_COMPACTION_ENABLED;
 
 	/*
@@ -3121,7 +3121,7 @@
 static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu,
 					 struct kvm_xsave *guest_xsave)
 {
-	if (cpu_has_xsave) {
+	if (boot_cpu_has(X86_FEATURE_XSAVE)) {
 		memset(guest_xsave, 0, sizeof(struct kvm_xsave));
 		fill_xsave((u8 *) guest_xsave->region, vcpu);
 	} else {
@@ -3139,7 +3139,7 @@
 	u64 xstate_bv =
 		*(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)];
 
-	if (cpu_has_xsave) {
+	if (boot_cpu_has(X86_FEATURE_XSAVE)) {
 		/*
 		 * Here we allow setting states that are not present in
 		 * CPUID leaf 0xD, index 0, EDX:EAX.  This is for compatibility
@@ -3160,7 +3160,7 @@
 static void kvm_vcpu_ioctl_x86_get_xcrs(struct kvm_vcpu *vcpu,
 					struct kvm_xcrs *guest_xcrs)
 {
-	if (!cpu_has_xsave) {
+	if (!boot_cpu_has(X86_FEATURE_XSAVE)) {
 		guest_xcrs->nr_xcrs = 0;
 		return;
 	}
@@ -3176,7 +3176,7 @@
 {
 	int i, r = 0;
 
-	if (!cpu_has_xsave)
+	if (!boot_cpu_has(X86_FEATURE_XSAVE))
 		return -EINVAL;
 
 	if (guest_xcrs->nr_xcrs > KVM_MAX_XCRS || guest_xcrs->flags)
@@ -5865,7 +5865,7 @@
 
 	perf_register_guest_info_callbacks(&kvm_guest_cbs);
 
-	if (cpu_has_xsave)
+	if (boot_cpu_has(X86_FEATURE_XSAVE))
 		host_xcr0 = xgetbv(XCR_XFEATURE_ENABLED_MASK);
 
 	kvm_lapic_init();
@@ -7293,7 +7293,7 @@
 static void fx_init(struct kvm_vcpu *vcpu)
 {
 	fpstate_init(&vcpu->arch.guest_fpu.state);
-	if (cpu_has_xsaves)
+	if (boot_cpu_has(X86_FEATURE_XSAVES))
 		vcpu->arch.guest_fpu.state.xsave.header.xcomp_bv =
 			host_xcr0 | XSTATE_COMPACTION_ENABLED;
 
diff --git a/arch/x86/lib/usercopy_32.c b/arch/x86/lib/usercopy_32.c
index 91d93b9..b559d92 100644
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -612,7 +612,7 @@
 {
 	stac();
 #ifdef CONFIG_X86_INTEL_USERCOPY
-	if (n > 64 && cpu_has_xmm2)
+	if (n > 64 && static_cpu_has(X86_FEATURE_XMM2))
 		n = __copy_user_zeroing_intel_nocache(to, from, n);
 	else
 		__copy_user_zeroing(to, from, n);
@@ -629,7 +629,7 @@
 {
 	stac();
 #ifdef CONFIG_X86_INTEL_USERCOPY
-	if (n > 64 && cpu_has_xmm2)
+	if (n > 64 && static_cpu_has(X86_FEATURE_XMM2))
 		n = __copy_user_intel_nocache(to, from, n);
 	else
 		__copy_user(to, from, n);
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 82447b3..aaeda3f 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -1,5 +1,6 @@
 #include <linux/module.h>
 #include <asm/uaccess.h>
+#include <asm/traps.h>
 
 typedef bool (*ex_handler_t)(const struct exception_table_entry *,
 			    struct pt_regs *, int);
@@ -42,6 +43,33 @@
 }
 EXPORT_SYMBOL(ex_handler_ext);
 
+bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
+			     struct pt_regs *regs, int trapnr)
+{
+	WARN_ONCE(1, "unchecked MSR access error: RDMSR from 0x%x\n",
+		  (unsigned int)regs->cx);
+
+	/* Pretend that the read succeeded and returned 0. */
+	regs->ip = ex_fixup_addr(fixup);
+	regs->ax = 0;
+	regs->dx = 0;
+	return true;
+}
+EXPORT_SYMBOL(ex_handler_rdmsr_unsafe);
+
+bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup,
+			     struct pt_regs *regs, int trapnr)
+{
+	WARN_ONCE(1, "unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x)\n",
+		  (unsigned int)regs->cx,
+		  (unsigned int)regs->dx, (unsigned int)regs->ax);
+
+	/* Pretend that the write succeeded. */
+	regs->ip = ex_fixup_addr(fixup);
+	return true;
+}
+EXPORT_SYMBOL(ex_handler_wrmsr_unsafe);
+
 bool ex_has_fault_handler(unsigned long ip)
 {
 	const struct exception_table_entry *e;
@@ -82,24 +110,46 @@
 	return handler(e, regs, trapnr);
 }
 
+extern unsigned int early_recursion_flag;
+
 /* Restricted version used during very early boot */
-int __init early_fixup_exception(unsigned long *ip)
+void __init early_fixup_exception(struct pt_regs *regs, int trapnr)
 {
-	const struct exception_table_entry *e;
-	unsigned long new_ip;
-	ex_handler_t handler;
+	/* Ignore early NMIs. */
+	if (trapnr == X86_TRAP_NMI)
+		return;
 
-	e = search_exception_tables(*ip);
-	if (!e)
-		return 0;
+	if (early_recursion_flag > 2)
+		goto halt_loop;
 
-	new_ip  = ex_fixup_addr(e);
-	handler = ex_fixup_handler(e);
+	if (regs->cs != __KERNEL_CS)
+		goto fail;
 
-	/* special handling not supported during early boot */
-	if (handler != ex_handler_default)
-		return 0;
+	/*
+	 * The full exception fixup machinery is available as soon as
+	 * the early IDT is loaded.  This means that it is the
+	 * responsibility of extable users to either function correctly
+	 * when handlers are invoked early or to simply avoid causing
+	 * exceptions before they're ready to handle them.
+	 *
+	 * This is better than filtering which handlers can be used,
+	 * because refusing to call a handler here is guaranteed to
+	 * result in a hard-to-debug panic.
+	 *
+	 * Keep in mind that not all vectors actually get here.  Early
+	 * fage faults, for example, are special.
+	 */
+	if (fixup_exception(regs, trapnr))
+		return;
 
-	*ip = new_ip;
-	return 1;
+fail:
+	early_printk("PANIC: early exception 0x%02x IP %lx:%lx error %lx cr2 0x%lx\n",
+		     (unsigned)trapnr, (unsigned long)regs->cs, regs->ip,
+		     regs->orig_ax, read_cr2());
+
+	show_regs(regs);
+
+halt_loop:
+	while (true)
+		halt();
 }
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index 740d7ac..14a9505 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -162,7 +162,7 @@
 	unsigned long ps = memparse(opt, &opt);
 	if (ps == PMD_SIZE) {
 		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
-	} else if (ps == PUD_SIZE && cpu_has_gbpages) {
+	} else if (ps == PUD_SIZE && boot_cpu_has(X86_FEATURE_GBPAGES)) {
 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 	} else {
 		printk(KERN_ERR "hugepagesz: Unsupported page size %lu M\n",
@@ -177,7 +177,7 @@
 static __init int gigantic_pages_init(void)
 {
 	/* With compaction or CMA we can allocate gigantic pages at runtime */
-	if (cpu_has_gbpages && !size_to_hstate(1UL << PUD_SHIFT))
+	if (boot_cpu_has(X86_FEATURE_GBPAGES) && !size_to_hstate(1UL << PUD_SHIFT))
 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 	return 0;
 }
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 9d56f27..372aad2 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -157,23 +157,23 @@
 	 * This will simplify cpa(), which otherwise needs to support splitting
 	 * large pages into small in interrupt context, etc.
 	 */
-	if (cpu_has_pse && !debug_pagealloc_enabled())
+	if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled())
 		page_size_mask |= 1 << PG_LEVEL_2M;
 #endif
 
 	/* Enable PSE if available */
-	if (cpu_has_pse)
+	if (boot_cpu_has(X86_FEATURE_PSE))
 		cr4_set_bits_and_update_boot(X86_CR4_PSE);
 
 	/* Enable PGE if available */
-	if (cpu_has_pge) {
+	if (boot_cpu_has(X86_FEATURE_PGE)) {
 		cr4_set_bits_and_update_boot(X86_CR4_PGE);
 		__supported_pte_mask |= _PAGE_GLOBAL;
 	} else
 		__supported_pte_mask &= ~_PAGE_GLOBAL;
 
 	/* Enable 1 GB linear kernel mappings if available: */
-	if (direct_gbpages && cpu_has_gbpages) {
+	if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) {
 		printk(KERN_INFO "Using GB pages for direct mapping\n");
 		page_size_mask |= 1 << PG_LEVEL_1G;
 	} else {
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index bd7a9b9..85af914 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -284,7 +284,7 @@
 	 */
 	mapping_iter = 1;
 
-	if (!cpu_has_pse)
+	if (!boot_cpu_has(X86_FEATURE_PSE))
 		use_pse = 0;
 
 repeat:
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 214afda..89d9747 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1295,7 +1295,7 @@
 	struct vmem_altmap *altmap = to_vmem_altmap(start);
 	int err;
 
-	if (cpu_has_pse)
+	if (boot_cpu_has(X86_FEATURE_PSE))
 		err = vmemmap_populate_hugepages(start, end, node, altmap);
 	else if (altmap) {
 		pr_err_once("%s: no cpu support for altmap allocations\n",
@@ -1338,7 +1338,7 @@
 		}
 		get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
 
-		if (!cpu_has_pse) {
+		if (!boot_cpu_has(X86_FEATURE_PSE)) {
 			next = (addr + PAGE_SIZE) & PAGE_MASK;
 			pmd = pmd_offset(pud, addr);
 			if (pmd_none(*pmd))
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 0d8d53d..f089491 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -378,7 +378,7 @@
 int __init arch_ioremap_pud_supported(void)
 {
 #ifdef CONFIG_X86_64
-	return cpu_has_gbpages;
+	return boot_cpu_has(X86_FEATURE_GBPAGES);
 #else
 	return 0;
 #endif
@@ -386,7 +386,7 @@
 
 int __init arch_ioremap_pmd_supported(void)
 {
-	return cpu_has_pse;
+	return boot_cpu_has(X86_FEATURE_PSE);
 }
 
 /*
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 01be9ec..bbf462f 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -1055,7 +1055,7 @@
 	/*
 	 * Map everything starting from the Gb boundary, possibly with 1G pages
 	 */
-	while (cpu_has_gbpages && end - start >= PUD_SIZE) {
+	while (boot_cpu_has(X86_FEATURE_GBPAGES) && end - start >= PUD_SIZE) {
 		set_pud(pud, __pud(cpa->pfn << PAGE_SHIFT | _PAGE_PSE |
 				   massage_pgprot(pud_pgprot)));
 
@@ -1460,7 +1460,7 @@
 	 * error case we fall back to cpa_flush_all (which uses
 	 * WBINVD):
 	 */
-	if (!ret && cpu_has_clflush) {
+	if (!ret && boot_cpu_has(X86_FEATURE_CLFLUSH)) {
 		if (cpa.flags & (CPA_PAGES_ARRAY | CPA_ARRAY)) {
 			cpa_flush_array(addr, numpages, cache,
 					cpa.flags, pages);
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index faec01e..fb0604f 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -40,11 +40,22 @@
 static bool boot_cpu_done;
 
 static int __read_mostly __pat_enabled = IS_ENABLED(CONFIG_X86_PAT);
+static void init_cache_modes(void);
 
-static inline void pat_disable(const char *reason)
+void pat_disable(const char *reason)
 {
+	if (!__pat_enabled)
+		return;
+
+	if (boot_cpu_done) {
+		WARN_ONCE(1, "x86/PAT: PAT cannot be disabled after initialization\n");
+		return;
+	}
+
 	__pat_enabled = 0;
 	pr_info("x86/PAT: %s\n", reason);
+
+	init_cache_modes();
 }
 
 static int __init nopat(char *str)
@@ -181,7 +192,7 @@
  * configuration.
  * Using lower indices is preferred, so we start with highest index.
  */
-void pat_init_cache_modes(u64 pat)
+static void __init_cache_modes(u64 pat)
 {
 	enum page_cache_mode cache;
 	char pat_msg[33];
@@ -202,14 +213,11 @@
 {
 	u64 tmp_pat;
 
-	if (!cpu_has_pat) {
+	if (!boot_cpu_has(X86_FEATURE_PAT)) {
 		pat_disable("PAT not supported by CPU.");
 		return;
 	}
 
-	if (!pat_enabled())
-		goto done;
-
 	rdmsrl(MSR_IA32_CR_PAT, tmp_pat);
 	if (!tmp_pat) {
 		pat_disable("PAT MSR is 0, disabled.");
@@ -218,16 +226,12 @@
 
 	wrmsrl(MSR_IA32_CR_PAT, pat);
 
-done:
-	pat_init_cache_modes(pat);
+	__init_cache_modes(pat);
 }
 
 static void pat_ap_init(u64 pat)
 {
-	if (!pat_enabled())
-		return;
-
-	if (!cpu_has_pat) {
+	if (!boot_cpu_has(X86_FEATURE_PAT)) {
 		/*
 		 * If this happens we are on a secondary CPU, but switched to
 		 * PAT on the boot CPU. We have no way to undo PAT.
@@ -238,18 +242,32 @@
 	wrmsrl(MSR_IA32_CR_PAT, pat);
 }
 
-void pat_init(void)
+static void init_cache_modes(void)
 {
-	u64 pat;
-	struct cpuinfo_x86 *c = &boot_cpu_data;
+	u64 pat = 0;
+	static int init_cm_done;
 
-	if (!pat_enabled()) {
+	if (init_cm_done)
+		return;
+
+	if (boot_cpu_has(X86_FEATURE_PAT)) {
+		/*
+		 * CPU supports PAT. Set PAT table to be consistent with
+		 * PAT MSR. This case supports "nopat" boot option, and
+		 * virtual machine environments which support PAT without
+		 * MTRRs. In specific, Xen has unique setup to PAT MSR.
+		 *
+		 * If PAT MSR returns 0, it is considered invalid and emulates
+		 * as No PAT.
+		 */
+		rdmsrl(MSR_IA32_CR_PAT, pat);
+	}
+
+	if (!pat) {
 		/*
 		 * No PAT. Emulate the PAT table that corresponds to the two
-		 * cache bits, PWT (Write Through) and PCD (Cache Disable). This
-		 * setup is the same as the BIOS default setup when the system
-		 * has PAT but the "nopat" boot option has been specified. This
-		 * emulated PAT table is used when MSR_IA32_CR_PAT returns 0.
+		 * cache bits, PWT (Write Through) and PCD (Cache Disable).
+		 * This setup is also the same as the BIOS default setup.
 		 *
 		 * PTE encoding:
 		 *
@@ -266,10 +284,36 @@
 		 */
 		pat = PAT(0, WB) | PAT(1, WT) | PAT(2, UC_MINUS) | PAT(3, UC) |
 		      PAT(4, WB) | PAT(5, WT) | PAT(6, UC_MINUS) | PAT(7, UC);
+	}
 
-	} else if ((c->x86_vendor == X86_VENDOR_INTEL) &&
-		   (((c->x86 == 0x6) && (c->x86_model <= 0xd)) ||
-		    ((c->x86 == 0xf) && (c->x86_model <= 0x6)))) {
+	__init_cache_modes(pat);
+
+	init_cm_done = 1;
+}
+
+/**
+ * pat_init - Initialize PAT MSR and PAT table
+ *
+ * This function initializes PAT MSR and PAT table with an OS-defined value
+ * to enable additional cache attributes, WC and WT.
+ *
+ * This function must be called on all CPUs using the specific sequence of
+ * operations defined in Intel SDM. mtrr_rendezvous_handler() provides this
+ * procedure for PAT.
+ */
+void pat_init(void)
+{
+	u64 pat;
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	if (!pat_enabled()) {
+		init_cache_modes();
+		return;
+	}
+
+	if ((c->x86_vendor == X86_VENDOR_INTEL) &&
+	    (((c->x86 == 0x6) && (c->x86_model <= 0xd)) ||
+	     ((c->x86 == 0xf) && (c->x86_model <= 0x6)))) {
 		/*
 		 * PAT support with the lower four entries. Intel Pentium 2,
 		 * 3, M, and 4 are affected by PAT errata, which makes the
@@ -734,25 +778,6 @@
 	if (file->f_flags & O_DSYNC)
 		pcm = _PAGE_CACHE_MODE_UC_MINUS;
 
-#ifdef CONFIG_X86_32
-	/*
-	 * On the PPro and successors, the MTRRs are used to set
-	 * memory types for physical addresses outside main memory,
-	 * so blindly setting UC or PWT on those pages is wrong.
-	 * For Pentiums and earlier, the surround logic should disable
-	 * caching for the high addresses through the KEN pin, but
-	 * we maintain the tradition of paranoia in this code.
-	 */
-	if (!pat_enabled() &&
-	    !(boot_cpu_has(X86_FEATURE_MTRR) ||
-	      boot_cpu_has(X86_FEATURE_K6_MTRR) ||
-	      boot_cpu_has(X86_FEATURE_CYRIX_ARR) ||
-	      boot_cpu_has(X86_FEATURE_CENTAUR_MCR)) &&
-	    (pfn << PAGE_SHIFT) >= __pa(high_memory)) {
-		pcm = _PAGE_CACHE_MODE_UC;
-	}
-#endif
-
 	*vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) |
 			     cachemode2protval(pcm));
 	return 1;
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index 0e07e09..28c0412 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -636,7 +636,7 @@
 	__u8 cpu_model = boot_cpu_data.x86_model;
 	struct op_x86_model_spec *spec = &op_ppro_spec;	/* default */
 
-	if (force_cpu_type == arch_perfmon && cpu_has_arch_perfmon)
+	if (force_cpu_type == arch_perfmon && boot_cpu_has(X86_FEATURE_ARCH_PERFMON))
 		return 0;
 
 	/*
@@ -700,7 +700,7 @@
 	char *cpu_type = NULL;
 	int ret = 0;
 
-	if (!cpu_has_apic)
+	if (!boot_cpu_has(X86_FEATURE_APIC))
 		return -ENODEV;
 
 	if (force_cpu_type == timer)
@@ -761,7 +761,7 @@
 		if (cpu_type)
 			break;
 
-		if (!cpu_has_arch_perfmon)
+		if (!boot_cpu_has(X86_FEATURE_ARCH_PERFMON))
 			return -ENODEV;
 
 		/* use arch perfmon as fallback */
diff --git a/arch/x86/oprofile/op_model_ppro.c b/arch/x86/oprofile/op_model_ppro.c
index d90528e..350f709 100644
--- a/arch/x86/oprofile/op_model_ppro.c
+++ b/arch/x86/oprofile/op_model_ppro.c
@@ -75,7 +75,7 @@
 	u64 val;
 	int i;
 
-	if (cpu_has_arch_perfmon) {
+	if (boot_cpu_has(X86_FEATURE_ARCH_PERFMON)) {
 		union cpuid10_eax eax;
 		eax.full = cpuid_eax(0xa);
 
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index beac4df..4bd08b0 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -445,7 +445,7 @@
 		uint32_t eax = cpuid_eax(xen_cpuid_base() + 4);
 
 		if (((eax & XEN_HVM_CPUID_X2APIC_VIRT) && x2apic_mode) ||
-		    ((eax & XEN_HVM_CPUID_APIC_ACCESS_VIRT) && cpu_has_apic))
+		    ((eax & XEN_HVM_CPUID_APIC_ACCESS_VIRT) && boot_cpu_has(X86_FEATURE_APIC)))
 			return;
 	}
 
diff --git a/arch/x86/power/hibernate_32.c b/arch/x86/power/hibernate_32.c
index 291226b..9f14bd3 100644
--- a/arch/x86/power/hibernate_32.c
+++ b/arch/x86/power/hibernate_32.c
@@ -106,7 +106,7 @@
 			 * normal page tables.
 			 * NOTE: We can mark everything as executable here
 			 */
-			if (cpu_has_pse) {
+			if (boot_cpu_has(X86_FEATURE_PSE)) {
 				set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
 				pfn += PTRS_PER_PTE;
 			} else {
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 880862c..6ab6722 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -75,7 +75,6 @@
 #include <asm/mach_traps.h>
 #include <asm/mwait.h>
 #include <asm/pci_x86.h>
-#include <asm/pat.h>
 #include <asm/cpu.h>
 
 #ifdef CONFIG_ACPI
@@ -1093,6 +1092,26 @@
 	return ret;
 }
 
+static u64 xen_read_msr(unsigned int msr)
+{
+	/*
+	 * This will silently swallow a #GP from RDMSR.  It may be worth
+	 * changing that.
+	 */
+	int err;
+
+	return xen_read_msr_safe(msr, &err);
+}
+
+static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
+{
+	/*
+	 * This will silently swallow a #GP from WRMSR.  It may be worth
+	 * changing that.
+	 */
+	xen_write_msr_safe(msr, low, high);
+}
+
 void xen_setup_shared_info(void)
 {
 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
@@ -1223,8 +1242,11 @@
 
 	.wbinvd = native_wbinvd,
 
-	.read_msr = xen_read_msr_safe,
-	.write_msr = xen_write_msr_safe,
+	.read_msr = xen_read_msr,
+	.write_msr = xen_write_msr,
+
+	.read_msr_safe = xen_read_msr_safe,
+	.write_msr_safe = xen_write_msr_safe,
 
 	.read_pmc = xen_read_pmc,
 
@@ -1469,10 +1491,10 @@
 	 * For BSP, PSE PGE are set in probe_page_size_mask(), for APs
 	 * set them here. For all, OSFXSR OSXMMEXCPT are set in fpu__init_cpu().
 	*/
-	if (cpu_has_pse)
+	if (boot_cpu_has(X86_FEATURE_PSE))
 		cr4_set_bits_and_update_boot(X86_CR4_PSE);
 
-	if (cpu_has_pge)
+	if (boot_cpu_has(X86_FEATURE_PGE))
 		cr4_set_bits_and_update_boot(X86_CR4_PGE);
 }
 
@@ -1511,7 +1533,6 @@
 {
 	struct physdev_set_iopl set_iopl;
 	unsigned long initrd_start = 0;
-	u64 pat;
 	int rc;
 
 	if (!xen_start_info)
@@ -1618,13 +1639,6 @@
 				   xen_start_info->nr_pages);
 	xen_reserve_special_pages();
 
-	/*
-	 * Modify the cache mode translation tables to match Xen's PAT
-	 * configuration.
-	 */
-	rdmsrl(MSR_IA32_CR_PAT, pat);
-	pat_init_cache_modes(pat);
-
 	/* keep using Xen gdt for now; no urgent need to change it */
 
 #ifdef CONFIG_X86_32
diff --git a/drivers/cpufreq/longhaul.c b/drivers/cpufreq/longhaul.c
index 0f6b229..247bfa8 100644
--- a/drivers/cpufreq/longhaul.c
+++ b/drivers/cpufreq/longhaul.c
@@ -945,7 +945,7 @@
 	}
 #endif
 #ifdef CONFIG_X86_IO_APIC
-	if (cpu_has_apic) {
+	if (boot_cpu_has(X86_FEATURE_APIC)) {
 		printk(KERN_ERR PFX "APIC detected. Longhaul is currently "
 				"broken in this configuration.\n");
 		return -ENODEV;
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 6743ff7..059f7c3 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -72,7 +72,7 @@
 {
 
 #if defined(CONFIG_X86)
-	if (cpu_has_clflush) {
+	if (static_cpu_has(X86_FEATURE_CLFLUSH)) {
 		drm_cache_flush_clflush(pages, num_pages);
 		return;
 	}
@@ -105,7 +105,7 @@
 drm_clflush_sg(struct sg_table *st)
 {
 #if defined(CONFIG_X86)
-	if (cpu_has_clflush) {
+	if (static_cpu_has(X86_FEATURE_CLFLUSH)) {
 		struct sg_page_iter sg_iter;
 
 		mb();
@@ -129,7 +129,7 @@
 drm_clflush_virt_range(void *addr, unsigned long length)
 {
 #if defined(CONFIG_X86)
-	if (cpu_has_clflush) {
+	if (static_cpu_has(X86_FEATURE_CLFLUSH)) {
 		const int size = boot_cpu_data.x86_clflush_size;
 		void *end = addr + length;
 		addr = (void *)(((unsigned long)addr) & -size);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index dabc089..f2cb9a9 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1732,7 +1732,7 @@
 	if (args->flags & ~(I915_MMAP_WC))
 		return -EINVAL;
 
-	if (args->flags & I915_MMAP_WC && !cpu_has_pat)
+	if (args->flags & I915_MMAP_WC && !boot_cpu_has(X86_FEATURE_PAT))
 		return -ENODEV;
 
 	obj = drm_gem_object_lookup(dev, file, args->handle);
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 1328bc5..b845f46 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -488,7 +488,7 @@
 		ret = relocate_entry_cpu(obj, reloc, target_offset);
 	else if (obj->map_and_fenceable)
 		ret = relocate_entry_gtt(obj, reloc, target_offset);
-	else if (cpu_has_clflush)
+	else if (static_cpu_has(X86_FEATURE_CLFLUSH))
 		ret = relocate_entry_clflush(obj, reloc, target_offset);
 	else {
 		WARN_ONCE(1, "Impossible case in relocation handling\n");
diff --git a/drivers/input/joystick/analog.c b/drivers/input/joystick/analog.c
index 6f8b084..3d8ff09 100644
--- a/drivers/input/joystick/analog.c
+++ b/drivers/input/joystick/analog.c
@@ -143,9 +143,9 @@
 
 #include <linux/i8253.h>
 
-#define GET_TIME(x)	do { if (cpu_has_tsc) x = (unsigned int)rdtsc(); else x = get_time_pit(); } while (0)
-#define DELTA(x,y)	(cpu_has_tsc ? ((y) - (x)) : ((x) - (y) + ((x) < (y) ? PIT_TICK_RATE / HZ : 0)))
-#define TIME_NAME	(cpu_has_tsc?"TSC":"PIT")
+#define GET_TIME(x)	do { if (boot_cpu_has(X86_FEATURE_TSC)) x = (unsigned int)rdtsc(); else x = get_time_pit(); } while (0)
+#define DELTA(x,y)	(boot_cpu_has(X86_FEATURE_TSC) ? ((y) - (x)) : ((x) - (y) + ((x) < (y) ? PIT_TICK_RATE / HZ : 0)))
+#define TIME_NAME	(boot_cpu_has(X86_FEATURE_TSC)?"TSC":"PIT")
 static unsigned int get_time_pit(void)
 {
         unsigned long flags;
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index 8adaaea..49721b4 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -36,7 +36,7 @@
 	 * As this gets called during crash dump, keep this simple for
 	 * now.
 	 */
-	if (cpu_has_apic || apic_from_smp_config())
+	if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
 		disconnect_bsp_APIC(0);
 }
 
diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index adc162c..6e9042e 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -603,7 +603,7 @@
 	 * doing this.
 	 */
 	get_online_cpus();
-	if (cpu_has_pge) { /* We have a broader idea of "global". */
+	if (boot_cpu_has(X86_FEATURE_PGE)) { /* We have a broader idea of "global". */
 		/* Remember that this was originally set (for cleanup). */
 		cpu_had_pge = 1;
 		/*
diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c
index 72c9f1f..7c78307 100644
--- a/drivers/net/hamradio/baycom_epp.c
+++ b/drivers/net/hamradio/baycom_epp.c
@@ -635,10 +635,10 @@
 
 #ifdef __i386__
 #include <asm/msr.h>
-#define GETTICK(x)                                                \
-({                                                                \
-	if (cpu_has_tsc)                                          \
-		x = (unsigned int)rdtsc();		  \
+#define GETTICK(x)						\
+({								\
+	if (boot_cpu_has(X86_FEATURE_TSC))			\
+		x = (unsigned int)rdtsc();			\
 })
 #else /* __i386__ */
 #define GETTICK(x)
diff --git a/drivers/staging/unisys/visorbus/visorchipset.c b/drivers/staging/unisys/visorbus/visorchipset.c
index 5fbda7b..9cf4f84 100644
--- a/drivers/staging/unisys/visorbus/visorchipset.c
+++ b/drivers/staging/unisys/visorbus/visorchipset.c
@@ -2425,7 +2425,7 @@
 {
 	unsigned int eax, ebx, ecx, edx;
 
-	if (cpu_has_hypervisor) {
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR)) {
 		/* check the ID */
 		cpuid(UNISYS_SPAR_LEAF_ID, &eax, &ebx, &ecx, &edx);
 		return  (ebx == UNISYS_SPAR_ID_EBX) &&
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 339125b..6a67ab9 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -245,7 +245,9 @@
 
 #define INIT_TASK_DATA(align)						\
 	. = ALIGN(align);						\
-	*(.data..init_task)
+	VMLINUX_SYMBOL(__start_init_task) = .;				\
+	*(.data..init_task)						\
+	VMLINUX_SYMBOL(__end_init_task) = .;
 
 /*
  * Read only Data
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index b47ebd1..c73425de 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -9,6 +9,7 @@
 TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \
 			test_FCMOV test_FCOMI test_FISTTP \
 			vdso_restorer
+TARGETS_C_64BIT_ONLY := fsgsbase
 
 TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY)
 TARGETS_C_64BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_64BIT_ONLY)
diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c
new file mode 100644
index 0000000..5b2b4b3
--- /dev/null
+++ b/tools/testing/selftests/x86/fsgsbase.c
@@ -0,0 +1,398 @@
+/*
+ * fsgsbase.c, an fsgsbase test
+ * Copyright (c) 2014-2016 Andy Lutomirski
+ * GPL v2
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <err.h>
+#include <sys/user.h>
+#include <asm/prctl.h>
+#include <sys/prctl.h>
+#include <signal.h>
+#include <limits.h>
+#include <sys/ucontext.h>
+#include <sched.h>
+#include <linux/futex.h>
+#include <pthread.h>
+#include <asm/ldt.h>
+#include <sys/mman.h>
+
+#ifndef __x86_64__
+# error This test is 64-bit only
+#endif
+
+static volatile sig_atomic_t want_segv;
+static volatile unsigned long segv_addr;
+
+static int nerrs;
+
+static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
+		       int flags)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_sigaction = handler;
+	sa.sa_flags = SA_SIGINFO | flags;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
+static void clearhandler(int sig)
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = SIG_DFL;
+	sigemptyset(&sa.sa_mask);
+	if (sigaction(sig, &sa, 0))
+		err(1, "sigaction");
+}
+
+static void sigsegv(int sig, siginfo_t *si, void *ctx_void)
+{
+	ucontext_t *ctx = (ucontext_t*)ctx_void;
+
+	if (!want_segv) {
+		clearhandler(SIGSEGV);
+		return;  /* Crash cleanly. */
+	}
+
+	want_segv = false;
+	segv_addr = (unsigned long)si->si_addr;
+
+	ctx->uc_mcontext.gregs[REG_RIP] += 4;	/* Skip the faulting mov */
+
+}
+
+enum which_base { FS, GS };
+
+static unsigned long read_base(enum which_base which)
+{
+	unsigned long offset;
+	/*
+	 * Unless we have FSGSBASE, there's no direct way to do this from
+	 * user mode.  We can get at it indirectly using signals, though.
+	 */
+
+	want_segv = true;
+
+	offset = 0;
+	if (which == FS) {
+		/* Use a constant-length instruction here. */
+		asm volatile ("mov %%fs:(%%rcx), %%rax" : : "c" (offset) : "rax");
+	} else {
+		asm volatile ("mov %%gs:(%%rcx), %%rax" : : "c" (offset) : "rax");
+	}
+	if (!want_segv)
+		return segv_addr + offset;
+
+	/*
+	 * If that didn't segfault, try the other end of the address space.
+	 * Unless we get really unlucky and run into the vsyscall page, this
+	 * is guaranteed to segfault.
+	 */
+
+	offset = (ULONG_MAX >> 1) + 1;
+	if (which == FS) {
+		asm volatile ("mov %%fs:(%%rcx), %%rax"
+			      : : "c" (offset) : "rax");
+	} else {
+		asm volatile ("mov %%gs:(%%rcx), %%rax"
+			      : : "c" (offset) : "rax");
+	}
+	if (!want_segv)
+		return segv_addr + offset;
+
+	abort();
+}
+
+static void check_gs_value(unsigned long value)
+{
+	unsigned long base;
+	unsigned short sel;
+
+	printf("[RUN]\tARCH_SET_GS to 0x%lx\n", value);
+	if (syscall(SYS_arch_prctl, ARCH_SET_GS, value) != 0)
+		err(1, "ARCH_SET_GS");
+
+	asm volatile ("mov %%gs, %0" : "=rm" (sel));
+	base = read_base(GS);
+	if (base == value) {
+		printf("[OK]\tGSBASE was set as expected (selector 0x%hx)\n",
+		       sel);
+	} else {
+		nerrs++;
+		printf("[FAIL]\tGSBASE was not as expected: got 0x%lx (selector 0x%hx)\n",
+		       base, sel);
+	}
+
+	if (syscall(SYS_arch_prctl, ARCH_GET_GS, &base) != 0)
+		err(1, "ARCH_GET_GS");
+	if (base == value) {
+		printf("[OK]\tARCH_GET_GS worked as expected (selector 0x%hx)\n",
+		       sel);
+	} else {
+		nerrs++;
+		printf("[FAIL]\tARCH_GET_GS was not as expected: got 0x%lx (selector 0x%hx)\n",
+		       base, sel);
+	}
+}
+
+static void mov_0_gs(unsigned long initial_base, bool schedule)
+{
+	unsigned long base, arch_base;
+
+	printf("[RUN]\tARCH_SET_GS to 0x%lx then mov 0 to %%gs%s\n", initial_base, schedule ? " and schedule " : "");
+	if (syscall(SYS_arch_prctl, ARCH_SET_GS, initial_base) != 0)
+		err(1, "ARCH_SET_GS");
+
+	if (schedule)
+		usleep(10);
+
+	asm volatile ("mov %0, %%gs" : : "rm" (0));
+	base = read_base(GS);
+	if (syscall(SYS_arch_prctl, ARCH_GET_GS, &arch_base) != 0)
+		err(1, "ARCH_GET_GS");
+	if (base == arch_base) {
+		printf("[OK]\tGSBASE is 0x%lx\n", base);
+	} else {
+		nerrs++;
+		printf("[FAIL]\tGSBASE changed to 0x%lx but kernel reports 0x%lx\n", base, arch_base);
+	}
+}
+
+static volatile unsigned long remote_base;
+static volatile bool remote_hard_zero;
+static volatile unsigned int ftx;
+
+/*
+ * ARCH_SET_FS/GS(0) may or may not program a selector of zero.  HARD_ZERO
+ * means to force the selector to zero to improve test coverage.
+ */
+#define HARD_ZERO 0xa1fa5f343cb85fa4
+
+static void do_remote_base()
+{
+	unsigned long to_set = remote_base;
+	bool hard_zero = false;
+	if (to_set == HARD_ZERO) {
+		to_set = 0;
+		hard_zero = true;
+	}
+
+	if (syscall(SYS_arch_prctl, ARCH_SET_GS, to_set) != 0)
+		err(1, "ARCH_SET_GS");
+
+	if (hard_zero)
+		asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+
+	unsigned short sel;
+	asm volatile ("mov %%gs, %0" : "=rm" (sel));
+	printf("\tother thread: ARCH_SET_GS(0x%lx)%s -- sel is 0x%hx\n",
+	       to_set, hard_zero ? " and clear gs" : "", sel);
+}
+
+void do_unexpected_base(void)
+{
+	/*
+	 * The goal here is to try to arrange for GS == 0, GSBASE !=
+	 * 0, and for the the kernel the think that GSBASE == 0.
+	 *
+	 * To make the test as reliable as possible, this uses
+	 * explicit descriptorss.  (This is not the only way.  This
+	 * could use ARCH_SET_GS with a low, nonzero base, but the
+	 * relevant side effect of ARCH_SET_GS could change.)
+	 */
+
+	/* Step 1: tell the kernel that we have GSBASE == 0. */
+	if (syscall(SYS_arch_prctl, ARCH_SET_GS, 0) != 0)
+		err(1, "ARCH_SET_GS");
+
+	/* Step 2: change GSBASE without telling the kernel. */
+	struct user_desc desc = {
+		.entry_number    = 0,
+		.base_addr       = 0xBAADF00D,
+		.limit           = 0xfffff,
+		.seg_32bit       = 1,
+		.contents        = 0, /* Data, grow-up */
+		.read_exec_only  = 0,
+		.limit_in_pages  = 1,
+		.seg_not_present = 0,
+		.useable         = 0
+	};
+	if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) == 0) {
+		printf("\tother thread: using LDT slot 0\n");
+		asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0x7));
+	} else {
+		/* No modify_ldt for us (configured out, perhaps) */
+
+		struct user_desc *low_desc = mmap(
+			NULL, sizeof(desc),
+			PROT_READ | PROT_WRITE,
+			MAP_PRIVATE | MAP_ANONYMOUS | MAP_32BIT, -1, 0);
+		memcpy(low_desc, &desc, sizeof(desc));
+
+		low_desc->entry_number = -1;
+
+		/* 32-bit set_thread_area */
+		long ret;
+		asm volatile ("int $0x80"
+			      : "=a" (ret) : "a" (243), "b" (low_desc)
+			      : "flags");
+		memcpy(&desc, low_desc, sizeof(desc));
+		munmap(low_desc, sizeof(desc));
+
+		if (ret != 0) {
+			printf("[NOTE]\tcould not create a segment -- test won't do anything\n");
+			return;
+		}
+		printf("\tother thread: using GDT slot %d\n", desc.entry_number);
+		asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)((desc.entry_number << 3) | 0x3)));
+	}
+
+	/*
+	 * Step 3: set the selector back to zero.  On AMD chips, this will
+	 * preserve GSBASE.
+	 */
+
+	asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+}
+
+static void *threadproc(void *ctx)
+{
+	while (1) {
+		while (ftx == 0)
+			syscall(SYS_futex, &ftx, FUTEX_WAIT, 0, NULL, NULL, 0);
+		if (ftx == 3)
+			return NULL;
+
+		if (ftx == 1)
+			do_remote_base();
+		else if (ftx == 2)
+			do_unexpected_base();
+		else
+			errx(1, "helper thread got bad command");
+
+		ftx = 0;
+		syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+	}
+}
+
+static void set_gs_and_switch_to(unsigned long local, unsigned long remote)
+{
+	unsigned long base;
+
+	bool hard_zero = false;
+	if (local == HARD_ZERO) {
+		hard_zero = true;
+		local = 0;
+	}
+
+	printf("[RUN]\tARCH_SET_GS(0x%lx)%s, then schedule to 0x%lx\n",
+	       local, hard_zero ? " and clear gs" : "", remote);
+	if (syscall(SYS_arch_prctl, ARCH_SET_GS, local) != 0)
+		err(1, "ARCH_SET_GS");
+	if (hard_zero)
+		asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+
+	if (read_base(GS) != local) {
+		nerrs++;
+		printf("[FAIL]\tGSBASE wasn't set as expected\n");
+	}
+
+	remote_base = remote;
+	ftx = 1;
+	syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+	while (ftx != 0)
+		syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0);
+
+	base = read_base(GS);
+	if (base == local) {
+		printf("[OK]\tGSBASE remained 0x%lx\n", local);
+	} else {
+		nerrs++;
+		printf("[FAIL]\tGSBASE changed to 0x%lx\n", base);
+	}
+}
+
+static void test_unexpected_base(void)
+{
+	unsigned long base;
+
+	printf("[RUN]\tARCH_SET_GS(0), clear gs, then manipulate GSBASE in a different thread\n");
+	if (syscall(SYS_arch_prctl, ARCH_SET_GS, 0) != 0)
+		err(1, "ARCH_SET_GS");
+	asm volatile ("mov %0, %%gs" : : "rm" ((unsigned short)0));
+
+	ftx = 2;
+	syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+	while (ftx != 0)
+		syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0);
+
+	base = read_base(GS);
+	if (base == 0) {
+		printf("[OK]\tGSBASE remained 0\n");
+	} else {
+		nerrs++;
+		printf("[FAIL]\tGSBASE changed to 0x%lx\n", base);
+	}
+}
+
+int main()
+{
+	pthread_t thread;
+
+	sethandler(SIGSEGV, sigsegv, 0);
+
+	check_gs_value(0);
+	check_gs_value(1);
+	check_gs_value(0x200000000);
+	check_gs_value(0);
+	check_gs_value(0x200000000);
+	check_gs_value(1);
+
+	for (int sched = 0; sched < 2; sched++) {
+		mov_0_gs(0, !!sched);
+		mov_0_gs(1, !!sched);
+		mov_0_gs(0x200000000, !!sched);
+	}
+
+	/* Set up for multithreading. */
+
+	cpu_set_t cpuset;
+	CPU_ZERO(&cpuset);
+	CPU_SET(0, &cpuset);
+	if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
+		err(1, "sched_setaffinity to CPU 0");	/* should never fail */
+
+	if (pthread_create(&thread, 0, threadproc, 0) != 0)
+		err(1, "pthread_create");
+
+	static unsigned long bases_with_hard_zero[] = {
+		0, HARD_ZERO, 1, 0x200000000,
+	};
+
+	for (int local = 0; local < 4; local++) {
+		for (int remote = 0; remote < 4; remote++) {
+			set_gs_and_switch_to(bases_with_hard_zero[local],
+					     bases_with_hard_zero[remote]);
+		}
+	}
+
+	test_unexpected_base();
+
+	ftx = 3;  /* Kill the thread. */
+	syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0);
+
+	if (pthread_join(thread, NULL) != 0)
+		err(1, "pthread_join");
+
+	return nerrs == 0 ? 0 : 1;
+}