x86 vDSO: consolidate vdso32
This makes x86_64's ia32 emulation support share the sources used in the
32-bit kernel for the 32-bit vDSO and much of its setup code.
The 32-bit vDSO mapping now behaves the same on x86_64 as on native 32-bit.
The abi.syscall32 sysctl on x86_64 now takes the same values that
vm.vdso_enabled takes on the 32-bit kernel. That is, 1 means a randomized
vDSO location, 2 means the fixed old address. The CONFIG_COMPAT_VDSO
option is now available to make this the default setting, the same meaning
it has for the 32-bit kernel. (This does not affect the 64-bit vDSO.)
The argument vdso32=[012] can be used on both 32-bit and 64-bit kernels to
set this paramter at boot time. The vdso=[012] argument still does this
same thing on the 32-bit kernel.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 80b7ba4..2f4d88b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1191,9 +1191,9 @@
config COMPAT_VDSO
bool "Compat VDSO support"
default y
- depends on X86_32
+ depends on X86_32 || IA32_EMULATION
help
- Map the VDSO to the predictable old-style address too.
+ Map the 32-bit VDSO to the predictable old-style address too.
---help---
Say N here if you are running a sufficiently recent glibc
version (2.3.3 or later), to remove the high-mapped
diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile
index a3c997e..1f58a21 100644
--- a/arch/x86/ia32/Makefile
+++ b/arch/x86/ia32/Makefile
@@ -3,7 +3,7 @@
#
obj-$(CONFIG_IA32_EMULATION) := ia32entry.o sys_ia32.o ia32_signal.o tls32.o \
- ia32_binfmt.o fpu32.o ptrace32.o syscall32.o syscall32_syscall.o
+ ia32_binfmt.o fpu32.o ptrace32.o
sysv-$(CONFIG_SYSVIPC) := ipc32.o
obj-$(CONFIG_IA32_EMULATION) += $(sysv-y)
diff --git a/arch/x86/ia32/ia32_binfmt.c b/arch/x86/ia32/ia32_binfmt.c
index 55822d2..e32974c 100644
--- a/arch/x86/ia32/ia32_binfmt.c
+++ b/arch/x86/ia32/ia32_binfmt.c
@@ -26,7 +26,7 @@
#include <asm/i387.h>
#include <asm/uaccess.h>
#include <asm/ia32.h>
-#include <asm/vsyscall32.h>
+#include <asm/vdso.h>
#undef ELF_ARCH
#undef ELF_CLASS
@@ -47,14 +47,13 @@
#define AT_SYSINFO 32
#define AT_SYSINFO_EHDR 33
-int sysctl_vsyscall32 = 1;
+extern int sysctl_vsyscall32;
#undef ARCH_DLINFO
#define ARCH_DLINFO do { \
if (sysctl_vsyscall32) { \
- current->mm->context.vdso = (void *)VSYSCALL32_BASE; \
- NEW_AUX_ENT(AT_SYSINFO, (u32)(u64)VSYSCALL32_VSYSCALL); \
- NEW_AUX_ENT(AT_SYSINFO_EHDR, VSYSCALL32_BASE); \
+ NEW_AUX_ENT(AT_SYSINFO, (u32)VDSO_ENTRY); \
+ NEW_AUX_ENT(AT_SYSINFO_EHDR, (u32)VDSO_CURRENT_BASE); \
} \
} while(0)
diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 0fc5d85..39356a7 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -31,7 +31,7 @@
#include <asm/sigcontext32.h>
#include <asm/fpu32.h>
#include <asm/proto.h>
-#include <asm/vsyscall32.h>
+#include <asm/vdso.h>
#define DEBUG_SIG 0
@@ -465,13 +465,16 @@
goto give_sigsegv;
}
- /* Return stub is in 32bit vsyscall page */
- if (current->binfmt->hasvdso)
- restorer = VSYSCALL32_SIGRETURN;
- else
- restorer = (void *)&frame->retcode;
- if (ka->sa.sa_flags & SA_RESTORER)
+ if (ka->sa.sa_flags & SA_RESTORER) {
restorer = ka->sa.sa_restorer;
+ } else {
+ /* Return stub is in 32bit vsyscall page */
+ if (current->binfmt->hasvdso)
+ restorer = VDSO32_SYMBOL(current->mm->context.vdso,
+ sigreturn);
+ else
+ restorer = (void *)&frame->retcode;
+ }
err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
/*
@@ -519,7 +522,7 @@
{
struct rt_sigframe __user *frame;
struct exec_domain *ed = current_thread_info()->exec_domain;
- void __user *restorer = VSYSCALL32_RTSIGRETURN;
+ void __user *restorer;
int err = 0;
/* __copy_to_user optimizes that into a single 8 byte store */
@@ -564,6 +567,9 @@
if (ka->sa.sa_flags & SA_RESTORER)
restorer = ka->sa.sa_restorer;
+ else
+ restorer = VDSO32_SYMBOL(current->mm->context.vdso,
+ rt_sigreturn);
err |= __put_user(ptr_to_compat(restorer), &frame->pretcode);
/*
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index 1127c71..47bc276 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -15,7 +15,7 @@
# files to link into kernel
obj-$(VDSO64-y) += vma.o vdso.o
-obj-$(CONFIG_X86_32) += vdso32.o vdso32-setup.o
+obj-$(VDSO32-y) += vdso32.o vdso32-setup.o
vobjs := $(foreach F,$(vobjs-y),$(obj)/$F)
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index fb71a93c..d97a6d7 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -24,6 +24,7 @@
#include <asm/elf.h>
#include <asm/tlbflush.h>
#include <asm/vdso.h>
+#include <asm/proto.h>
enum {
VDSO_DISABLED = 0,
@@ -37,14 +38,24 @@
#define VDSO_DEFAULT VDSO_ENABLED
#endif
+#ifdef CONFIG_X86_64
+#define vdso_enabled sysctl_vsyscall32
+#define arch_setup_additional_pages syscall32_setup_pages
+#endif
+
+/*
+ * This is the difference between the prelinked addresses in the vDSO images
+ * and the VDSO_HIGH_BASE address where CONFIG_COMPAT_VDSO places the vDSO
+ * in the user address space.
+ */
+#define VDSO_ADDR_ADJUST (VDSO_HIGH_BASE - (unsigned long)VDSO32_PRELINK)
+
/*
* Should the kernel map a VDSO page into processes and pass its
* address down to glibc upon exec()?
*/
unsigned int __read_mostly vdso_enabled = VDSO_DEFAULT;
-EXPORT_SYMBOL_GPL(vdso_enabled);
-
static int __init vdso_setup(char *s)
{
vdso_enabled = simple_strtoul(s, NULL, 0);
@@ -52,9 +63,18 @@
return 1;
}
-__setup("vdso=", vdso_setup);
+/*
+ * For consistency, the argument vdso32=[012] affects the 32-bit vDSO
+ * behavior on both 64-bit and 32-bit kernels.
+ * On 32-bit kernels, vdso=[012] means the same thing.
+ */
+__setup("vdso32=", vdso_setup);
-extern asmlinkage void ia32_sysenter_target(void);
+#ifdef CONFIG_X86_32
+__setup_param("vdso=", vdso32_setup, vdso_setup, 0);
+
+EXPORT_SYMBOL_GPL(vdso_enabled);
+#endif
static __init void reloc_symtab(Elf32_Ehdr *ehdr,
unsigned offset, unsigned size)
@@ -79,7 +99,7 @@
case STT_FUNC:
case STT_SECTION:
case STT_FILE:
- sym->st_value += VDSO_HIGH_BASE;
+ sym->st_value += VDSO_ADDR_ADJUST;
}
}
}
@@ -105,7 +125,7 @@
case DT_VERNEED:
case DT_ADDRRNGLO ... DT_ADDRRNGHI:
/* definitely pointers needing relocation */
- dyn->d_un.d_ptr += VDSO_HIGH_BASE;
+ dyn->d_un.d_ptr += VDSO_ADDR_ADJUST;
break;
case DT_ENCODING ... OLD_DT_LOOS-1:
@@ -114,7 +134,7 @@
they're even */
if (dyn->d_tag >= DT_ENCODING &&
(dyn->d_tag & 1) == 0)
- dyn->d_un.d_ptr += VDSO_HIGH_BASE;
+ dyn->d_un.d_ptr += VDSO_ADDR_ADJUST;
break;
case DT_VERDEFNUM:
@@ -143,15 +163,15 @@
int i;
BUG_ON(memcmp(ehdr->e_ident, ELFMAG, 4) != 0 ||
- !elf_check_arch(ehdr) ||
+ !elf_check_arch_ia32(ehdr) ||
ehdr->e_type != ET_DYN);
- ehdr->e_entry += VDSO_HIGH_BASE;
+ ehdr->e_entry += VDSO_ADDR_ADJUST;
/* rebase phdrs */
phdr = (void *)ehdr + ehdr->e_phoff;
for (i = 0; i < ehdr->e_phnum; i++) {
- phdr[i].p_vaddr += VDSO_HIGH_BASE;
+ phdr[i].p_vaddr += VDSO_ADDR_ADJUST;
/* relocate dynamic stuff */
if (phdr[i].p_type == PT_DYNAMIC)
@@ -164,7 +184,7 @@
if (!(shdr[i].sh_flags & SHF_ALLOC))
continue;
- shdr[i].sh_addr += VDSO_HIGH_BASE;
+ shdr[i].sh_addr += VDSO_ADDR_ADJUST;
if (shdr[i].sh_type == SHT_SYMTAB ||
shdr[i].sh_type == SHT_DYNSYM)
@@ -173,6 +193,45 @@
}
}
+/*
+ * These symbols are defined by vdso32.S to mark the bounds
+ * of the ELF DSO images included therein.
+ */
+extern const char vdso32_default_start, vdso32_default_end;
+extern const char vdso32_sysenter_start, vdso32_sysenter_end;
+static struct page *vdso32_pages[1];
+
+#ifdef CONFIG_X86_64
+
+static int use_sysenter __read_mostly = -1;
+
+#define vdso32_sysenter() (use_sysenter > 0)
+
+/* May not be __init: called during resume */
+void syscall32_cpu_init(void)
+{
+ if (use_sysenter < 0)
+ use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL);
+
+ /* Load these always in case some future AMD CPU supports
+ SYSENTER from compat mode too. */
+ checking_wrmsrl(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
+ checking_wrmsrl(MSR_IA32_SYSENTER_ESP, 0ULL);
+ checking_wrmsrl(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
+
+ wrmsrl(MSR_CSTAR, ia32_cstar_target);
+}
+
+#define compat_uses_vma 1
+
+static inline void map_compat_vdso(int map)
+{
+}
+
+#else /* CONFIG_X86_32 */
+
+#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP))
+
void enable_sep_cpu(void)
{
int cpu = get_cpu();
@@ -210,13 +269,7 @@
return 0;
}
-/*
- * These symbols are defined by vsyscall.o to mark the bounds
- * of the ELF DSO images included therein.
- */
-extern const char vsyscall_int80_start, vsyscall_int80_end;
-extern const char vsyscall_sysenter_start, vsyscall_sysenter_end;
-static struct page *syscall_pages[1];
+#define compat_uses_vma 0
static void map_compat_vdso(int map)
{
@@ -227,31 +280,35 @@
vdso_mapped = map;
- __set_fixmap(FIX_VDSO, page_to_pfn(syscall_pages[0]) << PAGE_SHIFT,
+ __set_fixmap(FIX_VDSO, page_to_pfn(vdso32_pages[0]) << PAGE_SHIFT,
map ? PAGE_READONLY_EXEC : PAGE_NONE);
/* flush stray tlbs */
flush_tlb_all();
}
+#endif /* CONFIG_X86_64 */
+
int __init sysenter_setup(void)
{
void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
const void *vsyscall;
size_t vsyscall_len;
- syscall_pages[0] = virt_to_page(syscall_page);
+ vdso32_pages[0] = virt_to_page(syscall_page);
+#ifdef CONFIG_X86_32
gate_vma_init();
printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO));
+#endif
- if (!boot_cpu_has(X86_FEATURE_SEP)) {
- vsyscall = &vsyscall_int80_start;
- vsyscall_len = &vsyscall_int80_end - &vsyscall_int80_start;
+ if (!vdso32_sysenter()) {
+ vsyscall = &vdso32_default_start;
+ vsyscall_len = &vdso32_default_end - &vdso32_default_start;
} else {
- vsyscall = &vsyscall_sysenter_start;
- vsyscall_len = &vsyscall_sysenter_end - &vsyscall_sysenter_start;
+ vsyscall = &vdso32_sysenter_start;
+ vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
}
memcpy(syscall_page, vsyscall, vsyscall_len);
@@ -284,7 +341,9 @@
ret = addr;
goto up_fail;
}
+ }
+ if (compat_uses_vma || !compat) {
/*
* MAYWRITE to allow gdb to COW and set breakpoints
*
@@ -298,7 +357,7 @@
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
VM_ALWAYSDUMP,
- syscall_pages);
+ vdso32_pages);
if (ret)
goto up_fail;
@@ -314,6 +373,12 @@
return ret;
}
+#ifdef CONFIG_X86_64
+
+__initcall(sysenter_setup);
+
+#else /* CONFIG_X86_32 */
+
const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
@@ -342,3 +407,5 @@
{
return 0;
}
+
+#endif /* CONFIG_X86_64 */
diff --git a/arch/x86/vdso/vdso32.S b/arch/x86/vdso/vdso32.S
index cab020c..1e36f72 100644
--- a/arch/x86/vdso/vdso32.S
+++ b/arch/x86/vdso/vdso32.S
@@ -2,14 +2,18 @@
__INITDATA
- .globl vsyscall_int80_start, vsyscall_int80_end
-vsyscall_int80_start:
+ .globl vdso32_default_start, vdso32_default_end
+vdso32_default_start:
+#ifdef CONFIG_X86_32
.incbin "arch/x86/vdso/vdso32-int80.so"
-vsyscall_int80_end:
+#else
+ .incbin "arch/x86/vdso/vdso32-syscall.so"
+#endif
+vdso32_default_end:
- .globl vsyscall_sysenter_start, vsyscall_sysenter_end
-vsyscall_sysenter_start:
+ .globl vdso32_sysenter_start, vdso32_sysenter_end
+vdso32_sysenter_start:
.incbin "arch/x86/vdso/vdso32-sysenter.so"
-vsyscall_sysenter_end:
+vdso32_sysenter_end:
__FINIT
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index fd91568..7d6d0ef 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -62,8 +62,8 @@
*/
static void fiddle_vdso(void)
{
- extern char vsyscall_int80_start;
- u32 *mask = VDSO32_SYMBOL(&vsyscall_int80_start, NOTE_MASK);
+ extern const char vdso32_default_start;
+ u32 *mask = VDSO32_SYMBOL(&vdso32_default_start, NOTE_MASK);
*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
}