x86, xsave: struct _fpstate extensions to include extended state information
Bytes 464..511 in the current 512byte layout of fxsave/fxrstor
frame, are reserved for SW usage. On cpu's supporting xsave/xrstor, these bytes
are used to extended the fpstate pointer in the sigcontext, which now includes
the extended state information along with fpstate information.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 77b7af6..eb4bd8c 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -322,7 +322,12 @@
/* 16*16 bytes for each XMM-reg = 256 bytes: */
u32 xmm_space[64];
- u32 padding[24];
+ u32 padding[12];
+
+ union {
+ u32 padding1[12];
+ u32 sw_reserved[12];
+ };
} __attribute__((aligned(16)));
diff --git a/include/asm-x86/sigcontext.h b/include/asm-x86/sigcontext.h
index 24879c8..899fe2f 100644
--- a/include/asm-x86/sigcontext.h
+++ b/include/asm-x86/sigcontext.h
@@ -4,6 +4,40 @@
#include <linux/compiler.h>
#include <asm/types.h>
+#define FP_XSTATE_MAGIC1 0x46505853U
+#define FP_XSTATE_MAGIC2 0x46505845U
+#define FP_XSTATE_MAGIC2_SIZE sizeof(FP_XSTATE_MAGIC2)
+
+/*
+ * bytes 464..511 in the current 512byte layout of fxsave/fxrstor frame
+ * are reserved for SW usage. On cpu's supporting xsave/xrstor, these bytes
+ * are used to extended the fpstate pointer in the sigcontext, which now
+ * includes the extended state information along with fpstate information.
+ *
+ * Presence of FP_XSTATE_MAGIC1 at the beginning of this SW reserved
+ * area and FP_XSTATE_MAGIC2 at the end of memory layout
+ * (extended_size - FP_XSTATE_MAGIC2_SIZE) indicates the presence of the
+ * extended state information in the memory layout pointed by the fpstate
+ * pointer in sigcontext.
+ */
+struct _fpx_sw_bytes {
+ __u32 magic1; /* FP_XSTATE_MAGIC1 */
+ __u32 extended_size; /* total size of the layout referred by
+ * fpstate pointer in the sigcontext.
+ */
+ __u64 xstate_bv;
+ /* feature bit mask (including fp/sse/extended
+ * state) that is present in the memory
+ * layout.
+ */
+ __u32 xstate_size; /* actual xsave state size, based on the
+ * features saved in the layout.
+ * 'extended_size' will be greater than
+ * 'xstate_size'.
+ */
+ __u32 padding[7]; /* for future use. */
+};
+
#ifdef __i386__
/*
* As documented in the iBCS2 standard..
@@ -53,7 +87,13 @@
unsigned long reserved;
struct _fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */
struct _xmmreg _xmm[8];
- unsigned long padding[56];
+ unsigned long padding1[44];
+
+ union {
+ unsigned long padding2[12];
+ struct _fpx_sw_bytes sw_reserved; /* represents the extended
+ * state info */
+ };
};
#define X86_FXSR_MAGIC 0x0000
@@ -79,7 +119,15 @@
unsigned long flags;
unsigned long sp_at_signal;
unsigned short ss, __ssh;
- struct _fpstate __user *fpstate;
+
+ /*
+ * fpstate is really (struct _fpstate *) or (struct _xstate *)
+ * depending on the FP_XSTATE_MAGIC1 encoded in the SW reserved
+ * bytes of (struct _fpstate) and FP_XSTATE_MAGIC2 present at the end
+ * of extended memory layout. See comments at the defintion of
+ * (struct _fpx_sw_bytes)
+ */
+ void __user *fpstate; /* zero when no FPU/extended context */
unsigned long oldmask;
unsigned long cr2;
};
@@ -130,7 +178,12 @@
__u32 mxcsr_mask;
__u32 st_space[32]; /* 8*16 bytes for each FP-reg */
__u32 xmm_space[64]; /* 16*16 bytes for each XMM-reg */
- __u32 reserved2[24];
+ __u32 reserved2[12];
+ union {
+ __u32 reserved3[12];
+ struct _fpx_sw_bytes sw_reserved; /* represents the extended
+ * state information */
+ };
};
#ifdef __KERNEL__
@@ -161,7 +214,15 @@
unsigned long trapno;
unsigned long oldmask;
unsigned long cr2;
- struct _fpstate __user *fpstate; /* zero when no FPU context */
+
+ /*
+ * fpstate is really (struct _fpstate *) or (struct _xstate *)
+ * depending on the FP_XSTATE_MAGIC1 encoded in the SW reserved
+ * bytes of (struct _fpstate) and FP_XSTATE_MAGIC2 present at the end
+ * of extended memory layout. See comments at the defintion of
+ * (struct _fpx_sw_bytes)
+ */
+ void __user *fpstate; /* zero when no FPU/extended context */
unsigned long reserved1[8];
};
#else /* __KERNEL__ */
@@ -202,4 +263,22 @@
#endif /* !__i386__ */
+struct _xsave_hdr {
+ u64 xstate_bv;
+ u64 reserved1[2];
+ u64 reserved2[5];
+};
+
+/*
+ * Extended state pointed by the fpstate pointer in the sigcontext.
+ * In addition to the fpstate, information encoded in the xstate_hdr
+ * indicates the presence of other extended state information
+ * supported by the processor and OS.
+ */
+struct _xstate {
+ struct _fpstate fpstate;
+ struct _xsave_hdr xstate_hdr;
+ /* new processor state extensions go here */
+};
+
#endif /* ASM_X86__SIGCONTEXT_H */
diff --git a/include/asm-x86/sigcontext32.h b/include/asm-x86/sigcontext32.h
index 4e2ec73..8c34703 100644
--- a/include/asm-x86/sigcontext32.h
+++ b/include/asm-x86/sigcontext32.h
@@ -40,7 +40,11 @@
__u32 reserved;
struct _fpxreg _fxsr_st[8];
struct _xmmreg _xmm[8]; /* It's actually 16 */
- __u32 padding[56];
+ __u32 padding[44];
+ union {
+ __u32 padding2[12];
+ struct _fpx_sw_bytes sw_reserved;
+ };
};
struct sigcontext_ia32 {