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 --- Index: tip-0728/include/asm-x86/sigcontext.h =================================================================== --- tip-0728.orig/include/asm-x86/sigcontext.h 2008-07-28 18:42:45.000000000 -0700 +++ tip-0728/include/asm-x86/sigcontext.h 2008-07-28 18:44:20.000000000 -0700 @@ -4,6 +4,40 @@ #include #include +#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 +119,14 @@ 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 +177,12 @@ __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 +213,14 @@ 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 +261,22 @@ #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 */ Index: tip-0728/include/asm-x86/sigcontext32.h =================================================================== --- tip-0728.orig/include/asm-x86/sigcontext32.h 2008-07-28 18:42:45.000000000 -0700 +++ tip-0728/include/asm-x86/sigcontext32.h 2008-07-28 18:43:47.000000000 -0700 @@ -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 { Index: tip-0728/include/asm-x86/processor.h =================================================================== --- tip-0728.orig/include/asm-x86/processor.h 2008-07-28 18:42:45.000000000 -0700 +++ tip-0728/include/asm-x86/processor.h 2008-07-28 18:43:47.000000000 -0700 @@ -327,7 +327,12 @@ /* 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))); -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/