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Commit bdd8caba authored by Suresh Siddha's avatar Suresh Siddha Committed by Ingo Molnar
Browse files

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: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 9dc89c0f

include/asm-x86/processor.h

+6 −1
Original line number Diff line number Diff line
@@ -322,7 +322,12 @@ struct i387_fxsave_struct { 
	/* 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)));

include/asm-x86/sigcontext.h

+83 −4
Original line number Diff line number Diff line
@@ -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 @@ struct _fpstate { 
	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 @@ struct sigcontext { 
	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 @@ struct _fpstate { 
	__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 @@ struct sigcontext { 
	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 @@ struct sigcontext { 


#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 */

include/asm-x86/sigcontext32.h

+5 −1
Original line number Diff line number Diff line
@@ -40,7 +40,11 @@ struct _fpstate_ia32 { 
	__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 {