arch/x86/include/uapi/asm/sigcontext.h - kernel/common - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #ifndef _UAPI_ASM_X86_SIGCONTEXT_H
 #define _UAPI_ASM_X86_SIGCONTEXT_H

 /*
  * Linux signal context definitions. The sigcontext includes a complex
  * hierarchy of CPU and FPU state, available to user-space (on the stack) when
  * a signal handler is executed.
  *
  * As over the years this ABI grew from its very simple roots towards
  * supporting more and more CPU state organically, some of the details (which
  * were rather clever hacks back in the days) became a bit quirky by today.
  *
  * The current ABI includes flexible provisions for future extensions, so we
  * won't have to grow new quirks for quite some time. Promise!
  */

 #include <linux/compiler.h>
 #include <linux/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 512-byte layout of the FXSAVE/FXRSTOR frame
  * are reserved for SW usage. On CPUs supporting XSAVE/XRSTOR, these bytes are
  * used to extend the fpstate pointer in the sigcontext, which now includes the
  * extended state information along with fpstate information.
  *
  * If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then there's a
  * sw_reserved.extended_size bytes large extended context area present. (The
  * last 32-bit word of this extended area (at the
  * fpstate+extended_size-FP_XSTATE_MAGIC2_SIZE address) is set to
  * FP_XSTATE_MAGIC2 so that you can sanity check your size calculations.)
  *
  * This extended area typically grows with newer CPUs that have larger and
  * larger XSAVE areas.
  */
 struct _fpx_sw_bytes {
 	/*
 	 * If set to FP_XSTATE_MAGIC1 then this is an xstate context.
 	 * 0 if a legacy frame.
 	 */
 	__u32				magic1;

 	/*
 	 * Total size of the fpstate area:
 	 *
 	 *  - if magic1 == 0 then it's sizeof(struct _fpstate)
 	 *  - if magic1 == FP_XSTATE_MAGIC1 then it's sizeof(struct _xstate)
 	 *    plus extensions (if any)
 	 */
 	__u32				extended_size;

 	/*
 	 * Feature bit mask (including FP/SSE/extended state) that is present
 	 * in the memory layout:
 	 */
 	__u64				xfeatures;

 	/*
 	 * Actual XSAVE state size, based on the xfeatures saved in the layout.
 	 * 'extended_size' is greater than 'xstate_size':
 	 */
 	__u32				xstate_size;

 	/* For future use: */
 	__u32				padding[7];
 };

 /*
  * As documented in the iBCS2 standard:
  *
  * The first part of "struct _fpstate" is just the normal i387 hardware setup,
  * the extra "status" word is used to save the coprocessor status word before
  * entering the handler.
  *
  * The FPU state data structure has had to grow to accommodate the extended FPU
  * state required by the Streaming SIMD Extensions.  There is no documented
  * standard to accomplish this at the moment.
  */

 /* 10-byte legacy floating point register: */
 struct _fpreg {
 	__u16				significand[4];
 	__u16				exponent;
 };

 /* 16-byte floating point register: */
 struct _fpxreg {
 	__u16				significand[4];
 	__u16				exponent;
 	__u16				padding[3];
 };

 /* 16-byte XMM register: */
 struct _xmmreg {
 	__u32				element[4];
 };

 #define X86_FXSR_MAGIC			0x0000

 /*
  * The 32-bit FPU frame:
  */
 struct _fpstate_32 {
 	/* Legacy FPU environment: */
 	__u32				cw;
 	__u32				sw;
 	__u32				tag;
 	__u32				ipoff;
 	__u32				cssel;
 	__u32				dataoff;
 	__u32				datasel;
 	struct _fpreg			_st[8];
 	__u16				status;
 	__u16				magic;		/* 0xffff: regular FPU data only */
 							/* 0x0000: FXSR FPU data */

 	/* FXSR FPU environment */
 	__u32				_fxsr_env[6];	/* FXSR FPU env is ignored */
 	__u32				mxcsr;
 	__u32				reserved;
 	struct _fpxreg			_fxsr_st[8];	/* FXSR FPU reg data is ignored */
 	struct _xmmreg			_xmm[8];	/* First 8 XMM registers */
 	union {
 		__u32			padding1[44];	/* Second 8 XMM registers plus padding */
 		__u32			padding[44];	/* Alias name for old user-space */
 	};

 	union {
 		__u32			padding2[12];
 		struct _fpx_sw_bytes	sw_reserved;	/* Potential extended state is encoded here */
 	};
 };

 /*
  * The 64-bit FPU frame. (FXSAVE format and later)
  *
  * Note1: If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then the structure is
  *        larger: 'struct _xstate'. Note that 'struct _xstate' embedds
  *        'struct _fpstate' so that you can always assume the _fpstate portion
  *        exists so that you can check the magic value.
  *
  * Note2: Reserved fields may someday contain valuable data. Always
  *	  save/restore them when you change signal frames.
  */
 struct _fpstate_64 {
 	__u16				cwd;
 	__u16				swd;
 	/* Note this is not the same as the 32-bit/x87/FSAVE twd: */
 	__u16				twd;
 	__u16				fop;
 	__u64				rip;
 	__u64				rdp;
 	__u32				mxcsr;
 	__u32				mxcsr_mask;
 	__u32				st_space[32];	/*  8x  FP registers, 16 bytes each */
 	__u32				xmm_space[64];	/* 16x XMM registers, 16 bytes each */
 	__u32				reserved2[12];
 	union {
 		__u32			reserved3[12];
 		struct _fpx_sw_bytes	sw_reserved;	/* Potential extended state is encoded here */
 	};
 };

 #ifdef __i386__
 # define _fpstate _fpstate_32
 #else
 # define _fpstate _fpstate_64
 #endif

 struct _header {
 	__u64				xfeatures;
 	__u64				reserved1[2];
 	__u64				reserved2[5];
 };

 struct _ymmh_state {
 	/* 16x YMM registers, 16 bytes each: */
 	__u32				ymmh_space[64];
 };

 /*
  * Extended state pointed to by sigcontext::fpstate.
  *
  * In addition to the fpstate, information encoded in _xstate::xstate_hdr
  * indicates the presence of other extended state information supported
  * by the CPU and kernel:
  */
 struct _xstate {
 	struct _fpstate			fpstate;
 	struct _header			xstate_hdr;
 	struct _ymmh_state		ymmh;
 	/* New processor state extensions go here: */
 };

 /*
  * The 32-bit signal frame:
  */
 struct sigcontext_32 {
 	__u16				gs, __gsh;
 	__u16				fs, __fsh;
 	__u16				es, __esh;
 	__u16				ds, __dsh;
 	__u32				di;
 	__u32				si;
 	__u32				bp;
 	__u32				sp;
 	__u32				bx;
 	__u32				dx;
 	__u32				cx;
 	__u32				ax;
 	__u32				trapno;
 	__u32				err;
 	__u32				ip;
 	__u16				cs, __csh;
 	__u32				flags;
 	__u32				sp_at_signal;
 	__u16				ss, __ssh;

 	/*
 	 * 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 definition of
 	 * (struct _fpx_sw_bytes)
 	 */
 	__u32				fpstate; /* Zero when no FPU/extended context */
 	__u32				oldmask;
 	__u32				cr2;
 };

 /*
  * The 64-bit signal frame:
  */
 struct sigcontext_64 {
 	__u64				r8;
 	__u64				r9;
 	__u64				r10;
 	__u64				r11;
 	__u64				r12;
 	__u64				r13;
 	__u64				r14;
 	__u64				r15;
 	__u64				di;
 	__u64				si;
 	__u64				bp;
 	__u64				bx;
 	__u64				dx;
 	__u64				ax;
 	__u64				cx;
 	__u64				sp;
 	__u64				ip;
 	__u64				flags;
 	__u16				cs;
 	__u16				gs;
 	__u16				fs;
 	__u16				ss;
 	__u64				err;
 	__u64				trapno;
 	__u64				oldmask;
 	__u64				cr2;

 	/*
 	 * 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 definition of
 	 * (struct _fpx_sw_bytes)
 	 */
 	__u64				fpstate; /* Zero when no FPU/extended context */
 	__u64				reserved1[8];
 };

 /*
  * Create the real 'struct sigcontext' type:
  */
 #ifdef __KERNEL__
 # ifdef __i386__
 #  define sigcontext sigcontext_32
 # else
 #  define sigcontext sigcontext_64
 # endif
 #endif

 /*
  * The old user-space sigcontext definition, just in case user-space still
  * relies on it. The kernel definition (in asm/sigcontext.h) has unified
  * field names but otherwise the same layout.
  */
 #ifndef __KERNEL__

 #define _fpstate_ia32			_fpstate_32
 #define sigcontext_ia32			sigcontext_32


 # ifdef __i386__
 struct sigcontext {
 	__u16				gs, __gsh;
 	__u16				fs, __fsh;
 	__u16				es, __esh;
 	__u16				ds, __dsh;
 	__u32				edi;
 	__u32				esi;
 	__u32				ebp;
 	__u32				esp;
 	__u32				ebx;
 	__u32				edx;
 	__u32				ecx;
 	__u32				eax;
 	__u32				trapno;
 	__u32				err;
 	__u32				eip;
 	__u16				cs, __csh;
 	__u32				eflags;
 	__u32				esp_at_signal;
 	__u16				ss, __ssh;
 	struct _fpstate __user		*fpstate;
 	__u32				oldmask;
 	__u32				cr2;
 };
 # else /* __x86_64__: */
 struct sigcontext {
 	__u64				r8;
 	__u64				r9;
 	__u64				r10;
 	__u64				r11;
 	__u64				r12;
 	__u64				r13;
 	__u64				r14;
 	__u64				r15;
 	__u64				rdi;
 	__u64				rsi;
 	__u64				rbp;
 	__u64				rbx;
 	__u64				rdx;
 	__u64				rax;
 	__u64				rcx;
 	__u64				rsp;
 	__u64				rip;
 	__u64				eflags;		/* RFLAGS */
 	__u16				cs;

 	/*
 	 * Prior to 2.5.64 ("[PATCH] x86-64 updates for 2.5.64-bk3"),
 	 * Linux saved and restored fs and gs in these slots.  This
 	 * was counterproductive, as fsbase and gsbase were never
 	 * saved, so arch_prctl was presumably unreliable.
 	 *
 	 * These slots should never be reused without extreme caution:
 	 *
 	 *  - Some DOSEMU versions stash fs and gs in these slots manually,
 	 *    thus overwriting anything the kernel expects to be preserved
 	 *    in these slots.
 	 *
 	 *  - If these slots are ever needed for any other purpose,
 	 *    there is some risk that very old 64-bit binaries could get
 	 *    confused.  I doubt that many such binaries still work,
 	 *    though, since the same patch in 2.5.64 also removed the
 	 *    64-bit set_thread_area syscall, so it appears that there
 	 *    is no TLS API beyond modify_ldt that works in both pre-
 	 *    and post-2.5.64 kernels.
 	 *
 	 * If the kernel ever adds explicit fs, gs, fsbase, and gsbase
 	 * save/restore, it will most likely need to be opt-in and use
 	 * different context slots.
 	 */
 	__u16				gs;
 	__u16				fs;
 	union {
 		__u16			ss;	/* If UC_SIGCONTEXT_SS */
 		__u16			__pad0;	/* Alias name for old (!UC_SIGCONTEXT_SS) user-space */
 	};
 	__u64				err;
 	__u64				trapno;
 	__u64				oldmask;
 	__u64				cr2;
 	struct _fpstate __user		*fpstate;	/* Zero when no FPU context */
 #  ifdef __ILP32__
 	__u32				__fpstate_pad;
 #  endif
 	__u64				reserved1[8];
 };
 # endif /* __x86_64__ */
 #endif /* !__KERNEL__ */

 #endif /* _UAPI_ASM_X86_SIGCONTEXT_H */
	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
	#ifndef _UAPI_ASM_X86_SIGCONTEXT_H
	#define _UAPI_ASM_X86_SIGCONTEXT_H

	/*
	* Linux signal context definitions. The sigcontext includes a complex
	* hierarchy of CPU and FPU state, available to user-space (on the stack) when
	* a signal handler is executed.
	*
	* As over the years this ABI grew from its very simple roots towards
	* supporting more and more CPU state organically, some of the details (which
	* were rather clever hacks back in the days) became a bit quirky by today.
	*
	* The current ABI includes flexible provisions for future extensions, so we
	* won't have to grow new quirks for quite some time. Promise!
	*/

	#include <linux/compiler.h>
	#include <linux/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 512-byte layout of the FXSAVE/FXRSTOR frame
	* are reserved for SW usage. On CPUs supporting XSAVE/XRSTOR, these bytes are
	* used to extend the fpstate pointer in the sigcontext, which now includes the
	* extended state information along with fpstate information.
	*
	* If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then there's a
	* sw_reserved.extended_size bytes large extended context area present. (The
	* last 32-bit word of this extended area (at the
	* fpstate+extended_size-FP_XSTATE_MAGIC2_SIZE address) is set to
	* FP_XSTATE_MAGIC2 so that you can sanity check your size calculations.)
	*
	* This extended area typically grows with newer CPUs that have larger and
	* larger XSAVE areas.
	*/
	struct _fpx_sw_bytes {
	/*
	* If set to FP_XSTATE_MAGIC1 then this is an xstate context.
	* 0 if a legacy frame.
	*/
	__u32 magic1;

	/*
	* Total size of the fpstate area:
	*
	* - if magic1 == 0 then it's sizeof(struct _fpstate)
	* - if magic1 == FP_XSTATE_MAGIC1 then it's sizeof(struct _xstate)
	* plus extensions (if any)
	*/
	__u32 extended_size;

	/*
	* Feature bit mask (including FP/SSE/extended state) that is present
	* in the memory layout:
	*/
	__u64 xfeatures;

	/*
	* Actual XSAVE state size, based on the xfeatures saved in the layout.
	* 'extended_size' is greater than 'xstate_size':
	*/
	__u32 xstate_size;

	/* For future use: */
	__u32 padding[7];
	};

	/*
	* As documented in the iBCS2 standard:
	*
	* The first part of "struct _fpstate" is just the normal i387 hardware setup,
	* the extra "status" word is used to save the coprocessor status word before
	* entering the handler.
	*
	* The FPU state data structure has had to grow to accommodate the extended FPU
	* state required by the Streaming SIMD Extensions. There is no documented
	* standard to accomplish this at the moment.
	*/

	/* 10-byte legacy floating point register: */
	struct _fpreg {
	__u16 significand[4];
	__u16 exponent;
	};

	/* 16-byte floating point register: */
	struct _fpxreg {
	__u16 significand[4];
	__u16 exponent;
	__u16 padding[3];
	};

	/* 16-byte XMM register: */
	struct _xmmreg {
	__u32 element[4];
	};

	#define X86_FXSR_MAGIC 0x0000

	/*
	* The 32-bit FPU frame:
	*/
	struct _fpstate_32 {
	/* Legacy FPU environment: */
	__u32 cw;
	__u32 sw;
	__u32 tag;
	__u32 ipoff;
	__u32 cssel;
	__u32 dataoff;
	__u32 datasel;
	struct _fpreg _st[8];
	__u16 status;
	__u16 magic; /* 0xffff: regular FPU data only */
	/* 0x0000: FXSR FPU data */

	/* FXSR FPU environment */
	__u32 _fxsr_env[6]; /* FXSR FPU env is ignored */
	__u32 mxcsr;
	__u32 reserved;
	struct _fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */
	struct _xmmreg _xmm[8]; /* First 8 XMM registers */
	union {
	__u32 padding1[44]; /* Second 8 XMM registers plus padding */
	__u32 padding[44]; /* Alias name for old user-space */
	};

	union {
	__u32 padding2[12];
	struct _fpx_sw_bytes sw_reserved; /* Potential extended state is encoded here */
	};
	};

	/*
	* The 64-bit FPU frame. (FXSAVE format and later)
	*
	* Note1: If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then the structure is
	* larger: 'struct _xstate'. Note that 'struct _xstate' embedds
	* 'struct _fpstate' so that you can always assume the _fpstate portion
	* exists so that you can check the magic value.
	*
	* Note2: Reserved fields may someday contain valuable data. Always
	* save/restore them when you change signal frames.
	*/
	struct _fpstate_64 {
	__u16 cwd;
	__u16 swd;
	/* Note this is not the same as the 32-bit/x87/FSAVE twd: */
	__u16 twd;
	__u16 fop;
	__u64 rip;
	__u64 rdp;
	__u32 mxcsr;
	__u32 mxcsr_mask;
	__u32 st_space[32]; /* 8x FP registers, 16 bytes each */
	__u32 xmm_space[64]; /* 16x XMM registers, 16 bytes each */
	__u32 reserved2[12];
	union {
	__u32 reserved3[12];
	struct _fpx_sw_bytes sw_reserved; /* Potential extended state is encoded here */
	};
	};

	#ifdef __i386__
	# define _fpstate _fpstate_32
	#else
	# define _fpstate _fpstate_64
	#endif

	struct _header {
	__u64 xfeatures;
	__u64 reserved1[2];
	__u64 reserved2[5];
	};

	struct _ymmh_state {
	/* 16x YMM registers, 16 bytes each: */
	__u32 ymmh_space[64];
	};

	/*
	* Extended state pointed to by sigcontext::fpstate.
	*
	* In addition to the fpstate, information encoded in _xstate::xstate_hdr
	* indicates the presence of other extended state information supported
	* by the CPU and kernel:
	*/
	struct _xstate {
	struct _fpstate fpstate;
	struct _header xstate_hdr;
	struct _ymmh_state ymmh;
	/* New processor state extensions go here: */
	};

	/*
	* The 32-bit signal frame:
	*/
	struct sigcontext_32 {
	__u16 gs, __gsh;
	__u16 fs, __fsh;
	__u16 es, __esh;
	__u16 ds, __dsh;
	__u32 di;
	__u32 si;
	__u32 bp;
	__u32 sp;
	__u32 bx;
	__u32 dx;
	__u32 cx;
	__u32 ax;
	__u32 trapno;
	__u32 err;
	__u32 ip;
	__u16 cs, __csh;
	__u32 flags;
	__u32 sp_at_signal;
	__u16 ss, __ssh;

	/*
	* 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 definition of
	* (struct _fpx_sw_bytes)
	*/
	__u32 fpstate; /* Zero when no FPU/extended context */
	__u32 oldmask;
	__u32 cr2;
	};

	/*
	* The 64-bit signal frame:
	*/
	struct sigcontext_64 {
	__u64 r8;
	__u64 r9;
	__u64 r10;
	__u64 r11;
	__u64 r12;
	__u64 r13;
	__u64 r14;
	__u64 r15;
	__u64 di;
	__u64 si;
	__u64 bp;
	__u64 bx;
	__u64 dx;
	__u64 ax;
	__u64 cx;
	__u64 sp;
	__u64 ip;
	__u64 flags;
	__u16 cs;
	__u16 gs;
	__u16 fs;
	__u16 ss;
	__u64 err;
	__u64 trapno;
	__u64 oldmask;
	__u64 cr2;

	/*
	* 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 definition of
	* (struct _fpx_sw_bytes)
	*/
	__u64 fpstate; /* Zero when no FPU/extended context */
	__u64 reserved1[8];
	};

	/*
	* Create the real 'struct sigcontext' type:
	*/
	#ifdef __KERNEL__
	# ifdef __i386__
	# define sigcontext sigcontext_32
	# else
	# define sigcontext sigcontext_64
	# endif
	#endif

	/*
	* The old user-space sigcontext definition, just in case user-space still
	* relies on it. The kernel definition (in asm/sigcontext.h) has unified
	* field names but otherwise the same layout.
	*/
	#ifndef __KERNEL__

	#define _fpstate_ia32 _fpstate_32
	#define sigcontext_ia32 sigcontext_32


	# ifdef __i386__
	struct sigcontext {
	__u16 gs, __gsh;
	__u16 fs, __fsh;
	__u16 es, __esh;
	__u16 ds, __dsh;
	__u32 edi;
	__u32 esi;
	__u32 ebp;
	__u32 esp;
	__u32 ebx;
	__u32 edx;
	__u32 ecx;
	__u32 eax;
	__u32 trapno;
	__u32 err;
	__u32 eip;
	__u16 cs, __csh;
	__u32 eflags;
	__u32 esp_at_signal;
	__u16 ss, __ssh;
	struct _fpstate __user *fpstate;
	__u32 oldmask;
	__u32 cr2;
	};
	# else /* __x86_64__: */
	struct sigcontext {
	__u64 r8;
	__u64 r9;
	__u64 r10;
	__u64 r11;
	__u64 r12;
	__u64 r13;
	__u64 r14;
	__u64 r15;
	__u64 rdi;
	__u64 rsi;
	__u64 rbp;
	__u64 rbx;
	__u64 rdx;
	__u64 rax;
	__u64 rcx;
	__u64 rsp;
	__u64 rip;
	__u64 eflags; /* RFLAGS */
	__u16 cs;

	/*
	* Prior to 2.5.64 ("[PATCH] x86-64 updates for 2.5.64-bk3"),
	* Linux saved and restored fs and gs in these slots. This
	* was counterproductive, as fsbase and gsbase were never
	* saved, so arch_prctl was presumably unreliable.
	*
	* These slots should never be reused without extreme caution:
	*
	* - Some DOSEMU versions stash fs and gs in these slots manually,
	* thus overwriting anything the kernel expects to be preserved
	* in these slots.
	*
	* - If these slots are ever needed for any other purpose,
	* there is some risk that very old 64-bit binaries could get
	* confused. I doubt that many such binaries still work,
	* though, since the same patch in 2.5.64 also removed the
	* 64-bit set_thread_area syscall, so it appears that there
	* is no TLS API beyond modify_ldt that works in both pre-
	* and post-2.5.64 kernels.
	*
	* If the kernel ever adds explicit fs, gs, fsbase, and gsbase
	* save/restore, it will most likely need to be opt-in and use
	* different context slots.
	*/
	__u16 gs;
	__u16 fs;
	union {
	__u16 ss; /* If UC_SIGCONTEXT_SS */
	__u16 __pad0; /* Alias name for old (!UC_SIGCONTEXT_SS) user-space */
	};
	__u64 err;
	__u64 trapno;
	__u64 oldmask;
	__u64 cr2;
	struct _fpstate __user fpstate; / Zero when no FPU context */
	# ifdef __ILP32__
	__u32 __fpstate_pad;
	# endif
	__u64 reserved1[8];
	};
	# endif /* __x86_64__ */
	#endif /* !__KERNEL__ */

	#endif /* _UAPI_ASM_X86_SIGCONTEXT_H */