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/usr/include/x86_64-linux-gnu/asm/sigcontext.h


$ cat -n /usr/include/x86_64-linux-gnu/asm/sigcontext.h

     1	/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
     2	#ifndef _ASM_X86_SIGCONTEXT_H
     3	#define _ASM_X86_SIGCONTEXT_H
     4	
     5	/*
     6	 * Linux signal context definitions. The sigcontext includes a complex
     7	 * hierarchy of CPU and FPU state, available to user-space (on the stack) when
     8	 * a signal handler is executed.
     9	 *
    10	 * As over the years this ABI grew from its very simple roots towards
    11	 * supporting more and more CPU state organically, some of the details (which
    12	 * were rather clever hacks back in the days) became a bit quirky by today.
    13	 *
    14	 * The current ABI includes flexible provisions for future extensions, so we
    15	 * won't have to grow new quirks for quite some time. Promise!
    16	 */
    17	
    18	
    19	#include <linux/types.h>
    20	
    21	#define FP_XSTATE_MAGIC1		0x46505853U
    22	#define FP_XSTATE_MAGIC2		0x46505845U
    23	#define FP_XSTATE_MAGIC2_SIZE		sizeof(FP_XSTATE_MAGIC2)
    24	
    25	/*
    26	 * Bytes 464..511 in the current 512-byte layout of the FXSAVE/FXRSTOR frame
    27	 * are reserved for SW usage. On CPUs supporting XSAVE/XRSTOR, these bytes are
    28	 * used to extend the fpstate pointer in the sigcontext, which now includes the
    29	 * extended state information along with fpstate information.
    30	 *
    31	 * If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then there's a
    32	 * sw_reserved.extended_size bytes large extended context area present. (The
    33	 * last 32-bit word of this extended area (at the
    34	 * fpstate+extended_size-FP_XSTATE_MAGIC2_SIZE address) is set to
    35	 * FP_XSTATE_MAGIC2 so that you can sanity check your size calculations.)
    36	 *
    37	 * This extended area typically grows with newer CPUs that have larger and
    38	 * larger XSAVE areas.
    39	 */
    40	struct _fpx_sw_bytes {
    41		/*
    42		 * If set to FP_XSTATE_MAGIC1 then this is an xstate context.
    43		 * 0 if a legacy frame.
    44		 */
    45		__u32				magic1;
    46	
    47		/*
    48		 * Total size of the fpstate area:
    49		 *
    50		 *  - if magic1 == 0 then it's sizeof(struct _fpstate)
    51		 *  - if magic1 == FP_XSTATE_MAGIC1 then it's sizeof(struct _xstate)
    52		 *    plus extensions (if any)
    53		 */
    54		__u32				extended_size;
    55	
    56		/*
    57		 * Feature bit mask (including FP/SSE/extended state) that is present
    58		 * in the memory layout:
    59		 */
    60		__u64				xfeatures;
    61	
    62		/*
    63		 * Actual XSAVE state size, based on the xfeatures saved in the layout.
    64		 * 'extended_size' is greater than 'xstate_size':
    65		 */
    66		__u32				xstate_size;
    67	
    68		/* For future use: */
    69		__u32				padding[7];
    70	};
    71	
    72	/*
    73	 * As documented in the iBCS2 standard:
    74	 *
    75	 * The first part of "struct _fpstate" is just the normal i387 hardware setup,
    76	 * the extra "status" word is used to save the coprocessor status word before
    77	 * entering the handler.
    78	 *
    79	 * The FPU state data structure has had to grow to accommodate the extended FPU
    80	 * state required by the Streaming SIMD Extensions.  There is no documented
    81	 * standard to accomplish this at the moment.
    82	 */
    83	
    84	/* 10-byte legacy floating point register: */
    85	struct _fpreg {
    86		__u16				significand[4];
    87		__u16				exponent;
    88	};
    89	
    90	/* 16-byte floating point register: */
    91	struct _fpxreg {
    92		__u16				significand[4];
    93		__u16				exponent;
    94		__u16				padding[3];
    95	};
    96	
    97	/* 16-byte XMM register: */
    98	struct _xmmreg {
    99		__u32				element[4];
   100	};
   101	
   102	#define X86_FXSR_MAGIC			0x0000
   103	
   104	/*
   105	 * The 32-bit FPU frame:
   106	 */
   107	struct _fpstate_32 {
   108		/* Legacy FPU environment: */
   109		__u32				cw;
   110		__u32				sw;
   111		__u32				tag;
   112		__u32				ipoff;
   113		__u32				cssel;
   114		__u32				dataoff;
   115		__u32				datasel;
   116		struct _fpreg			_st[8];
   117		__u16				status;
   118		__u16				magic;		/* 0xffff: regular FPU data only */
   119								/* 0x0000: FXSR FPU data */
   120	
   121		/* FXSR FPU environment */
   122		__u32				_fxsr_env[6];	/* FXSR FPU env is ignored */
   123		__u32				mxcsr;
   124		__u32				reserved;
   125		struct _fpxreg			_fxsr_st[8];	/* FXSR FPU reg data is ignored */
   126		struct _xmmreg			_xmm[8];	/* First 8 XMM registers */
   127		union {
   128			__u32			padding1[44];	/* Second 8 XMM registers plus padding */
   129			__u32			padding[44];	/* Alias name for old user-space */
   130		};
   131	
   132		union {
   133			__u32			padding2[12];
   134			struct _fpx_sw_bytes	sw_reserved;	/* Potential extended state is encoded here */
   135		};
   136	};
   137	
   138	/*
   139	 * The 64-bit FPU frame. (FXSAVE format and later)
   140	 *
   141	 * Note1: If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then the structure is
   142	 *        larger: 'struct _xstate'. Note that 'struct _xstate' embeds
   143	 *        'struct _fpstate' so that you can always assume the _fpstate portion
   144	 *        exists so that you can check the magic value.
   145	 *
   146	 * Note2: Reserved fields may someday contain valuable data. Always
   147	 *	  save/restore them when you change signal frames.
   148	 */
   149	struct _fpstate_64 {
   150		__u16				cwd;
   151		__u16				swd;
   152		/* Note this is not the same as the 32-bit/x87/FSAVE twd: */
   153		__u16				twd;
   154		__u16				fop;
   155		__u64				rip;
   156		__u64				rdp;
   157		__u32				mxcsr;
   158		__u32				mxcsr_mask;
   159		__u32				st_space[32];	/*  8x  FP registers, 16 bytes each */
   160		__u32				xmm_space[64];	/* 16x XMM registers, 16 bytes each */
   161		__u32				reserved2[12];
   162		union {
   163			__u32			reserved3[12];
   164			struct _fpx_sw_bytes	sw_reserved;	/* Potential extended state is encoded here */
   165		};
   166	};
   167	
   168	#ifdef __i386__
   169	# define _fpstate _fpstate_32
   170	#else
   171	# define _fpstate _fpstate_64
   172	#endif
   173	
   174	struct _header {
   175		__u64				xfeatures;
   176		__u64				reserved1[2];
   177		__u64				reserved2[5];
   178	};
   179	
   180	struct _ymmh_state {
   181		/* 16x YMM registers, 16 bytes each: */
   182		__u32				ymmh_space[64];
   183	};
   184	
   185	/*
   186	 * Extended state pointed to by sigcontext::fpstate.
   187	 *
   188	 * In addition to the fpstate, information encoded in _xstate::xstate_hdr
   189	 * indicates the presence of other extended state information supported
   190	 * by the CPU and kernel:
   191	 */
   192	struct _xstate {
   193		struct _fpstate			fpstate;
   194		struct _header			xstate_hdr;
   195		struct _ymmh_state		ymmh;
   196		/* New processor state extensions go here: */
   197	};
   198	
   199	/*
   200	 * The 32-bit signal frame:
   201	 */
   202	struct sigcontext_32 {
   203		__u16				gs, __gsh;
   204		__u16				fs, __fsh;
   205		__u16				es, __esh;
   206		__u16				ds, __dsh;
   207		__u32				di;
   208		__u32				si;
   209		__u32				bp;
   210		__u32				sp;
   211		__u32				bx;
   212		__u32				dx;
   213		__u32				cx;
   214		__u32				ax;
   215		__u32				trapno;
   216		__u32				err;
   217		__u32				ip;
   218		__u16				cs, __csh;
   219		__u32				flags;
   220		__u32				sp_at_signal;
   221		__u16				ss, __ssh;
   222	
   223		/*
   224		 * fpstate is really (struct _fpstate *) or (struct _xstate *)
   225		 * depending on the FP_XSTATE_MAGIC1 encoded in the SW reserved
   226		 * bytes of (struct _fpstate) and FP_XSTATE_MAGIC2 present at the end
   227		 * of extended memory layout. See comments at the definition of
   228		 * (struct _fpx_sw_bytes)
   229		 */
   230		__u32				fpstate; /* Zero when no FPU/extended context */
   231		__u32				oldmask;
   232		__u32				cr2;
   233	};
   234	
   235	/*
   236	 * The 64-bit signal frame:
   237	 */
   238	struct sigcontext_64 {
   239		__u64				r8;
   240		__u64				r9;
   241		__u64				r10;
   242		__u64				r11;
   243		__u64				r12;
   244		__u64				r13;
   245		__u64				r14;
   246		__u64				r15;
   247		__u64				di;
   248		__u64				si;
   249		__u64				bp;
   250		__u64				bx;
   251		__u64				dx;
   252		__u64				ax;
   253		__u64				cx;
   254		__u64				sp;
   255		__u64				ip;
   256		__u64				flags;
   257		__u16				cs;
   258		__u16				gs;
   259		__u16				fs;
   260		__u16				ss;
   261		__u64				err;
   262		__u64				trapno;
   263		__u64				oldmask;
   264		__u64				cr2;
   265	
   266		/*
   267		 * fpstate is really (struct _fpstate *) or (struct _xstate *)
   268		 * depending on the FP_XSTATE_MAGIC1 encoded in the SW reserved
   269		 * bytes of (struct _fpstate) and FP_XSTATE_MAGIC2 present at the end
   270		 * of extended memory layout. See comments at the definition of
   271		 * (struct _fpx_sw_bytes)
   272		 */
   273		__u64				fpstate; /* Zero when no FPU/extended context */
   274		__u64				reserved1[8];
   275	};
   276	
   277	/*
   278	 * Create the real 'struct sigcontext' type:
   279	 */
   280	
   281	/*
   282	 * The old user-space sigcontext definition, just in case user-space still
   283	 * relies on it. The kernel definition (in asm/sigcontext.h) has unified
   284	 * field names but otherwise the same layout.
   285	 */
   286	
   287	#define _fpstate_ia32			_fpstate_32
   288	#define sigcontext_ia32			sigcontext_32
   289	
   290	
   291	# ifdef __i386__
   292	struct sigcontext {
   293		__u16				gs, __gsh;
   294		__u16				fs, __fsh;
   295		__u16				es, __esh;
   296		__u16				ds, __dsh;
   297		__u32				edi;
   298		__u32				esi;
   299		__u32				ebp;
   300		__u32				esp;
   301		__u32				ebx;
   302		__u32				edx;
   303		__u32				ecx;
   304		__u32				eax;
   305		__u32				trapno;
   306		__u32				err;
   307		__u32				eip;
   308		__u16				cs, __csh;
   309		__u32				eflags;
   310		__u32				esp_at_signal;
   311		__u16				ss, __ssh;
   312		struct _fpstate 	*fpstate;
   313		__u32				oldmask;
   314		__u32				cr2;
   315	};
   316	# else /* __x86_64__: */
   317	struct sigcontext {
   318		__u64				r8;
   319		__u64				r9;
   320		__u64				r10;
   321		__u64				r11;
   322		__u64				r12;
   323		__u64				r13;
   324		__u64				r14;
   325		__u64				r15;
   326		__u64				rdi;
   327		__u64				rsi;
   328		__u64				rbp;
   329		__u64				rbx;
   330		__u64				rdx;
   331		__u64				rax;
   332		__u64				rcx;
   333		__u64				rsp;
   334		__u64				rip;
   335		__u64				eflags;		/* RFLAGS */
   336		__u16				cs;
   337	
   338		/*
   339		 * Prior to 2.5.64 ("[PATCH] x86-64 updates for 2.5.64-bk3"),
   340		 * Linux saved and restored fs and gs in these slots.  This
   341		 * was counterproductive, as fsbase and gsbase were never
   342		 * saved, so arch_prctl was presumably unreliable.
   343		 *
   344		 * These slots should never be reused without extreme caution:
   345		 *
   346		 *  - Some DOSEMU versions stash fs and gs in these slots manually,
   347		 *    thus overwriting anything the kernel expects to be preserved
   348		 *    in these slots.
   349		 *
   350		 *  - If these slots are ever needed for any other purpose,
   351		 *    there is some risk that very old 64-bit binaries could get
   352		 *    confused.  I doubt that many such binaries still work,
   353		 *    though, since the same patch in 2.5.64 also removed the
   354		 *    64-bit set_thread_area syscall, so it appears that there
   355		 *    is no TLS API beyond modify_ldt that works in both pre-
   356		 *    and post-2.5.64 kernels.
   357		 *
   358		 * If the kernel ever adds explicit fs, gs, fsbase, and gsbase
   359		 * save/restore, it will most likely need to be opt-in and use
   360		 * different context slots.
   361		 */
   362		__u16				gs;
   363		__u16				fs;
   364		union {
   365			__u16			ss;	/* If UC_SIGCONTEXT_SS */
   366			__u16			__pad0;	/* Alias name for old (!UC_SIGCONTEXT_SS) user-space */
   367		};
   368		__u64				err;
   369		__u64				trapno;
   370		__u64				oldmask;
   371		__u64				cr2;
   372		struct _fpstate 	*fpstate;	/* Zero when no FPU context */
   373	#  ifdef __ILP32__
   374		__u32				__fpstate_pad;
   375	#  endif
   376		__u64				reserved1[8];
   377	};
   378	# endif /* __x86_64__ */
   379	
   380	#endif /* _ASM_X86_SIGCONTEXT_H */