This file is indexed.

/usr/include/x86_64-linux-gnu/asm/sigcontext.h is in linux-libc-dev 3.13.0-24.46.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
#ifndef _ASM_X86_SIGCONTEXT_H
#define _ASM_X86_SIGCONTEXT_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 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..
 *
 * 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.
 *
 * Pentium III FXSR, SSE support
 *	Gareth Hughes <gareth@valinux.com>, May 2000
 *
 * 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.
 */
struct _fpreg {
	unsigned short significand[4];
	unsigned short exponent;
};

struct _fpxreg {
	unsigned short significand[4];
	unsigned short exponent;
	unsigned short padding[3];
};

struct _xmmreg {
	unsigned long element[4];
};

struct _fpstate {
	/* Regular FPU environment */
	unsigned long	cw;
	unsigned long	sw;
	unsigned long	tag;
	unsigned long	ipoff;
	unsigned long	cssel;
	unsigned long	dataoff;
	unsigned long	datasel;
	struct _fpreg	_st[8];
	unsigned short	status;
	unsigned short	magic;		/* 0xffff = regular FPU data only */

	/* FXSR FPU environment */
	unsigned long	_fxsr_env[6];	/* FXSR FPU env is ignored */
	unsigned long	mxcsr;
	unsigned long	reserved;
	struct _fpxreg	_fxsr_st[8];	/* FXSR FPU reg data is ignored */
	struct _xmmreg	_xmm[8];
	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

/*
 * User-space might still rely on the old definition:
 */
struct sigcontext {
	unsigned short gs, __gsh;
	unsigned short fs, __fsh;
	unsigned short es, __esh;
	unsigned short ds, __dsh;
	unsigned long edi;
	unsigned long esi;
	unsigned long ebp;
	unsigned long esp;
	unsigned long ebx;
	unsigned long edx;
	unsigned long ecx;
	unsigned long eax;
	unsigned long trapno;
	unsigned long err;
	unsigned long eip;
	unsigned short cs, __csh;
	unsigned long eflags;
	unsigned long esp_at_signal;
	unsigned short ss, __ssh;
	struct _fpstate *fpstate;
	unsigned long oldmask;
	unsigned long cr2;
};

#else /* __i386__ */

/* FXSAVE frame */
/* Note: reserved1/2 may someday contain valuable data. Always save/restore
   them when you change signal frames. */
struct _fpstate {
	__u16	cwd;
	__u16	swd;
	__u16	twd;		/* Note this is not the same as the
				   32bit/x87/FSAVE twd */
	__u16	fop;
	__u64	rip;
	__u64	rdp;
	__u32	mxcsr;
	__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[12];
	union {
		__u32	reserved3[12];
		struct _fpx_sw_bytes sw_reserved; /* represents the extended
						   * state information */
	};
};

/*
 * User-space might still rely on the old definition:
 */
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;
	__u16 gs;
	__u16 fs;
	__u16 __pad0;
	__u64 err;
	__u64 trapno;
	__u64 oldmask;
	__u64 cr2;
	struct _fpstate *fpstate;	/* zero when no FPU context */
#ifdef __ILP32__
	__u32 __fpstate_pad;
#endif
	__u64 reserved1[8];
};

#endif /* !__i386__ */

struct _xsave_hdr {
	__u64 xstate_bv;
	__u64 reserved1[2];
	__u64 reserved2[5];
};

struct _ymmh_state {
	/* 16 * 16 bytes for each YMMH-reg */
	__u32 ymmh_space[64];
};

/*
 * 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;
	struct _ymmh_state ymmh;
	/* new processor state extensions go here */
};

#endif /* _ASM_X86_SIGCONTEXT_H */