/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef _UAPI_ASM_X86_SIGCONTEXT_H
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#define _UAPI_ASM_X86_SIGCONTEXT_H
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/*
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* Linux signal context definitions. The sigcontext includes a complex
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* hierarchy of CPU and FPU state, available to user-space (on the stack) when
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* a signal handler is executed.
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*
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* As over the years this ABI grew from its very simple roots towards
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* supporting more and more CPU state organically, some of the details (which
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* were rather clever hacks back in the days) became a bit quirky by today.
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*
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* The current ABI includes flexible provisions for future extensions, so we
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* won't have to grow new quirks for quite some time. Promise!
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*/
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#include <linux/compiler.h>
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#include <linux/types.h>
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#define FP_XSTATE_MAGIC1 0x46505853U
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#define FP_XSTATE_MAGIC2 0x46505845U
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#define FP_XSTATE_MAGIC2_SIZE sizeof(FP_XSTATE_MAGIC2)
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/*
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* Bytes 464..511 in the current 512-byte layout of the FXSAVE/FXRSTOR frame
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* are reserved for SW usage. On CPUs supporting XSAVE/XRSTOR, these bytes are
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* used to extend the fpstate pointer in the sigcontext, which now includes the
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* extended state information along with fpstate information.
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*
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* If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then there's a
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* sw_reserved.extended_size bytes large extended context area present. (The
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* last 32-bit word of this extended area (at the
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* fpstate+extended_size-FP_XSTATE_MAGIC2_SIZE address) is set to
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* FP_XSTATE_MAGIC2 so that you can sanity check your size calculations.)
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*
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* This extended area typically grows with newer CPUs that have larger and
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* larger XSAVE areas.
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*/
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struct _fpx_sw_bytes {
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/*
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* If set to FP_XSTATE_MAGIC1 then this is an xstate context.
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* 0 if a legacy frame.
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*/
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__u32 magic1;
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/*
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* Total size of the fpstate area:
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*
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* - if magic1 == 0 then it's sizeof(struct _fpstate)
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* - if magic1 == FP_XSTATE_MAGIC1 then it's sizeof(struct _xstate)
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* plus extensions (if any)
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*/
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__u32 extended_size;
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/*
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* Feature bit mask (including FP/SSE/extended state) that is present
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* in the memory layout:
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*/
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__u64 xfeatures;
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/*
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* Actual XSAVE state size, based on the xfeatures saved in the layout.
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* 'extended_size' is greater than 'xstate_size':
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*/
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__u32 xstate_size;
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/* For future use: */
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__u32 padding[7];
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};
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/*
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* As documented in the iBCS2 standard:
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*
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* The first part of "struct _fpstate" is just the normal i387 hardware setup,
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* the extra "status" word is used to save the coprocessor status word before
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* entering the handler.
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*
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* The FPU state data structure has had to grow to accommodate the extended FPU
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* state required by the Streaming SIMD Extensions. There is no documented
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* standard to accomplish this at the moment.
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*/
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/* 10-byte legacy floating point register: */
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struct _fpreg {
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__u16 significand[4];
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__u16 exponent;
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};
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/* 16-byte floating point register: */
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struct _fpxreg {
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__u16 significand[4];
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__u16 exponent;
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__u16 padding[3];
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};
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/* 16-byte XMM register: */
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struct _xmmreg {
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__u32 element[4];
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};
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#define X86_FXSR_MAGIC 0x0000
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/*
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* The 32-bit FPU frame:
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*/
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struct _fpstate_32 {
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/* Legacy FPU environment: */
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__u32 cw;
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__u32 sw;
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__u32 tag;
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__u32 ipoff;
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__u32 cssel;
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__u32 dataoff;
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__u32 datasel;
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struct _fpreg _st[8];
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__u16 status;
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__u16 magic; /* 0xffff: regular FPU data only */
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/* 0x0000: FXSR FPU data */
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/* FXSR FPU environment */
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__u32 _fxsr_env[6]; /* FXSR FPU env is ignored */
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__u32 mxcsr;
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__u32 reserved;
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struct _fpxreg _fxsr_st[8]; /* FXSR FPU reg data is ignored */
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struct _xmmreg _xmm[8]; /* First 8 XMM registers */
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union {
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__u32 padding1[44]; /* Second 8 XMM registers plus padding */
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__u32 padding[44]; /* Alias name for old user-space */
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};
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union {
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__u32 padding2[12];
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struct _fpx_sw_bytes sw_reserved; /* Potential extended state is encoded here */
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};
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};
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/*
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* The 64-bit FPU frame. (FXSAVE format and later)
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*
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* Note1: If sw_reserved.magic1 == FP_XSTATE_MAGIC1 then the structure is
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* larger: 'struct _xstate'. Note that 'struct _xstate' embedds
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* 'struct _fpstate' so that you can always assume the _fpstate portion
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* exists so that you can check the magic value.
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*
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* Note2: Reserved fields may someday contain valuable data. Always
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* save/restore them when you change signal frames.
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*/
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struct _fpstate_64 {
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__u16 cwd;
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__u16 swd;
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/* Note this is not the same as the 32-bit/x87/FSAVE twd: */
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__u16 twd;
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__u16 fop;
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__u64 rip;
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__u64 rdp;
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__u32 mxcsr;
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__u32 mxcsr_mask;
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__u32 st_space[32]; /* 8x FP registers, 16 bytes each */
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__u32 xmm_space[64]; /* 16x XMM registers, 16 bytes each */
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__u32 reserved2[12];
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union {
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__u32 reserved3[12];
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struct _fpx_sw_bytes sw_reserved; /* Potential extended state is encoded here */
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};
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};
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#ifdef __i386__
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# define _fpstate _fpstate_32
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#else
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# define _fpstate _fpstate_64
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#endif
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struct _header {
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__u64 xfeatures;
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__u64 reserved1[2];
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__u64 reserved2[5];
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};
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struct _ymmh_state {
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/* 16x YMM registers, 16 bytes each: */
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__u32 ymmh_space[64];
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};
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/*
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* Extended state pointed to by sigcontext::fpstate.
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*
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* In addition to the fpstate, information encoded in _xstate::xstate_hdr
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* indicates the presence of other extended state information supported
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* by the CPU and kernel:
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*/
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struct _xstate {
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struct _fpstate fpstate;
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struct _header xstate_hdr;
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struct _ymmh_state ymmh;
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/* New processor state extensions go here: */
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};
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/*
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* The 32-bit signal frame:
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*/
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struct sigcontext_32 {
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__u16 gs, __gsh;
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__u16 fs, __fsh;
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__u16 es, __esh;
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__u16 ds, __dsh;
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__u32 di;
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__u32 si;
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__u32 bp;
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__u32 sp;
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__u32 bx;
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__u32 dx;
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__u32 cx;
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__u32 ax;
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__u32 trapno;
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__u32 err;
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__u32 ip;
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__u16 cs, __csh;
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__u32 flags;
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__u32 sp_at_signal;
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__u16 ss, __ssh;
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/*
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* fpstate is really (struct _fpstate *) or (struct _xstate *)
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* depending on the FP_XSTATE_MAGIC1 encoded in the SW reserved
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* bytes of (struct _fpstate) and FP_XSTATE_MAGIC2 present at the end
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* of extended memory layout. See comments at the definition of
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* (struct _fpx_sw_bytes)
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*/
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__u32 fpstate; /* Zero when no FPU/extended context */
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__u32 oldmask;
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__u32 cr2;
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};
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/*
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* The 64-bit signal frame:
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*/
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struct sigcontext_64 {
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__u64 r8;
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__u64 r9;
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__u64 r10;
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__u64 r11;
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__u64 r12;
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__u64 r13;
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__u64 r14;
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__u64 r15;
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__u64 di;
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__u64 si;
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__u64 bp;
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__u64 bx;
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__u64 dx;
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__u64 ax;
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__u64 cx;
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__u64 sp;
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__u64 ip;
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__u64 flags;
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__u16 cs;
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__u16 gs;
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__u16 fs;
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__u16 ss;
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__u64 err;
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__u64 trapno;
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__u64 oldmask;
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__u64 cr2;
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/*
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* fpstate is really (struct _fpstate *) or (struct _xstate *)
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* depending on the FP_XSTATE_MAGIC1 encoded in the SW reserved
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* bytes of (struct _fpstate) and FP_XSTATE_MAGIC2 present at the end
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* of extended memory layout. See comments at the definition of
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* (struct _fpx_sw_bytes)
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*/
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__u64 fpstate; /* Zero when no FPU/extended context */
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__u64 reserved1[8];
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};
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/*
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* Create the real 'struct sigcontext' type:
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*/
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#ifdef __KERNEL__
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# ifdef __i386__
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# define sigcontext sigcontext_32
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# else
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# define sigcontext sigcontext_64
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# endif
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#endif
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/*
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* The old user-space sigcontext definition, just in case user-space still
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* relies on it. The kernel definition (in asm/sigcontext.h) has unified
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* field names but otherwise the same layout.
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*/
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#ifndef __KERNEL__
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#define _fpstate_ia32 _fpstate_32
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#define sigcontext_ia32 sigcontext_32
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# ifdef __i386__
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struct sigcontext {
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__u16 gs, __gsh;
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__u16 fs, __fsh;
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__u16 es, __esh;
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__u16 ds, __dsh;
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__u32 edi;
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__u32 esi;
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__u32 ebp;
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__u32 esp;
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__u32 ebx;
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__u32 edx;
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__u32 ecx;
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__u32 eax;
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__u32 trapno;
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__u32 err;
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__u32 eip;
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__u16 cs, __csh;
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__u32 eflags;
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__u32 esp_at_signal;
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__u16 ss, __ssh;
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struct _fpstate __user *fpstate;
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__u32 oldmask;
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__u32 cr2;
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};
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# else /* __x86_64__: */
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struct sigcontext {
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__u64 r8;
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__u64 r9;
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__u64 r10;
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__u64 r11;
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__u64 r12;
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__u64 r13;
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__u64 r14;
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__u64 r15;
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__u64 rdi;
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__u64 rsi;
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__u64 rbp;
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__u64 rbx;
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__u64 rdx;
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__u64 rax;
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__u64 rcx;
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__u64 rsp;
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__u64 rip;
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__u64 eflags; /* RFLAGS */
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__u16 cs;
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/*
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* Prior to 2.5.64 ("[PATCH] x86-64 updates for 2.5.64-bk3"),
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* Linux saved and restored fs and gs in these slots. This
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* was counterproductive, as fsbase and gsbase were never
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* saved, so arch_prctl was presumably unreliable.
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*
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* These slots should never be reused without extreme caution:
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*
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* - Some DOSEMU versions stash fs and gs in these slots manually,
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* thus overwriting anything the kernel expects to be preserved
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* in these slots.
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*
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* - If these slots are ever needed for any other purpose,
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* there is some risk that very old 64-bit binaries could get
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* confused. I doubt that many such binaries still work,
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* though, since the same patch in 2.5.64 also removed the
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* 64-bit set_thread_area syscall, so it appears that there
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* is no TLS API beyond modify_ldt that works in both pre-
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* and post-2.5.64 kernels.
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*
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* If the kernel ever adds explicit fs, gs, fsbase, and gsbase
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* save/restore, it will most likely need to be opt-in and use
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* different context slots.
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*/
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__u16 gs;
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__u16 fs;
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union {
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__u16 ss; /* If UC_SIGCONTEXT_SS */
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__u16 __pad0; /* Alias name for old (!UC_SIGCONTEXT_SS) user-space */
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};
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__u64 err;
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__u64 trapno;
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__u64 oldmask;
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__u64 cr2;
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struct _fpstate __user *fpstate; /* Zero when no FPU context */
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# ifdef __ILP32__
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__u32 __fpstate_pad;
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# endif
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__u64 reserved1[8];
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};
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# endif /* __x86_64__ */
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#endif /* !__KERNEL__ */
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#endif /* _UAPI_ASM_X86_SIGCONTEXT_H */
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