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Diffstat (limited to 'arch/x86/include/uapi/asm/sigcontext.h')
| -rw-r--r-- | arch/x86/include/uapi/asm/sigcontext.h | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/sigcontext.h b/arch/x86/include/uapi/asm/sigcontext.h new file mode 100644 index 000000000..d0d9b331d --- /dev/null +++ b/arch/x86/include/uapi/asm/sigcontext.h @@ -0,0 +1,389 @@ +/* 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' embeds + * '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 */ |