diff options
| -rw-r--r-- | arch/x86/include/uapi/asm/sigcontext.h | 330 |
1 files changed, 182 insertions, 148 deletions
diff --git a/arch/x86/include/uapi/asm/sigcontext.h b/arch/x86/include/uapi/asm/sigcontext.h index 40836a9a7250..f89b2f1abe7c 100644 --- a/arch/x86/include/uapi/asm/sigcontext.h +++ b/arch/x86/include/uapi/asm/sigcontext.h @@ -1,221 +1,255 @@ #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) +#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 + * 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. * - * 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. + * 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 { - __u32 magic1; /* FP_XSTATE_MAGIC1 */ - __u32 extended_size; /* total size of the layout referred by - * fpstate pointer in the sigcontext. - */ - __u64 xfeatures; - /* 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. */ + /* 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]; }; #ifdef __i386__ /* - * As documented in the iBCS2 standard.. + * 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. */ + +/* 10-byte legacy floating point register: */ struct _fpreg { - unsigned short significand[4]; - unsigned short exponent; + unsigned short significand[4]; + unsigned short exponent; }; +/* 16-byte floating point register: */ struct _fpxreg { - unsigned short significand[4]; - unsigned short exponent; - unsigned short padding[3]; + unsigned short significand[4]; + unsigned short exponent; + unsigned short padding[3]; }; +/* 16-byte XMM register: */ struct _xmmreg { - unsigned long element[4]; + unsigned long element[4]; }; +#define X86_FXSR_MAGIC 0x0000 + 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 */ + /* Legacy 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 */ + /* 0x0000: FXSR FPU data */ /* 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]; + 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]; /* First 8 XMM registers */ + unsigned long padding1[44]; /* Second 8 XMM registers plus padding */ union { - unsigned long padding2[12]; - struct _fpx_sw_bytes sw_reserved; /* represents the extended - * state info */ + unsigned long padding2[12]; + struct _fpx_sw_bytes sw_reserved; /* Potential extended state is encoded here */ }; }; -#define X86_FXSR_MAGIC 0x0000 - -#ifndef __KERNEL__ +# ifndef __KERNEL__ /* * 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 __user *fpstate; - unsigned long oldmask; - unsigned long cr2; + 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 __user *fpstate; + unsigned long oldmask; + unsigned long cr2; }; -#endif /* !__KERNEL__ */ +# endif /* !__KERNEL__ */ -#else /* __i386__ */ +#else /* __x86_64__: */ -/* FXSAVE frame */ -/* Note: reserved1/2 may someday contain valuable data. Always save/restore - them when you change signal frames. */ +/* + * The FXSAVE frame. + * + * 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 { - __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]; + __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; /* represents the extended - * state information */ + __u32 reserved3[12]; + struct _fpx_sw_bytes sw_reserved; /* Potential extended state is encoded here */ }; }; -#ifndef __KERNEL__ +# ifndef __KERNEL__ /* * 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 __user *fpstate; /* zero when no FPU context */ -#ifdef __ILP32__ - __u32 __fpstate_pad; -#endif - __u64 reserved1[8]; + __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 __user *fpstate; /* Zero when no FPU context */ +# ifdef __ILP32__ + __u32 __fpstate_pad; +# endif + __u64 reserved1[8]; }; -#endif /* !__KERNEL__ */ +# endif /* !__KERNEL__ */ -#endif /* !__i386__ */ +#endif /* __x86_64__ */ struct _header { - __u64 xfeatures; - __u64 reserved1[2]; - __u64 reserved2[5]; + __u64 xfeatures; + __u64 reserved1[2]; + __u64 reserved2[5]; }; struct _ymmh_state { - /* 16 * 16 bytes for each YMMH-reg */ - __u32 ymmh_space[64]; + /* 16x YMM registers, 16 bytes each: */ + __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. + * 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 */ + struct _fpstate fpstate; + struct _header xstate_hdr; + struct _ymmh_state ymmh; + /* New processor state extensions go here: */ }; #endif /* _UAPI_ASM_X86_SIGCONTEXT_H */ |