arch/x86/include/uapi/asm/sigcontext.h

Source file repositories/reference/linux-study-clean/arch/x86/include/uapi/asm/sigcontext.h

File Facts

System
Linux kernel
Corpus path
arch/x86/include/uapi/asm/sigcontext.h
Extension
.h
Size
9950 bytes
Lines
390
Domain
Architecture Layer
Bucket
arch/x86
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

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 */

Annotation

Implementation Notes