arch/x86/include/asm/desc_defs.h

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

File Facts

System
Linux kernel
Corpus path
arch/x86/include/asm/desc_defs.h
Extension
.h
Size
4970 bytes
Lines
198
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 desc_struct {
	u16	limit0;
	u16	base0;
	u16	base1: 8, type: 4, s: 1, dpl: 2, p: 1;
	u16	limit1: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
} __attribute__((packed));

#define GDT_ENTRY_INIT(flags, base, limit)			\
	{							\
		.limit0		= ((limit) >>  0) & 0xFFFF,	\
		.limit1		= ((limit) >> 16) & 0x000F,	\
		.base0		= ((base)  >>  0) & 0xFFFF,	\
		.base1		= ((base)  >> 16) & 0x00FF,	\
		.base2		= ((base)  >> 24) & 0x00FF,	\
		.type		= ((flags) >>  0) & 0x000F,	\
		.s		= ((flags) >>  4) & 0x0001,	\
		.dpl		= ((flags) >>  5) & 0x0003,	\
		.p		= ((flags) >>  7) & 0x0001,	\
		.avl		= ((flags) >> 12) & 0x0001,	\
		.l		= ((flags) >> 13) & 0x0001,	\
		.d		= ((flags) >> 14) & 0x0001,	\
		.g		= ((flags) >> 15) & 0x0001,	\
	}

enum {
	GATE_INTERRUPT = 0xE,
	GATE_TRAP = 0xF,
	GATE_CALL = 0xC,
	GATE_TASK = 0x5,
};

enum {
	DESC_TSS = 0x9,
	DESC_LDT = 0x2,
	DESCTYPE_S = 0x10,	/* !system */
};

/* LDT or TSS descriptor in the GDT. */
struct ldttss_desc {
	u16	limit0;
	u16	base0;

	u16	base1 : 8, type : 5, dpl : 2, p : 1;
	u16	limit1 : 4, zero0 : 3, g : 1, base2 : 8;
#ifdef CONFIG_X86_64
	u32	base3;
	u32	zero1;
#endif
} __attribute__((packed));

typedef struct ldttss_desc ldt_desc;
typedef struct ldttss_desc tss_desc;

struct idt_bits {
	u16		ist	: 3,
			zero	: 5,
			type	: 5,
			dpl	: 2,
			p	: 1;
} __attribute__((packed));

struct idt_data {
	unsigned int	vector;
	unsigned int	segment;
	struct idt_bits	bits;
	const void	*addr;
};

struct gate_struct {
	u16		offset_low;
	u16		segment;
	struct idt_bits	bits;
	u16		offset_middle;
#ifdef CONFIG_X86_64
	u32		offset_high;
	u32		reserved;
#endif
} __attribute__((packed));

typedef struct gate_struct gate_desc;

#ifndef _SETUP
static __always_inline unsigned long gate_offset(const gate_desc *g)
{
#ifdef CONFIG_X86_64
	return g->offset_low | ((unsigned long)g->offset_middle << 16) |
		((unsigned long) g->offset_high << 32);
#else
	return g->offset_low | ((unsigned long)g->offset_middle << 16);
#endif

Annotation

Implementation Notes