arch/x86/lib/insn.c

Source file repositories/reference/linux-study-clean/arch/x86/lib/insn.c

File Facts

System
Linux kernel
Corpus path
arch/x86/lib/insn.c
Extension
.c
Size
19191 bytes
Lines
793
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

if (inat_is_address_size_prefix(attr)) {
			/* address size switches 2/4 or 4/8 */
			if (insn->x86_64)
				insn->addr_bytes ^= 12;
			else
				insn->addr_bytes ^= 6;
		} else if (inat_is_operand_size_prefix(attr)) {
			/* oprand size switches 2/4 */
			insn->opnd_bytes ^= 6;
		}
found:
		prefixes->nbytes++;
		insn->next_byte++;
		lb = b;
		b = peek_next(insn_byte_t, insn);
		attr = inat_get_opcode_attribute(b);
	}
	/* Set the last prefix */
	if (lb && lb != insn->prefixes.bytes[3]) {
		if (unlikely(insn->prefixes.bytes[3])) {
			/* Swap the last prefix */
			b = insn->prefixes.bytes[3];
			for (i = 0; i < nb; i++)
				if (prefixes->bytes[i] == lb)
					insn_set_byte(prefixes, i, b);
		}
		insn_set_byte(&insn->prefixes, 3, lb);
	}

	/* Decode REX prefix */
	if (insn->x86_64) {
		b = peek_next(insn_byte_t, insn);
		attr = inat_get_opcode_attribute(b);
		if (inat_is_rex_prefix(attr)) {
			insn_field_set(&insn->rex_prefix, b, 1);
			insn->next_byte++;
			if (X86_REX_W(b))
				/* REX.W overrides opnd_size */
				insn->opnd_bytes = 8;
		} else if (inat_is_rex2_prefix(attr)) {
			insn_set_byte(&insn->rex_prefix, 0, b);
			b = peek_nbyte_next(insn_byte_t, insn, 1);
			insn_set_byte(&insn->rex_prefix, 1, b);
			insn->rex_prefix.nbytes = 2;
			insn->next_byte += 2;
			if (X86_REX_W(b))
				/* REX.W overrides opnd_size */
				insn->opnd_bytes = 8;
			insn->rex_prefix.got = 1;
			goto vex_end;
		}
	}
	insn->rex_prefix.got = 1;

	/* Decode VEX/XOP prefix */
	b = peek_next(insn_byte_t, insn);
	if (inat_is_vex_prefix(attr) || inat_is_xop_prefix(attr)) {
		insn_byte_t b2 = peek_nbyte_next(insn_byte_t, insn, 1);

		if (inat_is_xop_prefix(attr) && X86_MODRM_REG(b2) == 0) {
			/* Grp1A.0 is always POP Ev */
			goto vex_end;
		} else if (!insn->x86_64) {
			/*
			 * In 32-bits mode, if the [7:6] bits (mod bits of
			 * ModRM) on the second byte are not 11b, it is
			 * LDS or LES or BOUND.
			 */
			if (X86_MODRM_MOD(b2) != 3)
				goto vex_end;
		}
		insn_set_byte(&insn->vex_prefix, 0, b);
		insn_set_byte(&insn->vex_prefix, 1, b2);
		if (inat_is_evex_prefix(attr)) {
			b2 = peek_nbyte_next(insn_byte_t, insn, 2);
			insn_set_byte(&insn->vex_prefix, 2, b2);
			b2 = peek_nbyte_next(insn_byte_t, insn, 3);
			insn_set_byte(&insn->vex_prefix, 3, b2);
			insn->vex_prefix.nbytes = 4;
			insn->next_byte += 4;
			if (insn->x86_64 && X86_VEX_W(b2))
				/* VEX.W overrides opnd_size */
				insn->opnd_bytes = 8;
		} else if (inat_is_vex3_prefix(attr) || inat_is_xop_prefix(attr)) {
			b2 = peek_nbyte_next(insn_byte_t, insn, 2);
			insn_set_byte(&insn->vex_prefix, 2, b2);
			insn->vex_prefix.nbytes = 3;
			insn->next_byte += 3;
			if (insn->x86_64 && X86_VEX_W(b2))
				/* VEX.W/XOP.W overrides opnd_size */

Annotation

Implementation Notes