Commit 36d92e43 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

objtool,x86: More ModRM sugar 



Better helpers to decode ModRM.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/YCZB/ljatFXqQbm8@hirez.programming.kicks-ass.net
parent 961d83b9

tools/objtool/arch/x86/decode.c

+17 −11
Original line number Diff line number Diff line
@@ -82,15 +82,21 @@ unsigned long arch_jump_destination(struct instruction *insn) 
 * 01 |  [r/m + d8]    |[S+d]|   [r/m + d8]  |

 * 10 |  [r/m + d32]   |[S+D]|   [r/m + d32] |

 * 11 |                   r/ m               |

 *

 */



#define mod_is_mem()	(modrm_mod != 3)

#define mod_is_reg()	(modrm_mod == 3)



#define is_RIP()   ((modrm_rm & 7) == CFI_BP && modrm_mod == 0)

#define have_SIB() ((modrm_rm & 7) == CFI_SP && modrm_mod != 3)

#define have_SIB() ((modrm_rm & 7) == CFI_SP && mod_is_mem())



#define rm_is(reg) (have_SIB() ? \

		    sib_base == (reg) && sib_index == CFI_SP : \

		    modrm_rm == (reg))



#define rm_is_mem(reg)	(mod_is_mem() && !is_RIP() && rm_is(reg))

#define rm_is_reg(reg)	(mod_is_reg() && modrm_rm == (reg))



int arch_decode_instruction(const struct elf *elf, const struct section *sec,

			    unsigned long offset, unsigned int maxlen,

			    unsigned int *len, enum insn_type *type,
@@ -154,7 +160,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 


	case 0x1:

	case 0x29:

		if (rex_w && modrm_mod == 3 && modrm_rm == CFI_SP) {

		if (rex_w && rm_is_reg(CFI_SP)) {



			/* add/sub reg, %rsp */

			ADD_OP(op) {
@@ -219,7 +225,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
			break;



		/* %rsp target only */

		if (!(modrm_mod == 3 && modrm_rm == CFI_SP))

		if (!rm_is_reg(CFI_SP))

			break;



		imm = insn.immediate.value;
@@ -272,7 +278,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 


		if (modrm_reg == CFI_SP) {



			if (modrm_mod == 3) {

			if (mod_is_reg()) {

				/* mov %rsp, reg */

				ADD_OP(op) {

					op->src.type = OP_SRC_REG;
@@ -308,7 +314,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
			break;

		}



		if (modrm_mod == 3 && modrm_rm == CFI_SP) {

		if (rm_is_reg(CFI_SP)) {



			/* mov reg, %rsp */

			ADD_OP(op) {
@@ -325,7 +331,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
		if (!rex_w)

			break;



		if ((modrm_mod == 1 || modrm_mod == 2) && modrm_rm == CFI_BP) {

		if (rm_is_mem(CFI_BP)) {



			/* mov reg, disp(%rbp) */

			ADD_OP(op) {
@@ -338,7 +344,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
			break;

		}



		if (modrm_mod != 3 && rm_is(CFI_SP)) {

		if (rm_is_mem(CFI_SP)) {



			/* mov reg, disp(%rsp) */

			ADD_OP(op) {
@@ -357,7 +363,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
		if (!rex_w)

			break;



		if ((modrm_mod == 1 || modrm_mod == 2) && modrm_rm == CFI_BP) {

		if (rm_is_mem(CFI_BP)) {



			/* mov disp(%rbp), reg */

			ADD_OP(op) {
@@ -370,7 +376,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
			break;

		}



		if (modrm_mod != 3 && rm_is(CFI_SP)) {

		if (rm_is_mem(CFI_SP)) {



			/* mov disp(%rsp), reg */

			ADD_OP(op) {
@@ -386,7 +392,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
		break;



	case 0x8d:

		if (modrm_mod == 3) {

		if (mod_is_reg()) {

			WARN("invalid LEA encoding at %s:0x%lx", sec->name, offset);

			break;

		}