Commit ffc7e74f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

objtool,x86: Rewrite LEAVE 



Since we can now have multiple stack-ops per instruction, we don't
need to special case LEAVE and can simply emit the composite
operations.

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>
Tested-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Link: https://lkml.kernel.org/r/20210211173627.253273977@infradead.org
parent 2ee0c363

tools/objtool/arch/x86/decode.c

+11 −3
Original line number Diff line number Diff line
@@ -446,9 +446,17 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, 
		 * mov bp, sp

		 * pop bp

		 */

		ADD_OP(op)

			op->dest.type = OP_DEST_LEAVE;



		ADD_OP(op) {

			op->src.type = OP_SRC_REG;

			op->src.reg = CFI_BP;

			op->dest.type = OP_DEST_REG;

			op->dest.reg = CFI_SP;

		}

		ADD_OP(op) {

			op->src.type = OP_SRC_POP;

			op->dest.type = OP_DEST_REG;

			op->dest.reg = CFI_BP;

		}

		break;



	case 0xe3:

tools/objtool/check.c

+2 −22
Original line number Diff line number Diff line
@@ -2020,7 +2020,7 @@ static int update_cfi_state(struct instruction *insn, 
			}



			else if (op->src.reg == CFI_BP && op->dest.reg == CFI_SP &&

				 cfa->base == CFI_BP) {

				 (cfa->base == CFI_BP || cfa->base == cfi->drap_reg)) {



				/*

				 * mov %rbp, %rsp
@@ -2217,7 +2217,7 @@ static int update_cfi_state(struct instruction *insn, 
				cfa->offset = 0;

				cfi->drap_offset = -1;



			} else if (regs[op->dest.reg].offset == -cfi->stack_size) {

			} else if (cfi->stack_size == -regs[op->dest.reg].offset) {



				/* pop %reg */

				restore_reg(cfi, op->dest.reg);
@@ -2358,26 +2358,6 @@ static int update_cfi_state(struct instruction *insn, 


		break;



	case OP_DEST_LEAVE:

		if ((!cfi->drap && cfa->base != CFI_BP) ||

		    (cfi->drap && cfa->base != cfi->drap_reg)) {

			WARN_FUNC("leave instruction with modified stack frame",

				  insn->sec, insn->offset);

			return -1;

		}



		/* leave (mov %rbp, %rsp; pop %rbp) */



		cfi->stack_size = -cfi->regs[CFI_BP].offset - 8;

		restore_reg(cfi, CFI_BP);



		if (!cfi->drap) {

			cfa->base = CFI_SP;

			cfa->offset -= 8;

		}



		break;



	case OP_DEST_MEM:

		if (op->src.type != OP_SRC_POP && op->src.type != OP_SRC_POPF) {

			WARN_FUNC("unknown stack-related memory operation",

tools/objtool/include/objtool/arch.h

+0 −1
Original line number Diff line number Diff line
@@ -35,7 +35,6 @@ enum op_dest_type { 
	OP_DEST_MEM,

	OP_DEST_PUSH,

	OP_DEST_PUSHF,

	OP_DEST_LEAVE,

};



struct op_dest {