From 201ef5a974e24112953b74cc9f33dcfc4cbcc1cb Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Wed, 14 Oct 2020 08:38:02 +0100 Subject: objtool: Make SP memory operation match PUSH/POP semantics Architectures without PUSH/POP instructions will always access the stack though memory operations (SRC/DEST_INDIRECT). Make those operations have the same effect on the CFA as PUSH/POP, with no stack pointer modification. Signed-off-by: Julien Thierry Acked-by: Peter Zijlstra (Intel) Signed-off-by: Josh Poimboeuf --- tools/objtool/check.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'tools/objtool') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 00d00f904536..270adc38d896 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2065,6 +2065,14 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi, break; case OP_SRC_REG_INDIRECT: + if (!cfi->drap && op->dest.reg == cfa->base && + op->dest.reg == CFI_BP) { + + /* mov disp(%rsp), %rbp */ + cfa->base = CFI_SP; + cfa->offset = cfi->stack_size; + } + if (cfi->drap && op->src.reg == CFI_BP && op->src.offset == cfi->drap_offset) { @@ -2086,6 +2094,12 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi, /* mov disp(%rbp), %reg */ /* mov disp(%rsp), %reg */ restore_reg(cfi, op->dest.reg); + + } else if (op->src.reg == CFI_SP && + op->src.offset == regs[op->dest.reg].offset + cfi->stack_size) { + + /* mov disp(%rsp), %reg */ + restore_reg(cfi, op->dest.reg); } break; @@ -2163,6 +2177,12 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi, /* mov reg, disp(%rsp) */ save_reg(cfi, op->src.reg, CFI_CFA, op->dest.offset - cfi->cfa.offset); + + } else if (op->dest.reg == CFI_SP) { + + /* mov reg, disp(%rsp) */ + save_reg(cfi, op->src.reg, CFI_CFA, + op->dest.offset - cfi->stack_size); } break; -- cgit v1.2.3