Messages in this thread Patch in this message | | | From | Julien Thierry <> | Subject | [PATCH v2 3/3] objtool: check: Make SP memory operation match PUSH/POP semantics | Date | Mon, 28 Sep 2020 10:36:31 +0100 |
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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 <jthierry@redhat.com> --- tools/objtool/check.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 9f7a14a24a65..724293fd1f59 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -2008,6 +2008,14 @@ 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) { @@ -2029,6 +2037,12 @@ 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; @@ -2106,6 +2120,12 @@ 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; -- 2.25.4
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