From 468af56a7bbaa626da5a4578bedc930d731fba13 Mon Sep 17 00:00:00 2001 From: Julien Thierry Date: Wed, 14 Oct 2020 08:38:01 +0100 Subject: [PATCH] objtool: Support addition to set CFA base On arm64, the compiler can set the frame pointer either with a move operation or with and add operation like: add (SP + constant), BP For a simple move operation, the CFA base is changed from SP to BP. Handle also changing the CFA base when the frame pointer is set with an addition instruction. Signed-off-by: Julien Thierry Acked-by: Peter Zijlstra (Intel) Signed-off-by: Josh Poimboeuf --- tools/objtool/check.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 88210b0..00d00f9 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1960,6 +1960,17 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi, break; } + if (!cfi->drap && op->src.reg == CFI_SP && + op->dest.reg == CFI_BP && cfa->base == CFI_SP && + check_reg_frame_pos(®s[CFI_BP], -cfa->offset + op->src.offset)) { + + /* lea disp(%rsp), %rbp */ + cfa->base = CFI_BP; + cfa->offset -= op->src.offset; + cfi->bp_scratch = false; + break; + } + if (op->src.reg == CFI_SP && cfa->base == CFI_SP) { /* drap: lea disp(%rsp), %drap */ -- 2.7.4