Messages in this thread Patch in this message | | | From | Julien Thierry <> | Subject | [PATCH 2/3] objtool: check: Support addition to set CFA base | Date | Tue, 15 Sep 2020 09:12:03 +0100 |
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Instead of "mov SP, BP", a compiler could simply set BP to SP + constant. Handle changing the CFA base in such cases.
Signed-off-by: Julien Thierry <jthierry@redhat.com> --- tools/objtool/check.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 7db6761d28c2..f45991c2db41 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1898,6 +1898,19 @@ 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 + CFA_SIZE, + CFA_BP_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 */ -- 2.21.3
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