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-rw-r--r--tools/objtool/check.c43
1 files changed, 29 insertions, 14 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f744617c9946..a0c518ecf085 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1203,24 +1203,39 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state)
switch (op->src.type) {
case OP_SRC_REG:
- if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP) {
+ if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP &&
+ cfa->base == CFI_SP &&
+ regs[CFI_BP].base == CFI_CFA &&
+ regs[CFI_BP].offset == -cfa->offset) {
+
+ /* mov %rsp, %rbp */
+ cfa->base = op->dest.reg;
+ state->bp_scratch = false;
+ }
- if (cfa->base == CFI_SP &&
- regs[CFI_BP].base == CFI_CFA &&
- regs[CFI_BP].offset == -cfa->offset) {
+ else if (op->src.reg == CFI_SP &&
+ op->dest.reg == CFI_BP && state->drap) {
- /* mov %rsp, %rbp */
- cfa->base = op->dest.reg;
- state->bp_scratch = false;
- }
+ /* drap: mov %rsp, %rbp */
+ regs[CFI_BP].base = CFI_BP;
+ regs[CFI_BP].offset = -state->stack_size;
+ state->bp_scratch = false;
+ }
- else if (state->drap) {
+ else if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
- /* drap: mov %rsp, %rbp */
- regs[CFI_BP].base = CFI_BP;
- regs[CFI_BP].offset = -state->stack_size;
- state->bp_scratch = false;
- }
+ /*
+ * mov %rsp, %reg
+ *
+ * This is needed for the rare case where GCC
+ * does:
+ *
+ * mov %rsp, %rax
+ * ...
+ * mov %rax, %rsp
+ */
+ state->vals[op->dest.reg].base = CFI_CFA;
+ state->vals[op->dest.reg].offset = -state->stack_size;
}
else if (op->dest.reg == cfa->base) {