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authorJulien Thierry <jthierry@redhat.com>2020-10-14 09:38:02 +0200
committerJosh Poimboeuf <jpoimboe@redhat.com>2021-01-14 01:13:10 +0100
commit201ef5a974e24112953b74cc9f33dcfc4cbcc1cb (patch)
tree5550866c1f4b6fdc2e026c9aed3cd3c89958054e /tools
parentobjtool: Support addition to set CFA base (diff)
downloadlinux-201ef5a974e24112953b74cc9f33dcfc4cbcc1cb.tar.xz
linux-201ef5a974e24112953b74cc9f33dcfc4cbcc1cb.zip
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 <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/objtool/check.c20
1 files changed, 20 insertions, 0 deletions
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;