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authorPeter Zijlstra <peterz@infradead.org>2021-02-18 17:14:10 +0100
committerThomas Gleixner <tglx@linutronix.de>2021-02-22 19:54:09 +0100
commit724c8a23d589d8a002d2e39633c2f9a5a429616f (patch)
tree623c789a1ed733adbc2d11b50449f08a7d95404b /tools
parent3aac798a917be3b8f2f647b834bb06bf2f8df4f1 (diff)
downloadlinux-724c8a23d589d8a002d2e39633c2f9a5a429616f.tar.bz2
objtool: Fix stack-swizzle for FRAME_POINTER=y
When objtool encounters the stack-swizzle: mov %rsp, (%[tos]) mov %[tos], %rsp ... pop %rsp Inside a FRAME_POINTER=y build, things go a little screwy because clearly we're not adjusting the cfa->base. This then results in the pop %rsp not being detected as a restore of cfa->base so it will turn into a regular POP and offset the stack, resulting in: kernel/softirq.o: warning: objtool: do_softirq()+0xdb: return with modified stack frame Therefore, have "mov %[tos], %rsp" act like a PUSH (it sorta is anyway) to balance the things out. We're not too concerned with the actual stack_size for frame-pointer builds, since we don't generate ORC data for them anyway. Fixes: aafeb14e9da2 ("objtool: Support stack-swizzle") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/YC6UC+rc9KKmQrkd@hirez.programming.kicks-ass.net
Diffstat (limited to 'tools')
-rw-r--r--tools/objtool/check.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 8e74210f4235..2087974c70d3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1983,6 +1983,20 @@ static int update_cfi_state(struct instruction *insn, struct cfi_state *cfi,
}
}
+ else if (op->dest.reg == CFI_SP &&
+ cfi->vals[op->src.reg].base == CFI_SP_INDIRECT &&
+ cfi->vals[op->src.reg].offset == cfa->offset) {
+
+ /*
+ * The same stack swizzle case 2) as above. But
+ * because we can't change cfa->base, case 3)
+ * will become a regular POP. Pretend we're a
+ * PUSH so things don't go unbalanced.
+ */
+ cfi->stack_size += 8;
+ }
+
+
break;
case OP_SRC_ADD: