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| author | Peter Zijlstra <peterz@infradead.org> | 2021-02-18 17:14:10 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-02-22 19:54:09 +0100 |
| commit | 724c8a23d589d8a002d2e39633c2f9a5a429616f (patch) | |
| tree | 623c789a1ed733adbc2d11b50449f08a7d95404b | |
| parent | um: Enforce the usage of asm-generic/softirq_stack.h (diff) | |
| download | linux-724c8a23d589d8a002d2e39633c2f9a5a429616f.tar.xz linux-724c8a23d589d8a002d2e39633c2f9a5a429616f.zip | |
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
| -rw-r--r-- | tools/objtool/check.c | 14 |
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: |