Messages in this thread Patch in this message | | | Date | Thu, 16 Apr 2020 17:07:54 +0200 | From | Peter Zijlstra <> | Subject | [RFC][PATCH 2/7] objtool: UNWIND_HINT_RET_OFFSET should not check registers |
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From: Alexandre Chartre <alexandre.chartre@oracle.com>
UNWIND_HINT_RET_OFFSET will adjust a modified stack. However if a callee-saved register was pushed on the stack then the stack frame will still appear modified. So stop checking registers when UNWIND_HINT_RET_OFFSET is used.
Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200407073142.20659-3-alexandre.chartre@oracle.com --- tools/objtool/check.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1513,6 +1513,14 @@ static bool has_modified_stack_frame(str if (cfi->stack_size != initial_func_cfi.cfa.offset + ret_offset) return true; + /* + * If there is a ret offset hint then don't check registers + * because a callee-saved register might have been pushed on + * the stack. + */ + if (ret_offset) + return false; + for (i = 0; i < CFI_NUM_REGS; i++) { if (cfi->regs[i].base != initial_func_cfi.regs[i].base || cfi->regs[i].offset != initial_func_cfi.regs[i].offset)
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