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| author | Peter Zijlstra <peterz@infradead.org> | 2021-02-11 13:03:28 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2021-03-06 12:44:22 +0100 |
| commit | d54dba41999498b38a40940e1123019d50b26496 (patch) | |
| tree | c1025dcdb0eb8c6b353913514db3149486b1e535 /tools/objtool/arch | |
| parent | Linux 5.12-rc2 (diff) | |
| download | linux-d54dba41999498b38a40940e1123019d50b26496.tar.xz linux-d54dba41999498b38a40940e1123019d50b26496.zip | |
objtool: Allow UNWIND_HINT to suppress dodgy stack modifications
rewind_stack_do_exit()
UNWIND_HINT_FUNC
/* Prevent any naive code from trying to unwind to our caller. */
xorl %ebp, %ebp
movq PER_CPU_VAR(cpu_current_top_of_stack), %rax
leaq -PTREGS_SIZE(%rax), %rsp
UNWIND_HINT_REGS
call do_exit
Does unspeakable things to the stack, which objtool currently fails to
detect due to a limitation in instruction decoding. This will be
rectified after which the above will result in:
arch/x86/entry/entry_64.o: warning: objtool: .text+0xab: unsupported stack register modification
Allow the UNWIND_HINT on the next instruction to suppress this, it
will overwrite the state anyway.
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lkml.kernel.org/r/20210211173626.918498579@infradead.org
Diffstat (limited to 'tools/objtool/arch')
0 files changed, 0 insertions, 0 deletions