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| author | Peter Zijlstra <peterz@infradead.org> | 2022-10-28 16:50:42 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-11-01 15:44:09 +0300 |
| commit | 9f2899fe36a623885d8576604cb582328ad32b3c (patch) | |
| tree | 2287e0ce43e4c90c254c565f5c63849d365cd614 /tools/objtool/builtin-check.c | |
| parent | 13f60e80e15dd0657c90bcca372ba045630ed9de (diff) | |
| download | linux-9f2899fe36a623885d8576604cb582328ad32b3c.tar.xz | |
objtool: Add option to generate prefix symbols
When code is compiled with:
-fpatchable-function-entry=${PADDING_BYTES},${PADDING_BYTES}
functions will have PADDING_BYTES of NOP in front of them. Unwinders
and other things that symbolize code locations will typically
attribute these bytes to the preceding function.
Given that these bytes nominally belong to the following symbol this
mis-attribution is confusing.
Inspired by the fact that CFI_CLANG emits __cfi_##name symbols to
claim these bytes, allow objtool to emit __pfx_##name symbols to do
the same.
Therefore add the objtool --prefix=N argument, to conditionally place
a __pfx_##name symbol at N bytes ahead of symbol 'name' when: all
these preceding bytes are NOP and name-N is an instruction boundary.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Yujie Liu <yujie.liu@intel.com>
Link: https://lkml.kernel.org/r/20221028194453.526899822@infradead.org
Diffstat (limited to 'tools/objtool/builtin-check.c')
| -rw-r--r-- | tools/objtool/builtin-check.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 0a04f8ea4432..95fcecee60ce 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -75,6 +75,7 @@ const struct option check_options[] = { OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"), OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"), OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"), + OPT_INTEGER(0, "prefix", &opts.prefix, "generate prefix symbols"), OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"), OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"), OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"), |