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For all CONFIG_CFI+CONFIG_CALL_PADDING configs, for C functions, the __cfi_ symbols only cover the 5-byte kCFI type hash. After that there also N bytes of NOP padding between the hash and the function entry which aren't associated with any symbol. The NOPs can be replaced with actual code at runtime. Without a symbol, unwinders and tooling have no way of knowing where those bytes belong. Grow the existing __cfi_* symbols to fill that gap. Note that assembly functions with SYM_TYPED_FUNC_START() aren't affected by this issue, their __cfi_ symbols also cover the padding. Also, CONFIG_PREFIX_SYMBOLS has no reason to exist: CONFIG_CALL_PADDING is what causes the compiler to emit NOP padding before function entry (via -fpatchable-function-entry), so it's the right condition for creating prefix symbols. Remove CONFIG_PREFIX_SYMBOLS, as it's no longer needed. Simplify the LONGEST_SYM_KUNIT_TEST dependency accordingly. Rework objtool's arguments a bit to handle the variety of prefix/cfi-related cases. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> |
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| .. | ||
| arch.h | ||
| builtin.h | ||
| cfi.h | ||
| check.h | ||
| checksum_types.h | ||
| checksum.h | ||
| disas.h | ||
| elf.h | ||
| endianness.h | ||
| klp.h | ||
| objtool.h | ||
| orc.h | ||
| special.h | ||
| trace.h | ||
| util.h | ||
| warn.h | ||