diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-03-24 14:55:54 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-03-25 09:20:26 +0100 |
| commit | 1154bbd326de4453858cf78cf29420888b3ffd52 (patch) | |
| tree | db9cd0e9917f125378a832a2386bee95a33f1896 /tools/objtool/include | |
| parent | c84301d706c5456b1460439b2987a0f0b6362a82 (diff) | |
objtool: Fix X86_FEATURE_SMAP alternative handling
For X86_FEATURE_SMAP alternatives which replace NOP with STAC or CLAC,
uaccess validation skips the NOP branch to avoid following impossible
code paths, e.g. where a STAC would be patched but a CLAC wouldn't.
However, it's not safe to assume an X86_FEATURE_SMAP alternative is
patching STAC/CLAC. There can be other alternatives, like
static_cpu_has(), where both branches need to be validated.
Fix that by repurposing ANNOTATE_IGNORE_ALTERNATIVE for skipping either
original instructions or new ones. This is a more generic approach
which enables the removal of the feature checking hacks and the
insn->ignore bit.
Fixes the following warnings:
arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8ec: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h
arch/x86/mm/fault.o: warning: objtool: do_user_addr_fault+0x8f1: unreachable instruction
[ mingo: Fix up conflicts with recent x86 changes. ]
Fixes: ea24213d8088 ("objtool: Add UACCESS validation")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/de0621ca242130156a55d5d74fed86994dfa4c9c.1742852846.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/oe-kbuild-all/202503181736.zkZUBv4N-lkp@intel.com/
Diffstat (limited to 'tools/objtool/include')
| -rw-r--r-- | tools/objtool/include/objtool/check.h | 3 | ||||
| -rw-r--r-- | tools/objtool/include/objtool/special.h | 4 |
2 files changed, 3 insertions, 4 deletions
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h index e1cd13cd28a3..00fb745e7233 100644 --- a/tools/objtool/include/objtool/check.h +++ b/tools/objtool/include/objtool/check.h @@ -34,6 +34,8 @@ struct alt_group { * This is shared with the other alt_groups in the same alternative. */ struct cfi_state **cfi; + + bool ignore; }; #define INSN_CHUNK_BITS 8 @@ -54,7 +56,6 @@ struct instruction { u32 idx : INSN_CHUNK_BITS, dead_end : 1, - ignore : 1, ignore_alts : 1, hint : 1, save : 1, diff --git a/tools/objtool/include/objtool/special.h b/tools/objtool/include/objtool/special.h index e049679bb17b..72d09c0adf1a 100644 --- a/tools/objtool/include/objtool/special.h +++ b/tools/objtool/include/objtool/special.h @@ -16,8 +16,6 @@ struct special_alt { struct list_head list; bool group; - bool skip_orig; - bool skip_alt; bool jump_or_nop; u8 key_addend; @@ -32,7 +30,7 @@ struct special_alt { int special_get_alts(struct elf *elf, struct list_head *alts); -void arch_handle_alternative(unsigned short feature, struct special_alt *alt); +void arch_handle_alternative(struct special_alt *alt); bool arch_support_alt_relocation(struct special_alt *special_alt, struct instruction *insn, |