diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2022-08-18 14:39:27 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-08-19 04:05:42 -0400 |
| commit | e27e5bea956ce4d3eb15112de5fa5a3b77c2f488 (patch) | |
| tree | 3eabfad0e98bac95b5ec1a39d81f9f134ff18a80 | |
| parent | 20ec3ebd707c77fb9b11b37193449193d4649f33 (diff) | |
x86/ibt, objtool: Add IBT_NOSEAL()
Add a macro which prevents a function from getting sealed if there are
no compile-time references to it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Message-Id: <20220818213927.e44fmxkoq4yj6ybn@treble>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/ibt.h | 11 | ||||
| -rw-r--r-- | tools/objtool/check.c | 3 |
2 files changed, 13 insertions, 1 deletions
diff --git a/arch/x86/include/asm/ibt.h b/arch/x86/include/asm/ibt.h index 689880eca9ba..9b08082a5d9f 100644 --- a/arch/x86/include/asm/ibt.h +++ b/arch/x86/include/asm/ibt.h @@ -31,6 +31,16 @@ #define __noendbr __attribute__((nocf_check)) +/* + * Create a dummy function pointer reference to prevent objtool from marking + * the function as needing to be "sealed" (i.e. ENDBR converted to NOP by + * apply_ibt_endbr()). + */ +#define IBT_NOSEAL(fname) \ + ".pushsection .discard.ibt_endbr_noseal\n\t" \ + _ASM_PTR fname "\n\t" \ + ".popsection\n\t" + static inline __attribute_const__ u32 gen_endbr(void) { u32 endbr; @@ -84,6 +94,7 @@ extern __noendbr void ibt_restore(u64 save); #ifndef __ASSEMBLY__ #define ASM_ENDBR +#define IBT_NOSEAL(name) #define __noendbr diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 0cec74da7ffe..91678252a9b6 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4096,7 +4096,8 @@ static int validate_ibt(struct objtool_file *file) * These sections can reference text addresses, but not with * the intent to indirect branch to them. */ - if (!strncmp(sec->name, ".discard", 8) || + if ((!strncmp(sec->name, ".discard", 8) && + strcmp(sec->name, ".discard.ibt_endbr_noseal")) || !strncmp(sec->name, ".debug", 6) || !strcmp(sec->name, ".altinstructions") || !strcmp(sec->name, ".ibt_endbr_seal") || |