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| author | Peter Zijlstra <peterz@infradead.org> | 2022-06-14 23:16:03 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-06-27 10:34:00 +0200 |
| commit | a09a6e2399ba0595c3042b3164f3ca68a3cff33e (patch) | |
| tree | bf16062820b967a0b9c59169adf156eec8ed55a4 /tools/include | |
| parent | 0fe4aeea9c01baabecc8c3afc7889c809d939bc2 (diff) | |
| download | linux-a09a6e2399ba0595c3042b3164f3ca68a3cff33e.tar.gz linux-a09a6e2399ba0595c3042b3164f3ca68a3cff33e.tar.bz2 linux-a09a6e2399ba0595c3042b3164f3ca68a3cff33e.zip | |
objtool: Add entry UNRET validation
Since entry asm is tricky, add a validation pass that ensures the
retbleed mitigation has been done before the first actual RET
instruction.
Entry points are those that either have UNWIND_HINT_ENTRY, which acts
as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or
those that have UWIND_HINT_IRET_REGS at +0.
This is basically a variant of validate_branch() that is
intra-function and it will simply follow all branches from marked
entry points and ensures that all paths lead to ANNOTATE_UNRET_END.
If a path hits RET or an indirection the path is a fail and will be
reported.
There are 3 ANNOTATE_UNRET_END instances:
- UNTRAIN_RET itself
- exception from-kernel; this path doesn't need UNTRAIN_RET
- all early exceptions; these also don't need UNTRAIN_RET
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'tools/include')
| -rw-r--r-- | tools/include/linux/objtool.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h index 15b940ec1eac..b026f1ae39c6 100644 --- a/tools/include/linux/objtool.h +++ b/tools/include/linux/objtool.h @@ -32,11 +32,14 @@ struct unwind_hint { * * UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function. * Useful for code which doesn't have an ELF function annotation. + * + * UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc. */ #define UNWIND_HINT_TYPE_CALL 0 #define UNWIND_HINT_TYPE_REGS 1 #define UNWIND_HINT_TYPE_REGS_PARTIAL 2 #define UNWIND_HINT_TYPE_FUNC 3 +#define UNWIND_HINT_TYPE_ENTRY 4 #ifdef CONFIG_OBJTOOL |