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| author | Peter Zijlstra <peterz@infradead.org> | 2020-04-01 16:38:19 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-04-22 10:53:50 +0200 |
| commit | e25eea89bb8853763a22fa2547199cf96b571ba1 (patch) | |
| tree | f766e439a5bb171c5c71a56943a684f0e6716723 /tools/arch | |
| parent | b746046238bb99b8f703c79f6d95357428fb6476 (diff) | |
| download | linux-e25eea89bb8853763a22fa2547199cf96b571ba1.tar.gz linux-e25eea89bb8853763a22fa2547199cf96b571ba1.tar.bz2 linux-e25eea89bb8853763a22fa2547199cf96b571ba1.zip | |
objtool: Introduce HINT_RET_OFFSET
Normally objtool ensures a function keeps the stack layout invariant.
But there is a useful exception, it is possible to stuff the return
stack in order to 'inject' a 'call':
push $fun
ret
In this case the invariant mentioned above is violated.
Add an objtool HINT to annotate this and allow a function exit with a
modified stack frame.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20200416115118.690601403@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'tools/arch')
| -rw-r--r-- | tools/arch/x86/include/asm/orc_types.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/arch/x86/include/asm/orc_types.h b/tools/arch/x86/include/asm/orc_types.h index 6e060907c163..5f18ca7ac51a 100644 --- a/tools/arch/x86/include/asm/orc_types.h +++ b/tools/arch/x86/include/asm/orc_types.h @@ -60,6 +60,7 @@ #define ORC_TYPE_REGS_IRET 2 #define UNWIND_HINT_TYPE_SAVE 3 #define UNWIND_HINT_TYPE_RESTORE 4 +#define UNWIND_HINT_TYPE_RET_OFFSET 5 #ifndef __ASSEMBLY__ /* |