diff options
| author | Josh Poimboeuf | 2021-01-21 15:29:24 -0600 |
|---|---|---|
| committer | Josh Poimboeuf | 2021-01-26 11:12:00 -0600 |
| commit | b735bd3e68824316655252a931a3353a6ebc036f (patch) | |
| tree | 24a879a66b4ce0549a05d2aca3ec81dab212b128 /tools/include | |
| parent | 081df94301e317e84c3413686043987da2c3e39d (diff) | |
objtool: Combine UNWIND_HINT_RET_OFFSET and UNWIND_HINT_FUNC
The ORC metadata generated for UNWIND_HINT_FUNC isn't actually very
func-like. With certain usages it can cause stack state mismatches
because it doesn't set the return address (CFI_RA).
Also, users of UNWIND_HINT_RET_OFFSET no longer need to set a custom
return stack offset. Instead they just need to specify a func-like
situation, so the current ret_offset code is hacky for no good reason.
Solve both problems by simplifying the RET_OFFSET handling and
converting it into a more useful UNWIND_HINT_FUNC.
If we end up needing the old 'ret_offset' functionality again in the
future, we should be able to support it pretty easily with the addition
of a custom 'sp_offset' in UNWIND_HINT_FUNC.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/db9d1f5d79dddfbb3725ef6d8ec3477ad199948d.1611263462.git.jpoimboe@redhat.com
Diffstat (limited to 'tools/include')
| -rw-r--r-- | tools/include/linux/objtool.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h index add1c6eb157e..7e72d975cb76 100644 --- a/tools/include/linux/objtool.h +++ b/tools/include/linux/objtool.h @@ -29,11 +29,14 @@ struct unwind_hint { * * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that * sp_reg+sp_offset points to the iret return frame. + * + * UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function. + * Useful for code which doesn't have an ELF function annotation. */ #define UNWIND_HINT_TYPE_CALL 0 #define UNWIND_HINT_TYPE_REGS 1 #define UNWIND_HINT_TYPE_REGS_PARTIAL 2 -#define UNWIND_HINT_TYPE_RET_OFFSET 3 +#define UNWIND_HINT_TYPE_FUNC 3 #ifdef CONFIG_STACK_VALIDATION |