objtool: Remove annotate_{,un}reachable()

There are no users of annotate_reachable() left.

And the annotate_unreachable() usage in unreachable() is plain wrong;
it will hide dangerous fall-through code-gen.

Remove both.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20241128094312.235637588@infradead.org
This commit is contained in:
Peter Zijlstra
2024-11-28 10:39:04 +01:00
parent 624bde3465
commit 06e2474598
2 changed files with 2 additions and 68 deletions

View File

@@ -109,35 +109,9 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
/* Unreachable code */
#ifdef CONFIG_OBJTOOL
/*
* These macros help objtool understand GCC code flow for unreachable code.
* The __COUNTER__ based labels are a hack to make each instance of the macros
* unique, to convince GCC not to merge duplicate inline asm statements.
*/
#define __stringify_label(n) #n
#define __annotate_reachable(c) ({ \
asm volatile(__stringify_label(c) ":\n\t" \
".pushsection .discard.reachable\n\t" \
".long " __stringify_label(c) "b - .\n\t" \
".popsection\n\t"); \
})
#define annotate_reachable() __annotate_reachable(__COUNTER__)
#define __annotate_unreachable(c) ({ \
asm volatile(__stringify_label(c) ":\n\t" \
".pushsection .discard.unreachable\n\t" \
".long " __stringify_label(c) "b - .\n\t" \
".popsection\n\t" : : "i" (c)); \
})
#define annotate_unreachable() __annotate_unreachable(__COUNTER__)
/* Annotate a C jump table to allow objtool to follow the code flow */
#define __annotate_jump_table __section(".rodata..c_jump_table,\"a\",@progbits #")
#else /* !CONFIG_OBJTOOL */
#define annotate_reachable()
#define annotate_unreachable()
#define __annotate_jump_table
#endif /* CONFIG_OBJTOOL */
@@ -147,7 +121,6 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
* control elsewhere.
*/
#define unreachable() do { \
annotate_unreachable(); \
barrier_before_unreachable(); \
__builtin_unreachable(); \
} while (0)