mirror of
https://github.com/lkl/linux.git
synced 2025-12-19 16:13:19 +09:00
0053859496
When a static function is annotated with INDIRECT_CALLABLE_SCOPE and CONFIG_RETPOLINE is set, the static keyword is removed. Sometimes the function needs to be exported but EXPORT_SYMBOL can't be used because if CONFIG_RETPOLINE is not set, we will attempt to export a static symbol. This patch introduces a new indirect call wrapper: EXPORT_INDIRECT_CALLABLE. This basically does EXPORT_SYMBOL when CONFIG_RETPOLINE is set, but does nothing when it's not. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Brian Vazquez <brianvv@google.com> Link: https://lore.kernel.org/r/20210204181839.558951-1-brianvv@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
66 lines
2.1 KiB
C
66 lines
2.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_INDIRECT_CALL_WRAPPER_H
|
|
#define _LINUX_INDIRECT_CALL_WRAPPER_H
|
|
|
|
#ifdef CONFIG_RETPOLINE
|
|
|
|
/*
|
|
* INDIRECT_CALL_$NR - wrapper for indirect calls with $NR known builtin
|
|
* @f: function pointer
|
|
* @f$NR: builtin functions names, up to $NR of them
|
|
* @__VA_ARGS__: arguments for @f
|
|
*
|
|
* Avoid retpoline overhead for known builtin, checking @f vs each of them and
|
|
* eventually invoking directly the builtin function. The functions are check
|
|
* in the given order. Fallback to the indirect call.
|
|
*/
|
|
#define INDIRECT_CALL_1(f, f1, ...) \
|
|
({ \
|
|
likely(f == f1) ? f1(__VA_ARGS__) : f(__VA_ARGS__); \
|
|
})
|
|
#define INDIRECT_CALL_2(f, f2, f1, ...) \
|
|
({ \
|
|
likely(f == f2) ? f2(__VA_ARGS__) : \
|
|
INDIRECT_CALL_1(f, f1, __VA_ARGS__); \
|
|
})
|
|
#define INDIRECT_CALL_3(f, f3, f2, f1, ...) \
|
|
({ \
|
|
likely(f == f3) ? f3(__VA_ARGS__) : \
|
|
INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__); \
|
|
})
|
|
#define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) \
|
|
({ \
|
|
likely(f == f4) ? f4(__VA_ARGS__) : \
|
|
INDIRECT_CALL_3(f, f3, f2, f1, __VA_ARGS__); \
|
|
})
|
|
|
|
#define INDIRECT_CALLABLE_DECLARE(f) f
|
|
#define INDIRECT_CALLABLE_SCOPE
|
|
#define EXPORT_INDIRECT_CALLABLE(f) EXPORT_SYMBOL(f)
|
|
|
|
#else
|
|
#define INDIRECT_CALL_1(f, f1, ...) f(__VA_ARGS__)
|
|
#define INDIRECT_CALL_2(f, f2, f1, ...) f(__VA_ARGS__)
|
|
#define INDIRECT_CALL_3(f, f3, f2, f1, ...) f(__VA_ARGS__)
|
|
#define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) f(__VA_ARGS__)
|
|
#define INDIRECT_CALLABLE_DECLARE(f)
|
|
#define INDIRECT_CALLABLE_SCOPE static
|
|
#define EXPORT_INDIRECT_CALLABLE(f)
|
|
#endif
|
|
|
|
/*
|
|
* We can use INDIRECT_CALL_$NR for ipv6 related functions only if ipv6 is
|
|
* builtin, this macro simplify dealing with indirect calls with only ipv4/ipv6
|
|
* alternatives
|
|
*/
|
|
#if IS_BUILTIN(CONFIG_IPV6)
|
|
#define INDIRECT_CALL_INET(f, f2, f1, ...) \
|
|
INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__)
|
|
#elif IS_ENABLED(CONFIG_INET)
|
|
#define INDIRECT_CALL_INET(f, f2, f1, ...) INDIRECT_CALL_1(f, f1, __VA_ARGS__)
|
|
#else
|
|
#define INDIRECT_CALL_INET(f, f2, f1, ...) f(__VA_ARGS__)
|
|
#endif
|
|
|
|
#endif
|