[PATCH] riscv: Mark __se_sys_* functions __used

Sami Tolvanen
2024-03-26T15:37:16Z

Clang doesn't think ___se_sys_* functions used even though they are
aliased to __se_sys_*, resulting in -Wunused-function warnings when
building rv32. For example:

mm/oom_kill.c:1195:1: warning: unused function '___se_sys_process_mrelease' [-Wunused-function]
1195 | SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/syscalls.h:221:36: note: expanded from macro 'SYSCALL_DEFINE2'
221 | #define SYSCALL_DEFINE2(name, ...) SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/syscalls.h:231:2: note: expanded from macro 'SYSCALL_DEFINEx'
231 | __SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/syscall_wrapper.h:81:2: note: expanded from macro '__SYSCALL_DEFINEx'
81 | __SYSCALL_SE_DEFINEx(x, sys, name, __VA_ARGS__) \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/syscall_wrapper.h:40:14: note: expanded from macro '__SYSCALL_SE_DEFINEx'
40 | static long ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))
| ^~~~~~~~~~~~~~~~~~~~
<scratch space>:30:1: note: expanded from here
30 | ___se_sys_process_mrelease
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.

Mark the functions __used explicitly to fix the Clang warnings.

Fixes: a9ad73295cc1 ("riscv: Fix syscall wrapper for >word-size arguments")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
arch/riscv/include/asm/syscall_wrapper.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/include/asm/syscall_wrapper.h b/arch/riscv/include/asm/syscall_wrapper.h
index 980094c2e976..ac80216549ff 100644
--- a/arch/riscv/include/asm/syscall_wrapper.h
+++ b/arch/riscv/include/asm/syscall_wrapper.h
@@ -36,7 +36,8 @@ asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *);
ulong) \
__attribute__((alias(__stringify(___se_##prefix##name)))); \
__diag_pop(); \
- static long noinline ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ static long noinline ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ __used; \
static long ___se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))

#define SC_RISCV_REGS_TO_ARGS(x, ...) \

base-commit: 4cece764965020c22cff7665b18a012006359095
--
2.44.0.396.g6e790dbe36-goog