linux/arch/riscv/include/asm/syscall_wrapper.h
Sami Tolvanen 653650c468
riscv: Mark __se_sys_* functions __used
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: a9ad73295c ("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>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240326153712.1839482-2-samitolvanen@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2024-03-26 14:11:03 -07:00

109 lines
4.0 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* syscall_wrapper.h - riscv specific wrappers to syscall definitions
*
* Based on arch/arm64/include/syscall_wrapper.h
*/
#ifndef __ASM_SYSCALL_WRAPPER_H
#define __ASM_SYSCALL_WRAPPER_H
#include <asm/ptrace.h>
asmlinkage long __riscv_sys_ni_syscall(const struct pt_regs *);
#ifdef CONFIG_64BIT
#define __SYSCALL_SE_DEFINEx(x, prefix, name, ...) \
static long __se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
static long __se_##prefix##name(__MAP(x,__SC_LONG,__VA_ARGS__))
#define SC_RISCV_REGS_TO_ARGS(x, ...) \
__MAP(x,__SC_ARGS \
,,regs->orig_a0,,regs->a1,,regs->a2 \
,,regs->a3,,regs->a4,,regs->a5,,regs->a6)
#else
/*
* Use type aliasing to ensure registers a0-a6 are correctly passed to the syscall
* implementation when >word-size arguments are used.
*/
#define __SYSCALL_SE_DEFINEx(x, prefix, name, ...) \
__diag_push(); \
__diag_ignore(GCC, 8, "-Wattribute-alias", \
"Type aliasing is used to sanitize syscall arguments"); \
static long __se_##prefix##name(ulong, ulong, ulong, ulong, ulong, ulong, \
ulong) \
__attribute__((alias(__stringify(___se_##prefix##name)))); \
__diag_pop(); \
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, ...) \
regs->orig_a0,regs->a1,regs->a2,regs->a3,regs->a4,regs->a5,regs->a6
#endif /* CONFIG_64BIT */
#ifdef CONFIG_COMPAT
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__riscv_compat_sys##name, ERRNO); \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
__SYSCALL_SE_DEFINEx(x, compat_sys, name, __VA_ARGS__) \
{ \
return __do_compat_sys##name(__MAP(x,__SC_DELOUSE,__VA_ARGS__)); \
} \
asmlinkage long __riscv_compat_sys##name(const struct pt_regs *regs) \
{ \
return __se_compat_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
} \
static inline long __do_compat_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
#define COMPAT_SYSCALL_DEFINE0(sname) \
asmlinkage long __riscv_compat_sys_##sname(const struct pt_regs *__unused); \
ALLOW_ERROR_INJECTION(__riscv_compat_sys_##sname, ERRNO); \
asmlinkage long __riscv_compat_sys_##sname(const struct pt_regs *__unused)
#define COND_SYSCALL_COMPAT(name) \
asmlinkage long __weak __riscv_compat_sys_##name(const struct pt_regs *regs); \
asmlinkage long __weak __riscv_compat_sys_##name(const struct pt_regs *regs) \
{ \
return sys_ni_syscall(); \
}
#endif /* CONFIG_COMPAT */
#define __SYSCALL_DEFINEx(x, name, ...) \
asmlinkage long __riscv_sys##name(const struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__riscv_sys##name, ERRNO); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
__SYSCALL_SE_DEFINEx(x, sys, name, __VA_ARGS__) \
{ \
long ret = __do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__)); \
__MAP(x,__SC_TEST,__VA_ARGS__); \
__PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
return ret; \
} \
asmlinkage long __riscv_sys##name(const struct pt_regs *regs) \
{ \
return __se_sys##name(SC_RISCV_REGS_TO_ARGS(x,__VA_ARGS__)); \
} \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
asmlinkage long __riscv_sys_##sname(const struct pt_regs *__unused); \
ALLOW_ERROR_INJECTION(__riscv_sys_##sname, ERRNO); \
asmlinkage long __riscv_sys_##sname(const struct pt_regs *__unused)
#define COND_SYSCALL(name) \
asmlinkage long __weak __riscv_sys_##name(const struct pt_regs *regs); \
asmlinkage long __weak __riscv_sys_##name(const struct pt_regs *regs) \
{ \
return sys_ni_syscall(); \
}
#endif /* __ASM_SYSCALL_WRAPPER_H */