[PATCH openEuler-5.10-LTS v2 08/82] um: Cleanup syscall_handler_t definition/cast, fix warning

From: David Gow davidgow@google.com

stable inclusion from stable-v5.10.118 commit ea6a86886caa1ec659dd08b38ca879bacde47123 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L686

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream commit f4f03f299a56ce4d73c5431e0327b3b6cb55ebb9 ]

The syscall_handler_t type for x86_64 was defined as 'long (*)(void)', but always cast to 'long (*)(long, long, long, long, long, long)' before use. This now triggers a warning (see below).

Define syscall_handler_t as the latter instead, and remove the cast. This simplifies the code, and fixes the warning.

Warning: In file included from ../arch/um/include/asm/processor-generic.h:13 from ../arch/x86/um/asm/processor.h:41 from ../include/linux/rcupdate.h:30 from ../include/linux/rculist.h:11 from ../include/linux/pid.h:5 from ../include/linux/sched.h:14 from ../include/linux/ptrace.h:6 from ../arch/um/kernel/skas/syscall.c:7: ../arch/um/kernel/skas/syscall.c: In function ‘handle_syscall’: ../arch/x86/um/shared/sysdep/syscalls_64.h:18:11: warning: cast between incompatible function types from ‘long int (*)(void)’ to ‘long int (*)(long int, long int, long int, long int, long int, long int)’ [ -Wcast-function-type] 18 | (((long (*)(long, long, long, long, long, long)) \ | ^ ../arch/x86/um/asm/ptrace.h:36:62: note: in definition of macro ‘PT_REGS_SET_SYSCALL_RETURN’ 36 | #define PT_REGS_SET_SYSCALL_RETURN(r, res) (PT_REGS_AX(r) = (res)) | ^~~ ../arch/um/kernel/skas/syscall.c:46:33: note: in expansion of macro ‘EXECUTE_SYSCALL’ 46 | EXECUTE_SYSCALL(syscall, regs)); | ^~~~~~~~~~~~~~~

Signed-off-by: David Gow davidgow@google.com Signed-off-by: Richard Weinberger richard@nod.at Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- arch/x86/um/shared/sysdep/syscalls_64.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/um/shared/sysdep/syscalls_64.h b/arch/x86/um/shared/sysdep/syscalls_64.h index 8a7d5e1da98e..1e6875b4ffd8 100644 --- a/arch/x86/um/shared/sysdep/syscalls_64.h +++ b/arch/x86/um/shared/sysdep/syscalls_64.h @@ -10,13 +10,12 @@ #include <linux/msg.h> #include <linux/shm.h>

-typedef long syscall_handler_t(void); +typedef long syscall_handler_t(long, long, long, long, long, long);

extern syscall_handler_t *sys_call_table[];

#define EXECUTE_SYSCALL(syscall, regs) \ - (((long (*)(long, long, long, long, long, long)) \ - (*sys_call_table[syscall]))(UPT_SYSCALL_ARG1(&regs->regs), \ + (((*sys_call_table[syscall]))(UPT_SYSCALL_ARG1(&regs->regs), \ UPT_SYSCALL_ARG2(&regs->regs), \ UPT_SYSCALL_ARG3(&regs->regs), \ UPT_SYSCALL_ARG4(&regs->regs), \