um: Cleanup syscall_handler_t definition/cast, fix warning

[ 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>
This commit is contained in:
David Gow 2022-02-10 11:43:53 +08:00 committed by Greg Kroah-Hartman
parent c39b91fcd5
commit ea6a86886c

View File

@ -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), \