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MIPS/ptrace: Update mips_get_syscall_arg's return type 

clang warns:

arch/mips/include/asm/syscall.h:136:3: error: variable 'ret' is
uninitialized when used here [-Werror,-Wuninitialized]
                ret |= mips_get_syscall_arg(args++, task, regs, i++);
                ^~~
arch/mips/include/asm/syscall.h:129:9: note: initialize the variable
'ret' to silence this warning
        int ret;
               ^
                = 0
1 error generated.

It's not wrong; however, it's not an issue in practice because ret is
only assigned to, not read from. ret could just be initialized to zero
but looking into it further, ret has been unused since it was first
added in 2012 so just get rid of it and update mips_get_syscall_arg's
return type since none of the return values are ever checked. If it is
ever needed again, this commit can be reverted and ret can be properly
initialized.

Fixes: c0ff3c53d4 ("MIPS: Enable HAVE_ARCH_TRACEHOOK.")
Link: https://github.com/ClangBuiltLinux/linux/issues/604
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
This commit is contained in:
Nathan Chancellor 2019-08-11 20:31:17 -07:00 committed by Paul Burton
parent c2869aafe7
commit 077ff3be06
No known key found for this signature in database
GPG Key ID: 3EA79FACB57500DD
1 changed files with 7 additions and 14 deletions
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21
arch/mips/include/asm/syscall.h
View File

@ -54,7 +54,7 @@ static inline void mips_syscall_update_nr(struct task_struct *task,
task_thread_info(task)->syscall = regs->regs[2];
}
static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
static inline void mips_get_syscall_arg(unsigned long *arg,
struct task_struct *task, struct pt_regs *regs, unsigned int n)
{
unsigned long usp __maybe_unused = regs->regs[29];
@ -63,23 +63,24 @@ static inline unsigned long mips_get_syscall_arg(unsigned long *arg,
case 0: case 1: case 2: case 3:
*arg = regs->regs[4 + n];
return 0;
return;
#ifdef CONFIG_32BIT
case 4: case 5: case 6: case 7:
return get_user(*arg, (int *)usp + n);
get_user(*arg, (int *)usp + n);
return;
#endif
#ifdef CONFIG_64BIT
case 4: case 5: case 6: case 7:
#ifdef CONFIG_MIPS32_O32
if (test_tsk_thread_flag(task, TIF_32BIT_REGS))
return get_user(*arg, (int *)usp + n);
get_user(*arg, (int *)usp + n);
else
#endif
*arg = regs->regs[4 + n];
return 0;
return;
#endif
default:
@ -126,21 +127,13 @@ static inline void syscall_get_arguments(struct task_struct *task,
{
unsigned int i = 0;
unsigned int n = 6;
int ret;
/* O32 ABI syscall() */
if (mips_syscall_is_indirect(task, regs))
i++;
while (n--)
ret |= mips_get_syscall_arg(args++, task, regs, i++);
/*
* No way to communicate an error because this is a void function.
*/
#if 0
return ret;
#endif
mips_get_syscall_arg(args++, task, regs, i++);
}
extern const unsigned long sys_call_table[];