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[PATCH] LoongArch: Make compute_return_era() return void

Tiezhu Yang posted 1 patch 3 years, 10 months ago 
arch/loongarch/include/asm/branch.h | 3 +--
arch/loongarch/kernel/traps.c       | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)
[PATCH] LoongArch: Make compute_return_era() return void
Posted by Tiezhu Yang 3 years, 10 months ago 
compute_return_era() always returns 0, make it return void,
and then no need to check its return value for its callers.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 arch/loongarch/include/asm/branch.h | 3 +--
 arch/loongarch/kernel/traps.c       | 3 +--
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/include/asm/branch.h b/arch/loongarch/include/asm/branch.h
index 3f33c89..9a133e4 100644
--- a/arch/loongarch/include/asm/branch.h
+++ b/arch/loongarch/include/asm/branch.h
@@ -12,10 +12,9 @@ static inline unsigned long exception_era(struct pt_regs *regs)
 	return regs->csr_era;
 }
 
-static inline int compute_return_era(struct pt_regs *regs)
+static inline void compute_return_era(struct pt_regs *regs)
 {
 	regs->csr_era += 4;
-	return 0;
 }
 
 #endif /* _ASM_BRANCH_H */
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
index e4060f8..1bf58c6 100644
--- a/arch/loongarch/kernel/traps.c
+++ b/arch/loongarch/kernel/traps.c
@@ -475,8 +475,7 @@ asmlinkage void noinstr do_ri(struct pt_regs *regs)
 
 	die_if_kernel("Reserved instruction in kernel code", regs);
 
-	if (unlikely(compute_return_era(regs) < 0))
-		goto out;
+	compute_return_era(regs);
 
 	if (unlikely(get_user(opcode, era) < 0)) {
 		status = SIGSEGV;
-- 
2.1.0
Re: [PATCH] LoongArch: Make compute_return_era() return void
Posted by Huacai Chen 3 years, 10 months ago 
Hi, Tiezhu,

On Sat, Jun 18, 2022 at 4:39 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
> compute_return_era() always returns 0, make it return void,
> and then no need to check its return value for its callers.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  arch/loongarch/include/asm/branch.h | 3 +--
>  arch/loongarch/kernel/traps.c       | 3 +--
>  2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/branch.h b/arch/loongarch/include/asm/branch.h
> index 3f33c89..9a133e4 100644
> --- a/arch/loongarch/include/asm/branch.h
> +++ b/arch/loongarch/include/asm/branch.h
> @@ -12,10 +12,9 @@ static inline unsigned long exception_era(struct pt_regs *regs)
>         return regs->csr_era;
>  }
>
> -static inline int compute_return_era(struct pt_regs *regs)
> +static inline void compute_return_era(struct pt_regs *regs)
>  {
>         regs->csr_era += 4;
> -       return 0;
>  }
>
>  #endif /* _ASM_BRANCH_H */
> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> index e4060f8..1bf58c6 100644
> --- a/arch/loongarch/kernel/traps.c
> +++ b/arch/loongarch/kernel/traps.c
> @@ -475,8 +475,7 @@ asmlinkage void noinstr do_ri(struct pt_regs *regs)
>
>         die_if_kernel("Reserved instruction in kernel code", regs);
>
> -       if (unlikely(compute_return_era(regs) < 0))
> -               goto out;
> +       compute_return_era(regs);
Maybe it is better to simply remove the compute_return_era() function?

Huacai
>
>         if (unlikely(get_user(opcode, era) < 0)) {
>                 status = SIGSEGV;
> --
> 2.1.0
>
Re: [PATCH] LoongArch: Make compute_return_era() return void
Posted by Tiezhu Yang 3 years, 10 months ago 

On 06/23/2022 05:26 PM, Huacai Chen wrote:
> Hi, Tiezhu,
>
> On Sat, Jun 18, 2022 at 4:39 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>>
>> compute_return_era() always returns 0, make it return void,
>> and then no need to check its return value for its callers.
>>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>> ---
>>  arch/loongarch/include/asm/branch.h | 3 +--
>>  arch/loongarch/kernel/traps.c       | 3 +--
>>  2 files changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/loongarch/include/asm/branch.h b/arch/loongarch/include/asm/branch.h
>> index 3f33c89..9a133e4 100644
>> --- a/arch/loongarch/include/asm/branch.h
>> +++ b/arch/loongarch/include/asm/branch.h
>> @@ -12,10 +12,9 @@ static inline unsigned long exception_era(struct pt_regs *regs)
>>         return regs->csr_era;
>>  }
>>
>> -static inline int compute_return_era(struct pt_regs *regs)
>> +static inline void compute_return_era(struct pt_regs *regs)
>>  {
>>         regs->csr_era += 4;
>> -       return 0;
>>  }
>>
>>  #endif /* _ASM_BRANCH_H */
>> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
>> index e4060f8..1bf58c6 100644
>> --- a/arch/loongarch/kernel/traps.c
>> +++ b/arch/loongarch/kernel/traps.c
>> @@ -475,8 +475,7 @@ asmlinkage void noinstr do_ri(struct pt_regs *regs)
>>
>>         die_if_kernel("Reserved instruction in kernel code", regs);
>>
>> -       if (unlikely(compute_return_era(regs) < 0))
>> -               goto out;
>> +       compute_return_era(regs);
> Maybe it is better to simply remove the compute_return_era() function?

Good idea, if so, I think we can also remove exception_era(), and then
arch/loongarch/include/asm/branch.h can be removed.

If you are OK, I will send a v2 patch to remove
arch/loongarch/include/asm/branch.h

Thanks,
Tiezhu

>
> Huacai
>>
>>         if (unlikely(get_user(opcode, era) < 0)) {
>>                 status = SIGSEGV;
>> --
>> 2.1.0
>>
Re: [PATCH] LoongArch: Make compute_return_era() return void
Posted by Huacai Chen 3 years, 10 months ago 
Hi, Tiezhu,

On Thu, Jun 23, 2022 at 5:36 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
>
>
> On 06/23/2022 05:26 PM, Huacai Chen wrote:
> > Hi, Tiezhu,
> >
> > On Sat, Jun 18, 2022 at 4:39 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> >>
> >> compute_return_era() always returns 0, make it return void,
> >> and then no need to check its return value for its callers.
> >>
> >> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> >> ---
> >>  arch/loongarch/include/asm/branch.h | 3 +--
> >>  arch/loongarch/kernel/traps.c       | 3 +--
> >>  2 files changed, 2 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/arch/loongarch/include/asm/branch.h b/arch/loongarch/include/asm/branch.h
> >> index 3f33c89..9a133e4 100644
> >> --- a/arch/loongarch/include/asm/branch.h
> >> +++ b/arch/loongarch/include/asm/branch.h
> >> @@ -12,10 +12,9 @@ static inline unsigned long exception_era(struct pt_regs *regs)
> >>         return regs->csr_era;
> >>  }
> >>
> >> -static inline int compute_return_era(struct pt_regs *regs)
> >> +static inline void compute_return_era(struct pt_regs *regs)
> >>  {
> >>         regs->csr_era += 4;
> >> -       return 0;
> >>  }
> >>
> >>  #endif /* _ASM_BRANCH_H */
> >> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> >> index e4060f8..1bf58c6 100644
> >> --- a/arch/loongarch/kernel/traps.c
> >> +++ b/arch/loongarch/kernel/traps.c
> >> @@ -475,8 +475,7 @@ asmlinkage void noinstr do_ri(struct pt_regs *regs)
> >>
> >>         die_if_kernel("Reserved instruction in kernel code", regs);
> >>
> >> -       if (unlikely(compute_return_era(regs) < 0))
> >> -               goto out;
> >> +       compute_return_era(regs);
> > Maybe it is better to simply remove the compute_return_era() function?
>
> Good idea, if so, I think we can also remove exception_era(), and then
> arch/loongarch/include/asm/branch.h can be removed.
>
> If you are OK, I will send a v2 patch to remove
> arch/loongarch/include/asm/branch.h
After some consideration, I think just taking this version is OK,
because maybe there will be more callers in future. Thanks.

Huacai
>
> Thanks,
> Tiezhu
>
> >
> > Huacai
> >>
> >>         if (unlikely(get_user(opcode, era) < 0)) {
> >>                 status = SIGSEGV;
> >> --
> >> 2.1.0
> >>
>

Patchew 2.1-devel-ea86937

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