* [PATCHv2] powerpc: mm: radix_tlb: rearrange the if-else block
@ 2022-01-28 10:08 Anders Roxell
2022-01-28 10:14 ` Christophe Leroy
0 siblings, 1 reply; 3+ messages in thread
From: Anders Roxell @ 2022-01-28 10:08 UTC (permalink / raw)
To: nathan, ndesaulniers, mpe
Cc: linuxppc-dev, linux-kernel, llvm, christophe.leroy,
Anders Roxell, Arnd Bergmann
Clang warns:
arch/powerpc/mm/book3s64/radix_tlb.c:1191:23: error: variable 'hstart' is uninitialized when used here [-Werror,-Wuninitialized]
__tlbiel_va_range(hstart, hend, pid,
^~~~~~
arch/powerpc/mm/book3s64/radix_tlb.c:1175:23: note: initialize the variable 'hstart' to silence this warning
unsigned long hstart, hend;
^
= 0
arch/powerpc/mm/book3s64/radix_tlb.c:1191:31: error: variable 'hend' is uninitialized when used here [-Werror,-Wuninitialized]
__tlbiel_va_range(hstart, hend, pid,
^~~~
arch/powerpc/mm/book3s64/radix_tlb.c:1175:29: note: initialize the variable 'hend' to silence this warning
unsigned long hstart, hend;
^
= 0
2 errors generated.
Rework the 'if (IS_ENABLE(CONFIG_TRANSPARENT_HUGEPAGE))' so hstart/hend
always gets initialized, this will silence the warnings. That will also
simplify the 'else' path. Clang is getting confused with these warnings,
but the warnings is a false-positive.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
---
arch/powerpc/mm/book3s64/radix_tlb.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c
index 7724af19ed7e..7d65965a0688 100644
--- a/arch/powerpc/mm/book3s64/radix_tlb.c
+++ b/arch/powerpc/mm/book3s64/radix_tlb.c
@@ -1174,12 +1174,9 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm,
bool hflush = false;
unsigned long hstart, hend;
- if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
- hstart = (start + PMD_SIZE - 1) & PMD_MASK;
- hend = end & PMD_MASK;
- if (hstart < hend)
- hflush = true;
- }
+ hstart = (start + PMD_SIZE - 1) & PMD_MASK;
+ hend = end & PMD_MASK;
+ hflush = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hstart < hend;
if (type == FLUSH_TYPE_LOCAL) {
asm volatile("ptesync": : :"memory");
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCHv2] powerpc: mm: radix_tlb: rearrange the if-else block
2022-01-28 10:08 [PATCHv2] powerpc: mm: radix_tlb: rearrange the if-else block Anders Roxell
@ 2022-01-28 10:14 ` Christophe Leroy
2022-01-28 13:07 ` Anders Roxell
0 siblings, 1 reply; 3+ messages in thread
From: Christophe Leroy @ 2022-01-28 10:14 UTC (permalink / raw)
To: Anders Roxell, nathan, ndesaulniers, mpe
Cc: linuxppc-dev, linux-kernel, llvm, Arnd Bergmann
Le 28/01/2022 à 11:08, Anders Roxell a écrit :
> Clang warns:
>
> arch/powerpc/mm/book3s64/radix_tlb.c:1191:23: error: variable 'hstart' is uninitialized when used here [-Werror,-Wuninitialized]
> __tlbiel_va_range(hstart, hend, pid,
> ^~~~~~
> arch/powerpc/mm/book3s64/radix_tlb.c:1175:23: note: initialize the variable 'hstart' to silence this warning
> unsigned long hstart, hend;
> ^
> = 0
> arch/powerpc/mm/book3s64/radix_tlb.c:1191:31: error: variable 'hend' is uninitialized when used here [-Werror,-Wuninitialized]
> __tlbiel_va_range(hstart, hend, pid,
> ^~~~
> arch/powerpc/mm/book3s64/radix_tlb.c:1175:29: note: initialize the variable 'hend' to silence this warning
> unsigned long hstart, hend;
> ^
> = 0
> 2 errors generated.
>
> Rework the 'if (IS_ENABLE(CONFIG_TRANSPARENT_HUGEPAGE))' so hstart/hend
> always gets initialized, this will silence the warnings. That will also
> simplify the 'else' path. Clang is getting confused with these warnings,
> but the warnings is a false-positive.
>
> Suggested-by: Arnd Bergmann <arnd@arndb.de>
> Suggested-by: Nathan Chancellor <nathan@kernel.org>
> Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> ---
> arch/powerpc/mm/book3s64/radix_tlb.c | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c
> index 7724af19ed7e..7d65965a0688 100644
> --- a/arch/powerpc/mm/book3s64/radix_tlb.c
> +++ b/arch/powerpc/mm/book3s64/radix_tlb.c
> @@ -1174,12 +1174,9 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm,
> bool hflush = false;
You should then remove the default initialisation of hflush to false
which has become pointless.
With that fixed,
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> unsigned long hstart, hend;
>
> - if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
> - hstart = (start + PMD_SIZE - 1) & PMD_MASK;
> - hend = end & PMD_MASK;
> - if (hstart < hend)
> - hflush = true;
> - }
> + hstart = (start + PMD_SIZE - 1) & PMD_MASK;
> + hend = end & PMD_MASK;
> + hflush = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hstart < hend;
>
> if (type == FLUSH_TYPE_LOCAL) {
> asm volatile("ptesync": : :"memory");
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCHv2] powerpc: mm: radix_tlb: rearrange the if-else block
2022-01-28 10:14 ` Christophe Leroy
@ 2022-01-28 13:07 ` Anders Roxell
0 siblings, 0 replies; 3+ messages in thread
From: Anders Roxell @ 2022-01-28 13:07 UTC (permalink / raw)
To: Christophe Leroy
Cc: nathan, ndesaulniers, mpe, linuxppc-dev, linux-kernel, llvm,
Arnd Bergmann
On Fri, 28 Jan 2022 at 11:14, Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
>
>
> Le 28/01/2022 à 11:08, Anders Roxell a écrit :
> > Clang warns:
> >
> > arch/powerpc/mm/book3s64/radix_tlb.c:1191:23: error: variable 'hstart' is uninitialized when used here [-Werror,-Wuninitialized]
> > __tlbiel_va_range(hstart, hend, pid,
> > ^~~~~~
> > arch/powerpc/mm/book3s64/radix_tlb.c:1175:23: note: initialize the variable 'hstart' to silence this warning
> > unsigned long hstart, hend;
> > ^
> > = 0
> > arch/powerpc/mm/book3s64/radix_tlb.c:1191:31: error: variable 'hend' is uninitialized when used here [-Werror,-Wuninitialized]
> > __tlbiel_va_range(hstart, hend, pid,
> > ^~~~
> > arch/powerpc/mm/book3s64/radix_tlb.c:1175:29: note: initialize the variable 'hend' to silence this warning
> > unsigned long hstart, hend;
> > ^
> > = 0
> > 2 errors generated.
> >
> > Rework the 'if (IS_ENABLE(CONFIG_TRANSPARENT_HUGEPAGE))' so hstart/hend
> > always gets initialized, this will silence the warnings. That will also
> > simplify the 'else' path. Clang is getting confused with these warnings,
> > but the warnings is a false-positive.
> >
> > Suggested-by: Arnd Bergmann <arnd@arndb.de>
> > Suggested-by: Nathan Chancellor <nathan@kernel.org>
> > Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
> > ---
> > arch/powerpc/mm/book3s64/radix_tlb.c | 9 +++------
> > 1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c
> > index 7724af19ed7e..7d65965a0688 100644
> > --- a/arch/powerpc/mm/book3s64/radix_tlb.c
> > +++ b/arch/powerpc/mm/book3s64/radix_tlb.c
> > @@ -1174,12 +1174,9 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm,
> > bool hflush = false;
>
> You should then remove the default initialisation of hflush to false
> which has become pointless.
>
> With that fixed,
>
> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Thank you for the review.
I will send a v3 shortly with that fixed.
Cheers,
Anders
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-01-28 10:08 [PATCHv2] powerpc: mm: radix_tlb: rearrange the if-else block Anders Roxell
2022-01-28 10:14 ` Christophe Leroy
2022-01-28 13:07 ` Anders Roxell
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