[PATCH] powerpc: process.c: fix Kconfig typo

[PATCH] powerpc: process.c: fix Kconfig typo

[Valentin Rothberg]

s/ALIVEC/ALTIVEC/

Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
---
 arch/powerpc/kernel/process.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9e7c10fe205f..ce6dc61b15b2 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1012,7 +1012,7 @@ void restore_tm_state(struct pt_regs *regs)
 	/* Ensure that restore_math() will restore */
 	if (msr_diff & MSR_FP)
 		current->thread.load_fp = 1;
-#ifdef CONFIG_ALIVEC
+#ifdef CONFIG_ALTIVEC
 	if (cpu_has_feature(CPU_FTR_ALTIVEC) && msr_diff & MSR_VEC)
 		current->thread.load_vec = 1;
 #endif
-- 
2.9.3

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Cyril Bur]

On Wed, 2016-10-05 at 07:57 +0200, Valentin Rothberg wrote:
> s/ALIVEC/ALTIVEC/
> 

Oops, nice catch

> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>

Reviewed-by: Cyril Bur <cyrilbur@gmail.com>

> ---
>  arch/powerpc/kernel/process.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/kernel/process.c
> b/arch/powerpc/kernel/process.c
> index 9e7c10fe205f..ce6dc61b15b2 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -1012,7 +1012,7 @@ void restore_tm_state(struct pt_regs *regs)
>  	/* Ensure that restore_math() will restore */
>  	if (msr_diff & MSR_FP)
>  		current->thread.load_fp = 1;
> -#ifdef CONFIG_ALIVEC
> +#ifdef CONFIG_ALTIVEC
>  	if (cpu_has_feature(CPU_FTR_ALTIVEC) && msr_diff & MSR_VEC)
>  		current->thread.load_vec = 1;
>  #endif

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Michael Ellerman]

Cyril Bur <cyrilbur@gmail.com> writes:

> On Wed, 2016-10-05 at 07:57 +0200, Valentin Rothberg wrote:
>> s/ALIVEC/ALTIVEC/
>> 
>
> Oops, nice catch
>
>> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
>
> Reviewed-by: Cyril Bur <cyrilbur@gmail.com>

How did we not notice? Sounds like we need a new selftest.

Looks like this should have:

Fixes: dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware transactional memory in use")


And I guess I need to start running checkkconfigsymbols.py on every
commit.

cheers

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Valentin Rothberg]

On Wed, Oct 26, 2016 at 7:52 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
> Cyril Bur <cyrilbur@gmail.com> writes:
>
>> On Wed, 2016-10-05 at 07:57 +0200, Valentin Rothberg wrote:
>>> s/ALIVEC/ALTIVEC/
>>>
>>
>> Oops, nice catch
>>
>>> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
>>
>> Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
>
> How did we not notice? Sounds like we need a new selftest.
>
> Looks like this should have:
>
> Fixes: dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware transactional memory in use")
>
>
> And I guess I need to start running checkkconfigsymbols.py on every
> commit.

Happy to find a new user :-)  You can also run the script on a range
of commits via '--diff commitA..commitB', which can safe some time.

Best regards,
 Valentin

> cheers

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Michael Ellerman]

Valentin Rothberg <valentinrothberg@gmail.com> writes:

> On Wed, Oct 26, 2016 at 7:52 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
>> Cyril Bur <cyrilbur@gmail.com> writes:
>>
>>> On Wed, 2016-10-05 at 07:57 +0200, Valentin Rothberg wrote:
>>>> s/ALIVEC/ALTIVEC/
>>>>
>>>
>>> Oops, nice catch
>>>
>>>> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
>>>
>>> Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
>>
>> How did we not notice? Sounds like we need a new selftest.
>>
>> Looks like this should have:
>>
>> Fixes: dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware transactional memory in use")
>>
>>
>> And I guess I need to start running checkkconfigsymbols.py on every
>> commit.
>
> Happy to find a new user :-)  You can also run the script on a range
> of commits via '--diff commitA..commitB', which can safe some time.

Yeah I just discovered that, very useful.

But my instinct was to do:

$ ./scripts/checkkconfigsymbols.py --diff HEAD^^^..HEAD

Which didn't work, the regexp is a bit tight, fixed by:

diff --git a/scripts/checkkconfigsymbols.py b/scripts/checkkconfigsymbols.py
index a32e4da4c117..3820f00b066a 100755
--- a/scripts/checkkconfigsymbols.py
+++ b/scripts/checkkconfigsymbols.py
@@ -88,7 +88,7 @@ def parse_options():
     if args.commit and args.diff:
         sys.exit("Please specify only one option at once.")
 
-    if args.diff and not re.match(r"^[\w\-\.]+\.\.[\w\-\.]+$", args.diff):
+    if args.diff and not re.match(r"^[\w\-\.\^]+\.\.[\w\-\.\^]+$", args.diff):
         sys.exit("Please specify valid input in the following format: "
                  "\'commit1..commit2\'")
 


cheers

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Valentin Rothberg]

On Wed, Oct 26, 2016 at 12:40 PM, Michael Ellerman <mpe@ellerman.id.au> wrote:
> Valentin Rothberg <valentinrothberg@gmail.com> writes:
>
>> On Wed, Oct 26, 2016 at 7:52 AM, Michael Ellerman <mpe@ellerman.id.au> wrote:
>>> Cyril Bur <cyrilbur@gmail.com> writes:
>>>
>>>> On Wed, 2016-10-05 at 07:57 +0200, Valentin Rothberg wrote:
>>>>> s/ALIVEC/ALTIVEC/
>>>>>
>>>>
>>>> Oops, nice catch
>>>>
>>>>> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
>>>>
>>>> Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
>>>
>>> How did we not notice? Sounds like we need a new selftest.
>>>
>>> Looks like this should have:
>>>
>>> Fixes: dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware transactional memory in use")
>>>
>>>
>>> And I guess I need to start running checkkconfigsymbols.py on every
>>> commit.
>>
>> Happy to find a new user :-)  You can also run the script on a range
>> of commits via '--diff commitA..commitB', which can safe some time.
>
> Yeah I just discovered that, very useful.
>
> But my instinct was to do:
>
> $ ./scripts/checkkconfigsymbols.py --diff HEAD^^^..HEAD
>
> Which didn't work, the regexp is a bit tight, fixed by:
>
> diff --git a/scripts/checkkconfigsymbols.py b/scripts/checkkconfigsymbols.py
> index a32e4da4c117..3820f00b066a 100755
> --- a/scripts/checkkconfigsymbols.py
> +++ b/scripts/checkkconfigsymbols.py
> @@ -88,7 +88,7 @@ def parse_options():
>      if args.commit and args.diff:
>          sys.exit("Please specify only one option at once.")
>
> -    if args.diff and not re.match(r"^[\w\-\.]+\.\.[\w\-\.]+$", args.diff):
> +    if args.diff and not re.match(r"^[\w\-\.\^]+\.\.[\w\-\.\^]+$", args.diff):
>          sys.exit("Please specify valid input in the following format: "
>                   "\'commit1..commit2\'")

Looks great.  If you agree, I'll pick this up and send the patch to
Greg (who takes patches for this script)?

Thanks,
 Valentin

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Michael Ellerman]

Valentin Rothberg <valentinrothberg@gmail.com> writes:
> On Wed, Oct 26, 2016 at 12:40 PM, Michael Ellerman <mpe@ellerman.id.au> wrote:
>> diff --git a/scripts/checkkconfigsymbols.py b/scripts/checkkconfigsymbols.py
>> index a32e4da4c117..3820f00b066a 100755
>> --- a/scripts/checkkconfigsymbols.py
>> +++ b/scripts/checkkconfigsymbols.py
>> @@ -88,7 +88,7 @@ def parse_options():
>>      if args.commit and args.diff:
>>          sys.exit("Please specify only one option at once.")
>>
>> -    if args.diff and not re.match(r"^[\w\-\.]+\.\.[\w\-\.]+$", args.diff):
>> +    if args.diff and not re.match(r"^[\w\-\.\^]+\.\.[\w\-\.\^]+$", args.diff):
>>          sys.exit("Please specify valid input in the following format: "
>>                   "\'commit1..commit2\'")
>
> Looks great.  If you agree, I'll pick this up and send the patch to
> Greg (who takes patches for this script)?

That'd be great, thanks.

cheers

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Cyril Bur]

On Wed, 2016-10-26 at 16:52 +1100, Michael Ellerman wrote:
> Cyril Bur <cyrilbur@gmail.com> writes:
> 
> > On Wed, 2016-10-05 at 07:57 +0200, Valentin Rothberg wrote:
> > > s/ALIVEC/ALTIVEC/
> > > 
> > 
> > Oops, nice catch
> > 
> > > Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>
> > 
> > Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
> 
> How did we not notice? Sounds like we need a new selftest.
> 

Indeed...

Here is probably a good place to say why we didn't catch it and under
what circumstances this will have a negative effect.

If a thread performs and transaction with altivec and then gets
preempted for whatever reason, this bug may cause the kernel to not
reenable altivec when that thread runs again. This will result in an
altivec unavailable fault, when these faults happen inside a user
transaction the kernel has no choice but enable altivec and doom the
transaction.

The result is that transactions using altivec may get aborted more than
they should.

The difficulty in catching this with a selftest is my deliberate use of
the word may above. Optimisations to avoid FPU/altivec/VSX faults mean
that the kernel will always leave them on for 255 switches, this code
prevents the kernel turning it off if it got to the 256th switch (and
userspace was transactional)...


Cyril

> Looks like this should have:
> 
> Fixes: dc16b553c949 ("powerpc: Always restore FPU/VEC/VSX if hardware
> transactional memory in use")
> 
> 
> And I guess I need to start running checkkconfigsymbols.py on every
> commit.
> 
> cheers

Re: [PATCH] powerpc: process.c: fix Kconfig typo

[Michael Ellerman]

Valentin Rothberg <valentinrothberg@gmail.com> writes:

> s/ALIVEC/ALTIVEC/
>
> Signed-off-by: Valentin Rothberg <valentinrothberg@gmail.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/39715bf972ed4fee18fe5409609

cheers