2020-05-09 09:44:22

by Christophe Leroy

Subject: [PATCH fixes] powerpc/vdso32: Fallback on getres syscall when clock is unknown

There are other clocks than the standard ones, for instance
per process clocks. Therefore, being above the last standard clock
doesn't mean it is a bad clock. So, fallback to syscall instead
of returning -EINVAL inconditionaly.

Fixes: e33ffc956b08 ("powerpc/vdso32: implement clock_getres entirely")
Cc: [email protected]
Reported-by: Aurelien Jarno <[email protected]>
Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/vdso32/gettimeofday.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index a3951567118a..e7f8f9f1b3f4 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -218,11 +218,11 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
blr

/*
- * invalid clock
+ * syscall fallback
*/
99:
- li r3, EINVAL
- crset so
+ li r0,__NR_clock_getres
+ sc
blr
.cfi_endproc
V_FUNCTION_END(__kernel_clock_getres)
--
2.25.0

2020-05-10 22:17:58

by Aurelien Jarno

Subject: Re: [PATCH fixes] powerpc/vdso32: Fallback on getres syscall when clock is unknown

Hi,

On 2020-05-09 09:42, Christophe Leroy wrote:
> There are other clocks than the standard ones, for instance
> per process clocks. Therefore, being above the last standard clock
> doesn't mean it is a bad clock. So, fallback to syscall instead
> of returning -EINVAL inconditionaly.
>
> Fixes: e33ffc956b08 ("powerpc/vdso32: implement clock_getres entirely")
> Cc: [email protected]
> Reported-by: Aurelien Jarno <[email protected]>
> Signed-off-by: Christophe Leroy <[email protected]>
> ---
> arch/powerpc/kernel/vdso32/gettimeofday.S | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
> index a3951567118a..e7f8f9f1b3f4 100644
> --- a/arch/powerpc/kernel/vdso32/gettimeofday.S
> +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
> @@ -218,11 +218,11 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
> blr
>
> /*
> - * invalid clock
> + * syscall fallback
> */
> 99:
> - li r3, EINVAL
> - crset so
> + li r0,__NR_clock_getres
> + sc
> blr
> .cfi_endproc
> V_FUNCTION_END(__kernel_clock_getres)

Thanks a lot for the fast answer. I have just tested this patch and I
confirm it fixes the issue.

Tested-by: Aurelien Jarno <[email protected]>

--
Aurelien Jarno GPG: 4096R/1DDD8C9B
[email protected] http://www.aurel32.net

2020-05-13 20:42:35

by Michael Ellerman

Subject: Re: [PATCH fixes] powerpc/vdso32: Fallback on getres syscall when clock is unknown

On Sat, 9 May 2020 09:42:14 +0000 (UTC), Christophe Leroy wrote:
> There are other clocks than the standard ones, for instance
> per process clocks. Therefore, being above the last standard clock
> doesn't mean it is a bad clock. So, fallback to syscall instead
> of returning -EINVAL inconditionaly.

Applied to powerpc/fixes.

[1/1] powerpc/vdso32: Fallback on getres syscall when clock is unknown
https://git.kernel.org/powerpc/c/e963b7a28b2bf2416304e1a15df967fcf662aff5

cheers