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: 012838923db6 ("powerpc/vdso32: implement clock_getres entirely")
Cc: stable@vger.kernel.org # v5.6+
Reported-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Link: https://lore.kernel.org/r/7316a9e2c0c2517923eb4b0411c4a08d15e675a4.1589017281.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index a3951567118a9bbabd256ea418e57b346cc5c1a7..e7f8f9f1b3f46ba3da4b84fc3c44eb2560f91b96 100644 (file)
--- 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)