[PATCH 5.6 154/194] powerpc/vdso32: Fallback on getres syscall when clock is unknown

[Greg Kroah-Hartman]

From: Christophe Leroy <christophe.leroy@xxxxxxxxxx>

commit e963b7a28b2bf2416304e1a15df967fcf662aff5 upstream.

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: stable@xxxxxxxxxxxxxxx # v5.6+
Reported-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Tested-by: Aurelien Jarno <aurelien@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/7316a9e2c0c2517923eb4b0411c4a08d15e675a4.1589017281.git.christophe.leroy@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/powerpc/kernel/vdso32/gettimeofday.S |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- 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)