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

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Date:   Sat,  9 May 2020 09:42:14 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Aurelien Jarno <aurelien@...el32.net>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
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: stable@...r.kernel.org
Reported-by: Aurelien Jarno <aurelien@...el32.net>
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 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