linux-kernel - [PATCH v2 7/8] powerpc/vdso32: implement clock

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Date:   Thu, 22 Aug 2019 16:34:08 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v2 7/8] powerpc/vdso32: implement clock_getres entirely

clock_getres returns hrtimer_res for all clocks but coarse ones
for which it returns KTIME_LOW_RES.

return EINVAL for unknown clocks.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/asm-offsets.c         |  3 +++
 arch/powerpc/kernel/vdso32/gettimeofday.S | 19 +++++++++++--------
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index b6328a90cad7..dbfd3ddc85dc 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -417,7 +417,10 @@ int main(void)
 	DEFINE(CLOCK_MONOTONIC, CLOCK_MONOTONIC);
 	DEFINE(CLOCK_REALTIME_COARSE, CLOCK_REALTIME_COARSE);
 	DEFINE(CLOCK_MONOTONIC_COARSE, CLOCK_MONOTONIC_COARSE);
+	DEFINE(CLOCK_MAX, CLOCK_TAI);
 	DEFINE(NSEC_PER_SEC, NSEC_PER_SEC);
+	DEFINE(EINVAL, EINVAL);
+	DEFINE(KTIME_LOW_RES, KTIME_LOW_RES);
 
 #ifdef CONFIG_BUG
 	DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry));
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index 0f87be0ebf7e..c65f41c612f7 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -199,17 +199,20 @@ V_FUNCTION_END(__kernel_clock_gettime)
 V_FUNCTION_BEGIN(__kernel_clock_getres)
   .cfi_startproc
 	/* Check for supported clock IDs */
-	cmpwi	cr0,r3,CLOCK_REALTIME
-	cmpwi	cr1,r3,CLOCK_MONOTONIC
-	cror	cr0*4+eq,cr0*4+eq,cr1*4+eq
-	bne	cr0,99f
+	cmplwi	cr0, r3, CLOCK_MAX
+	cmpwi	cr1, r3, CLOCK_REALTIME_COARSE
+	cmpwi	cr7, r3, CLOCK_MONOTONIC_COARSE
+	bgt	cr0, 99f
+	LOAD_REG_IMMEDIATE(r5, KTIME_LOW_RES)
+	beq	cr1, 1f
+	beq	cr7, 1f
 
 	mflr	r12
   .cfi_register lr,r12
 	get_datapage	r3, r0
 	lwz	r5, CLOCK_HRTIMER_RES(r3)
 	mtlr	r12
-	li	r3,0
+1:	li	r3,0
 	cmpli	cr0,r4,0
 	crclr	cr0*4+so
 	beqlr
@@ -218,11 +221,11 @@ V_FUNCTION_BEGIN(__kernel_clock_getres)
 	blr
 
 	/*
-	 * syscall fallback
+	 * invalid clock
 	 */
 99:
-	li	r0,__NR_clock_getres
-	sc
+	li	r3, EINVAL
+	crset	so
 	blr
   .cfi_endproc
 V_FUNCTION_END(__kernel_clock_getres)
-- 
2.13.3