Re: [PATCH 1/2] powerpc/vdso64: Coarse timer support preparatory patch

Thanks for reviewing Naveen.

"Naveen N. Rao" [off-list ref] writes:

On 2017/09/18 09:23AM, Santosh Sivaraj wrote:

quoted

diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S
index 382021324883..a0b4943811db 100644
--- a/arch/powerpc/kernel/vdso64/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso64/gettimeofday.S

@@ -60,18 +60,20 @@ V_FUNCTION_END(__kernel_gettimeofday)
  */
 V_FUNCTION_BEGIN(__kernel_clock_gettime)
   .cfi_startproc
+	mr	r11,r4			/* r11 saves tp */
+	mflr	r12			/* r12 saves lr */
+	lis	r7,NSEC_PER_SEC@h	/* want nanoseconds */
+	ori	r7,r7,NSEC_PER_SEC@l
+
 	/* 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
+	beq	cr0,49f

-	mflr	r12			/* r12 saves lr */
+	b	99f		/* Fallback to syscall */

'beq', followed by a 'b' looks weird without considering the next patch.  
I think this can be organized better to not have to update r7/r11/r12 if 
using the system call. See next patch for my comments.

quoted

   .cfi_register lr,r12

If you move the mflr, you should move the above line along with it.

s/should/must/.

It literally says "lr is saved in r12".

cheers