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powerpc/e6500: hw tablewalk: optimize a bit for tcd lock acquiring codes 

It makes no sense to put the instructions for calculating the lock
value (cpu number + 1) and the clearing of eq bit of cr1 in lbarx/stbcx
loop. And when the lock is acquired by the other thread, the current
lock value has no chance to equal with the lock value used by current
cpu. So we can skip the comparing for these two lock values in the
lbz/bne loop.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
This commit is contained in:
Kevin Hao 2015-08-13 19:51:36 +08:00 committed by Scott Wood
parent e5e55cc08c
commit 69399ee9cb
1 changed files with 5 additions and 5 deletions
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10
arch/powerpc/mm/tlb_low_64e.S
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@ -308,11 +308,11 @@ BEGIN_FTR_SECTION /* CPU_FTR_SMT */
*
* MAS6:IND should be already set based on MAS4
*/
1: lbarx r15,0,r11
lhz r10,PACAPACAINDEX(r13)
cmpdi r15,0
cmpdi cr1,r15,1 /* set cr1.eq = 0 for non-recursive */
addi r10,r10,1
crclr cr1*4+eq /* set cr1.eq = 0 for non-recursive */
1: lbarx r15,0,r11
cmpdi r15,0
bne 2f
stbcx. r10,0,r11
bne 1b
@ -320,9 +320,9 @@ BEGIN_FTR_SECTION /* CPU_FTR_SMT */
.subsection 1
2: cmpd cr1,r15,r10 /* recursive lock due to mcheck/crit/etc? */
beq cr1,3b /* unlock will happen if cr1.eq = 0 */
lbz r15,0(r11)
10: lbz r15,0(r11)
cmpdi r15,0
bne 2b
bne 10b
b 1b
.previous