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powerpc/e6500: hw tablewalk: fix recursive tlb lock on cpu 0

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Commit 82d86de25b "TLB lock recursive"
introduced a bug whereby cpu 0 uses the same value for "lock held" as
is used to indicate that the lock is free.  This means that cpu 1 can
acquire the lock whenever it wants, regardless of whether cpu 0 has it
locked, which in turn means we can get duplicate TLB entries.

Add one to the CPU value to ensure we do not use zero as a "lock held"
value.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Reported-by: Ed Swarthout <ed.swarthout@freescale.com>
This commit is contained in:
Scott Wood 2014-05-22 16:10:35 -05:00
parent bbd08c72c6
commit 1cb4ed92f6
1 changed files with 2 additions and 1 deletions
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3
arch/powerpc/mm/tlb_low_64e.S
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@ -296,7 +296,7 @@ itlb_miss_fault_bolted:
* r14 = page table base
* r13 = PACA
* r11 = tlb_per_core ptr
* r10 = cpu number
* r10 = crap (free to use)
*/
tlb_miss_common_e6500:
/*
@ -309,6 +309,7 @@ tlb_miss_common_e6500:
lhz r10,PACAPACAINDEX(r13)
cmpdi r15,0
cmpdi cr1,r15,1 /* set cr1.eq = 0 for non-recursive */
addi r10,r10,1
bne 2f
stbcx. r10,0,r11
bne 1b