From 1cb4ed92f6a5a8961b122d11e651870ba741245b Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Thu, 22 May 2014 16:10:35 -0500 Subject: [PATCH] powerpc/e6500: hw tablewalk: fix recursive tlb lock on cpu 0 Commit 82d86de25b9c99db546e17c6f7ebf9a691da557e "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 Reported-by: Ed Swarthout --- arch/powerpc/mm/tlb_low_64e.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S index 3298d1039e80..131f1f412bdd 100644 --- a/arch/powerpc/mm/tlb_low_64e.S +++ b/arch/powerpc/mm/tlb_low_64e.S @@ -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 -- GitLab