From e8d8fc219f9a0e63e7fb927881e6f4db8e7d34df Mon Sep 17 00:00:00 2001 From: John David Anglin Date: Sat, 29 Jun 2013 16:42:12 -0400 Subject: [PATCH] parisc: Ensure volatile space register %sr1 is not clobbered I still see the occasional random segv on rp3440. Looking at one of these (a code 15), it appeared the problem must be with the cache handling of anonymous pages. Reviewing this, I noticed that the space register %sr1 might be being clobbered when we flush an anonymous page. Register %sr1 is used for TLB purges in a couple of places. These purges are needed on PA8800 and PA8900 processors to ensure cache consistency of flushed cache lines. The solution here is simply to move the %sr1 load into the TLB lock region needed to ensure that one purge executes at a time on SMP systems. This was already the case for one use. After a few days of operation, I haven't had a random segv on my rp3440. Signed-off-by: John David Anglin Cc: # 3.10 Signed-off-by: Helge Deller --- arch/parisc/include/asm/tlbflush.h | 5 +++-- arch/parisc/kernel/cache.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/parisc/include/asm/tlbflush.h b/arch/parisc/include/asm/tlbflush.h index 5273da991e06..9d086a599fa0 100644 --- a/arch/parisc/include/asm/tlbflush.h +++ b/arch/parisc/include/asm/tlbflush.h @@ -63,13 +63,14 @@ static inline void flush_tlb_mm(struct mm_struct *mm) static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) { - unsigned long flags; + unsigned long flags, sid; /* For one page, it's not worth testing the split_tlb variable */ mb(); - mtsp(vma->vm_mm->context,1); + sid = vma->vm_mm->context; purge_tlb_start(flags); + mtsp(sid, 1); pdtlb(addr); pitlb(addr); purge_tlb_end(flags); diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index 65fb4cbc3a0f..2e65aa54bd10 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -440,8 +440,8 @@ void __flush_tlb_range(unsigned long sid, unsigned long start, else { unsigned long flags; - mtsp(sid, 1); purge_tlb_start(flags); + mtsp(sid, 1); if (split_tlb) { while (npages--) { pdtlb(start);