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| author | John David Anglin <dave.anglin@bell.net> | 2013-01-14 19:45:00 -0500 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-03-06 03:23:44 +0000 |
| commit | 0af31617ad5cf724312c90f78ed95cb6988c3d6f (patch) | |
| tree | b953bc049b4ad671cf4cf27bf903cb22c30e5d7a /arch/parisc | |
| parent | 26d9655e02f35f47c2d2fd026dcd19a7d0b233cd (diff) | |
| download | lwn-0af31617ad5cf724312c90f78ed95cb6988c3d6f.tar.gz lwn-0af31617ad5cf724312c90f78ed95cb6988c3d6f.zip | |
Purge existing TLB entries in set_pte_at and ptep_set_wrprotect
commit 7139bc1579901b53db7e898789e916ee2fb52d78 upstream.
This patch goes a long way toward fixing the minifail bug, and
it significantly improves the stability of SMP machines such as
the rp3440. When write protecting a page for COW, we need to
purge the existing translation. Otherwise, the COW break
doesn't occur as expected because the TLB may still have a stale entry
which allows writes.
[jejb: fix up checkpatch errors]
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'arch/parisc')
| -rw-r--r-- | arch/parisc/include/asm/pgtable.h | 13 | ||||
| -rw-r--r-- | arch/parisc/kernel/cache.c | 18 |
2 files changed, 28 insertions, 3 deletions
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h index 22dadeb58695..9d35a3eac24f 100644 --- a/arch/parisc/include/asm/pgtable.h +++ b/arch/parisc/include/asm/pgtable.h @@ -12,11 +12,10 @@ #include <linux/bitops.h> #include <linux/spinlock.h> +#include <linux/mm_types.h> #include <asm/processor.h> #include <asm/cache.h> -struct vm_area_struct; - /* * kern_addr_valid(ADDR) tests if ADDR is pointing to valid kernel * memory. For the return value to be meaningful, ADDR must be >= @@ -40,7 +39,14 @@ struct vm_area_struct; do{ \ *(pteptr) = (pteval); \ } while(0) -#define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval) + +extern void purge_tlb_entries(struct mm_struct *, unsigned long); + +#define set_pte_at(mm, addr, ptep, pteval) \ + do { \ + set_pte(ptep, pteval); \ + purge_tlb_entries(mm, addr); \ + } while (0) #endif /* !__ASSEMBLY__ */ @@ -464,6 +470,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, old = pte_val(*ptep); new = pte_val(pte_wrprotect(__pte (old))); } while (cmpxchg((unsigned long *) ptep, old, new) != old); + purge_tlb_entries(mm, addr); #else pte_t old_pte = *ptep; set_pte_at(mm, addr, ptep, pte_wrprotect(old_pte)); diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index 83335f3da5fc..5241698ede66 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -421,6 +421,24 @@ void kunmap_parisc(void *addr) EXPORT_SYMBOL(kunmap_parisc); #endif +void purge_tlb_entries(struct mm_struct *mm, unsigned long addr) +{ + unsigned long flags; + + /* Note: purge_tlb_entries can be called at startup with + no context. */ + + /* Disable preemption while we play with %sr1. */ + preempt_disable(); + mtsp(mm->context, 1); + purge_tlb_start(flags); + pdtlb(addr); + pitlb(addr); + purge_tlb_end(flags); + preempt_enable(); +} +EXPORT_SYMBOL(purge_tlb_entries); + void __flush_tlb_range(unsigned long sid, unsigned long start, unsigned long end) { |