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Date: Tue, 26 Feb 2013 15:58:06 -0800 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, John David Anglin <dave.anglin@...l.net>, James Bottomley <JBottomley@...allels.com> Subject: [ 37/53] [PARISC] Purge existing TLB entries in set_pte_at and ptep_set_wrprotect 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: John David Anglin <dave.anglin@...l.net> 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@...l.net> Signed-off-by: James Bottomley <JBottomley@...allels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- arch/parisc/include/asm/pgtable.h | 13 ++++++++++--- arch/parisc/kernel/cache.c | 18 ++++++++++++++++++ 2 files changed, 28 insertions(+), 3 deletions(-) --- 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(st 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)); --- 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) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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