From 6a8dff6ab16c903b0d8ef5fbf21543f39bf5d675 Mon Sep 17 00:00:00 2001 From: Markos Chandras Date: Mon, 17 Nov 2014 09:31:07 +0000 Subject: [PATCH] MIPS: tlb-r4k: Add missing HTW stop/start sequences HTW needs to stop and start again whenever the EntryHI register changes otherwise an inflight HTW operation might use the new EntryHI register for updating an old entry and that could lead to crashes or even a machine check exception. We fix this by ensuring the HTW has stop whenever the EntryHI register is about to change Signed-off-by: Markos Chandras Cc: # v3.17+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8511/ Signed-off-by: Ralf Baechle --- arch/mips/mm/tlb-r4k.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c index fa6ebd4..c3917e2 100644 --- a/arch/mips/mm/tlb-r4k.c +++ b/arch/mips/mm/tlb-r4k.c @@ -299,6 +299,7 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) local_irq_save(flags); + htw_stop(); pid = read_c0_entryhi() & ASID_MASK; address &= (PAGE_MASK << 1); write_c0_entryhi(address | pid); @@ -346,6 +347,7 @@ void __update_tlb(struct vm_area_struct * vma, unsigned long address, pte_t pte) tlb_write_indexed(); } tlbw_use_hazard(); + htw_start(); flush_itlb_vm(vma); local_irq_restore(flags); } @@ -422,6 +424,7 @@ __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1, local_irq_save(flags); /* Save old context and create impossible VPN2 value */ + htw_stop(); old_ctx = read_c0_entryhi(); old_pagemask = read_c0_pagemask(); wired = read_c0_wired(); @@ -443,6 +446,7 @@ __init int add_temporary_entry(unsigned long entrylo0, unsigned long entrylo1, write_c0_entryhi(old_ctx); write_c0_pagemask(old_pagemask); + htw_start(); out: local_irq_restore(flags); return ret; -- 2.7.4