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https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
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d6dd61c831
Add hooks to allow a paravirt implementation to track the lifetime of an mm. Paravirtualization requires three hooks, but only two are needed in common code. They are: arch_dup_mmap, which is called when a new mmap is created at fork arch_exit_mmap, which is called when the last process reference to an mm is dropped, which typically happens on exit and exec. The third hook is activate_mm, which is called from the arch-specific activate_mm() macro/function, and so doesn't need stub versions for other architectures. It's called when an mm is first used. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: linux-arch@vger.kernel.org Cc: James Bottomley <James.Bottomley@SteelEye.com> Acked-by: Ingo Molnar <mingo@elte.hu>
298 lines
8.1 KiB
C
298 lines
8.1 KiB
C
/*
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* Switch a MMU context.
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle
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* Copyright (C) 1999 Silicon Graphics, Inc.
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*/
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#ifndef _ASM_MMU_CONTEXT_H
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#define _ASM_MMU_CONTEXT_H
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#include <linux/errno.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#ifdef CONFIG_MIPS_MT_SMTC
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#include <asm/mipsmtregs.h>
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#include <asm/smtc.h>
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#endif /* SMTC */
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#include <asm-generic/mm_hooks.h>
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/*
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* For the fast tlb miss handlers, we keep a per cpu array of pointers
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* to the current pgd for each processor. Also, the proc. id is stuffed
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* into the context register.
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*/
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extern unsigned long pgd_current[];
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#define TLBMISS_HANDLER_SETUP_PGD(pgd) \
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pgd_current[smp_processor_id()] = (unsigned long)(pgd)
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#ifdef CONFIG_32BIT
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#define TLBMISS_HANDLER_SETUP() \
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write_c0_context((unsigned long) smp_processor_id() << 25); \
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TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
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#endif
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#ifdef CONFIG_64BIT
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#define TLBMISS_HANDLER_SETUP() \
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write_c0_context((unsigned long) smp_processor_id() << 26); \
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TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
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#endif
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#if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
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#define ASID_INC 0x40
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#define ASID_MASK 0xfc0
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#elif defined(CONFIG_CPU_R8000)
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#define ASID_INC 0x10
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#define ASID_MASK 0xff0
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#elif defined(CONFIG_CPU_RM9000)
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#define ASID_INC 0x1
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#define ASID_MASK 0xfff
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/* SMTC/34K debug hack - but maybe we'll keep it */
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#elif defined(CONFIG_MIPS_MT_SMTC)
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#define ASID_INC 0x1
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extern unsigned long smtc_asid_mask;
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#define ASID_MASK (smtc_asid_mask)
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#define HW_ASID_MASK 0xff
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/* End SMTC/34K debug hack */
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#else /* FIXME: not correct for R6000 */
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#define ASID_INC 0x1
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#define ASID_MASK 0xff
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#endif
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#define cpu_context(cpu, mm) ((mm)->context[cpu])
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#define cpu_asid(cpu, mm) (cpu_context((cpu), (mm)) & ASID_MASK)
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#define asid_cache(cpu) (cpu_data[cpu].asid_cache)
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static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
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{
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}
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/*
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* All unused by hardware upper bits will be considered
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* as a software asid extension.
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*/
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#define ASID_VERSION_MASK ((unsigned long)~(ASID_MASK|(ASID_MASK-1)))
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#define ASID_FIRST_VERSION ((unsigned long)(~ASID_VERSION_MASK) + 1)
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#ifndef CONFIG_MIPS_MT_SMTC
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/* Normal, classic MIPS get_new_mmu_context */
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static inline void
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get_new_mmu_context(struct mm_struct *mm, unsigned long cpu)
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{
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unsigned long asid = asid_cache(cpu);
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if (! ((asid += ASID_INC) & ASID_MASK) ) {
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if (cpu_has_vtag_icache)
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flush_icache_all();
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local_flush_tlb_all(); /* start new asid cycle */
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if (!asid) /* fix version if needed */
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asid = ASID_FIRST_VERSION;
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}
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cpu_context(cpu, mm) = asid_cache(cpu) = asid;
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}
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#else /* CONFIG_MIPS_MT_SMTC */
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#define get_new_mmu_context(mm,cpu) smtc_get_new_mmu_context((mm),(cpu))
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#endif /* CONFIG_MIPS_MT_SMTC */
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/*
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* Initialize the context related info for a new mm_struct
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* instance.
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*/
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static inline int
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init_new_context(struct task_struct *tsk, struct mm_struct *mm)
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{
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int i;
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for (i = 0; i < num_online_cpus(); i++)
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cpu_context(i, mm) = 0;
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return 0;
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}
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static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
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struct task_struct *tsk)
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{
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unsigned int cpu = smp_processor_id();
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unsigned long flags;
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#ifdef CONFIG_MIPS_MT_SMTC
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unsigned long oldasid;
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unsigned long mtflags;
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int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
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local_irq_save(flags);
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mtflags = dvpe();
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#else /* Not SMTC */
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local_irq_save(flags);
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#endif /* CONFIG_MIPS_MT_SMTC */
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/* Check if our ASID is of an older version and thus invalid */
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if ((cpu_context(cpu, next) ^ asid_cache(cpu)) & ASID_VERSION_MASK)
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get_new_mmu_context(next, cpu);
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#ifdef CONFIG_MIPS_MT_SMTC
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/*
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* If the EntryHi ASID being replaced happens to be
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* the value flagged at ASID recycling time as having
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* an extended life, clear the bit showing it being
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* in use by this "CPU", and if that's the last bit,
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* free up the ASID value for use and flush any old
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* instances of it from the TLB.
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*/
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oldasid = (read_c0_entryhi() & ASID_MASK);
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if(smtc_live_asid[mytlb][oldasid]) {
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smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
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if(smtc_live_asid[mytlb][oldasid] == 0)
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smtc_flush_tlb_asid(oldasid);
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}
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/*
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* Tread softly on EntryHi, and so long as we support
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* having ASID_MASK smaller than the hardware maximum,
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* make sure no "soft" bits become "hard"...
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*/
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write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
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| (cpu_context(cpu, next) & ASID_MASK));
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ehb(); /* Make sure it propagates to TCStatus */
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evpe(mtflags);
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#else
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write_c0_entryhi(cpu_context(cpu, next));
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#endif /* CONFIG_MIPS_MT_SMTC */
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TLBMISS_HANDLER_SETUP_PGD(next->pgd);
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/*
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* Mark current->active_mm as not "active" anymore.
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* We don't want to mislead possible IPI tlb flush routines.
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*/
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cpu_clear(cpu, prev->cpu_vm_mask);
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cpu_set(cpu, next->cpu_vm_mask);
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local_irq_restore(flags);
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}
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/*
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* Destroy context related info for an mm_struct that is about
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* to be put to rest.
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*/
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static inline void destroy_context(struct mm_struct *mm)
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{
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}
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#define deactivate_mm(tsk,mm) do { } while (0)
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/*
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* After we have set current->mm to a new value, this activates
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* the context for the new mm so we see the new mappings.
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*/
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static inline void
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activate_mm(struct mm_struct *prev, struct mm_struct *next)
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{
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unsigned long flags;
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unsigned int cpu = smp_processor_id();
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#ifdef CONFIG_MIPS_MT_SMTC
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unsigned long oldasid;
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unsigned long mtflags;
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int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
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#endif /* CONFIG_MIPS_MT_SMTC */
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local_irq_save(flags);
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/* Unconditionally get a new ASID. */
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get_new_mmu_context(next, cpu);
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#ifdef CONFIG_MIPS_MT_SMTC
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/* See comments for similar code above */
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mtflags = dvpe();
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oldasid = read_c0_entryhi() & ASID_MASK;
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if(smtc_live_asid[mytlb][oldasid]) {
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smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
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if(smtc_live_asid[mytlb][oldasid] == 0)
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smtc_flush_tlb_asid(oldasid);
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}
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/* See comments for similar code above */
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write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK) |
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(cpu_context(cpu, next) & ASID_MASK));
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ehb(); /* Make sure it propagates to TCStatus */
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evpe(mtflags);
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#else
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write_c0_entryhi(cpu_context(cpu, next));
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#endif /* CONFIG_MIPS_MT_SMTC */
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TLBMISS_HANDLER_SETUP_PGD(next->pgd);
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/* mark mmu ownership change */
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cpu_clear(cpu, prev->cpu_vm_mask);
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cpu_set(cpu, next->cpu_vm_mask);
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local_irq_restore(flags);
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}
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/*
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* If mm is currently active_mm, we can't really drop it. Instead,
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* we will get a new one for it.
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*/
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static inline void
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drop_mmu_context(struct mm_struct *mm, unsigned cpu)
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{
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unsigned long flags;
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#ifdef CONFIG_MIPS_MT_SMTC
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unsigned long oldasid;
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/* Can't use spinlock because called from TLB flush within DVPE */
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unsigned int prevvpe;
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int mytlb = (smtc_status & SMTC_TLB_SHARED) ? 0 : cpu_data[cpu].vpe_id;
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#endif /* CONFIG_MIPS_MT_SMTC */
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local_irq_save(flags);
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if (cpu_isset(cpu, mm->cpu_vm_mask)) {
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get_new_mmu_context(mm, cpu);
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#ifdef CONFIG_MIPS_MT_SMTC
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/* See comments for similar code above */
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prevvpe = dvpe();
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oldasid = (read_c0_entryhi() & ASID_MASK);
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if (smtc_live_asid[mytlb][oldasid]) {
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smtc_live_asid[mytlb][oldasid] &= ~(0x1 << cpu);
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if(smtc_live_asid[mytlb][oldasid] == 0)
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smtc_flush_tlb_asid(oldasid);
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}
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/* See comments for similar code above */
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write_c0_entryhi((read_c0_entryhi() & ~HW_ASID_MASK)
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| cpu_asid(cpu, mm));
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ehb(); /* Make sure it propagates to TCStatus */
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evpe(prevvpe);
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#else /* not CONFIG_MIPS_MT_SMTC */
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write_c0_entryhi(cpu_asid(cpu, mm));
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#endif /* CONFIG_MIPS_MT_SMTC */
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} else {
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/* will get a new context next time */
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#ifndef CONFIG_MIPS_MT_SMTC
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cpu_context(cpu, mm) = 0;
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#else /* SMTC */
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int i;
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/* SMTC shares the TLB (and ASIDs) across VPEs */
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for (i = 0; i < num_online_cpus(); i++) {
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if((smtc_status & SMTC_TLB_SHARED)
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|| (cpu_data[i].vpe_id == cpu_data[cpu].vpe_id))
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cpu_context(i, mm) = 0;
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}
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#endif /* CONFIG_MIPS_MT_SMTC */
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}
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local_irq_restore(flags);
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}
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#endif /* _ASM_MMU_CONTEXT_H */
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