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| -rw-r--r-- | arch/mips/include/asm/mmu_context.h | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h new file mode 100644 index 000000000..cddead91a --- /dev/null +++ b/arch/mips/include/asm/mmu_context.h @@ -0,0 +1,240 @@ +/* + * Switch a MMU context. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1996, 1997, 1998, 1999 by Ralf Baechle + * Copyright (C) 1999 Silicon Graphics, Inc. + */ +#ifndef _ASM_MMU_CONTEXT_H +#define _ASM_MMU_CONTEXT_H + +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/mm_types.h> +#include <linux/smp.h> +#include <linux/slab.h> + +#include <asm/barrier.h> +#include <asm/cacheflush.h> +#include <asm/dsemul.h> +#include <asm/ginvt.h> +#include <asm/hazards.h> +#include <asm/tlbflush.h> +#include <asm-generic/mm_hooks.h> + +#define htw_set_pwbase(pgd) \ +do { \ + if (cpu_has_htw) { \ + write_c0_pwbase(pgd); \ + back_to_back_c0_hazard(); \ + } \ +} while (0) + +extern void tlbmiss_handler_setup_pgd(unsigned long); +extern char tlbmiss_handler_setup_pgd_end[]; + +/* Note: This is also implemented with uasm in arch/mips/kvm/entry.c */ +#define TLBMISS_HANDLER_SETUP_PGD(pgd) \ +do { \ + tlbmiss_handler_setup_pgd((unsigned long)(pgd)); \ + htw_set_pwbase((unsigned long)pgd); \ +} while (0) + +#ifdef CONFIG_MIPS_PGD_C0_CONTEXT + +#define TLBMISS_HANDLER_RESTORE() \ + write_c0_xcontext((unsigned long) smp_processor_id() << \ + SMP_CPUID_REGSHIFT) + +#define TLBMISS_HANDLER_SETUP() \ + do { \ + TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); \ + TLBMISS_HANDLER_RESTORE(); \ + } while (0) + +#else /* !CONFIG_MIPS_PGD_C0_CONTEXT: using pgd_current*/ + +/* + * For the fast tlb miss handlers, we keep a per cpu array of pointers + * to the current pgd for each processor. Also, the proc. id is stuffed + * into the context register. + */ +extern unsigned long pgd_current[]; + +#define TLBMISS_HANDLER_RESTORE() \ + write_c0_context((unsigned long) smp_processor_id() << \ + SMP_CPUID_REGSHIFT) + +#define TLBMISS_HANDLER_SETUP() \ + TLBMISS_HANDLER_RESTORE(); \ + back_to_back_c0_hazard(); \ + TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir) +#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/ + +/* + * The ginvt instruction will invalidate wired entries when its type field + * targets anything other than the entire TLB. That means that if we were to + * allow the kernel to create wired entries with the MMID of current->active_mm + * then those wired entries could be invalidated when we later use ginvt to + * invalidate TLB entries with that MMID. + * + * In order to prevent ginvt from trashing wired entries, we reserve one MMID + * for use by the kernel when creating wired entries. This MMID will never be + * assigned to a struct mm, and we'll never target it with a ginvt instruction. + */ +#define MMID_KERNEL_WIRED 0 + +/* + * All unused by hardware upper bits will be considered + * as a software asid extension. + */ +static inline u64 asid_version_mask(unsigned int cpu) +{ + unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]); + + return ~(u64)(asid_mask | (asid_mask - 1)); +} + +static inline u64 asid_first_version(unsigned int cpu) +{ + return ~asid_version_mask(cpu) + 1; +} + +static inline u64 cpu_context(unsigned int cpu, const struct mm_struct *mm) +{ + if (cpu_has_mmid) + return atomic64_read(&mm->context.mmid); + + return mm->context.asid[cpu]; +} + +static inline void set_cpu_context(unsigned int cpu, + struct mm_struct *mm, u64 ctx) +{ + if (cpu_has_mmid) + atomic64_set(&mm->context.mmid, ctx); + else + mm->context.asid[cpu] = ctx; +} + +#define asid_cache(cpu) (cpu_data[cpu].asid_cache) +#define cpu_asid(cpu, mm) \ + (cpu_context((cpu), (mm)) & cpu_asid_mask(&cpu_data[cpu])) + +static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ +} + +extern void get_new_mmu_context(struct mm_struct *mm); +extern void check_mmu_context(struct mm_struct *mm); +extern void check_switch_mmu_context(struct mm_struct *mm); + +/* + * Initialize the context related info for a new mm_struct + * instance. + */ +static inline int +init_new_context(struct task_struct *tsk, struct mm_struct *mm) +{ + int i; + + if (cpu_has_mmid) { + set_cpu_context(0, mm, 0); + } else { + for_each_possible_cpu(i) + set_cpu_context(i, mm, 0); + } + + mm->context.bd_emupage_allocmap = NULL; + spin_lock_init(&mm->context.bd_emupage_lock); + init_waitqueue_head(&mm->context.bd_emupage_queue); + + return 0; +} + +static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, + struct task_struct *tsk) +{ + unsigned int cpu = smp_processor_id(); + unsigned long flags; + local_irq_save(flags); + + htw_stop(); + check_switch_mmu_context(next); + + /* + * Mark current->active_mm as not "active" anymore. + * We don't want to mislead possible IPI tlb flush routines. + */ + cpumask_clear_cpu(cpu, mm_cpumask(prev)); + cpumask_set_cpu(cpu, mm_cpumask(next)); + htw_start(); + + local_irq_restore(flags); +} + +/* + * Destroy context related info for an mm_struct that is about + * to be put to rest. + */ +static inline void destroy_context(struct mm_struct *mm) +{ + dsemul_mm_cleanup(mm); +} + +#define activate_mm(prev, next) switch_mm(prev, next, current) +#define deactivate_mm(tsk, mm) do { } while (0) + +static inline void +drop_mmu_context(struct mm_struct *mm) +{ + unsigned long flags; + unsigned int cpu; + u32 old_mmid; + u64 ctx; + + local_irq_save(flags); + + cpu = smp_processor_id(); + ctx = cpu_context(cpu, mm); + + if (!ctx) { + /* no-op */ + } else if (cpu_has_mmid) { + /* + * Globally invalidating TLB entries associated with the MMID + * is pretty cheap using the GINVT instruction, so we'll do + * that rather than incur the overhead of allocating a new + * MMID. The latter would be especially difficult since MMIDs + * are global & other CPUs may be actively using ctx. + */ + htw_stop(); + old_mmid = read_c0_memorymapid(); + write_c0_memorymapid(ctx & cpu_asid_mask(&cpu_data[cpu])); + mtc0_tlbw_hazard(); + ginvt_mmid(); + sync_ginv(); + write_c0_memorymapid(old_mmid); + instruction_hazard(); + htw_start(); + } else if (cpumask_test_cpu(cpu, mm_cpumask(mm))) { + /* + * mm is currently active, so we can't really drop it. + * Instead we bump the ASID. + */ + htw_stop(); + get_new_mmu_context(mm); + write_c0_entryhi(cpu_asid(cpu, mm)); + htw_start(); + } else { + /* will get a new context next time */ + set_cpu_context(cpu, mm, 0); + } + + local_irq_restore(flags); +} + +#endif /* _ASM_MMU_CONTEXT_H */ |