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Diffstat (limited to 'arch/xtensa/include/asm/mmu_context.h')
| -rw-r--r-- | arch/xtensa/include/asm/mmu_context.h | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/mmu_context.h b/arch/xtensa/include/asm/mmu_context.h new file mode 100644 index 000000000..de5e6cbba --- /dev/null +++ b/arch/xtensa/include/asm/mmu_context.h @@ -0,0 +1,159 @@ +/* + * Switch an 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) 2001 - 2013 Tensilica Inc. + */ + +#ifndef _XTENSA_MMU_CONTEXT_H +#define _XTENSA_MMU_CONTEXT_H + +#ifndef CONFIG_MMU +#include <asm/nommu_context.h> +#else + +#include <linux/stringify.h> +#include <linux/sched.h> +#include <linux/mm_types.h> + +#include <asm/vectors.h> + +#include <asm/pgtable.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm-generic/mm_hooks.h> +#include <asm-generic/percpu.h> + +#if (XCHAL_HAVE_TLBS != 1) +# error "Linux must have an MMU!" +#endif + +DECLARE_PER_CPU(unsigned long, asid_cache); +#define cpu_asid_cache(cpu) per_cpu(asid_cache, cpu) + +/* + * NO_CONTEXT is the invalid ASID value that we don't ever assign to + * any user or kernel context. We use the reserved values in the + * ASID_INSERT macro below. + * + * 0 invalid + * 1 kernel + * 2 reserved + * 3 reserved + * 4...255 available + */ + +#define NO_CONTEXT 0 +#define ASID_USER_FIRST 4 +#define ASID_MASK ((1 << XCHAL_MMU_ASID_BITS) - 1) +#define ASID_INSERT(x) (0x03020001 | (((x) & ASID_MASK) << 8)) + +void init_mmu(void); +void init_kio(void); + +static inline void set_rasid_register (unsigned long val) +{ + __asm__ __volatile__ (" wsr %0, rasid\n\t" + " isync\n" : : "a" (val)); +} + +static inline unsigned long get_rasid_register (void) +{ + unsigned long tmp; + __asm__ __volatile__ (" rsr %0, rasid\n\t" : "=a" (tmp)); + return tmp; +} + +static inline void get_new_mmu_context(struct mm_struct *mm, unsigned int cpu) +{ + unsigned long asid = cpu_asid_cache(cpu); + if ((++asid & ASID_MASK) == 0) { + /* + * Start new asid cycle; continue counting with next + * incarnation bits; skipping over 0, 1, 2, 3. + */ + local_flush_tlb_all(); + asid += ASID_USER_FIRST; + } + cpu_asid_cache(cpu) = asid; + mm->context.asid[cpu] = asid; + mm->context.cpu = cpu; +} + +static inline void get_mmu_context(struct mm_struct *mm, unsigned int cpu) +{ + /* + * Check if our ASID is of an older version and thus invalid. + */ + + if (mm) { + unsigned long asid = mm->context.asid[cpu]; + + if (asid == NO_CONTEXT || + ((asid ^ cpu_asid_cache(cpu)) & ~ASID_MASK)) + get_new_mmu_context(mm, cpu); + } +} + +static inline void activate_context(struct mm_struct *mm, unsigned int cpu) +{ + get_mmu_context(mm, cpu); + set_rasid_register(ASID_INSERT(mm->context.asid[cpu])); + invalidate_page_directory(); +} + +/* + * Initialize the context related info for a new mm_struct + * instance. Valid cpu values are 0..(NR_CPUS-1), so initializing + * to -1 says the process has never run on any core. + */ + +static inline int init_new_context(struct task_struct *tsk, + struct mm_struct *mm) +{ + int cpu; + for_each_possible_cpu(cpu) { + mm->context.asid[cpu] = NO_CONTEXT; + } + mm->context.cpu = -1; + 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(); + int migrated = next->context.cpu != cpu; + /* Flush the icache if we migrated to a new core. */ + if (migrated) { + __invalidate_icache_all(); + next->context.cpu = cpu; + } + if (migrated || prev != next) + activate_context(next, cpu); +} + +#define activate_mm(prev, next) switch_mm((prev), (next), NULL) +#define deactivate_mm(tsk, mm) do { } while (0) + +/* + * 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) +{ + invalidate_page_directory(); +} + + +static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) +{ + /* Nothing to do. */ + +} + +#endif /* CONFIG_MMU */ +#endif /* _XTENSA_MMU_CONTEXT_H */ |