cregit-Linux how code gets into the kernel

Release 4.14 arch/xtensa/include/asm/mmu_context.h

/*
 * 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);


static inline void set_rasid_register (unsigned long val) { __asm__ __volatile__ (" wsr %0, rasid\n\t" " isync\n" : : "a" (val)); }

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static inline unsigned long get_rasid_register (void) { unsigned long tmp; __asm__ __volatile__ (" rsr %0, rasid\n\t" : "=a" (tmp)); return tmp; }

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Max Filippov15.00%133.33%
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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; }

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Max Filippov3852.78%125.00%
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Adrian Bunk11.39%125.00%
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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); } }

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Adrian Bunk11.59%125.00%
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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(); }

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Adrian Bunk12.44%133.33%
Total41100.00%3100.00%

/* * 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; }

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Total49100.00%2100.00%


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); }

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Max Filippov3649.32%125.00%
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Adrian Bunk11.37%125.00%
Total73100.00%4100.00%

#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(); }

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static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk) { /* Nothing to do. */ }

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#endif /* CONFIG_MMU */ #endif /* _XTENSA_MMU_CONTEXT_H */

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Johannes Weiner132.68%218.18%
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Jeremy Fitzhardinge30.62%19.09%
Ingo Molnar30.62%19.09%
Total485100.00%11100.00%
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