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linux-next/arch/xtensa/include/asm/mmu_context.h
Max Filippov c2edb35ae3 xtensa: extract init_kio
KIO region placement may be specified in the device tree, that's why
it's initialized with the rest of MMU after the early_init_devtree. In
order to support KASAN the MMU must be initialized earlier.
Separate KIO initialization from the rest of MMU initialization.
Reinitialize KIO if its location is specified in the device tree.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2017-12-16 22:37:10 -08:00

160 lines
3.6 KiB
C

/*
* 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 */