162 строки
4.0 KiB
C
162 строки
4.0 KiB
C
/*
|
|
* Based on arch/arm/include/asm/mmu_context.h
|
|
*
|
|
* Copyright (C) 1996 Russell King.
|
|
* Copyright (C) 2012 ARM Ltd.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#ifndef __ASM_MMU_CONTEXT_H
|
|
#define __ASM_MMU_CONTEXT_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/sched.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/proc-fns.h>
|
|
#include <asm-generic/mm_hooks.h>
|
|
#include <asm/cputype.h>
|
|
#include <asm/pgtable.h>
|
|
|
|
#define MAX_ASID_BITS 16
|
|
|
|
extern unsigned int cpu_last_asid;
|
|
|
|
void __init_new_context(struct task_struct *tsk, struct mm_struct *mm);
|
|
void __new_context(struct mm_struct *mm);
|
|
|
|
#ifdef CONFIG_PID_IN_CONTEXTIDR
|
|
static inline void contextidr_thread_switch(struct task_struct *next)
|
|
{
|
|
asm(
|
|
" msr contextidr_el1, %0\n"
|
|
" isb"
|
|
:
|
|
: "r" (task_pid_nr(next)));
|
|
}
|
|
#else
|
|
static inline void contextidr_thread_switch(struct task_struct *next)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Set TTBR0 to empty_zero_page. No translations will be possible via TTBR0.
|
|
*/
|
|
static inline void cpu_set_reserved_ttbr0(void)
|
|
{
|
|
unsigned long ttbr = page_to_phys(empty_zero_page);
|
|
|
|
asm(
|
|
" msr ttbr0_el1, %0 // set TTBR0\n"
|
|
" isb"
|
|
:
|
|
: "r" (ttbr));
|
|
}
|
|
|
|
static inline void switch_new_context(struct mm_struct *mm)
|
|
{
|
|
unsigned long flags;
|
|
|
|
__new_context(mm);
|
|
|
|
local_irq_save(flags);
|
|
cpu_switch_mm(mm->pgd, mm);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static inline void check_and_switch_context(struct mm_struct *mm,
|
|
struct task_struct *tsk)
|
|
{
|
|
/*
|
|
* Required during context switch to avoid speculative page table
|
|
* walking with the wrong TTBR.
|
|
*/
|
|
cpu_set_reserved_ttbr0();
|
|
|
|
if (!((mm->context.id ^ cpu_last_asid) >> MAX_ASID_BITS))
|
|
/*
|
|
* The ASID is from the current generation, just switch to the
|
|
* new pgd. This condition is only true for calls from
|
|
* context_switch() and interrupts are already disabled.
|
|
*/
|
|
cpu_switch_mm(mm->pgd, mm);
|
|
else if (irqs_disabled())
|
|
/*
|
|
* Defer the new ASID allocation until after the context
|
|
* switch critical region since __new_context() cannot be
|
|
* called with interrupts disabled.
|
|
*/
|
|
set_ti_thread_flag(task_thread_info(tsk), TIF_SWITCH_MM);
|
|
else
|
|
/*
|
|
* That is a direct call to switch_mm() or activate_mm() with
|
|
* interrupts enabled and a new context.
|
|
*/
|
|
switch_new_context(mm);
|
|
}
|
|
|
|
#define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0)
|
|
#define destroy_context(mm) do { } while(0)
|
|
|
|
#define finish_arch_post_lock_switch \
|
|
finish_arch_post_lock_switch
|
|
static inline void finish_arch_post_lock_switch(void)
|
|
{
|
|
if (test_and_clear_thread_flag(TIF_SWITCH_MM)) {
|
|
struct mm_struct *mm = current->mm;
|
|
unsigned long flags;
|
|
|
|
__new_context(mm);
|
|
|
|
local_irq_save(flags);
|
|
cpu_switch_mm(mm->pgd, mm);
|
|
local_irq_restore(flags);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This is called when "tsk" is about to enter lazy TLB mode.
|
|
*
|
|
* mm: describes the currently active mm context
|
|
* tsk: task which is entering lazy tlb
|
|
* cpu: cpu number which is entering lazy tlb
|
|
*
|
|
* tsk->mm will be NULL
|
|
*/
|
|
static inline void
|
|
enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
|
|
{
|
|
}
|
|
|
|
/*
|
|
* This is the actual mm switch as far as the scheduler
|
|
* is concerned. No registers are touched. We avoid
|
|
* calling the CPU specific function when the mm hasn't
|
|
* actually changed.
|
|
*/
|
|
static inline void
|
|
switch_mm(struct mm_struct *prev, struct mm_struct *next,
|
|
struct task_struct *tsk)
|
|
{
|
|
unsigned int cpu = smp_processor_id();
|
|
|
|
if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next)
|
|
check_and_switch_context(next, tsk);
|
|
}
|
|
|
|
#define deactivate_mm(tsk,mm) do { } while (0)
|
|
#define activate_mm(prev,next) switch_mm(prev, next, NULL)
|
|
|
|
#endif
|