From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/arm64/include/asm/mmu_context.h | 213 +++++++++++++++++++++++++++++++++++ 1 file changed, 213 insertions(+) create mode 100644 arch/arm64/include/asm/mmu_context.h (limited to 'arch/arm64/include/asm/mmu_context.h') diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h new file mode 100644 index 000000000..8ec41e5f5 --- /dev/null +++ b/arch/arm64/include/asm/mmu_context.h @@ -0,0 +1,213 @@ +/* + * 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 . + */ +#ifndef __ASM_MMU_CONTEXT_H +#define __ASM_MMU_CONTEXT_H + +#include +#include + +#include +#include +#include +#include +#include + +#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)); +} + +/* + * TCR.T0SZ value to use when the ID map is active. Usually equals + * TCR_T0SZ(VA_BITS), unless system RAM is positioned very high in + * physical memory, in which case it will be smaller. + */ +extern u64 idmap_t0sz; + +static inline bool __cpu_uses_extended_idmap(void) +{ + return (!IS_ENABLED(CONFIG_ARM64_VA_BITS_48) && + unlikely(idmap_t0sz != TCR_T0SZ(VA_BITS))); +} + +static inline void __cpu_set_tcr_t0sz(u64 t0sz) +{ + unsigned long tcr; + + if (__cpu_uses_extended_idmap()) + asm volatile ( + " mrs %0, tcr_el1 ;" + " bfi %0, %1, %2, %3 ;" + " msr tcr_el1, %0 ;" + " isb" + : "=&r" (tcr) + : "r"(t0sz), "I"(TCR_T0SZ_OFFSET), "I"(TCR_TxSZ_WIDTH)); +} + +/* + * Set TCR.T0SZ to the value appropriate for activating the identity map. + */ +static inline void cpu_set_idmap_tcr_t0sz(void) +{ + __cpu_set_tcr_t0sz(idmap_t0sz); +} + +/* + * Set TCR.T0SZ to its default value (based on VA_BITS) + */ +static inline void cpu_set_default_tcr_t0sz(void) +{ + __cpu_set_tcr_t0sz(TCR_T0SZ(VA_BITS)); +} + +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(); + + /* + * init_mm.pgd does not contain any user mappings and it is always + * active for kernel addresses in TTBR1. Just set the reserved TTBR0. + */ + if (next == &init_mm) { + cpu_set_reserved_ttbr0(); + return; + } + + 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 -- cgit v1.2.3-54-g00ecf