diff options
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/include/asm/mmu_context.h | 152 | ||||
| -rw-r--r-- | arch/arm64/include/asm/thread_info.h | 127 | ||||
| -rw-r--r-- | arch/arm64/kernel/process.c | 408 | ||||
| -rw-r--r-- | arch/arm64/mm/context.c | 159 |
4 files changed, 846 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h new file mode 100644 index 000000000000..f68465dee026 --- /dev/null +++ b/arch/arm64/include/asm/mmu_context.h @@ -0,0 +1,152 @@ +/* + * 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); + +/* + * 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(); + +#ifdef CONFIG_SMP + /* check for possible thread migration */ + if (!cpumask_empty(mm_cpumask(next)) && + !cpumask_test_cpu(cpu, mm_cpumask(next))) + __flush_icache_all(); +#endif + 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 diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h new file mode 100644 index 000000000000..3659e460071d --- /dev/null +++ b/arch/arm64/include/asm/thread_info.h @@ -0,0 +1,127 @@ +/* + * Based on arch/arm/include/asm/thread_info.h + * + * Copyright (C) 2002 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_THREAD_INFO_H +#define __ASM_THREAD_INFO_H + +#ifdef __KERNEL__ + +#include <linux/compiler.h> + +#ifndef CONFIG_ARM64_64K_PAGES +#define THREAD_SIZE_ORDER 1 +#endif + +#define THREAD_SIZE 8192 +#define THREAD_START_SP (THREAD_SIZE - 16) + +#ifndef __ASSEMBLY__ + +struct task_struct; +struct exec_domain; + +#include <asm/types.h> + +typedef unsigned long mm_segment_t; + +/* + * low level task data that entry.S needs immediate access to. + * __switch_to() assumes cpu_context follows immediately after cpu_domain. + */ +struct thread_info { + unsigned long flags; /* low level flags */ + mm_segment_t addr_limit; /* address limit */ + struct task_struct *task; /* main task structure */ + struct exec_domain *exec_domain; /* execution domain */ + struct restart_block restart_block; + int preempt_count; /* 0 => preemptable, <0 => bug */ + int cpu; /* cpu */ +}; + +#define INIT_THREAD_INFO(tsk) \ +{ \ + .task = &tsk, \ + .exec_domain = &default_exec_domain, \ + .flags = 0, \ + .preempt_count = INIT_PREEMPT_COUNT, \ + .addr_limit = KERNEL_DS, \ + .restart_block = { \ + .fn = do_no_restart_syscall, \ + }, \ +} + +#define init_thread_info (init_thread_union.thread_info) +#define init_stack (init_thread_union.stack) + +/* + * how to get the thread information struct from C + */ +static inline struct thread_info *current_thread_info(void) __attribute_const__; + +static inline struct thread_info *current_thread_info(void) +{ + register unsigned long sp asm ("sp"); + return (struct thread_info *)(sp & ~(THREAD_SIZE - 1)); +} + +#define thread_saved_pc(tsk) \ + ((unsigned long)(tsk->thread.cpu_context.pc)) +#define thread_saved_sp(tsk) \ + ((unsigned long)(tsk->thread.cpu_context.sp)) +#define thread_saved_fp(tsk) \ + ((unsigned long)(tsk->thread.cpu_context.fp)) + +#endif + +/* + * We use bit 30 of the preempt_count to indicate that kernel + * preemption is occurring. See <asm/hardirq.h>. + */ +#define PREEMPT_ACTIVE 0x40000000 + +/* + * thread information flags: + * TIF_SYSCALL_TRACE - syscall trace active + * TIF_SIGPENDING - signal pending + * TIF_NEED_RESCHED - rescheduling necessary + * TIF_NOTIFY_RESUME - callback before returning to user + * TIF_USEDFPU - FPU was used by this task this quantum (SMP) + * TIF_POLLING_NRFLAG - true if poll_idle() is polling TIF_NEED_RESCHED + */ +#define TIF_SIGPENDING 0 +#define TIF_NEED_RESCHED 1 +#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ +#define TIF_SYSCALL_TRACE 8 +#define TIF_POLLING_NRFLAG 16 +#define TIF_MEMDIE 18 /* is terminating due to OOM killer */ +#define TIF_FREEZE 19 +#define TIF_RESTORE_SIGMASK 20 +#define TIF_SINGLESTEP 21 +#define TIF_32BIT 22 /* 32bit process */ +#define TIF_SWITCH_MM 23 /* deferred switch_mm */ + +#define _TIF_SIGPENDING (1 << TIF_SIGPENDING) +#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) +#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) +#define _TIF_32BIT (1 << TIF_32BIT) + +#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \ + _TIF_NOTIFY_RESUME) + +#endif /* __KERNEL__ */ +#endif /* __ASM_THREAD_INFO_H */ diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c new file mode 100644 index 000000000000..f22965ea1cfc --- /dev/null +++ b/arch/arm64/kernel/process.c @@ -0,0 +1,408 @@ +/* + * Based on arch/arm/kernel/process.c + * + * Original Copyright (C) 1995 Linus Torvalds + * Copyright (C) 1996-2000 Russell King - Converted to ARM. + * 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/>. + */ + +#include <stdarg.h> + +#include <linux/export.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/stddef.h> +#include <linux/unistd.h> +#include <linux/user.h> +#include <linux/delay.h> +#include <linux/reboot.h> +#include <linux/interrupt.h> +#include <linux/kallsyms.h> +#include <linux/init.h> +#include <linux/cpu.h> +#include <linux/elfcore.h> +#include <linux/pm.h> +#include <linux/tick.h> +#include <linux/utsname.h> +#include <linux/uaccess.h> +#include <linux/random.h> +#include <linux/hw_breakpoint.h> +#include <linux/personality.h> +#include <linux/notifier.h> + +#include <asm/compat.h> +#include <asm/cacheflush.h> +#include <asm/processor.h> +#include <asm/stacktrace.h> +#include <asm/fpsimd.h> + +static void setup_restart(void) +{ + /* + * Tell the mm system that we are going to reboot - + * we may need it to insert some 1:1 mappings so that + * soft boot works. + */ + setup_mm_for_reboot(); + + /* Clean and invalidate caches */ + flush_cache_all(); + + /* Turn D-cache off */ + cpu_cache_off(); + + /* Push out any further dirty data, and ensure cache is empty */ + flush_cache_all(); +} + +void soft_restart(unsigned long addr) +{ + setup_restart(); + cpu_reset(addr); +} + +/* + * Function pointers to optional machine specific functions + */ +void (*pm_power_off)(void); +EXPORT_SYMBOL_GPL(pm_power_off); + +void (*pm_restart)(const char *cmd); +EXPORT_SYMBOL_GPL(pm_restart); + + +/* + * This is our default idle handler. + */ +static void default_idle(void) +{ + /* + * This should do all the clock switching and wait for interrupt + * tricks + */ + cpu_do_idle(); + local_irq_enable(); +} + +void (*pm_idle)(void) = default_idle; +EXPORT_SYMBOL_GPL(pm_idle); + +/* + * The idle thread, has rather strange semantics for calling pm_idle, + * but this is what x86 does and we need to do the same, so that + * things like cpuidle get called in the same way. The only difference + * is that we always respect 'hlt_counter' to prevent low power idle. + */ +void cpu_idle(void) +{ + local_fiq_enable(); + + /* endless idle loop with no priority at all */ + while (1) { + tick_nohz_idle_enter(); + rcu_idle_enter(); + while (!need_resched()) { + /* + * We need to disable interrupts here to ensure + * we don't miss a wakeup call. + */ + local_irq_disable(); + if (!need_resched()) { + stop_critical_timings(); + pm_idle(); + start_critical_timings(); + /* + * pm_idle functions should always return + * with IRQs enabled. + */ + WARN_ON(irqs_disabled()); + } else { + local_irq_enable(); + } + } + rcu_idle_exit(); + tick_nohz_idle_exit(); + schedule_preempt_disabled(); + } +} + +void machine_shutdown(void) +{ +#ifdef CONFIG_SMP + smp_send_stop(); +#endif +} + +void machine_halt(void) +{ + machine_shutdown(); + while (1); +} + +void machine_power_off(void) +{ + machine_shutdown(); + if (pm_power_off) + pm_power_off(); +} + +void machine_restart(char *cmd) +{ + machine_shutdown(); + + /* Disable interrupts first */ + local_irq_disable(); + local_fiq_disable(); + + /* Now call the architecture specific reboot code. */ + if (pm_restart) + pm_restart(cmd); + + /* + * Whoops - the architecture was unable to reboot. + */ + printk("Reboot failed -- System halted\n"); + while (1); +} + +void __show_regs(struct pt_regs *regs) +{ + int i; + + printk("CPU: %d %s (%s %.*s)\n", + raw_smp_processor_id(), print_tainted(), + init_utsname()->release, + (int)strcspn(init_utsname()->version, " "), + init_utsname()->version); + print_symbol("PC is at %s\n", instruction_pointer(regs)); + print_symbol("LR is at %s\n", regs->regs[30]); + printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", + regs->pc, regs->regs[30], regs->pstate); + printk("sp : %016llx\n", regs->sp); + for (i = 29; i >= 0; i--) { + printk("x%-2d: %016llx ", i, regs->regs[i]); + if (i % 2 == 0) + printk("\n"); + } + printk("\n"); +} + +void show_regs(struct pt_regs * regs) +{ + printk("\n"); + printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); + __show_regs(regs); +} + +/* + * Free current thread data structures etc.. + */ +void exit_thread(void) +{ +} + +void flush_thread(void) +{ + fpsimd_flush_thread(); + flush_ptrace_hw_breakpoint(current); +} + +void release_thread(struct task_struct *dead_task) +{ +} + +int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) +{ + fpsimd_save_state(¤t->thread.fpsimd_state); + *dst = *src; + return 0; +} + +asmlinkage void ret_from_fork(void) asm("ret_from_fork"); + +int copy_thread(unsigned long clone_flags, unsigned long stack_start, + unsigned long stk_sz, struct task_struct *p, + struct pt_regs *regs) +{ + struct pt_regs *childregs = task_pt_regs(p); + unsigned long tls = p->thread.tp_value; + + *childregs = *regs; + childregs->regs[0] = 0; + + if (is_compat_thread(task_thread_info(p))) + childregs->compat_sp = stack_start; + else { + /* + * Read the current TLS pointer from tpidr_el0 as it may be + * out-of-sync with the saved value. + */ + asm("mrs %0, tpidr_el0" : "=r" (tls)); + childregs->sp = stack_start; + } + + memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context)); + p->thread.cpu_context.sp = (unsigned long)childregs; + p->thread.cpu_context.pc = (unsigned long)ret_from_fork; + + /* If a TLS pointer was passed to clone, use that for the new thread. */ + if (clone_flags & CLONE_SETTLS) + tls = regs->regs[3]; + p->thread.tp_value = tls; + + ptrace_hw_copy_thread(p); + + return 0; +} + +static void tls_thread_switch(struct task_struct *next) +{ + unsigned long tpidr, tpidrro; + + if (!is_compat_task()) { + asm("mrs %0, tpidr_el0" : "=r" (tpidr)); + current->thread.tp_value = tpidr; + } + + if (is_compat_thread(task_thread_info(next))) { + tpidr = 0; + tpidrro = next->thread.tp_value; + } else { + tpidr = next->thread.tp_value; + tpidrro = 0; + } + + asm( + " msr tpidr_el0, %0\n" + " msr tpidrro_el0, %1" + : : "r" (tpidr), "r" (tpidrro)); +} + +/* + * Thread switching. + */ +struct task_struct *__switch_to(struct task_struct *prev, + struct task_struct *next) +{ + struct task_struct *last; + + fpsimd_thread_switch(next); + tls_thread_switch(next); + hw_breakpoint_thread_switch(next); + + /* the actual thread switch */ + last = cpu_switch_to(prev, next); + + return last; +} + +/* + * Fill in the task's elfregs structure for a core dump. + */ +int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs) +{ + elf_core_copy_regs(elfregs, task_pt_regs(t)); + return 1; +} + +/* + * fill in the fpe structure for a core dump... + */ +int dump_fpu (struct pt_regs *regs, struct user_fp *fp) +{ + return 0; +} +EXPORT_SYMBOL(dump_fpu); + +/* + * Shuffle the argument into the correct register before calling the + * thread function. x1 is the thread argument, x2 is the pointer to + * the thread function, and x3 points to the exit function. + */ +extern void kernel_thread_helper(void); +asm( ".section .text\n" +" .align\n" +" .type kernel_thread_helper, #function\n" +"kernel_thread_helper:\n" +" mov x0, x1\n" +" mov x30, x3\n" +" br x2\n" +" .size kernel_thread_helper, . - kernel_thread_helper\n" +" .previous"); + +#define kernel_thread_exit do_exit + +/* + * Create a kernel thread. + */ +pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags) +{ + struct pt_regs regs; + + memset(®s, 0, sizeof(regs)); + + regs.regs[1] = (unsigned long)arg; + regs.regs[2] = (unsigned long)fn; + regs.regs[3] = (unsigned long)kernel_thread_exit; + regs.pc = (unsigned long)kernel_thread_helper; + regs.pstate = PSR_MODE_EL1h; + + return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL); +} +EXPORT_SYMBOL(kernel_thread); + +unsigned long get_wchan(struct task_struct *p) +{ + struct stackframe frame; + int count = 0; + if (!p || p == current || p->state == TASK_RUNNING) + return 0; + + frame.fp = thread_saved_fp(p); + frame.sp = thread_saved_sp(p); + frame.pc = thread_saved_pc(p); + do { + int ret = unwind_frame(&frame); + if (ret < 0) + return 0; + if (!in_sched_functions(frame.pc)) + return frame.pc; + } while (count ++ < 16); + return 0; +} + +unsigned long arch_align_stack(unsigned long sp) +{ + if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + sp -= get_random_int() & ~PAGE_MASK; + return sp & ~0xf; +} + +static unsigned long randomize_base(unsigned long base) +{ + unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1; + return randomize_range(base, range_end, 0) ? : base; +} + +unsigned long arch_randomize_brk(struct mm_struct *mm) +{ + return randomize_base(mm->brk); +} + +unsigned long randomize_et_dyn(unsigned long base) +{ + return randomize_base(base); +} diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c new file mode 100644 index 000000000000..baa758d37021 --- /dev/null +++ b/arch/arm64/mm/context.c @@ -0,0 +1,159 @@ +/* + * Based on arch/arm/mm/context.c + * + * Copyright (C) 2002-2003 Deep Blue Solutions Ltd, all rights reserved. + * 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/>. + */ + +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/percpu.h> + +#include <asm/mmu_context.h> +#include <asm/tlbflush.h> +#include <asm/cachetype.h> + +#define asid_bits(reg) \ + (((read_cpuid(ID_AA64MMFR0_EL1) & 0xf0) >> 2) + 8) + +#define ASID_FIRST_VERSION (1 << MAX_ASID_BITS) + +static DEFINE_RAW_SPINLOCK(cpu_asid_lock); +unsigned int cpu_last_asid = ASID_FIRST_VERSION; + +/* + * We fork()ed a process, and we need a new context for the child to run in. + */ +void __init_new_context(struct task_struct *tsk, struct mm_struct *mm) +{ + mm->context.id = 0; + raw_spin_lock_init(&mm->context.id_lock); +} + +static void flush_context(void) +{ + /* set the reserved TTBR0 before flushing the TLB */ + cpu_set_reserved_ttbr0(); + flush_tlb_all(); + if (icache_is_aivivt()) + __flush_icache_all(); +} + +#ifdef CONFIG_SMP + +static void set_mm_context(struct mm_struct *mm, unsigned int asid) +{ + unsigned long flags; + + /* + * Locking needed for multi-threaded applications where the same + * mm->context.id could be set from different CPUs during the + * broadcast. This function is also called via IPI so the + * mm->context.id_lock has to be IRQ-safe. + */ + raw_spin_lock_irqsave(&mm->context.id_lock, flags); + if (likely((mm->context.id ^ cpu_last_asid) >> MAX_ASID_BITS)) { + /* + * Old version of ASID found. Set the new one and reset + * mm_cpumask(mm). + */ + mm->context.id = asid; + cpumask_clear(mm_cpumask(mm)); + } + raw_spin_unlock_irqrestore(&mm->context.id_lock, flags); + + /* + * Set the mm_cpumask(mm) bit for the current CPU. + */ + cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); +} + +/* + * Reset the ASID on the current CPU. This function call is broadcast from the + * CPU handling the ASID rollover and holding cpu_asid_lock. + */ +static void reset_context(void *info) +{ + unsigned int asid; + unsigned int cpu = smp_processor_id(); + struct mm_struct *mm = current->active_mm; + + smp_rmb(); + asid = cpu_last_asid + cpu; + + flush_context(); + set_mm_context(mm, asid); + + /* set the new ASID */ + cpu_switch_mm(mm->pgd, mm); +} + +#else + +static inline void set_mm_context(struct mm_struct *mm, unsigned int asid) +{ + mm->context.id = asid; + cpumask_copy(mm_cpumask(mm), cpumask_of(smp_processor_id())); +} + +#endif + +void __new_context(struct mm_struct *mm) +{ + unsigned int asid; + unsigned int bits = asid_bits(); + + raw_spin_lock(&cpu_asid_lock); +#ifdef CONFIG_SMP + /* + * Check the ASID again, in case the change was broadcast from another + * CPU before we acquired the lock. + */ + if (!unlikely((mm->context.id ^ cpu_last_asid) >> MAX_ASID_BITS)) { + cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); + raw_spin_unlock(&cpu_asid_lock); + return; + } +#endif + /* + * At this point, it is guaranteed that the current mm (with an old + * ASID) isn't active on any other CPU since the ASIDs are changed + * simultaneously via IPI. + */ + asid = ++cpu_last_asid; + + /* + * If we've used up all our ASIDs, we need to start a new version and + * flush the TLB. + */ + if (unlikely((asid & ((1 << bits) - 1)) == 0)) { + /* increment the ASID version */ + cpu_last_asid += (1 << MAX_ASID_BITS) - (1 << bits); + if (cpu_last_asid == 0) + cpu_last_asid = ASID_FIRST_VERSION; + asid = cpu_last_asid + smp_processor_id(); + flush_context(); +#ifdef CONFIG_SMP + smp_wmb(); + smp_call_function(reset_context, NULL, 1); +#endif + cpu_last_asid += NR_CPUS - 1; + } + + set_mm_context(mm, asid); + raw_spin_unlock(&cpu_asid_lock); +} |
