diff options
Diffstat (limited to 'arch/arm/kernel/process.c')
-rw-r--r-- | arch/arm/kernel/process.c | 163 |
1 files changed, 71 insertions, 92 deletions
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 047d3e40e470..6e8931ccf13e 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -57,38 +57,6 @@ static const char *isa_modes[] = { "ARM" , "Thumb" , "Jazelle", "ThumbEE" }; -static volatile int hlt_counter; - -void disable_hlt(void) -{ - hlt_counter++; -} - -EXPORT_SYMBOL(disable_hlt); - -void enable_hlt(void) -{ - hlt_counter--; - BUG_ON(hlt_counter < 0); -} - -EXPORT_SYMBOL(enable_hlt); - -static int __init nohlt_setup(char *__unused) -{ - hlt_counter = 1; - return 1; -} - -static int __init hlt_setup(char *__unused) -{ - hlt_counter = 0; - return 1; -} - -__setup("nohlt", nohlt_setup); -__setup("hlt", hlt_setup); - extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); typedef void (*phys_reset_t)(unsigned long); @@ -172,54 +140,38 @@ static void default_idle(void) local_irq_enable(); } -/* - * The idle thread. - * We always respect 'hlt_counter' to prevent low power idle. - */ -void cpu_idle(void) +void arch_cpu_idle_prepare(void) { local_fiq_enable(); +} - /* endless idle loop with no priority at all */ - while (1) { - tick_nohz_idle_enter(); - rcu_idle_enter(); - ledtrig_cpu(CPU_LED_IDLE_START); - while (!need_resched()) { -#ifdef CONFIG_HOTPLUG_CPU - if (cpu_is_offline(smp_processor_id())) - cpu_die(); +void arch_cpu_idle_enter(void) +{ + ledtrig_cpu(CPU_LED_IDLE_START); +#ifdef CONFIG_PL310_ERRATA_769419 + wmb(); #endif +} - /* - * We need to disable interrupts here - * to ensure we don't miss a wakeup call. - */ - local_irq_disable(); -#ifdef CONFIG_PL310_ERRATA_769419 - wmb(); +void arch_cpu_idle_exit(void) +{ + ledtrig_cpu(CPU_LED_IDLE_END); +} + +#ifdef CONFIG_HOTPLUG_CPU +void arch_cpu_idle_dead(void) +{ + cpu_die(); +} #endif - if (hlt_counter) { - local_irq_enable(); - cpu_relax(); - } else if (!need_resched()) { - stop_critical_timings(); - if (cpuidle_idle_call()) - default_idle(); - start_critical_timings(); - /* - * default_idle functions must always - * return with IRQs enabled. - */ - WARN_ON(irqs_disabled()); - } else - local_irq_enable(); - } - ledtrig_cpu(CPU_LED_IDLE_END); - rcu_idle_exit(); - tick_nohz_idle_exit(); - schedule_preempt_disabled(); - } + +/* + * Called from the core idle loop. + */ +void arch_cpu_idle(void) +{ + if (cpuidle_idle_call()) + default_idle(); } static char reboot_mode = 'h'; @@ -232,30 +184,61 @@ int __init reboot_setup(char *str) __setup("reboot=", reboot_setup); +/* + * Called by kexec, immediately prior to machine_kexec(). + * + * This must completely disable all secondary CPUs; simply causing those CPUs + * to execute e.g. a RAM-based pin loop is not sufficient. This allows the + * kexec'd kernel to use any and all RAM as it sees fit, without having to + * avoid any code or data used by any SW CPU pin loop. The CPU hotplug + * functionality embodied in disable_nonboot_cpus() to achieve this. + */ void machine_shutdown(void) { -#ifdef CONFIG_SMP - smp_send_stop(); -#endif + disable_nonboot_cpus(); } +/* + * Halting simply requires that the secondary CPUs stop performing any + * activity (executing tasks, handling interrupts). smp_send_stop() + * achieves this. + */ void machine_halt(void) { - machine_shutdown(); + smp_send_stop(); + local_irq_disable(); while (1); } +/* + * Power-off simply requires that the secondary CPUs stop performing any + * activity (executing tasks, handling interrupts). smp_send_stop() + * achieves this. When the system power is turned off, it will take all CPUs + * with it. + */ void machine_power_off(void) { - machine_shutdown(); + smp_send_stop(); + if (pm_power_off) pm_power_off(); } +/* + * Restart requires that the secondary CPUs stop performing any activity + * while the primary CPU resets the system. Systems with a single CPU can + * use soft_restart() as their machine descriptor's .restart hook, since that + * will cause the only available CPU to reset. Systems with multiple CPUs must + * provide a HW restart implementation, to ensure that all CPUs reset at once. + * This is required so that any code running after reset on the primary CPU + * doesn't have to co-ordinate with other CPUs to ensure they aren't still + * executing pre-reset code, and using RAM that the primary CPU's code wishes + * to use. Implementing such co-ordination would be essentially impossible. + */ void machine_restart(char *cmd) { - machine_shutdown(); + smp_send_stop(); arm_pm_restart(reboot_mode, cmd); @@ -273,11 +256,8 @@ void __show_regs(struct pt_regs *regs) unsigned long flags; char buf[64]; - printk("CPU: %d %s (%s %.*s)\n", - raw_smp_processor_id(), print_tainted(), - init_utsname()->release, - (int)strcspn(init_utsname()->version, " "), - init_utsname()->version); + show_regs_print_info(KERN_DEFAULT); + print_symbol("PC is at %s\n", instruction_pointer(regs)); print_symbol("LR is at %s\n", regs->ARM_lr); printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n" @@ -332,7 +312,6 @@ void __show_regs(struct pt_regs *regs) void show_regs(struct pt_regs * regs) { printk("\n"); - printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm); __show_regs(regs); dump_stack(); } @@ -459,15 +438,15 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) * atomic helpers and the signal restart code. Insert it into the * gate_vma so that it is visible through ptrace and /proc/<pid>/mem. */ -static struct vm_area_struct gate_vma; +static struct vm_area_struct gate_vma = { + .vm_start = 0xffff0000, + .vm_end = 0xffff0000 + PAGE_SIZE, + .vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC, +}; static int __init gate_vma_init(void) { - gate_vma.vm_start = 0xffff0000; - gate_vma.vm_end = 0xffff0000 + PAGE_SIZE; - gate_vma.vm_page_prot = PAGE_READONLY_EXEC; - gate_vma.vm_flags = VM_READ | VM_EXEC | - VM_MAYREAD | VM_MAYEXEC; + gate_vma.vm_page_prot = PAGE_READONLY_EXEC; return 0; } arch_initcall(gate_vma_init); |