/* * 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 . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_THREAD_INFO_IN_TASK #include #endif #include #include #include #include #include #include #ifdef CONFIG_CC_STACKPROTECTOR #include unsigned long __stack_chk_guard __read_mostly; EXPORT_SYMBOL(__stack_chk_guard); #endif /* * Function pointers to optional machine specific functions */ void (*pm_power_off)(void); EXPORT_SYMBOL_GPL(pm_power_off); void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); /* * This is our default idle handler. */ void arch_cpu_idle(void) { /* * This should do all the clock switching and wait for interrupt * tricks */ trace_cpu_idle_rcuidle(1, smp_processor_id()); cpu_do_idle(); local_irq_enable(); trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); } #ifdef CONFIG_HOTPLUG_CPU void arch_cpu_idle_dead(void) { cpu_die(); } #endif /* * 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) { 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) { local_irq_disable(); smp_send_stop(); 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) { local_irq_disable(); 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 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) { /* Disable interrupts first */ local_irq_disable(); smp_send_stop(); /* * UpdateCapsule() depends on the system being reset via * ResetSystem(). */ if (efi_enabled(EFI_RUNTIME_SERVICES)) efi_reboot(reboot_mode, NULL); /* Now call the architecture specific reboot code. */ if (arm_pm_restart) arm_pm_restart(reboot_mode, cmd); else do_kernel_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, top_reg; u64 lr, sp; if (compat_user_mode(regs)) { lr = regs->compat_lr; sp = regs->compat_sp; top_reg = 12; } else { lr = regs->regs[30]; sp = regs->sp; top_reg = 29; } show_regs_print_info(KERN_DEFAULT); print_symbol("PC is at %s\n", instruction_pointer(regs)); print_symbol("LR is at %s\n", lr); printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", regs->pc, lr, regs->pstate); printk("sp : %016llx\n", sp); for (i = top_reg; 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"); __show_regs(regs); } /* * Free current thread data structures etc.. */ void exit_thread(void) { } static void tls_thread_flush(void) { asm ("msr tpidr_el0, xzr"); if (is_compat_task()) { current->thread.tp_value = 0; /* * We need to ensure ordering between the shadow state and the * hardware state, so that we don't corrupt the hardware state * with a stale shadow state during context switch. */ barrier(); asm ("msr tpidrro_el0, xzr"); } } void flush_thread(void) { fpsimd_flush_thread(); tls_thread_flush(); 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) { if (current->mm) fpsimd_preserve_current_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 *childregs = task_pt_regs(p); memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context)); /* * In case p was allocated the same task_struct pointer as some * other recently-exited task, make sure p is disassociated from * any cpu that may have run that now-exited task recently. * Otherwise we could erroneously skip reloading the FPSIMD * registers for p. */ fpsimd_flush_task_state(p); if (likely(!(p->flags & PF_KTHREAD))) { *childregs = *current_pt_regs(); childregs->regs[0] = 0; /* * 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" (*task_user_tls(p))); if (stack_start) { if (is_compat_thread(task_thread_info(p))) childregs->compat_sp = stack_start; /* 16-byte aligned stack mandatory on AArch64 */ else if (stack_start & 15) return -EINVAL; else childregs->sp = stack_start; } /* * If a TLS pointer was passed to clone (4th argument), use it * for the new thread. */ if (clone_flags & CLONE_SETTLS) p->thread.tp_value = childregs->regs[3]; } else { memset(childregs, 0, sizeof(struct pt_regs)); childregs->pstate = PSR_MODE_EL1h; p->thread.cpu_context.x19 = stack_start; p->thread.cpu_context.x20 = stk_sz; } p->thread.cpu_context.pc = (unsigned long)ret_from_fork; p->thread.cpu_context.sp = (unsigned long)childregs; ptrace_hw_copy_thread(p); return 0; } static void tls_thread_switch(struct task_struct *next) { unsigned long tpidr, tpidrro; asm("mrs %0, tpidr_el0" : "=r" (tpidr)); *task_user_tls(current) = tpidr; tpidr = *task_user_tls(next); tpidrro = is_compat_thread(task_thread_info(next)) ? next->thread.tp_value : 0; asm( " msr tpidr_el0, %0\n" " msr tpidrro_el0, %1" : : "r" (tpidr), "r" (tpidrro)); } #ifdef CONFIG_THREAD_INFO_IN_TASK /* * We store our current task in sp_el0, which is clobbered by userspace. Keep a * shadow copy so that we can restore this upon entry from userspace. * * This is *only* for exception entry from EL0, and is not valid until we * __switch_to() a user task. */ DEFINE_PER_CPU(struct task_struct *, __entry_task); static void entry_task_switch(struct task_struct *next) { __this_cpu_write(__entry_task, next); } #endif /* * 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); contextidr_thread_switch(next); #ifdef CONFIG_THREAD_INFO_IN_TASK entry_task_switch(next); #endif /* * Complete any pending TLB or cache maintenance on this CPU in case * the thread migrates to a different CPU. */ dsb(ish); /* the actual thread switch */ last = cpu_switch_to(prev, next); return last; } unsigned long get_wchan(struct task_struct *p) { struct stackframe frame; unsigned long stack_page; 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); stack_page = (unsigned long)task_stack_page(p); do { if (frame.sp < stack_page || frame.sp >= stack_page + THREAD_SIZE || unwind_frame(&frame)) 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); }