2 * Based on arch/arm/kernel/process.c
4 * Original Copyright (C) 1995 Linus Torvalds
5 * Copyright (C) 1996-2000 Russell King - Converted to ARM.
6 * Copyright (C) 2012 ARM Ltd.
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include <linux/compat.h>
24 #include <linux/efi.h>
25 #include <linux/export.h>
26 #include <linux/sched.h>
27 #include <linux/kernel.h>
29 #include <linux/stddef.h>
30 #include <linux/unistd.h>
31 #include <linux/user.h>
32 #include <linux/delay.h>
33 #include <linux/reboot.h>
34 #include <linux/interrupt.h>
35 #include <linux/kallsyms.h>
36 #include <linux/init.h>
37 #include <linux/cpu.h>
38 #include <linux/elfcore.h>
40 #include <linux/tick.h>
41 #include <linux/utsname.h>
42 #include <linux/uaccess.h>
43 #include <linux/random.h>
44 #include <linux/hw_breakpoint.h>
45 #include <linux/personality.h>
46 #include <linux/notifier.h>
47 #include <trace/events/power.h>
49 #include <asm/compat.h>
50 #include <asm/cacheflush.h>
51 #include <asm/fpsimd.h>
52 #include <asm/mmu_context.h>
53 #include <asm/processor.h>
54 #include <asm/stacktrace.h>
56 #ifdef CONFIG_CC_STACKPROTECTOR
57 #include <linux/stackprotector.h>
58 unsigned long __stack_chk_guard __read_mostly;
59 EXPORT_SYMBOL(__stack_chk_guard);
63 * Function pointers to optional machine specific functions
65 void (*pm_power_off)(void);
66 EXPORT_SYMBOL_GPL(pm_power_off);
68 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
71 * This is our default idle handler.
73 void arch_cpu_idle(void)
76 * This should do all the clock switching and wait for interrupt
79 trace_cpu_idle_rcuidle(1, smp_processor_id());
82 trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
85 #ifdef CONFIG_HOTPLUG_CPU
86 void arch_cpu_idle_dead(void)
93 * Called by kexec, immediately prior to machine_kexec().
95 * This must completely disable all secondary CPUs; simply causing those CPUs
96 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
97 * kexec'd kernel to use any and all RAM as it sees fit, without having to
98 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
99 * functionality embodied in disable_nonboot_cpus() to achieve this.
101 void machine_shutdown(void)
103 disable_nonboot_cpus();
107 * Halting simply requires that the secondary CPUs stop performing any
108 * activity (executing tasks, handling interrupts). smp_send_stop()
111 void machine_halt(void)
119 * Power-off simply requires that the secondary CPUs stop performing any
120 * activity (executing tasks, handling interrupts). smp_send_stop()
121 * achieves this. When the system power is turned off, it will take all CPUs
124 void machine_power_off(void)
133 * Restart requires that the secondary CPUs stop performing any activity
134 * while the primary CPU resets the system. Systems with multiple CPUs must
135 * provide a HW restart implementation, to ensure that all CPUs reset at once.
136 * This is required so that any code running after reset on the primary CPU
137 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
138 * executing pre-reset code, and using RAM that the primary CPU's code wishes
139 * to use. Implementing such co-ordination would be essentially impossible.
141 void machine_restart(char *cmd)
143 /* Disable interrupts first */
148 * UpdateCapsule() depends on the system being reset via
151 if (efi_enabled(EFI_RUNTIME_SERVICES))
152 efi_reboot(reboot_mode, NULL);
154 /* Now call the architecture specific reboot code. */
156 arm_pm_restart(reboot_mode, cmd);
158 do_kernel_restart(cmd);
161 * Whoops - the architecture was unable to reboot.
163 printk("Reboot failed -- System halted\n");
167 void __show_regs(struct pt_regs *regs)
172 if (compat_user_mode(regs)) {
173 lr = regs->compat_lr;
174 sp = regs->compat_sp;
182 show_regs_print_info(KERN_DEFAULT);
183 print_symbol("PC is at %s\n", instruction_pointer(regs));
184 print_symbol("LR is at %s\n", lr);
185 printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
186 regs->pc, lr, regs->pstate);
187 printk("sp : %016llx\n", sp);
188 for (i = top_reg; i >= 0; i--) {
189 printk("x%-2d: %016llx ", i, regs->regs[i]);
196 void show_regs(struct pt_regs * regs)
203 * Free current thread data structures etc..
205 void exit_thread(void)
209 static void tls_thread_flush(void)
211 asm ("msr tpidr_el0, xzr");
213 if (is_compat_task()) {
214 current->thread.tp_value = 0;
217 * We need to ensure ordering between the shadow state and the
218 * hardware state, so that we don't corrupt the hardware state
219 * with a stale shadow state during context switch.
222 asm ("msr tpidrro_el0, xzr");
226 void flush_thread(void)
228 fpsimd_flush_thread();
230 flush_ptrace_hw_breakpoint(current);
233 void release_thread(struct task_struct *dead_task)
237 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
240 fpsimd_preserve_current_state();
245 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
247 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
248 unsigned long stk_sz, struct task_struct *p)
250 struct pt_regs *childregs = task_pt_regs(p);
252 memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
254 if (likely(!(p->flags & PF_KTHREAD))) {
255 *childregs = *current_pt_regs();
256 childregs->regs[0] = 0;
259 * Read the current TLS pointer from tpidr_el0 as it may be
260 * out-of-sync with the saved value.
262 asm("mrs %0, tpidr_el0" : "=r" (*task_user_tls(p)));
265 if (is_compat_thread(task_thread_info(p)))
266 childregs->compat_sp = stack_start;
267 /* 16-byte aligned stack mandatory on AArch64 */
268 else if (stack_start & 15)
271 childregs->sp = stack_start;
275 * If a TLS pointer was passed to clone (4th argument), use it
276 * for the new thread.
278 if (clone_flags & CLONE_SETTLS)
279 p->thread.tp_value = childregs->regs[3];
281 memset(childregs, 0, sizeof(struct pt_regs));
282 childregs->pstate = PSR_MODE_EL1h;
283 p->thread.cpu_context.x19 = stack_start;
284 p->thread.cpu_context.x20 = stk_sz;
286 p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
287 p->thread.cpu_context.sp = (unsigned long)childregs;
289 ptrace_hw_copy_thread(p);
294 static void tls_thread_switch(struct task_struct *next)
296 unsigned long tpidr, tpidrro;
298 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
299 *task_user_tls(current) = tpidr;
301 tpidr = *task_user_tls(next);
302 tpidrro = is_compat_thread(task_thread_info(next)) ?
303 next->thread.tp_value : 0;
306 " msr tpidr_el0, %0\n"
307 " msr tpidrro_el0, %1"
308 : : "r" (tpidr), "r" (tpidrro));
314 struct task_struct *__switch_to(struct task_struct *prev,
315 struct task_struct *next)
317 struct task_struct *last;
319 fpsimd_thread_switch(next);
320 tls_thread_switch(next);
321 hw_breakpoint_thread_switch(next);
322 contextidr_thread_switch(next);
325 * Complete any pending TLB or cache maintenance on this CPU in case
326 * the thread migrates to a different CPU.
330 /* the actual thread switch */
331 last = cpu_switch_to(prev, next);
336 unsigned long get_wchan(struct task_struct *p)
338 struct stackframe frame;
339 unsigned long stack_page;
341 if (!p || p == current || p->state == TASK_RUNNING)
344 frame.fp = thread_saved_fp(p);
345 frame.sp = thread_saved_sp(p);
346 frame.pc = thread_saved_pc(p);
347 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
348 frame.graph = p->curr_ret_stack;
350 stack_page = (unsigned long)task_stack_page(p);
352 if (frame.sp < stack_page ||
353 frame.sp >= stack_page + THREAD_SIZE ||
354 unwind_frame(p, &frame))
356 if (!in_sched_functions(frame.pc))
358 } while (count ++ < 16);
362 unsigned long arch_align_stack(unsigned long sp)
364 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
365 sp -= get_random_int() & ~PAGE_MASK;
369 static unsigned long randomize_base(unsigned long base)
371 unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
372 return randomize_range(base, range_end, 0) ? : base;
375 unsigned long arch_randomize_brk(struct mm_struct *mm)
377 return randomize_base(mm->brk);