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>
48 #include <asm/compat.h>
49 #include <asm/cacheflush.h>
50 #include <asm/fpsimd.h>
51 #include <asm/mmu_context.h>
52 #include <asm/processor.h>
53 #include <asm/stacktrace.h>
55 #ifdef CONFIG_CC_STACKPROTECTOR
56 #include <linux/stackprotector.h>
57 unsigned long __stack_chk_guard __read_mostly;
58 EXPORT_SYMBOL(__stack_chk_guard);
61 void soft_restart(unsigned long addr)
63 setup_mm_for_reboot();
64 cpu_soft_restart(virt_to_phys(cpu_reset), addr);
65 /* Should never get here */
70 * Function pointers to optional machine specific functions
72 void (*pm_power_off)(void);
73 EXPORT_SYMBOL_GPL(pm_power_off);
75 void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
78 * This is our default idle handler.
80 void arch_cpu_idle(void)
83 * This should do all the clock switching and wait for interrupt
90 #ifdef CONFIG_HOTPLUG_CPU
91 void arch_cpu_idle_dead(void)
98 * Called by kexec, immediately prior to machine_kexec().
100 * This must completely disable all secondary CPUs; simply causing those CPUs
101 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
102 * kexec'd kernel to use any and all RAM as it sees fit, without having to
103 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
104 * functionality embodied in disable_nonboot_cpus() to achieve this.
106 void machine_shutdown(void)
108 disable_nonboot_cpus();
112 * Halting simply requires that the secondary CPUs stop performing any
113 * activity (executing tasks, handling interrupts). smp_send_stop()
116 void machine_halt(void)
124 * Power-off simply requires that the secondary CPUs stop performing any
125 * activity (executing tasks, handling interrupts). smp_send_stop()
126 * achieves this. When the system power is turned off, it will take all CPUs
129 void machine_power_off(void)
138 * Restart requires that the secondary CPUs stop performing any activity
139 * while the primary CPU resets the system. Systems with a single CPU can
140 * use soft_restart() as their machine descriptor's .restart hook, since that
141 * will cause the only available CPU to reset. Systems with multiple CPUs must
142 * provide a HW restart implementation, to ensure that all CPUs reset at once.
143 * This is required so that any code running after reset on the primary CPU
144 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
145 * executing pre-reset code, and using RAM that the primary CPU's code wishes
146 * to use. Implementing such co-ordination would be essentially impossible.
148 void machine_restart(char *cmd)
150 /* Disable interrupts first */
155 * UpdateCapsule() depends on the system being reset via
158 if (efi_enabled(EFI_RUNTIME_SERVICES))
159 efi_reboot(reboot_mode, NULL);
161 /* Now call the architecture specific reboot code. */
163 arm_pm_restart(reboot_mode, cmd);
165 do_kernel_restart(cmd);
168 * Whoops - the architecture was unable to reboot.
170 printk("Reboot failed -- System halted\n");
174 void __show_regs(struct pt_regs *regs)
179 if (compat_user_mode(regs)) {
180 lr = regs->compat_lr;
181 sp = regs->compat_sp;
189 show_regs_print_info(KERN_DEFAULT);
190 print_symbol("PC is at %s\n", instruction_pointer(regs));
191 print_symbol("LR is at %s\n", lr);
192 printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
193 regs->pc, lr, regs->pstate);
194 printk("sp : %016llx\n", sp);
195 for (i = top_reg; i >= 0; i--) {
196 printk("x%-2d: %016llx ", i, regs->regs[i]);
203 void show_regs(struct pt_regs * regs)
210 * Free current thread data structures etc..
212 void exit_thread(void)
216 static void tls_thread_flush(void)
218 asm ("msr tpidr_el0, xzr");
220 if (is_compat_task()) {
221 current->thread.tp_value = 0;
224 * We need to ensure ordering between the shadow state and the
225 * hardware state, so that we don't corrupt the hardware state
226 * with a stale shadow state during context switch.
229 asm ("msr tpidrro_el0, xzr");
233 void flush_thread(void)
235 fpsimd_flush_thread();
237 flush_ptrace_hw_breakpoint(current);
240 void release_thread(struct task_struct *dead_task)
244 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
246 fpsimd_preserve_current_state();
251 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
253 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
254 unsigned long stk_sz, struct task_struct *p)
256 struct pt_regs *childregs = task_pt_regs(p);
257 unsigned long tls = p->thread.tp_value;
259 memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
261 if (likely(!(p->flags & PF_KTHREAD))) {
262 *childregs = *current_pt_regs();
263 childregs->regs[0] = 0;
264 if (is_compat_thread(task_thread_info(p))) {
266 childregs->compat_sp = stack_start;
269 * Read the current TLS pointer from tpidr_el0 as it may be
270 * out-of-sync with the saved value.
272 asm("mrs %0, tpidr_el0" : "=r" (tls));
274 /* 16-byte aligned stack mandatory on AArch64 */
275 if (stack_start & 15)
277 childregs->sp = stack_start;
281 * If a TLS pointer was passed to clone (4th argument), use it
282 * for the new thread.
284 if (clone_flags & CLONE_SETTLS)
285 tls = childregs->regs[3];
287 memset(childregs, 0, sizeof(struct pt_regs));
288 childregs->pstate = PSR_MODE_EL1h;
289 p->thread.cpu_context.x19 = stack_start;
290 p->thread.cpu_context.x20 = stk_sz;
292 p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
293 p->thread.cpu_context.sp = (unsigned long)childregs;
294 p->thread.tp_value = tls;
296 ptrace_hw_copy_thread(p);
301 static void tls_thread_switch(struct task_struct *next)
303 unsigned long tpidr, tpidrro;
305 if (!is_compat_task()) {
306 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
307 current->thread.tp_value = tpidr;
310 if (is_compat_thread(task_thread_info(next))) {
312 tpidrro = next->thread.tp_value;
314 tpidr = next->thread.tp_value;
319 " msr tpidr_el0, %0\n"
320 " msr tpidrro_el0, %1"
321 : : "r" (tpidr), "r" (tpidrro));
327 struct task_struct *__switch_to(struct task_struct *prev,
328 struct task_struct *next)
330 struct task_struct *last;
332 fpsimd_thread_switch(next);
333 tls_thread_switch(next);
334 hw_breakpoint_thread_switch(next);
335 contextidr_thread_switch(next);
338 * Complete any pending TLB or cache maintenance on this CPU in case
339 * the thread migrates to a different CPU.
343 /* the actual thread switch */
344 last = cpu_switch_to(prev, next);
349 unsigned long get_wchan(struct task_struct *p)
351 struct stackframe frame;
352 unsigned long stack_page;
354 if (!p || p == current || p->state == TASK_RUNNING)
357 frame.fp = thread_saved_fp(p);
358 frame.sp = thread_saved_sp(p);
359 frame.pc = thread_saved_pc(p);
360 stack_page = (unsigned long)task_stack_page(p);
362 if (frame.sp < stack_page ||
363 frame.sp >= stack_page + THREAD_SIZE ||
364 unwind_frame(&frame))
366 if (!in_sched_functions(frame.pc))
368 } while (count ++ < 16);
372 unsigned long arch_align_stack(unsigned long sp)
374 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
375 sp -= get_random_int() & ~PAGE_MASK;
379 static unsigned long randomize_base(unsigned long base)
381 unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
382 return randomize_range(base, range_end, 0) ? : base;
385 unsigned long arch_randomize_brk(struct mm_struct *mm)
387 return randomize_base(mm->brk);