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/export.h>
24 #include <linux/sched.h>
25 #include <linux/kernel.h>
27 #include <linux/stddef.h>
28 #include <linux/unistd.h>
29 #include <linux/user.h>
30 #include <linux/delay.h>
31 #include <linux/reboot.h>
32 #include <linux/interrupt.h>
33 #include <linux/kallsyms.h>
34 #include <linux/init.h>
35 #include <linux/cpu.h>
36 #include <linux/elfcore.h>
38 #include <linux/tick.h>
39 #include <linux/utsname.h>
40 #include <linux/uaccess.h>
41 #include <linux/random.h>
42 #include <linux/hw_breakpoint.h>
43 #include <linux/personality.h>
44 #include <linux/notifier.h>
46 #include <asm/compat.h>
47 #include <asm/cacheflush.h>
48 #include <asm/processor.h>
49 #include <asm/stacktrace.h>
50 #include <asm/fpsimd.h>
52 static void setup_restart(void)
55 * Tell the mm system that we are going to reboot -
56 * we may need it to insert some 1:1 mappings so that
59 setup_mm_for_reboot();
61 /* Clean and invalidate caches */
64 /* Turn D-cache off */
67 /* Push out any further dirty data, and ensure cache is empty */
71 void soft_restart(unsigned long addr)
78 * Function pointers to optional machine specific functions
80 void (*pm_power_off)(void);
81 EXPORT_SYMBOL_GPL(pm_power_off);
83 void (*pm_restart)(const char *cmd);
84 EXPORT_SYMBOL_GPL(pm_restart);
88 * This is our default idle handler.
90 static void default_idle(void)
93 * This should do all the clock switching and wait for interrupt
100 void (*pm_idle)(void) = default_idle;
101 EXPORT_SYMBOL_GPL(pm_idle);
104 * The idle thread, has rather strange semantics for calling pm_idle,
105 * but this is what x86 does and we need to do the same, so that
106 * things like cpuidle get called in the same way. The only difference
107 * is that we always respect 'hlt_counter' to prevent low power idle.
113 /* endless idle loop with no priority at all */
115 tick_nohz_idle_enter();
117 while (!need_resched()) {
119 * We need to disable interrupts here to ensure
120 * we don't miss a wakeup call.
123 if (!need_resched()) {
124 stop_critical_timings();
126 start_critical_timings();
128 * pm_idle functions should always return
131 WARN_ON(irqs_disabled());
137 tick_nohz_idle_exit();
138 schedule_preempt_disabled();
142 void machine_shutdown(void)
149 void machine_halt(void)
155 void machine_power_off(void)
162 void machine_restart(char *cmd)
166 /* Disable interrupts first */
170 /* Now call the architecture specific reboot code. */
175 * Whoops - the architecture was unable to reboot.
177 printk("Reboot failed -- System halted\n");
181 void __show_regs(struct pt_regs *regs)
185 printk("CPU: %d %s (%s %.*s)\n",
186 raw_smp_processor_id(), print_tainted(),
187 init_utsname()->release,
188 (int)strcspn(init_utsname()->version, " "),
189 init_utsname()->version);
190 print_symbol("PC is at %s\n", instruction_pointer(regs));
191 print_symbol("LR is at %s\n", regs->regs[30]);
192 printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
193 regs->pc, regs->regs[30], regs->pstate);
194 printk("sp : %016llx\n", regs->sp);
195 for (i = 29; i >= 0; i--) {
196 printk("x%-2d: %016llx ", i, regs->regs[i]);
203 void show_regs(struct pt_regs * regs)
206 printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
211 * Free current thread data structures etc..
213 void exit_thread(void)
217 void flush_thread(void)
219 fpsimd_flush_thread();
220 flush_ptrace_hw_breakpoint(current);
223 void release_thread(struct task_struct *dead_task)
227 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
229 fpsimd_save_state(¤t->thread.fpsimd_state);
234 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
236 int copy_thread(unsigned long clone_flags, unsigned long stack_start,
237 unsigned long stk_sz, struct task_struct *p,
238 struct pt_regs *regs)
240 struct pt_regs *childregs = task_pt_regs(p);
241 unsigned long tls = p->thread.tp_value;
244 childregs->regs[0] = 0;
246 if (is_compat_thread(task_thread_info(p)))
247 childregs->compat_sp = stack_start;
250 * Read the current TLS pointer from tpidr_el0 as it may be
251 * out-of-sync with the saved value.
253 asm("mrs %0, tpidr_el0" : "=r" (tls));
254 childregs->sp = stack_start;
257 memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
258 p->thread.cpu_context.sp = (unsigned long)childregs;
259 p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
261 /* If a TLS pointer was passed to clone, use that for the new thread. */
262 if (clone_flags & CLONE_SETTLS)
264 p->thread.tp_value = tls;
266 ptrace_hw_copy_thread(p);
271 static void tls_thread_switch(struct task_struct *next)
273 unsigned long tpidr, tpidrro;
275 if (!is_compat_task()) {
276 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
277 current->thread.tp_value = tpidr;
280 if (is_compat_thread(task_thread_info(next))) {
282 tpidrro = next->thread.tp_value;
284 tpidr = next->thread.tp_value;
289 " msr tpidr_el0, %0\n"
290 " msr tpidrro_el0, %1"
291 : : "r" (tpidr), "r" (tpidrro));
297 struct task_struct *__switch_to(struct task_struct *prev,
298 struct task_struct *next)
300 struct task_struct *last;
302 fpsimd_thread_switch(next);
303 tls_thread_switch(next);
304 hw_breakpoint_thread_switch(next);
306 /* the actual thread switch */
307 last = cpu_switch_to(prev, next);
313 * Shuffle the argument into the correct register before calling the
314 * thread function. x1 is the thread argument, x2 is the pointer to
315 * the thread function, and x3 points to the exit function.
317 extern void kernel_thread_helper(void);
318 asm( ".section .text\n"
320 " .type kernel_thread_helper, #function\n"
321 "kernel_thread_helper:\n"
325 " .size kernel_thread_helper, . - kernel_thread_helper\n"
328 #define kernel_thread_exit do_exit
331 * Create a kernel thread.
333 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
337 memset(®s, 0, sizeof(regs));
339 regs.regs[1] = (unsigned long)arg;
340 regs.regs[2] = (unsigned long)fn;
341 regs.regs[3] = (unsigned long)kernel_thread_exit;
342 regs.pc = (unsigned long)kernel_thread_helper;
343 regs.pstate = PSR_MODE_EL1h;
345 return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
347 EXPORT_SYMBOL(kernel_thread);
349 unsigned long get_wchan(struct task_struct *p)
351 struct stackframe frame;
353 if (!p || p == current || p->state == TASK_RUNNING)
356 frame.fp = thread_saved_fp(p);
357 frame.sp = thread_saved_sp(p);
358 frame.pc = thread_saved_pc(p);
360 int ret = unwind_frame(&frame);
363 if (!in_sched_functions(frame.pc))
365 } while (count ++ < 16);
369 unsigned long arch_align_stack(unsigned long sp)
371 if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
372 sp -= get_random_int() & ~PAGE_MASK;
376 static unsigned long randomize_base(unsigned long base)
378 unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
379 return randomize_range(base, range_end, 0) ? : base;
382 unsigned long arch_randomize_brk(struct mm_struct *mm)
384 return randomize_base(mm->brk);
387 unsigned long randomize_et_dyn(unsigned long base)
389 return randomize_base(base);