Merge branch 'omap-serial' of git://git.linaro.org/people/rmk/linux-arm
[~shefty/rdma-dev.git] / arch / arm64 / kernel / process.c
1 /*
2  * Based on arch/arm/kernel/process.c
3  *
4  * Original Copyright (C) 1995  Linus Torvalds
5  * Copyright (C) 1996-2000 Russell King - Converted to ARM.
6  * Copyright (C) 2012 ARM Ltd.
7  *
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.
11  *
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.
16  *
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/>.
19  */
20
21 #include <stdarg.h>
22
23 #include <linux/export.h>
24 #include <linux/sched.h>
25 #include <linux/kernel.h>
26 #include <linux/mm.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>
37 #include <linux/pm.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>
45
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>
51
52 static void setup_restart(void)
53 {
54         /*
55          * Tell the mm system that we are going to reboot -
56          * we may need it to insert some 1:1 mappings so that
57          * soft boot works.
58          */
59         setup_mm_for_reboot();
60
61         /* Clean and invalidate caches */
62         flush_cache_all();
63
64         /* Turn D-cache off */
65         cpu_cache_off();
66
67         /* Push out any further dirty data, and ensure cache is empty */
68         flush_cache_all();
69 }
70
71 void soft_restart(unsigned long addr)
72 {
73         setup_restart();
74         cpu_reset(addr);
75 }
76
77 /*
78  * Function pointers to optional machine specific functions
79  */
80 void (*pm_power_off)(void);
81 EXPORT_SYMBOL_GPL(pm_power_off);
82
83 void (*pm_restart)(const char *cmd);
84 EXPORT_SYMBOL_GPL(pm_restart);
85
86
87 /*
88  * This is our default idle handler.
89  */
90 static void default_idle(void)
91 {
92         /*
93          * This should do all the clock switching and wait for interrupt
94          * tricks
95          */
96         cpu_do_idle();
97         local_irq_enable();
98 }
99
100 void (*pm_idle)(void) = default_idle;
101 EXPORT_SYMBOL_GPL(pm_idle);
102
103 /*
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.
108  */
109 void cpu_idle(void)
110 {
111         local_fiq_enable();
112
113         /* endless idle loop with no priority at all */
114         while (1) {
115                 tick_nohz_idle_enter();
116                 rcu_idle_enter();
117                 while (!need_resched()) {
118                         /*
119                          * We need to disable interrupts here to ensure
120                          * we don't miss a wakeup call.
121                          */
122                         local_irq_disable();
123                         if (!need_resched()) {
124                                 stop_critical_timings();
125                                 pm_idle();
126                                 start_critical_timings();
127                                 /*
128                                  * pm_idle functions should always return
129                                  * with IRQs enabled.
130                                  */
131                                 WARN_ON(irqs_disabled());
132                         } else {
133                                 local_irq_enable();
134                         }
135                 }
136                 rcu_idle_exit();
137                 tick_nohz_idle_exit();
138                 schedule_preempt_disabled();
139         }
140 }
141
142 void machine_shutdown(void)
143 {
144 #ifdef CONFIG_SMP
145         smp_send_stop();
146 #endif
147 }
148
149 void machine_halt(void)
150 {
151         machine_shutdown();
152         while (1);
153 }
154
155 void machine_power_off(void)
156 {
157         machine_shutdown();
158         if (pm_power_off)
159                 pm_power_off();
160 }
161
162 void machine_restart(char *cmd)
163 {
164         machine_shutdown();
165
166         /* Disable interrupts first */
167         local_irq_disable();
168         local_fiq_disable();
169
170         /* Now call the architecture specific reboot code. */
171         if (pm_restart)
172                 pm_restart(cmd);
173
174         /*
175          * Whoops - the architecture was unable to reboot.
176          */
177         printk("Reboot failed -- System halted\n");
178         while (1);
179 }
180
181 void __show_regs(struct pt_regs *regs)
182 {
183         int i;
184
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]);
197                 if (i % 2 == 0)
198                         printk("\n");
199         }
200         printk("\n");
201 }
202
203 void show_regs(struct pt_regs * regs)
204 {
205         printk("\n");
206         printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
207         __show_regs(regs);
208 }
209
210 /*
211  * Free current thread data structures etc..
212  */
213 void exit_thread(void)
214 {
215 }
216
217 void flush_thread(void)
218 {
219         fpsimd_flush_thread();
220         flush_ptrace_hw_breakpoint(current);
221 }
222
223 void release_thread(struct task_struct *dead_task)
224 {
225 }
226
227 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
228 {
229         fpsimd_save_state(&current->thread.fpsimd_state);
230         *dst = *src;
231         return 0;
232 }
233
234 asmlinkage void ret_from_fork(void) asm("ret_from_fork");
235
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)
239 {
240         struct pt_regs *childregs = task_pt_regs(p);
241         unsigned long tls = p->thread.tp_value;
242
243         *childregs = *regs;
244         childregs->regs[0] = 0;
245
246         if (is_compat_thread(task_thread_info(p)))
247                 childregs->compat_sp = stack_start;
248         else {
249                 /*
250                  * Read the current TLS pointer from tpidr_el0 as it may be
251                  * out-of-sync with the saved value.
252                  */
253                 asm("mrs %0, tpidr_el0" : "=r" (tls));
254                 childregs->sp = stack_start;
255         }
256
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;
260
261         /* If a TLS pointer was passed to clone, use that for the new thread. */
262         if (clone_flags & CLONE_SETTLS)
263                 tls = regs->regs[3];
264         p->thread.tp_value = tls;
265
266         ptrace_hw_copy_thread(p);
267
268         return 0;
269 }
270
271 static void tls_thread_switch(struct task_struct *next)
272 {
273         unsigned long tpidr, tpidrro;
274
275         if (!is_compat_task()) {
276                 asm("mrs %0, tpidr_el0" : "=r" (tpidr));
277                 current->thread.tp_value = tpidr;
278         }
279
280         if (is_compat_thread(task_thread_info(next))) {
281                 tpidr = 0;
282                 tpidrro = next->thread.tp_value;
283         } else {
284                 tpidr = next->thread.tp_value;
285                 tpidrro = 0;
286         }
287
288         asm(
289         "       msr     tpidr_el0, %0\n"
290         "       msr     tpidrro_el0, %1"
291         : : "r" (tpidr), "r" (tpidrro));
292 }
293
294 /*
295  * Thread switching.
296  */
297 struct task_struct *__switch_to(struct task_struct *prev,
298                                 struct task_struct *next)
299 {
300         struct task_struct *last;
301
302         fpsimd_thread_switch(next);
303         tls_thread_switch(next);
304         hw_breakpoint_thread_switch(next);
305
306         /* the actual thread switch */
307         last = cpu_switch_to(prev, next);
308
309         return last;
310 }
311
312 /*
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.
316  */
317 extern void kernel_thread_helper(void);
318 asm(    ".section .text\n"
319 "       .align\n"
320 "       .type   kernel_thread_helper, #function\n"
321 "kernel_thread_helper:\n"
322 "       mov     x0, x1\n"
323 "       mov     x30, x3\n"
324 "       br      x2\n"
325 "       .size   kernel_thread_helper, . - kernel_thread_helper\n"
326 "       .previous");
327
328 #define kernel_thread_exit      do_exit
329
330 /*
331  * Create a kernel thread.
332  */
333 pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
334 {
335         struct pt_regs regs;
336
337         memset(&regs, 0, sizeof(regs));
338
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;
344
345         return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 0, NULL, NULL);
346 }
347 EXPORT_SYMBOL(kernel_thread);
348
349 unsigned long get_wchan(struct task_struct *p)
350 {
351         struct stackframe frame;
352         int count = 0;
353         if (!p || p == current || p->state == TASK_RUNNING)
354                 return 0;
355
356         frame.fp = thread_saved_fp(p);
357         frame.sp = thread_saved_sp(p);
358         frame.pc = thread_saved_pc(p);
359         do {
360                 int ret = unwind_frame(&frame);
361                 if (ret < 0)
362                         return 0;
363                 if (!in_sched_functions(frame.pc))
364                         return frame.pc;
365         } while (count ++ < 16);
366         return 0;
367 }
368
369 unsigned long arch_align_stack(unsigned long sp)
370 {
371         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
372                 sp -= get_random_int() & ~PAGE_MASK;
373         return sp & ~0xf;
374 }
375
376 static unsigned long randomize_base(unsigned long base)
377 {
378         unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
379         return randomize_range(base, range_end, 0) ? : base;
380 }
381
382 unsigned long arch_randomize_brk(struct mm_struct *mm)
383 {
384         return randomize_base(mm->brk);
385 }
386
387 unsigned long randomize_et_dyn(unsigned long base)
388 {
389         return randomize_base(base);
390 }