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/export.h>
25 #include <linux/sched.h>
26 #include <linux/kernel.h>
28 #include <linux/stddef.h>
29 #include <linux/unistd.h>
30 #include <linux/user.h>
31 #include <linux/delay.h>
32 #include <linux/reboot.h>
33 #include <linux/interrupt.h>
34 #include <linux/kallsyms.h>
35 #include <linux/init.h>
36 #include <linux/cpu.h>
37 #include <linux/elfcore.h>
39 #include <linux/tick.h>
40 #include <linux/utsname.h>
41 #include <linux/uaccess.h>
42 #include <linux/random.h>
43 #include <linux/hw_breakpoint.h>
44 #include <linux/personality.h>
45 #include <linux/notifier.h>
47 #include <asm/compat.h>
48 #include <asm/cacheflush.h>
49 #include <asm/fpsimd.h>
50 #include <asm/mmu_context.h>
51 #include <asm/processor.h>
52 #include <asm/stacktrace.h>
54 #ifdef CONFIG_CC_STACKPROTECTOR
55 #include <linux/stackprotector.h>
56 unsigned long __stack_chk_guard __read_mostly
;
57 EXPORT_SYMBOL(__stack_chk_guard
);
60 void soft_restart(unsigned long addr
)
62 setup_mm_for_reboot();
63 cpu_soft_restart(virt_to_phys(cpu_reset
), addr
);
64 /* Should never get here */
69 * Function pointers to optional machine specific functions
71 void (*pm_power_off
)(void);
72 EXPORT_SYMBOL_GPL(pm_power_off
);
74 void (*arm_pm_restart
)(enum reboot_mode reboot_mode
, const char *cmd
);
77 * This is our default idle handler.
79 void arch_cpu_idle(void)
82 * This should do all the clock switching and wait for interrupt
89 #ifdef CONFIG_HOTPLUG_CPU
90 void arch_cpu_idle_dead(void)
97 * Called by kexec, immediately prior to machine_kexec().
99 * This must completely disable all secondary CPUs; simply causing those CPUs
100 * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
101 * kexec'd kernel to use any and all RAM as it sees fit, without having to
102 * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
103 * functionality embodied in disable_nonboot_cpus() to achieve this.
105 void machine_shutdown(void)
107 disable_nonboot_cpus();
111 * Halting simply requires that the secondary CPUs stop performing any
112 * activity (executing tasks, handling interrupts). smp_send_stop()
115 void machine_halt(void)
123 * Power-off simply requires that the secondary CPUs stop performing any
124 * activity (executing tasks, handling interrupts). smp_send_stop()
125 * achieves this. When the system power is turned off, it will take all CPUs
128 void machine_power_off(void)
137 * Restart requires that the secondary CPUs stop performing any activity
138 * while the primary CPU resets the system. Systems with a single CPU can
139 * use soft_restart() as their machine descriptor's .restart hook, since that
140 * will cause the only available CPU to reset. Systems with multiple CPUs must
141 * provide a HW restart implementation, to ensure that all CPUs reset at once.
142 * This is required so that any code running after reset on the primary CPU
143 * doesn't have to co-ordinate with other CPUs to ensure they aren't still
144 * executing pre-reset code, and using RAM that the primary CPU's code wishes
145 * to use. Implementing such co-ordination would be essentially impossible.
147 void machine_restart(char *cmd
)
149 /* Disable interrupts first */
153 /* Now call the architecture specific reboot code. */
155 arm_pm_restart(reboot_mode
, cmd
);
157 do_kernel_restart(cmd
);
160 * Whoops - the architecture was unable to reboot.
162 printk("Reboot failed -- System halted\n");
166 void __show_regs(struct pt_regs
*regs
)
171 if (compat_user_mode(regs
)) {
172 lr
= regs
->compat_lr
;
173 sp
= regs
->compat_sp
;
181 show_regs_print_info(KERN_DEFAULT
);
182 print_symbol("PC is at %s\n", instruction_pointer(regs
));
183 print_symbol("LR is at %s\n", lr
);
184 printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
185 regs
->pc
, lr
, regs
->pstate
);
186 printk("sp : %016llx\n", sp
);
187 for (i
= top_reg
; i
>= 0; i
--) {
188 printk("x%-2d: %016llx ", i
, regs
->regs
[i
]);
195 void show_regs(struct pt_regs
* regs
)
202 * Free current thread data structures etc..
204 void exit_thread(void)
208 static void tls_thread_flush(void)
210 asm ("msr tpidr_el0, xzr");
212 if (is_compat_task()) {
213 current
->thread
.tp_value
= 0;
216 * We need to ensure ordering between the shadow state and the
217 * hardware state, so that we don't corrupt the hardware state
218 * with a stale shadow state during context switch.
221 asm ("msr tpidrro_el0, xzr");
225 void flush_thread(void)
227 fpsimd_flush_thread();
229 flush_ptrace_hw_breakpoint(current
);
232 void release_thread(struct task_struct
*dead_task
)
236 int arch_dup_task_struct(struct task_struct
*dst
, struct task_struct
*src
)
238 fpsimd_preserve_current_state();
243 asmlinkage
void ret_from_fork(void) asm("ret_from_fork");
245 int copy_thread(unsigned long clone_flags
, unsigned long stack_start
,
246 unsigned long stk_sz
, struct task_struct
*p
)
248 struct pt_regs
*childregs
= task_pt_regs(p
);
249 unsigned long tls
= p
->thread
.tp_value
;
251 memset(&p
->thread
.cpu_context
, 0, sizeof(struct cpu_context
));
253 if (likely(!(p
->flags
& PF_KTHREAD
))) {
254 *childregs
= *current_pt_regs();
255 childregs
->regs
[0] = 0;
256 if (is_compat_thread(task_thread_info(p
))) {
258 childregs
->compat_sp
= stack_start
;
261 * Read the current TLS pointer from tpidr_el0 as it may be
262 * out-of-sync with the saved value.
264 asm("mrs %0, tpidr_el0" : "=r" (tls
));
266 /* 16-byte aligned stack mandatory on AArch64 */
267 if (stack_start
& 15)
269 childregs
->sp
= stack_start
;
273 * If a TLS pointer was passed to clone (4th argument), use it
274 * for the new thread.
276 if (clone_flags
& CLONE_SETTLS
)
277 tls
= childregs
->regs
[3];
279 memset(childregs
, 0, sizeof(struct pt_regs
));
280 childregs
->pstate
= PSR_MODE_EL1h
;
281 p
->thread
.cpu_context
.x19
= stack_start
;
282 p
->thread
.cpu_context
.x20
= stk_sz
;
284 p
->thread
.cpu_context
.pc
= (unsigned long)ret_from_fork
;
285 p
->thread
.cpu_context
.sp
= (unsigned long)childregs
;
286 p
->thread
.tp_value
= tls
;
288 ptrace_hw_copy_thread(p
);
293 static void tls_thread_switch(struct task_struct
*next
)
295 unsigned long tpidr
, tpidrro
;
297 if (!is_compat_task()) {
298 asm("mrs %0, tpidr_el0" : "=r" (tpidr
));
299 current
->thread
.tp_value
= tpidr
;
302 if (is_compat_thread(task_thread_info(next
))) {
304 tpidrro
= next
->thread
.tp_value
;
306 tpidr
= next
->thread
.tp_value
;
311 " msr tpidr_el0, %0\n"
312 " msr tpidrro_el0, %1"
313 : : "r" (tpidr
), "r" (tpidrro
));
319 struct task_struct
*__switch_to(struct task_struct
*prev
,
320 struct task_struct
*next
)
322 struct task_struct
*last
;
324 fpsimd_thread_switch(next
);
325 tls_thread_switch(next
);
326 hw_breakpoint_thread_switch(next
);
327 contextidr_thread_switch(next
);
330 * Complete any pending TLB or cache maintenance on this CPU in case
331 * the thread migrates to a different CPU.
335 /* the actual thread switch */
336 last
= cpu_switch_to(prev
, next
);
341 unsigned long get_wchan(struct task_struct
*p
)
343 struct stackframe frame
;
344 unsigned long stack_page
;
346 if (!p
|| p
== current
|| p
->state
== TASK_RUNNING
)
349 frame
.fp
= thread_saved_fp(p
);
350 frame
.sp
= thread_saved_sp(p
);
351 frame
.pc
= thread_saved_pc(p
);
352 stack_page
= (unsigned long)task_stack_page(p
);
354 if (frame
.sp
< stack_page
||
355 frame
.sp
>= stack_page
+ THREAD_SIZE
||
356 unwind_frame(&frame
))
358 if (!in_sched_functions(frame
.pc
))
360 } while (count
++ < 16);
364 unsigned long arch_align_stack(unsigned long sp
)
366 if (!(current
->personality
& ADDR_NO_RANDOMIZE
) && randomize_va_space
)
367 sp
-= get_random_int() & ~PAGE_MASK
;
371 static unsigned long randomize_base(unsigned long base
)
373 unsigned long range_end
= base
+ (STACK_RND_MASK
<< PAGE_SHIFT
) + 1;
374 return randomize_range(base
, range_end
, 0) ? : base
;
377 unsigned long arch_randomize_brk(struct mm_struct
*mm
)
379 return randomize_base(mm
->brk
);