/*
* Based on arch/arm/kernel/process.c
*
* Original Copyright (C) 1995 Linus Torvalds
* Copyright (C) 1996-2000 Russell King - Converted to ARM.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdarg.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/user.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/elfcore.h>
#include <linux/pm.h>
#include <linux/tick.h>
#include <linux/utsname.h>
#include <linux/uaccess.h>
#include <linux/random.h>
#include <linux/hw_breakpoint.h>
#include <linux/personality.h>
#include <linux/notifier.h>
#include <asm/compat.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/stacktrace.h>
#include <asm/fpsimd.h>
static void setup_restart(void)
{
/*
* Tell the mm system that we are going to reboot -
* we may need it to insert some 1:1 mappings so that
* soft boot works.
*/
setup_mm_for_reboot();
/* Clean and invalidate caches */
flush_cache_all();
/* Turn D-cache off */
cpu_cache_off();
/* Push out any further dirty data, and ensure cache is empty */
flush_cache_all();
}
void soft_restart(unsigned long addr)
{
setup_restart();
cpu_reset(addr);
}
/*
* Function pointers to optional machine specific functions
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL_GPL(pm_power_off);
void (*pm_restart)(const char *cmd);
EXPORT_SYMBOL_GPL(pm_restart);
/*
* This is our default idle handler.
*/
static void default_idle(void)
{
/*
* This should do all the clock switching and wait for interrupt
* tricks
*/
cpu_do_idle();
local_irq_enable();
}
void (*pm_idle)(void) = default_idle;
EXPORT_SYMBOL_GPL(pm_idle);
/*
* The idle thread, has rather strange semantics for calling pm_idle,
* but this is what x86 does and we need to do the same, so that
* things like cpuidle get called in the same way. The only difference
* is that we always respect 'hlt_counter' to prevent low power idle.
*/
void cpu_idle(void)
{
local_fiq_enable();
/* endless idle loop with no priority at all */
while (1) {
tick_nohz_idle_enter();
rcu_idle_enter();
while (!need_resched()) {
/*
* We need to disable interrupts here to ensure
* we don't miss a wakeup call.
*/
local_irq_disable();
if (!need_resched()) {
stop_critical_timings();
pm_idle();
start_critical_timings();
/*
* pm_idle functions should always return
* with IRQs enabled.
*/
WARN_ON(irqs_disabled());
} else {
local_irq_enable();
}
}
rcu_idle_exit();
tick_nohz_idle_exit();
schedule_preempt_disabled();
}
}
void machine_shutdown(void)
{
#ifdef CONFIG_SMP
smp_send_stop();
#endif
}
void machine_halt(void)
{
machine_shutdown();
while (1);
}
void machine_power_off(void)
{
machine_shutdown();
if (pm_power_off)
pm_power_off();
}
void machine_restart(char *cmd)
{
machine_shutdown();
/* Disable interrupts first */
local_irq_disable();
local_fiq_disable();
/* Now call the architecture specific reboot code. */
if (pm_restart)
pm_restart(cmd);
/*
* Whoops - the architecture was unable to reboot.
*/
printk("Reboot failed -- System halted\n");
while (1);
}
void __show_regs(struct pt_regs *regs)
{
int i;
printk("CPU: %d %s (%s %.*s)\n",
raw_smp_processor_id(), print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
print_symbol("PC is at %s\n", instruction_pointer(regs));
print_symbol("LR is at %s\n", regs->regs[30]);
printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
regs->pc, regs->regs[30], regs->pstate);
printk("sp : %016llx\n", regs->sp);
for (i = 29; i >= 0; i--) {
printk("x%-2d: %016llx ", i, regs->regs[i]);
if (i % 2 == 0)
printk("\n");
}
printk("\n");
}
void show_regs(struct pt_regs * regs)
{
printk("\n");
printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
__show_regs(regs);
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
}
void flush_thread(void)
{
fpsimd_flush_thread();
flush_ptrace_hw_breakpoint(current);
}
void release_thread(struct task_struct *dead_task)
{
}
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
fpsimd_save_state(¤t->thread.fpsimd_state);
*dst = *src;
return 0;
}
asmlinkage void ret_from_fork(void) asm("ret_from_fork");
int copy_thread(unsigned long clone_flags, unsigned long stack_start,
unsigned long stk_sz, struct task_struct *p,
struct pt_regs *regs)
{
struct pt_regs *childregs = task_pt_regs(p);
unsigned long tls = p->thread.tp_value;
*childregs = *regs;
childregs->regs[0] = 0;
if (is_compat_thread(task_thread_info(p)))
childregs->compat_sp = stack_start;
else {
/*
* Read the current TLS pointer from tpidr_el0 as it may be
* out-of-sync with the saved value.
*/
asm("mrs %0, tpidr_el0" : "=r" (tls));
childregs->sp = stack_start;
}
memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
p->thread.cpu_context.sp = (unsigned long)childregs;
p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
/* If a TLS pointer was passed to clone, use that for the new thread. */
if (clone_flags & CLONE_SETTLS)
tls = regs->regs[3];
p->thread.tp_value = tls;
ptrace_hw_copy_thread(p);
return 0;
}
static void tls_thread_switch(struct task_struct *next)
{
unsigned long tpidr, tpidrro;
if (!is_compat_task()) {
asm("mrs %0, tpidr_el0" : "=r" (tpidr));
current->thread.tp_value = tpidr;
}
if (is_compat_thread(task_thread_info(next))) {
tpidr = 0;
tpidrro = next->thread.tp_value;
} else {
tpidr = next->thread.tp_value;
tpidrro = 0;
}
asm(
" msr tpidr_el0, %0\n"
" msr tpidrro_el0, %1"
: : "r" (tpidr), "r" (tpidrro));
}
/*
* Thread switching.
*/
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *next)
{
struct task_struct *last;
fpsimd_thread_switch(next);
tls_thread_switch(next);
hw_breakpoint_thread_switch(next);
/* the actual thread switch */
last = cpu_switch_to(prev, next);
return last;
}
/*
* Shuffle the argument into the correct register before calling the
* thread function. x1 is the thread argument, x2 is the pointer to
* the thread function, and x3 points to the exit function.
*/
extern void kernel_thread_helper(void);
asm( ".section .text\n"
" .align\n"
" .type kernel_thread_helper, #function\n"
"kernel_thread_helper:\n"
" mov x0, x1\n"
" mov x30, x3\n"
" br x2\n"
" .size kernel_thread_helper, . - kernel_thread_helper\n"
" .previous");
#define kernel_thread_exit do_exit
/*
* Create a kernel thread.
*/
pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(®s, 0, sizeof(regs));
regs.regs[1] = (unsigned long)arg;
regs.regs[2] = (unsigned long)fn;
regs.regs[3] = (unsigned long)kernel_thread_exit;
regs.pc = (unsigned long)kernel_thread_helper;
regs.pstate = PSR_MODE_EL1h;
return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, ®s, 0, NULL, NULL);
}
EXPORT_SYMBOL(kernel_thread);
unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
frame.fp = thread_saved_fp(p);
frame.sp = thread_saved_sp(p);
frame.pc = thread_saved_pc(p);
do {
int ret = unwind_frame(&frame);
if (ret < 0)
return 0;
if (!in_sched_functions(frame.pc))
return frame.pc;
} while (count ++ < 16);
return 0;
}
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
sp -= get_random_int() & ~PAGE_MASK;
return sp & ~0xf;
}
static unsigned long randomize_base(unsigned long base)
{
unsigned long range_end = base + (STACK_RND_MASK << PAGE_SHIFT) + 1;
return randomize_range(base, range_end, 0) ? : base;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
return randomize_base(mm->brk);
}
unsigned long randomize_et_dyn(unsigned long base)
{
return randomize_base(base);
}
