blob: 929b6356abff87cc31508dce0d6b007b940de783 [file] [log] [blame]
/*
* 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/compat.h>
#include <linux/efi.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/fpsimd.h>
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/stacktrace.h>
#ifdef CONFIG_CC_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif
void soft_restart(unsigned long addr)
{
setup_mm_for_reboot();
cpu_soft_restart(virt_to_phys(cpu_reset), addr);
/* Should never get here */
BUG();
}
/*
* Function pointers to optional machine specific functions
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL_GPL(pm_power_off);
void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd);
/*
* This is our default idle handler.
*/
void arch_cpu_idle(void)
{
/*
* This should do all the clock switching and wait for interrupt
* tricks
*/
cpu_do_idle();
local_irq_enable();
}
#ifdef CONFIG_HOTPLUG_CPU
void arch_cpu_idle_dead(void)
{
cpu_die();
}
#endif
/*
* Called by kexec, immediately prior to machine_kexec().
*
* This must completely disable all secondary CPUs; simply causing those CPUs
* to execute e.g. a RAM-based pin loop is not sufficient. This allows the
* kexec'd kernel to use any and all RAM as it sees fit, without having to
* avoid any code or data used by any SW CPU pin loop. The CPU hotplug
* functionality embodied in disable_nonboot_cpus() to achieve this.
*/
void machine_shutdown(void)
{
disable_nonboot_cpus();
}
/*
* Halting simply requires that the secondary CPUs stop performing any
* activity (executing tasks, handling interrupts). smp_send_stop()
* achieves this.
*/
void machine_halt(void)
{
local_irq_disable();
smp_send_stop();
while (1);
}
/*
* Power-off simply requires that the secondary CPUs stop performing any
* activity (executing tasks, handling interrupts). smp_send_stop()
* achieves this. When the system power is turned off, it will take all CPUs
* with it.
*/
void machine_power_off(void)
{
local_irq_disable();
smp_send_stop();
if (pm_power_off)
pm_power_off();
}
/*
* Restart requires that the secondary CPUs stop performing any activity
* while the primary CPU resets the system. Systems with a single CPU can
* use soft_restart() as their machine descriptor's .restart hook, since that
* will cause the only available CPU to reset. Systems with multiple CPUs must
* provide a HW restart implementation, to ensure that all CPUs reset at once.
* This is required so that any code running after reset on the primary CPU
* doesn't have to co-ordinate with other CPUs to ensure they aren't still
* executing pre-reset code, and using RAM that the primary CPU's code wishes
* to use. Implementing such co-ordination would be essentially impossible.
*/
void machine_restart(char *cmd)
{
/* Disable interrupts first */
local_irq_disable();
smp_send_stop();
/*
* UpdateCapsule() depends on the system being reset via
* ResetSystem().
*/
if (efi_enabled(EFI_RUNTIME_SERVICES))
efi_reboot(reboot_mode, NULL);
/* Now call the architecture specific reboot code. */
if (arm_pm_restart)
arm_pm_restart(reboot_mode, cmd);
else
do_kernel_restart(cmd);
/*
* Whoops - the architecture was unable to reboot.
*/
printk("Reboot failed -- System halted\n");
while (1);
}
/*
* dump a block of kernel memory from around the given address
*/
static void show_data(unsigned long addr, int nbytes, const char *name)
{
int i, j;
int nlines;
u32 *p;
/*
* don't attempt to dump non-kernel addresses or
* values that are probably just small negative numbers
*/
if (addr < PAGE_OFFSET || addr > -256UL)
return;
printk("\n%s: %#lx:\n", name, addr);
/*
* round address down to a 32 bit boundary
* and always dump a multiple of 32 bytes
*/
p = (u32 *)(addr & ~(sizeof(u32) - 1));
nbytes += (addr & (sizeof(u32) - 1));
nlines = (nbytes + 31) / 32;
for (i = 0; i < nlines; i++) {
/*
* just display low 16 bits of address to keep
* each line of the dump < 80 characters
*/
printk("%04lx ", (unsigned long)p & 0xffff);
for (j = 0; j < 8; j++) {
u32 data;
if (probe_kernel_address(p, data)) {
printk(" ********");
} else {
printk(" %08x", data);
}
++p;
}
printk("\n");
}
}
static void show_extra_register_data(struct pt_regs *regs, int nbytes)
{
mm_segment_t fs;
unsigned int i;
fs = get_fs();
set_fs(KERNEL_DS);
show_data(regs->pc - nbytes, nbytes * 2, "PC");
show_data(regs->regs[30] - nbytes, nbytes * 2, "LR");
show_data(regs->sp - nbytes, nbytes * 2, "SP");
for (i = 0; i < 30; i++) {
char name[4];
snprintf(name, sizeof(name), "X%u", i);
show_data(regs->regs[i] - nbytes, nbytes * 2, name);
}
set_fs(fs);
}
void __show_regs(struct pt_regs *regs)
{
int i, top_reg;
u64 lr, sp;
if (compat_user_mode(regs)) {
lr = regs->compat_lr;
sp = regs->compat_sp;
top_reg = 12;
} else {
lr = regs->regs[30];
sp = regs->sp;
top_reg = 29;
}
show_regs_print_info(KERN_DEFAULT);
print_symbol("PC is at %s\n", instruction_pointer(regs));
print_symbol("LR is at %s\n", lr);
printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
regs->pc, lr, regs->pstate);
printk("sp : %016llx\n", sp);
for (i = top_reg; i >= 0; i--) {
printk("x%-2d: %016llx ", i, regs->regs[i]);
if (i % 2 == 0)
printk("\n");
}
if (!user_mode(regs))
show_extra_register_data(regs, 128);
printk("\n");
}
void show_regs(struct pt_regs * regs)
{
printk("\n");
__show_regs(regs);
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
}
static void tls_thread_flush(void)
{
asm ("msr tpidr_el0, xzr");
if (is_compat_task()) {
current->thread.tp_value = 0;
/*
* We need to ensure ordering between the shadow state and the
* hardware state, so that we don't corrupt the hardware state
* with a stale shadow state during context switch.
*/
barrier();
asm ("msr tpidrro_el0, xzr");
}
}
void flush_thread(void)
{
fpsimd_flush_thread();
tls_thread_flush();
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_preserve_current_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 *childregs = task_pt_regs(p);
unsigned long tls = p->thread.tp_value;
memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
if (likely(!(p->flags & PF_KTHREAD))) {
*childregs = *current_pt_regs();
childregs->regs[0] = 0;
if (is_compat_thread(task_thread_info(p))) {
if (stack_start)
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));
if (stack_start) {
/* 16-byte aligned stack mandatory on AArch64 */
if (stack_start & 15)
return -EINVAL;
childregs->sp = stack_start;
}
}
/*
* If a TLS pointer was passed to clone (4th argument), use it
* for the new thread.
*/
if (clone_flags & CLONE_SETTLS)
tls = childregs->regs[3];
} else {
memset(childregs, 0, sizeof(struct pt_regs));
childregs->pstate = PSR_MODE_EL1h;
p->thread.cpu_context.x19 = stack_start;
p->thread.cpu_context.x20 = stk_sz;
}
p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
p->thread.cpu_context.sp = (unsigned long)childregs;
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);
contextidr_thread_switch(next);
/*
* Complete any pending TLB or cache maintenance on this CPU in case
* the thread migrates to a different CPU.
*/
dsb(ish);
/* the actual thread switch */
last = cpu_switch_to(prev, next);
return last;
}
unsigned long get_wchan(struct task_struct *p)
{
struct stackframe frame;
unsigned long stack_page;
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);
stack_page = (unsigned long)task_stack_page(p);
do {
if (frame.sp < stack_page ||
frame.sp >= stack_page + THREAD_SIZE ||
unwind_frame(&frame))
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);
}