linux/arch/arm/kernel/process.c
Thomas Gleixner 448eca9093 arm: Remove unused cpu_idle_wait()
cpuidle uses a generic function now. Remove the unused code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Link: http://lkml.kernel.org/r/20120507175652.260797846@linutronix.de
2012-05-08 12:35:06 +02:00

547 lines
13 KiB
C

/*
* linux/arch/arm/kernel/process.c
*
* Copyright (C) 1996-2000 Russell King - Converted to ARM.
* Original Copyright (C) 1995 Linus Torvalds
*
* 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.
*/
#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/cpuidle.h>
#include <asm/cacheflush.h>
#include <asm/leds.h>
#include <asm/processor.h>
#include <asm/thread_notify.h>
#include <asm/stacktrace.h>
#include <asm/mach/time.h>
#ifdef CONFIG_CC_STACKPROTECTOR
#include <linux/stackprotector.h>
unsigned long __stack_chk_guard __read_mostly;
EXPORT_SYMBOL(__stack_chk_guard);
#endif
static const char *processor_modes[] = {
"USER_26", "FIQ_26" , "IRQ_26" , "SVC_26" , "UK4_26" , "UK5_26" , "UK6_26" , "UK7_26" ,
"UK8_26" , "UK9_26" , "UK10_26", "UK11_26", "UK12_26", "UK13_26", "UK14_26", "UK15_26",
"USER_32", "FIQ_32" , "IRQ_32" , "SVC_32" , "UK4_32" , "UK5_32" , "UK6_32" , "ABT_32" ,
"UK8_32" , "UK9_32" , "UK10_32", "UND_32" , "UK12_32", "UK13_32", "UK14_32", "SYS_32"
};
static const char *isa_modes[] = {
"ARM" , "Thumb" , "Jazelle", "ThumbEE"
};
extern void setup_mm_for_reboot(void);
static volatile int hlt_counter;
void disable_hlt(void)
{
hlt_counter++;
}
EXPORT_SYMBOL(disable_hlt);
void enable_hlt(void)
{
hlt_counter--;
}
EXPORT_SYMBOL(enable_hlt);
static int __init nohlt_setup(char *__unused)
{
hlt_counter = 1;
return 1;
}
static int __init hlt_setup(char *__unused)
{
hlt_counter = 0;
return 1;
}
__setup("nohlt", nohlt_setup);
__setup("hlt", hlt_setup);
extern void call_with_stack(void (*fn)(void *), void *arg, void *sp);
typedef void (*phys_reset_t)(unsigned long);
/*
* A temporary stack to use for CPU reset. This is static so that we
* don't clobber it with the identity mapping. When running with this
* stack, any references to the current task *will not work* so you
* should really do as little as possible before jumping to your reset
* code.
*/
static u64 soft_restart_stack[16];
static void __soft_restart(void *addr)
{
phys_reset_t phys_reset;
/* Take out a flat memory mapping. */
setup_mm_for_reboot();
/* Clean and invalidate caches */
flush_cache_all();
/* Turn off caching */
cpu_proc_fin();
/* Push out any further dirty data, and ensure cache is empty */
flush_cache_all();
/* Switch to the identity mapping. */
phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset);
phys_reset((unsigned long)addr);
/* Should never get here. */
BUG();
}
void soft_restart(unsigned long addr)
{
u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack);
/* Disable interrupts first */
local_irq_disable();
local_fiq_disable();
/* Disable the L2 if we're the last man standing. */
if (num_online_cpus() == 1)
outer_disable();
/* Change to the new stack and continue with the reset. */
call_with_stack(__soft_restart, (void *)addr, (void *)stack);
/* Should never get here. */
BUG();
}
static void null_restart(char mode, const char *cmd)
{
}
/*
* Function pointers to optional machine specific functions
*/
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
void (*arm_pm_restart)(char str, const char *cmd) = null_restart;
EXPORT_SYMBOL_GPL(arm_pm_restart);
/*
* This is our default idle handler.
*/
void (*arm_pm_idle)(void);
static void default_idle(void)
{
if (arm_pm_idle)
arm_pm_idle();
else
cpu_do_idle();
local_irq_enable();
}
void (*pm_idle)(void) = default_idle;
EXPORT_SYMBOL(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();
leds_event(led_idle_start);
while (!need_resched()) {
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_is_offline(smp_processor_id()))
cpu_die();
#endif
/*
* We need to disable interrupts here
* to ensure we don't miss a wakeup call.
*/
local_irq_disable();
#ifdef CONFIG_PL310_ERRATA_769419
wmb();
#endif
if (hlt_counter) {
local_irq_enable();
cpu_relax();
} else if (!need_resched()) {
stop_critical_timings();
if (cpuidle_idle_call())
pm_idle();
start_critical_timings();
/*
* pm_idle functions must always
* return with IRQs enabled.
*/
WARN_ON(irqs_disabled());
} else
local_irq_enable();
}
leds_event(led_idle_end);
rcu_idle_exit();
tick_nohz_idle_exit();
schedule_preempt_disabled();
}
}
static char reboot_mode = 'h';
int __init reboot_setup(char *str)
{
reboot_mode = str[0];
return 1;
}
__setup("reboot=", reboot_setup);
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();
arm_pm_restart(reboot_mode, cmd);
/* Give a grace period for failure to restart of 1s */
mdelay(1000);
/* Whoops - the platform was unable to reboot. Tell the user! */
printk("Reboot failed -- System halted\n");
while (1);
}
void __show_regs(struct pt_regs *regs)
{
unsigned long flags;
char buf[64];
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->ARM_lr);
printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n"
"sp : %08lx ip : %08lx fp : %08lx\n",
regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr,
regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
regs->ARM_r10, regs->ARM_r9,
regs->ARM_r8);
printk("r7 : %08lx r6 : %08lx r5 : %08lx r4 : %08lx\n",
regs->ARM_r7, regs->ARM_r6,
regs->ARM_r5, regs->ARM_r4);
printk("r3 : %08lx r2 : %08lx r1 : %08lx r0 : %08lx\n",
regs->ARM_r3, regs->ARM_r2,
regs->ARM_r1, regs->ARM_r0);
flags = regs->ARM_cpsr;
buf[0] = flags & PSR_N_BIT ? 'N' : 'n';
buf[1] = flags & PSR_Z_BIT ? 'Z' : 'z';
buf[2] = flags & PSR_C_BIT ? 'C' : 'c';
buf[3] = flags & PSR_V_BIT ? 'V' : 'v';
buf[4] = '\0';
printk("Flags: %s IRQs o%s FIQs o%s Mode %s ISA %s Segment %s\n",
buf, interrupts_enabled(regs) ? "n" : "ff",
fast_interrupts_enabled(regs) ? "n" : "ff",
processor_modes[processor_mode(regs)],
isa_modes[isa_mode(regs)],
get_fs() == get_ds() ? "kernel" : "user");
#ifdef CONFIG_CPU_CP15
{
unsigned int ctrl;
buf[0] = '\0';
#ifdef CONFIG_CPU_CP15_MMU
{
unsigned int transbase, dac;
asm("mrc p15, 0, %0, c2, c0\n\t"
"mrc p15, 0, %1, c3, c0\n"
: "=r" (transbase), "=r" (dac));
snprintf(buf, sizeof(buf), " Table: %08x DAC: %08x",
transbase, dac);
}
#endif
asm("mrc p15, 0, %0, c1, c0\n" : "=r" (ctrl));
printk("Control: %08x%s\n", ctrl, buf);
}
#endif
}
void show_regs(struct pt_regs * regs)
{
printk("\n");
printk("Pid: %d, comm: %20s\n", task_pid_nr(current), current->comm);
__show_regs(regs);
dump_stack();
}
ATOMIC_NOTIFIER_HEAD(thread_notify_head);
EXPORT_SYMBOL_GPL(thread_notify_head);
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
thread_notify(THREAD_NOTIFY_EXIT, current_thread_info());
}
void flush_thread(void)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = current;
flush_ptrace_hw_breakpoint(tsk);
memset(thread->used_cp, 0, sizeof(thread->used_cp));
memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
memset(&thread->fpstate, 0, sizeof(union fp_state));
thread_notify(THREAD_NOTIFY_FLUSH, thread);
}
void release_thread(struct task_struct *dead_task)
{
}
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 thread_info *thread = task_thread_info(p);
struct pt_regs *childregs = task_pt_regs(p);
*childregs = *regs;
childregs->ARM_r0 = 0;
childregs->ARM_sp = stack_start;
memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
thread->cpu_context.sp = (unsigned long)childregs;
thread->cpu_context.pc = (unsigned long)ret_from_fork;
clear_ptrace_hw_breakpoint(p);
if (clone_flags & CLONE_SETTLS)
thread->tp_value = regs->ARM_r3;
thread_notify(THREAD_NOTIFY_COPY, thread);
return 0;
}
/*
* Fill in the task's elfregs structure for a core dump.
*/
int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs)
{
elf_core_copy_regs(elfregs, task_pt_regs(t));
return 1;
}
/*
* fill in the fpe structure for a core dump...
*/
int dump_fpu (struct pt_regs *regs, struct user_fp *fp)
{
struct thread_info *thread = current_thread_info();
int used_math = thread->used_cp[1] | thread->used_cp[2];
if (used_math)
memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
return used_math != 0;
}
EXPORT_SYMBOL(dump_fpu);
/*
* Shuffle the argument into the correct register before calling the
* thread function. r4 is the thread argument, r5 is the pointer to
* the thread function, and r6 points to the exit function.
*/
extern void kernel_thread_helper(void);
asm( ".pushsection .text\n"
" .align\n"
" .type kernel_thread_helper, #function\n"
"kernel_thread_helper:\n"
#ifdef CONFIG_TRACE_IRQFLAGS
" bl trace_hardirqs_on\n"
#endif
" msr cpsr_c, r7\n"
" mov r0, r4\n"
" mov lr, r6\n"
" mov pc, r5\n"
" .size kernel_thread_helper, . - kernel_thread_helper\n"
" .popsection");
#ifdef CONFIG_ARM_UNWIND
extern void kernel_thread_exit(long code);
asm( ".pushsection .text\n"
" .align\n"
" .type kernel_thread_exit, #function\n"
"kernel_thread_exit:\n"
" .fnstart\n"
" .cantunwind\n"
" bl do_exit\n"
" nop\n"
" .fnend\n"
" .size kernel_thread_exit, . - kernel_thread_exit\n"
" .popsection");
#else
#define kernel_thread_exit do_exit
#endif
/*
* Create a kernel thread.
*/
pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
struct pt_regs regs;
memset(&regs, 0, sizeof(regs));
regs.ARM_r4 = (unsigned long)arg;
regs.ARM_r5 = (unsigned long)fn;
regs.ARM_r6 = (unsigned long)kernel_thread_exit;
regs.ARM_r7 = SVC_MODE | PSR_ENDSTATE | PSR_ISETSTATE;
regs.ARM_pc = (unsigned long)kernel_thread_helper;
regs.ARM_cpsr = regs.ARM_r7 | PSR_I_BIT;
return do_fork(flags|CLONE_VM|CLONE_UNTRACED, 0, &regs, 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.lr = 0; /* recovered from the stack */
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_randomize_brk(struct mm_struct *mm)
{
unsigned long range_end = mm->brk + 0x02000000;
return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
}
#ifdef CONFIG_MMU
/*
* The vectors page is always readable from user space for the
* atomic helpers and the signal restart code. Insert it into the
* gate_vma so that it is visible through ptrace and /proc/<pid>/mem.
*/
static struct vm_area_struct gate_vma;
static int __init gate_vma_init(void)
{
gate_vma.vm_start = 0xffff0000;
gate_vma.vm_end = 0xffff0000 + PAGE_SIZE;
gate_vma.vm_page_prot = PAGE_READONLY_EXEC;
gate_vma.vm_flags = VM_READ | VM_EXEC |
VM_MAYREAD | VM_MAYEXEC;
return 0;
}
arch_initcall(gate_vma_init);
struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
return &gate_vma;
}
int in_gate_area(struct mm_struct *mm, unsigned long addr)
{
return (addr >= gate_vma.vm_start) && (addr < gate_vma.vm_end);
}
int in_gate_area_no_mm(unsigned long addr)
{
return in_gate_area(NULL, addr);
}
const char *arch_vma_name(struct vm_area_struct *vma)
{
return (vma == &gate_vma) ? "[vectors]" : NULL;
}
#endif