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linux/arch/arm/kernel/process.c

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/*
* 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/module.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 <asm/leds.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/thread_notify.h>
#include <asm/stacktrace.h>
#include <asm/mach/time.h>
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(char mode);
static volatile int hlt_counter;
#include <mach/system.h>
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);
void arm_machine_restart(char mode, const char *cmd)
{
/*
* Clean and disable cache, and turn off interrupts
*/
cpu_proc_fin();
/*
* 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(mode);
/*
* Now call the architecture specific reboot code.
*/
arch_reset(mode, cmd);
/*
* Whoops - the architecture was unable to reboot.
* Tell the user!
*/
mdelay(1000);
printk("Reboot failed -- System halted\n");
while (1);
}
/*
* 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) = arm_machine_restart;
EXPORT_SYMBOL_GPL(arm_pm_restart);
/*
* This is our default idle handler. We need to disable
* interrupts here to ensure we don't miss a wakeup call.
*/
static void default_idle(void)
{
if (!need_resched())
arch_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_stop_sched_tick(1);
leds_event(led_idle_start);
while (!need_resched()) {
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_is_offline(smp_processor_id()))
cpu_die();
#endif
local_irq_disable();
if (hlt_counter) {
local_irq_enable();
cpu_relax();
} else {
stop_critical_timings();
pm_idle();
start_critical_timings();
/*
* This will eventually be removed - pm_idle
* functions should always return with IRQs
* enabled.
*/
WARN_ON(irqs_disabled());
local_irq_enable();
}
}
leds_event(led_idle_end);
tick_nohz_restart_sched_tick();
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
static char reboot_mode = 'h';
int __init reboot_setup(char *str)
{
reboot_mode = str[0];
return 1;
}
__setup("reboot=", reboot_setup);
void machine_halt(void)
{
}
void machine_power_off(void)
{
if (pm_power_off)
pm_power_off();
}
void machine_restart(char *cmd)
{
arm_pm_restart(reboot_mode, cmd);
}
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);
__backtrace();
}
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;
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;
if (clone_flags & CLONE_SETTLS)
thread->tp_value = regs->ARM_r3;
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
ARM: lockdep: fix unannotated irqs-on CPU: Testing write buffer coherency: ok ------------[ cut here ]------------ WARNING: at kernel/lockdep.c:3145 check_flags+0xcc/0x1dc() Modules linked in: [<c0035120>] (unwind_backtrace+0x0/0xf8) from [<c0355374>] (dump_stack+0x20/0x24) [<c0355374>] (dump_stack+0x20/0x24) from [<c0060c04>] (warn_slowpath_common+0x58/0x70) [<c0060c04>] (warn_slowpath_common+0x58/0x70) from [<c0060c3c>] (warn_slowpath_null+0x20/0x24) [<c0060c3c>] (warn_slowpath_null+0x20/0x24) from [<c008f224>] (check_flags+0xcc/0x1dc) [<c008f224>] (check_flags+0xcc/0x1dc) from [<c00945dc>] (lock_acquire+0x50/0x140) [<c00945dc>] (lock_acquire+0x50/0x140) from [<c0358434>] (_raw_spin_lock+0x50/0x88) [<c0358434>] (_raw_spin_lock+0x50/0x88) from [<c00fd114>] (set_task_comm+0x2c/0x60) [<c00fd114>] (set_task_comm+0x2c/0x60) from [<c007e184>] (kthreadd+0x30/0x108) [<c007e184>] (kthreadd+0x30/0x108) from [<c0030104>] (kernel_thread_exit+0x0/0x8) ---[ end trace 1b75b31a2719ed1c ]--- possible reason: unannotated irqs-on. irq event stamp: 3 hardirqs last enabled at (2): [<c0059bb0>] finish_task_switch+0x48/0xb0 hardirqs last disabled at (3): [<c002f0b0>] ret_slow_syscall+0xc/0x1c softirqs last enabled at (0): [<c005f3e0>] copy_process+0x394/0xe5c softirqs last disabled at (0): [<(null)>] (null) Fix this by ensuring that the lockdep interrupt state is manipulated in the appropriate places. We essentially treat userspace as an entirely separate environment which isn't relevant to lockdep (lockdep doesn't monitor userspace.) We don't tell lockdep that IRQs will be enabled in that environment. Instead, when creating kernel threads (which is a rare event compared to entering/leaving userspace) we have to update the lockdep state. Do this by starting threads with IRQs disabled, and in the kthread helper, tell lockdep that IRQs are enabled, and enable them. This provides lockdep with a consistent view of the current IRQ state in kernel space. This also revert portions of 0d928b0b616d1c5c5fe76019a87cba171ca91633 which didn't fix the problem. Tested-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-07-10 02:10:18 -07:00
* 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"
ARM: lockdep: fix unannotated irqs-on CPU: Testing write buffer coherency: ok ------------[ cut here ]------------ WARNING: at kernel/lockdep.c:3145 check_flags+0xcc/0x1dc() Modules linked in: [<c0035120>] (unwind_backtrace+0x0/0xf8) from [<c0355374>] (dump_stack+0x20/0x24) [<c0355374>] (dump_stack+0x20/0x24) from [<c0060c04>] (warn_slowpath_common+0x58/0x70) [<c0060c04>] (warn_slowpath_common+0x58/0x70) from [<c0060c3c>] (warn_slowpath_null+0x20/0x24) [<c0060c3c>] (warn_slowpath_null+0x20/0x24) from [<c008f224>] (check_flags+0xcc/0x1dc) [<c008f224>] (check_flags+0xcc/0x1dc) from [<c00945dc>] (lock_acquire+0x50/0x140) [<c00945dc>] (lock_acquire+0x50/0x140) from [<c0358434>] (_raw_spin_lock+0x50/0x88) [<c0358434>] (_raw_spin_lock+0x50/0x88) from [<c00fd114>] (set_task_comm+0x2c/0x60) [<c00fd114>] (set_task_comm+0x2c/0x60) from [<c007e184>] (kthreadd+0x30/0x108) [<c007e184>] (kthreadd+0x30/0x108) from [<c0030104>] (kernel_thread_exit+0x0/0x8) ---[ end trace 1b75b31a2719ed1c ]--- possible reason: unannotated irqs-on. irq event stamp: 3 hardirqs last enabled at (2): [<c0059bb0>] finish_task_switch+0x48/0xb0 hardirqs last disabled at (3): [<c002f0b0>] ret_slow_syscall+0xc/0x1c softirqs last enabled at (0): [<c005f3e0>] copy_process+0x394/0xe5c softirqs last disabled at (0): [<(null)>] (null) Fix this by ensuring that the lockdep interrupt state is manipulated in the appropriate places. We essentially treat userspace as an entirely separate environment which isn't relevant to lockdep (lockdep doesn't monitor userspace.) We don't tell lockdep that IRQs will be enabled in that environment. Instead, when creating kernel threads (which is a rare event compared to entering/leaving userspace) we have to update the lockdep state. Do this by starting threads with IRQs disabled, and in the kthread helper, tell lockdep that IRQs are enabled, and enable them. This provides lockdep with a consistent view of the current IRQ state in kernel space. This also revert portions of 0d928b0b616d1c5c5fe76019a87cba171ca91633 which didn't fix the problem. Tested-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-07-10 02:10:18 -07:00
#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));
ARM: lockdep: fix unannotated irqs-on CPU: Testing write buffer coherency: ok ------------[ cut here ]------------ WARNING: at kernel/lockdep.c:3145 check_flags+0xcc/0x1dc() Modules linked in: [<c0035120>] (unwind_backtrace+0x0/0xf8) from [<c0355374>] (dump_stack+0x20/0x24) [<c0355374>] (dump_stack+0x20/0x24) from [<c0060c04>] (warn_slowpath_common+0x58/0x70) [<c0060c04>] (warn_slowpath_common+0x58/0x70) from [<c0060c3c>] (warn_slowpath_null+0x20/0x24) [<c0060c3c>] (warn_slowpath_null+0x20/0x24) from [<c008f224>] (check_flags+0xcc/0x1dc) [<c008f224>] (check_flags+0xcc/0x1dc) from [<c00945dc>] (lock_acquire+0x50/0x140) [<c00945dc>] (lock_acquire+0x50/0x140) from [<c0358434>] (_raw_spin_lock+0x50/0x88) [<c0358434>] (_raw_spin_lock+0x50/0x88) from [<c00fd114>] (set_task_comm+0x2c/0x60) [<c00fd114>] (set_task_comm+0x2c/0x60) from [<c007e184>] (kthreadd+0x30/0x108) [<c007e184>] (kthreadd+0x30/0x108) from [<c0030104>] (kernel_thread_exit+0x0/0x8) ---[ end trace 1b75b31a2719ed1c ]--- possible reason: unannotated irqs-on. irq event stamp: 3 hardirqs last enabled at (2): [<c0059bb0>] finish_task_switch+0x48/0xb0 hardirqs last disabled at (3): [<c002f0b0>] ret_slow_syscall+0xc/0x1c softirqs last enabled at (0): [<c005f3e0>] copy_process+0x394/0xe5c softirqs last disabled at (0): [<(null)>] (null) Fix this by ensuring that the lockdep interrupt state is manipulated in the appropriate places. We essentially treat userspace as an entirely separate environment which isn't relevant to lockdep (lockdep doesn't monitor userspace.) We don't tell lockdep that IRQs will be enabled in that environment. Instead, when creating kernel threads (which is a rare event compared to entering/leaving userspace) we have to update the lockdep state. Do this by starting threads with IRQs disabled, and in the kthread helper, tell lockdep that IRQs are enabled, and enable them. This provides lockdep with a consistent view of the current IRQ state in kernel space. This also revert portions of 0d928b0b616d1c5c5fe76019a87cba171ca91633 which didn't fix the problem. Tested-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-07-10 02:10:18 -07:00
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;
ARM: lockdep: fix unannotated irqs-on CPU: Testing write buffer coherency: ok ------------[ cut here ]------------ WARNING: at kernel/lockdep.c:3145 check_flags+0xcc/0x1dc() Modules linked in: [<c0035120>] (unwind_backtrace+0x0/0xf8) from [<c0355374>] (dump_stack+0x20/0x24) [<c0355374>] (dump_stack+0x20/0x24) from [<c0060c04>] (warn_slowpath_common+0x58/0x70) [<c0060c04>] (warn_slowpath_common+0x58/0x70) from [<c0060c3c>] (warn_slowpath_null+0x20/0x24) [<c0060c3c>] (warn_slowpath_null+0x20/0x24) from [<c008f224>] (check_flags+0xcc/0x1dc) [<c008f224>] (check_flags+0xcc/0x1dc) from [<c00945dc>] (lock_acquire+0x50/0x140) [<c00945dc>] (lock_acquire+0x50/0x140) from [<c0358434>] (_raw_spin_lock+0x50/0x88) [<c0358434>] (_raw_spin_lock+0x50/0x88) from [<c00fd114>] (set_task_comm+0x2c/0x60) [<c00fd114>] (set_task_comm+0x2c/0x60) from [<c007e184>] (kthreadd+0x30/0x108) [<c007e184>] (kthreadd+0x30/0x108) from [<c0030104>] (kernel_thread_exit+0x0/0x8) ---[ end trace 1b75b31a2719ed1c ]--- possible reason: unannotated irqs-on. irq event stamp: 3 hardirqs last enabled at (2): [<c0059bb0>] finish_task_switch+0x48/0xb0 hardirqs last disabled at (3): [<c002f0b0>] ret_slow_syscall+0xc/0x1c softirqs last enabled at (0): [<c005f3e0>] copy_process+0x394/0xe5c softirqs last disabled at (0): [<(null)>] (null) Fix this by ensuring that the lockdep interrupt state is manipulated in the appropriate places. We essentially treat userspace as an entirely separate environment which isn't relevant to lockdep (lockdep doesn't monitor userspace.) We don't tell lockdep that IRQs will be enabled in that environment. Instead, when creating kernel threads (which is a rare event compared to entering/leaving userspace) we have to update the lockdep state. Do this by starting threads with IRQs disabled, and in the kthread helper, tell lockdep that IRQs are enabled, and enable them. This provides lockdep with a consistent view of the current IRQ state in kernel space. This also revert portions of 0d928b0b616d1c5c5fe76019a87cba171ca91633 which didn't fix the problem. Tested-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-07-10 02:10:18 -07:00
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;
}