android_kernel_xiaomi_sm8350/arch/arm/kernel/process.c
Paul Gortmaker 122214428a [ARM] 3911/2: Simplify alloc_thread_info on ARM
Remove ARM local cache of 4 struct thread_info.
Can cause oops under certain circumstances.

Russell indicated the original optimization was
required on older kernels to avoid thread starvation
on memory fragmentation, but may no longer be
required.  I've updated the patch to 19rc4 and
ensured no <config.h> dain-bramage slipped in this
time (sorry about that).

Original description follows:

I was given some test results which pointed to an
Oops in alloc_thread_info (happened 2x), and after
looking at the code, I see that ARM has its own
local cache of 4 struct thread_info. There wasn't
any clear (to me) synchronization between the
alloc_thread_info and the free_thread_info.

I looked over the other arch, and they all simply
allocate them on an as needed basis, so I simplified
the ARM to do the same, based on the other arch
(e.g. PPC) and the folks doing the testing have
indicated that this fixed the oops.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2006-11-30 15:27:03 +00:00

437 lines
9.7 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/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.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 <asm/leds.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/thread_notify.h>
#include <asm/uaccess.h>
#include <asm/mach/time.h>
extern const char *processor_modes[];
extern void setup_mm_for_reboot(char mode);
static volatile int hlt_counter;
#include <asm/arch/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)
{
/*
* 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);
/*
* 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_idle)(void);
EXPORT_SYMBOL(pm_idle);
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
void (*arm_pm_restart)(char str) = 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 (hlt_counter)
cpu_relax();
else {
local_irq_disable();
if (!need_resched()) {
timer_dyn_reprogram();
arch_idle();
}
local_irq_enable();
}
}
/*
* The idle thread. We try to conserve power, while trying to keep
* overall latency low. The architecture specific idle is passed
* a value to indicate the level of "idleness" of the system.
*/
void cpu_idle(void)
{
local_fiq_enable();
/* endless idle loop with no priority at all */
while (1) {
void (*idle)(void) = pm_idle;
#ifdef CONFIG_HOTPLUG_CPU
if (cpu_is_offline(smp_processor_id())) {
leds_event(led_idle_start);
cpu_die();
}
#endif
if (!idle)
idle = default_idle;
leds_event(led_idle_start);
while (!need_resched())
idle();
leds_event(led_idle_end);
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 * __unused)
{
arm_pm_restart(reboot_mode);
}
void __show_regs(struct pt_regs *regs)
{
unsigned long flags = condition_codes(regs);
printk("CPU: %d\n", smp_processor_id());
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>] %s\n"
"sp : %08lx ip : %08lx fp : %08lx\n",
instruction_pointer(regs),
regs->ARM_lr, print_tainted(), 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);
printk("Flags: %c%c%c%c",
flags & PSR_N_BIT ? 'N' : 'n',
flags & PSR_Z_BIT ? 'Z' : 'z',
flags & PSR_C_BIT ? 'C' : 'c',
flags & PSR_V_BIT ? 'V' : 'v');
printk(" IRQs o%s FIQs o%s Mode %s%s Segment %s\n",
interrupts_enabled(regs) ? "n" : "ff",
fast_interrupts_enabled(regs) ? "n" : "ff",
processor_modes[processor_mode(regs)],
thumb_mode(regs) ? " (T)" : "",
get_fs() == get_ds() ? "kernel" : "user");
#if CONFIG_CPU_CP15
{
unsigned int ctrl;
__asm__ (
" mrc p15, 0, %0, c1, c0\n"
: "=r" (ctrl));
printk("Control: %04X\n", ctrl);
}
#ifdef CONFIG_CPU_CP15_MMU
{
unsigned int transbase, dac;
__asm__ (
" mrc p15, 0, %0, c2, c0\n"
" mrc p15, 0, %1, c3, c0\n"
: "=r" (transbase), "=r" (dac));
printk("Table: %08X DAC: %08X\n",
transbase, dac);
}
#endif
#endif
}
void show_regs(struct pt_regs * regs)
{
printk("\n");
printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
__show_regs(regs);
__backtrace();
}
void show_fpregs(struct user_fp *regs)
{
int i;
for (i = 0; i < 8; i++) {
unsigned long *p;
char type;
p = (unsigned long *)(regs->fpregs + i);
switch (regs->ftype[i]) {
case 1: type = 'f'; break;
case 2: type = 'd'; break;
case 3: type = 'e'; break;
default: type = '?'; break;
}
if (regs->init_flag)
type = '?';
printk(" f%d(%c): %08lx %08lx %08lx%c",
i, type, p[0], p[1], p[2], i & 1 ? '\n' : ' ');
}
printk("FPSR: %08lx FPCR: %08lx\n",
(unsigned long)regs->fpsr,
(unsigned long)regs->fpcr);
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
}
ATOMIC_NOTIFIER_HEAD(thread_notify_head);
EXPORT_SYMBOL_GPL(thread_notify_head);
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)
{
struct thread_info *thread = task_thread_info(dead_task);
thread_notify(THREAD_NOTIFY_RELEASE, thread);
}
asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
int
copy_thread(int nr, 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 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);
/*
* fill in the user structure for a core dump..
*/
void dump_thread(struct pt_regs * regs, struct user * dump)
{
struct task_struct *tsk = current;
dump->magic = CMAGIC;
dump->start_code = tsk->mm->start_code;
dump->start_stack = regs->ARM_sp & ~(PAGE_SIZE - 1);
dump->u_tsize = (tsk->mm->end_code - tsk->mm->start_code) >> PAGE_SHIFT;
dump->u_dsize = (tsk->mm->brk - tsk->mm->start_data + PAGE_SIZE - 1) >> PAGE_SHIFT;
dump->u_ssize = 0;
dump->u_debugreg[0] = tsk->thread.debug.bp[0].address;
dump->u_debugreg[1] = tsk->thread.debug.bp[1].address;
dump->u_debugreg[2] = tsk->thread.debug.bp[0].insn.arm;
dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn.arm;
dump->u_debugreg[4] = tsk->thread.debug.nsaved;
if (dump->start_stack < 0x04000000)
dump->u_ssize = (0x04000000 - dump->start_stack) >> PAGE_SHIFT;
dump->regs = *regs;
dump->u_fpvalid = dump_fpu (regs, &dump->u_fp);
}
EXPORT_SYMBOL(dump_thread);
/*
* Shuffle the argument into the correct register before calling the
* thread function. r1 is the thread argument, r2 is the pointer to
* the thread function, and r3 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 r0, r1\n"
" mov lr, r3\n"
" mov pc, r2\n"
" .size kernel_thread_helper, . - kernel_thread_helper\n"
" .previous");
/*
* 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_r1 = (unsigned long)arg;
regs.ARM_r2 = (unsigned long)fn;
regs.ARM_r3 = (unsigned long)do_exit;
regs.ARM_pc = (unsigned long)kernel_thread_helper;
regs.ARM_cpsr = SVC_MODE;
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)
{
unsigned long fp, lr;
unsigned long stack_start, stack_end;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_start = (unsigned long)end_of_stack(p);
stack_end = (unsigned long)task_stack_page(p) + THREAD_SIZE;
fp = thread_saved_fp(p);
do {
if (fp < stack_start || fp > stack_end)
return 0;
lr = pc_pointer (((unsigned long *)fp)[-1]);
if (!in_sched_functions(lr))
return lr;
fp = *(unsigned long *) (fp - 12);
} while (count ++ < 16);
return 0;
}