/*
* linux/arch/arm26/kernel/process.c
*
* Copyright (C) 2003 Ian Molton - adapted for ARM26
* Copyright (C) 1996-2000 Russell King - Converted to ARM.
* Origional 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/config.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/init.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/leds.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
extern const char *processor_modes[];
extern void setup_mm_for_reboot(char mode);
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);
/*
* This is our default idle handler. We need to disable
* interrupts here to ensure we don't miss a wakeup call.
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
preempt_disable();
while (1) {
while (!need_resched()) {
local_irq_disable();
if (!need_resched() && !hlt_counter)
local_irq_enable();
}
}
schedule();
}
static char reboot_mode = 'h';
int __init reboot_setup(char *str)
{
reboot_mode = str[0];
return 1;
}
__setup("reboot=", reboot_setup);
/* ARM26 cant do these but we still need to define them. */
void machine_halt(void)
{
}
void machine_power_off(void)
{
}
void machine_restart(char * __unused)
{
/*
* 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(reboot_mode);
/*
* copy branch instruction to reset location and call it
*/
*(unsigned long *)0 = *(unsigned long *)0x03800000;
((void(*)(void))0)();
/*
* Whoops - the architecture was unable to reboot.
* Tell the user! Should never happen...
*/
mdelay(1000);
printk("Reboot failed -- System halted\n");
while (1);
}
void show_regs(struct pt_regs * regs)
{
unsigned long flags;
flags = condition_codes(regs);
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 Segment %s\n",
interrupts_enabled(regs) ? "n" : "ff",
fast_interrupts_enabled(regs) ? "n" : "ff",
processor_modes[processor_mode(regs)],
get_fs() == get_ds() ? "kernel" : "user");
}
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);
}
/*
* Task structure and kernel stack allocation.
*/
static unsigned long *thread_info_head;
static unsigned int nr_thread_info;
extern unsigned long get_page_8k(int priority);
extern void free_page_8k(unsigned long page);
// FIXME - is this valid?
#define EXTRA_TASK_STRUCT 0
#define ll_alloc_task_struct() ((struct thread_info *)get_page_8k(GFP_KERNEL))
#define ll_free_task_struct(p) free_page_8k((unsigned long)(p))
//FIXME - do we use *task param below looks like we dont, which is ok?
//FIXME - if EXTRA_TASK_STRUCT is zero we can optimise the below away permanently. *IF* its supposed to be zero.
struct thread_info *alloc_thread_info(struct task_struct *task)
{
struct thread_info *thread = NULL;
if (EXTRA_TASK_STRUCT) {
unsigned long *p = thread_info_head;
if (p) {
thread_info_head = (unsigned long *)p[0];
nr_thread_info -= 1;
}
thread = (struct thread_info *)p;
}
if (!thread)
thread = ll_alloc_task_struct();
#ifdef CONFIG_MAGIC_SYSRQ
/*
* The stack must be cleared if you want SYSRQ-T to
* give sensible stack usage information
*/
if (thread) {
char *p = (char *)thread;
memzero(p+KERNEL_STACK_SIZE, KERNEL_STACK_SIZE);
}
#endif
return thread;
}
void free_thread_info(struct thread_info *thread)
{
if (EXTRA_TASK_STRUCT && nr_thread_info < EXTRA_TASK_STRUCT) {
unsigned long *p = (unsigned long *)thread;
p[0] = (unsigned long)thread_info_head;
thread_info_head = p;
nr_thread_info += 1;
} else
ll_free_task_struct(thread);
}
/*
* Free current thread data structures etc..
*/
void exit_thread(void)
{
}
void flush_thread(void)
{
struct thread_info *thread = current_thread_info();
struct task_struct *tsk = current;
memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
memset(&thread->fpstate, 0, sizeof(union fp_state));
clear_used_math();
}
void release_thread(struct task_struct *dead_task)
{
}
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 unused, struct task_struct *p, struct pt_regs *regs)
{
struct thread_info *thread = p->thread_info;
struct pt_regs *childregs;
childregs = __get_user_regs(thread);
*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 | MODE_SVC26 | PSR_I_BIT;
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 = !!used_math();
if (used_math)
memcpy(fp, &thread->fpstate.soft, sizeof (*fp));
return used_math;
}
/*
* 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;
dump->u_debugreg[3] = tsk->thread.debug.bp[1].insn;
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);
}
/*
* 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.
* FIXME - make sure this is right - the older code used to zero fp
* and cause the parent to call sys_exit (do_exit in this version)
*/
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(®s, 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 | MODE_SVC26;
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)
{
unsigned long fp, lr;
unsigned long stack_page;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
stack_page = 4096 + (unsigned long)p;
fp = thread_saved_fp(p);
do {
if (fp < stack_page || fp > 4092+stack_page)
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;
}
