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linux/arch/ppc/kernel/process.c

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/*
* arch/ppc/kernel/process.c
*
* Derived from "arch/i386/kernel/process.c"
* Copyright (C) 1995 Linus Torvalds
*
* Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
* Paul Mackerras (paulus@cs.anu.edu.au)
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/init.h>
#include <linux/prctl.h>
#include <linux/init_task.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/mqueue.h>
#include <linux/hardirq.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/prom.h>
extern unsigned long _get_SP(void);
struct task_struct *last_task_used_math = NULL;
struct task_struct *last_task_used_altivec = NULL;
struct task_struct *last_task_used_spe = NULL;
static struct fs_struct init_fs = INIT_FS;
static struct files_struct init_files = INIT_FILES;
static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
struct mm_struct init_mm = INIT_MM(init_mm);
EXPORT_SYMBOL(init_mm);
/* this is 8kB-aligned so we can get to the thread_info struct
at the base of it from the stack pointer with 1 integer instruction. */
union thread_union init_thread_union
__attribute__((__section__(".data.init_task"))) =
{ INIT_THREAD_INFO(init_task) };
/* initial task structure */
struct task_struct init_task = INIT_TASK(init_task);
EXPORT_SYMBOL(init_task);
/* only used to get secondary processor up */
struct task_struct *current_set[NR_CPUS] = {&init_task, };
#undef SHOW_TASK_SWITCHES
#undef CHECK_STACK
#if defined(CHECK_STACK)
unsigned long
kernel_stack_top(struct task_struct *tsk)
{
return ((unsigned long)tsk) + sizeof(union task_union);
}
unsigned long
task_top(struct task_struct *tsk)
{
return ((unsigned long)tsk) + sizeof(struct thread_info);
}
/* check to make sure the kernel stack is healthy */
int check_stack(struct task_struct *tsk)
{
unsigned long stack_top = kernel_stack_top(tsk);
unsigned long tsk_top = task_top(tsk);
int ret = 0;
#if 0
/* check thread magic */
if ( tsk->thread.magic != THREAD_MAGIC )
{
ret |= 1;
printk("thread.magic bad: %08x\n", tsk->thread.magic);
}
#endif
if ( !tsk )
printk("check_stack(): tsk bad tsk %p\n",tsk);
/* check if stored ksp is bad */
if ( (tsk->thread.ksp > stack_top) || (tsk->thread.ksp < tsk_top) )
{
printk("stack out of bounds: %s/%d\n"
" tsk_top %08lx ksp %08lx stack_top %08lx\n",
tsk->comm,tsk->pid,
tsk_top, tsk->thread.ksp, stack_top);
ret |= 2;
}
/* check if stack ptr RIGHT NOW is bad */
if ( (tsk == current) && ((_get_SP() > stack_top ) || (_get_SP() < tsk_top)) )
{
printk("current stack ptr out of bounds: %s/%d\n"
" tsk_top %08lx sp %08lx stack_top %08lx\n",
current->comm,current->pid,
tsk_top, _get_SP(), stack_top);
ret |= 4;
}
#if 0
/* check amount of free stack */
for ( i = (unsigned long *)task_top(tsk) ; i < kernel_stack_top(tsk) ; i++ )
{
if ( !i )
printk("check_stack(): i = %p\n", i);
if ( *i != 0 )
{
/* only notify if it's less than 900 bytes */
if ( (i - (unsigned long *)task_top(tsk)) < 900 )
printk("%d bytes free on stack\n",
i - task_top(tsk));
break;
}
}
#endif
if (ret)
{
panic("bad kernel stack");
}
return(ret);
}
#endif /* defined(CHECK_STACK) */
#ifdef CONFIG_ALTIVEC
int
dump_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
{
if (regs->msr & MSR_VEC)
giveup_altivec(current);
memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
return 1;
}
void
enable_kernel_altivec(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
giveup_altivec(current);
else
giveup_altivec(NULL); /* just enable AltiVec for kernel - force */
#else
giveup_altivec(last_task_used_altivec);
#endif /* __SMP __ */
}
EXPORT_SYMBOL(enable_kernel_altivec);
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
int
dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
{
if (regs->msr & MSR_SPE)
giveup_spe(current);
/* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
return 1;
}
void
enable_kernel_spe(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
giveup_spe(current);
else
giveup_spe(NULL); /* just enable SPE for kernel - force */
#else
giveup_spe(last_task_used_spe);
#endif /* __SMP __ */
}
EXPORT_SYMBOL(enable_kernel_spe);
#endif /* CONFIG_SPE */
void
enable_kernel_fp(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
giveup_fpu(current);
else
giveup_fpu(NULL); /* just enables FP for kernel */
#else
giveup_fpu(last_task_used_math);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_fp);
int
dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
{
preempt_disable();
if (tsk->thread.regs && (tsk->thread.regs->msr & MSR_FP))
giveup_fpu(tsk);
preempt_enable();
memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
return 1;
}
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
{
struct thread_struct *new_thread, *old_thread;
unsigned long s;
struct task_struct *last;
local_irq_save(s);
#ifdef CHECK_STACK
check_stack(prev);
check_stack(new);
#endif
#ifdef CONFIG_SMP
/* avoid complexity of lazy save/restore of fpu
* by just saving it every time we switch out if
* this task used the fpu during the last quantum.
*
* If it tries to use the fpu again, it'll trap and
* reload its fp regs. So we don't have to do a restore
* every switch, just a save.
* -- Cort
*/
if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
giveup_fpu(prev);
#ifdef CONFIG_ALTIVEC
/*
* If the previous thread used altivec in the last quantum
* (thus changing altivec regs) then save them.
* We used to check the VRSAVE register but not all apps
* set it, so we don't rely on it now (and in fact we need
* to save & restore VSCR even if VRSAVE == 0). -- paulus
*
* On SMP we always save/restore altivec regs just to avoid the
* complexity of changing processors.
* -- Cort
*/
if ((prev->thread.regs && (prev->thread.regs->msr & MSR_VEC)))
giveup_altivec(prev);
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
/*
* If the previous thread used spe in the last quantum
* (thus changing spe regs) then save them.
*
* On SMP we always save/restore spe regs just to avoid the
* complexity of changing processors.
*/
if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
giveup_spe(prev);
#endif /* CONFIG_SPE */
#endif /* CONFIG_SMP */
/* Avoid the trap. On smp this this never happens since
* we don't set last_task_used_altivec -- Cort
*/
if (new->thread.regs && last_task_used_altivec == new)
new->thread.regs->msr |= MSR_VEC;
#ifdef CONFIG_SPE
/* Avoid the trap. On smp this this never happens since
* we don't set last_task_used_spe
*/
if (new->thread.regs && last_task_used_spe == new)
new->thread.regs->msr |= MSR_SPE;
#endif /* CONFIG_SPE */
new_thread = &new->thread;
old_thread = &current->thread;
last = _switch(old_thread, new_thread);
local_irq_restore(s);
return last;
}
void show_regs(struct pt_regs * regs)
{
int i, trap;
printk("NIP: %08lX LR: %08lX SP: %08lX REGS: %p TRAP: %04lx %s\n",
regs->nip, regs->link, regs->gpr[1], regs, regs->trap,
print_tainted());
printk("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n",
regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0,
regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0,
regs->msr&MSR_IR ? 1 : 0,
regs->msr&MSR_DR ? 1 : 0);
trap = TRAP(regs);
if (trap == 0x300 || trap == 0x600)
printk("DAR: %08lX, DSISR: %08lX\n", regs->dar, regs->dsisr);
printk("TASK = %p[%d] '%s' THREAD: %p\n",
current, current->pid, current->comm, current->thread_info);
printk("Last syscall: %ld ", current->thread.last_syscall);
#ifdef CONFIG_SMP
printk(" CPU: %d", smp_processor_id());
#endif /* CONFIG_SMP */
for (i = 0; i < 32; i++) {
long r;
if ((i % 8) == 0)
printk("\n" KERN_INFO "GPR%02d: ", i);
if (__get_user(r, &regs->gpr[i]))
break;
printk("%08lX ", r);
if (i == 12 && !FULL_REGS(regs))
break;
}
printk("\n");
#ifdef CONFIG_KALLSYMS
/*
* Lookup NIP late so we have the best change of getting the
* above info out without failing
*/
printk("NIP [%08lx] ", regs->nip);
print_symbol("%s\n", regs->nip);
printk("LR [%08lx] ", regs->link);
print_symbol("%s\n", regs->link);
#endif
show_stack(current, (unsigned long *) regs->gpr[1]);
}
void exit_thread(void)
{
if (last_task_used_math == current)
last_task_used_math = NULL;
if (last_task_used_altivec == current)
last_task_used_altivec = NULL;
#ifdef CONFIG_SPE
if (last_task_used_spe == current)
last_task_used_spe = NULL;
#endif
}
void flush_thread(void)
{
if (last_task_used_math == current)
last_task_used_math = NULL;
if (last_task_used_altivec == current)
last_task_used_altivec = NULL;
#ifdef CONFIG_SPE
if (last_task_used_spe == current)
last_task_used_spe = NULL;
#endif
}
void
release_thread(struct task_struct *t)
{
}
/*
* This gets called before we allocate a new thread and copy
* the current task into it.
*/
void prepare_to_copy(struct task_struct *tsk)
{
struct pt_regs *regs = tsk->thread.regs;
if (regs == NULL)
return;
preempt_disable();
if (regs->msr & MSR_FP)
giveup_fpu(current);
#ifdef CONFIG_ALTIVEC
if (regs->msr & MSR_VEC)
giveup_altivec(current);
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
if (regs->msr & MSR_SPE)
giveup_spe(current);
#endif /* CONFIG_SPE */
preempt_enable();
}
/*
* Copy a thread..
*/
int
copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
unsigned long unused,
struct task_struct *p, struct pt_regs *regs)
{
struct pt_regs *childregs, *kregs;
extern void ret_from_fork(void);
unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
unsigned long childframe;
CHECK_FULL_REGS(regs);
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
*childregs = *regs;
if ((childregs->msr & MSR_PR) == 0) {
/* for kernel thread, set `current' and stackptr in new task */
childregs->gpr[1] = sp + sizeof(struct pt_regs);
childregs->gpr[2] = (unsigned long) p;
p->thread.regs = NULL; /* no user register state */
} else {
childregs->gpr[1] = usp;
p->thread.regs = childregs;
if (clone_flags & CLONE_SETTLS)
childregs->gpr[2] = childregs->gpr[6];
}
childregs->gpr[3] = 0; /* Result from fork() */
sp -= STACK_FRAME_OVERHEAD;
childframe = sp;
/*
* The way this works is that at some point in the future
* some task will call _switch to switch to the new task.
* That will pop off the stack frame created below and start
* the new task running at ret_from_fork. The new task will
* do some house keeping and then return from the fork or clone
* system call, using the stack frame created above.
*/
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *) sp;
sp -= STACK_FRAME_OVERHEAD;
p->thread.ksp = sp;
kregs->nip = (unsigned long)ret_from_fork;
p->thread.last_syscall = -1;
return 0;
}
/*
* Set up a thread for executing a new program
*/
void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp)
{
set_fs(USER_DS);
memset(regs->gpr, 0, sizeof(regs->gpr));
regs->ctr = 0;
regs->link = 0;
regs->xer = 0;
regs->ccr = 0;
regs->mq = 0;
regs->nip = nip;
regs->gpr[1] = sp;
regs->msr = MSR_USER;
if (last_task_used_math == current)
last_task_used_math = NULL;
if (last_task_used_altivec == current)
last_task_used_altivec = NULL;
#ifdef CONFIG_SPE
if (last_task_used_spe == current)
last_task_used_spe = NULL;
#endif
memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
current->thread.fpscr = 0;
#ifdef CONFIG_ALTIVEC
memset(current->thread.vr, 0, sizeof(current->thread.vr));
memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
current->thread.vrsave = 0;
current->thread.used_vr = 0;
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
memset(current->thread.evr, 0, sizeof(current->thread.evr));
current->thread.acc = 0;
current->thread.spefscr = 0;
current->thread.used_spe = 0;
#endif /* CONFIG_SPE */
}
#define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
| PR_FP_EXC_RES | PR_FP_EXC_INV)
int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
{
struct pt_regs *regs = tsk->thread.regs;
/* This is a bit hairy. If we are an SPE enabled processor
* (have embedded fp) we store the IEEE exception enable flags in
* fpexc_mode. fpexc_mode is also used for setting FP exception
* mode (asyn, precise, disabled) for 'Classic' FP. */
if (val & PR_FP_EXC_SW_ENABLE) {
#ifdef CONFIG_SPE
tsk->thread.fpexc_mode = val &
(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
#else
return -EINVAL;
#endif
} else {
/* on a CONFIG_SPE this does not hurt us. The bits that
* __pack_fe01 use do not overlap with bits used for
* PR_FP_EXC_SW_ENABLE. Additionally, the MSR[FE0,FE1] bits
* on CONFIG_SPE implementations are reserved so writing to
* them does not change anything */
if (val > PR_FP_EXC_PRECISE)
return -EINVAL;
tsk->thread.fpexc_mode = __pack_fe01(val);
if (regs != NULL && (regs->msr & MSR_FP) != 0)
regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
| tsk->thread.fpexc_mode;
}
return 0;
}
int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
{
unsigned int val;
if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
#ifdef CONFIG_SPE
val = tsk->thread.fpexc_mode;
#else
return -EINVAL;
#endif
else
val = __unpack_fe01(tsk->thread.fpexc_mode);
return put_user(val, (unsigned int __user *) adr);
}
int sys_clone(unsigned long clone_flags, unsigned long usp,
int __user *parent_tidp, void __user *child_threadptr,
int __user *child_tidp, int p6,
struct pt_regs *regs)
{
CHECK_FULL_REGS(regs);
if (usp == 0)
usp = regs->gpr[1]; /* stack pointer for child */
return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
}
int sys_fork(int p1, int p2, int p3, int p4, int p5, int p6,
struct pt_regs *regs)
{
CHECK_FULL_REGS(regs);
return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
}
int sys_vfork(int p1, int p2, int p3, int p4, int p5, int p6,
struct pt_regs *regs)
{
CHECK_FULL_REGS(regs);
return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
regs, 0, NULL, NULL);
}
int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
unsigned long a3, unsigned long a4, unsigned long a5,
struct pt_regs *regs)
{
int error;
char * filename;
filename = getname((char __user *) a0);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
preempt_disable();
if (regs->msr & MSR_FP)
giveup_fpu(current);
#ifdef CONFIG_ALTIVEC
if (regs->msr & MSR_VEC)
giveup_altivec(current);
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
if (regs->msr & MSR_SPE)
giveup_spe(current);
#endif /* CONFIG_SPE */
preempt_enable();
error = do_execve(filename, (char __user *__user *) a1,
(char __user *__user *) a2, regs);
if (error == 0) {
task_lock(current);
current->ptrace &= ~PT_DTRACE;
task_unlock(current);
}
putname(filename);
out:
return error;
}
void dump_stack(void)
{
show_stack(current, NULL);
}
EXPORT_SYMBOL(dump_stack);
void show_stack(struct task_struct *tsk, unsigned long *stack)
{
unsigned long sp, stack_top, prev_sp, ret;
int count = 0;
unsigned long next_exc = 0;
struct pt_regs *regs;
extern char ret_from_except, ret_from_except_full, ret_from_syscall;
sp = (unsigned long) stack;
if (tsk == NULL)
tsk = current;
if (sp == 0) {
if (tsk == current)
asm("mr %0,1" : "=r" (sp));
else
sp = tsk->thread.ksp;
}
prev_sp = (unsigned long) (tsk->thread_info + 1);
stack_top = (unsigned long) tsk->thread_info + THREAD_SIZE;
while (count < 16 && sp > prev_sp && sp < stack_top && (sp & 3) == 0) {
if (count == 0) {
printk("Call trace:");
#ifdef CONFIG_KALLSYMS
printk("\n");
#endif
} else {
if (next_exc) {
ret = next_exc;
next_exc = 0;
} else
ret = *(unsigned long *)(sp + 4);
printk(" [%08lx] ", ret);
#ifdef CONFIG_KALLSYMS
print_symbol("%s", ret);
printk("\n");
#endif
if (ret == (unsigned long) &ret_from_except
|| ret == (unsigned long) &ret_from_except_full
|| ret == (unsigned long) &ret_from_syscall) {
/* sp + 16 points to an exception frame */
regs = (struct pt_regs *) (sp + 16);
if (sp + 16 + sizeof(*regs) <= stack_top)
next_exc = regs->nip;
}
}
++count;
sp = *(unsigned long *)sp;
}
#ifndef CONFIG_KALLSYMS
if (count > 0)
printk("\n");
#endif
}
#if 0
/*
* Low level print for debugging - Cort
*/
int __init ll_printk(const char *fmt, ...)
{
va_list args;
char buf[256];
int i;
va_start(args, fmt);
i=vsprintf(buf,fmt,args);
ll_puts(buf);
va_end(args);
return i;
}
int lines = 24, cols = 80;
int orig_x = 0, orig_y = 0;
void puthex(unsigned long val)
{
unsigned char buf[10];
int i;
for (i = 7; i >= 0; i--)
{
buf[i] = "0123456789ABCDEF"[val & 0x0F];
val >>= 4;
}
buf[8] = '\0';
prom_print(buf);
}
void __init ll_puts(const char *s)
{
int x,y;
char *vidmem = (char *)/*(_ISA_MEM_BASE + 0xB8000) */0xD00B8000;
char c;
extern int mem_init_done;
if ( mem_init_done ) /* assume this means we can printk */
{
printk(s);
return;
}
#if 0
if ( have_of )
{
prom_print(s);
return;
}
#endif
/*
* can't ll_puts on chrp without openfirmware yet.
* vidmem just needs to be setup for it.
* -- Cort
*/
if ( _machine != _MACH_prep )
return;
x = orig_x;
y = orig_y;
while ( ( c = *s++ ) != '\0' ) {
if ( c == '\n' ) {
x = 0;
if ( ++y >= lines ) {
/*scroll();*/
/*y--;*/
y = 0;
}
} else {
vidmem [ ( x + cols * y ) * 2 ] = c;
if ( ++x >= cols ) {
x = 0;
if ( ++y >= lines ) {
/*scroll();*/
/*y--;*/
y = 0;
}
}
}
}
orig_x = x;
orig_y = y;
}
#endif
unsigned long get_wchan(struct task_struct *p)
{
unsigned long ip, sp;
unsigned long stack_page = (unsigned long) p->thread_info;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
sp = p->thread.ksp;
do {
sp = *(unsigned long *)sp;
if (sp < stack_page || sp >= stack_page + 8188)
return 0;
if (count > 0) {
ip = *(unsigned long *)(sp + 4);
if (!in_sched_functions(ip))
return ip;
}
} while (count++ < 16);
return 0;
}
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