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/*
* arch/ppc/mm/fault.c
*
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
* Ported to PPC by Gary Thomas
* Modified by Cort Dougan and Paul Mackerras.
*
* 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/signal.h>
#include <linux/sched.h>
#include <linux/head.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#ifdef CONFIG_PMAC
extern void (*xmon_fault_handler)(void);
#endif
/* the linux norm for the function name is show_regs() so
make it call dump_regs() on the mac -- Cort */
#ifdef CONFIG_PMAC
#define show_regs dump_regs
#endif
extern void die_if_kernel(char *, struct pt_regs *, long);
void bad_page_fault(struct pt_regs *, unsigned long);
void do_page_fault(struct pt_regs *, unsigned long, unsigned long);
void print_pte(struct _PTE);
void do_page_fault(struct pt_regs *regs, unsigned long address, unsigned long error_code)
{
struct task_struct *tsk = current;
extern unsigned _end[];
struct vm_area_struct * vma;
struct mm_struct *mm = current->mm;
pgd_t *dir;
pmd_t *pmd;
pte_t *pte;
/*printk("do_page_fault() %s/%d addr %x nip %x regs %x error %x\n",
current->comm,current->pid,address,regs->nip,regs,error_code);*/
#ifdef CONFIG_PMAC
if (xmon_fault_handler && regs->trap == 0x300) {
xmon_fault_handler();
return;
}
#endif
if (in_interrupt()) {
static int complained;
if (complained < 20) {
++complained;
printk("page fault in interrupt handler, addr=%lx\n",
address);
show_regs(regs);
}
}
if (current == NULL)
goto bad_area;
do_page:
down(&mm->mmap_sem);
vma = find_vma(tsk->mm, address);
if (!vma)
goto bad_area;
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (expand_stack(vma, address))
goto bad_area;
good_area:
if (error_code & 0xb5700000)
/* an error such as lwarx to I/O controller space,
address matching DABR, eciwx, etc. */
goto bad_area;
/* a write */
if (error_code & 0x02000000) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
/* a read */
} else {
/* protection fault */
if ( error_code & 0x08000000 )
goto bad_area;
if (!(vma->vm_flags & (VM_READ | VM_EXEC)))
goto bad_area;
}
handle_mm_fault(current, vma, address, error_code & 0x02000000);
up(&mm->mmap_sem);
/*printk("do_page_fault() return %s/%d addr %x msr %x\n",
current->comm,current->pid,address,regs->msr);*/
/* not needed since flush_page_to_ram() works */
#if 0
flush_page(address);
#endif
return;
bad_area:
up(¤t->mm->mmap_sem);
bad_page_fault(regs, address);
}
void
bad_page_fault(struct pt_regs *regs, unsigned long address)
{
extern unsigned int probingmem;
struct task_struct *tsk = current;
unsigned long fixup;
/* Are we prepared to handle this fault? */
if ((fixup = search_exception_table(regs->nip)) != 0) {
if ( user_mode(regs) )
printk("Exception from user mode\n");
#if 0
printk(KERN_DEBUG "Exception at %lx (%lx)\n", regs->nip, fixup);
#endif
regs->nip = fixup;
return;
}
if ( user_mode(regs) )
{
force_sig(SIGSEGV, tsk);
return;
}
bad_kernel_access:
/* make sure it's not a bootup probe test */
if ( probingmem )
{
probingmem = 0;
return;
}
/* kernel has accessed a bad area */
show_regs(regs);
print_backtrace( regs->gpr[1] );
#ifdef CONFIG_PMAC
xmon(regs);
#endif
panic("kernel access of bad area\n pc %x address %X tsk %s/%d",
regs->nip,address,tsk->comm,tsk->pid);
}
unsigned long va_to_phys(unsigned long address)
{
pgd_t *dir;
pmd_t *pmd;
pte_t *pte;
dir = pgd_offset(current->mm, address & PAGE_MASK);
if (dir)
{
pmd = pmd_offset(dir, address & PAGE_MASK);
if (pmd && pmd_present(*pmd))
{
pte = pte_offset(pmd, address & PAGE_MASK);
if (pte && pte_present(*pte))
{
return(pte_page(*pte) | (address & ~(PAGE_MASK-1)));
}
} else
{
return (0);
}
} else
{
return (0);
}
return (0);
}
void print_pte(struct _PTE p)
{
printk(
"%08x %08x vsid: %06x h: %01x api: %02x rpn: %05x rcwimg: %d%d%d%d%d%d pp: %02x\n",
*((unsigned long *)(&p)), *((long *)&p+1),
p.vsid, p.h, p.api, p.rpn,
p.r,p.c,p.w,p.i,p.m,p.g,p.pp);
}
/*
* Search the hw hash table for a mapping to the given physical
* address. -- Cort
*/
unsigned long htab_phys_to_va(unsigned long address)
{
extern PTE *Hash, *Hash_end;
PTE *ptr;
for ( ptr = Hash ; ptr < Hash_end ; ptr++ )
{
if ( ptr->rpn == (address>>12) )
printk("phys %08X -> va ???\n",
address);
}
}
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