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/*
* arch/ppc/mm/fault.c
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Derived from "arch/i386/mm/fault.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* 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.h>
#include <asm/mmu_context.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#ifdef CONFIG_XMON
extern void xmon(struct pt_regs *);
extern void (*xmon_fault_handler)(struct pt_regs *);
extern int xmon_dabr_match(struct pt_regs *);
int xmon_kernel_faults = 0;
#endif
unsigned long htab_reloads = 0; /* updated by head.S:hash_page() */
unsigned long htab_evicts = 0; /* updated by head.S:hash_page() */
unsigned long pte_misses = 0; /* updated by do_page_fault() */
unsigned long pte_errors = 0; /* updated by do_page_fault() */
unsigned int probingmem = 0;
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);
/*
* The error_code parameter is DSISR for a data fault, SRR1 for
* an instruction fault.
*/
void do_page_fault(struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
struct vm_area_struct * vma;
struct mm_struct *mm = current->mm;
/*printk("address: %08lx code: %08lx %s%s%s%s%s%s\n",
address,error_code,
(error_code&0x40000000)?"604 tlb&htab miss ":"",
(error_code&0x20000000)?"603 tlbmiss ":"",
(error_code&0x02000000)?"write ":"",
(error_code&0x08000000)?"prot ":"",
(error_code&0x95700000)?"I/O ":"",
(regs->trap == 0x400)?"instr":"data"
);*/
#ifdef CONFIG_XMON
if (xmon_fault_handler && regs->trap == 0x300) {
xmon_fault_handler(regs);
return;
}
if (error_code & 0x00400000) {
/* DABR match */
if (xmon_dabr_match(regs))
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);
#ifdef CONFIG_XMON
if (xmon_kernel_faults)
xmon(regs);
#endif
}
}
if (current == NULL) {
bad_page_fault(regs, address);
return;
}
down(&mm->mmap_sem);
vma = find_vma(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 & 0x95700000)
/* 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);
/*
* keep track of tlb+htab misses that are good addrs but
* just need pte's created via handle_mm_fault()
* -- Cort
*/
pte_misses++;
return;
bad_area:
up(&mm->mmap_sem);
pte_errors++;
bad_page_fault(regs, address);
}
void
bad_page_fault(struct pt_regs *regs, unsigned long address)
{
unsigned long fixup;
#if 0
extern unsigned long video_mem_base;
extern unsigned long video_mem_term;
/*
* Remap video IO areas for buggy X servers.
* The S3 server wants direct access to video memory
* at 0x8000 0000 and 0xc000 0000 on prep systems, but
* we don't allow that AND we remap the io areas so it's not
* even there!
* So, for this task only give a virtual=physical mapping of the
* video mem.
* -- Cort
*/
if ( is_prep && user_mode(regs) )
{
printk("%s/%d: fault on %x\n",
current->comm,current->pid,address);
printk("mapping: %x -> %x\n",
address&PAGE_MASK, address&PAGE_MASK);
map_page(current,address&PAGE_MASK,address&PAGE_MASK,
_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_RW | _PAGE_DIRTY | _PAGE_HWWRITE|_PAGE_NO_CACHE|_PAGE_WRITETHRU);
return;
}
#endif
if (user_mode(regs)) {
force_sig(SIGSEGV, current);
return;
}
/* Are we prepared to handle this fault? */
if ((fixup = search_exception_table(regs->nip)) != 0) {
regs->nip = fixup;
return;
}
/* kernel has accessed a bad area */
show_regs(regs);
print_backtrace( (unsigned long *)regs->gpr[1] );
#ifdef CONFIG_XMON
if (xmon_kernel_faults)
xmon(regs);
#endif
panic("kernel access of bad area pc %lx lr %lx address %lX tsk %s/%d",
regs->nip,regs->link,address,current->comm,current->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);
}
#if 0
/*
* Misc debugging functions. Please leave them here. -- Cort
*/
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 %08lX -> va ???\n",
address);
}
}
#endif
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