/*
* BK Id: SCCS/s.fault.c 1.15 09/24/01 16:35:10 paulus
*/
/*
* 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/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>
#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
extern void (*debugger)(struct pt_regs *);
extern void (*debugger_fault_handler)(struct pt_regs *);
extern int (*debugger_dabr_match)(struct pt_regs *);
int debugger_kernel_faults = 1;
#endif
unsigned long htab_reloads; /* updated by hashtable.S:hash_page() */
unsigned long htab_evicts; /* updated by hashtable.S:hash_page() */
unsigned long htab_preloads; /* updated by hashtable.S:add_hash_page() */
unsigned long pte_misses; /* updated by do_page_fault() */
unsigned long pte_errors; /* updated by do_page_fault() */
unsigned int probingmem;
extern void die_if_kernel(char *, struct pt_regs *, long);
void bad_page_fault(struct pt_regs *, unsigned long, int sig);
void do_page_fault(struct pt_regs *, unsigned long, unsigned long);
/*
* For 600- and 800-family processors, the error_code parameter is DSISR
* for a data fault, SRR1 for an instruction fault. For 400-family processors
* the error_code parameter is ESR for a data fault, 0 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;
siginfo_t info;
int code = SEGV_MAPERR;
#if defined(CONFIG_4xx)
int is_write = error_code & ESR_DST;
#else
int is_write = 0;
/*
* Fortunately the bit assignments in SRR1 for an instruction
* fault and DSISR for a data fault are mostly the same for the
* bits we are interested in. But there are some bits which
* indicate errors in DSISR but can validly be set in SRR1.
*/
if (regs->trap == 0x400)
error_code &= 0x48200000;
else
is_write = error_code & 0x02000000;
#endif /* CONFIG_4xx */
#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
if (debugger_fault_handler && regs->trap == 0x300) {
debugger_fault_handler(regs);
return;
}
#if !defined(CONFIG_4xx)
if (error_code & 0x00400000) {
/* DABR match */
if (debugger_dabr_match(regs))
return;
}
#endif /* !CONFIG_4xx */
#endif /* CONFIG_XMON || CONFIG_KGDB */
if (in_interrupt() || mm == NULL) {
bad_page_fault(regs, address, SIGSEGV);
return;
}
down_read(&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:
code = SEGV_ACCERR;
#if defined(CONFIG_6xx)
if (error_code & 0x95700000)
/* an error such as lwarx to I/O controller space,
address matching DABR, eciwx, etc. */
goto bad_area;
#endif /* CONFIG_6xx */
#if defined(CONFIG_8xx)
/* The MPC8xx seems to always set 0x80000000, which is
* "undefined". Of those that can be set, this is the only
* one which seems bad.
*/
if (error_code & 0x10000000)
/* Guarded storage error. */
goto bad_area;
#endif /* CONFIG_8xx */
/* a write */
if (is_write) {
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;
}
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
* the fault.
*/
survive:
switch (handle_mm_fault(mm, vma, address, is_write)) {
case 1:
current->min_flt++;
break;
case 2:
current->maj_flt++;
break;
case 0:
goto do_sigbus;
default:
goto out_of_memory;
}
up_read(&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_read(&mm->mmap_sem);
pte_errors++;
/* User mode accesses cause a SIGSEGV */
if (user_mode(regs)) {
info.si_signo = SIGSEGV;
info.si_errno = 0;
info.si_code = code;
info.si_addr = (void *) address;
force_sig_info(SIGSEGV, &info, current);
return;
}
bad_page_fault(regs, address, SIGSEGV);
return;
/*
* We ran out of memory, or some other thing happened to us that made
* us unable to handle the page fault gracefully.
*/
out_of_memory:
up_read(&mm->mmap_sem);
if (current->pid == 1) {
current->policy |= SCHED_YIELD;
schedule();
down_read(&mm->mmap_sem);
goto survive;
}
printk("VM: killing process %s\n", current->comm);
if (user_mode(regs))
do_exit(SIGKILL);
bad_page_fault(regs, address, SIGKILL);
return;
do_sigbus:
up_read(&mm->mmap_sem);
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRERR;
info.si_addr = (void *)address;
force_sig_info (SIGBUS, &info, current);
if (!user_mode(regs))
bad_page_fault(regs, address, SIGBUS);
}
/*
* bad_page_fault is called when we have a bad access from the kernel.
* It is called from do_page_fault above and from some of the procedures
* in traps.c.
*/
void
bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
{
extern void die(const char *,struct pt_regs *,long);
unsigned long fixup;
/* 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 */
#if defined(CONFIG_XMON) || defined(CONFIG_KGDB)
if (debugger_kernel_faults)
debugger(regs);
#endif
die("kernel access of bad area", regs, sig);
}
#ifdef CONFIG_8xx
/* The pgtable.h claims some functions generically exist, but I
* can't find them......
*/
pte_t *va_to_pte(unsigned long address)
{
pgd_t *dir;
pmd_t *pmd;
pte_t *pte;
struct mm_struct *mm;
if (address < TASK_SIZE)
mm = current->mm;
else
mm = &init_mm;
dir = pgd_offset(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);
}
}
else {
return (0);
}
}
else {
return (0);
}
return (0);
}
unsigned long va_to_phys(unsigned long address)
{
pte_t *pte;
pte = va_to_pte(address);
if (pte)
return(((unsigned long)(pte_val(*pte)) & PAGE_MASK) | (address & ~(PAGE_MASK)));
return (0);
}
void
print_8xx_pte(struct mm_struct *mm, unsigned long addr)
{
pgd_t * pgd;
pmd_t * pmd;
pte_t * pte;
printk(" pte @ 0x%8lx: ", addr);
pgd = pgd_offset(mm, addr & PAGE_MASK);
if (pgd) {
pmd = pmd_offset(pgd, addr & PAGE_MASK);
if (pmd && pmd_present(*pmd)) {
pte = pte_offset(pmd, addr & PAGE_MASK);
if (pte) {
printk(" (0x%08lx)->(0x%08lx)->0x%08lx\n",
(long)pgd, (long)pte, (long)pte_val(*pte));
#define pp ((long)pte_val(*pte))
printk(" RPN: %05lx PP: %lx SPS: %lx SH: %lx "
"CI: %lx v: %lx\n",
pp>>12, /* rpn */
(pp>>10)&3, /* pp */
(pp>>3)&1, /* small */
(pp>>2)&1, /* shared */
(pp>>1)&1, /* cache inhibit */
pp&1 /* valid */
);
#undef pp
}
else {
printk("no pte\n");
}
}
else {
printk("no pmd\n");
}
}
else {
printk("no pgd\n");
}
}
int
get_8xx_pte(struct mm_struct *mm, unsigned long addr)
{
pgd_t * pgd;
pmd_t * pmd;
pte_t * pte;
int retval = 0;
pgd = pgd_offset(mm, addr & PAGE_MASK);
if (pgd) {
pmd = pmd_offset(pgd, addr & PAGE_MASK);
if (pmd && pmd_present(*pmd)) {
pte = pte_offset(pmd, addr & PAGE_MASK);
if (pte) {
retval = (int)pte_val(*pte);
}
}
}
return(retval);
}
#endif /* CONFIG_8xx */