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/*
* arch/s390/mm/fault.c
*
* S390 version
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Hartmut Penner (hp@de.ibm.com)
*
* Derived from "arch/i386/mm/fault.c"
* Copyright (C) 1995 Linus Torvalds
*/
#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/smp.h>
#include <linux/smp_lock.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/hardirq.h>
extern void die(const char *,struct pt_regs *,long);
/*
* This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate
* routines.
*
* error_code:
* ****0004 Protection -> Write-Protection (suprression)
* ****0010 Segment translation -> Not present (nullification)
* ****0011 Page translation -> Not present (nullification)
*/
asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code)
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
unsigned long address;
unsigned long fixup;
int write;
unsigned long psw_mask;
unsigned long psw_addr;
/*
* get psw mask of Program old psw to find out,
* if user or kernel mode
*/
psw_mask = S390_lowcore.program_old_psw.mask;
psw_addr = S390_lowcore.program_old_psw.addr;
/*
* get the failing address
* more specific the segment and page table portion of
* the address
*/
address = S390_lowcore.trans_exc_code&0x7ffff000;
if (in_irq())
die("page fault from irq handler",regs,error_code);
tsk = current;
mm = tsk->mm;
down(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma) {
printk("no vma for address %lX\n",address);
goto bad_area;
}
if (vma->vm_start <= address)
goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN)) {
printk("VM_GROWSDOWN not set, but address %lX \n",address);
printk("not in vma %p (start %lX end %lX)\n",vma,
vma->vm_start,vma->vm_end);
goto bad_area;
}
if (expand_stack(vma, address)) {
printk("expand of vma failed address %lX\n",address);
printk("vma %p (start %lX end %lX)\n",vma,
vma->vm_start,vma->vm_end);
goto bad_area;
}
/*
* Ok, we have a good vm_area for this memory access, so
* we can handle it..
*/
good_area:
write = 0;
switch (error_code & 0xFF) {
case 0x04: /* write, present*/
write = 1;
break;
case 0x10: /* not present*/
case 0x11: /* not present*/
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) {
printk("flags %X of vma for address %lX wrong \n",
vma->vm_flags,address);
printk("vma %p (start %lX end %lX)\n",vma,
vma->vm_start,vma->vm_end);
goto bad_area;
}
break;
default:
printk("code should be 4, 10 or 11 (%lX) \n",error_code&0xFF);
goto bad_area;
}
handle_mm_fault(tsk, vma, address, write);
up(&mm->mmap_sem);
return;
/*
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
bad_area:
up(&mm->mmap_sem);
/* User mode accesses just cause a SIGSEGV */
if (psw_mask & PSW_PROBLEM_STATE) {
tsk->thread.prot_addr = address;
tsk->thread.error_code = error_code;
tsk->thread.trap_no = 14;
printk("User process fault: interruption code 0x%lX\n",error_code);
printk("failing address: %lX\n",address);
show_crashed_task_info();
force_sig(SIGSEGV, tsk);
return;
}
/* Are we prepared to handle this kernel fault? */
if ((fixup = search_exception_table(regs->psw.addr)) != 0) {
regs->psw.addr = fixup;
return;
}
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
*
* First we check if it was the bootup rw-test, though..
*/
if (address < PAGE_SIZE)
printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
else
printk(KERN_ALERT "Unable to handle kernel paging request");
printk(" at virtual address %08lx\n",address);
/*
* need to define, which information is useful here
*/
lock_kernel();
die("Oops", regs, error_code);
do_exit(SIGKILL);
unlock_kernel();
}
/*
{
char c;
int i,j;
char *addr;
addr = ((char*) psw_addr)-0x20;
for (i=0;i<16;i++) {
if (i == 2)
printk("\n");
printk ("%08X: ",(unsigned long) addr);
for (j=0;j<4;j++) {
printk("%08X ",*(unsigned long*)addr);
addr += 4;
}
addr -=0x10;
printk(" | ");
for (j=0;j<16;j++) {
printk("%c",(c=*addr++) < 0x20 ? '.' : c );
}
printk("\n");
}
printk("\n");
}
*/
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