463 lines
11 KiB
C
463 lines
11 KiB
C
![]() |
/*
|
||
|
* linux/arch/arm/mm/fault.c
|
||
|
*
|
||
|
* Copyright (C) 1995 Linus Torvalds
|
||
|
* Modifications for ARM processor (c) 1995-2004 Russell King
|
||
|
*
|
||
|
* This program is free software; you can redistribute it and/or modify
|
||
|
* it under the terms of the GNU General Public License version 2 as
|
||
|
* published by the Free Software Foundation.
|
||
|
*/
|
||
|
#include <linux/config.h>
|
||
|
#include <linux/module.h>
|
||
|
#include <linux/signal.h>
|
||
|
#include <linux/ptrace.h>
|
||
|
#include <linux/mm.h>
|
||
|
#include <linux/init.h>
|
||
|
|
||
|
#include <asm/system.h>
|
||
|
#include <asm/pgtable.h>
|
||
|
#include <asm/tlbflush.h>
|
||
|
#include <asm/uaccess.h>
|
||
|
|
||
|
#include "fault.h"
|
||
|
|
||
|
/*
|
||
|
* This is useful to dump out the page tables associated with
|
||
|
* 'addr' in mm 'mm'.
|
||
|
*/
|
||
|
void show_pte(struct mm_struct *mm, unsigned long addr)
|
||
|
{
|
||
|
pgd_t *pgd;
|
||
|
|
||
|
if (!mm)
|
||
|
mm = &init_mm;
|
||
|
|
||
|
printk(KERN_ALERT "pgd = %p\n", mm->pgd);
|
||
|
pgd = pgd_offset(mm, addr);
|
||
|
printk(KERN_ALERT "[%08lx] *pgd=%08lx", addr, pgd_val(*pgd));
|
||
|
|
||
|
do {
|
||
|
pmd_t *pmd;
|
||
|
pte_t *pte;
|
||
|
|
||
|
if (pgd_none(*pgd))
|
||
|
break;
|
||
|
|
||
|
if (pgd_bad(*pgd)) {
|
||
|
printk("(bad)");
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
pmd = pmd_offset(pgd, addr);
|
||
|
#if PTRS_PER_PMD != 1
|
||
|
printk(", *pmd=%08lx", pmd_val(*pmd));
|
||
|
#endif
|
||
|
|
||
|
if (pmd_none(*pmd))
|
||
|
break;
|
||
|
|
||
|
if (pmd_bad(*pmd)) {
|
||
|
printk("(bad)");
|
||
|
break;
|
||
|
}
|
||
|
|
||
|
#ifndef CONFIG_HIGHMEM
|
||
|
/* We must not map this if we have highmem enabled */
|
||
|
pte = pte_offset_map(pmd, addr);
|
||
|
printk(", *pte=%08lx", pte_val(*pte));
|
||
|
printk(", *ppte=%08lx", pte_val(pte[-PTRS_PER_PTE]));
|
||
|
pte_unmap(pte);
|
||
|
#endif
|
||
|
} while(0);
|
||
|
|
||
|
printk("\n");
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Oops. The kernel tried to access some page that wasn't present.
|
||
|
*/
|
||
|
static void
|
||
|
__do_kernel_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
|
||
|
struct pt_regs *regs)
|
||
|
{
|
||
|
/*
|
||
|
* Are we prepared to handle this kernel fault?
|
||
|
*/
|
||
|
if (fixup_exception(regs))
|
||
|
return;
|
||
|
|
||
|
/*
|
||
|
* No handler, we'll have to terminate things with extreme prejudice.
|
||
|
*/
|
||
|
bust_spinlocks(1);
|
||
|
printk(KERN_ALERT
|
||
|
"Unable to handle kernel %s at virtual address %08lx\n",
|
||
|
(addr < PAGE_SIZE) ? "NULL pointer dereference" :
|
||
|
"paging request", addr);
|
||
|
|
||
|
show_pte(mm, addr);
|
||
|
die("Oops", regs, fsr);
|
||
|
bust_spinlocks(0);
|
||
|
do_exit(SIGKILL);
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Something tried to access memory that isn't in our memory map..
|
||
|
* User mode accesses just cause a SIGSEGV
|
||
|
*/
|
||
|
static void
|
||
|
__do_user_fault(struct task_struct *tsk, unsigned long addr,
|
||
|
unsigned int fsr, int code, struct pt_regs *regs)
|
||
|
{
|
||
|
struct siginfo si;
|
||
|
|
||
|
#ifdef CONFIG_DEBUG_USER
|
||
|
if (user_debug & UDBG_SEGV) {
|
||
|
printk(KERN_DEBUG "%s: unhandled page fault at 0x%08lx, code 0x%03x\n",
|
||
|
tsk->comm, addr, fsr);
|
||
|
show_pte(tsk->mm, addr);
|
||
|
show_regs(regs);
|
||
|
}
|
||
|
#endif
|
||
|
|
||
|
tsk->thread.address = addr;
|
||
|
tsk->thread.error_code = fsr;
|
||
|
tsk->thread.trap_no = 14;
|
||
|
si.si_signo = SIGSEGV;
|
||
|
si.si_errno = 0;
|
||
|
si.si_code = code;
|
||
|
si.si_addr = (void __user *)addr;
|
||
|
force_sig_info(SIGSEGV, &si, tsk);
|
||
|
}
|
||
|
|
||
|
void
|
||
|
do_bad_area(struct task_struct *tsk, struct mm_struct *mm, unsigned long addr,
|
||
|
unsigned int fsr, struct pt_regs *regs)
|
||
|
{
|
||
|
/*
|
||
|
* If we are in kernel mode at this point, we
|
||
|
* have no context to handle this fault with.
|
||
|
*/
|
||
|
if (user_mode(regs))
|
||
|
__do_user_fault(tsk, addr, fsr, SEGV_MAPERR, regs);
|
||
|
else
|
||
|
__do_kernel_fault(mm, addr, fsr, regs);
|
||
|
}
|
||
|
|
||
|
#define VM_FAULT_BADMAP (-20)
|
||
|
#define VM_FAULT_BADACCESS (-21)
|
||
|
|
||
|
static int
|
||
|
__do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
|
||
|
struct task_struct *tsk)
|
||
|
{
|
||
|
struct vm_area_struct *vma;
|
||
|
int fault, mask;
|
||
|
|
||
|
vma = find_vma(mm, addr);
|
||
|
fault = VM_FAULT_BADMAP;
|
||
|
if (!vma)
|
||
|
goto out;
|
||
|
if (vma->vm_start > addr)
|
||
|
goto check_stack;
|
||
|
|
||
|
/*
|
||
|
* Ok, we have a good vm_area for this
|
||
|
* memory access, so we can handle it.
|
||
|
*/
|
||
|
good_area:
|
||
|
if (fsr & (1 << 11)) /* write? */
|
||
|
mask = VM_WRITE;
|
||
|
else
|
||
|
mask = VM_READ|VM_EXEC;
|
||
|
|
||
|
fault = VM_FAULT_BADACCESS;
|
||
|
if (!(vma->vm_flags & mask))
|
||
|
goto out;
|
||
|
|
||
|
/*
|
||
|
* If for any reason at all we couldn't handle
|
||
|
* the fault, make sure we exit gracefully rather
|
||
|
* than endlessly redo the fault.
|
||
|
*/
|
||
|
survive:
|
||
|
fault = handle_mm_fault(mm, vma, addr & PAGE_MASK, fsr & (1 << 11));
|
||
|
|
||
|
/*
|
||
|
* Handle the "normal" cases first - successful and sigbus
|
||
|
*/
|
||
|
switch (fault) {
|
||
|
case VM_FAULT_MAJOR:
|
||
|
tsk->maj_flt++;
|
||
|
return fault;
|
||
|
case VM_FAULT_MINOR:
|
||
|
tsk->min_flt++;
|
||
|
case VM_FAULT_SIGBUS:
|
||
|
return fault;
|
||
|
}
|
||
|
|
||
|
if (tsk->pid != 1)
|
||
|
goto out;
|
||
|
|
||
|
/*
|
||
|
* If we are out of memory for pid1,
|
||
|
* sleep for a while and retry
|
||
|
*/
|
||
|
yield();
|
||
|
goto survive;
|
||
|
|
||
|
check_stack:
|
||
|
if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))
|
||
|
goto good_area;
|
||
|
out:
|
||
|
return fault;
|
||
|
}
|
||
|
|
||
|
static int
|
||
|
do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
||
|
{
|
||
|
struct task_struct *tsk;
|
||
|
struct mm_struct *mm;
|
||
|
int fault;
|
||
|
|
||
|
tsk = current;
|
||
|
mm = tsk->mm;
|
||
|
|
||
|
/*
|
||
|
* If we're in an interrupt or have no user
|
||
|
* context, we must not take the fault..
|
||
|
*/
|
||
|
if (in_interrupt() || !mm)
|
||
|
goto no_context;
|
||
|
|
||
|
down_read(&mm->mmap_sem);
|
||
|
fault = __do_page_fault(mm, addr, fsr, tsk);
|
||
|
up_read(&mm->mmap_sem);
|
||
|
|
||
|
/*
|
||
|
* Handle the "normal" case first
|
||
|
*/
|
||
|
if (fault > 0)
|
||
|
return 0;
|
||
|
|
||
|
/*
|
||
|
* We had some memory, but were unable to
|
||
|
* successfully fix up this page fault.
|
||
|
*/
|
||
|
if (fault == 0)
|
||
|
goto do_sigbus;
|
||
|
|
||
|
/*
|
||
|
* If we are in kernel mode at this point, we
|
||
|
* have no context to handle this fault with.
|
||
|
*/
|
||
|
if (!user_mode(regs))
|
||
|
goto no_context;
|
||
|
|
||
|
if (fault == VM_FAULT_OOM) {
|
||
|
/*
|
||
|
* We ran out of memory, or some other thing happened to
|
||
|
* us that made us unable to handle the page fault gracefully.
|
||
|
*/
|
||
|
printk("VM: killing process %s\n", tsk->comm);
|
||
|
do_exit(SIGKILL);
|
||
|
} else
|
||
|
__do_user_fault(tsk, addr, fsr, fault == VM_FAULT_BADACCESS ?
|
||
|
SEGV_ACCERR : SEGV_MAPERR, regs);
|
||
|
return 0;
|
||
|
|
||
|
|
||
|
/*
|
||
|
* We ran out of memory, or some other thing happened to us that made
|
||
|
* us unable to handle the page fault gracefully.
|
||
|
*/
|
||
|
do_sigbus:
|
||
|
/*
|
||
|
* Send a sigbus, regardless of whether we were in kernel
|
||
|
* or user mode.
|
||
|
*/
|
||
|
tsk->thread.address = addr;
|
||
|
tsk->thread.error_code = fsr;
|
||
|
tsk->thread.trap_no = 14;
|
||
|
force_sig(SIGBUS, tsk);
|
||
|
#ifdef CONFIG_DEBUG_USER
|
||
|
if (user_debug & UDBG_BUS) {
|
||
|
printk(KERN_DEBUG "%s: sigbus at 0x%08lx, pc=0x%08lx\n",
|
||
|
current->comm, addr, instruction_pointer(regs));
|
||
|
}
|
||
|
#endif
|
||
|
|
||
|
/* Kernel mode? Handle exceptions or die */
|
||
|
if (user_mode(regs))
|
||
|
return 0;
|
||
|
|
||
|
no_context:
|
||
|
__do_kernel_fault(mm, addr, fsr, regs);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* First Level Translation Fault Handler
|
||
|
*
|
||
|
* We enter here because the first level page table doesn't contain
|
||
|
* a valid entry for the address.
|
||
|
*
|
||
|
* If the address is in kernel space (>= TASK_SIZE), then we are
|
||
|
* probably faulting in the vmalloc() area.
|
||
|
*
|
||
|
* If the init_task's first level page tables contains the relevant
|
||
|
* entry, we copy the it to this task. If not, we send the process
|
||
|
* a signal, fixup the exception, or oops the kernel.
|
||
|
*
|
||
|
* NOTE! We MUST NOT take any locks for this case. We may be in an
|
||
|
* interrupt or a critical region, and should only copy the information
|
||
|
* from the master page table, nothing more.
|
||
|
*/
|
||
|
static int
|
||
|
do_translation_fault(unsigned long addr, unsigned int fsr,
|
||
|
struct pt_regs *regs)
|
||
|
{
|
||
|
struct task_struct *tsk;
|
||
|
unsigned int index;
|
||
|
pgd_t *pgd, *pgd_k;
|
||
|
pmd_t *pmd, *pmd_k;
|
||
|
|
||
|
if (addr < TASK_SIZE)
|
||
|
return do_page_fault(addr, fsr, regs);
|
||
|
|
||
|
index = pgd_index(addr);
|
||
|
|
||
|
/*
|
||
|
* FIXME: CP15 C1 is write only on ARMv3 architectures.
|
||
|
*/
|
||
|
pgd = cpu_get_pgd() + index;
|
||
|
pgd_k = init_mm.pgd + index;
|
||
|
|
||
|
if (pgd_none(*pgd_k))
|
||
|
goto bad_area;
|
||
|
|
||
|
if (!pgd_present(*pgd))
|
||
|
set_pgd(pgd, *pgd_k);
|
||
|
|
||
|
pmd_k = pmd_offset(pgd_k, addr);
|
||
|
pmd = pmd_offset(pgd, addr);
|
||
|
|
||
|
if (pmd_none(*pmd_k))
|
||
|
goto bad_area;
|
||
|
|
||
|
copy_pmd(pmd, pmd_k);
|
||
|
return 0;
|
||
|
|
||
|
bad_area:
|
||
|
tsk = current;
|
||
|
|
||
|
do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Some section permission faults need to be handled gracefully.
|
||
|
* They can happen due to a __{get,put}_user during an oops.
|
||
|
*/
|
||
|
static int
|
||
|
do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
||
|
{
|
||
|
struct task_struct *tsk = current;
|
||
|
do_bad_area(tsk, tsk->active_mm, addr, fsr, regs);
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* This abort handler always returns "fault".
|
||
|
*/
|
||
|
static int
|
||
|
do_bad(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
||
|
{
|
||
|
return 1;
|
||
|
}
|
||
|
|
||
|
static struct fsr_info {
|
||
|
int (*fn)(unsigned long addr, unsigned int fsr, struct pt_regs *regs);
|
||
|
int sig;
|
||
|
const char *name;
|
||
|
} fsr_info[] = {
|
||
|
/*
|
||
|
* The following are the standard ARMv3 and ARMv4 aborts. ARMv5
|
||
|
* defines these to be "precise" aborts.
|
||
|
*/
|
||
|
{ do_bad, SIGSEGV, "vector exception" },
|
||
|
{ do_bad, SIGILL, "alignment exception" },
|
||
|
{ do_bad, SIGKILL, "terminal exception" },
|
||
|
{ do_bad, SIGILL, "alignment exception" },
|
||
|
{ do_bad, SIGBUS, "external abort on linefetch" },
|
||
|
{ do_translation_fault, SIGSEGV, "section translation fault" },
|
||
|
{ do_bad, SIGBUS, "external abort on linefetch" },
|
||
|
{ do_page_fault, SIGSEGV, "page translation fault" },
|
||
|
{ do_bad, SIGBUS, "external abort on non-linefetch" },
|
||
|
{ do_bad, SIGSEGV, "section domain fault" },
|
||
|
{ do_bad, SIGBUS, "external abort on non-linefetch" },
|
||
|
{ do_bad, SIGSEGV, "page domain fault" },
|
||
|
{ do_bad, SIGBUS, "external abort on translation" },
|
||
|
{ do_sect_fault, SIGSEGV, "section permission fault" },
|
||
|
{ do_bad, SIGBUS, "external abort on translation" },
|
||
|
{ do_page_fault, SIGSEGV, "page permission fault" },
|
||
|
/*
|
||
|
* The following are "imprecise" aborts, which are signalled by bit
|
||
|
* 10 of the FSR, and may not be recoverable. These are only
|
||
|
* supported if the CPU abort handler supports bit 10.
|
||
|
*/
|
||
|
{ do_bad, SIGBUS, "unknown 16" },
|
||
|
{ do_bad, SIGBUS, "unknown 17" },
|
||
|
{ do_bad, SIGBUS, "unknown 18" },
|
||
|
{ do_bad, SIGBUS, "unknown 19" },
|
||
|
{ do_bad, SIGBUS, "lock abort" }, /* xscale */
|
||
|
{ do_bad, SIGBUS, "unknown 21" },
|
||
|
{ do_bad, SIGBUS, "imprecise external abort" }, /* xscale */
|
||
|
{ do_bad, SIGBUS, "unknown 23" },
|
||
|
{ do_bad, SIGBUS, "dcache parity error" }, /* xscale */
|
||
|
{ do_bad, SIGBUS, "unknown 25" },
|
||
|
{ do_bad, SIGBUS, "unknown 26" },
|
||
|
{ do_bad, SIGBUS, "unknown 27" },
|
||
|
{ do_bad, SIGBUS, "unknown 28" },
|
||
|
{ do_bad, SIGBUS, "unknown 29" },
|
||
|
{ do_bad, SIGBUS, "unknown 30" },
|
||
|
{ do_bad, SIGBUS, "unknown 31" }
|
||
|
};
|
||
|
|
||
|
void __init
|
||
|
hook_fault_code(int nr, int (*fn)(unsigned long, unsigned int, struct pt_regs *),
|
||
|
int sig, const char *name)
|
||
|
{
|
||
|
if (nr >= 0 && nr < ARRAY_SIZE(fsr_info)) {
|
||
|
fsr_info[nr].fn = fn;
|
||
|
fsr_info[nr].sig = sig;
|
||
|
fsr_info[nr].name = name;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* Dispatch a data abort to the relevant handler.
|
||
|
*/
|
||
|
asmlinkage void
|
||
|
do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
|
||
|
{
|
||
|
const struct fsr_info *inf = fsr_info + (fsr & 15) + ((fsr & (1 << 10)) >> 6);
|
||
|
|
||
|
if (!inf->fn(addr, fsr, regs))
|
||
|
return;
|
||
|
|
||
|
printk(KERN_ALERT "Unhandled fault: %s (0x%03x) at 0x%08lx\n",
|
||
|
inf->name, fsr, addr);
|
||
|
force_sig(inf->sig, current);
|
||
|
show_pte(current->mm, addr);
|
||
|
die_if_kernel("Oops", regs, 0);
|
||
|
}
|
||
|
|
||
|
asmlinkage void
|
||
|
do_PrefetchAbort(unsigned long addr, struct pt_regs *regs)
|
||
|
{
|
||
|
do_translation_fault(addr, 0, regs);
|
||
|
}
|
||
|
|