515 lines
11 KiB
C
515 lines
11 KiB
C
/*
|
|
* Page fault handler for SH with an MMU.
|
|
*
|
|
* Copyright (C) 1999 Niibe Yutaka
|
|
* Copyright (C) 2003 - 2012 Paul Mundt
|
|
*
|
|
* Based on linux/arch/i386/mm/fault.c:
|
|
* Copyright (C) 1995 Linus Torvalds
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/hardirq.h>
|
|
#include <linux/kprobes.h>
|
|
#include <linux/perf_event.h>
|
|
#include <linux/kdebug.h>
|
|
#include <asm/io_trapped.h>
|
|
#include <asm/mmu_context.h>
|
|
#include <asm/tlbflush.h>
|
|
#include <asm/traps.h>
|
|
|
|
static inline int notify_page_fault(struct pt_regs *regs, int trap)
|
|
{
|
|
int ret = 0;
|
|
|
|
if (kprobes_built_in() && !user_mode(regs)) {
|
|
preempt_disable();
|
|
if (kprobe_running() && kprobe_fault_handler(regs, trap))
|
|
ret = 1;
|
|
preempt_enable();
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void
|
|
force_sig_info_fault(int si_signo, int si_code, unsigned long address,
|
|
struct task_struct *tsk)
|
|
{
|
|
siginfo_t info;
|
|
|
|
info.si_signo = si_signo;
|
|
info.si_errno = 0;
|
|
info.si_code = si_code;
|
|
info.si_addr = (void __user *)address;
|
|
|
|
force_sig_info(si_signo, &info, tsk);
|
|
}
|
|
|
|
/*
|
|
* This is useful to dump out the page tables associated with
|
|
* 'addr' in mm 'mm'.
|
|
*/
|
|
static void show_pte(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
pgd_t *pgd;
|
|
|
|
if (mm) {
|
|
pgd = mm->pgd;
|
|
} else {
|
|
pgd = get_TTB();
|
|
|
|
if (unlikely(!pgd))
|
|
pgd = swapper_pg_dir;
|
|
}
|
|
|
|
printk(KERN_ALERT "pgd = %p\n", pgd);
|
|
pgd += pgd_index(addr);
|
|
printk(KERN_ALERT "[%08lx] *pgd=%0*Lx", addr,
|
|
(u32)(sizeof(*pgd) * 2), (u64)pgd_val(*pgd));
|
|
|
|
do {
|
|
pud_t *pud;
|
|
pmd_t *pmd;
|
|
pte_t *pte;
|
|
|
|
if (pgd_none(*pgd))
|
|
break;
|
|
|
|
if (pgd_bad(*pgd)) {
|
|
printk("(bad)");
|
|
break;
|
|
}
|
|
|
|
pud = pud_offset(pgd, addr);
|
|
if (PTRS_PER_PUD != 1)
|
|
printk(", *pud=%0*Lx", (u32)(sizeof(*pud) * 2),
|
|
(u64)pud_val(*pud));
|
|
|
|
if (pud_none(*pud))
|
|
break;
|
|
|
|
if (pud_bad(*pud)) {
|
|
printk("(bad)");
|
|
break;
|
|
}
|
|
|
|
pmd = pmd_offset(pud, addr);
|
|
if (PTRS_PER_PMD != 1)
|
|
printk(", *pmd=%0*Lx", (u32)(sizeof(*pmd) * 2),
|
|
(u64)pmd_val(*pmd));
|
|
|
|
if (pmd_none(*pmd))
|
|
break;
|
|
|
|
if (pmd_bad(*pmd)) {
|
|
printk("(bad)");
|
|
break;
|
|
}
|
|
|
|
/* We must not map this if we have highmem enabled */
|
|
if (PageHighMem(pfn_to_page(pmd_val(*pmd) >> PAGE_SHIFT)))
|
|
break;
|
|
|
|
pte = pte_offset_kernel(pmd, addr);
|
|
printk(", *pte=%0*Lx", (u32)(sizeof(*pte) * 2),
|
|
(u64)pte_val(*pte));
|
|
} while (0);
|
|
|
|
printk("\n");
|
|
}
|
|
|
|
static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
|
|
{
|
|
unsigned index = pgd_index(address);
|
|
pgd_t *pgd_k;
|
|
pud_t *pud, *pud_k;
|
|
pmd_t *pmd, *pmd_k;
|
|
|
|
pgd += index;
|
|
pgd_k = init_mm.pgd + index;
|
|
|
|
if (!pgd_present(*pgd_k))
|
|
return NULL;
|
|
|
|
pud = pud_offset(pgd, address);
|
|
pud_k = pud_offset(pgd_k, address);
|
|
if (!pud_present(*pud_k))
|
|
return NULL;
|
|
|
|
if (!pud_present(*pud))
|
|
set_pud(pud, *pud_k);
|
|
|
|
pmd = pmd_offset(pud, address);
|
|
pmd_k = pmd_offset(pud_k, address);
|
|
if (!pmd_present(*pmd_k))
|
|
return NULL;
|
|
|
|
if (!pmd_present(*pmd))
|
|
set_pmd(pmd, *pmd_k);
|
|
else {
|
|
/*
|
|
* The page tables are fully synchronised so there must
|
|
* be another reason for the fault. Return NULL here to
|
|
* signal that we have not taken care of the fault.
|
|
*/
|
|
BUG_ON(pmd_page(*pmd) != pmd_page(*pmd_k));
|
|
return NULL;
|
|
}
|
|
|
|
return pmd_k;
|
|
}
|
|
|
|
#ifdef CONFIG_SH_STORE_QUEUES
|
|
#define __FAULT_ADDR_LIMIT P3_ADDR_MAX
|
|
#else
|
|
#define __FAULT_ADDR_LIMIT VMALLOC_END
|
|
#endif
|
|
|
|
/*
|
|
* Handle a fault on the vmalloc or module mapping area
|
|
*/
|
|
static noinline int vmalloc_fault(unsigned long address)
|
|
{
|
|
pgd_t *pgd_k;
|
|
pmd_t *pmd_k;
|
|
pte_t *pte_k;
|
|
|
|
/* Make sure we are in vmalloc/module/P3 area: */
|
|
if (!(address >= VMALLOC_START && address < __FAULT_ADDR_LIMIT))
|
|
return -1;
|
|
|
|
/*
|
|
* Synchronize this task's top level page-table
|
|
* with the 'reference' page table.
|
|
*
|
|
* Do _not_ use "current" here. We might be inside
|
|
* an interrupt in the middle of a task switch..
|
|
*/
|
|
pgd_k = get_TTB();
|
|
pmd_k = vmalloc_sync_one(pgd_k, address);
|
|
if (!pmd_k)
|
|
return -1;
|
|
|
|
pte_k = pte_offset_kernel(pmd_k, address);
|
|
if (!pte_present(*pte_k))
|
|
return -1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
show_fault_oops(struct pt_regs *regs, unsigned long address)
|
|
{
|
|
if (!oops_may_print())
|
|
return;
|
|
|
|
printk(KERN_ALERT "BUG: unable to handle kernel ");
|
|
if (address < PAGE_SIZE)
|
|
printk(KERN_CONT "NULL pointer dereference");
|
|
else
|
|
printk(KERN_CONT "paging request");
|
|
|
|
printk(KERN_CONT " at %08lx\n", address);
|
|
printk(KERN_ALERT "PC:");
|
|
printk_address(regs->pc, 1);
|
|
|
|
show_pte(NULL, address);
|
|
}
|
|
|
|
static noinline void
|
|
no_context(struct pt_regs *regs, unsigned long error_code,
|
|
unsigned long address)
|
|
{
|
|
/* Are we prepared to handle this kernel fault? */
|
|
if (fixup_exception(regs))
|
|
return;
|
|
|
|
if (handle_trapped_io(regs, address))
|
|
return;
|
|
|
|
/*
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
|
* terminate things with extreme prejudice.
|
|
*/
|
|
bust_spinlocks(1);
|
|
|
|
show_fault_oops(regs, address);
|
|
|
|
die("Oops", regs, error_code);
|
|
bust_spinlocks(0);
|
|
do_exit(SIGKILL);
|
|
}
|
|
|
|
static void
|
|
__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
|
|
unsigned long address, int si_code)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
/* User mode accesses just cause a SIGSEGV */
|
|
if (user_mode(regs)) {
|
|
/*
|
|
* It's possible to have interrupts off here:
|
|
*/
|
|
local_irq_enable();
|
|
|
|
force_sig_info_fault(SIGSEGV, si_code, address, tsk);
|
|
|
|
return;
|
|
}
|
|
|
|
no_context(regs, error_code, address);
|
|
}
|
|
|
|
static noinline void
|
|
bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
|
|
unsigned long address)
|
|
{
|
|
__bad_area_nosemaphore(regs, error_code, address, SEGV_MAPERR);
|
|
}
|
|
|
|
static void
|
|
__bad_area(struct pt_regs *regs, unsigned long error_code,
|
|
unsigned long address, int si_code)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
|
|
/*
|
|
* Something tried to access memory that isn't in our memory map..
|
|
* Fix it, but check if it's kernel or user first..
|
|
*/
|
|
up_read(&mm->mmap_sem);
|
|
|
|
__bad_area_nosemaphore(regs, error_code, address, si_code);
|
|
}
|
|
|
|
static noinline void
|
|
bad_area(struct pt_regs *regs, unsigned long error_code, unsigned long address)
|
|
{
|
|
__bad_area(regs, error_code, address, SEGV_MAPERR);
|
|
}
|
|
|
|
static noinline void
|
|
bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
|
|
unsigned long address)
|
|
{
|
|
__bad_area(regs, error_code, address, SEGV_ACCERR);
|
|
}
|
|
|
|
static void
|
|
do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
struct mm_struct *mm = tsk->mm;
|
|
|
|
up_read(&mm->mmap_sem);
|
|
|
|
/* Kernel mode? Handle exceptions or die: */
|
|
if (!user_mode(regs))
|
|
no_context(regs, error_code, address);
|
|
|
|
force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
|
|
}
|
|
|
|
static noinline int
|
|
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
|
|
unsigned long address, unsigned int fault)
|
|
{
|
|
/*
|
|
* Pagefault was interrupted by SIGKILL. We have no reason to
|
|
* continue pagefault.
|
|
*/
|
|
if (fatal_signal_pending(current)) {
|
|
if (!(fault & VM_FAULT_RETRY))
|
|
up_read(¤t->mm->mmap_sem);
|
|
if (!user_mode(regs))
|
|
no_context(regs, error_code, address);
|
|
return 1;
|
|
}
|
|
|
|
if (!(fault & VM_FAULT_ERROR))
|
|
return 0;
|
|
|
|
if (fault & VM_FAULT_OOM) {
|
|
/* Kernel mode? Handle exceptions or die: */
|
|
if (!user_mode(regs)) {
|
|
up_read(¤t->mm->mmap_sem);
|
|
no_context(regs, error_code, address);
|
|
return 1;
|
|
}
|
|
up_read(¤t->mm->mmap_sem);
|
|
|
|
/*
|
|
* We ran out of memory, call the OOM killer, and return the
|
|
* userspace (which will retry the fault, or kill us if we got
|
|
* oom-killed):
|
|
*/
|
|
pagefault_out_of_memory();
|
|
} else {
|
|
if (fault & VM_FAULT_SIGBUS)
|
|
do_sigbus(regs, error_code, address);
|
|
else
|
|
BUG();
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static inline int access_error(int error_code, struct vm_area_struct *vma)
|
|
{
|
|
if (error_code & FAULT_CODE_WRITE) {
|
|
/* write, present and write, not present: */
|
|
if (unlikely(!(vma->vm_flags & VM_WRITE)))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/* ITLB miss on NX page */
|
|
if (unlikely((error_code & FAULT_CODE_ITLB) &&
|
|
!(vma->vm_flags & VM_EXEC)))
|
|
return 1;
|
|
|
|
/* read, not present: */
|
|
if (unlikely(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int fault_in_kernel_space(unsigned long address)
|
|
{
|
|
return address >= TASK_SIZE;
|
|
}
|
|
|
|
/*
|
|
* This routine handles page faults. It determines the address,
|
|
* and the problem, and then passes it off to one of the appropriate
|
|
* routines.
|
|
*/
|
|
asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
|
|
unsigned long error_code,
|
|
unsigned long address)
|
|
{
|
|
unsigned long vec;
|
|
struct task_struct *tsk;
|
|
struct mm_struct *mm;
|
|
struct vm_area_struct * vma;
|
|
int fault;
|
|
int write = error_code & FAULT_CODE_WRITE;
|
|
unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
|
|
(write ? FAULT_FLAG_WRITE : 0));
|
|
|
|
tsk = current;
|
|
mm = tsk->mm;
|
|
vec = lookup_exception_vector();
|
|
|
|
/*
|
|
* We fault-in kernel-space virtual memory on-demand. The
|
|
* 'reference' page table is init_mm.pgd.
|
|
*
|
|
* 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.
|
|
*/
|
|
if (unlikely(fault_in_kernel_space(address))) {
|
|
if (vmalloc_fault(address) >= 0)
|
|
return;
|
|
if (notify_page_fault(regs, vec))
|
|
return;
|
|
|
|
bad_area_nosemaphore(regs, error_code, address);
|
|
return;
|
|
}
|
|
|
|
if (unlikely(notify_page_fault(regs, vec)))
|
|
return;
|
|
|
|
/* Only enable interrupts if they were on before the fault */
|
|
if ((regs->sr & SR_IMASK) != SR_IMASK)
|
|
local_irq_enable();
|
|
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
|
|
|
|
/*
|
|
* If we're in an interrupt, have no user context or are running
|
|
* in an atomic region then we must not take the fault:
|
|
*/
|
|
if (unlikely(in_atomic() || !mm)) {
|
|
bad_area_nosemaphore(regs, error_code, address);
|
|
return;
|
|
}
|
|
|
|
retry:
|
|
down_read(&mm->mmap_sem);
|
|
|
|
vma = find_vma(mm, address);
|
|
if (unlikely(!vma)) {
|
|
bad_area(regs, error_code, address);
|
|
return;
|
|
}
|
|
if (likely(vma->vm_start <= address))
|
|
goto good_area;
|
|
if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
|
|
bad_area(regs, error_code, address);
|
|
return;
|
|
}
|
|
if (unlikely(expand_stack(vma, address))) {
|
|
bad_area(regs, error_code, address);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Ok, we have a good vm_area for this memory access, so
|
|
* we can handle it..
|
|
*/
|
|
good_area:
|
|
if (unlikely(access_error(error_code, vma))) {
|
|
bad_area_access_error(regs, error_code, address);
|
|
return;
|
|
}
|
|
|
|
set_thread_fault_code(error_code);
|
|
|
|
/*
|
|
* If for any reason at all we couldn't handle the fault,
|
|
* make sure we exit gracefully rather than endlessly redo
|
|
* the fault.
|
|
*/
|
|
fault = handle_mm_fault(mm, vma, address, flags);
|
|
|
|
if (unlikely(fault & (VM_FAULT_RETRY | VM_FAULT_ERROR)))
|
|
if (mm_fault_error(regs, error_code, address, fault))
|
|
return;
|
|
|
|
if (flags & FAULT_FLAG_ALLOW_RETRY) {
|
|
if (fault & VM_FAULT_MAJOR) {
|
|
tsk->maj_flt++;
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
|
|
regs, address);
|
|
} else {
|
|
tsk->min_flt++;
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
|
|
regs, address);
|
|
}
|
|
if (fault & VM_FAULT_RETRY) {
|
|
flags &= ~FAULT_FLAG_ALLOW_RETRY;
|
|
flags |= FAULT_FLAG_TRIED;
|
|
|
|
/*
|
|
* No need to up_read(&mm->mmap_sem) as we would
|
|
* have already released it in __lock_page_or_retry
|
|
* in mm/filemap.c.
|
|
*/
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
up_read(&mm->mmap_sem);
|
|
}
|