Contributors: 21
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Paul Mundt |
1056 |
57.20% |
12 |
27.27% |
| Stuart Menefy |
403 |
21.83% |
4 |
9.09% |
| Mike Rapoport |
111 |
6.01% |
1 |
2.27% |
| Linus Torvalds (pre-git) |
98 |
5.31% |
1 |
2.27% |
| Matt Fleming |
23 |
1.25% |
2 |
4.55% |
| Peter Xu |
22 |
1.19% |
4 |
9.09% |
| Kautuk Consul |
21 |
1.14% |
1 |
2.27% |
| Johannes Weiner |
21 |
1.14% |
1 |
2.27% |
| Geert Uytterhoeven |
20 |
1.08% |
1 |
2.27% |
| Nicholas Piggin |
16 |
0.87% |
1 |
2.27% |
| Linus Torvalds |
16 |
0.87% |
1 |
2.27% |
| Michel Lespinasse |
7 |
0.38% |
3 |
6.82% |
| David Hildenbrand |
5 |
0.27% |
1 |
2.27% |
| Anshuman Khandual |
5 |
0.27% |
2 |
4.55% |
| Ingo Molnar |
5 |
0.27% |
2 |
4.55% |
| Eric W. Biedermann |
4 |
0.22% |
2 |
4.55% |
| Magnus Damm |
3 |
0.16% |
1 |
2.27% |
| Shaohua Li |
3 |
0.16% |
1 |
2.27% |
| David Howells |
3 |
0.16% |
1 |
2.27% |
| David Rientjes |
2 |
0.11% |
1 |
2.27% |
| Souptick Joarder |
2 |
0.11% |
1 |
2.27% |
| Total |
1846 |
|
44 |
|
/*
* 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/sched/signal.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/perf_event.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <asm/io_trapped.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/traps.h>
static void
force_sig_info_fault(int si_signo, int si_code, unsigned long address)
{
force_sig_fault(si_signo, si_code, (void __user *)address);
}
/*
* 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;
}
pr_alert("pgd = %p\n", pgd);
pgd += pgd_index(addr);
pr_alert("[%08lx] *pgd=%0*llx", addr, (u32)(sizeof(*pgd) * 2),
(u64)pgd_val(*pgd));
do {
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
if (pgd_none(*pgd))
break;
if (pgd_bad(*pgd)) {
pr_cont("(bad)");
break;
}
p4d = p4d_offset(pgd, addr);
if (PTRS_PER_P4D != 1)
pr_cont(", *p4d=%0*Lx", (u32)(sizeof(*p4d) * 2),
(u64)p4d_val(*p4d));
if (p4d_none(*p4d))
break;
if (p4d_bad(*p4d)) {
pr_cont("(bad)");
break;
}
pud = pud_offset(p4d, addr);
if (PTRS_PER_PUD != 1)
pr_cont(", *pud=%0*llx", (u32)(sizeof(*pud) * 2),
(u64)pud_val(*pud));
if (pud_none(*pud))
break;
if (pud_bad(*pud)) {
pr_cont("(bad)");
break;
}
pmd = pmd_offset(pud, addr);
if (PTRS_PER_PMD != 1)
pr_cont(", *pmd=%0*llx", (u32)(sizeof(*pmd) * 2),
(u64)pmd_val(*pmd));
if (pmd_none(*pmd))
break;
if (pmd_bad(*pmd)) {
pr_cont("(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);
pr_cont(", *pte=%0*llx", (u32)(sizeof(*pte) * 2),
(u64)pte_val(*pte));
} while (0);
pr_cont("\n");
}
static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
{
unsigned index = pgd_index(address);
pgd_t *pgd_k;
p4d_t *p4d, *p4d_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;
p4d = p4d_offset(pgd, address);
p4d_k = p4d_offset(pgd_k, address);
if (!p4d_present(*p4d_k))
return NULL;
pud = pud_offset(p4d, address);
pud_k = pud_offset(p4d_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;
pr_alert("BUG: unable to handle kernel %s at %08lx\n",
address < PAGE_SIZE ? "NULL pointer dereference"
: "paging request",
address);
pr_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)
{
/* 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);
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..
*/
mmap_read_unlock(mm);
__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;
mmap_read_unlock(mm);
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs))
no_context(regs, error_code, address);
force_sig_info_fault(SIGBUS, BUS_ADRERR, address);
}
static noinline int
mm_fault_error(struct pt_regs *regs, unsigned long error_code,
unsigned long address, vm_fault_t fault)
{
/*
* Pagefault was interrupted by SIGKILL. We have no reason to
* continue pagefault.
*/
if (fault_signal_pending(fault, regs)) {
if (!user_mode(regs))
no_context(regs, error_code, address);
return 1;
}
/* Release mmap_lock first if necessary */
if (!(fault & VM_FAULT_RETRY))
mmap_read_unlock(current->mm);
if (!(fault & VM_FAULT_ERROR))
return 0;
if (fault & VM_FAULT_OOM) {
/* Kernel mode? Handle exceptions or die: */
if (!user_mode(regs)) {
no_context(regs, error_code, address);
return 1;
}
/*
* 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 if (fault & VM_FAULT_SIGSEGV)
bad_area(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_is_accessible(vma)))
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;
vm_fault_t fault;
unsigned int flags = FAULT_FLAG_DEFAULT;
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 (kprobe_page_fault(regs, vec))
return;
bad_area_nosemaphore(regs, error_code, address);
return;
}
if (unlikely(kprobe_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
* with pagefaults disabled then we must not take the fault:
*/
if (unlikely(faulthandler_disabled() || !mm)) {
bad_area_nosemaphore(regs, error_code, address);
return;
}
retry:
mmap_read_lock(mm);
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 (user_mode(regs))
flags |= FAULT_FLAG_USER;
if (error_code & FAULT_CODE_WRITE)
flags |= FAULT_FLAG_WRITE;
/*
* 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(vma, address, flags, regs);
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_RETRY) {
flags |= FAULT_FLAG_TRIED;
/*
* No need to mmap_read_unlock(mm) as we would
* have already released it in __lock_page_or_retry
* in mm/filemap.c.
*/
goto retry;
}
}
mmap_read_unlock(mm);
}