344 lines
8.7 KiB
C
344 lines
8.7 KiB
C
|
/*
|
||
|
|
* 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.
|
||
|
|
*
|
||
|
|
* Copyright (C) 1995 - 2000 by Ralf Baechle
|
||
|
|
*/
|
||
|
|
#include <linux/context_tracking.h>
|
||
|
|
#include <linux/signal.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/interrupt.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/errno.h>
|
||
|
|
#include <linux/string.h>
|
||
|
|
#include <linux/types.h>
|
||
|
|
#include <linux/ptrace.h>
|
||
|
|
#include <linux/ratelimit.h>
|
||
|
|
#include <linux/mman.h>
|
||
|
|
#include <linux/mm.h>
|
||
|
|
#include <linux/smp.h>
|
||
|
|
#include <linux/kprobes.h>
|
||
|
|
#include <linux/perf_event.h>
|
||
|
|
#include <linux/uaccess.h>
|
||
|
|
|
||
|
|
#include <asm/branch.h>
|
||
|
|
#include <asm/mmu_context.h>
|
||
|
|
#include <asm/ptrace.h>
|
||
|
|
#include <asm/highmem.h> /* For VMALLOC_END */
|
||
|
|
#include <linux/kdebug.h>
|
||
|
|
|
||
|
|
int show_unhandled_signals = 1;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This routine handles page faults. It determines the address,
|
||
|
|
* and the problem, and then passes it off to one of the appropriate
|
||
|
|
* routines.
|
||
|
|
*/
|
||
|
|
static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write,
|
||
|
|
unsigned long address)
|
||
|
|
{
|
||
|
|
struct vm_area_struct * vma = NULL;
|
||
|
|
struct task_struct *tsk = current;
|
||
|
|
struct mm_struct *mm = tsk->mm;
|
||
|
|
const int field = sizeof(unsigned long) * 2;
|
||
|
|
siginfo_t info;
|
||
|
|
int fault;
|
||
|
|
unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
|
||
|
|
|
||
|
|
static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 10);
|
||
|
|
|
||
|
|
#if 0
|
||
|
|
printk("Cpu%d[%s:%d:%0*lx:%ld:%0*lx]\n", raw_smp_processor_id(),
|
||
|
|
current->comm, current->pid, field, address, write,
|
||
|
|
field, regs->cp0_epc);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#ifdef CONFIG_KPROBES
|
||
|
|
/*
|
||
|
|
* This is to notify the fault handler of the kprobes.
|
||
|
|
*/
|
||
|
|
if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
|
||
|
|
current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
|
||
|
|
return;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
info.si_code = SEGV_MAPERR;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
#ifdef CONFIG_64BIT
|
||
|
|
# define VMALLOC_FAULT_TARGET no_context
|
||
|
|
#else
|
||
|
|
# define VMALLOC_FAULT_TARGET vmalloc_fault
|
||
|
|
#endif
|
||
|
|
|
||
|
|
if (unlikely(address >= VMALLOC_START && address <= VMALLOC_END))
|
||
|
|
goto VMALLOC_FAULT_TARGET;
|
||
|
|
#ifdef MODULE_START
|
||
|
|
if (unlikely(address >= MODULE_START && address < MODULE_END))
|
||
|
|
goto VMALLOC_FAULT_TARGET;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If we're in an interrupt or have no user
|
||
|
|
* context, we must not take the fault..
|
||
|
|
*/
|
||
|
|
if (faulthandler_disabled() || !mm)
|
||
|
|
goto bad_area_nosemaphore;
|
||
|
|
|
||
|
|
if (user_mode(regs))
|
||
|
|
flags |= FAULT_FLAG_USER;
|
||
|
|
retry:
|
||
|
|
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;
|
||
|
|
/*
|
||
|
|
* Ok, we have a good vm_area for this memory access, so
|
||
|
|
* we can handle it..
|
||
|
|
*/
|
||
|
|
good_area:
|
||
|
|
info.si_code = SEGV_ACCERR;
|
||
|
|
|
||
|
|
if (write) {
|
||
|
|
if (!(vma->vm_flags & VM_WRITE))
|
||
|
|
goto bad_area;
|
||
|
|
flags |= FAULT_FLAG_WRITE;
|
||
|
|
} else {
|
||
|
|
if (cpu_has_rixi) {
|
||
|
|
if (address == regs->cp0_epc && !(vma->vm_flags & VM_EXEC)) {
|
||
|
|
#if 0
|
||
|
|
pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] XI violation\n",
|
||
|
|
raw_smp_processor_id(),
|
||
|
|
current->comm, current->pid,
|
||
|
|
field, address, write,
|
||
|
|
field, regs->cp0_epc);
|
||
|
|
#endif
|
||
|
|
goto bad_area;
|
||
|
|
}
|
||
|
|
if (!(vma->vm_flags & VM_READ) &&
|
||
|
|
exception_epc(regs) != address) {
|
||
|
|
#if 0
|
||
|
|
pr_notice("Cpu%d[%s:%d:%0*lx:%ld:%0*lx] RI violation\n",
|
||
|
|
raw_smp_processor_id(),
|
||
|
|
current->comm, current->pid,
|
||
|
|
field, address, write,
|
||
|
|
field, regs->cp0_epc);
|
||
|
|
#endif
|
||
|
|
goto bad_area;
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
if (!(vma->vm_flags & (VM_READ | VM_WRITE | 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.
|
||
|
|
*/
|
||
|
|
fault = handle_mm_fault(vma, address, flags);
|
||
|
|
|
||
|
|
if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
|
||
|
|
return;
|
||
|
|
|
||
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
|
||
|
|
if (unlikely(fault & VM_FAULT_ERROR)) {
|
||
|
|
if (fault & VM_FAULT_OOM)
|
||
|
|
goto out_of_memory;
|
||
|
|
else if (fault & VM_FAULT_SIGSEGV)
|
||
|
|
goto bad_area;
|
||
|
|
else if (fault & VM_FAULT_SIGBUS)
|
||
|
|
goto do_sigbus;
|
||
|
|
BUG();
|
||
|
|
}
|
||
|
|
if (flags & FAULT_FLAG_ALLOW_RETRY) {
|
||
|
|
if (fault & VM_FAULT_MAJOR) {
|
||
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MAJ, 1,
|
||
|
|
regs, address);
|
||
|
|
tsk->maj_flt++;
|
||
|
|
} else {
|
||
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS_MIN, 1,
|
||
|
|
regs, address);
|
||
|
|
tsk->min_flt++;
|
||
|
|
}
|
||
|
|
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);
|
||
|
|
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_read(&mm->mmap_sem);
|
||
|
|
|
||
|
|
bad_area_nosemaphore:
|
||
|
|
/* User mode accesses just cause a SIGSEGV */
|
||
|
|
if (user_mode(regs)) {
|
||
|
|
tsk->thread.cp0_badvaddr = address;
|
||
|
|
tsk->thread.error_code = write;
|
||
|
|
if (show_unhandled_signals &&
|
||
|
|
unhandled_signal(tsk, SIGSEGV) &&
|
||
|
|
__ratelimit(&ratelimit_state)) {
|
||
|
|
pr_info("do_page_fault(): sending SIGSEGV to %s for invalid %s %0*lx\n",
|
||
|
|
tsk->comm,
|
||
|
|
write ? "write access to" : "read access from",
|
||
|
|
field, address);
|
||
|
|
pr_info("epc = %0*lx in", field,
|
||
|
|
(unsigned long) regs->cp0_epc);
|
||
|
|
print_vma_addr(KERN_CONT " ", regs->cp0_epc);
|
||
|
|
pr_cont("\n");
|
||
|
|
pr_info("ra = %0*lx in", field,
|
||
|
|
(unsigned long) regs->regs[31]);
|
||
|
|
print_vma_addr(KERN_CONT " ", regs->regs[31]);
|
||
|
|
pr_cont("\n");
|
||
|
|
}
|
||
|
|
current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
|
||
|
|
info.si_signo = SIGSEGV;
|
||
|
|
info.si_errno = 0;
|
||
|
|
/* info.si_code has been set above */
|
||
|
|
info.si_addr = (void __user *) address;
|
||
|
|
force_sig_info(SIGSEGV, &info, tsk);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
no_context:
|
||
|
|
/* Are we prepared to handle this kernel fault? */
|
||
|
|
if (fixup_exception(regs)) {
|
||
|
|
current->thread.cp0_baduaddr = address;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Oops. The kernel tried to access some bad page. We'll have to
|
||
|
|
* terminate things with extreme prejudice.
|
||
|
|
*/
|
||
|
|
bust_spinlocks(1);
|
||
|
|
|
||
|
|
printk(KERN_ALERT "CPU %d Unable to handle kernel paging request at "
|
||
|
|
"virtual address %0*lx, epc == %0*lx, ra == %0*lx\n",
|
||
|
|
raw_smp_processor_id(), field, address, field, regs->cp0_epc,
|
||
|
|
field, regs->regs[31]);
|
||
|
|
die("Oops", regs);
|
||
|
|
|
||
|
|
out_of_memory:
|
||
|
|
/*
|
||
|
|
* 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).
|
||
|
|
*/
|
||
|
|
up_read(&mm->mmap_sem);
|
||
|
|
if (!user_mode(regs))
|
||
|
|
goto no_context;
|
||
|
|
pagefault_out_of_memory();
|
||
|
|
return;
|
||
|
|
|
||
|
|
do_sigbus:
|
||
|
|
up_read(&mm->mmap_sem);
|
||
|
|
|
||
|
|
/* Kernel mode? Handle exceptions or die */
|
||
|
|
if (!user_mode(regs))
|
||
|
|
goto no_context;
|
||
|
|
else
|
||
|
|
/*
|
||
|
|
* Send a sigbus, regardless of whether we were in kernel
|
||
|
|
* or user mode.
|
||
|
|
*/
|
||
|
|
#if 0
|
||
|
|
printk("do_page_fault() #3: sending SIGBUS to %s for "
|
||
|
|
"invalid %s\n%0*lx (epc == %0*lx, ra == %0*lx)\n",
|
||
|
|
tsk->comm,
|
||
|
|
write ? "write access to" : "read access from",
|
||
|
|
field, address,
|
||
|
|
field, (unsigned long) regs->cp0_epc,
|
||
|
|
field, (unsigned long) regs->regs[31]);
|
||
|
|
#endif
|
||
|
|
current->thread.trap_nr = (regs->cp0_cause >> 2) & 0x1f;
|
||
|
|
tsk->thread.cp0_badvaddr = address;
|
||
|
|
info.si_signo = SIGBUS;
|
||
|
|
info.si_errno = 0;
|
||
|
|
info.si_code = BUS_ADRERR;
|
||
|
|
info.si_addr = (void __user *) address;
|
||
|
|
force_sig_info(SIGBUS, &info, tsk);
|
||
|
|
|
||
|
|
return;
|
||
|
|
#ifndef CONFIG_64BIT
|
||
|
|
vmalloc_fault:
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* Synchronize this task's top level page-table
|
||
|
|
* with the 'reference' page table.
|
||
|
|
*
|
||
|
|
* Do _not_ use "tsk" here. We might be inside
|
||
|
|
* an interrupt in the middle of a task switch..
|
||
|
|
*/
|
||
|
|
int offset = __pgd_offset(address);
|
||
|
|
pgd_t *pgd, *pgd_k;
|
||
|
|
pud_t *pud, *pud_k;
|
||
|
|
pmd_t *pmd, *pmd_k;
|
||
|
|
pte_t *pte_k;
|
||
|
|
|
||
|
|
pgd = (pgd_t *) pgd_current[raw_smp_processor_id()] + offset;
|
||
|
|
pgd_k = init_mm.pgd + offset;
|
||
|
|
|
||
|
|
if (!pgd_present(*pgd_k))
|
||
|
|
goto no_context;
|
||
|
|
set_pgd(pgd, *pgd_k);
|
||
|
|
|
||
|
|
pud = pud_offset(pgd, address);
|
||
|
|
pud_k = pud_offset(pgd_k, address);
|
||
|
|
if (!pud_present(*pud_k))
|
||
|
|
goto no_context;
|
||
|
|
|
||
|
|
pmd = pmd_offset(pud, address);
|
||
|
|
pmd_k = pmd_offset(pud_k, address);
|
||
|
|
if (!pmd_present(*pmd_k))
|
||
|
|
goto no_context;
|
||
|
|
set_pmd(pmd, *pmd_k);
|
||
|
|
|
||
|
|
pte_k = pte_offset_kernel(pmd_k, address);
|
||
|
|
if (!pte_present(*pte_k))
|
||
|
|
goto no_context;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
|
||
|
|
unsigned long write, unsigned long address)
|
||
|
|
{
|
||
|
|
enum ctx_state prev_state;
|
||
|
|
|
||
|
|
prev_state = exception_enter();
|
||
|
|
__do_page_fault(regs, write, address);
|
||
|
|
exception_exit(prev_state);
|
||
|
|
}
|