mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
334 lines
8.3 KiB
334 lines
8.3 KiB
/* |
|
* 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; |
|
int si_code; |
|
vm_fault_t fault; |
|
unsigned int flags = FAULT_FLAG_DEFAULT; |
|
|
|
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 |
|
|
|
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; |
|
|
|
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); |
|
retry: |
|
mmap_read_lock(mm); |
|
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: |
|
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 (unlikely(!vma_is_accessible(vma))) |
|
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, regs); |
|
|
|
if (fault_signal_pending(fault, regs)) { |
|
if (!user_mode(regs)) |
|
goto no_context; |
|
return; |
|
} |
|
|
|
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 (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); |
|
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: |
|
mmap_read_unlock(mm); |
|
|
|
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; |
|
force_sig_fault(SIGSEGV, si_code, (void __user *)address); |
|
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). |
|
*/ |
|
mmap_read_unlock(mm); |
|
if (!user_mode(regs)) |
|
goto no_context; |
|
pagefault_out_of_memory(); |
|
return; |
|
|
|
do_sigbus: |
|
mmap_read_unlock(mm); |
|
|
|
/* Kernel mode? Handle exceptions or die */ |
|
if (!user_mode(regs)) |
|
goto no_context; |
|
|
|
/* |
|
* 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; |
|
force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address); |
|
|
|
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_index(address); |
|
pgd_t *pgd, *pgd_k; |
|
p4d_t *p4d, *p4d_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); |
|
|
|
p4d = p4d_offset(pgd, address); |
|
p4d_k = p4d_offset(pgd_k, address); |
|
if (!p4d_present(*p4d_k)) |
|
goto no_context; |
|
|
|
pud = pud_offset(p4d, address); |
|
pud_k = pud_offset(p4d_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); |
|
}
|
|
|