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Diffstat (limited to 'arch/mips/mm/fault.c')
-rw-r--r--arch/mips/mm/fault.c133
1 files changed, 105 insertions, 28 deletions
diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c
index fa636fc6b7b..becc42bb184 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -5,6 +5,7 @@
*
* Copyright (C) 1995 - 2000 by Ralf Baechle
*/
+#include <linux/context_tracking.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
@@ -16,23 +17,24 @@
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/smp.h>
-#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/module.h>
+#include <linux/kprobes.h>
+#include <linux/perf_event.h>
#include <asm/branch.h>
#include <asm/mmu_context.h>
-#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ptrace.h>
#include <asm/highmem.h> /* For VMALLOC_END */
+#include <linux/kdebug.h>
/*
* 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 do_page_fault(struct pt_regs *regs, unsigned long write,
- unsigned long address)
+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;
@@ -40,6 +42,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
const int field = sizeof(unsigned long) * 2;
siginfo_t info;
int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
#if 0
printk("Cpu%d[%s:%d:%0*lx:%ld:%0*lx]\n", raw_smp_processor_id(),
@@ -47,6 +50,17 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
field, regs->cp0_epc);
#endif
+#ifdef CONFIG_KPROBES
+ /*
+ * This is to notify the fault handler of the kprobes. The
+ * exception code is redundant as it is also carried in REGS,
+ * but we pass it anyhow.
+ */
+ if (notify_die(DIE_PAGE_FAULT, "page fault", regs, -1,
+ (regs->cp0_cause >> 2) & 0x1f, SIGSEGV) == NOTIFY_STOP)
+ return;
+#endif
+
info.si_code = SEGV_MAPERR;
/*
@@ -58,11 +72,17 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
* 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;
+ goto VMALLOC_FAULT_TARGET;
#ifdef MODULE_START
if (unlikely(address >= MODULE_START && address < MODULE_END))
- goto vmalloc_fault;
+ goto VMALLOC_FAULT_TARGET;
#endif
/*
@@ -72,6 +92,9 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write,
if (in_atomic() || !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)
@@ -92,18 +115,46 @@ good_area:
if (write) {
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
+ flags |= FAULT_FLAG_WRITE;
} else {
- if (!(vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)))
- goto bad_area;
+ 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)) {
+#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;
+ }
}
-survive:
/*
* 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, write);
+ fault = handle_mm_fault(mm, 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;
@@ -111,10 +162,29 @@ survive:
goto do_sigbus;
BUG();
}
- if (fault & VM_FAULT_MAJOR)
- tsk->maj_flt++;
- else
- tsk->min_flt++;
+ 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;
@@ -149,7 +219,7 @@ bad_area_nosemaphore:
}
no_context:
- /* Are we prepared to handle this kernel fault? */
+ /* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs)) {
current->thread.cp0_baduaddr = address;
return;
@@ -167,21 +237,16 @@ no_context:
field, regs->regs[31]);
die("Oops", regs);
-/*
- * We ran out of memory, or some other thing happened to us that made
- * us unable to handle the page fault gracefully.
- */
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 (is_global_init(tsk)) {
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- printk("VM: killing process %s\n", tsk->comm);
- if (user_mode(regs))
- do_group_exit(SIGKILL);
- goto no_context;
+ if (!user_mode(regs))
+ goto no_context;
+ pagefault_out_of_memory();
+ return;
do_sigbus:
up_read(&mm->mmap_sem);
@@ -211,6 +276,7 @@ do_sigbus:
force_sig_info(SIGBUS, &info, tsk);
return;
+#ifndef CONFIG_64BIT
vmalloc_fault:
{
/*
@@ -249,4 +315,15 @@ vmalloc_fault:
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);
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-10 03:27:07 +0000