aboutsummaryrefslogtreecommitdiff
path: root/arch/ia64/mm/fault.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/ia64/mm/fault.c')
-rw-r--r--arch/ia64/mm/fault.c135
1 files changed, 94 insertions, 41 deletions
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index af7eb087dca..7225dad8709 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -7,17 +7,38 @@
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
-#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/prefetch.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
-#include <asm/system.h>
#include <asm/uaccess.h>
-#include <asm/kdebug.h>
-extern void die (char *, struct pt_regs *, long);
+extern int die(char *, struct pt_regs *, long);
+
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+ int ret = 0;
+
+ if (!user_mode(regs)) {
+ /* kprobe_running() needs smp_processor_id() */
+ preempt_disable();
+ if (kprobe_running() && kprobe_fault_handler(regs, trap))
+ ret = 1;
+ preempt_enable();
+ }
+
+ return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
+{
+ return 0;
+}
+#endif
/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
@@ -51,6 +72,10 @@ mapped_kernel_page_is_present (unsigned long address)
return pte_present(pte);
}
+# define VM_READ_BIT 0
+# define VM_WRITE_BIT 1
+# define VM_EXEC_BIT 2
+
void __kprobes
ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *regs)
{
@@ -59,6 +84,14 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
struct mm_struct *mm = current->mm;
struct siginfo si;
unsigned long mask;
+ int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
+
+ mask = ((((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
+ | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT));
+
+ /* mmap_sem is performance critical.... */
+ prefetchw(&mm->mmap_sem);
/*
* If we're in an interrupt or have no user context, we must not take the fault..
@@ -81,18 +114,28 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
/*
* This is to handle the kprobes on user space access instructions
*/
- if (notify_die(DIE_PAGE_FAULT, "page fault", regs, code, TRAP_BRKPT,
- SIGSEGV) == NOTIFY_STOP)
+ if (notify_page_fault(regs, TRAP_BRKPT))
return;
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+ if (mask & VM_WRITE)
+ flags |= FAULT_FLAG_WRITE;
+retry:
down_read(&mm->mmap_sem);
vma = find_vma_prev(mm, address, &prev_vma);
- if (!vma)
+ if (!vma && !prev_vma )
goto bad_area;
- /* find_vma_prev() returns vma such that address < vma->vm_end or NULL */
- if (address < vma->vm_start)
+ /*
+ * find_vma_prev() returns vma such that address < vma->vm_end or NULL
+ *
+ * May find no vma, but could be that the last vm area is the
+ * register backing store that needs to expand upwards, in
+ * this case vma will be null, but prev_vma will ne non-null
+ */
+ if (( !vma && prev_vma ) || (address < vma->vm_start) )
goto check_expansion;
good_area:
@@ -100,53 +143,67 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
/* OK, we've got a good vm_area for this memory area. Check the access permissions: */
-# define VM_READ_BIT 0
-# define VM_WRITE_BIT 1
-# define VM_EXEC_BIT 2
-
# if (((1 << VM_READ_BIT) != VM_READ || (1 << VM_WRITE_BIT) != VM_WRITE) \
|| (1 << VM_EXEC_BIT) != VM_EXEC)
# error File is out of sync with <linux/mm.h>. Please update.
# endif
- mask = ( (((isr >> IA64_ISR_X_BIT) & 1UL) << VM_EXEC_BIT)
- | (((isr >> IA64_ISR_W_BIT) & 1UL) << VM_WRITE_BIT)
- | (((isr >> IA64_ISR_R_BIT) & 1UL) << VM_READ_BIT));
+ if (((isr >> IA64_ISR_R_BIT) & 1UL) && (!(vma->vm_flags & (VM_READ | VM_WRITE))))
+ goto bad_area;
if ((vma->vm_flags & mask) != mask)
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.
*/
- switch (handle_mm_fault(mm, vma, address, (mask & VM_WRITE) != 0)) {
- case VM_FAULT_MINOR:
- ++current->min_flt;
- break;
- case VM_FAULT_MAJOR:
- ++current->maj_flt;
- break;
- case VM_FAULT_SIGBUS:
+ fault = handle_mm_fault(mm, vma, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return;
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
/*
* We ran out of memory, or some other thing happened
* to us that made us unable to handle the page fault
* gracefully.
*/
- signal = SIGBUS;
- goto bad_area;
- case VM_FAULT_OOM:
- goto out_of_memory;
- default:
+ if (fault & VM_FAULT_OOM) {
+ goto out_of_memory;
+ } else if (fault & VM_FAULT_SIGBUS) {
+ signal = SIGBUS;
+ goto bad_area;
+ }
BUG();
}
+
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->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;
check_expansion:
if (!(prev_vma && (prev_vma->vm_flags & VM_GROWSUP) && (address == prev_vma->vm_end))) {
+ if (!vma)
+ goto bad_area;
if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area;
if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
@@ -234,20 +291,16 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
else
printk(KERN_ALERT "Unable to handle kernel paging request at "
"virtual address %016lx\n", address);
- die("Oops", regs, isr);
+ if (die("Oops", regs, isr))
+ regs = NULL;
bust_spinlocks(0);
- do_exit(SIGKILL);
+ if (regs)
+ do_exit(SIGKILL);
return;
out_of_memory:
up_read(&mm->mmap_sem);
- if (current->pid == 1) {
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- printk(KERN_CRIT "VM: killing process %s\n", current->comm);
- if (user_mode(regs))
- do_exit(SIGKILL);
- goto no_context;
+ if (!user_mode(regs))
+ goto no_context;
+ pagefault_out_of_memory();
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-05 17:28:05 +0000