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-rw-r--r--arch/sh/mm/fault_32.c196
1 files changed, 121 insertions, 75 deletions
diff --git a/arch/sh/mm/fault_32.c b/arch/sh/mm/fault_32.c
index 7192594..781b413 100644
--- a/arch/sh/mm/fault_32.c
+++ b/arch/sh/mm/fault_32.c
@@ -2,7 +2,7 @@
* Page fault handler for SH with an MMU.
*
* Copyright (C) 1999 Niibe Yutaka
- * Copyright (C) 2003 - 2008 Paul Mundt
+ * Copyright (C) 2003 - 2009 Paul Mundt
*
* Based on linux/arch/i386/mm/fault.c:
* Copyright (C) 1995 Linus Torvalds
@@ -25,18 +25,91 @@ static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
int ret = 0;
-#ifdef CONFIG_KPROBES
- if (!user_mode(regs)) {
+ if (kprobes_built_in() && !user_mode(regs)) {
preempt_disable();
if (kprobe_running() && kprobe_fault_handler(regs, trap))
ret = 1;
preempt_enable();
}
-#endif
return ret;
}
+static inline pmd_t *vmalloc_sync_one(pgd_t *pgd, unsigned long address)
+{
+ unsigned index = pgd_index(address);
+ pgd_t *pgd_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;
+
+ pud = pud_offset(pgd, address);
+ pud_k = pud_offset(pgd_k, address);
+ if (!pud_present(*pud_k))
+ return NULL;
+
+ 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;
+}
+
+/*
+ * 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 < P3_ADDR_MAX))
+ 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 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
@@ -46,6 +119,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
unsigned long writeaccess,
unsigned long address)
{
+ unsigned long vec;
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
@@ -53,59 +127,30 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
int fault;
siginfo_t info;
- /*
- * We don't bother with any notifier callbacks here, as they are
- * all handled through the __do_page_fault() fast-path.
- */
-
tsk = current;
+ mm = tsk->mm;
si_code = SEGV_MAPERR;
+ vec = lookup_exception_vector();
- if (unlikely(address >= TASK_SIZE)) {
- /*
- * 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;
- pud_t *pud, *pud_k;
- pmd_t *pmd, *pmd_k;
-
- pgd = get_TTB() + offset;
- pgd_k = swapper_pg_dir + offset;
-
- if (!pgd_present(*pgd)) {
- if (!pgd_present(*pgd_k))
- goto bad_area_nosemaphore;
- set_pgd(pgd, *pgd_k);
+ /*
+ * 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;
- }
-
- pud = pud_offset(pgd, address);
- pud_k = pud_offset(pgd_k, address);
-
- if (!pud_present(*pud)) {
- if (!pud_present(*pud_k))
- goto bad_area_nosemaphore;
- set_pud(pud, *pud_k);
+ if (notify_page_fault(regs, vec))
return;
- }
- pmd = pmd_offset(pud, address);
- pmd_k = pmd_offset(pud_k, address);
- if (pmd_present(*pmd) || !pmd_present(*pmd_k))
- goto bad_area_nosemaphore;
- set_pmd(pmd, *pmd_k);
-
- return;
+ goto bad_area_nosemaphore;
}
- mm = tsk->mm;
-
- if (unlikely(notify_page_fault(regs, lookup_exception_vector())))
+ if (unlikely(notify_page_fault(regs, vec)))
return;
/* Only enable interrupts if they were on before the fault */
@@ -115,8 +160,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
perf_swcounter_event(PERF_COUNT_SW_PAGE_FAULTS, 1, 0, regs, address);
/*
- * If we're in an interrupt or have no user
- * context, we must not take the fault..
+ * If we're in an interrupt, have no user context or are running
+ * in an atomic region then we must not take the fault:
*/
if (in_atomic() || !mm)
goto no_context;
@@ -132,10 +177,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
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..
- */
+
+ /*
+ * Ok, we have a good vm_area for this memory access, so
+ * we can handle it..
+ */
good_area:
si_code = SEGV_ACCERR;
if (writeaccess) {
@@ -173,10 +219,10 @@ survive:
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..
- */
+ /*
+ * 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);
@@ -272,16 +318,15 @@ do_sigbus:
/*
* Called with interrupts disabled.
*/
-asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
- unsigned long writeaccess,
- unsigned long address)
+asmlinkage int __kprobes
+handle_tlbmiss(struct pt_regs *regs, unsigned long writeaccess,
+ unsigned long address)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t entry;
- int ret = 1;
/*
* We don't take page faults for P1, P2, and parts of P4, these
@@ -292,40 +337,41 @@ asmlinkage int __kprobes __do_page_fault(struct pt_regs *regs,
pgd = pgd_offset_k(address);
} else {
if (unlikely(address >= TASK_SIZE || !current->mm))
- goto out;
+ return 1;
pgd = pgd_offset(current->mm, address);
}
pud = pud_offset(pgd, address);
if (pud_none_or_clear_bad(pud))
- goto out;
+ return 1;
pmd = pmd_offset(pud, address);
if (pmd_none_or_clear_bad(pmd))
- goto out;
+ return 1;
pte = pte_offset_kernel(pmd, address);
entry = *pte;
if (unlikely(pte_none(entry) || pte_not_present(entry)))
- goto out;
+ return 1;
if (unlikely(writeaccess && !pte_write(entry)))
- goto out;
+ return 1;
if (writeaccess)
entry = pte_mkdirty(entry);
entry = pte_mkyoung(entry);
+ set_pte(pte, entry);
+
#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SMP)
/*
- * ITLB is not affected by "ldtlb" instruction.
- * So, we need to flush the entry by ourselves.
+ * SH-4 does not set MMUCR.RC to the corresponding TLB entry in
+ * the case of an initial page write exception, so we need to
+ * flush it in order to avoid potential TLB entry duplication.
*/
- local_flush_tlb_one(get_asid(), address & PAGE_MASK);
+ if (writeaccess == 2)
+ local_flush_tlb_one(get_asid(), address & PAGE_MASK);
#endif
- set_pte(pte, entry);
update_mmu_cache(NULL, address, entry);
- ret = 0;
-out:
- return ret;
+ return 0;
}
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