aboutsummaryrefslogtreecommitdiff
path: root/arch/avr32/mm/fault.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/avr32/mm/fault.c')
-rw-r--r--arch/avr32/mm/fault.c229
1 files changed, 90 insertions, 139 deletions
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index 678557260a3..0eca9332719 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -12,73 +12,46 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/pagemap.h>
+#include <linux/kdebug.h>
+#include <linux/kprobes.h>
-#include <asm/kdebug.h>
#include <asm/mmu_context.h>
#include <asm/sysreg.h>
-#include <asm/uaccess.h>
#include <asm/tlb.h>
-
-#ifdef DEBUG
-static void dump_code(unsigned long pc)
-{
- char *p = (char *)pc;
- char val;
- int i;
-
-
- printk(KERN_DEBUG "Code:");
- for (i = 0; i < 16; i++) {
- if (__get_user(val, p + i))
- break;
- printk(" %02x", val);
- }
- printk("\n");
-}
-#endif
+#include <asm/uaccess.h>
#ifdef CONFIG_KPROBES
-ATOMIC_NOTIFIER_HEAD(notify_page_fault_chain);
-
-/* Hook to register for page fault notifications */
-int register_page_fault_notifier(struct notifier_block *nb)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
- return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
-}
+ int ret = 0;
-int unregister_page_fault_notifier(struct notifier_block *nb)
-{
- return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
-}
+ if (!user_mode(regs)) {
+ if (kprobe_running() && kprobe_fault_handler(regs, trap))
+ ret = 1;
+ }
-static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
- int trap, int sig)
-{
- struct die_args args = {
- .regs = regs,
- .trapnr = trap,
- };
- return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+ return ret;
}
#else
-static inline int notify_page_fault(enum die_val val, struct pt_regs *regs,
- int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs, int trap)
{
- return NOTIFY_DONE;
+ return 0;
}
#endif
+int exception_trace = 1;
+
/*
* This routine handles page faults. It determines the address and the
* problem, and then passes it off to one of the appropriate routines.
*
* ecr is the Exception Cause Register. Possible values are:
- * 5: Page not found (instruction access)
* 6: Protection fault (instruction access)
- * 12: Page not found (read access)
- * 13: Page not found (write access)
- * 14: Protection fault (read access)
- * 15: Protection fault (write access)
+ * 15: Protection fault (read access)
+ * 16: Protection fault (write access)
+ * 20: Page not found (instruction access)
+ * 24: Page not found (read access)
+ * 28: Page not found (write access)
*/
asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
{
@@ -88,10 +61,12 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
const struct exception_table_entry *fixup;
unsigned long address;
unsigned long page;
- int writeaccess = 0;
+ long signr;
+ int code;
+ int fault;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
- if (notify_page_fault(DIE_PAGE_FAULT, regs,
- ecr, SIGSEGV) == NOTIFY_STOP)
+ if (notify_page_fault(regs, ecr))
return;
address = sysreg_read(TLBEAR);
@@ -99,6 +74,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
tsk = current;
mm = tsk->mm;
+ signr = SIGSEGV;
+ code = SEGV_MAPERR;
+
/*
* If we're in an interrupt or have no user context, we must
* not take the fault...
@@ -108,6 +86,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
local_irq_enable();
+ if (user_mode(regs))
+ flags |= FAULT_FLAG_USER;
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
@@ -125,7 +106,8 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
* can handle it...
*/
good_area:
- //pr_debug("good area: vm_flags = 0x%lx\n", vma->vm_flags);
+ code = SEGV_ACCERR;
+
switch (ecr) {
case ECR_PROTECTION_X:
case ECR_TLB_MISS_X:
@@ -141,7 +123,7 @@ good_area:
case ECR_TLB_MISS_W:
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
- writeaccess = 1;
+ flags |= FAULT_FLAG_WRITE;
break;
default:
panic("Unhandled case %lu in do_page_fault!", ecr);
@@ -152,22 +134,37 @@ good_area:
* sure we exit gracefully rather than endlessly redo the
* fault.
*/
-survive:
- switch (handle_mm_fault(mm, vma, address, writeaccess)) {
- case VM_FAULT_MINOR:
- tsk->min_flt++;
- break;
- case VM_FAULT_MAJOR:
- tsk->maj_flt++;
- break;
- case VM_FAULT_SIGBUS:
- goto do_sigbus;
- case VM_FAULT_OOM:
- goto out_of_memory;
- default:
+ fault = handle_mm_fault(mm, vma, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return;
+
+ if (unlikely(fault & VM_FAULT_ERROR)) {
+ if (fault & VM_FAULT_OOM)
+ goto out_of_memory;
+ else if (fault & VM_FAULT_SIGBUS)
+ goto do_sigbus;
BUG();
}
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ 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;
@@ -176,46 +173,24 @@ survive:
* map. Fix it, but check if it's kernel or user first...
*/
bad_area:
- pr_debug("Bad area [%s:%u]: addr %08lx, ecr %lu\n",
- tsk->comm, tsk->pid, address, ecr);
-
up_read(&mm->mmap_sem);
if (user_mode(regs)) {
- /* Hmm...we have to pass address and ecr somehow... */
- /* tsk->thread.address = address;
- tsk->thread.error_code = ecr; */
-#ifdef DEBUG
- show_regs(regs);
- dump_code(regs->pc);
-
- page = sysreg_read(PTBR);
- printk("ptbr = %08lx", page);
- if (page) {
- page = ((unsigned long *)page)[address >> 22];
- printk(" pgd = %08lx", page);
- if (page & _PAGE_PRESENT) {
- page &= PAGE_MASK;
- address &= 0x003ff000;
- page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT];
- printk(" pte = %08lx\n", page);
- }
- }
-#endif
- pr_debug("Sending SIGSEGV to PID %d...\n",
- tsk->pid);
- force_sig(SIGSEGV, tsk);
+ if (exception_trace && printk_ratelimit())
+ printk("%s%s[%d]: segfault at %08lx pc %08lx "
+ "sp %08lx ecr %lu\n",
+ is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
+ tsk->comm, tsk->pid, address, regs->pc,
+ regs->sp, ecr);
+ _exception(SIGSEGV, regs, code, address);
return;
}
no_context:
- pr_debug("No context\n");
-
/* Are we prepared to handle this kernel fault? */
fixup = search_exception_tables(regs->pc);
if (fixup) {
regs->pc = fixup->fixup;
- pr_debug("Found fixup at %08lx\n", fixup->fixup);
return;
}
@@ -230,10 +205,11 @@ no_context:
printk(KERN_ALERT
"Unable to handle kernel paging request");
printk(" at virtual address %08lx\n", address);
- printk(KERN_ALERT "pc = %08lx\n", regs->pc);
page = sysreg_read(PTBR);
printk(KERN_ALERT "ptbr = %08lx", page);
+ if (address >= TASK_SIZE)
+ page = (unsigned long)swapper_pg_dir;
if (page) {
page = ((unsigned long *)page)[address >> 22];
printk(" pgd = %08lx", page);
@@ -241,47 +217,41 @@ no_context:
page &= PAGE_MASK;
address &= 0x003ff000;
page = ((unsigned long *)__va(page))[address >> PAGE_SHIFT];
- printk(" pte = %08lx\n", page);
+ printk(" pte = %08lx", page);
}
}
- die("\nOops", regs, ecr);
- do_exit(SIGKILL);
+ printk("\n");
+ die("Kernel access of bad area", regs, signr);
+ return;
/*
* 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:
- printk("Out of memory\n");
up_read(&mm->mmap_sem);
- if (current->pid == 1) {
- yield();
- down_read(&mm->mmap_sem);
- goto survive;
- }
- printk("VM: Killing process %s\n", tsk->comm);
- if (user_mode(regs))
- do_exit(SIGKILL);
- goto no_context;
+ if (!user_mode(regs))
+ goto no_context;
+ pagefault_out_of_memory();
+ return;
do_sigbus:
up_read(&mm->mmap_sem);
- /*
- * Send a sigbus, regardless of whether we were in kernel or
- * user mode.
- */
- /* address, error_code, trap_no, ... */
-#ifdef DEBUG
- show_regs(regs);
- dump_code(regs->pc);
-#endif
- pr_debug("Sending SIGBUS to PID %d...\n", tsk->pid);
- force_sig(SIGBUS, tsk);
-
/* Kernel mode? Handle exceptions or die */
+ signr = SIGBUS;
+ code = BUS_ADRERR;
if (!user_mode(regs))
goto no_context;
+
+ if (exception_trace)
+ printk("%s%s[%d]: bus error at %08lx pc %08lx "
+ "sp %08lx ecr %lu\n",
+ is_global_init(tsk) ? KERN_EMERG : KERN_INFO,
+ tsk->comm, tsk->pid, address, regs->pc,
+ regs->sp, ecr);
+
+ _exception(SIGBUS, regs, BUS_ADRERR, address);
}
asmlinkage void do_bus_error(unsigned long addr, int write_access,
@@ -292,24 +262,5 @@ asmlinkage void do_bus_error(unsigned long addr, int write_access,
addr, write_access ? "write" : "read");
printk(KERN_INFO "DTLB dump:\n");
dump_dtlb();
- die("Bus Error", regs, write_access);
- do_exit(SIGKILL);
+ die("Bus Error", regs, SIGKILL);
}
-
-/*
- * This functionality is currently not possible to implement because
- * we're using segmentation to ensure a fixed mapping of the kernel
- * virtual address space.
- *
- * It would be possible to implement this, but it would require us to
- * disable segmentation at startup and load the kernel mappings into
- * the TLB like any other pages. There will be lots of trickery to
- * avoid recursive invocation of the TLB miss handler, though...
- */
-#ifdef CONFIG_DEBUG_PAGEALLOC
-void kernel_map_pages(struct page *page, int numpages, int enable)
-{
-
-}
-EXPORT_SYMBOL(kernel_map_pages);
-#endif
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-06 10:06:12 +0000