[POWERPC] PowerPC: Prevent data exception in kernel space (32-bit)

[sfrench/cifs-2.6.git] / arch / powerpc / mm / fault.c

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index e8fa50624b70dae41c27ce669e10f472b18970a8..115b25f50bf83786965380f041d301bad44218e0 100644 (file)
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -28,6 +28,7 @@
 #include <linux/highmem.h>
 #include <linux/module.h>
 #include <linux/kprobes.h>
+#include <linux/kdebug.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -36,40 +37,28 @@
 #include <asm/system.h>
 #include <asm/uaccess.h>
 #include <asm/tlbflush.h>
-#include <asm/kdebug.h>
 #include <asm/siginfo.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)
-{
-       return atomic_notifier_chain_register(&notify_page_fault_chain, nb);
-}
 
-int unregister_page_fault_notifier(struct notifier_block *nb)
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs)
 {
-       return atomic_notifier_chain_unregister(&notify_page_fault_chain, nb);
-}
+       int ret = 0;
+
+       /* kprobe_running() needs smp_processor_id() */
+       if (!user_mode(regs)) {
+               preempt_disable();
+               if (kprobe_running() && kprobe_fault_handler(regs, 11))
+                       ret = 1;
+               preempt_enable();
+       }
 
-static inline int notify_page_fault(enum die_val val, const char *str,
-                       struct pt_regs *regs, long err, int trap, int sig)
-{
-       struct die_args args = {
-               .regs = regs,
-               .str = str,
-               .err = err,
-               .trapnr = trap,
-               .signr = sig
-       };
-       return atomic_notifier_call_chain(&notify_page_fault_chain, val, &args);
+       return ret;
 }
 #else
-static inline int notify_page_fault(enum die_val val, const char *str,
-                       struct pt_regs *regs, long err, int trap, int sig)
+static inline int notify_page_fault(struct pt_regs *regs)
 {
-       return NOTIFY_DONE;
+       return 0;
 }
 #endif
 
@@ -175,8 +164,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
        is_write = error_code & ESR_DST;
 #endif /* CONFIG_4xx || CONFIG_BOOKE */
 
-       if (notify_page_fault(DIE_PAGE_FAULT, "page_fault", regs, error_code,
-                               11, SIGSEGV) == NOTIFY_STOP)
+       if (notify_page_fault(regs))
                return 0;
 
        if (trap == 0x300) {
@@ -291,14 +279,13 @@ good_area:
 #endif /* CONFIG_8xx */
 
        if (is_exec) {
-#ifdef CONFIG_PPC64
+#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
                /* protection fault */
                if (error_code & DSISR_PROTFAULT)
                        goto bad_area;
                if (!(vma->vm_flags & VM_EXEC))
                        goto bad_area;
-#endif
-#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
+#else
                pte_t *ptep;
                pmd_t *pmdp;
 
@@ -426,18 +413,21 @@ void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
 
        /* kernel has accessed a bad area */
 
-       printk(KERN_ALERT "Unable to handle kernel paging request for ");
        switch (regs->trap) {
-               case 0x300:
-               case 0x380:
-                       printk("data at address 0x%08lx\n", regs->dar);
-                       break;
-               case 0x400:
-               case 0x480:
-                       printk("instruction fetch\n");
-                       break;
-               default:
-                       printk("unknown fault\n");
+       case 0x300:
+       case 0x380:
+               printk(KERN_ALERT "Unable to handle kernel paging request for "
+                       "data at address 0x%08lx\n", regs->dar);
+               break;
+       case 0x400:
+       case 0x480:
+               printk(KERN_ALERT "Unable to handle kernel paging request for "
+                       "instruction fetch\n");
+               break;
+       default:
+               printk(KERN_ALERT "Unable to handle kernel paging request for "
+                       "unknown fault\n");
+               break;
        }
        printk(KERN_ALERT "Faulting instruction address: 0x%08lx\n",
                regs->nip);