Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64...

[cascardo/linux.git] / arch / arm64 / mm / fault.c

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 031820d..c8beaa0 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -41,6 +41,28 @@
 
 static const char *fault_name(unsigned int esr);
 
+#ifdef CONFIG_KPROBES
+static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
+{
+       int ret = 0;
+
+       /* kprobe_running() needs smp_processor_id() */
+       if (!user_mode(regs)) {
+               preempt_disable();
+               if (kprobe_running() && kprobe_fault_handler(regs, esr))
+                       ret = 1;
+               preempt_enable();
+       }
+
+       return ret;
+}
+#else
+static inline int notify_page_fault(struct pt_regs *regs, unsigned int esr)
+{
+       return 0;
+}
+#endif
+
 /*
  * Dump out the page tables associated with 'addr' in mm 'mm'.
  */
@@ -202,8 +224,6 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
 #define VM_FAULT_BADMAP                0x010000
 #define VM_FAULT_BADACCESS     0x020000
 
-#define ESR_LNX_EXEC           (1 << 24)
-
 static int __do_page_fault(struct mm_struct *mm, unsigned long addr,
                           unsigned int mm_flags, unsigned long vm_flags,
                           struct task_struct *tsk)
@@ -242,14 +262,19 @@ out:
        return fault;
 }
 
-static inline int permission_fault(unsigned int esr)
+static inline bool is_permission_fault(unsigned int esr)
 {
-       unsigned int ec       = (esr & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT;
+       unsigned int ec       = ESR_ELx_EC(esr);
        unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
 
        return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM);
 }
 
+static bool is_el0_instruction_abort(unsigned int esr)
+{
+       return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
+}
+
 static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
                                   struct pt_regs *regs)
 {
@@ -259,6 +284,9 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
        unsigned long vm_flags = VM_READ | VM_WRITE | VM_EXEC;
        unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 
+       if (notify_page_fault(regs, esr))
+               return 0;
+
        tsk = current;
        mm  = tsk->mm;
 
@@ -272,14 +300,14 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
        if (user_mode(regs))
                mm_flags |= FAULT_FLAG_USER;
 
-       if (esr & ESR_LNX_EXEC) {
+       if (is_el0_instruction_abort(esr)) {
                vm_flags = VM_EXEC;
        } else if ((esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM)) {
                vm_flags = VM_WRITE;
                mm_flags |= FAULT_FLAG_WRITE;
        }
 
-       if (permission_fault(esr) && (addr < USER_DS)) {
+       if (is_permission_fault(esr) && (addr < USER_DS)) {
                /* regs->orig_addr_limit may be 0 if we entered from EL0 */
                if (regs->orig_addr_limit == KERNEL_DS)
                        die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
@@ -630,6 +658,7 @@ asmlinkage int __exception do_debug_exception(unsigned long addr,
 
        return rv;
 }
+NOKPROBE_SYMBOL(do_debug_exception);
 
 #ifdef CONFIG_ARM64_PAN
 void cpu_enable_pan(void *__unused)