Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android

[firefly-linux-kernel-4.4.55.git] / arch / arm64 / mm / fault.c

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 6c16e4963b39092a30ad444f1862d39d270538ae..7e4423d22d2823e68a4f12f85fc12b297ae2f867 100644 (file)
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -153,6 +153,11 @@ int ptep_set_access_flags(struct vm_area_struct *vma,
 }
 #endif
 
+static bool is_el1_instruction_abort(unsigned int esr)
+{
+       return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR;
+}
+
 /*
  * The kernel tried to access some page that wasn't present.
  */
@@ -161,8 +166,9 @@ static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
 {
        /*
         * Are we prepared to handle this kernel fault?
+        * We are almost certainly not prepared to handle instruction faults.
         */
-       if (fixup_exception(regs))
+       if (!is_el1_instruction_abort(esr) && fixup_exception(regs))
                return;
 
        /*
@@ -224,8 +230,6 @@ 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)
@@ -264,12 +268,24 @@ out:
        return fault;
 }
 
-static inline int permission_fault(unsigned int esr)
+static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs)
 {
-       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);
+       if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR)
+               return false;
+
+       if (system_uses_ttbr0_pan())
+               return fsc_type == ESR_ELx_FSC_FAULT &&
+                       (regs->pstate & PSR_PAN_BIT);
+       else
+               return 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,
@@ -301,17 +317,20 @@ 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 (addr < USER_DS && is_permission_fault(esr, regs)) {
                if (get_fs() == KERNEL_DS)
                        die("Accessing user space memory with fs=KERNEL_DS", regs, esr);
 
+               if (is_el1_instruction_abort(esr))
+                       die("Attempting to execute userspace memory", regs, esr);
+
                if (!search_exception_tables(regs->pc))
                        die("Accessing user space memory outside uaccess.h routines", regs, esr);
        }
@@ -463,7 +482,7 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs)
        return 1;
 }
 
-static struct fault_info {
+static const struct fault_info {
        int     (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs);
        int     sig;
        int     code;
@@ -489,10 +508,10 @@ static struct fault_info {
        { do_bad,               SIGBUS,  0,             "unknown 17"                    },
        { do_bad,               SIGBUS,  0,             "unknown 18"                    },
        { do_bad,               SIGBUS,  0,             "unknown 19"                    },
-       { do_bad,               SIGBUS,  0,             "synchronous abort (translation table walk)" },
-       { do_bad,               SIGBUS,  0,             "synchronous abort (translation table walk)" },
-       { do_bad,               SIGBUS,  0,             "synchronous abort (translation table walk)" },
-       { do_bad,               SIGBUS,  0,             "synchronous abort (translation table walk)" },
+       { do_bad,               SIGBUS,  0,             "synchronous external abort (translation table walk)" },
+       { do_bad,               SIGBUS,  0,             "synchronous external abort (translation table walk)" },
+       { do_bad,               SIGBUS,  0,             "synchronous external abort (translation table walk)" },
+       { do_bad,               SIGBUS,  0,             "synchronous external abort (translation table walk)" },
        { do_bad,               SIGBUS,  0,             "synchronous parity error"      },
        { do_bad,               SIGBUS,  0,             "unknown 25"                    },
        { do_bad,               SIGBUS,  0,             "unknown 26"                    },