BACKPORT: arm64: Disable TTBR0_EL1 during normal kernel execution

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

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index c5392081b49ba4ac4f48d9a0782442ac888ed222..29d7b68f63f091a0d4266ed64501ab35a41b2d5c 100644 (file)
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -64,8 +64,7 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
 
        /*
         * We need to switch to kernel mode so that we can use __get_user
-        * to safely read from kernel space.  Note that we now dump the
-        * code first, just in case the backtrace kills us.
+        * to safely read from kernel space.
         */
        fs = get_fs();
        set_fs(KERNEL_DS);
@@ -111,21 +110,12 @@ static void dump_backtrace_entry(unsigned long where)
        print_ip_sym(where);
 }
 
-static void dump_instr(const char *lvl, struct pt_regs *regs)
+static void __dump_instr(const char *lvl, struct pt_regs *regs)
 {
        unsigned long addr = instruction_pointer(regs);
-       mm_segment_t fs;
        char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
        int i;
 
-       /*
-        * We need to switch to kernel mode so that we can use __get_user
-        * to safely read from kernel space.  Note that we now dump the
-        * code first, just in case the backtrace kills us.
-        */
-       fs = get_fs();
-       set_fs(KERNEL_DS);
-
        for (i = -4; i < 1; i++) {
                unsigned int val, bad;
 
@@ -139,8 +129,18 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
                }
        }
        printk("%sCode: %s\n", lvl, str);
+}
 
-       set_fs(fs);
+static void dump_instr(const char *lvl, struct pt_regs *regs)
+{
+       if (!user_mode(regs)) {
+               mm_segment_t fs = get_fs();
+               set_fs(KERNEL_DS);
+               __dump_instr(lvl, regs);
+               set_fs(fs);
+       } else {
+               __dump_instr(lvl, regs);
+       }
 }
 
 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
@@ -465,7 +465,7 @@ static const char *esr_class_str[] = {
 
 const char *esr_get_class_string(u32 esr)
 {
-       return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
+       return esr_class_str[ESR_ELx_EC(esr)];
 }
 
 /*