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 e9b9b53643936a121e8c73db99373d7e7cab9b48..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;
 
@@ -139,24 +129,41 @@ 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)
 {
        struct stackframe frame;
+       unsigned long irq_stack_ptr;
+       int skip;
+
+       /*
+        * Switching between stacks is valid when tracing current and in
+        * non-preemptible context.
+        */
+       if (tsk == current && !preemptible())
+               irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
+       else
+               irq_stack_ptr = 0;
 
        pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
 
        if (!tsk)
                tsk = current;
 
-       if (regs) {
-               frame.fp = regs->regs[29];
-               frame.sp = regs->sp;
-               frame.pc = regs->pc;
-       } else if (tsk == current) {
+       if (tsk == current) {
                frame.fp = (unsigned long)__builtin_frame_address(0);
                frame.sp = current_stack_pointer;
                frame.pc = (unsigned long)dump_backtrace;
@@ -168,21 +175,49 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
                frame.sp = thread_saved_sp(tsk);
                frame.pc = thread_saved_pc(tsk);
        }
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+       frame.graph = tsk->curr_ret_stack;
+#endif
 
-       pr_emerg("Call trace:\n");
+       skip = !!regs;
+       printk("Call trace:\n");
        while (1) {
                unsigned long where = frame.pc;
                unsigned long stack;
                int ret;
 
-               dump_backtrace_entry(where);
-               ret = unwind_frame(&frame);
+               /* skip until specified stack frame */
+               if (!skip) {
+                       dump_backtrace_entry(where);
+               } else if (frame.fp == regs->regs[29]) {
+                       skip = 0;
+                       /*
+                        * Mostly, this is the case where this function is
+                        * called in panic/abort. As exception handler's
+                        * stack frame does not contain the corresponding pc
+                        * at which an exception has taken place, use regs->pc
+                        * instead.
+                        */
+                       dump_backtrace_entry(regs->pc);
+               }
+               ret = unwind_frame(tsk, &frame);
                if (ret < 0)
                        break;
                stack = frame.sp;
-               if (in_exception_text(where))
+               if (in_exception_text(where)) {
+                       /*
+                        * If we switched to the irq_stack before calling this
+                        * exception handler, then the pt_regs will be on the
+                        * task stack. The easiest way to tell is if the large
+                        * pt_regs would overlap with the end of the irq_stack.
+                        */
+                       if (stack < irq_stack_ptr &&
+                           (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
+                               stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
+
                        dump_mem("", "Exception stack", stack,
                                 stack + sizeof(struct pt_regs), false);
+               }
        }
 }
 
@@ -430,7 +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)];
 }
 
 /*
@@ -456,22 +491,22 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 
 void __pte_error(const char *file, int line, unsigned long val)
 {
-       pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
+       pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
 }
 
 void __pmd_error(const char *file, int line, unsigned long val)
 {
-       pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
+       pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
 }
 
 void __pud_error(const char *file, int line, unsigned long val)
 {
-       pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
+       pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
 }
 
 void __pgd_error(const char *file, int line, unsigned long val)
 {
-       pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
+       pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
 }
 
 /* GENERIC_BUG traps */