Pull button into test branch
[linux-drm-fsl-dcu.git] / arch / x86_64 / kernel / traps.c
index a153d0a01b72152fa34b5fc22cfeec9a2c6ffda3..b54ccc07f37944dba409ac9a27761c5d5e0ce848 100644 (file)
 #include <linux/kprobes.h>
 #include <linux/kexec.h>
 #include <linux/unwind.h>
+#include <linux/uaccess.h>
+#include <linux/bug.h>
 
 #include <asm/system.h>
-#include <asm/uaccess.h>
 #include <asm/io.h>
 #include <asm/atomic.h>
 #include <asm/debugreg.h>
@@ -108,7 +109,7 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
        preempt_enable_no_resched();
 }
 
-static int kstack_depth_to_print = 12;
+int kstack_depth_to_print = 12;
 #ifdef CONFIG_STACK_UNWIND
 static int call_trace = 1;
 #else
@@ -225,16 +226,25 @@ static int dump_trace_unwind(struct unwind_frame_info *info, void *context)
 {
        struct ops_and_data *oad = (struct ops_and_data *)context;
        int n = 0;
+       unsigned long sp = UNW_SP(info);
 
+       if (arch_unw_user_mode(info))
+               return -1;
        while (unwind(info) == 0 && UNW_PC(info)) {
                n++;
                oad->ops->address(oad->data, UNW_PC(info));
                if (arch_unw_user_mode(info))
                        break;
+               if ((sp & ~(PAGE_SIZE - 1)) == (UNW_SP(info) & ~(PAGE_SIZE - 1))
+                   && sp > UNW_SP(info))
+                       break;
+               sp = UNW_SP(info);
        }
        return n;
 }
 
+#define MSG(txt) ops->warning(data, txt)
+
 /*
  * x86-64 can have upto three kernel stacks: 
  * process stack
@@ -242,12 +252,20 @@ static int dump_trace_unwind(struct unwind_frame_info *info, void *context)
  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  */
 
-void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * stack,
+static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
+{
+       void *t = (void *)tinfo;
+        return p > t && p < t + THREAD_SIZE - 3;
+}
+
+void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
+               unsigned long *stack,
                struct stacktrace_ops *ops, void *data)
 {
-       const unsigned cpu = smp_processor_id();
-       unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr;
+       const unsigned cpu = get_cpu();
+       unsigned long *irqstack_end = (unsigned long*)cpu_pda(cpu)->irqstackptr;
        unsigned used = 0;
+       struct thread_info *tinfo;
 
        if (!tsk)
                tsk = current;
@@ -261,28 +279,30 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
                        if (unwind_init_frame_info(&info, tsk, regs) == 0)
                                unw_ret = dump_trace_unwind(&info, &oad);
                } else if (tsk == current)
-                       unw_ret = unwind_init_running(&info, dump_trace_unwind, &oad);
+                       unw_ret = unwind_init_running(&info, dump_trace_unwind,
+                                                     &oad);
                else {
                        if (unwind_init_blocked(&info, tsk) == 0)
                                unw_ret = dump_trace_unwind(&info, &oad);
                }
                if (unw_ret > 0) {
                        if (call_trace == 1 && !arch_unw_user_mode(&info)) {
-                               ops->warning_symbol(data, "DWARF2 unwinder stuck at %s\n",
+                               ops->warning_symbol(data,
+                                            "DWARF2 unwinder stuck at %s",
                                             UNW_PC(&info));
                                if ((long)UNW_SP(&info) < 0) {
-                                       ops->warning(data, "Leftover inexact backtrace:\n");
+                                       MSG("Leftover inexact backtrace:");
                                        stack = (unsigned long *)UNW_SP(&info);
                                        if (!stack)
-                                               return;
+                                               goto out;
                                } else
-                                       ops->warning(data, "Full inexact backtrace again:\n");
+                                       MSG("Full inexact backtrace again:");
                        } else if (call_trace >= 1)
-                               return;
+                               goto out;
                        else
-                               ops->warning(data, "Full inexact backtrace again:\n");
+                               MSG("Full inexact backtrace again:");
                } else
-                       ops->warning(data, "Inexact backtrace:\n");
+                       MSG("Inexact backtrace:");
        }
        if (!stack) {
                unsigned long dummy;
@@ -290,12 +310,6 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
                if (tsk && tsk != current)
                        stack = (unsigned long *)tsk->thread.rsp;
        }
-       /*
-        * Align the stack pointer on word boundary, later loops
-        * rely on that (and corruption / debug info bugs can cause
-        * unaligned values here):
-        */
-       stack = (unsigned long *)((unsigned long)stack & ~(sizeof(long)-1));
 
        /*
         * Print function call entries within a stack. 'cond' is the
@@ -305,9 +319,9 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
 #define HANDLE_STACK(cond) \
        do while (cond) { \
                unsigned long addr = *stack++; \
-               if (oops_in_progress ?          \
-                       __kernel_text_address(addr) : \
-                       kernel_text_address(addr)) { \
+               /* Use unlocked access here because except for NMIs     \
+                  we should be already protected against module unloads */ \
+               if (__kernel_text_address(addr)) { \
                        /* \
                         * If the address is either in the text segment of the \
                         * kernel, or in the region which contains vmalloc'ed \
@@ -370,8 +384,11 @@ void dump_trace(struct task_struct *tsk, struct pt_regs *regs, unsigned long * s
        /*
         * This handles the process stack:
         */
-       HANDLE_STACK (((long) stack & (THREAD_SIZE-1)) != 0);
+       tinfo = current_thread_info();
+       HANDLE_STACK (valid_stack_ptr(tinfo, stack));
 #undef HANDLE_STACK
+out:
+       put_cpu();
 }
 EXPORT_SYMBOL(dump_trace);
 
@@ -508,30 +525,15 @@ bad:
        printk("\n");
 }      
 
-void handle_BUG(struct pt_regs *regs)
-{ 
-       struct bug_frame f;
-       long len;
-       const char *prefix = "";
+int is_valid_bugaddr(unsigned long rip)
+{
+       unsigned short ud2;
 
-       if (user_mode(regs))
-               return; 
-       if (__copy_from_user(&f, (const void __user *) regs->rip,
-                            sizeof(struct bug_frame)))
-               return; 
-       if (f.filename >= 0 ||
-           f.ud2[0] != 0x0f || f.ud2[1] != 0x0b) 
-               return;
-       len = __strnlen_user((char *)(long)f.filename, PATH_MAX) - 1;
-       if (len < 0 || len >= PATH_MAX)
-               f.filename = (int)(long)"unmapped filename";
-       else if (len > 50) {
-               f.filename += len - 50;
-               prefix = "...";
-       }
-       printk("----------- [cut here ] --------- [please bite here ] ---------\n");
-       printk(KERN_ALERT "Kernel BUG at %s%.50s:%d\n", prefix, (char *)(long)f.filename, f.line);
-} 
+       if (__copy_from_user(&ud2, (const void __user *) rip, sizeof(ud2)))
+               return 0;
+
+       return ud2 == 0x0b0f;
+}
 
 #ifdef CONFIG_BUG
 void out_of_line_bug(void)
@@ -611,7 +613,9 @@ void die(const char * str, struct pt_regs * regs, long err)
 {
        unsigned long flags = oops_begin();
 
-       handle_BUG(regs);
+       if (!user_mode(regs))
+               report_bug(regs->rip);
+
        __die(str, regs, err);
        oops_end(flags);
        do_exit(SIGSEGV); 
@@ -778,8 +782,7 @@ mem_parity_error(unsigned char reason, struct pt_regs * regs)
 {
        printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n",
                reason);
-       printk(KERN_EMERG "You probably have a hardware problem with your "
-               "RAM chips\n");
+       printk(KERN_EMERG "You have some hardware problem, likely on the PCI bus.\n");
 
        if (panic_on_unrecovered_nmi)
                panic("NMI: Not continuing");