dumpstack: x86: various small unification steps

- define STACKSLOTS_PER_LINE and use it
 - define get_bp macro to hide the %%ebp/%%rbp difference
 - i386: check task==NULL in dump_trace, like x86_64
 - i386: show_trace(NULL, ...) uses current automatically
 - x86_64: use [#%d] for die_counter, like i386
 - whitespace and comments

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 20 insertions, 18 deletions

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 9a8920abe4ba..201ee359a1a9 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -16,8 +16,11 @@
 
 #include <asm/stacktrace.h>
 
+#define STACKSLOTS_PER_LINE 8
+#define get_bp(bp) asm("movl %%ebp, %0" : "=r" (bp) :)
+
 int panic_on_unrecovered_nmi;
-int kstack_depth_to_print = 24;
+int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
 static unsigned int code_bytes = 64;
 static int die_counter;
 
@@ -82,7 +85,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
         if (!stack) {
                 unsigned long dummy;
                 stack = &dummy;
-                if (task != current)
+                if (task && task != current)
                         stack = (unsigned long *)task->thread.sp;
         }
 
@@ -90,7 +93,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
         if (!bp) {
                 if (task == current) {
                         /* Grab bp right from our regs */
-                        asm("movl %%ebp, %0" : "=r" (bp) :);
+                        get_bp(bp);
                 } else {
                         /* bp is the last reg pushed by switch_to */
                         bp = *(unsigned long *) task->thread.sp;
@@ -167,7 +170,7 @@ void show_trace(struct task_struct *task, struct pt_regs *regs,
 
 static void
 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
-                   unsigned long *sp, unsigned long bp, char *log_lvl)
+                unsigned long *sp, unsigned long bp, char *log_lvl)
 {
         unsigned long *stack;
         int i;
@@ -183,7 +186,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
         for (i = 0; i < kstack_depth_to_print; i++) {
                 if (kstack_end(stack))
                         break;
-                if (i && ((i % 8) == 0))
+                if (i && ((i % STACKSLOTS_PER_LINE) == 0))
                         printk("\n%s", log_lvl);
                 printk(" %08lx", *stack++);
                 touch_nmi_watchdog();
@@ -207,7 +210,7 @@ void dump_stack(void)
 
 #ifdef CONFIG_FRAME_POINTER
         if (!bp)
-                asm("movl %%ebp, %0" : "=r" (bp):);
+                get_bp(bp);
 #endif
 
         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
@@ -215,8 +218,7 @@ void dump_stack(void)
                 init_utsname()->release,
                 (int)strcspn(init_utsname()->version, " "),
                 init_utsname()->version);
-
-        show_trace(current, NULL, &stack, bp);
+        show_trace(NULL, NULL, &stack, bp);
 }
 
 EXPORT_SYMBOL(dump_stack);
@@ -249,7 +251,7 @@ void show_registers(struct pt_regs *regs)
 
                 ip = (u8 *)regs->ip - code_prologue;
                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
-                        /* try starting at EIP */
+                        /* try starting at IP */
                         ip = (u8 *)regs->ip;
                         code_len = code_len - code_prologue + 1;
                 }
@@ -317,13 +319,10 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 
         if (kexec_should_crash(current))
                 crash_kexec(regs);
-
         if (in_interrupt())
                 panic("Fatal exception in interrupt");
-
         if (panic_on_oops)
                 panic("Fatal exception");
-
         oops_exit();
         do_exit(signr);
 }
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 7fd32944ceac..13379a988292 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -16,8 +16,11 @@
 
 #include <asm/stacktrace.h>
 
+#define STACKSLOTS_PER_LINE 4
+#define get_bp(bp) asm("movl %%rbp, %0" : "=r" (bp) :)
+
 int panic_on_unrecovered_nmi;
-int kstack_depth_to_print = 12;
+int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
 static unsigned int code_bytes = 64;
 static int die_counter;
 
@@ -177,7 +180,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
         if (!bp) {
                 if (task == current) {
                         /* Grab bp right from our regs */
-                        asm("movq %%rbp, %0" : "=r" (bp) : );
+                        get_bp(bp);
                 } else {
                         /* bp is the last reg pushed by switch_to */
                         bp = *(unsigned long *) task->thread.sp;
@@ -329,7 +332,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
                 if (((long) stack & (THREAD_SIZE-1)) == 0)
                         break;
                 }
-                if (i && ((i % 4) == 0))
+                if (i && ((i % STACKSLOTS_PER_LINE) == 0))
                         printk("\n%s", log_lvl);
                 printk(" %016lx", *stack++);
                 touch_nmi_watchdog();
@@ -353,7 +356,7 @@ void dump_stack(void)
 
 #ifdef CONFIG_FRAME_POINTER
         if (!bp)
-                asm("movq %%rbp, %0" : "=r" (bp) : );
+                get_bp(bp);
 #endif
 
         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
@@ -396,7 +399,7 @@ void show_registers(struct pt_regs *regs)
 
                 ip = (u8 *)regs->ip - code_prologue;
                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
-                        /* try starting at RIP */
+                        /* try starting at IP */
                         ip = (u8 *)regs->ip;
                         code_len = code_len - code_prologue + 1;
                 }
@@ -475,7 +478,7 @@ void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 
 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 {
-        printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff, ++die_counter);
+        printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 #ifdef CONFIG_PREEMPT
         printk("PREEMPT ");
 #endif