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authorSteven J. Magnani <steve@digidescorp.com>2010-04-27 12:37:54 -0500
committerMichal Simek <monstr@monstr.eu>2010-08-04 10:22:35 +0200
commitce3266c047389443d5f433d605c769e878cbe46e (patch)
treee638a255d5d0f1b000a81b512dc605b92d0b8701 /arch/microblaze/kernel/traps.c
parentba9c4f88d747836bf35c3eee36aa18d2e164f493 (diff)
downloadop-kernel-dev-ce3266c047389443d5f433d605c769e878cbe46e.zip
op-kernel-dev-ce3266c047389443d5f433d605c769e878cbe46e.tar.gz
microblaze: Add stack unwinder
Implement intelligent backtracing by searching for stack frame creation, and emitting only return addresses. Use print_hex_dump() to display the entire binary kernel stack. Limitation: MMU kernels are not currently able to trace beyond a system trap (interrupt, syscall, etc.). It is the intent of this patch to provide infrastructure that can be extended to add this capability later. Changes from V1: * Removed checks in find_frame_creation() that prevented location of the frame creation instruction in heavily optimized code * Various formatting/commenting/file location tweaks per review comments * Dropped Kconfig option to enable STACKTRACE as something logically separate Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Diffstat (limited to 'arch/microblaze/kernel/traps.c')
-rw-r--r--arch/microblaze/kernel/traps.c91
1 files changed, 40 insertions, 51 deletions
diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c
index 75e4920..ba034d4 100644
--- a/arch/microblaze/kernel/traps.c
+++ b/arch/microblaze/kernel/traps.c
@@ -16,13 +16,14 @@
#include <asm/exceptions.h>
#include <asm/system.h>
+#include <asm/unwind.h>
void trap_init(void)
{
__enable_hw_exceptions();
}
-static unsigned long kstack_depth_to_print = 24;
+static unsigned long kstack_depth_to_print; /* 0 == entire stack */
static int __init kstack_setup(char *s)
{
@@ -30,31 +31,47 @@ static int __init kstack_setup(char *s)
}
__setup("kstack=", kstack_setup);
-void show_trace(struct task_struct *task, unsigned long *stack)
+void show_stack(struct task_struct *task, unsigned long *sp)
{
- unsigned long addr;
-
- if (!stack)
- stack = (unsigned long *)&stack;
+ unsigned long words_to_show;
+ u32 fp = (u32) sp;
+
+ if (fp == 0) {
+ if (task) {
+ fp = ((struct thread_info *)
+ (task->stack))->cpu_context.r1;
+ } else {
+ /* Pick up caller of dump_stack() */
+ fp = (u32)&sp - 8;
+ }
+ }
- printk(KERN_NOTICE "Call Trace: ");
-#ifdef CONFIG_KALLSYMS
- printk(KERN_NOTICE "\n");
-#endif
- while (!kstack_end(stack)) {
- addr = *stack++;
- /*
- * If the address is either in the text segment of the
- * kernel, or in the region which contains vmalloc'ed
- * memory, it *may* be the address of a calling
- * routine; if so, print it so that someone tracing
- * down the cause of the crash will be able to figure
- * out the call path that was taken.
- */
- if (kernel_text_address(addr))
- print_ip_sym(addr);
+ words_to_show = (THREAD_SIZE - (fp & (THREAD_SIZE - 1))) >> 2;
+ if (kstack_depth_to_print && (words_to_show > kstack_depth_to_print))
+ words_to_show = kstack_depth_to_print;
+
+ pr_info("Kernel Stack:\n");
+
+ /*
+ * Make the first line an 'odd' size if necessary to get
+ * remaining lines to start at an address multiple of 0x10
+ */
+ if (fp & 0xF) {
+ unsigned long line1_words = (0x10 - (fp & 0xF)) >> 2;
+ if (line1_words < words_to_show) {
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32,
+ 4, (void *)fp, line1_words << 2, 0);
+ fp += line1_words << 2;
+ words_to_show -= line1_words;
+ }
}
- printk(KERN_NOTICE "\n");
+ print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
+ words_to_show << 2, 0);
+ printk(KERN_INFO "\n\n");
+
+ pr_info("Call Trace:\n");
+ microblaze_unwind(task, NULL);
+ pr_info("\n");
if (!task)
task = current;
@@ -62,34 +79,6 @@ void show_trace(struct task_struct *task, unsigned long *stack)
debug_show_held_locks(task);
}
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
- unsigned long *stack;
- int i;
-
- if (sp == NULL) {
- if (task)
- sp = (unsigned long *) ((struct thread_info *)
- (task->stack))->cpu_context.r1;
- else
- sp = (unsigned long *)&sp;
- }
-
- stack = sp;
-
- printk(KERN_INFO "\nStack:\n ");
-
- for (i = 0; i < kstack_depth_to_print; i++) {
- if (kstack_end(sp))
- break;
- if (i && ((i % 8) == 0))
- printk("\n ");
- printk("%08lx ", *sp++);
- }
- printk("\n");
- show_trace(task, stack);
-}
-
void dump_stack(void)
{
show_stack(NULL, NULL);
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