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SubjectRe: [PATCH 1/2] microblaze: add stack unwinder
Steven J. Magnani wrote:
> 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.
>
> Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
> ---
> diff -uprN a/arch/microblaze/include/asm/exceptions.h b/arch/microblaze/include/asm/exceptions.h
> --- a/arch/microblaze/include/asm/exceptions.h 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/include/asm/exceptions.h 2010-04-12 22:21:01.000000000 -0500
> @@ -14,6 +14,11 @@
> #define _ASM_MICROBLAZE_EXCEPTIONS_H
>
> #ifdef __KERNEL__
> +
> +#ifndef CONFIG_MMU
> +#define EX_HANDLER_STACK_SIZ (4*19)
> +#endif
> +
> #ifndef __ASSEMBLY__
>
> /* Macros to enable and disable HW exceptions in the MSR */
> diff -uprN a/arch/microblaze/include/asm/system.h b/arch/microblaze/include/asm/system.h
> --- a/arch/microblaze/include/asm/system.h 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/include/asm/system.h 2010-04-12 22:16:01.000000000 -0500
> @@ -44,7 +44,6 @@ extern struct task_struct *_switch_to(st
> #define smp_rmb() rmb()
> #define smp_wmb() wmb()
>
> -void show_trace(struct task_struct *task, unsigned long *stack);
> void __bad_xchg(volatile void *ptr, int size);
>
> static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
> diff -uprN a/arch/microblaze/kernel/entry-nommu.S b/arch/microblaze/kernel/entry-nommu.S
> --- a/arch/microblaze/kernel/entry-nommu.S 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/kernel/entry-nommu.S 2010-04-12 22:16:01.000000000 -0500
> @@ -586,3 +586,31 @@ sys_rt_sigsuspend_wrapper:
> #include "syscall_table.S"
>
> syscall_table_size=(.-sys_call_table)
> +
> +type_SYSCALL:
> + .ascii "SYSCALL\0"
> +type_IRQ:
> + .ascii "IRQ\0"
> +type_IRQ_PREEMPT:
> + .ascii "IRQ (PREEMPTED)\0"
> +type_SYSCALL_PREEMPT:
> + .ascii " SYSCALL (PREEMPTED)\0"
> +
> + /*
> + * Trap decoding for stack unwinder
> + * Tuples are (start addr, end addr, string)
> + * If return address lies on [start addr, end addr],
> + * unwinder displays 'string'
> + */
> +
> + .align 4
> +.global microblaze_trap_handlers
> +microblaze_trap_handlers:
> + /* Exact matches come first */
> + .word ret_to_user ; .word ret_to_user ; .word type_SYSCALL
> + .word ret_from_intr; .word ret_from_intr ; .word type_IRQ
> + /* Fuzzy matches go here */
> + .word ret_from_intr; .word no_intr_resched; .word type_IRQ_PREEMPT
> + .word work_pending ; .word no_work_pending; .word type_SYSCALL_PREEMPT
> + /* End of table */
> + .word 0 ; .word 0 ; .word 0
> diff -uprN a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
> --- a/arch/microblaze/kernel/entry.S 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/kernel/entry.S 2010-04-12 22:16:01.000000000 -0500
> @@ -1127,3 +1127,30 @@ ENTRY(_break)
>
> syscall_table_size=(.-sys_call_table)
>
> +type_SYSCALL:
> + .ascii "SYSCALL\0"
> +type_IRQ:
> + .ascii "IRQ\0"
> +type_IRQ_PREEMPT:
> + .ascii "IRQ (PREEMPTED)\0"
> +type_SYSCALL_PREEMPT:
> + .ascii " SYSCALL (PREEMPTED)\0"
> +
> + /*
> + * Trap decoding for stack unwinder
> + * Tuples are (start addr, end addr, string)
> + * If return address lies on [start addr, end addr],
> + * unwinder displays 'string'
> + */
> +
> + .align 4
> +.global microblaze_trap_handlers
> +microblaze_trap_handlers:
> + /* Exact matches come first */
> + .word ret_from_trap; .word ret_from_trap ; .word type_SYSCALL
> + .word ret_from_irq ; .word ret_from_irq ; .word type_IRQ
> + /* Fuzzy matches go here */
> + .word ret_from_irq ; .word no_intr_resched ; .word type_IRQ_PREEMPT
> + .word ret_from_trap; .word TRAP_return ; .word type_SYSCALL_PREEMPT
> + /* End of table */
> + .word 0 ; .word 0 ; .word 0
> diff -uprN a/arch/microblaze/kernel/hw_exception_handler.S b/arch/microblaze/kernel/hw_exception_handler.S
> --- a/arch/microblaze/kernel/hw_exception_handler.S 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/kernel/hw_exception_handler.S 2010-04-12 22:21:15.000000000 -0500
> @@ -78,9 +78,6 @@
> #include <asm/asm-offsets.h>
>
> /* Helpful Macros */
> -#ifndef CONFIG_MMU
> -#define EX_HANDLER_STACK_SIZ (4*19)
> -#endif
> #define NUM_TO_REG(num) r ## num
>
> #ifdef CONFIG_MMU
> @@ -988,6 +985,7 @@ ex_unaligned_fixup:
> .end _unaligned_data_exception
> #endif /* CONFIG_MMU */
>
> +.global ex_handler_unhandled
> ex_handler_unhandled:
> /* FIXME add handle function for unhandled exception - dump register */
> bri 0
> diff -uprN a/arch/microblaze/kernel/Makefile b/arch/microblaze/kernel/Makefile
> --- a/arch/microblaze/kernel/Makefile 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/kernel/Makefile 2010-04-12 22:16:01.000000000 -0500
> @@ -17,7 +17,8 @@ extra-y := head.o vmlinux.lds
> obj-y += dma.o exceptions.o \
> hw_exception_handler.o init_task.o intc.o irq.o of_device.o \
> of_platform.o process.o prom.o prom_parse.o ptrace.o \
> - setup.o signal.o sys_microblaze.o timer.o traps.o reset.o
> + setup.o signal.o sys_microblaze.o timer.o traps.o reset.o \
> + unwind.o

It is not your fault but please sort this list - reset to front of the list.

>
> obj-y += cpu/
>
> diff -uprN a/arch/microblaze/kernel/stacktrace.c b/arch/microblaze/kernel/stacktrace.c
> --- a/arch/microblaze/kernel/stacktrace.c 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/kernel/stacktrace.c 2010-04-12 22:16:01.000000000 -0500
> @@ -14,52 +14,18 @@
> #include <linux/thread_info.h>
> #include <linux/ptrace.h>
> #include <linux/module.h>
> +#include "unwind.h"

asm/

>
> -/* FIXME initial support */
> void save_stack_trace(struct stack_trace *trace)
> {
> - unsigned long *sp;
> - unsigned long addr;
> - asm("addik %0, r1, 0" : "=r" (sp));
> -
> - while (!kstack_end(sp)) {
> - addr = *sp++;
> - if (__kernel_text_address(addr)) {
> - if (trace->skip > 0)
> - trace->skip--;
> - else
> - trace->entries[trace->nr_entries++] = addr;
> -
> - if (trace->nr_entries >= trace->max_entries)
> - break;
> - }
> - }
> + /* Exclude our helper functions from the trace*/
> + trace->skip += 2;
> + microblaze_unwind(NULL, trace);
> }
> EXPORT_SYMBOL_GPL(save_stack_trace);
>
> void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
> {
> - unsigned int *sp;
> - unsigned long addr;
> -
> - struct thread_info *ti = task_thread_info(tsk);
> -
> - if (tsk == current)
> - asm("addik %0, r1, 0" : "=r" (sp));
> - else
> - sp = (unsigned int *)ti->cpu_context.r1;
> -
> - while (!kstack_end(sp)) {
> - addr = *sp++;
> - if (__kernel_text_address(addr)) {
> - if (trace->skip > 0)
> - trace->skip--;
> - else
> - trace->entries[trace->nr_entries++] = addr;
> -
> - if (trace->nr_entries >= trace->max_entries)
> - break;
> - }
> - }
> + microblaze_unwind(tsk, trace);
> }
> EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
> diff -uprN a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c
> --- a/arch/microblaze/kernel/traps.c 2010-04-09 21:52:36.000000000 -0500
> +++ b/arch/microblaze/kernel/traps.c 2010-04-12 22:16:01.000000000 -0500
> @@ -13,16 +13,19 @@
> #include <linux/module.h>
> #include <linux/sched.h>
> #include <linux/debug_locks.h>
> +#include <linux/seq_file.h>
>
> #include <asm/exceptions.h>
> #include <asm/system.h>
>
> +#include "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 +33,42 @@ 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;
> + unsigned long words_to_show;
> + __u32 fp = (__u32) sp;


include/asm-generic/int-ll64.h - just u32 is enough. The same above too.

/*
* __xx is ok: it doesn't pollute the POSIX namespace. Use these in the
* header files exported to user space
*/

>
> - if (!stack)
> - stack = (unsigned long *)&stack;
> + 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;
> + }
> + }

just coding style.

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;

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("Stack:\n");
> + if (fp & 0xF) {
> + unsigned long line1_words = (0x10 - (fp & 0xF)) >> 2;

these constants need some comments.

> + 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 +76,6 @@ void show_trace(struct task_struct *task
> 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);
> @@ -129,3 +115,4 @@ int debug_trap(struct pt_regs *regs)
> return -ENOSYS;
> }
> #endif
> +

remove this white line

I will continue on it tomorrow.

Michal

> diff -uprN a/arch/microblaze/kernel/unwind.c b/arch/microblaze/kernel/unwind.c
> --- a/arch/microblaze/kernel/unwind.c 1969-12-31 18:00:00.000000000 -0600
> +++ b/arch/microblaze/kernel/unwind.c 2010-04-12 22:16:01.000000000 -0500
> @@ -0,0 +1,316 @@
> +/*
> + * Backtrace support for Microblaze
> + *
> + * Copyright (C) 2010 Digital Design Corporation
> + *
> + * Based on arch/sh/kernel/cpu/sh5/unwind.c code which is:
> + * Copyright (C) 2004 Paul Mundt
> + * Copyright (C) 2004 Richard Curnow
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License. See the file "COPYING" in the main directory of this archive
> + * for more details.
> + */
> +
> +/* #define DEBUG 1 */
> +#include <linux/kallsyms.h>
> +#include <linux/kernel.h>
> +#include <linux/sched.h>
> +#include <linux/stacktrace.h>
> +#include <linux/types.h>
> +#include <linux/errno.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <asm/sections.h>
> +#include <asm/exceptions.h>
> +#include "unwind.h"
> +
> +struct stack_trace;
> +
> +/*
> + * On Microblaze, finding the previous stack frame is a little tricky.
> + * At this writing (3/2010), Microblaze does not support CONFIG_FRAME_POINTERS,
> + * and even if it did, gcc (4.1.2) does not store the frame pointer at
> + * a consistent offset within each frame. To determine frame size, it is
> + * necessary to search for the assembly instruction that creates the frame
> + * and extract the size from it.
> + *
> + * Microblaze stores the stack pointer in r1, and creates a frame via
> + *
> + * addik r1, r1, -FRAME_SIZE
> + *
> + * A stack frame is usually not created in a leaf function.
> + *
> + */
> +
> +/**
> + * get_frame_size - Extract the stack adjustment from an
> + * "addik r1, r1, -adjust" instruction
> + * @instr : Microblaze instruction
> + *
> + * Return - Number of bytes the instruction reserves for a stack frame
> + */
> +inline s16 get_frame_size(unsigned long instr)
> +{
> + return -(s16)(instr & 0xFFFF);
> +}
> +
> +/**
> + * find_frame_creation - Search backward to find the instruction that creates
> + * the stack frame (hopefully, for the same function the
> + * initial PC is in).
> + * @pc : Program counter at which to begin the search
> + *
> + * Return - PC at which stack frame creation occurs
> + * NULL if this cannot be found, i.e. a leaf function
> + */
> +static unsigned long *find_frame_creation(unsigned long *pc)
> +{
> + int i;
> +
> + /* NOTE: Distance to search is arbitrary
> + * 250 works well for most things,
> + * 750 picks up things like tcp_recvmsg(),
> + * 1000 needed for fat_fill_super()
> + */
> + for (i = 0; i < 1000; i++, pc--) {
> + unsigned long instr;
> + s16 frame_size;
> +
> + if (!kernel_text_address((unsigned long) pc))
> + return NULL;
> +
> + instr = *pc;
> +
> + /*
> + * rtsd of some sort,
> + * i.e., a return from a previous function?
> + */
> + if ((instr & 0xFFE00000) == 0xb6000000)
> + return NULL;
> +
> + if ((instr & 0xFFFF0000) != 0x30210000) /* addik r1, r1 */
> + continue;
> +
> + frame_size = get_frame_size(instr);
> + if ((frame_size < 8) || (frame_size & 3)) {
> + pr_debug(" Invalid frame size %d at 0x%p\n",
> + frame_size, pc);
> + return NULL;
> + }
> +
> + pr_debug(" Found frame creation at 0x%p, size %d\n", pc,
> + frame_size);
> + return pc;
> + }
> +
> + return NULL;
> +}
> +
> +/**
> + * lookup_prev_stack_frame - Find the stack frame of the previous function.
> + * @fp : Frame (stack) pointer for current function
> + * @pc : Program counter within current function
> + * @leaf_return : r15 value within current function. If the current function
> + * is a leaf, this is the caller's return address.
> + * @pprev_fp : On exit, set to frame (stack) pointer for previous function
> + * @pprev_pc : On exit, set to current function caller's return address
> + *
> + * Return - 0 on success, -EINVAL if the previous frame cannot be found
> + */
> +static int lookup_prev_stack_frame(unsigned long fp, unsigned long pc,
> + unsigned long leaf_return,
> + unsigned long *pprev_fp,
> + unsigned long *pprev_pc)
> +{
> + unsigned long *prologue = NULL;
> +
> + /* _switch_to is a special leaf function */
> + if (pc != (unsigned long) &_switch_to)
> + prologue = find_frame_creation((unsigned long *)pc);
> +
> + if (prologue) {
> + s16 frame_size = get_frame_size(*prologue);
> +
> + *pprev_fp = fp + frame_size;
> + *pprev_pc = *(unsigned long *)fp;
> + } else {
> + if (!leaf_return)
> + return -EINVAL;
> + *pprev_pc = leaf_return;
> + *pprev_fp = fp;
> + }
> +
> + /* NOTE: don't check kernel_text_address here, to allow display
> + * of userland return address
> + */
> + return (!*pprev_pc || (*pprev_pc & 3)) ? -EINVAL : 0;
> +}
> +
> +static void microblaze_unwind_inner(struct task_struct *task,
> + unsigned long pc, unsigned long fp,
> + unsigned long leaf_return,
> + struct stack_trace *trace);
> +
> +/**
> + * unwind_trap - Unwind through a system trap, that stored previous state
> + * on the stack.
> + */
> +#ifdef CONFIG_MMU
> +static inline void unwind_trap(struct task_struct *task, unsigned long pc,
> + unsigned long fp, struct stack_trace *trace)
> +{
> + /* To be implemented */
> +}
> +#else
> +static inline void unwind_trap(struct task_struct *task, unsigned long pc,
> + unsigned long fp, struct stack_trace *trace)
> +{
> + const struct pt_regs *regs = (const struct pt_regs *) fp;
> + microblaze_unwind_inner(task, regs->pc, regs->r1, regs->r15, trace);
> +}
> +#endif
> +
> +/**
> + * microblaze_unwind_inner - Unwind the stack from the specified point
> + * @task : Task whose stack we are to unwind (may be NULL)
> + * @pc : Program counter from which we start unwinding
> + * @fp : Frame (stack) pointer from which we start unwinding
> + * @leaf_return : Value of r15 at pc. If the function is a leaf, this is
> + * the caller's return address.
> + * @trace : Where to store stack backtrace (PC values).
> + * NULL == print backtrace to kernel log
> + */
> +void microblaze_unwind_inner(struct task_struct *task,
> + unsigned long pc, unsigned long fp,
> + unsigned long leaf_return,
> + struct stack_trace *trace)
> +{
> + int ofs = 0;
> +
> + pr_debug(" Unwinding with PC=%p, FP=%p\n", (void *)pc, (void *)fp);
> + if (!pc || !fp || (pc & 3) || (fp & 3)) {
> + pr_debug(" Invalid state for unwind, aborting\n");
> + return;
> + }
> + for (; pc != 0;) {
> + unsigned long next_fp, next_pc = 0;
> + unsigned long return_to = pc + 2 * sizeof(unsigned long);
> + const struct trap_handler_info *handler =
> + &microblaze_trap_handlers;
> +
> + /* Is previous function the HW exception handler? */
> + if ((return_to >= (unsigned long)&_hw_exception_handler)
> + &&(return_to < (unsigned long)&ex_handler_unhandled)) {
> + /*
> + * HW exception handler doesn't save all registers,
> + * so we open-code a special case of unwind_trap()
> + */
> +#ifndef CONFIG_MMU
> + const struct pt_regs *regs =
> + (const struct pt_regs *) fp;
> +#endif
> + pr_info("HW EXCEPTION\n");
> +#ifndef CONFIG_MMU
> + microblaze_unwind_inner(task, regs->r17 - 4,
> + fp + EX_HANDLER_STACK_SIZ,
> + regs->r15, trace);
> +#endif
> + return;
> + }
> +
> + /* Is previous function a trap handler? */
> + for (; handler->start_addr; ++handler) {
> + if ((return_to >= handler->start_addr)
> + && (return_to <= handler->end_addr)) {
> + if (!trace)
> + pr_info("%s\n", handler->trap_name);
> + unwind_trap(task, pc, fp, trace);
> + return;
> + }
> + }
> + pc -= ofs;
> +
> + if (trace) {
> +#ifdef CONFIG_STACKTRACE
> + if (trace->skip > 0)
> + trace->skip--;
> + else
> + trace->entries[trace->nr_entries++] = pc;
> +
> + if (trace->nr_entries >= trace->max_entries)
> + break;
> +#endif
> + } else {
> + /* Have we reached userland? */
> + if (unlikely(pc == task_pt_regs(task)->pc)) {
> + pr_info("[<%p>] PID %lu [%s]\n",
> + (void *) pc,
> + (unsigned long) task->pid,
> + task->comm);
> + break;
> + } else
> + print_ip_sym(pc);
> + }
> +
> + /* Stop when we reach anything not part of the kernel */
> + if (!kernel_text_address(pc))
> + break;
> +
> + if (lookup_prev_stack_frame(fp, pc, leaf_return, &next_fp,
> + &next_pc) == 0) {
> + ofs = sizeof(unsigned long);
> + pc = next_pc & ~3;
> + fp = next_fp;
> + leaf_return = 0;
> + } else {
> + pr_debug(" Failed to find previous stack frame\n");
> + break;
> + }
> +
> + pr_debug(" Next PC=%p, next FP=%p\n",
> + (void *)next_pc, (void *)next_fp);
> + }
> +}
> +
> +/**
> + * microblaze_unwind - Stack unwinder for Microblaze (external entry point)
> + * @task : Task whose stack we are to unwind (NULL == current)
> + * @trace : Where to store stack backtrace (PC values).
> + * NULL == print backtrace to kernel log
> + */
> +void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
> +{
> + if (task) {
> + if (task == current) {
> + const struct pt_regs *regs = task_pt_regs(task);
> + microblaze_unwind_inner(task, regs->pc, regs->r1,
> + regs->r15, trace);
> + } else {
> + struct thread_info *thread_info =
> + (struct thread_info *)(task->stack);
> + const struct cpu_context *cpu_context =
> + &thread_info->cpu_context;
> +
> + microblaze_unwind_inner(task,
> + (unsigned long) &_switch_to,
> + cpu_context->r1,
> + cpu_context->r15, trace);
> + }
> + } else {
> + unsigned long pc, fp;
> +
> + __asm__ __volatile__ ("or %0, r1, r0" : "=r" (fp));
> +
> + __asm__ __volatile__ (
> + "brlid %0, 0f;"
> + "nop;"
> + "0:"
> + : "=r" (pc)
> + );
> +
> + /* Since we are not a leaf function, use leaf_return = 0 */
> + microblaze_unwind_inner(current, pc, fp, 0, trace);
> + }
> +}
> +
> diff -uprN a/arch/microblaze/kernel/unwind.h b/arch/microblaze/kernel/unwind.h
> --- a/arch/microblaze/kernel/unwind.h 1969-12-31 18:00:00.000000000 -0600
> +++ b/arch/microblaze/kernel/unwind.h 2010-04-12 22:16:01.000000000 -0500
> @@ -0,0 +1,29 @@
> +/*
> + * Backtrace support for Microblaze
> + *
> + * Copyright (C) 2010 Digital Design Corporation
> + *
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License. See the file "COPYING" in the main directory of this archive
> + * for more details.
> + */
> +
> +#ifndef __MICROBLAZE_UNWIND_H
> +#define __MICROBLAZE_UNWIND_H
> +
> +struct stack_trace;
> +
> +struct trap_handler_info {
> + unsigned long start_addr;
> + unsigned long end_addr;
> + const char *trap_name;
> +};
> +extern struct trap_handler_info microblaze_trap_handlers;
> +
> +extern const char _hw_exception_handler;
> +extern const char ex_handler_unhandled;
> +
> +void microblaze_unwind(struct task_struct *task, struct stack_trace *trace);
> +
> +#endif /* __MICROBLAZE_UNWIND_H */
> +
>
>


--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian


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