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/*
* arch/ubicom32/kernel/stacktrace.c
* Ubicom32 architecture stack back trace implementation.
*
* (C) Copyright 2009, Ubicom, Inc.
*
* This file is part of the Ubicom32 Linux Kernel Port.
*
* The Ubicom32 Linux Kernel Port is free software: you can redistribute
* it and/or modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, either version 2 of the
* License, or (at your option) any later version.
*
* The Ubicom32 Linux Kernel Port is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the Ubicom32 Linux Kernel Port. If not,
* see <http://www.gnu.org/licenses/>.
*
* Ubicom32 implementation derived from (with many thanks):
* arch/m68knommu
* arch/blackfin
* arch/parisc
*/
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/module.h>
#include <asm/stacktrace.h>
#include <asm/thread.h>
#include <asm/ip5000.h>
/*
* These symbols are filled in by the linker.
*/
extern unsigned long _stext;
extern unsigned long _etext;
extern unsigned long __ocm_text_run_begin;
extern unsigned long __data_begin;
/*
* stacktrace_iterate()
* Walk the stack looking for call and calli instructions on an aligned
* boundary.
*
* Trace must point to the top of the current stack frame.
*/
unsigned long stacktrace_iterate(unsigned long **trace,
unsigned long stext,
unsigned long etext,
unsigned long ocm_stext,
unsigned long ocm_etext,
unsigned long sstack,
unsigned long estack)
{
unsigned int thread_trap_en, instruction;
unsigned long address;
unsigned int limit = 0;
unsigned long result = 0;
unsigned long *sp = *trace;
/*
* Exclude the current thread from being monitored for traps.
*/
asm volatile(
" thread_get_self_mask d15 \n\t"
/* save current trap status */
" and.4 %0, MT_TRAP_EN, d15 \n\t"
" not.4 d15, d15 \n\t"
/* disable trap */
" and.4 MT_TRAP_EN, MT_TRAP_EN, d15 \n\t"
" pipe_flush 0 \n\t"
: "=r" (thread_trap_en)
:
: "d15", "cc"
);
while (limit++ < 256) {
/*
* See if we have a valid stack.
*/
if (!between((unsigned long)sp, sstack, estack)) {
#ifdef TRAP_DEBUG_STACK_TRACE
printk(KERN_EMERG "stack address is out of range - "
"sp: %x, sstack: %x, estack: %x\n",
(unsigned int)sp, (unsigned int)sstack,
(unsigned int)estack);
#endif
result = 0;
*trace = 0;
break;
}
/*
* Get the value off the stack and back up 4 bytes to what
* should be the address of a call or calli.
*/
address = (*sp++) - 4;
/*
* If the address is not within the text segment, skip this
* value.
*/
if (!between(address, stext, etext) &&
!between(address, ocm_stext, ocm_etext)) {
#ifdef TRAP_DEBUG_STACK_TRACE
printk(KERN_EMERG "not a text address - "
"address: %08x, stext: %08x, etext: %08x\n"
"ocm_stext: %08x, ocm_etext: %08x\n",
(unsigned int)address,
(unsigned int)stext,
(unsigned int)etext,
(unsigned int)ocm_stext,
(unsigned int)ocm_etext);
#endif
continue;
}
/*
* If the address is not on an aligned boundary it can not be a
* return address.
*/
if (address & 0x3) {
continue;
}
/*
* Read the probable instruction.
*/
instruction = *(unsigned int *)address;
/*
* Is this a call instruction?
*/
if ((instruction & 0xF8000000) == (u32_t)(0x1B << 27)) {
#ifdef TRAP_DEBUG_STACK_TRACE
printk(KERN_EMERG "call inst. result: %x, "
"test: %x\n", (unsigned int)address,
(unsigned int)instruction);
#endif
*trace = sp;
result = address;
break;
}
/*
* Is this a calli instruction?
*/
if ((instruction & 0xF8000000) == (u32_t)(0x1E << 27)) {
#ifdef TRAP_DEBUG_STACK_TRACE
printk(KERN_EMERG "calli inst. result: %x, "
"test: %x\n", (unsigned int)address,
(unsigned int)instruction);
#endif
*trace = sp;
result = address;
break;
}
}
/*
* Restore the current thread to be monitored for traps.
*/
if (thread_trap_en) {
asm volatile(
" thread_get_self_mask d15 \n\t"
" or.4 MT_TRAP_EN, MT_TRAP_EN, d15 \n\t"
:
:
: "d15", "cc"
);
}
return result;
}
#ifdef CONFIG_STACKTRACE
/*
* stacktrace_save_entries()
* Save stack back trace information into the provided trace structure.
*/
void stacktrace_save_entries(struct task_struct *tsk,
struct stack_trace *trace,
unsigned long sp)
{
unsigned long code_start = (unsigned long)&_stext;
unsigned long code_end = (unsigned long)&_etext;
unsigned long ocm_code_start = (unsigned long)&__ocm_text_run_begin;
unsigned long ocm_code_end = (unsigned long)&__data_begin;
unsigned long stack_end = (unsigned long)(tsk->stack + THREAD_SIZE - 8);
unsigned long stack = (unsigned long)sp;
unsigned int idx = 0;
unsigned long *handle;
int skip = trace->skip;
handle = (unsigned long *)stack;
while (idx < trace->max_entries) {
if (skip) {
skip--;
continue;
}
trace->entries[idx] = stacktrace_iterate(&handle,
code_start, code_end,
ocm_code_start, ocm_code_end,
(unsigned long)stack, stack_end);
if (trace->entries[idx] == 0) {
break;
}
idx++;
}
}
/*
* save_stack_trace()
* Save the specified amount of the kernel stack trace information
* for the current task.
*/
void save_stack_trace(struct stack_trace *trace)
{
unsigned long sp = 0;
asm volatile (
" move.4 %0, SP \n\t"
: "=r" (sp)
);
stacktrace_save_entries(current, trace, sp);
}
EXPORT_SYMBOL_GPL(save_stack_trace);
/*
* save_stack_trace_tsk()
* Save the specified amount of the kernel stack trace information
* for the specified task.
*
* Note: We assume the specified task is not currently running.
*/
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
stacktrace_save_entries(tsk, trace, tsk->thread.sp);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
#endif /* CONFIG_STACKTRACE */
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