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/*
* Stack trace management functions
*
* Copyright IBM Corp. 2006
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/kallsyms.h>
#include <linux/module.h>
static unsigned long save_context_stack(struct stack_trace *trace,
unsigned long sp,
unsigned long low,
unsigned long high,
int savesched)
{
struct stack_frame *sf;
struct pt_regs *regs;
unsigned long addr;
while(1) {
if (sp < low || sp > high)
return sp;
sf = (struct stack_frame *)sp;
while(1) {
addr = sf->gprs[8];
if (!trace->skip)
trace->entries[trace->nr_entries++] = addr;
else
trace->skip--;
if (trace->nr_entries >= trace->max_entries)
return sp;
low = sp;
sp = sf->back_chain;
if (!sp)
break;
if (sp <= low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *)sp;
}
/* Zero backchain detected, check for interrupt frame. */
sp = (unsigned long)(sf + 1);
if (sp <= low || sp > high - sizeof(*regs))
return sp;
regs = (struct pt_regs *)sp;
addr = regs->psw.addr;
if (savesched || !in_sched_functions(addr)) {
if (!trace->skip)
trace->entries[trace->nr_entries++] = addr;
else
trace->skip--;
}
if (trace->nr_entries >= trace->max_entries)
return sp;
low = sp;
sp = regs->gprs[15];
}
}
void save_stack_trace(struct stack_trace *trace)
{
register unsigned long sp asm ("15");
unsigned long orig_sp, new_sp, frame_size;
frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
orig_sp = sp;
new_sp = save_context_stack(trace, orig_sp,
S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
S390_lowcore.panic_stack + frame_size, 1);
if (new_sp != orig_sp)
return;
new_sp = save_context_stack(trace, new_sp,
S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
S390_lowcore.async_stack + frame_size, 1);
if (new_sp != orig_sp)
return;
save_context_stack(trace, new_sp,
S390_lowcore.thread_info,
S390_lowcore.thread_info + THREAD_SIZE, 1);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
unsigned long sp, low, high;
sp = tsk->thread.ksp;
if (tsk == current) {
/* Get current stack pointer. */
asm volatile("la %0,0(15)" : "=a" (sp));
}
low = (unsigned long) task_stack_page(tsk);
high = (unsigned long) task_pt_regs(tsk);
save_context_stack(trace, sp, low, high, 0);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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