void tile_backtrace(struct pt_regs *const regs, unsigned int depth)
{
struct KBacktraceIterator kbt;
unsigned int i;
/*
* Get the address just after the "jalr" instruction that
* jumps to the handler for a syscall. When we find this
* address in a backtrace, we silently ignore it, which gives
* us a one-step backtrace connection from the sys_xxx()
* function in the kernel to the xxx() function in libc.
* Otherwise, we lose the ability to properly attribute time
* from the libc calls to the kernel implementations, since
* oprofile only considers PCs from backtraces a pair at a time.
*/
unsigned long handle_syscall_pc = handle_syscall_link_address();
KBacktraceIterator_init(&kbt, NULL, regs);
kbt.profile = 1;
/*
* The sample for the pc is already recorded. Now we are adding the
* address of the callsites on the stack. Our iterator starts
* with the frame of the (already sampled) call site. If our
* iterator contained a "return address" field, we could have just
* used it and wouldn't have needed to skip the first
* frame. That's in effect what the arm and x86 versions do.
* Instead we peel off the first iteration to get the equivalent
* behavior.
*/
if (KBacktraceIterator_end(&kbt))
return;
KBacktraceIterator_next(&kbt);
for (i = 0; i < depth; ++i) {
int is_kernel;
unsigned long pc;
if (KBacktraceIterator_end(&kbt))
break;
pc = kbt.it.pc;
is_kernel = (pc >= PAGE_OFFSET &&
!is_arch_mappable_range(pc, 1));
if (pc != handle_syscall_pc)
oprofile_add_pc(pc, is_kernel, 0);
KBacktraceIterator_next(&kbt);
}
}
/*
* This method wraps the backtracer's more generic support.
* It is only invoked from the architecture-specific code; show_stack()
* and dump_stack() (in entry.S) are architecture-independent entry points.
*/
void tile_show_stack(struct KBacktraceIterator *kbt, int headers)
{
int i;
if (headers) {
/*
* Add a blank line since if we are called from panic(),
* then bust_spinlocks() spit out a space in front of us
* and it will mess up our KERN_ERR.
*/
pr_err("\n");
pr_err("Starting stack dump of tid %d, pid %d (%s)"
" on cpu %d at cycle %lld\n",
kbt->task->pid, kbt->task->tgid, kbt->task->comm,
smp_processor_id(), get_cycles());
}
kbt->verbose = 1;
i = 0;
for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) {
char *modname;
const char *name;
unsigned long address = kbt->it.pc;
unsigned long offset, size;
char namebuf[KSYM_NAME_LEN+100];
if (address >= PAGE_OFFSET)
name = kallsyms_lookup(address, &size, &offset,
&modname, namebuf);
else
name = NULL;
if (!name)
namebuf[0] = '\0';
else {
size_t namelen = strlen(namebuf);
size_t remaining = (sizeof(namebuf) - 1) - namelen;
char *p = namebuf + namelen;
int rc = snprintf(p, remaining, "+%#lx/%#lx ",
offset, size);
if (modname && rc < remaining)
snprintf(p + rc, remaining - rc,
"[%s] ", modname);
namebuf[sizeof(namebuf)-1] = '\0';
}
pr_err(" frame %d: 0x%lx %s(sp 0x%lx)\n",
i++, address, namebuf, (unsigned long)(kbt->it.sp));
if (i >= 100) {
pr_err("Stack dump truncated"
" (%d frames)\n", i);
break;
}
}
if (kbt->end == KBT_LOOP)
pr_err("Stack dump stopped; next frame identical to this one\n");
if (headers)
pr_err("Stack dump complete\n");
}
void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
{
struct KBacktraceIterator kbt;
int skip = trace->skip;
int i = 0;
if (task == NULL || task == current)
KBacktraceIterator_init_current(&kbt);
else
KBacktraceIterator_init(&kbt, task, NULL);
for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) {
if (skip) {
--skip;
continue;
}
if (i >= trace->max_entries || kbt.it.pc < PAGE_OFFSET)
break;
trace->entries[i++] = kbt.it.pc;
}
trace->nr_entries = i;
}
