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Crude heuristic stack scanning on x86-64.

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Sun Nov 18 18:12:09 2007  Søren Sandmann  <sandmann@redhat.com>

       * module/sysprof-module.c (heuristic_trace): Crude heuristic stack
       scanning on x86-64.

       * module/sysprof-module.c (copy_kernel_stack): New function



svn path=/trunk/; revision=392
This commit is contained in:
Søren Sandmann
2007-11-18 23:11:52 +00:00
committed by Søren Sandmann Pedersen
parent a68837a3ad
commit 05c4a202b3
2 changed files with 74 additions and 39 deletions
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106
module/sysprof-module.c
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@ -112,6 +112,40 @@ minimum (int a, int b)
return a > b ? b : a;
}
static struct pt_regs *
copy_kernel_stack (struct pt_regs *regs,
SysprofStackTrace *trace)
{
int n_bytes;
char *esp;
char *eos;
trace->kernel_stack[0] = (void *)regs->REG_INS_PTR;
trace->n_kernel_words = 1;
/* The timer interrupt happened in kernel mode. When this
* happens the registers are pushed on the stack, _except_
* esp. So we can't use regs->esp to copy the stack pointer.
* Instead we use the fact that the regs pointer itself
* points to the stack.
*/
esp = (char *)regs + sizeof (struct pt_regs);
eos = (char *)current->thread.REG_STACK_PTR0 -
sizeof (struct pt_regs);
n_bytes = minimum ((char *)eos - esp,
sizeof (trace->kernel_stack));
if (n_bytes > 0) {
memcpy (&(trace->kernel_stack[1]), esp, n_bytes);
trace->n_kernel_words += (n_bytes) / sizeof (void *);
}
/* Now trace the user stack */
return (struct pt_regs *)eos;
}
static void
framepointer_trace (struct pt_regs *regs, SysprofStackTrace *trace)
{
@ -119,10 +153,8 @@ framepointer_trace (struct pt_regs *regs, SysprofStackTrace *trace)
int i;
StackFrame frame;
i = 0;
i = 1;
trace->addresses[i++] = (void *)regs->REG_INS_PTR;
framepointer = (void *)regs->REG_FRAME_PTR;
while (read_frame (framepointer, &frame) == 0 &&
@ -140,7 +172,29 @@ static void
heuristic_trace (struct pt_regs *regs,
SysprofStackTrace *trace)
{
return framepointer_trace (regs, trace);
unsigned long esp = regs->REG_STACK_PTR;
unsigned long eos = current->mm->start_stack;
if (esp < eos - (current->mm->stack_vm << PAGE_SHIFT)) {
/* Stack pointer is not in stack map */
return;
}
if (eos > esp) {
unsigned long i;
int j;
j = 1;
for (i = esp; i < eos && j < SYSPROF_MAX_ADDRESSES; i += sizeof (void *)) {
void *x;
if (__copy_from_user_inatomic (
&x, (char *)i, sizeof (x)) == 0)
trace->addresses[j++] = x;
}
trace->n_addresses = j;
}
}
#ifdef OLD_PROFILE
@ -154,7 +208,6 @@ timer_notify (struct pt_regs *regs)
struct pt_regs * regs = (struct pt_regs *)data;
#endif
SysprofStackTrace *trace = &(area->traces[area->head]);
int i;
int is_user;
static atomic_t in_timer_notify = ATOMIC_INIT(1);
int n;
@ -171,7 +224,7 @@ timer_notify (struct pt_regs *regs)
is_user = user_mode(regs);
if (!current || current->pid == 0 || !current->mm)
if (!current || current->pid == 0)
goto out;
if (is_user && current->state != TASK_RUNNING)
@ -184,45 +237,20 @@ timer_notify (struct pt_regs *regs)
trace->n_kernel_words = 0;
trace->n_addresses = 0;
i = 0;
if (!is_user)
{
int n_bytes;
char *esp;
char *eos;
regs = copy_kernel_stack (regs, trace);
trace->kernel_stack[0] = (void *)regs->REG_INS_PTR;
trace->n_kernel_words = 1;
/* The timer interrupt happened in kernel mode. When this
* happens the registers are pushed on the stack, _except_
* esp. So we can't use regs->esp to copy the stack pointer.
* Instead we use the fact that the regs pointer itself
* points to the stack.
*/
esp = (char *)regs + sizeof (struct pt_regs);
eos = (char *)current->thread.REG_STACK_PTR0 -
sizeof (struct pt_regs);
n_bytes = minimum ((char *)eos - esp,
sizeof (trace->kernel_stack));
if (n_bytes > 0) {
memcpy (&(trace->kernel_stack[1]), esp, n_bytes);
trace->n_kernel_words += (n_bytes) / sizeof (void *);
}
/* Now trace the user stack */
regs = (struct pt_regs *)eos;
}
trace->addresses[0] = (void *)regs->REG_INS_PTR;
trace->n_addresses = 1;
if (current->mm) {
#ifdef CONFIG_X86_64
heuristic_trace (regs, trace);
heuristic_trace (regs, trace);
#elif CONFIG_X86
framepointer_trace (regs, trace);
framepointer_trace (regs, trace);
#endif
}
if (trace->n_addresses == SYSPROF_MAX_ADDRESSES)
trace->truncated = 1;
else