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Use kernel builtin tracer instead of copying everything ourselves.

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2008-03-20  Soren Sandmann <sandmann@redhat.com>
 
       * module/sysprof-module.c (trace_kernel): Use kernel builtin
       tracer instead of copying everything ourselves.


svn path=/trunk/; revision=401
This commit is contained in:
Soren Sandmann
2008-03-20 09:49:46 +00:00
committed by Søren Sandmann Pedersen
parent 83fd2bbc31
commit c2de993836
5 changed files with 107 additions and 31 deletions
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99
module/sysprof-module.c
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@ -30,6 +30,7 @@
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <asm/stacktrace.h>
#include <linux/poll.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
@ -151,40 +152,84 @@ nt_memcpy (void *dst, void *src, int n_bytes)
#endif
}
static struct pt_regs *
copy_kernel_stack (struct pt_regs *regs,
SysprofStackTrace *trace)
/*
* The functions backtrace_* are based on oprofile's backtrace.c
*
* @remark Copyright 2002 OProfile authors
* @remark Read the file COPYING
*
* @author John Levon
* @author David Smith
*/
static void backtrace_warning_symbol(void *data, char *msg,
unsigned long symbol)
{
int n_bytes;
char *esp;
/* Ignore warnings */
}
static void backtrace_warning(void *data, char *msg)
{
/* Ignore warnings */
}
struct backtrace_info_t
{
SysprofStackTrace *trace;
int pos;
};
static int backtrace_stack(void *data, char *name)
{
/* Don't bother with IRQ stacks for now */
return -1;
}
static void backtrace_address(void *data, unsigned long addr, int reliable)
{
struct backtrace_info_t *info = data;
if (info->pos < SYSPROF_MAX_ADDRESSES && reliable)
info->trace->kernel_stack[info->pos++] = (void *)addr;
}
const static struct stacktrace_ops backtrace_ops = {
.warning = backtrace_warning,
.warning_symbol = backtrace_warning_symbol,
.stack = backtrace_stack,
.address = backtrace_address,
};
static struct pt_regs *
trace_kernel (struct pt_regs *regs,
SysprofStackTrace *trace)
{
struct backtrace_info_t info;
char *eos;
unsigned long stack;
unsigned long bp;
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.
info.trace = trace;
info.pos = 1;
stack = (unsigned long) ((char *)regs + sizeof (struct pt_regs));
#ifdef CONFIG_FRAME_POINTER
/* We can't set it to 0, because then the stack trace will
* contain the stack of the timer interrupt
*/
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) {
#if 0
nt_memcpy (&(trace->kernel_stack[1]), esp, n_bytes);
bp = regs->REG_FRAME_PTR;
#else
bp = 0;
#endif
memcpy (&(trace->kernel_stack[1]), esp, n_bytes);
trace->n_kernel_words += (n_bytes) / sizeof (void *);
}
dump_trace(NULL, regs, stack, bp, &backtrace_ops, &info);
trace->n_kernel_words = info.pos;
/* Now trace the user stack */
eos = (char *)current->thread.REG_STACK_PTR0 - sizeof (struct pt_regs);
return (struct pt_regs *)eos;
}
@ -318,7 +363,7 @@ timer_notify (struct pt_regs *regs)
trace->n_addresses = 0;
if (!is_user)
regs = copy_kernel_stack (regs, trace);
regs = trace_kernel (regs, trace);
trace->addresses[0] = (void *)regs->REG_INS_PTR;
trace->n_addresses = 1;