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#ifndef _STACK_C_ /* -*- linux-c -*- */
#define _STACK_C_
/** @file stack.c
* @brief Stack Tracing Functions
*/
/** @addtogroup stack Stack Tracing Functions
* @{
*/
#include "sym.c"
static int (*_stp_kta)(unsigned long addr)=(void *)KTA;
struct frame_head {
struct frame_head * ebp;
unsigned long ret;
} __attribute__((packed));
static struct frame_head *
dump_backtrace(struct frame_head * head)
{
_stp_printf ("db: %lx\n", head->ret);
/* frame pointers should strictly progress back up the stack
* (towards higher addresses) */
if (head >= head->ebp)
return NULL;
return head->ebp;
}
static int pages_present(struct frame_head * head)
{
struct mm_struct * mm = current->mm;
/* FIXME: only necessary once per page */
if (!check_user_page_readable(mm, (unsigned long)head))
return 0;
return check_user_page_readable(mm, (unsigned long)(head + 1));
}
static int valid_kernel_stack(struct frame_head * head, struct pt_regs * regs)
{
unsigned long headaddr = (unsigned long)head;
unsigned long stack = (unsigned long)regs;
unsigned long stack_base = (stack & ~(THREAD_SIZE - 1)) + THREAD_SIZE;
_stp_log ("%lx %lx %lx\n", headaddr, stack, stack_base);
return headaddr < stack_base;
}
void
x86_backtrace(struct pt_regs * const regs, unsigned int depth)
{
struct frame_head *head;
#ifdef CONFIG_X86_64
head = (struct frame_head *)regs->rbp;
#else
head = (struct frame_head *)regs->ebp;
#endif
if (!user_mode(regs)) {
_stp_log ("kernel mode\n");
while (depth-- && valid_kernel_stack(head, regs))
head = dump_backtrace(head);
_stp_print_flush();
return;
}
#ifdef CONFIG_SMP
if (!spin_trylock(¤t->mm->page_table_lock))
return;
#endif
while (depth-- && head && pages_present(head))
head = dump_backtrace(head);
#ifdef CONFIG_SMP
spin_unlock(¤t->mm->page_table_lock);
#endif
_stp_print_flush();
}
#ifdef __x86_64__
static void __stp_stack_print (unsigned long *stack, int verbose, int levels)
{
unsigned long addr;
while (((long) stack & (THREAD_SIZE-1)) != 0) {
addr = *stack;
if (_stp_kta(addr)) {
if (verbose) {
_stp_symbol_print (addr);
_stp_print ("\n");
} else
_stp_printf ("0x%lx ", addr);
}
stack++;
}
_stp_print_flush();
}
static void __stp_stack_sprint (String str, unsigned long *stack, int verbose, int levels)
{
unsigned long addr;
while (((long) stack & (THREAD_SIZE-1)) != 0) {
addr = *stack++;
if (_stp_kta(addr)) {
if (verbose) {
_stp_symbol_sprint (str, addr);
_stp_sprintf (str, "\n");
} else
_stp_sprintf (str, "0x%lx\n", addr);
}
}
}
#else /* i386 */
static inline int valid_stack_ptr (struct thread_info *tinfo, void *p)
{
return p > (void *)tinfo &&
p < (void *)tinfo + THREAD_SIZE - 3;
}
static inline unsigned long _stp_print_context_stack (
struct thread_info *tinfo,
unsigned long *stack,
unsigned long ebp )
{
unsigned long addr;
#ifdef CONFIG_FRAME_POINTER
while (valid_stack_ptr(tinfo, (void *)ebp)) {
addr = *(unsigned long *)(ebp + 4);
_stp_symbol_print (addr);
_stp_print_cstr("\n");
ebp = *(unsigned long *)ebp;
}
#else
while (valid_stack_ptr(tinfo, stack)) {
addr = *stack++;
if (_stp_kta (addr)) {
_stp_symbol_print (addr);
_stp_print_cstr ("\n");
}
}
#endif
_stp_print_flush();
return ebp;
}
static inline unsigned long _stp_sprint_context_stack (
String str,
struct thread_info *tinfo,
unsigned long *stack,
unsigned long ebp )
{
unsigned long addr;
#ifdef CONFIG_FRAME_POINTER
while (valid_stack_ptr(tinfo, (void *)ebp)) {
addr = *(unsigned long *)(ebp + 4);
_stp_symbol_sprint (str, addr);
_stp_string_cat (str, "\n");
ebp = *(unsigned long *)ebp;
}
#else
while (valid_stack_ptr(tinfo, stack)) {
addr = *stack++;
if (_stp_kta (addr)) {
_stp_symbol_sprint (str, addr);
_stp_string_cat (str, "\n");
}
}
#endif
return ebp;
}
static void __stp_stack_print (unsigned long *stack, int verbose, int levels)
{
unsigned long ebp;
/* Grab ebp right from our regs */
asm ("movl %%ebp, %0" : "=r" (ebp) : );
while (stack) {
struct thread_info *context = (struct thread_info *)
((unsigned long)stack & (~(THREAD_SIZE - 1)));
ebp = _stp_print_context_stack (context, stack, ebp);
stack = (unsigned long*)context->previous_esp;
}
_stp_print_flush ();
}
static void __stp_stack_sprint (String str, unsigned long *stack, int verbose, int levels)
{
unsigned long ebp;
/* Grab ebp right from our regs */
asm ("movl %%ebp, %0" : "=r" (ebp) : );
while (stack) {
struct thread_info *context = (struct thread_info *)
((unsigned long)stack & (~(THREAD_SIZE - 1)));
ebp = _stp_sprint_context_stack (str, context, stack, ebp);
stack = (unsigned long*)context->previous_esp;
}
}
#endif /* i386 */
/** Print stack dump.
* Prints a stack dump to the print buffer.
* @param verbose Verbosity
* @param levels Number of levels to trace.
* @todo Implement verbosity and levels parameters.
* @bug levels parameter is not functional
*/
void _stp_stack_jprint (int verbose, int levels)
{
unsigned long stack;
__stp_stack_print (&stack, verbose, levels);
}
void _stp_stack_print (struct pt_regs *regs, int verbose, int levels)
{
if (verbose) {
_stp_printf ("trace for %d (%s)\n", current->pid, current->comm);
_stp_symbol_print (regs->rip);
_stp_print ("\n");
} else
_stp_printf ("0x%lx ", regs->rip);
__stp_stack_print ((unsigned long *)regs->rsp, verbose, levels);
}
/** Writes stack dump to a String
*
* @param str String
* @param verbose Verbosity
* @param levels Number of levels to trace.
* @returns Same String as was input.
* @todo Implement verbosity and levels parameters.
* @bug levels parameter is not functional
*/
String _stp_stack_sprint (String str, int verbose, int levels)
{
unsigned long stack;
__stp_stack_sprint (str, &stack, verbose, levels);
return str;
}
/** @} */
#endif /* _STACK_C_ */
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