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linux-xiaomi-chiron/arch/s390/kernel/dumpstack.c
Heiko Carstens 758d39ebd3 s390/dumpstack: merge all four stack tracers 
We have four different stack tracers of which three had bugs. So it's
time to merge them to a single stack tracer which allows to specify a
call back function which will be called for each step.

This patch changes behavior a bit:

- the "nosched" and "in_sched_functions" check within
  save_stack_trace_tsk did work only for the last stack frame within a
  context. Now it considers the check for each stack frame like it
  should.

- both the oprofile variant and the perf_events variant did save a
  return address twice if a zero back chain was detected, which
  indicates an interrupt frame. The new dump_trace function will call
  the oprofile and perf_events backends with the psw address that is
  contained within the corresponding pt_regs structure instead.

- the original show_trace and save_context_stack functions did already
  use the psw address of the pt_regs structure if a zero back chain
  was detected. However now we ignore the psw address if it is a user
  space address. After all we trace the kernel stack and not the user
  space stack. This way we also get rid of the garbage user space
  address in case of warnings and / or panic call traces.

So this should make life easier since now there is only one stack
tracer left which we can break.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2016-02-23 08:56:20 +01:00

208 lines
5.6 KiB
C
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/*
* Stack dumping functions
*
* Copyright IBM Corp. 1999, 2013
*/
#include <linux/kallsyms.h>
#include <linux/hardirq.h>
#include <linux/kprobes.h>
#include <linux/utsname.h>
#include <linux/export.h>
#include <linux/kdebug.h>
#include <linux/ptrace.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <asm/processor.h>
#include <asm/debug.h>
#include <asm/dis.h>
#include <asm/ipl.h>
/*
* For dump_trace we have tree different stack to consider:
* - the panic stack which is used if the kernel stack has overflown
* - the asynchronous interrupt stack (cpu related)
* - the synchronous kernel stack (process related)
* The stack trace can start at any of the three stacks and can potentially
* touch all of them. The order is: panic stack, async stack, sync stack.
*/
static unsigned long
__dump_trace(dump_trace_func_t func, void *data, unsigned long sp,
unsigned long low, unsigned long high)
{
struct stack_frame *sf;
struct pt_regs *regs;
while (1) {
if (sp < low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
/* Follow the backchain. */
while (1) {
if (func(data, sf->gprs[8]))
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;
if (!user_mode(regs)) {
if (func(data, regs->psw.addr))
return sp;
}
low = sp;
sp = regs->gprs[15];
}
}
void dump_trace(dump_trace_func_t func, void *data, struct task_struct *task,
unsigned long sp)
{
unsigned long frame_size;
frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
#ifdef CONFIG_CHECK_STACK
sp = __dump_trace(func, data, sp,
S390_lowcore.panic_stack + frame_size - 4096,
S390_lowcore.panic_stack + frame_size);
#endif
sp = __dump_trace(func, data, sp,
S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
S390_lowcore.async_stack + frame_size);
if (task)
__dump_trace(func, data, sp,
(unsigned long)task_stack_page(task),
(unsigned long)task_stack_page(task) + THREAD_SIZE);
else
__dump_trace(func, data, sp,
S390_lowcore.thread_info,
S390_lowcore.thread_info + THREAD_SIZE);
}
EXPORT_SYMBOL_GPL(dump_trace);
static int show_address(void *data, unsigned long address)
{
printk("([<%016lx>] %pSR)\n", address, (void *)address);
return 0;
}
static void show_trace(struct task_struct *task, unsigned long sp)
{
if (!sp)
sp = task ? task->thread.ksp : current_stack_pointer();
printk("Call Trace:\n");
dump_trace(show_address, NULL, task, sp);
if (!task)
task = current;
debug_show_held_locks(task);
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
unsigned long *stack;
int i;
stack = sp;
if (!stack) {
if (!task)
stack = (unsigned long *)current_stack_pointer();
else
stack = (unsigned long *)task->thread.ksp;
}
for (i = 0; i < 20; i++) {
if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
break;
if ((i * sizeof(long) % 32) == 0)
printk("%s ", i == 0 ? "" : "\n");
printk("%016lx ", *stack++);
}
printk("\n");
show_trace(task, (unsigned long)sp);
}
static void show_last_breaking_event(struct pt_regs *regs)
{
printk("Last Breaking-Event-Address:\n");
printk(" [<%016lx>] %pSR\n", regs->args[0], (void *)regs->args[0]);
}
void show_registers(struct pt_regs *regs)
{
struct psw_bits *psw = &psw_bits(regs->psw);
char *mode;
mode = user_mode(regs) ? "User" : "Krnl";
printk("%s PSW : %p %p", mode, (void *)regs->psw.mask, (void *)regs->psw.addr);
if (!user_mode(regs))
printk(" (%pSR)", (void *)regs->psw.addr);
printk("\n");
printk(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
"P:%x AS:%x CC:%x PM:%x", psw->r, psw->t, psw->i, psw->e,
psw->key, psw->m, psw->w, psw->p, psw->as, psw->cc, psw->pm);
printk(" RI:%x EA:%x", psw->ri, psw->eaba);
printk("\n%s GPRS: %016lx %016lx %016lx %016lx\n", mode,
regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
printk(" %016lx %016lx %016lx %016lx\n",
regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
printk(" %016lx %016lx %016lx %016lx\n",
regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
printk(" %016lx %016lx %016lx %016lx\n",
regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
show_code(regs);
}
void show_regs(struct pt_regs *regs)
{
show_regs_print_info(KERN_DEFAULT);
show_registers(regs);
/* Show stack backtrace if pt_regs is from kernel mode */
if (!user_mode(regs))
show_trace(NULL, regs->gprs[15]);
show_last_breaking_event(regs);
}
static DEFINE_SPINLOCK(die_lock);
void die(struct pt_regs *regs, const char *str)
{
static int die_counter;
oops_enter();
lgr_info_log();
debug_stop_all();
console_verbose();
spin_lock_irq(&die_lock);
bust_spinlocks(1);
printk("%s: %04x ilc:%d [#%d] ", str, regs->int_code & 0xffff,
regs->int_code >> 17, ++die_counter);
#ifdef CONFIG_PREEMPT
printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
printk("DEBUG_PAGEALLOC");
#endif
printk("\n");
notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
print_modules();
show_regs(regs);
bust_spinlocks(0);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
spin_unlock_irq(&die_lock);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception: panic_on_oops");
oops_exit();
do_exit(SIGSEGV);
}
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