Release 4.18 arch/powerpc/kernel/stacktrace.c
// SPDX-License-Identifier: GPL-2.0
/*
* Stack trace utility functions etc.
*
* Copyright 2008 Christoph Hellwig, IBM Corp.
* Copyright 2018 SUSE Linux GmbH
* Copyright 2018 Nick Piggin, Michael Ellerman, IBM Corp.
*/
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/stacktrace.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <linux/ftrace.h>
#include <asm/kprobes.h>
#include <asm/paca.h>
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
static void save_context_stack(struct stack_trace *trace, unsigned long sp,
struct task_struct *tsk, int savesched)
{
for (;;) {
unsigned long *stack = (unsigned long *) sp;
unsigned long newsp, ip;
if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
return;
newsp = stack[0];
ip = stack[STACK_FRAME_LR_SAVE];
if (savesched || !in_sched_functions(ip)) {
if (!trace->skip)
trace->entries[trace->nr_entries++] = ip;
else
trace->skip--;
}
if (trace->nr_entries >= trace->max_entries)
return;
sp = newsp;
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christoph Hellwig | 101 | 79.53% | 1 | 50.00% |
| Arnd Bergmann | 26 | 20.47% | 1 | 50.00% |
| Total | 127 | 100.00% | 2 | 100.00% |
void save_stack_trace(struct stack_trace *trace)
{
unsigned long sp;
sp = current_stack_pointer();
save_context_stack(trace, sp, current, 1);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arnd Bergmann | 25 | 83.33% | 1 | 33.33% |
| Anton Blanchard | 5 | 16.67% | 2 | 66.67% |
| Total | 30 | 100.00% | 3 | 100.00% |
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
unsigned long sp;
if (tsk == current)
sp = current_stack_pointer();
else
sp = tsk->thread.ksp;
save_context_stack(trace, sp, tsk, 0);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Arnd Bergmann | 26 | 52.00% | 2 | 66.67% |
| Thadeu Lima de Souza Cascardo | 24 | 48.00% | 1 | 33.33% |
| Total | 50 | 100.00% | 3 | 100.00% |
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
save_context_stack(trace, regs->gpr[1], current, 0);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Steven Rostedt | 31 | 100.00% | 1 | 100.00% |
| Total | 31 | 100.00% | 1 | 100.00% |
EXPORT_SYMBOL_GPL(save_stack_trace_regs);
#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
int
save_stack_trace_tsk_reliable(struct task_struct *tsk,
struct stack_trace *trace)
{
unsigned long sp;
unsigned long stack_page = (unsigned long)task_stack_page(tsk);
unsigned long stack_end;
int graph_idx = 0;
/*
* The last frame (unwinding first) may not yet have saved
* its LR onto the stack.
*/
int firstframe = 1;
if (tsk == current)
sp = current_stack_pointer();
else
sp = tsk->thread.ksp;
stack_end = stack_page + THREAD_SIZE;
if (!is_idle_task(tsk)) {
/*
* For user tasks, this is the SP value loaded on
* kernel entry, see "PACAKSAVE(r13)" in _switch() and
* system_call_common()/EXCEPTION_PROLOG_COMMON().
*
* Likewise for non-swapper kernel threads,
* this also happens to be the top of the stack
* as setup by copy_thread().
*
* Note that stack backlinks are not properly setup by
* copy_thread() and thus, a forked task() will have
* an unreliable stack trace until it's been
* _switch()'ed to for the first time.
*/
stack_end -= STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
} else {
/*
* idle tasks have a custom stack layout,
* c.f. cpu_idle_thread_init().
*/
stack_end -= STACK_FRAME_OVERHEAD;
}
if (sp < stack_page + sizeof(struct thread_struct) ||
sp > stack_end - STACK_FRAME_MIN_SIZE) {
return 1;
}
for (;;) {
unsigned long *stack = (unsigned long *) sp;
unsigned long newsp, ip;
/* sanity check: ABI requires SP to be aligned 16 bytes. */
if (sp & 0xF)
return 1;
/* Mark stacktraces with exception frames as unreliable. */
if (sp <= stack_end - STACK_INT_FRAME_SIZE &&
stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
return 1;
}
newsp = stack[0];
/* Stack grows downwards; unwinder may only go up. */
if (newsp <= sp)
return 1;
if (newsp != stack_end &&
newsp > stack_end - STACK_FRAME_MIN_SIZE) {
return 1; /* invalid backlink, too far up. */
}
/* Examine the saved LR: it must point into kernel code. */
ip = stack[STACK_FRAME_LR_SAVE];
if (!firstframe && !__kernel_text_address(ip))
return 1;
firstframe = 0;
/*
* FIXME: IMHO these tests do not belong in
* arch-dependent code, they are generic.
*/
ip = ftrace_graph_ret_addr(tsk, &graph_idx, ip, NULL);
#ifdef CONFIG_KPROBES
/*
* Mark stacktraces with kretprobed functions on them
* as unreliable.
*/
if (ip == (unsigned long)kretprobe_trampoline)
return 1;
#endif
if (!trace->skip)
trace->entries[trace->nr_entries++] = ip;
else
trace->skip--;
if (newsp == stack_end)
break;
if (trace->nr_entries >= trace->max_entries)
return -E2BIG;
sp = newsp;
}
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Torsten Duwe | 324 | 98.48% | 1 | 50.00% |
| Aneesh Kumar K.V | 5 | 1.52% | 1 | 50.00% |
| Total | 329 | 100.00% | 2 | 100.00% |
EXPORT_SYMBOL_GPL(save_stack_trace_tsk_reliable);
#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */
#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_NMI_IPI)
static void handle_backtrace_ipi(struct pt_regs *regs)
{
nmi_cpu_backtrace(regs);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Michael Ellerman | 16 | 100.00% | 1 | 100.00% |
| Total | 16 | 100.00% | 1 | 100.00% |
static void raise_backtrace_ipi(cpumask_t *mask)
{
unsigned int cpu;
for_each_cpu(cpu, mask) {
if (cpu == smp_processor_id())
handle_backtrace_ipi(NULL);
else
smp_send_safe_nmi_ipi(cpu, handle_backtrace_ipi, 5 * USEC_PER_SEC);
}
for_each_cpu(cpu, mask) {
struct paca_struct *p = paca_ptrs[cpu];
cpumask_clear_cpu(cpu, mask);
pr_warn("CPU %d didn't respond to backtrace IPI, inspecting paca.\n", cpu);
if (!virt_addr_valid(p)) {
pr_warn("paca pointer appears corrupt? (%px)\n", p);
continue;
}
pr_warn("irq_soft_mask: 0x%02x in_mce: %d in_nmi: %d",
p->irq_soft_mask, p->in_mce, p->in_nmi);
if (virt_addr_valid(p->__current))
pr_cont(" current: %d (%s)\n", p->__current->pid,
p->__current->comm);
else
pr_cont(" current pointer corrupt? (%px)\n", p->__current);
pr_warn("Back trace of paca->saved_r1 (0x%016llx) (possibly stale):\n", p->saved_r1);
show_stack(p->__current, (unsigned long *)p->saved_r1);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Michael Ellerman | 174 | 100.00% | 1 | 100.00% |
| Total | 174 | 100.00% | 1 | 100.00% |
void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
{
nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace_ipi);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Michael Ellerman | 22 | 100.00% | 1 | 100.00% |
| Total | 22 | 100.00% | 1 | 100.00% |
#endif /* defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_NMI_IPI) */
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Torsten Duwe | 350 | 40.65% | 1 | 7.14% |
| Michael Ellerman | 234 | 27.18% | 3 | 21.43% |
| Christoph Hellwig | 111 | 12.89% | 1 | 7.14% |
| Arnd Bergmann | 92 | 10.69% | 2 | 14.29% |
| Steven Rostedt | 36 | 4.18% | 1 | 7.14% |
| Thadeu Lima de Souza Cascardo | 24 | 2.79% | 1 | 7.14% |
| Aneesh Kumar K.V | 5 | 0.58% | 1 | 7.14% |
| Anton Blanchard | 5 | 0.58% | 2 | 14.29% |
| Ingo Molnar | 3 | 0.35% | 1 | 7.14% |
| Paul Gortmaker | 1 | 0.12% | 1 | 7.14% |
| Total | 861 | 100.00% | 14 | 100.00% |
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