Commit f3aca3d0 authored by Aaron Tomlin's avatar Aaron Tomlin Committed by Linus Torvalds

nmi: provide the option to issue an NMI back trace to every cpu but current

Sometimes it is preferred not to use the trigger_all_cpu_backtrace()
routine when one wants to avoid capturing a back trace for current.  For
instance if one was previously captured recently.

This patch provides a new routine namely
trigger_allbutself_cpu_backtrace() which offers the flexibility to issue
an NMI to every cpu but current and capture a back trace accordingly.

Patch x86 and sparc to support new routine.

[dzickus@redhat.com: add stub in #else clause]
[dzickus@redhat.com: don't print message in single processor case, wrap with get/put_cpu based on Oleg's suggestion]
[sfr@canb.auug.org.au: undo C99ism]
Signed-off-by: default avatarAaron Tomlin <atomlin@redhat.com>
Signed-off-by: default avatarDon Zickus <dzickus@redhat.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 88e15ce4
......@@ -89,7 +89,7 @@ static inline unsigned long get_softint(void)
return retval;
}
void arch_trigger_all_cpu_backtrace(void);
void arch_trigger_all_cpu_backtrace(bool);
#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
extern void *hardirq_stack[NR_CPUS];
......
......@@ -239,7 +239,7 @@ static void __global_reg_poll(struct global_reg_snapshot *gp)
}
}
void arch_trigger_all_cpu_backtrace(void)
void arch_trigger_all_cpu_backtrace(bool include_self)
{
struct thread_info *tp = current_thread_info();
struct pt_regs *regs = get_irq_regs();
......@@ -251,16 +251,22 @@ void arch_trigger_all_cpu_backtrace(void)
spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
this_cpu = raw_smp_processor_id();
__global_reg_self(tp, regs, this_cpu);
memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
if (include_self)
__global_reg_self(tp, regs, this_cpu);
smp_fetch_global_regs();
for_each_online_cpu(cpu) {
struct global_reg_snapshot *gp = &global_cpu_snapshot[cpu].reg;
struct global_reg_snapshot *gp;
if (!include_self && cpu == this_cpu)
continue;
gp = &global_cpu_snapshot[cpu].reg;
__global_reg_poll(gp);
......@@ -292,7 +298,7 @@ void arch_trigger_all_cpu_backtrace(void)
static void sysrq_handle_globreg(int key)
{
arch_trigger_all_cpu_backtrace();
arch_trigger_all_cpu_backtrace(true);
}
static struct sysrq_key_op sparc_globalreg_op = {
......
......@@ -43,7 +43,7 @@ extern int vector_used_by_percpu_irq(unsigned int vector);
extern void init_ISA_irqs(void);
#ifdef CONFIG_X86_LOCAL_APIC
void arch_trigger_all_cpu_backtrace(void);
void arch_trigger_all_cpu_backtrace(bool);
#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
#endif
......
......@@ -33,31 +33,41 @@ static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
/* "in progress" flag of arch_trigger_all_cpu_backtrace */
static unsigned long backtrace_flag;
void arch_trigger_all_cpu_backtrace(void)
void arch_trigger_all_cpu_backtrace(bool include_self)
{
int i;
int cpu = get_cpu();
if (test_and_set_bit(0, &backtrace_flag))
if (test_and_set_bit(0, &backtrace_flag)) {
/*
* If there is already a trigger_all_cpu_backtrace() in progress
* (backtrace_flag == 1), don't output double cpu dump infos.
*/
put_cpu();
return;
}
cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
if (!include_self)
cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
printk(KERN_INFO "sending NMI to all CPUs:\n");
apic->send_IPI_all(NMI_VECTOR);
if (!cpumask_empty(to_cpumask(backtrace_mask))) {
pr_info("sending NMI to %s CPUs:\n",
(include_self ? "all" : "other"));
apic->send_IPI_mask(to_cpumask(backtrace_mask), NMI_VECTOR);
}
/* Wait for up to 10 seconds for all CPUs to do the backtrace */
for (i = 0; i < 10 * 1000; i++) {
if (cpumask_empty(to_cpumask(backtrace_mask)))
break;
mdelay(1);
touch_softlockup_watchdog();
}
clear_bit(0, &backtrace_flag);
smp_mb__after_atomic();
put_cpu();
}
static int
......
......@@ -32,15 +32,24 @@ static inline void touch_nmi_watchdog(void)
#ifdef arch_trigger_all_cpu_backtrace
static inline bool trigger_all_cpu_backtrace(void)
{
arch_trigger_all_cpu_backtrace();
arch_trigger_all_cpu_backtrace(true);
return true;
}
static inline bool trigger_allbutself_cpu_backtrace(void)
{
arch_trigger_all_cpu_backtrace(false);
return true;
}
#else
static inline bool trigger_all_cpu_backtrace(void)
{
return false;
}
static inline bool trigger_allbutself_cpu_backtrace(void)
{
return false;
}
#endif
#ifdef CONFIG_LOCKUP_DETECTOR
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment