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

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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: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Aaron Tomlin
2014-06-23 13:22:05 -07:00
committed by Linus Torvalds
parent 88e15ce402
commit f3aca3d095
5 changed files with 38 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
arch/sparc/kernel/process_64.c
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@@ -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 = {