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MIPS: Fix crash registers on non-crashing CPUs 

As part of handling a crash on an SMP system, an IPI is send to
all other CPUs to save their current registers and stop.  It was
using task_pt_regs(current) to get the registers, but that will
only be accurate if the CPU was interrupted running in userland.
Instead allow the architecture to pass in the registers (all
pass NULL now, but allow for the future) and then use get_irq_regs()
which should be accurate as we are in an interrupt.  Fall back to
task_pt_regs(current) if nothing else is available.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13050/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Corey Minyard 2016-04-11 09:10:19 -05:00 committed by Ralf Baechle
parent e03ac9f0c3
commit c80e1b62ff
1 changed files with 13 additions and 3 deletions
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16
arch/mips/kernel/crash.c
View File

@ -14,12 +14,22 @@ static int crashing_cpu = -1;
static cpumask_t cpus_in_crash = CPU_MASK_NONE; static cpumask_t cpus_in_crash = CPU_MASK_NONE;
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
static void crash_shutdown_secondary(void *ignore) static void crash_shutdown_secondary(void *passed_regs)
{ {
struct pt_regs *regs; struct pt_regs *regs = passed_regs;
int cpu = smp_processor_id(); int cpu = smp_processor_id();
regs = task_pt_regs(current); /*
* If we are passed registers, use those. Otherwise get the
* regs from the last interrupt, which should be correct, as
* we are in an interrupt. But if the regs are not there,
* pull them from the top of the stack. They are probably
* wrong, but we need something to keep from crashing again.
*/
if (!regs)
regs = get_irq_regs();
if (!regs)
regs = task_pt_regs(current);
if (!cpu_online(cpu)) if (!cpu_online(cpu))
return; return;