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Subject[RFC PATCH v3 11/12] arm: smp: use SMP crash-stop common code
Date
Make arm use the SMP common implementation of crash_smp_send_stop() and
its generic logic, by removing the arm crash_smp_send_stop() definition
and providing the needed arch specific helpers.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
arch/arm/kernel/machine_kexec.c | 29 ++++++++---------------------
1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 76300f3813e8..5289984e3941 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -29,8 +29,6 @@ extern unsigned long kexec_indirection_page;
extern unsigned long kexec_mach_type;
extern unsigned long kexec_boot_atags;

-static atomic_t waiting_for_crash_ipi;
-
/*
* Provide a dummy crash_notes definition while crash dump arrives to arm.
* This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
@@ -89,34 +87,23 @@ void machine_crash_nonpanic_core(void *unused)
crash_save_cpu(&regs, smp_processor_id());
flush_cache_all();

+ /* ensure saved regs writes are visible before going offline */
+ smp_wmb();
set_cpu_online(smp_processor_id(), false);
- atomic_dec(&waiting_for_crash_ipi);

+ /* ensure all writes visible before parking */
+ wmb();
while (1) {
cpu_relax();
wfe();
}
}

-void crash_smp_send_stop(void)
+void arch_smp_crash_call(cpumask_t *cpus, unsigned int __unused)
{
- static int cpus_stopped;
- unsigned long msecs;
-
- if (cpus_stopped)
- return;
-
- atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
- smp_call_function(machine_crash_nonpanic_core, NULL, false);
- msecs = 1000; /* Wait at most a second for the other cpus to stop */
- while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
- mdelay(1);
- msecs--;
- }
- if (atomic_read(&waiting_for_crash_ipi) > 0)
- pr_warn("Non-crashing CPUs did not react to IPI\n");
-
- cpus_stopped = 1;
+ preempt_disable();
+ smp_call_function_many(cpus, machine_crash_nonpanic_core, NULL, false);
+ preempt_enable();
}

static void machine_kexec_mask_interrupts(void)
--
2.17.1
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