[RFC PATCH v2 11/12] arm: smp: use SMP crash-stop common code

[Cristian Marussi]

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.maru...@arm.com>
---
 arch/arm/kernel/machine_kexec.c | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 76300f3813e8..d53973cae362 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 +87,21 @@ 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;
+       smp_call_function_many(cpus, machine_crash_nonpanic_core, NULL, false);
 }
 
 static void machine_kexec_mask_interrupts(void)
-- 
2.17.1