ARM: 7703/1: Disable preemption in broadcast_tlb*_a15_erratum()

Commit 93dc688 (ARM: 7684/1: errata: Workaround for Cortex-A15 erratum
798181 (TLBI/DSB operations)) introduces calls to smp_processor_id() and
smp_call_function_many() with preemption enabled. This patch disables
preemption and also optimises the smp_processor_id() call in
broadcast_tlb_mm_a15_erratum(). The broadcast_tlb_a15_erratum() function
is changed to use smp_call_function() which disables preemption.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Geoff Levand <geoff@infradead.org>
Reported-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 5 insertions, 4 deletions

diff --git a/arch/arm/kernel/smp_tlb.c b/arch/arm/kernel/smp_tlb.c
index e82e1d248772..9a52a07aa40e 100644
--- a/arch/arm/kernel/smp_tlb.c
+++ b/arch/arm/kernel/smp_tlb.c
@@ -98,21 +98,21 @@ static void broadcast_tlb_a15_erratum(void)
                 return;
 
         dummy_flush_tlb_a15_erratum();
-        smp_call_function_many(cpu_online_mask, ipi_flush_tlb_a15_erratum,
-                               NULL, 1);
+        smp_call_function(ipi_flush_tlb_a15_erratum, NULL, 1);
 }
 
 static void broadcast_tlb_mm_a15_erratum(struct mm_struct *mm)
 {
-        int cpu;
+        int cpu, this_cpu;
         cpumask_t mask = { CPU_BITS_NONE };
 
         if (!erratum_a15_798181())
                 return;
 
         dummy_flush_tlb_a15_erratum();
+        this_cpu = get_cpu();
         for_each_online_cpu(cpu) {
-                if (cpu == smp_processor_id())
+                if (cpu == this_cpu)
                         continue;
                 /*
                  * We only need to send an IPI if the other CPUs are running
@@ -127,6 +127,7 @@ static void broadcast_tlb_mm_a15_erratum(struct mm_struct *mm)
                         cpumask_set_cpu(cpu, &mask);
         }
         smp_call_function_many(&mask, ipi_flush_tlb_a15_erratum, NULL, 1);
+        put_cpu();
 }
 
 void flush_tlb_all(void)