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ARM: 7757/1: mm: don't flush icache in switch_mm with hardware broadcasting

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When scheduling an mm on a CPU where it hasn't previously been used, we
flush the icache on that CPU so that any code loaded previously on
a different core can be safely executed.

For cores with hardware broadcasting of cache maintenance operations,
this is clearly unnecessary, since the inner-shareable invalidation in
__sync_icache_dcache will affect all CPUs.

This patch conditionalises the icache flush in switch_mm based on
cache_ops_need_broadcast().

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Albin Tonnerre <albin.tonnerre@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon 2013-06-12 12:25:56 +01:00 committed by Russell King
parent 2874865c12
commit 621a0147d5
1 changed files with 9 additions and 4 deletions
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13
arch/arm/include/asm/mmu_context.h
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@ -18,6 +18,7 @@
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/proc-fns.h>
#include <asm/smp_plat.h>
#include <asm-generic/mm_hooks.h>
void __check_vmalloc_seq(struct mm_struct *mm);
@ -98,12 +99,16 @@ switch_mm(struct mm_struct *prev, struct mm_struct *next,
#ifdef CONFIG_MMU
unsigned int cpu = smp_processor_id();
#ifdef CONFIG_SMP
/* check for possible thread migration */
if (!cpumask_empty(mm_cpumask(next)) &&
/*
* __sync_icache_dcache doesn't broadcast the I-cache invalidation,
* so check for possible thread migration and invalidate the I-cache
* if we're new to this CPU.
*/
if (cache_ops_need_broadcast() &&
!cpumask_empty(mm_cpumask(next)) &&
!cpumask_test_cpu(cpu, mm_cpumask(next)))
__flush_icache_all();
#endif
if (!cpumask_test_and_set_cpu(cpu, mm_cpumask(next)) || prev != next) {
check_and_switch_context(next, tsk);
if (cache_is_vivt())