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ARM: 6381/1: Use lazy cache flushing on ARMv7 SMP systems 

ARMv7 processors like Cortex-A9 broadcast the cache maintenance
operations in hardware. This patch allows the
flush_dcache_page/update_mmu_cache pair to work in lazy flushing mode
similar to the UP case.

Note that cache flushing on SMP systems now takes place via the
set_pte_at() call (__sync_icache_dcache) and there is no race with other
CPUs executing code from the new PTE before the cache flushing took
place.

Tested-by: Rabin Vincent <rabin.vincent@stericsson.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas 2010-09-13 15:58:37 +01:00 committed by Russell King
parent 6012191aa9
commit 85848dd7ab
2 changed files with 8 additions and 9 deletions
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4
arch/arm/include/asm/smp_plat.h
View File

@ -13,9 +13,13 @@ static inline int tlb_ops_need_broadcast(void)
return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 2;
}
#if !defined(CONFIG_SMP) || __LINUX_ARM_ARCH__ >= 7
#define cache_ops_need_broadcast() 0
#else
static inline int cache_ops_need_broadcast(void)
{
return ((read_cpuid_ext(CPUID_EXT_MMFR3) >> 12) & 0xf) < 1;
}
#endif
#endif

13
arch/arm/mm/flush.c
View File

@ -17,6 +17,7 @@
#include <asm/smp_plat.h>
#include <asm/system.h>
#include <asm/tlbflush.h>
#include <asm/smp_plat.h>
#include "mm.h"
@ -93,12 +94,10 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsig
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#endif
#ifdef CONFIG_SMP
static void flush_ptrace_access_other(void *args)
{
__flush_icache_all();
}
#endif
static
void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
@ -122,11 +121,9 @@ void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
if (vma->vm_flags & VM_EXEC) {
unsigned long addr = (unsigned long)kaddr;
__cpuc_coherent_kern_range(addr, addr + len);
#ifdef CONFIG_SMP
if (cache_ops_need_broadcast())
smp_call_function(flush_ptrace_access_other,
NULL, 1);
#endif
}
}
@ -276,12 +273,10 @@ void flush_dcache_page(struct page *page)
mapping = page_mapping(page);
#ifndef CONFIG_SMP
if (mapping && !mapping_mapped(mapping))
if (!cache_ops_need_broadcast() &&
mapping && !mapping_mapped(mapping))
clear_bit(PG_dcache_clean, &page->flags);
else
#endif
{
else {
__flush_dcache_page(mapping, page);
if (mapping && cache_is_vivt())
__flush_dcache_aliases(mapping, page);