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Commit 85848dd7 authored by Catalin Marinas's avatar Catalin Marinas Committed by Russell King
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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: default avatarRabin Vincent <rabin.vincent@stericsson.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 6012191a

arch/arm/include/asm/smp_plat.h

+4 −0
Original line number Diff line number Diff line
@@ -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

arch/arm/mm/flush.c

+4 −9
Original line number Diff line number Diff line
@@ -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);