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Commit 018d2ad0 authored by Andi Kleen's avatar Andi Kleen Committed by Linus Torvalds
Browse files

x86: change_page_attr bandaids 



- Disable CLFLUSH again; it is still broken. Always do WBINVD.
- Always flush in the i386 case, not only when there are deferred pages.

These are both brute-force inefficient fixes, to be improved
next release cycle.

The changes to i386 are a little more extensive than strictly
needed (some dead code added), but it is more similar to the x86-64 version
now and the dead code will be used soon.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 55181000

arch/i386/mm/pageattr.c

+18 −12
Original line number Diff line number Diff line
@@ -68,14 +68,23 @@ static struct page *split_large_page(unsigned long address, pgprot_t prot, 
	return base;

} 



static void flush_kernel_map(void *arg)

static void cache_flush_page(struct page *p)

{ 

	unsigned long adr = (unsigned long)arg;



	if (adr && cpu_has_clflush) {

	unsigned long adr = (unsigned long)page_address(p);

	int i;

	for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size)

		asm volatile("clflush (%0)" :: "r" (adr + i));

}



static void flush_kernel_map(void *arg)

{

	struct list_head *lh = (struct list_head *)arg;

	struct page *p;



	/* High level code is not ready for clflush yet */

	if (0 && cpu_has_clflush) {

		list_for_each_entry (p, lh, lru)

			cache_flush_page(p);

	} else if (boot_cpu_data.x86_model >= 4)

		wbinvd();
@@ -181,9 +190,9 @@ __change_page_attr(struct page *page, pgprot_t prot) 
	return 0;

} 



static inline void flush_map(void *adr)

static inline void flush_map(struct list_head *l)

{

	on_each_cpu(flush_kernel_map, adr, 1, 1);

	on_each_cpu(flush_kernel_map, l, 1, 1);

}



/*
@@ -225,11 +234,8 @@ void global_flush_tlb(void) 
	spin_lock_irq(&cpa_lock);

	list_replace_init(&df_list, &l);

	spin_unlock_irq(&cpa_lock);

	if (!cpu_has_clflush)

		flush_map(NULL);

	flush_map(&l);

	list_for_each_entry_safe(pg, next, &l, lru) {

		if (cpu_has_clflush)

			flush_map(page_address(pg));

		__free_page(pg);

	}

}

arch/x86_64/mm/pageattr.c

+4 −3
Original line number Diff line number Diff line
@@ -74,10 +74,11 @@ static void flush_kernel_map(void *arg) 
	struct page *pg;



	/* When clflush is available always use it because it is

	   much cheaper than WBINVD */

	if (!cpu_has_clflush)

	   much cheaper than WBINVD. Disable clflush for now because

	   the high level code is not ready yet */

	if (1 || !cpu_has_clflush)

		asm volatile("wbinvd" ::: "memory");

	list_for_each_entry(pg, l, lru) {

	else list_for_each_entry(pg, l, lru) {

		void *adr = page_address(pg);

		if (cpu_has_clflush)

			cache_flush_page(adr);