Commit c9caa02c authored by Andi Kleen's avatar Andi Kleen Committed by Ingo Molnar
Browse files

x86: add set_memory_4k to pageattr.c 



Add a new function to force split large pages into 4k pages.
This is needed for some followup optimizations.

I had to add a new field to cpa_data to pass down the information
that try_preserve_large_page should not run.

Right now no set_page_4k() because I didn't need it and all the
specialized users I have in mind would be more comfortable with
pure addresses. I also didn't export it because it's unlikely
external code needs it.

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Cc: andreas.herrmann3@amd.com
Cc: mingo@elte.hu
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cc615032

arch/x86/mm/pageattr.c

+16 −4
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ struct cpa_data { 
	int		numpages;

	int		flushtlb;

	unsigned long	pfn;

	unsigned	force_split : 1;

};



#ifdef CONFIG_X86_64
@@ -262,6 +263,9 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, 
	int i, do_split = 1;

	unsigned int level;



	if (cpa->force_split)

		return 1;



	spin_lock_irqsave(&pgd_lock, flags);

	/*

	 * Check for races, another CPU might have split this page
@@ -696,7 +700,8 @@ static inline int cache_attr(pgprot_t attr) 
}



static int change_page_attr_set_clr(unsigned long addr, int numpages,

				    pgprot_t mask_set, pgprot_t mask_clr)

				    pgprot_t mask_set, pgprot_t mask_clr,

				    int force_split)

{

	struct cpa_data cpa;

	int ret, cache, checkalias;
@@ -707,7 +712,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages, 
	 */

	mask_set = canon_pgprot(mask_set);

	mask_clr = canon_pgprot(mask_clr);

	if (!pgprot_val(mask_set) && !pgprot_val(mask_clr))

	if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split)

		return 0;



	/* Ensure we are PAGE_SIZE aligned */
@@ -724,6 +729,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages, 
	cpa.mask_set = mask_set;

	cpa.mask_clr = mask_clr;

	cpa.flushtlb = 0;

	cpa.force_split = force_split;



	/* No alias checking for _NX bit modifications */

	checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX;
@@ -762,13 +768,13 @@ out: 
static inline int change_page_attr_set(unsigned long addr, int numpages,

				       pgprot_t mask)

{

	return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0));

	return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0), 0);

}



static inline int change_page_attr_clear(unsigned long addr, int numpages,

					 pgprot_t mask)

{

	return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask);

	return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask, 0);

}



int _set_memory_uc(unsigned long addr, int numpages)
@@ -847,6 +853,12 @@ int set_memory_np(unsigned long addr, int numpages) 
	return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_PRESENT));

}



int set_memory_4k(unsigned long addr, int numpages)

{

	return change_page_attr_set_clr(addr, numpages, __pgprot(0),

					__pgprot(0), 1);

}



int set_pages_uc(struct page *page, int numpages)

{

	unsigned long addr = (unsigned long)page_address(page);

include/asm-x86/cacheflush.h

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ int set_memory_nx(unsigned long addr, int numpages); 
int set_memory_ro(unsigned long addr, int numpages);

int set_memory_rw(unsigned long addr, int numpages);

int set_memory_np(unsigned long addr, int numpages);

int set_memory_4k(unsigned long addr, int numpages);



void clflush_cache_range(void *addr, unsigned int size);

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