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: Andi Kleen <ak@suse.de>
Cc: andreas.herrmann3@amd.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 270cab2e..7d9517a 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -31,6 +31,7 @@
int numpages;
int flushtlb;
unsigned long pfn;
+ unsigned force_split : 1;
};
#ifdef CONFIG_X86_64
@@ -262,6 +263,9 @@
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 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 @@
*/
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 @@
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 @@
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 @@
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);