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[S390] merge page_test_dirty and page_clear_dirty

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The page_clear_dirty primitive always sets the default storage key
which resets the access control bits and the fetch protection bit.
That will surprise a KVM guest that sets non-zero access control
bits or the fetch protection bit. Merge page_test_dirty and
page_clear_dirty back to a single function and only clear the
dirty bit from the storage key.

In addition move the function page_test_and_clear_dirty and
page_test_and_clear_young to page.h where they belong. This
requires to change the parameter from a struct page * to a page
frame number.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky
2011-05-23 10:24:39 +02:00
parent c26001d4e9
commit 2d42552d1c
5 changed files with 68 additions and 71 deletions
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56
arch/s390/include/asm/page.h
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@@ -107,8 +107,8 @@ typedef pte_t *pgtable_t;
#define __pgd(x) ((pgd_t) { (x) } )
#define __pgprot(x) ((pgprot_t) { (x) } )
static inline void
page_set_storage_key(unsigned long addr, unsigned int skey, int mapped)
static inline void page_set_storage_key(unsigned long addr,
unsigned char skey, int mapped)
{
if (!mapped)
asm volatile(".insn rrf,0xb22b0000,%0,%1,8,0"
@@ -117,15 +117,59 @@ page_set_storage_key(unsigned long addr, unsigned int skey, int mapped)
asm volatile("sske %0,%1" : : "d" (skey), "a" (addr));
}
static inline unsigned int
page_get_storage_key(unsigned long addr)
static inline unsigned char page_get_storage_key(unsigned long addr)
{
unsigned int skey;
unsigned char skey;
asm volatile("iske %0,%1" : "=d" (skey) : "a" (addr), "0" (0));
asm volatile("iske %0,%1" : "=d" (skey) : "a" (addr));
return skey;
}
static inline int page_reset_referenced(unsigned long addr)
{
unsigned int ipm;
asm volatile(
" rrbe 0,%1\n"
" ipm %0\n"
: "=d" (ipm) : "a" (addr) : "cc");
return !!(ipm & 0x20000000);
}
/* Bits int the storage key */
#define _PAGE_CHANGED 0x02 /* HW changed bit */
#define _PAGE_REFERENCED 0x04 /* HW referenced bit */
#define _PAGE_FP_BIT 0x08 /* HW fetch protection bit */
#define _PAGE_ACC_BITS 0xf0 /* HW access control bits */
/*
* Test and clear dirty bit in storage key.
* We can't clear the changed bit atomically. This is a potential
* race against modification of the referenced bit. This function
* should therefore only be called if it is not mapped in any
* address space.
*/
#define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
static inline int page_test_and_clear_dirty(unsigned long pfn, int mapped)
{
unsigned char skey;
skey = page_get_storage_key(pfn << PAGE_SHIFT);
if (!(skey & _PAGE_CHANGED))
return 0;
page_set_storage_key(pfn << PAGE_SHIFT, skey & ~_PAGE_CHANGED, mapped);
return 1;
}
/*
* Test and clear referenced bit in storage key.
*/
#define __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
static inline int page_test_and_clear_young(unsigned long pfn)
{
return page_reset_referenced(pfn << PAGE_SHIFT);
}
struct page;
void arch_free_page(struct page *page, int order);
void arch_alloc_page(struct page *page, int order);