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/*
* Suspend support specific for s390.
*
* Copyright IBM Corp. 2009
*
* Author(s): Hans-Joachim Picht <hans@linux.vnet.ibm.com>
*/
#include <linux/pfn.h>
#include <linux/mm.h>
#include <asm/system.h>
/*
* References to section boundaries
*/
extern const void __nosave_begin, __nosave_end;
/*
* The restore of the saved pages in an hibernation image will set
* the change and referenced bits in the storage key for each page.
* Overindication of the referenced bits after an hibernation cycle
* does not cause any harm but the overindication of the change bits
* would cause trouble.
* Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
* page to the most significant byte of the associated page frame
* number in the hibernation image.
*/
/*
* Key storage is allocated as a linked list of pages.
* The size of the keys array is (PAGE_SIZE - sizeof(long))
*/
struct page_key_data {
struct page_key_data *next;
unsigned char data[];
};
#define PAGE_KEY_DATA_SIZE (PAGE_SIZE - sizeof(struct page_key_data *))
static struct page_key_data *page_key_data;
static struct page_key_data *page_key_rp, *page_key_wp;
static unsigned long page_key_rx, page_key_wx;
/*
* For each page in the hibernation image one additional byte is
* stored in the most significant byte of the page frame number.
* On suspend no additional memory is required but on resume the
* keys need to be memorized until the page data has been restored.
* Only then can the storage keys be set to their old state.
*/
unsigned long page_key_additional_pages(unsigned long pages)
{
return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
}
/*
* Free page_key_data list of arrays.
*/
void page_key_free(void)
{
struct page_key_data *pkd;
while (page_key_data) {
pkd = page_key_data;
page_key_data = pkd->next;
free_page((unsigned long) pkd);
}
}
/*
* Allocate page_key_data list of arrays with enough room to store
* one byte for each page in the hibernation image.
*/
int page_key_alloc(unsigned long pages)
{
struct page_key_data *pk;
unsigned long size;
size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
while (size--) {
pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
if (!pk) {
page_key_free();
return -ENOMEM;
}
pk->next = page_key_data;
page_key_data = pk;
}
page_key_rp = page_key_wp = page_key_data;
page_key_rx = page_key_wx = 0;
return 0;
}
/*
* Save the storage key into the upper 8 bits of the page frame number.
*/
void page_key_read(unsigned long *pfn)
{
unsigned long addr;
addr = (unsigned long) page_address(pfn_to_page(*pfn));
*(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
}
/*
* Extract the storage key from the upper 8 bits of the page frame number
* and store it in the page_key_data list of arrays.
*/
void page_key_memorize(unsigned long *pfn)
{
page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
*(unsigned char *) pfn = 0;
if (++page_key_wx < PAGE_KEY_DATA_SIZE)
return;
page_key_wp = page_key_wp->next;
page_key_wx = 0;
}
/*
* Get the next key from the page_key_data list of arrays and set the
* storage key of the page referred by @address. If @address refers to
* a "safe" page the swsusp_arch_resume code will transfer the storage
* key from the buffer page to the original page.
*/
void page_key_write(void *address)
{
page_set_storage_key((unsigned long) address,
page_key_rp->data[page_key_rx], 0);
if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
return;
page_key_rp = page_key_rp->next;
page_key_rx = 0;
}
int pfn_is_nosave(unsigned long pfn)
{
unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
unsigned long nosave_end_pfn = PFN_DOWN(__pa(&__nosave_end));
/* Always save lowcore pages (LC protection might be enabled). */
if (pfn <= LC_PAGES)
return 0;
if (pfn >= nosave_begin_pfn && pfn < nosave_end_pfn)
return 1;
/* Skip memory holes and read-only pages (NSS, DCSS, ...). */
if (tprot(PFN_PHYS(pfn)))
return 1;
return 0;
}
void save_processor_state(void)
{
/* swsusp_arch_suspend() actually saves all cpu register contents.
* Machine checks must be disabled since swsusp_arch_suspend() stores
* register contents to their lowcore save areas. That's the same
* place where register contents on machine checks would be saved.
* To avoid register corruption disable machine checks.
* We must also disable machine checks in the new psw mask for
* program checks, since swsusp_arch_suspend() may generate program
* checks. Disabling machine checks for all other new psw masks is
* just paranoia.
*/
local_mcck_disable();
/* Disable lowcore protection */
__ctl_clear_bit(0,28);
S390_lowcore.external_new_psw.mask &= ~PSW_MASK_MCHECK;
S390_lowcore.svc_new_psw.mask &= ~PSW_MASK_MCHECK;
S390_lowcore.io_new_psw.mask &= ~PSW_MASK_MCHECK;
S390_lowcore.program_new_psw.mask &= ~PSW_MASK_MCHECK;
}
void restore_processor_state(void)
{
S390_lowcore.external_new_psw.mask |= PSW_MASK_MCHECK;
S390_lowcore.svc_new_psw.mask |= PSW_MASK_MCHECK;
S390_lowcore.io_new_psw.mask |= PSW_MASK_MCHECK;
S390_lowcore.program_new_psw.mask |= PSW_MASK_MCHECK;
/* Enable lowcore protection */
__ctl_set_bit(0,28);
local_mcck_enable();
}
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