Commit c9b5ad54 authored by Martin Schwidefsky's avatar Martin Schwidefsky

s390/mm: tag normal pages vs pages used in page tables

The ESSA instruction has a new option that allows to tag pages that
are not used as a page table. Without the tag the hypervisor has to
assume that any guest page could be used in a page table inside the
guest. This forces the hypervisor to flush all guest TLB entries
whenever a host page table entry is invalidated. With the tag
the host can skip the TLB flush if the page is tagged as normal page.
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 520eccdf
......@@ -13,6 +13,7 @@
#define ESSA_SET_POT_VOLATILE 4
#define ESSA_SET_STABLE_RESIDENT 5
#define ESSA_SET_STABLE_IF_RESIDENT 6
#define ESSA_SET_STABLE_NODAT 7
#define ESSA_MAX ESSA_SET_STABLE_IF_RESIDENT
......
......@@ -133,6 +133,9 @@ static inline int page_reset_referenced(unsigned long addr)
struct page;
void arch_free_page(struct page *page, int order);
void arch_alloc_page(struct page *page, int order);
void arch_set_page_dat(struct page *page, int order);
void arch_set_page_nodat(struct page *page, int order);
int arch_test_page_nodat(struct page *page);
void arch_set_page_states(int make_stable);
static inline int devmem_is_allowed(unsigned long pfn)
......
......@@ -106,7 +106,8 @@ extern void pfault_fini(void);
void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault);
extern void cmma_init(void);
void cmma_init(void);
void cmma_init_nodat(void);
extern void (*_machine_restart)(char *command);
extern void (*_machine_halt)(void);
......
......@@ -98,10 +98,16 @@ int page_key_alloc(unsigned long pages)
*/
void page_key_read(unsigned long *pfn)
{
struct page *page;
unsigned long addr;
addr = (unsigned long) page_address(pfn_to_page(*pfn));
*(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
unsigned char key;
page = pfn_to_page(*pfn);
addr = (unsigned long) page_address(page);
key = (unsigned char) page_get_storage_key(addr) & 0x7f;
if (arch_test_page_nodat(page))
key |= 0x80;
*(unsigned char *) pfn = key;
}
/*
......@@ -126,8 +132,16 @@ void page_key_memorize(unsigned long *pfn)
*/
void page_key_write(void *address)
{
page_set_storage_key((unsigned long) address,
page_key_rp->data[page_key_rx], 0);
struct page *page;
unsigned char key;
key = page_key_rp->data[page_key_rx];
page_set_storage_key((unsigned long) address, key & 0x7f, 0);
page = virt_to_page(address);
if (key & 0x80)
arch_set_page_nodat(page, 0);
else
arch_set_page_dat(page, 0);
if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
return;
page_key_rp = page_key_rp->next;
......
......@@ -157,6 +157,8 @@ int vdso_alloc_per_cpu(struct lowcore *lowcore)
page_frame = get_zeroed_page(GFP_KERNEL);
if (!segment_table || !page_table || !page_frame)
goto out;
arch_set_page_dat(virt_to_page(segment_table), SEGMENT_ORDER);
arch_set_page_dat(virt_to_page(page_table), 0);
/* Initialize per-cpu vdso data page */
vd = (struct vdso_per_cpu_data *) page_frame;
......
......@@ -137,6 +137,8 @@ void __init mem_init(void)
free_all_bootmem();
setup_zero_pages(); /* Setup zeroed pages. */
cmma_init_nodat();
mem_init_print_info(NULL);
}
......
......@@ -10,9 +10,10 @@
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <linux/init.h>
#include <asm/facility.h>
#include <asm/page-states.h>
static int cmma_flag = 1;
......@@ -36,14 +37,16 @@ __setup("cmma=", cmma);
static inline int cmma_test_essa(void)
{
register unsigned long tmp asm("0") = 0;
register int rc asm("1") = -EOPNOTSUPP;
register int rc asm("1");
/* test ESSA_GET_STATE */
asm volatile(
" .insn rrf,0xb9ab0000,%1,%1,0,0\n"
" .insn rrf,0xb9ab0000,%1,%1,%2,0\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "+&d" (rc), "+&d" (tmp));
: "=&d" (rc), "+&d" (tmp)
: "i" (ESSA_GET_STATE), "0" (-EOPNOTSUPP));
return rc;
}
......@@ -51,11 +54,26 @@ void __init cmma_init(void)
{
if (!cmma_flag)
return;
if (cmma_test_essa())
if (cmma_test_essa()) {
cmma_flag = 0;
return;
}
if (test_facility(147))
cmma_flag = 2;
}
static inline void set_page_unstable(struct page *page, int order)
static inline unsigned char get_page_state(struct page *page)
{
unsigned char state;
asm volatile(" .insn rrf,0xb9ab0000,%0,%1,%2,0"
: "=&d" (state)
: "a" (page_to_phys(page)),
"i" (ESSA_GET_STATE));
return state & 0x3f;
}
static inline void set_page_unused(struct page *page, int order)
{
int i, rc;
......@@ -66,14 +84,18 @@ static inline void set_page_unstable(struct page *page, int order)
"i" (ESSA_SET_UNUSED));
}
void arch_free_page(struct page *page, int order)
static inline void set_page_stable_dat(struct page *page, int order)
{
if (!cmma_flag)
return;
set_page_unstable(page, order);
int i, rc;
for (i = 0; i < (1 << order); i++)
asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
: "=&d" (rc)
: "a" (page_to_phys(page + i)),
"i" (ESSA_SET_STABLE));
}
static inline void set_page_stable(struct page *page, int order)
static inline void set_page_stable_nodat(struct page *page, int order)
{
int i, rc;
......@@ -81,14 +103,154 @@ static inline void set_page_stable(struct page *page, int order)
asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
: "=&d" (rc)
: "a" (page_to_phys(page + i)),
"i" (ESSA_SET_STABLE));
"i" (ESSA_SET_STABLE_NODAT));
}
static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end)
{
unsigned long next;
struct page *page;
pmd_t *pmd;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (pmd_none(*pmd) || pmd_large(*pmd))
continue;
page = virt_to_page(pmd_val(*pmd));
set_bit(PG_arch_1, &page->flags);
} while (pmd++, addr = next, addr != end);
}
static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end)
{
unsigned long next;
struct page *page;
pud_t *pud;
int i;
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
if (pud_none(*pud) || pud_large(*pud))
continue;
if (!pud_folded(*pud)) {
page = virt_to_page(pud_val(*pud));
for (i = 0; i < 3; i++)
set_bit(PG_arch_1, &page[i].flags);
}
mark_kernel_pmd(pud, addr, next);
} while (pud++, addr = next, addr != end);
}
static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end)
{
unsigned long next;
struct page *page;
p4d_t *p4d;
int i;
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
if (p4d_none(*p4d))
continue;
if (!p4d_folded(*p4d)) {
page = virt_to_page(p4d_val(*p4d));
for (i = 0; i < 3; i++)
set_bit(PG_arch_1, &page[i].flags);
}
mark_kernel_pud(p4d, addr, next);
} while (p4d++, addr = next, addr != end);
}
static void mark_kernel_pgd(void)
{
unsigned long addr, next;
struct page *page;
pgd_t *pgd;
int i;
addr = 0;
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, MODULES_END);
if (pgd_none(*pgd))
continue;
if (!pgd_folded(*pgd)) {
page = virt_to_page(pgd_val(*pgd));
for (i = 0; i < 3; i++)
set_bit(PG_arch_1, &page[i].flags);
}
mark_kernel_p4d(pgd, addr, next);
} while (pgd++, addr = next, addr != MODULES_END);
}
void __init cmma_init_nodat(void)
{
struct memblock_region *reg;
struct page *page;
unsigned long start, end, ix;
if (cmma_flag < 2)
return;
/* Mark pages used in kernel page tables */
mark_kernel_pgd();
/* Set all kernel pages not used for page tables to stable/no-dat */
for_each_memblock(memory, reg) {
start = memblock_region_memory_base_pfn(reg);
end = memblock_region_memory_end_pfn(reg);
page = pfn_to_page(start);
for (ix = start; ix < end; ix++, page++) {
if (__test_and_clear_bit(PG_arch_1, &page->flags))
continue; /* skip page table pages */
if (!list_empty(&page->lru))
continue; /* skip free pages */
set_page_stable_nodat(page, 0);
}
}
}
void arch_free_page(struct page *page, int order)
{
if (!cmma_flag)
return;
set_page_unused(page, order);
}
void arch_alloc_page(struct page *page, int order)
{
if (!cmma_flag)
return;
set_page_stable(page, order);
if (cmma_flag < 2)
set_page_stable_dat(page, order);
else
set_page_stable_nodat(page, order);
}
void arch_set_page_dat(struct page *page, int order)
{
if (!cmma_flag)
return;
set_page_stable_dat(page, order);
}
void arch_set_page_nodat(struct page *page, int order)
{
if (cmma_flag < 2)
return;
set_page_stable_nodat(page, order);
}
int arch_test_page_nodat(struct page *page)
{
unsigned char state;
if (cmma_flag < 2)
return 0;
state = get_page_state(page);
return !!(state & 0x20);
}
void arch_set_page_states(int make_stable)
......@@ -108,9 +270,9 @@ void arch_set_page_states(int make_stable)
list_for_each(l, &zone->free_area[order].free_list[t]) {
page = list_entry(l, struct page, lru);
if (make_stable)
set_page_stable(page, order);
set_page_stable_dat(page, 0);
else
set_page_unstable(page, order);
set_page_unused(page, order);
}
}
spin_unlock_irqrestore(&zone->lock, flags);
......
......@@ -57,6 +57,7 @@ unsigned long *crst_table_alloc(struct mm_struct *mm)
if (!page)
return NULL;
arch_set_page_dat(page, 2);
return (unsigned long *) page_to_phys(page);
}
......@@ -214,6 +215,7 @@ unsigned long *page_table_alloc(struct mm_struct *mm)
__free_page(page);
return NULL;
}
arch_set_page_dat(page, 0);
/* Initialize page table */
table = (unsigned long *) page_to_phys(page);
if (mm_alloc_pgste(mm)) {
......
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