// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2008
*
* Guest page hinting for unused pages.
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/kernel.h>
#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;
static int __init cmma(char *str)
{
char *parm;
parm = strstrip(str);
if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
cmma_flag = 1;
return 1;
}
cmma_flag = 0;
if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
return 1;
return 0;
}
__setup("cmma=", cmma);
static inline int cmma_test_essa(void)
{
register unsigned long tmp asm("0") = 0;
register int rc asm("1");
/* test ESSA_GET_STATE */
asm volatile(
" .insn rrf,0xb9ab0000,%1,%1,%2,0\n"
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
: "=&d" (rc), "+&d" (tmp)
: "i" (ESSA_GET_STATE), "0" (-EOPNOTSUPP));
return rc;
}
void __init cmma_init(void)
{
if (!cmma_flag)
return;
if (cmma_test_essa()) {
cmma_flag = 0;
return;
}
if (test_facility(147))
cmma_flag = 2;
}
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;
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_UNUSED));
}
static inline void set_page_stable_dat(struct page *page, int 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_nodat(struct page *page, int 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_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;
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)
{
unsigned long flags, order, t;
struct list_head *l;
struct page *page;
struct zone *zone;
if (!cmma_flag)
return;
if (make_stable)
drain_local_pages(NULL);
for_each_populated_zone(zone) {
spin_lock_irqsave(&zone->lock, flags);
for_each_migratetype_order(order, t) {
list_for_each(l, &zone->free_area[order].free_list[t]) {
page = list_entry(l, struct page, lru);
if (make_stable)
set_page_stable_dat(page, 0);
else
set_page_unused(page, order);
}
}
spin_unlock_irqrestore(&zone->lock, flags);
}
}