linux/arch/s390/mm/page-states.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright IBM Corp. 2008
   4 *
   5 * Guest page hinting for unused pages.
   6 *
   7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/errno.h>
  12#include <linux/types.h>
  13#include <linux/mm.h>
  14#include <linux/memblock.h>
  15#include <linux/gfp.h>
  16#include <linux/init.h>
  17#include <asm/facility.h>
  18#include <asm/page-states.h>
  19
  20static int cmma_flag = 1;
  21
  22static int __init cmma(char *str)
  23{
  24        bool enabled;
  25
  26        if (!kstrtobool(str, &enabled))
  27                cmma_flag = enabled;
  28        return 1;
  29}
  30__setup("cmma=", cmma);
  31
  32static inline int cmma_test_essa(void)
  33{
  34        register unsigned long tmp asm("0") = 0;
  35        register int rc asm("1");
  36
  37        /* test ESSA_GET_STATE */
  38        asm volatile(
  39                "       .insn   rrf,0xb9ab0000,%1,%1,%2,0\n"
  40                "0:     la      %0,0\n"
  41                "1:\n"
  42                EX_TABLE(0b,1b)
  43                : "=&d" (rc), "+&d" (tmp)
  44                : "i" (ESSA_GET_STATE), "0" (-EOPNOTSUPP));
  45        return rc;
  46}
  47
  48void __init cmma_init(void)
  49{
  50        if (!cmma_flag)
  51                return;
  52        if (cmma_test_essa()) {
  53                cmma_flag = 0;
  54                return;
  55        }
  56        if (test_facility(147))
  57                cmma_flag = 2;
  58}
  59
  60static inline unsigned char get_page_state(struct page *page)
  61{
  62        unsigned char state;
  63
  64        asm volatile("  .insn   rrf,0xb9ab0000,%0,%1,%2,0"
  65                     : "=&d" (state)
  66                     : "a" (page_to_phys(page)),
  67                       "i" (ESSA_GET_STATE));
  68        return state & 0x3f;
  69}
  70
  71static inline void set_page_unused(struct page *page, int order)
  72{
  73        int i, rc;
  74
  75        for (i = 0; i < (1 << order); i++)
  76                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  77                             : "=&d" (rc)
  78                             : "a" (page_to_phys(page + i)),
  79                               "i" (ESSA_SET_UNUSED));
  80}
  81
  82static inline void set_page_stable_dat(struct page *page, int order)
  83{
  84        int i, rc;
  85
  86        for (i = 0; i < (1 << order); i++)
  87                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  88                             : "=&d" (rc)
  89                             : "a" (page_to_phys(page + i)),
  90                               "i" (ESSA_SET_STABLE));
  91}
  92
  93static inline void set_page_stable_nodat(struct page *page, int order)
  94{
  95        int i, rc;
  96
  97        for (i = 0; i < (1 << order); i++)
  98                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  99                             : "=&d" (rc)
 100                             : "a" (page_to_phys(page + i)),
 101                               "i" (ESSA_SET_STABLE_NODAT));
 102}
 103
 104static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end)
 105{
 106        unsigned long next;
 107        struct page *page;
 108        pmd_t *pmd;
 109
 110        pmd = pmd_offset(pud, addr);
 111        do {
 112                next = pmd_addr_end(addr, end);
 113                if (pmd_none(*pmd) || pmd_large(*pmd))
 114                        continue;
 115                page = virt_to_page(pmd_val(*pmd));
 116                set_bit(PG_arch_1, &page->flags);
 117        } while (pmd++, addr = next, addr != end);
 118}
 119
 120static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end)
 121{
 122        unsigned long next;
 123        struct page *page;
 124        pud_t *pud;
 125        int i;
 126
 127        pud = pud_offset(p4d, addr);
 128        do {
 129                next = pud_addr_end(addr, end);
 130                if (pud_none(*pud) || pud_large(*pud))
 131                        continue;
 132                if (!pud_folded(*pud)) {
 133                        page = virt_to_page(pud_val(*pud));
 134                        for (i = 0; i < 3; i++)
 135                                set_bit(PG_arch_1, &page[i].flags);
 136                }
 137                mark_kernel_pmd(pud, addr, next);
 138        } while (pud++, addr = next, addr != end);
 139}
 140
 141static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end)
 142{
 143        unsigned long next;
 144        struct page *page;
 145        p4d_t *p4d;
 146        int i;
 147
 148        p4d = p4d_offset(pgd, addr);
 149        do {
 150                next = p4d_addr_end(addr, end);
 151                if (p4d_none(*p4d))
 152                        continue;
 153                if (!p4d_folded(*p4d)) {
 154                        page = virt_to_page(p4d_val(*p4d));
 155                        for (i = 0; i < 3; i++)
 156                                set_bit(PG_arch_1, &page[i].flags);
 157                }
 158                mark_kernel_pud(p4d, addr, next);
 159        } while (p4d++, addr = next, addr != end);
 160}
 161
 162static void mark_kernel_pgd(void)
 163{
 164        unsigned long addr, next;
 165        struct page *page;
 166        pgd_t *pgd;
 167        int i;
 168
 169        addr = 0;
 170        pgd = pgd_offset_k(addr);
 171        do {
 172                next = pgd_addr_end(addr, MODULES_END);
 173                if (pgd_none(*pgd))
 174                        continue;
 175                if (!pgd_folded(*pgd)) {
 176                        page = virt_to_page(pgd_val(*pgd));
 177                        for (i = 0; i < 3; i++)
 178                                set_bit(PG_arch_1, &page[i].flags);
 179                }
 180                mark_kernel_p4d(pgd, addr, next);
 181        } while (pgd++, addr = next, addr != MODULES_END);
 182}
 183
 184void __init cmma_init_nodat(void)
 185{
 186        struct memblock_region *reg;
 187        struct page *page;
 188        unsigned long start, end, ix;
 189
 190        if (cmma_flag < 2)
 191                return;
 192        /* Mark pages used in kernel page tables */
 193        mark_kernel_pgd();
 194
 195        /* Set all kernel pages not used for page tables to stable/no-dat */
 196        for_each_memblock(memory, reg) {
 197                start = memblock_region_memory_base_pfn(reg);
 198                end = memblock_region_memory_end_pfn(reg);
 199                page = pfn_to_page(start);
 200                for (ix = start; ix < end; ix++, page++) {
 201                        if (__test_and_clear_bit(PG_arch_1, &page->flags))
 202                                continue;       /* skip page table pages */
 203                        if (!list_empty(&page->lru))
 204                                continue;       /* skip free pages */
 205                        set_page_stable_nodat(page, 0);
 206                }
 207        }
 208}
 209
 210void arch_free_page(struct page *page, int order)
 211{
 212        if (!cmma_flag)
 213                return;
 214        set_page_unused(page, order);
 215}
 216
 217void arch_alloc_page(struct page *page, int order)
 218{
 219        if (!cmma_flag)
 220                return;
 221        if (cmma_flag < 2)
 222                set_page_stable_dat(page, order);
 223        else
 224                set_page_stable_nodat(page, order);
 225}
 226
 227void arch_set_page_dat(struct page *page, int order)
 228{
 229        if (!cmma_flag)
 230                return;
 231        set_page_stable_dat(page, order);
 232}
 233
 234void arch_set_page_nodat(struct page *page, int order)
 235{
 236        if (cmma_flag < 2)
 237                return;
 238        set_page_stable_nodat(page, order);
 239}
 240
 241int arch_test_page_nodat(struct page *page)
 242{
 243        unsigned char state;
 244
 245        if (cmma_flag < 2)
 246                return 0;
 247        state = get_page_state(page);
 248        return !!(state & 0x20);
 249}
 250
 251void arch_set_page_states(int make_stable)
 252{
 253        unsigned long flags, order, t;
 254        struct list_head *l;
 255        struct page *page;
 256        struct zone *zone;
 257
 258        if (!cmma_flag)
 259                return;
 260        if (make_stable)
 261                drain_local_pages(NULL);
 262        for_each_populated_zone(zone) {
 263                spin_lock_irqsave(&zone->lock, flags);
 264                for_each_migratetype_order(order, t) {
 265                        list_for_each(l, &zone->free_area[order].free_list[t]) {
 266                                page = list_entry(l, struct page, lru);
 267                                if (make_stable)
 268                                        set_page_stable_dat(page, order);
 269                                else
 270                                        set_page_unused(page, order);
 271                        }
 272                }
 273                spin_unlock_irqrestore(&zone->lock, flags);
 274        }
 275}
 276