linux/arch/x86/mm/pat/cpa-test.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * self test for change_page_attr.
   4 *
   5 * Clears the a test pte bit on random pages in the direct mapping,
   6 * then reverts and compares page tables forwards and afterwards.
   7 */
   8#include <linux/memblock.h>
   9#include <linux/kthread.h>
  10#include <linux/random.h>
  11#include <linux/kernel.h>
  12#include <linux/init.h>
  13#include <linux/mm.h>
  14#include <linux/vmalloc.h>
  15
  16#include <asm/cacheflush.h>
  17#include <asm/pgtable.h>
  18#include <asm/kdebug.h>
  19
  20/*
  21 * Only print the results of the first pass:
  22 */
  23static __read_mostly int print = 1;
  24
  25enum {
  26        NTEST                   = 3 * 100,
  27        NPAGES                  = 100,
  28#ifdef CONFIG_X86_64
  29        LPS                     = (1 << PMD_SHIFT),
  30#elif defined(CONFIG_X86_PAE)
  31        LPS                     = (1 << PMD_SHIFT),
  32#else
  33        LPS                     = (1 << 22),
  34#endif
  35        GPS                     = (1<<30)
  36};
  37
  38#define PAGE_CPA_TEST   __pgprot(_PAGE_CPA_TEST)
  39
  40static int pte_testbit(pte_t pte)
  41{
  42        return pte_flags(pte) & _PAGE_SOFTW1;
  43}
  44
  45struct split_state {
  46        long lpg, gpg, spg, exec;
  47        long min_exec, max_exec;
  48};
  49
  50static int print_split(struct split_state *s)
  51{
  52        long i, expected, missed = 0;
  53        int err = 0;
  54
  55        s->lpg = s->gpg = s->spg = s->exec = 0;
  56        s->min_exec = ~0UL;
  57        s->max_exec = 0;
  58        for (i = 0; i < max_pfn_mapped; ) {
  59                unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
  60                unsigned int level;
  61                pte_t *pte;
  62
  63                pte = lookup_address(addr, &level);
  64                if (!pte) {
  65                        missed++;
  66                        i++;
  67                        continue;
  68                }
  69
  70                if (level == PG_LEVEL_1G && sizeof(long) == 8) {
  71                        s->gpg++;
  72                        i += GPS/PAGE_SIZE;
  73                } else if (level == PG_LEVEL_2M) {
  74                        if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
  75                                printk(KERN_ERR
  76                                        "%lx level %d but not PSE %Lx\n",
  77                                        addr, level, (u64)pte_val(*pte));
  78                                err = 1;
  79                        }
  80                        s->lpg++;
  81                        i += LPS/PAGE_SIZE;
  82                } else {
  83                        s->spg++;
  84                        i++;
  85                }
  86                if (!(pte_val(*pte) & _PAGE_NX)) {
  87                        s->exec++;
  88                        if (addr < s->min_exec)
  89                                s->min_exec = addr;
  90                        if (addr > s->max_exec)
  91                                s->max_exec = addr;
  92                }
  93        }
  94        if (print) {
  95                printk(KERN_INFO
  96                        " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
  97                        s->spg, s->lpg, s->gpg, s->exec,
  98                        s->min_exec != ~0UL ? s->min_exec : 0,
  99                        s->max_exec, missed);
 100        }
 101
 102        expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
 103        if (expected != i) {
 104                printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
 105                        max_pfn_mapped, expected);
 106                return 1;
 107        }
 108        return err;
 109}
 110
 111static unsigned long addr[NTEST];
 112static unsigned int len[NTEST];
 113
 114static struct page *pages[NPAGES];
 115static unsigned long addrs[NPAGES];
 116
 117/* Change the global bit on random pages in the direct mapping */
 118static int pageattr_test(void)
 119{
 120        struct split_state sa, sb, sc;
 121        unsigned long *bm;
 122        pte_t *pte, pte0;
 123        int failed = 0;
 124        unsigned int level;
 125        int i, k;
 126        int err;
 127
 128        if (print)
 129                printk(KERN_INFO "CPA self-test:\n");
 130
 131        bm = vzalloc((max_pfn_mapped + 7) / 8);
 132        if (!bm) {
 133                printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
 134                return -ENOMEM;
 135        }
 136
 137        failed += print_split(&sa);
 138
 139        for (i = 0; i < NTEST; i++) {
 140                unsigned long pfn = prandom_u32() % max_pfn_mapped;
 141
 142                addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
 143                len[i] = prandom_u32() % NPAGES;
 144                len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
 145
 146                if (len[i] == 0)
 147                        len[i] = 1;
 148
 149                pte = NULL;
 150                pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
 151
 152                for (k = 0; k < len[i]; k++) {
 153                        pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
 154                        if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
 155                            !(pte_val(*pte) & _PAGE_PRESENT)) {
 156                                addr[i] = 0;
 157                                break;
 158                        }
 159                        if (k == 0) {
 160                                pte0 = *pte;
 161                        } else {
 162                                if (pgprot_val(pte_pgprot(*pte)) !=
 163                                        pgprot_val(pte_pgprot(pte0))) {
 164                                        len[i] = k;
 165                                        break;
 166                                }
 167                        }
 168                        if (test_bit(pfn + k, bm)) {
 169                                len[i] = k;
 170                                break;
 171                        }
 172                        __set_bit(pfn + k, bm);
 173                        addrs[k] = addr[i] + k*PAGE_SIZE;
 174                        pages[k] = pfn_to_page(pfn + k);
 175                }
 176                if (!addr[i] || !pte || !k) {
 177                        addr[i] = 0;
 178                        continue;
 179                }
 180
 181                switch (i % 3) {
 182                case 0:
 183                        err = change_page_attr_set(&addr[i], len[i], PAGE_CPA_TEST, 0);
 184                        break;
 185
 186                case 1:
 187                        err = change_page_attr_set(addrs, len[1], PAGE_CPA_TEST, 1);
 188                        break;
 189
 190                case 2:
 191                        err = cpa_set_pages_array(pages, len[i], PAGE_CPA_TEST);
 192                        break;
 193                }
 194
 195
 196                if (err < 0) {
 197                        printk(KERN_ERR "CPA %d failed %d\n", i, err);
 198                        failed++;
 199                }
 200
 201                pte = lookup_address(addr[i], &level);
 202                if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
 203                        printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
 204                                pte ? (u64)pte_val(*pte) : 0ULL);
 205                        failed++;
 206                }
 207                if (level != PG_LEVEL_4K) {
 208                        printk(KERN_ERR "CPA %lx: unexpected level %d\n",
 209                                addr[i], level);
 210                        failed++;
 211                }
 212
 213        }
 214        vfree(bm);
 215
 216        failed += print_split(&sb);
 217
 218        for (i = 0; i < NTEST; i++) {
 219                if (!addr[i])
 220                        continue;
 221                pte = lookup_address(addr[i], &level);
 222                if (!pte) {
 223                        printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
 224                        failed++;
 225                        continue;
 226                }
 227                err = change_page_attr_clear(&addr[i], len[i], PAGE_CPA_TEST, 0);
 228                if (err < 0) {
 229                        printk(KERN_ERR "CPA reverting failed: %d\n", err);
 230                        failed++;
 231                }
 232                pte = lookup_address(addr[i], &level);
 233                if (!pte || pte_testbit(*pte)) {
 234                        printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
 235                                addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
 236                        failed++;
 237                }
 238
 239        }
 240
 241        failed += print_split(&sc);
 242
 243        if (failed) {
 244                WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
 245                return -EINVAL;
 246        } else {
 247                if (print)
 248                        printk(KERN_INFO "ok.\n");
 249        }
 250
 251        return 0;
 252}
 253
 254static int do_pageattr_test(void *__unused)
 255{
 256        while (!kthread_should_stop()) {
 257                schedule_timeout_interruptible(HZ*30);
 258                if (pageattr_test() < 0)
 259                        break;
 260                if (print)
 261                        print--;
 262        }
 263        return 0;
 264}
 265
 266static int start_pageattr_test(void)
 267{
 268        struct task_struct *p;
 269
 270        p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
 271        if (!IS_ERR(p))
 272                wake_up_process(p);
 273        else
 274                WARN_ON(1);
 275
 276        return 0;
 277}
 278device_initcall(start_pageattr_test);
 279