/* * self test for change_page_attr. * * Clears the a test pte bit on random pages in the direct mapping, * then reverts and compares page tables forwards and afterwards. */ #include <linux/bootmem.h> #include <linux/kthread.h> #include <linux/random.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/mm.h> #include <asm/cacheflush.h> #include <asm/pgtable.h> #include <asm/kdebug.h> /* * Only print the results of the first pass: */ static __read_mostly int print = 1; enum { NTEST = 400, #ifdef CONFIG_X86_64 LPS = (1 << PMD_SHIFT), #elif defined(CONFIG_X86_PAE) LPS = (1 << PMD_SHIFT), #else LPS = (1 << 22), #endif GPS = (1<<30) }; #define PAGE_CPA_TEST __pgprot(_PAGE_CPA_TEST) static int pte_testbit(pte_t pte) { return pte_flags(pte) & _PAGE_UNUSED1; } struct split_state { long lpg, gpg, spg, exec; long min_exec, max_exec; }; static int print_split(struct split_state *s) { long i, expected, missed = 0; int err = 0; s->lpg = s->gpg = s->spg = s->exec = 0; s->min_exec = ~0UL; s->max_exec = 0; for (i = 0; i < max_pfn_mapped; ) { unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT); unsigned int level; pte_t *pte; pte = lookup_address(addr, &level); if (!pte) { missed++; i++; continue; } if (level == PG_LEVEL_1G && sizeof(long) == 8) { s->gpg++; i += GPS/PAGE_SIZE; } else if (level == PG_LEVEL_2M) { if (!(pte_val(*pte) & _PAGE_PSE)) { printk(KERN_ERR "%lx level %d but not PSE %Lx\n", addr, level, (u64)pte_val(*pte)); err = 1; } s->lpg++; i += LPS/PAGE_SIZE; } else { s->spg++; i++; } if (!(pte_val(*pte) & _PAGE_NX)) { s->exec++; if (addr < s->min_exec) s->min_exec = addr; if (addr > s->max_exec) s->max_exec = addr; } } if (print) { printk(KERN_INFO " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n", s->spg, s->lpg, s->gpg, s->exec, s->min_exec != ~0UL ? s->min_exec : 0, s->max_exec, missed); } expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed; if (expected != i) { printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n", max_pfn_mapped, expected); return 1; } return err; } static unsigned long addr[NTEST]; static unsigned int len[NTEST]; /* Change the global bit on random pages in the direct mapping */ static int pageattr_test(void) { struct split_state sa, sb, sc; unsigned long *bm; pte_t *pte, pte0; int failed = 0; unsigned int level; int i, k; int err; unsigned long test_addr; if (print) printk(KERN_INFO "CPA self-test:\n"); bm = vzalloc((max_pfn_mapped + 7) / 8); if (!bm) { printk(KERN_ERR "CPA Cannot vmalloc bitmap\n"); return -ENOMEM; } failed += print_split(&sa); srandom32(100); for (i = 0; i < NTEST; i++) { unsigned long pfn = random32() % max_pfn_mapped; addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT); len[i] = random32() % 100; len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1); if (len[i] == 0) len[i] = 1; pte = NULL; pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */ for (k = 0; k < len[i]; k++) { pte = lookup_address(addr[i] + k*PAGE_SIZE, &level); if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 || !(pte_val(*pte) & _PAGE_PRESENT)) { addr[i] = 0; break; } if (k == 0) { pte0 = *pte; } else { if (pgprot_val(pte_pgprot(*pte)) != pgprot_val(pte_pgprot(pte0))) { len[i] = k; break; } } if (test_bit(pfn + k, bm)) { len[i] = k; break; } __set_bit(pfn + k, bm); } if (!addr[i] || !pte || !k) { addr[i] = 0; continue; } test_addr = addr[i]; err = change_page_attr_set(&test_addr, len[i], PAGE_CPA_TEST, 0); if (err < 0) { printk(KERN_ERR "CPA %d failed %d\n", i, err); failed++; } pte = lookup_address(addr[i], &level); if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) { printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i], pte ? (u64)pte_val(*pte) : 0ULL); failed++; } if (level != PG_LEVEL_4K) { printk(KERN_ERR "CPA %lx: unexpected level %d\n", addr[i], level); failed++; } } vfree(bm); failed += print_split(&sb); for (i = 0; i < NTEST; i++) { if (!addr[i]) continue; pte = lookup_address(addr[i], &level); if (!pte) { printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]); failed++; continue; } test_addr = addr[i]; err = change_page_attr_clear(&test_addr, len[i], PAGE_CPA_TEST, 0); if (err < 0) { printk(KERN_ERR "CPA reverting failed: %d\n", err); failed++; } pte = lookup_address(addr[i], &level); if (!pte || pte_testbit(*pte)) { printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n", addr[i], pte ? (u64)pte_val(*pte) : 0ULL); failed++; } } failed += print_split(&sc); if (failed) { WARN(1, KERN_ERR "NOT PASSED. Please report.\n"); return -EINVAL; } else { if (print) printk(KERN_INFO "ok.\n"); } return 0; } static int do_pageattr_test(void *__unused) { while (!kthread_should_stop()) { schedule_timeout_interruptible(HZ*30); if (pageattr_test() < 0) break; if (print) print--; } return 0; } static int start_pageattr_test(void) { struct task_struct *p; p = kthread_create(do_pageattr_test, NULL, "pageattr-test"); if (!IS_ERR(p)) wake_up_process(p); else WARN_ON(1); return 0; } module_init(start_pageattr_test);