diff options
Diffstat (limited to 'arch/x86/mm/pageattr-test.c')
| -rw-r--r-- | arch/x86/mm/pageattr-test.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c new file mode 100644 index 000000000..a25588ad7 --- /dev/null +++ b/arch/x86/mm/pageattr-test.c @@ -0,0 +1,261 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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 <linux/vmalloc.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_SOFTW1; +} + +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_PRESENT) && !(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); + + for (i = 0; i < NTEST; i++) { + unsigned long pfn = prandom_u32() % max_pfn_mapped; + + addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT); + len[i] = prandom_u32() % 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; +} +device_initcall(start_pageattr_test); |