v4.19.13 snapshot.
diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c
new file mode 100644
index 0000000..a25588a
--- /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);