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// 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/memblock.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);
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