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/*
* self test for change_page_attr.
*
* Clears the global bit on random pages in the direct mapping, then reverts
* and compares page tables forwards and afterwards.
*/
#include <linux/mm.h>
#include <linux/random.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#include <asm/kdebug.h>
enum {
NTEST = 400,
#ifdef CONFIG_X86_64
LOWEST_LEVEL = 4,
LPS = (1 << PMD_SHIFT),
#elif defined(CONFIG_X86_PAE)
LOWEST_LEVEL = 3,
LPS = (1 << PMD_SHIFT),
#else
LOWEST_LEVEL = 3, /* lookup_address lies here */
LPS = (1 << 22),
#endif
GPS = (1<<30)
};
#ifdef CONFIG_X86_64
#include <asm/proto.h>
#define max_mapped end_pfn_map
#else
#define max_mapped max_low_pfn
#endif
struct split_state {
long lpg, gpg, spg, exec;
long min_exec, max_exec;
};
static __init int print_split(struct split_state *s)
{
int printed = 0;
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_mapped; ) {
int level;
pte_t *pte;
unsigned long adr = (unsigned long)__va(i << PAGE_SHIFT);
pte = lookup_address(adr, &level);
if (!pte) {
if (!printed) {
dump_pagetable(adr);
printk("CPA %lx no pte level %d\n", adr, level);
printed = 1;
}
missed++;
i++;
continue;
}
if (level == 2 && sizeof(long) == 8) {
s->gpg++;
i += GPS/PAGE_SIZE;
} else if (level != LOWEST_LEVEL) {
if (!(pte_val(*pte) & _PAGE_PSE)) {
printk("%lx level %d but not PSE %Lx\n",
adr, 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 (adr < s->min_exec)
s->min_exec = adr;
if (adr > s->max_exec)
s->max_exec = adr;
}
}
printk("CPA mapping 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("CPA max_mapped %lu but expected %lu\n",
max_mapped, expected);
return 1;
}
return err;
}
static __init int state_same(struct split_state *a, struct split_state *b)
{
return a->lpg == b->lpg && a->gpg == b->gpg && a->spg == b->spg &&
a->exec == b->exec;
}
static unsigned long addr[NTEST] __initdata;
static unsigned len[NTEST] __initdata;
/* Change the global bit on random pages in the direct mapping */
static __init int exercise_pageattr(void)
{
int i, k;
pte_t *pte, pte0;
int level;
int err;
struct split_state sa, sb, sc;
int failed = 0;
unsigned long *bm;
printk("CPA exercising pageattr\n");
bm = vmalloc((max_mapped + 7) / 8);
if (!bm) {
printk("CPA Cannot vmalloc bitmap\n");
return -ENOMEM;
}
memset(bm, 0, (max_mapped + 7) / 8);
failed += print_split(&sa);
srandom32(100);
for (i = 0; i < NTEST; i++) {
unsigned long pfn = random32() % max_mapped;
addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
len[i] = random32() % 100;
len[i] = min_t(unsigned long, len[i], max_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) {
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;
}
err = change_page_attr(virt_to_page(addr[i]), len[i],
pte_pgprot(pte_clrhuge(pte_clrglobal(pte0))));
if (err < 0) {
printk("CPA %d failed %d\n", i, err);
failed++;
}
pte = lookup_address(addr[i], &level);
if (!pte || pte_global(*pte) || pte_huge(*pte)) {
printk("CPA %lx: bad pte %Lx\n", addr[i],
pte ? (u64)pte_val(*pte) : 0ULL);
failed++;
}
if (level != LOWEST_LEVEL) {
printk("CPA %lx: unexpected level %d\n", addr[i],
level);
failed++;
}
}
vfree(bm);
global_flush_tlb();
failed += print_split(&sb);
printk("CPA reverting everything\n");
for (i = 0; i < NTEST; i++) {
if (!addr[i])
continue;
pte = lookup_address(addr[i], &level);
if (!pte) {
printk("CPA lookup of %lx failed\n", addr[i]);
failed++;
continue;
}
err = change_page_attr(virt_to_page(addr[i]), len[i],
pte_pgprot(pte_mkglobal(*pte)));
if (err < 0) {
printk("CPA reverting failed: %d\n", err);
failed++;
}
pte = lookup_address(addr[i], &level);
if (!pte || !pte_global(*pte)) {
printk("CPA %lx: bad pte after revert %Lx\n", addr[i],
pte ? (u64)pte_val(*pte) : 0ULL);
failed++;
}
}
global_flush_tlb();
failed += print_split(&sc);
if (!state_same(&sa, &sc))
failed++;
if (failed)
printk("CPA selftests NOT PASSED. Please report.\n");
else
printk("CPA selftests PASSED\n");
return 0;
}
module_init(exercise_pageattr);
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