x86: c_p_a(), add simple self test at boot
Since change_page_attr() is tricky code it is good to have some regression test code. This patch maps and unmaps some random pages in the direct mapping at boot and then dumps the state and does some simple sanity checks. Add it with a CONFIG option. Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -4,6 +4,7 @@
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obj-y := init_32.o pgtable_32.o fault_32.o ioremap_32.o extable.o pageattr_32.o mmap.o
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obj-$(CONFIG_CPA_DEBUG) += pageattr-test.o
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obj-$(CONFIG_NUMA) += discontig_32.o
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obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
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obj-$(CONFIG_HIGHMEM) += highmem_32.o
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@ -7,3 +7,4 @@ obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
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obj-$(CONFIG_NUMA) += numa_64.o
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obj-$(CONFIG_K8_NUMA) += k8topology_64.o
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obj-$(CONFIG_ACPI_NUMA) += srat_64.o
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obj-$(CONFIG_CPA_DEBUG) += pageattr-test.o
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@ -0,0 +1,233 @@
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/*
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* self test for change_page_attr.
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*
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* Clears the global bit on random pages in the direct mapping, then reverts
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* and compares page tables forwards and afterwards.
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*/
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/bootmem.h>
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#include <asm/cacheflush.h>
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#include <asm/pgtable.h>
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#include <asm/kdebug.h>
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enum {
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NTEST = 400,
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#ifdef CONFIG_X86_64
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LOWEST_LEVEL = 4,
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LPS = (1 << PMD_SHIFT),
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#elif defined(CONFIG_X86_PAE)
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LOWEST_LEVEL = 3,
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LPS = (1 << PMD_SHIFT),
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#else
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LOWEST_LEVEL = 3, /* lookup_address lies here */
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LPS = (1 << 22),
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#endif
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GPS = (1<<30)
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};
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#ifdef CONFIG_X86_64
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#include <asm/proto.h>
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#define max_mapped end_pfn_map
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#else
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#define max_mapped max_low_pfn
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#endif
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struct split_state {
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long lpg, gpg, spg, exec;
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long min_exec, max_exec;
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};
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static __init int print_split(struct split_state *s)
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{
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int printed = 0;
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long i, expected, missed = 0;
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int err = 0;
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s->lpg = s->gpg = s->spg = s->exec = 0;
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s->min_exec = ~0UL;
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s->max_exec = 0;
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for (i = 0; i < max_mapped; ) {
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int level;
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pte_t *pte;
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unsigned long adr = (unsigned long)__va(i << PAGE_SHIFT);
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pte = lookup_address(adr, &level);
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if (!pte) {
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if (!printed) {
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dump_pagetable(adr);
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printk("CPA %lx no pte level %d\n", adr, level);
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printed = 1;
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}
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missed++;
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i++;
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continue;
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}
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if (level == 2 && sizeof(long) == 8) {
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s->gpg++;
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i += GPS/PAGE_SIZE;
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} else if (level != LOWEST_LEVEL) {
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if (!(pte_val(*pte) & _PAGE_PSE)) {
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printk("%lx level %d but not PSE %Lx\n",
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adr, level, (u64)pte_val(*pte));
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err = 1;
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}
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s->lpg++;
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i += LPS/PAGE_SIZE;
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} else {
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s->spg++;
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i++;
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}
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if (!(pte_val(*pte) & _PAGE_NX)) {
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s->exec++;
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if (adr < s->min_exec)
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s->min_exec = adr;
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if (adr > s->max_exec)
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s->max_exec = adr;
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}
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}
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printk("CPA mapping 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
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s->spg, s->lpg, s->gpg, s->exec,
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s->min_exec != ~0UL ? s->min_exec : 0, s->max_exec, missed);
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expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
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if (expected != i) {
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printk("CPA max_mapped %lu but expected %lu\n",
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max_mapped, expected);
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return 1;
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}
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return err;
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}
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static __init int state_same(struct split_state *a, struct split_state *b)
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{
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return a->lpg == b->lpg && a->gpg == b->gpg && a->spg == b->spg &&
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a->exec == b->exec;
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}
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static unsigned long addr[NTEST] __initdata;
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static unsigned len[NTEST] __initdata;
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/* Change the global bit on random pages in the direct mapping */
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static __init int exercise_pageattr(void)
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{
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int i, k;
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pte_t *pte, pte0;
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int level;
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int err;
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struct split_state sa, sb, sc;
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int failed = 0;
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unsigned long *bm;
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printk("CPA exercising pageattr\n");
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bm = vmalloc((max_mapped + 7) / 8);
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if (!bm) {
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printk("CPA Cannot vmalloc bitmap\n");
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return -ENOMEM;
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}
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memset(bm, 0, (max_mapped + 7) / 8);
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failed += print_split(&sa);
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srandom32(100);
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for (i = 0; i < NTEST; i++) {
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unsigned long pfn = random32() % max_mapped;
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addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
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len[i] = random32() % 100;
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len[i] = min_t(unsigned long, len[i], max_mapped - pfn - 1);
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if (len[i] == 0)
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len[i] = 1;
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pte = NULL;
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pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
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for (k = 0; k < len[i]; k++) {
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pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
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if (!pte || pgprot_val(pte_pgprot(*pte)) == 0) {
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addr[i] = 0;
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break;
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}
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if (k == 0)
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pte0 = *pte;
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else if (pgprot_val(pte_pgprot(*pte)) !=
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pgprot_val(pte_pgprot(pte0))) {
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len[i] = k;
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break;
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}
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if (test_bit(pfn + k, bm)) {
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len[i] = k;
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break;
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}
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__set_bit(pfn + k, bm);
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}
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if (!addr[i] || !pte || !k) {
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addr[i] = 0;
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continue;
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}
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err = change_page_attr(virt_to_page(addr[i]), len[i],
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pte_pgprot(pte_clrhuge(pte_clrglobal(pte0))));
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if (err < 0) {
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printk("CPA %d failed %d\n", i, err);
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failed++;
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}
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pte = lookup_address(addr[i], &level);
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if (!pte || pte_global(*pte) || pte_huge(*pte)) {
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printk("CPA %lx: bad pte %Lx\n", addr[i],
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pte ? (u64)pte_val(*pte) : 0ULL);
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failed++;
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}
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if (level != LOWEST_LEVEL) {
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printk("CPA %lx: unexpected level %d\n", addr[i],
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level);
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failed++;
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}
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}
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vfree(bm);
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global_flush_tlb();
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failed += print_split(&sb);
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printk("CPA reverting everything\n");
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for (i = 0; i < NTEST; i++) {
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if (!addr[i])
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continue;
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pte = lookup_address(addr[i], &level);
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if (!pte) {
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printk("CPA lookup of %lx failed\n", addr[i]);
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failed++;
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continue;
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}
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err = change_page_attr(virt_to_page(addr[i]), len[i],
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pte_pgprot(pte_mkglobal(*pte)));
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if (err < 0) {
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printk("CPA reverting failed: %d\n", err);
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failed++;
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}
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pte = lookup_address(addr[i], &level);
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if (!pte || !pte_global(*pte)) {
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printk("CPA %lx: bad pte after revert %Lx\n", addr[i],
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pte ? (u64)pte_val(*pte) : 0ULL);
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failed++;
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}
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}
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global_flush_tlb();
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failed += print_split(&sc);
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if (!state_same(&sa, &sc))
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failed++;
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if (failed)
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printk("CPA selftests NOT PASSED. Please report.\n");
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else
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printk("CPA selftests PASSED\n");
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return 0;
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}
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module_init(exercise_pageattr);
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