v4.19.13 snapshot.
diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c
new file mode 100644
index 0000000..814f265
--- /dev/null
+++ b/arch/s390/mm/pgalloc.c
@@ -0,0 +1,667 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Page table allocation functions
+ *
+ * Copyright IBM Corp. 2016
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/sysctl.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+#include <asm/gmap.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+#ifdef CONFIG_PGSTE
+
+static int page_table_allocate_pgste_min = 0;
+static int page_table_allocate_pgste_max = 1;
+int page_table_allocate_pgste = 0;
+EXPORT_SYMBOL(page_table_allocate_pgste);
+
+static struct ctl_table page_table_sysctl[] = {
+ {
+ .procname = "allocate_pgste",
+ .data = &page_table_allocate_pgste,
+ .maxlen = sizeof(int),
+ .mode = S_IRUGO | S_IWUSR,
+ .proc_handler = proc_dointvec_minmax,
+ .extra1 = &page_table_allocate_pgste_min,
+ .extra2 = &page_table_allocate_pgste_max,
+ },
+ { }
+};
+
+static struct ctl_table page_table_sysctl_dir[] = {
+ {
+ .procname = "vm",
+ .maxlen = 0,
+ .mode = 0555,
+ .child = page_table_sysctl,
+ },
+ { }
+};
+
+static int __init page_table_register_sysctl(void)
+{
+ return register_sysctl_table(page_table_sysctl_dir) ? 0 : -ENOMEM;
+}
+__initcall(page_table_register_sysctl);
+
+#endif /* CONFIG_PGSTE */
+
+unsigned long *crst_table_alloc(struct mm_struct *mm)
+{
+ struct page *page = alloc_pages(GFP_KERNEL, 2);
+
+ if (!page)
+ return NULL;
+ arch_set_page_dat(page, 2);
+ return (unsigned long *) page_to_phys(page);
+}
+
+void crst_table_free(struct mm_struct *mm, unsigned long *table)
+{
+ free_pages((unsigned long) table, 2);
+}
+
+static void __crst_table_upgrade(void *arg)
+{
+ struct mm_struct *mm = arg;
+
+ if (current->active_mm == mm)
+ set_user_asce(mm);
+ __tlb_flush_local();
+}
+
+int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
+{
+ unsigned long *table, *pgd;
+ int rc, notify;
+
+ /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */
+ VM_BUG_ON(mm->context.asce_limit < _REGION2_SIZE);
+ rc = 0;
+ notify = 0;
+ while (mm->context.asce_limit < end) {
+ table = crst_table_alloc(mm);
+ if (!table) {
+ rc = -ENOMEM;
+ break;
+ }
+ spin_lock_bh(&mm->page_table_lock);
+ pgd = (unsigned long *) mm->pgd;
+ if (mm->context.asce_limit == _REGION2_SIZE) {
+ crst_table_init(table, _REGION2_ENTRY_EMPTY);
+ p4d_populate(mm, (p4d_t *) table, (pud_t *) pgd);
+ mm->pgd = (pgd_t *) table;
+ mm->context.asce_limit = _REGION1_SIZE;
+ mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+ _ASCE_USER_BITS | _ASCE_TYPE_REGION2;
+ mm_inc_nr_puds(mm);
+ } else {
+ crst_table_init(table, _REGION1_ENTRY_EMPTY);
+ pgd_populate(mm, (pgd_t *) table, (p4d_t *) pgd);
+ mm->pgd = (pgd_t *) table;
+ mm->context.asce_limit = -PAGE_SIZE;
+ mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+ _ASCE_USER_BITS | _ASCE_TYPE_REGION1;
+ }
+ notify = 1;
+ spin_unlock_bh(&mm->page_table_lock);
+ }
+ if (notify)
+ on_each_cpu(__crst_table_upgrade, mm, 0);
+ return rc;
+}
+
+void crst_table_downgrade(struct mm_struct *mm)
+{
+ pgd_t *pgd;
+
+ /* downgrade should only happen from 3 to 2 levels (compat only) */
+ VM_BUG_ON(mm->context.asce_limit != _REGION2_SIZE);
+
+ if (current->active_mm == mm) {
+ clear_user_asce();
+ __tlb_flush_mm(mm);
+ }
+
+ pgd = mm->pgd;
+ mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
+ mm->context.asce_limit = _REGION3_SIZE;
+ mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
+ _ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
+ crst_table_free(mm, (unsigned long *) pgd);
+
+ if (current->active_mm == mm)
+ set_user_asce(mm);
+}
+
+static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
+{
+ unsigned int old, new;
+
+ do {
+ old = atomic_read(v);
+ new = old ^ bits;
+ } while (atomic_cmpxchg(v, old, new) != old);
+ return new;
+}
+
+#ifdef CONFIG_PGSTE
+
+struct page *page_table_alloc_pgste(struct mm_struct *mm)
+{
+ struct page *page;
+ u64 *table;
+
+ page = alloc_page(GFP_KERNEL);
+ if (page) {
+ table = (u64 *)page_to_phys(page);
+ memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
+ memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
+ }
+ return page;
+}
+
+void page_table_free_pgste(struct page *page)
+{
+ __free_page(page);
+}
+
+#endif /* CONFIG_PGSTE */
+
+/*
+ * page table entry allocation/free routines.
+ */
+unsigned long *page_table_alloc(struct mm_struct *mm)
+{
+ unsigned long *table;
+ struct page *page;
+ unsigned int mask, bit;
+
+ /* Try to get a fragment of a 4K page as a 2K page table */
+ if (!mm_alloc_pgste(mm)) {
+ table = NULL;
+ spin_lock_bh(&mm->context.lock);
+ if (!list_empty(&mm->context.pgtable_list)) {
+ page = list_first_entry(&mm->context.pgtable_list,
+ struct page, lru);
+ mask = atomic_read(&page->_refcount) >> 24;
+ mask = (mask | (mask >> 4)) & 3;
+ if (mask != 3) {
+ table = (unsigned long *) page_to_phys(page);
+ bit = mask & 1; /* =1 -> second 2K */
+ if (bit)
+ table += PTRS_PER_PTE;
+ atomic_xor_bits(&page->_refcount,
+ 1U << (bit + 24));
+ list_del(&page->lru);
+ }
+ }
+ spin_unlock_bh(&mm->context.lock);
+ if (table)
+ return table;
+ }
+ /* Allocate a fresh page */
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ return NULL;
+ if (!pgtable_page_ctor(page)) {
+ __free_page(page);
+ return NULL;
+ }
+ arch_set_page_dat(page, 0);
+ /* Initialize page table */
+ table = (unsigned long *) page_to_phys(page);
+ if (mm_alloc_pgste(mm)) {
+ /* Return 4K page table with PGSTEs */
+ atomic_xor_bits(&page->_refcount, 3 << 24);
+ memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
+ memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
+ } else {
+ /* Return the first 2K fragment of the page */
+ atomic_xor_bits(&page->_refcount, 1 << 24);
+ memset64((u64 *)table, _PAGE_INVALID, 2 * PTRS_PER_PTE);
+ spin_lock_bh(&mm->context.lock);
+ list_add(&page->lru, &mm->context.pgtable_list);
+ spin_unlock_bh(&mm->context.lock);
+ }
+ return table;
+}
+
+void page_table_free(struct mm_struct *mm, unsigned long *table)
+{
+ struct page *page;
+ unsigned int bit, mask;
+
+ page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
+ if (!mm_alloc_pgste(mm)) {
+ /* Free 2K page table fragment of a 4K page */
+ bit = (__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
+ spin_lock_bh(&mm->context.lock);
+ mask = atomic_xor_bits(&page->_refcount, 1U << (bit + 24));
+ mask >>= 24;
+ if (mask & 3)
+ list_add(&page->lru, &mm->context.pgtable_list);
+ else
+ list_del(&page->lru);
+ spin_unlock_bh(&mm->context.lock);
+ if (mask != 0)
+ return;
+ } else {
+ atomic_xor_bits(&page->_refcount, 3U << 24);
+ }
+
+ pgtable_page_dtor(page);
+ __free_page(page);
+}
+
+void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
+ unsigned long vmaddr)
+{
+ struct mm_struct *mm;
+ struct page *page;
+ unsigned int bit, mask;
+
+ mm = tlb->mm;
+ page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
+ if (mm_alloc_pgste(mm)) {
+ gmap_unlink(mm, table, vmaddr);
+ table = (unsigned long *) (__pa(table) | 3);
+ tlb_remove_table(tlb, table);
+ return;
+ }
+ bit = (__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
+ spin_lock_bh(&mm->context.lock);
+ mask = atomic_xor_bits(&page->_refcount, 0x11U << (bit + 24));
+ mask >>= 24;
+ if (mask & 3)
+ list_add_tail(&page->lru, &mm->context.pgtable_list);
+ else
+ list_del(&page->lru);
+ spin_unlock_bh(&mm->context.lock);
+ table = (unsigned long *) (__pa(table) | (1U << bit));
+ tlb_remove_table(tlb, table);
+}
+
+static void __tlb_remove_table(void *_table)
+{
+ unsigned int mask = (unsigned long) _table & 3;
+ void *table = (void *)((unsigned long) _table ^ mask);
+ struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
+
+ switch (mask) {
+ case 0: /* pmd, pud, or p4d */
+ free_pages((unsigned long) table, 2);
+ break;
+ case 1: /* lower 2K of a 4K page table */
+ case 2: /* higher 2K of a 4K page table */
+ mask = atomic_xor_bits(&page->_refcount, mask << (4 + 24));
+ mask >>= 24;
+ if (mask != 0)
+ break;
+ /* fallthrough */
+ case 3: /* 4K page table with pgstes */
+ if (mask & 3)
+ atomic_xor_bits(&page->_refcount, 3 << 24);
+ pgtable_page_dtor(page);
+ __free_page(page);
+ break;
+ }
+}
+
+static void tlb_remove_table_smp_sync(void *arg)
+{
+ /* Simply deliver the interrupt */
+}
+
+static void tlb_remove_table_one(void *table)
+{
+ /*
+ * This isn't an RCU grace period and hence the page-tables cannot be
+ * assumed to be actually RCU-freed.
+ *
+ * It is however sufficient for software page-table walkers that rely
+ * on IRQ disabling. See the comment near struct mmu_table_batch.
+ */
+ smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
+ __tlb_remove_table(table);
+}
+
+static void tlb_remove_table_rcu(struct rcu_head *head)
+{
+ struct mmu_table_batch *batch;
+ int i;
+
+ batch = container_of(head, struct mmu_table_batch, rcu);
+
+ for (i = 0; i < batch->nr; i++)
+ __tlb_remove_table(batch->tables[i]);
+
+ free_page((unsigned long)batch);
+}
+
+void tlb_table_flush(struct mmu_gather *tlb)
+{
+ struct mmu_table_batch **batch = &tlb->batch;
+
+ if (*batch) {
+ call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
+ *batch = NULL;
+ }
+}
+
+void tlb_remove_table(struct mmu_gather *tlb, void *table)
+{
+ struct mmu_table_batch **batch = &tlb->batch;
+
+ tlb->mm->context.flush_mm = 1;
+ if (*batch == NULL) {
+ *batch = (struct mmu_table_batch *)
+ __get_free_page(GFP_NOWAIT | __GFP_NOWARN);
+ if (*batch == NULL) {
+ __tlb_flush_mm_lazy(tlb->mm);
+ tlb_remove_table_one(table);
+ return;
+ }
+ (*batch)->nr = 0;
+ }
+ (*batch)->tables[(*batch)->nr++] = table;
+ if ((*batch)->nr == MAX_TABLE_BATCH)
+ tlb_flush_mmu(tlb);
+}
+
+/*
+ * Base infrastructure required to generate basic asces, region, segment,
+ * and page tables that do not make use of enhanced features like EDAT1.
+ */
+
+static struct kmem_cache *base_pgt_cache;
+
+static unsigned long base_pgt_alloc(void)
+{
+ u64 *table;
+
+ table = kmem_cache_alloc(base_pgt_cache, GFP_KERNEL);
+ if (table)
+ memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
+ return (unsigned long) table;
+}
+
+static void base_pgt_free(unsigned long table)
+{
+ kmem_cache_free(base_pgt_cache, (void *) table);
+}
+
+static unsigned long base_crst_alloc(unsigned long val)
+{
+ unsigned long table;
+
+ table = __get_free_pages(GFP_KERNEL, CRST_ALLOC_ORDER);
+ if (table)
+ crst_table_init((unsigned long *)table, val);
+ return table;
+}
+
+static void base_crst_free(unsigned long table)
+{
+ free_pages(table, CRST_ALLOC_ORDER);
+}
+
+#define BASE_ADDR_END_FUNC(NAME, SIZE) \
+static inline unsigned long base_##NAME##_addr_end(unsigned long addr, \
+ unsigned long end) \
+{ \
+ unsigned long next = (addr + (SIZE)) & ~((SIZE) - 1); \
+ \
+ return (next - 1) < (end - 1) ? next : end; \
+}
+
+BASE_ADDR_END_FUNC(page, _PAGE_SIZE)
+BASE_ADDR_END_FUNC(segment, _SEGMENT_SIZE)
+BASE_ADDR_END_FUNC(region3, _REGION3_SIZE)
+BASE_ADDR_END_FUNC(region2, _REGION2_SIZE)
+BASE_ADDR_END_FUNC(region1, _REGION1_SIZE)
+
+static inline unsigned long base_lra(unsigned long address)
+{
+ unsigned long real;
+
+ asm volatile(
+ " lra %0,0(%1)\n"
+ : "=d" (real) : "a" (address) : "cc");
+ return real;
+}
+
+static int base_page_walk(unsigned long origin, unsigned long addr,
+ unsigned long end, int alloc)
+{
+ unsigned long *pte, next;
+
+ if (!alloc)
+ return 0;
+ pte = (unsigned long *) origin;
+ pte += (addr & _PAGE_INDEX) >> _PAGE_SHIFT;
+ do {
+ next = base_page_addr_end(addr, end);
+ *pte = base_lra(addr);
+ } while (pte++, addr = next, addr < end);
+ return 0;
+}
+
+static int base_segment_walk(unsigned long origin, unsigned long addr,
+ unsigned long end, int alloc)
+{
+ unsigned long *ste, next, table;
+ int rc;
+
+ ste = (unsigned long *) origin;
+ ste += (addr & _SEGMENT_INDEX) >> _SEGMENT_SHIFT;
+ do {
+ next = base_segment_addr_end(addr, end);
+ if (*ste & _SEGMENT_ENTRY_INVALID) {
+ if (!alloc)
+ continue;
+ table = base_pgt_alloc();
+ if (!table)
+ return -ENOMEM;
+ *ste = table | _SEGMENT_ENTRY;
+ }
+ table = *ste & _SEGMENT_ENTRY_ORIGIN;
+ rc = base_page_walk(table, addr, next, alloc);
+ if (rc)
+ return rc;
+ if (!alloc)
+ base_pgt_free(table);
+ cond_resched();
+ } while (ste++, addr = next, addr < end);
+ return 0;
+}
+
+static int base_region3_walk(unsigned long origin, unsigned long addr,
+ unsigned long end, int alloc)
+{
+ unsigned long *rtte, next, table;
+ int rc;
+
+ rtte = (unsigned long *) origin;
+ rtte += (addr & _REGION3_INDEX) >> _REGION3_SHIFT;
+ do {
+ next = base_region3_addr_end(addr, end);
+ if (*rtte & _REGION_ENTRY_INVALID) {
+ if (!alloc)
+ continue;
+ table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+ if (!table)
+ return -ENOMEM;
+ *rtte = table | _REGION3_ENTRY;
+ }
+ table = *rtte & _REGION_ENTRY_ORIGIN;
+ rc = base_segment_walk(table, addr, next, alloc);
+ if (rc)
+ return rc;
+ if (!alloc)
+ base_crst_free(table);
+ } while (rtte++, addr = next, addr < end);
+ return 0;
+}
+
+static int base_region2_walk(unsigned long origin, unsigned long addr,
+ unsigned long end, int alloc)
+{
+ unsigned long *rste, next, table;
+ int rc;
+
+ rste = (unsigned long *) origin;
+ rste += (addr & _REGION2_INDEX) >> _REGION2_SHIFT;
+ do {
+ next = base_region2_addr_end(addr, end);
+ if (*rste & _REGION_ENTRY_INVALID) {
+ if (!alloc)
+ continue;
+ table = base_crst_alloc(_REGION3_ENTRY_EMPTY);
+ if (!table)
+ return -ENOMEM;
+ *rste = table | _REGION2_ENTRY;
+ }
+ table = *rste & _REGION_ENTRY_ORIGIN;
+ rc = base_region3_walk(table, addr, next, alloc);
+ if (rc)
+ return rc;
+ if (!alloc)
+ base_crst_free(table);
+ } while (rste++, addr = next, addr < end);
+ return 0;
+}
+
+static int base_region1_walk(unsigned long origin, unsigned long addr,
+ unsigned long end, int alloc)
+{
+ unsigned long *rfte, next, table;
+ int rc;
+
+ rfte = (unsigned long *) origin;
+ rfte += (addr & _REGION1_INDEX) >> _REGION1_SHIFT;
+ do {
+ next = base_region1_addr_end(addr, end);
+ if (*rfte & _REGION_ENTRY_INVALID) {
+ if (!alloc)
+ continue;
+ table = base_crst_alloc(_REGION2_ENTRY_EMPTY);
+ if (!table)
+ return -ENOMEM;
+ *rfte = table | _REGION1_ENTRY;
+ }
+ table = *rfte & _REGION_ENTRY_ORIGIN;
+ rc = base_region2_walk(table, addr, next, alloc);
+ if (rc)
+ return rc;
+ if (!alloc)
+ base_crst_free(table);
+ } while (rfte++, addr = next, addr < end);
+ return 0;
+}
+
+/**
+ * base_asce_free - free asce and tables returned from base_asce_alloc()
+ * @asce: asce to be freed
+ *
+ * Frees all region, segment, and page tables that were allocated with a
+ * corresponding base_asce_alloc() call.
+ */
+void base_asce_free(unsigned long asce)
+{
+ unsigned long table = asce & _ASCE_ORIGIN;
+
+ if (!asce)
+ return;
+ switch (asce & _ASCE_TYPE_MASK) {
+ case _ASCE_TYPE_SEGMENT:
+ base_segment_walk(table, 0, _REGION3_SIZE, 0);
+ break;
+ case _ASCE_TYPE_REGION3:
+ base_region3_walk(table, 0, _REGION2_SIZE, 0);
+ break;
+ case _ASCE_TYPE_REGION2:
+ base_region2_walk(table, 0, _REGION1_SIZE, 0);
+ break;
+ case _ASCE_TYPE_REGION1:
+ base_region1_walk(table, 0, -_PAGE_SIZE, 0);
+ break;
+ }
+ base_crst_free(table);
+}
+
+static int base_pgt_cache_init(void)
+{
+ static DEFINE_MUTEX(base_pgt_cache_mutex);
+ unsigned long sz = _PAGE_TABLE_SIZE;
+
+ if (base_pgt_cache)
+ return 0;
+ mutex_lock(&base_pgt_cache_mutex);
+ if (!base_pgt_cache)
+ base_pgt_cache = kmem_cache_create("base_pgt", sz, sz, 0, NULL);
+ mutex_unlock(&base_pgt_cache_mutex);
+ return base_pgt_cache ? 0 : -ENOMEM;
+}
+
+/**
+ * base_asce_alloc - create kernel mapping without enhanced DAT features
+ * @addr: virtual start address of kernel mapping
+ * @num_pages: number of consecutive pages
+ *
+ * Generate an asce, including all required region, segment and page tables,
+ * that can be used to access the virtual kernel mapping. The difference is
+ * that the returned asce does not make use of any enhanced DAT features like
+ * e.g. large pages. This is required for some I/O functions that pass an
+ * asce, like e.g. some service call requests.
+ *
+ * Note: the returned asce may NEVER be attached to any cpu. It may only be
+ * used for I/O requests. tlb entries that might result because the
+ * asce was attached to a cpu won't be cleared.
+ */
+unsigned long base_asce_alloc(unsigned long addr, unsigned long num_pages)
+{
+ unsigned long asce, table, end;
+ int rc;
+
+ if (base_pgt_cache_init())
+ return 0;
+ end = addr + num_pages * PAGE_SIZE;
+ if (end <= _REGION3_SIZE) {
+ table = base_crst_alloc(_SEGMENT_ENTRY_EMPTY);
+ if (!table)
+ return 0;
+ rc = base_segment_walk(table, addr, end, 1);
+ asce = table | _ASCE_TYPE_SEGMENT | _ASCE_TABLE_LENGTH;
+ } else if (end <= _REGION2_SIZE) {
+ table = base_crst_alloc(_REGION3_ENTRY_EMPTY);
+ if (!table)
+ return 0;
+ rc = base_region3_walk(table, addr, end, 1);
+ asce = table | _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
+ } else if (end <= _REGION1_SIZE) {
+ table = base_crst_alloc(_REGION2_ENTRY_EMPTY);
+ if (!table)
+ return 0;
+ rc = base_region2_walk(table, addr, end, 1);
+ asce = table | _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
+ } else {
+ table = base_crst_alloc(_REGION1_ENTRY_EMPTY);
+ if (!table)
+ return 0;
+ rc = base_region1_walk(table, addr, end, 1);
+ asce = table | _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH;
+ }
+ if (rc) {
+ base_asce_free(asce);
+ asce = 0;
+ }
+ return asce;
+}