680 lines
17 KiB
C
680 lines
17 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Page table allocation functions
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*
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* Copyright IBM Corp. 2016
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#include <linux/sysctl.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <asm/mmu_context.h>
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#include <asm/pgalloc.h>
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#include <asm/gmap.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#ifdef CONFIG_PGSTE
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static int page_table_allocate_pgste_min = 0;
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static int page_table_allocate_pgste_max = 1;
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int page_table_allocate_pgste = 0;
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EXPORT_SYMBOL(page_table_allocate_pgste);
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static struct ctl_table page_table_sysctl[] = {
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{
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.procname = "allocate_pgste",
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.data = &page_table_allocate_pgste,
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.maxlen = sizeof(int),
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.mode = S_IRUGO | S_IWUSR,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &page_table_allocate_pgste_min,
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.extra2 = &page_table_allocate_pgste_max,
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},
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{ }
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};
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static struct ctl_table page_table_sysctl_dir[] = {
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{
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.procname = "vm",
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.maxlen = 0,
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.mode = 0555,
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.child = page_table_sysctl,
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},
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{ }
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};
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static int __init page_table_register_sysctl(void)
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{
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return register_sysctl_table(page_table_sysctl_dir) ? 0 : -ENOMEM;
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}
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__initcall(page_table_register_sysctl);
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#endif /* CONFIG_PGSTE */
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unsigned long *crst_table_alloc(struct mm_struct *mm)
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{
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struct page *page = alloc_pages(GFP_KERNEL, 2);
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if (!page)
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return NULL;
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arch_set_page_dat(page, 2);
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return (unsigned long *) page_to_phys(page);
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}
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void crst_table_free(struct mm_struct *mm, unsigned long *table)
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{
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free_pages((unsigned long) table, 2);
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}
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static void __crst_table_upgrade(void *arg)
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{
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struct mm_struct *mm = arg;
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/* we must change all active ASCEs to avoid the creation of new TLBs */
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if (current->active_mm == mm) {
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S390_lowcore.user_asce = mm->context.asce;
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if (current->thread.mm_segment == USER_DS) {
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__ctl_load(S390_lowcore.user_asce, 1, 1);
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/* Mark user-ASCE present in CR1 */
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clear_cpu_flag(CIF_ASCE_PRIMARY);
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}
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if (current->thread.mm_segment == USER_DS_SACF) {
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__ctl_load(S390_lowcore.user_asce, 7, 7);
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/* enable_sacf_uaccess does all or nothing */
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WARN_ON(!test_cpu_flag(CIF_ASCE_SECONDARY));
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}
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}
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__tlb_flush_local();
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}
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int crst_table_upgrade(struct mm_struct *mm, unsigned long end)
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{
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unsigned long *table, *pgd;
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int rc, notify;
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/* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */
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VM_BUG_ON(mm->context.asce_limit < _REGION2_SIZE);
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rc = 0;
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notify = 0;
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while (mm->context.asce_limit < end) {
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table = crst_table_alloc(mm);
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if (!table) {
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rc = -ENOMEM;
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break;
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}
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spin_lock_bh(&mm->page_table_lock);
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pgd = (unsigned long *) mm->pgd;
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if (mm->context.asce_limit == _REGION2_SIZE) {
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crst_table_init(table, _REGION2_ENTRY_EMPTY);
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p4d_populate(mm, (p4d_t *) table, (pud_t *) pgd);
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mm->pgd = (pgd_t *) table;
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mm->context.asce_limit = _REGION1_SIZE;
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mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
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_ASCE_USER_BITS | _ASCE_TYPE_REGION2;
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mm_inc_nr_puds(mm);
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} else {
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crst_table_init(table, _REGION1_ENTRY_EMPTY);
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pgd_populate(mm, (pgd_t *) table, (p4d_t *) pgd);
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mm->pgd = (pgd_t *) table;
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mm->context.asce_limit = -PAGE_SIZE;
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mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
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_ASCE_USER_BITS | _ASCE_TYPE_REGION1;
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}
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notify = 1;
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spin_unlock_bh(&mm->page_table_lock);
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}
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if (notify)
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on_each_cpu(__crst_table_upgrade, mm, 0);
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return rc;
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}
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void crst_table_downgrade(struct mm_struct *mm)
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{
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pgd_t *pgd;
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/* downgrade should only happen from 3 to 2 levels (compat only) */
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VM_BUG_ON(mm->context.asce_limit != _REGION2_SIZE);
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if (current->active_mm == mm) {
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clear_user_asce();
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__tlb_flush_mm(mm);
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}
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pgd = mm->pgd;
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mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN);
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mm->context.asce_limit = _REGION3_SIZE;
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mm->context.asce = __pa(mm->pgd) | _ASCE_TABLE_LENGTH |
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_ASCE_USER_BITS | _ASCE_TYPE_SEGMENT;
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crst_table_free(mm, (unsigned long *) pgd);
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if (current->active_mm == mm)
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set_user_asce(mm);
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}
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static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits)
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{
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unsigned int old, new;
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do {
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old = atomic_read(v);
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new = old ^ bits;
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} while (atomic_cmpxchg(v, old, new) != old);
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return new;
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}
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#ifdef CONFIG_PGSTE
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struct page *page_table_alloc_pgste(struct mm_struct *mm)
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{
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struct page *page;
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u64 *table;
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page = alloc_page(GFP_KERNEL);
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if (page) {
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table = (u64 *)page_to_phys(page);
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memset64(table, _PAGE_INVALID, PTRS_PER_PTE);
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memset64(table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
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}
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return page;
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}
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void page_table_free_pgste(struct page *page)
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{
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__free_page(page);
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}
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#endif /* CONFIG_PGSTE */
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/*
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* page table entry allocation/free routines.
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*/
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unsigned long *page_table_alloc(struct mm_struct *mm)
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{
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unsigned long *table;
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struct page *page;
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unsigned int mask, bit;
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/* Try to get a fragment of a 4K page as a 2K page table */
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if (!mm_alloc_pgste(mm)) {
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table = NULL;
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spin_lock_bh(&mm->context.lock);
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if (!list_empty(&mm->context.pgtable_list)) {
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page = list_first_entry(&mm->context.pgtable_list,
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struct page, lru);
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mask = atomic_read(&page->_refcount) >> 24;
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mask = (mask | (mask >> 4)) & 3;
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if (mask != 3) {
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table = (unsigned long *) page_to_phys(page);
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bit = mask & 1; /* =1 -> second 2K */
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if (bit)
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table += PTRS_PER_PTE;
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atomic_xor_bits(&page->_refcount,
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1U << (bit + 24));
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list_del(&page->lru);
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}
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}
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spin_unlock_bh(&mm->context.lock);
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if (table)
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return table;
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}
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/* Allocate a fresh page */
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page = alloc_page(GFP_KERNEL);
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if (!page)
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return NULL;
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if (!pgtable_page_ctor(page)) {
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__free_page(page);
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return NULL;
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}
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arch_set_page_dat(page, 0);
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/* Initialize page table */
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table = (unsigned long *) page_to_phys(page);
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if (mm_alloc_pgste(mm)) {
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/* Return 4K page table with PGSTEs */
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atomic_xor_bits(&page->_refcount, 3 << 24);
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memset64((u64 *)table, _PAGE_INVALID, PTRS_PER_PTE);
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memset64((u64 *)table + PTRS_PER_PTE, 0, PTRS_PER_PTE);
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} else {
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/* Return the first 2K fragment of the page */
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atomic_xor_bits(&page->_refcount, 1 << 24);
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memset64((u64 *)table, _PAGE_INVALID, 2 * PTRS_PER_PTE);
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spin_lock_bh(&mm->context.lock);
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list_add(&page->lru, &mm->context.pgtable_list);
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spin_unlock_bh(&mm->context.lock);
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}
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return table;
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}
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void page_table_free(struct mm_struct *mm, unsigned long *table)
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{
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struct page *page;
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unsigned int bit, mask;
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page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
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if (!mm_alloc_pgste(mm)) {
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/* Free 2K page table fragment of a 4K page */
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bit = (__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t));
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spin_lock_bh(&mm->context.lock);
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mask = atomic_xor_bits(&page->_refcount, 1U << (bit + 24));
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mask >>= 24;
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if (mask & 3)
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list_add(&page->lru, &mm->context.pgtable_list);
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else
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list_del(&page->lru);
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spin_unlock_bh(&mm->context.lock);
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if (mask != 0)
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return;
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} else {
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atomic_xor_bits(&page->_refcount, 3U << 24);
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}
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pgtable_page_dtor(page);
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__free_page(page);
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}
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void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table,
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unsigned long vmaddr)
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{
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struct mm_struct *mm;
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struct page *page;
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unsigned int bit, mask;
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mm = tlb->mm;
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page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
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if (mm_alloc_pgste(mm)) {
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gmap_unlink(mm, table, vmaddr);
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table = (unsigned long *) (__pa(table) | 3);
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tlb_remove_table(tlb, table);
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return;
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}
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bit = (__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t));
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spin_lock_bh(&mm->context.lock);
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mask = atomic_xor_bits(&page->_refcount, 0x11U << (bit + 24));
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mask >>= 24;
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if (mask & 3)
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list_add_tail(&page->lru, &mm->context.pgtable_list);
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else
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list_del(&page->lru);
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spin_unlock_bh(&mm->context.lock);
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table = (unsigned long *) (__pa(table) | (1U << bit));
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tlb_remove_table(tlb, table);
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}
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static void __tlb_remove_table(void *_table)
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{
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unsigned int mask = (unsigned long) _table & 3;
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void *table = (void *)((unsigned long) _table ^ mask);
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struct page *page = pfn_to_page(__pa(table) >> PAGE_SHIFT);
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switch (mask) {
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case 0: /* pmd, pud, or p4d */
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free_pages((unsigned long) table, 2);
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break;
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case 1: /* lower 2K of a 4K page table */
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case 2: /* higher 2K of a 4K page table */
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mask = atomic_xor_bits(&page->_refcount, mask << (4 + 24));
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mask >>= 24;
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if (mask != 0)
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break;
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/* fallthrough */
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case 3: /* 4K page table with pgstes */
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if (mask & 3)
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atomic_xor_bits(&page->_refcount, 3 << 24);
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pgtable_page_dtor(page);
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__free_page(page);
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break;
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}
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}
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static void tlb_remove_table_smp_sync(void *arg)
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{
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/* Simply deliver the interrupt */
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}
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static void tlb_remove_table_one(void *table)
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{
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/*
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* This isn't an RCU grace period and hence the page-tables cannot be
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* assumed to be actually RCU-freed.
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*
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* It is however sufficient for software page-table walkers that rely
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* on IRQ disabling. See the comment near struct mmu_table_batch.
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*/
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smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
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__tlb_remove_table(table);
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}
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static void tlb_remove_table_rcu(struct rcu_head *head)
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{
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struct mmu_table_batch *batch;
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int i;
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batch = container_of(head, struct mmu_table_batch, rcu);
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for (i = 0; i < batch->nr; i++)
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__tlb_remove_table(batch->tables[i]);
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free_page((unsigned long)batch);
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}
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void tlb_table_flush(struct mmu_gather *tlb)
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{
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struct mmu_table_batch **batch = &tlb->batch;
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|
|
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;
|
||
|
|
}
|