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![Martin Schwidefsky](/assets/img/avatar_default.png)
The kernel address space of a 64 bit kernel currently uses a three level page table and the vmemmap array has a fixed address and a fixed maximum size. A three level page table is good enough for systems with less than 3.8TB of memory, for bigger systems four page table levels need to be used. Each page table level costs a bit of performance, use 3 levels for normal systems and 4 levels only for the really big systems. To avoid bloating sparse.o too much set MAX_PHYSMEM_BITS to 46 for a maximum of 64TB of memory. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
240 lines
6 KiB
C
240 lines
6 KiB
C
/*
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* arch/s390/mm/init.c
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Hartmut Penner (hp@de.ibm.com)
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1995 Linus Torvalds
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*/
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/bootmem.h>
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#include <linux/pfn.h>
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#include <linux/poison.h>
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#include <linux/initrd.h>
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#include <linux/export.h>
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#include <linux/gfp.h>
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#include <asm/processor.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/dma.h>
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#include <asm/lowcore.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/sections.h>
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pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
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unsigned long empty_zero_page, zero_page_mask;
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EXPORT_SYMBOL(empty_zero_page);
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static unsigned long setup_zero_pages(void)
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{
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struct cpuid cpu_id;
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unsigned int order;
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unsigned long size;
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struct page *page;
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int i;
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get_cpu_id(&cpu_id);
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switch (cpu_id.machine) {
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case 0x9672: /* g5 */
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case 0x2064: /* z900 */
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case 0x2066: /* z900 */
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case 0x2084: /* z990 */
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case 0x2086: /* z990 */
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case 0x2094: /* z9-109 */
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case 0x2096: /* z9-109 */
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order = 0;
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break;
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case 0x2097: /* z10 */
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case 0x2098: /* z10 */
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default:
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order = 2;
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break;
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}
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empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
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if (!empty_zero_page)
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panic("Out of memory in setup_zero_pages");
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page = virt_to_page((void *) empty_zero_page);
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split_page(page, order);
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for (i = 1 << order; i > 0; i--) {
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SetPageReserved(page);
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page++;
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}
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size = PAGE_SIZE << order;
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zero_page_mask = (size - 1) & PAGE_MASK;
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return 1UL << order;
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}
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/*
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* paging_init() sets up the page tables
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*/
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void __init paging_init(void)
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{
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unsigned long max_zone_pfns[MAX_NR_ZONES];
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unsigned long pgd_type, asce_bits;
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init_mm.pgd = swapper_pg_dir;
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#ifdef CONFIG_64BIT
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if (VMALLOC_END > (1UL << 42)) {
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asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
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pgd_type = _REGION2_ENTRY_EMPTY;
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} else {
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asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
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pgd_type = _REGION3_ENTRY_EMPTY;
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}
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#else
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asce_bits = _ASCE_TABLE_LENGTH;
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pgd_type = _SEGMENT_ENTRY_EMPTY;
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#endif
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S390_lowcore.kernel_asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
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clear_table((unsigned long *) init_mm.pgd, pgd_type,
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sizeof(unsigned long)*2048);
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vmem_map_init();
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/* enable virtual mapping in kernel mode */
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__ctl_load(S390_lowcore.kernel_asce, 1, 1);
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__ctl_load(S390_lowcore.kernel_asce, 7, 7);
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__ctl_load(S390_lowcore.kernel_asce, 13, 13);
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arch_local_irq_restore(4UL << (BITS_PER_LONG - 8));
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atomic_set(&init_mm.context.attach_count, 1);
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sparse_memory_present_with_active_regions(MAX_NUMNODES);
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sparse_init();
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memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
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max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
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max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
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free_area_init_nodes(max_zone_pfns);
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fault_init();
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}
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void __init mem_init(void)
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{
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unsigned long codesize, reservedpages, datasize, initsize;
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max_mapnr = num_physpages = max_low_pfn;
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high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
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/* Setup guest page hinting */
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cmma_init();
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/* this will put all low memory onto the freelists */
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totalram_pages += free_all_bootmem();
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totalram_pages -= setup_zero_pages(); /* Setup zeroed pages. */
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reservedpages = 0;
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codesize = (unsigned long) &_etext - (unsigned long) &_text;
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datasize = (unsigned long) &_edata - (unsigned long) &_etext;
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initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
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printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, %ldk data, %ldk init)\n",
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nr_free_pages() << (PAGE_SHIFT-10),
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max_mapnr << (PAGE_SHIFT-10),
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codesize >> 10,
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reservedpages << (PAGE_SHIFT-10),
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datasize >>10,
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initsize >> 10);
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printk("Write protected kernel read-only data: %#lx - %#lx\n",
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(unsigned long)&_stext,
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PFN_ALIGN((unsigned long)&_eshared) - 1);
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}
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#ifdef CONFIG_DEBUG_PAGEALLOC
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void kernel_map_pages(struct page *page, int numpages, int enable)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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unsigned long address;
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int i;
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for (i = 0; i < numpages; i++) {
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address = page_to_phys(page + i);
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pgd = pgd_offset_k(address);
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pud = pud_offset(pgd, address);
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pmd = pmd_offset(pud, address);
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pte = pte_offset_kernel(pmd, address);
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if (!enable) {
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__ptep_ipte(address, pte);
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pte_val(*pte) = _PAGE_TYPE_EMPTY;
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continue;
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}
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*pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));
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/* Flush cpu write queue. */
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mb();
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}
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}
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#endif
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void free_init_pages(char *what, unsigned long begin, unsigned long end)
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{
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unsigned long addr = begin;
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if (begin >= end)
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return;
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for (; addr < end; addr += PAGE_SIZE) {
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ClearPageReserved(virt_to_page(addr));
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init_page_count(virt_to_page(addr));
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memset((void *)(addr & PAGE_MASK), POISON_FREE_INITMEM,
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PAGE_SIZE);
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free_page(addr);
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totalram_pages++;
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}
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printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
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}
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void free_initmem(void)
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{
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free_init_pages("unused kernel memory",
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(unsigned long)&__init_begin,
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(unsigned long)&__init_end);
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}
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#ifdef CONFIG_BLK_DEV_INITRD
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void free_initrd_mem(unsigned long start, unsigned long end)
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{
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free_init_pages("initrd memory", start, end);
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}
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#endif
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#ifdef CONFIG_MEMORY_HOTPLUG
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int arch_add_memory(int nid, u64 start, u64 size)
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{
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struct pglist_data *pgdat;
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struct zone *zone;
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int rc;
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pgdat = NODE_DATA(nid);
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zone = pgdat->node_zones + ZONE_MOVABLE;
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rc = vmem_add_mapping(start, size);
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if (rc)
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return rc;
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rc = __add_pages(nid, zone, PFN_DOWN(start), PFN_DOWN(size));
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if (rc)
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vmem_remove_mapping(start, size);
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return rc;
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}
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#endif /* CONFIG_MEMORY_HOTPLUG */
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