6252d702c5
Add support for different number of page table levels dependent on the highest address used for a process. This will cause a 31 bit process to use a two level page table instead of the four level page table that is the default after the pud has been introduced. Likewise a normal 64 bit process will use three levels instead of four. Only if a process runs out of the 4 tera bytes which can be addressed with a three level page table the fourth level is dynamically added. Then the process can use up to 8 peta byte. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
227 lines
6.3 KiB
C
227 lines
6.3 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 <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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DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
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pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
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char empty_zero_page[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
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void show_mem(void)
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{
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int i, total = 0, reserved = 0;
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int shared = 0, cached = 0;
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struct page *page;
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printk("Mem-info:\n");
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show_free_areas();
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printk("Free swap: %6ldkB\n", nr_swap_pages << (PAGE_SHIFT - 10));
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i = max_mapnr;
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while (i-- > 0) {
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if (!pfn_valid(i))
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continue;
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page = pfn_to_page(i);
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total++;
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if (PageReserved(page))
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reserved++;
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else if (PageSwapCache(page))
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cached++;
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else if (page_count(page))
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shared += page_count(page) - 1;
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}
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printk("%d pages of RAM\n", total);
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printk("%d reserved pages\n", reserved);
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printk("%d pages shared\n", shared);
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printk("%d pages swap cached\n", cached);
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printk("%lu pages dirty\n", global_page_state(NR_FILE_DIRTY));
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printk("%lu pages writeback\n", global_page_state(NR_WRITEBACK));
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printk("%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
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printk("%lu pages slab\n",
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global_page_state(NR_SLAB_RECLAIMABLE) +
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global_page_state(NR_SLAB_UNRECLAIMABLE));
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printk("%lu pages pagetables\n", global_page_state(NR_PAGETABLE));
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}
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static void __init setup_ro_region(void)
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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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pte_t new_pte;
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unsigned long address, end;
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address = ((unsigned long)&_stext) & PAGE_MASK;
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end = PFN_ALIGN((unsigned long)&_eshared);
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for (; address < end; address += PAGE_SIZE) {
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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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new_pte = mk_pte_phys(address, __pgprot(_PAGE_RO));
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*pte = new_pte;
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}
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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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static const int ssm_mask = 0x04000000L;
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unsigned long max_zone_pfns[MAX_NR_ZONES];
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unsigned long pgd_type;
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init_mm.pgd = swapper_pg_dir;
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S390_lowcore.kernel_asce = __pa(init_mm.pgd) & PAGE_MASK;
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#ifdef CONFIG_64BIT
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/* A three level page table (4TB) is enough for the kernel space. */
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S390_lowcore.kernel_asce |= _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
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pgd_type = _REGION3_ENTRY_EMPTY;
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#else
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S390_lowcore.kernel_asce |= _ASCE_TABLE_LENGTH;
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pgd_type = _SEGMENT_ENTRY_EMPTY;
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#endif
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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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setup_ro_region();
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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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__raw_local_irq_ssm(ssm_mask);
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memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
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#ifdef CONFIG_ZONE_DMA
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max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
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#endif
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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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}
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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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/* clear the zero-page */
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memset(empty_zero_page, 0, PAGE_SIZE);
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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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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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(unsigned long) 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_invalidate(&init_mm, address, pte);
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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_initmem(void)
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{
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unsigned long addr;
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addr = (unsigned long)(&__init_begin);
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for (; addr < (unsigned long)(&__init_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, POISON_FREE_INITMEM, PAGE_SIZE);
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free_page(addr);
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totalram_pages++;
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}
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printk ("Freeing unused kernel memory: %ldk freed\n",
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((unsigned long)&__init_end - (unsigned long)&__init_begin) >> 10);
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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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if (start < end)
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printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
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for (; start < end; start += PAGE_SIZE) {
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ClearPageReserved(virt_to_page(start));
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init_page_count(virt_to_page(start));
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free_page(start);
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totalram_pages++;
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}
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}
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#endif
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