288 lines
7.5 KiB
C
288 lines
7.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/arch/alpha/mm/init.c
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*
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* Copyright (C) 1995 Linus Torvalds
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*/
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/* 2.3.x zone allocator, 1999 Andrea Arcangeli <andrea@suse.de> */
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#include <linux/pagemap.h>
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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/init.h>
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#include <linux/memblock.h> /* max_low_pfn */
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#include <linux/vmalloc.h>
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#include <linux/gfp.h>
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#include <linux/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/hwrpb.h>
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#include <asm/dma.h>
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#include <asm/mmu_context.h>
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#include <asm/console.h>
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#include <asm/tlb.h>
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#include <asm/setup.h>
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#include <asm/sections.h>
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extern void die_if_kernel(char *,struct pt_regs *,long);
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static struct pcb_struct original_pcb;
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pgd_t *
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pgd_alloc(struct mm_struct *mm)
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{
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pgd_t *ret, *init;
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ret = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
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init = pgd_offset(&init_mm, 0UL);
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if (ret) {
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#ifdef CONFIG_ALPHA_LARGE_VMALLOC
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memcpy (ret + USER_PTRS_PER_PGD, init + USER_PTRS_PER_PGD,
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(PTRS_PER_PGD - USER_PTRS_PER_PGD - 1)*sizeof(pgd_t));
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#else
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pgd_val(ret[PTRS_PER_PGD-2]) = pgd_val(init[PTRS_PER_PGD-2]);
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#endif
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/* The last PGD entry is the VPTB self-map. */
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pgd_val(ret[PTRS_PER_PGD-1])
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= pte_val(mk_pte(virt_to_page(ret), PAGE_KERNEL));
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}
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return ret;
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}
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/*
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* BAD_PAGE is the page that is used for page faults when linux
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* is out-of-memory. Older versions of linux just did a
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* do_exit(), but using this instead means there is less risk
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* for a process dying in kernel mode, possibly leaving an inode
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* unused etc..
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*
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* BAD_PAGETABLE is the accompanying page-table: it is initialized
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* to point to BAD_PAGE entries.
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*
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* ZERO_PAGE is a special page that is used for zero-initialized
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* data and COW.
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*/
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pmd_t *
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__bad_pagetable(void)
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{
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memset((void *) EMPTY_PGT, 0, PAGE_SIZE);
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return (pmd_t *) EMPTY_PGT;
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}
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pte_t
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__bad_page(void)
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{
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memset((void *) EMPTY_PGE, 0, PAGE_SIZE);
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return pte_mkdirty(mk_pte(virt_to_page(EMPTY_PGE), PAGE_SHARED));
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}
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static inline unsigned long
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load_PCB(struct pcb_struct *pcb)
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{
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register unsigned long sp __asm__("$30");
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pcb->ksp = sp;
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return __reload_thread(pcb);
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}
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/* Set up initial PCB, VPTB, and other such nicities. */
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static inline void
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switch_to_system_map(void)
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{
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unsigned long newptbr;
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unsigned long original_pcb_ptr;
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/* Initialize the kernel's page tables. Linux puts the vptb in
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the last slot of the L1 page table. */
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memset(swapper_pg_dir, 0, PAGE_SIZE);
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newptbr = ((unsigned long) swapper_pg_dir - PAGE_OFFSET) >> PAGE_SHIFT;
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pgd_val(swapper_pg_dir[1023]) =
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(newptbr << 32) | pgprot_val(PAGE_KERNEL);
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/* Set the vptb. This is often done by the bootloader, but
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shouldn't be required. */
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if (hwrpb->vptb != 0xfffffffe00000000UL) {
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wrvptptr(0xfffffffe00000000UL);
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hwrpb->vptb = 0xfffffffe00000000UL;
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hwrpb_update_checksum(hwrpb);
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}
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/* Also set up the real kernel PCB while we're at it. */
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init_thread_info.pcb.ptbr = newptbr;
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init_thread_info.pcb.flags = 1; /* set FEN, clear everything else */
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original_pcb_ptr = load_PCB(&init_thread_info.pcb);
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tbia();
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/* Save off the contents of the original PCB so that we can
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restore the original console's page tables for a clean reboot.
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Note that the PCB is supposed to be a physical address, but
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since KSEG values also happen to work, folks get confused.
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Check this here. */
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if (original_pcb_ptr < PAGE_OFFSET) {
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original_pcb_ptr = (unsigned long)
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phys_to_virt(original_pcb_ptr);
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}
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original_pcb = *(struct pcb_struct *) original_pcb_ptr;
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}
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int callback_init_done;
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void * __init
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callback_init(void * kernel_end)
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{
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struct crb_struct * crb;
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pgd_t *pgd;
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pmd_t *pmd;
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void *two_pages;
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/* Starting at the HWRPB, locate the CRB. */
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crb = (struct crb_struct *)((char *)hwrpb + hwrpb->crb_offset);
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if (alpha_using_srm) {
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/* Tell the console whither it is to be remapped. */
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if (srm_fixup(VMALLOC_START, (unsigned long)hwrpb))
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__halt(); /* "We're boned." --Bender */
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/* Edit the procedure descriptors for DISPATCH and FIXUP. */
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crb->dispatch_va = (struct procdesc_struct *)
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(VMALLOC_START + (unsigned long)crb->dispatch_va
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- crb->map[0].va);
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crb->fixup_va = (struct procdesc_struct *)
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(VMALLOC_START + (unsigned long)crb->fixup_va
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- crb->map[0].va);
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}
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switch_to_system_map();
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/* Allocate one PGD and one PMD. In the case of SRM, we'll need
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these to actually remap the console. There is an assumption
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here that only one of each is needed, and this allows for 8MB.
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On systems with larger consoles, additional pages will be
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allocated as needed during the mapping process.
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In the case of not SRM, but not CONFIG_ALPHA_LARGE_VMALLOC,
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we need to allocate the PGD we use for vmalloc before we start
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forking other tasks. */
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two_pages = (void *)
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(((unsigned long)kernel_end + ~PAGE_MASK) & PAGE_MASK);
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kernel_end = two_pages + 2*PAGE_SIZE;
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memset(two_pages, 0, 2*PAGE_SIZE);
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pgd = pgd_offset_k(VMALLOC_START);
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pgd_set(pgd, (pmd_t *)two_pages);
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pmd = pmd_offset(pgd, VMALLOC_START);
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pmd_set(pmd, (pte_t *)(two_pages + PAGE_SIZE));
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if (alpha_using_srm) {
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static struct vm_struct console_remap_vm;
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unsigned long nr_pages = 0;
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unsigned long vaddr;
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unsigned long i, j;
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/* calculate needed size */
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for (i = 0; i < crb->map_entries; ++i)
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nr_pages += crb->map[i].count;
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/* register the vm area */
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console_remap_vm.flags = VM_ALLOC;
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console_remap_vm.size = nr_pages << PAGE_SHIFT;
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vm_area_register_early(&console_remap_vm, PAGE_SIZE);
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vaddr = (unsigned long)console_remap_vm.addr;
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/* Set up the third level PTEs and update the virtual
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addresses of the CRB entries. */
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for (i = 0; i < crb->map_entries; ++i) {
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unsigned long pfn = crb->map[i].pa >> PAGE_SHIFT;
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crb->map[i].va = vaddr;
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for (j = 0; j < crb->map[i].count; ++j) {
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/* Newer consoles (especially on larger
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systems) may require more pages of
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PTEs. Grab additional pages as needed. */
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if (pmd != pmd_offset(pgd, vaddr)) {
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memset(kernel_end, 0, PAGE_SIZE);
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pmd = pmd_offset(pgd, vaddr);
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pmd_set(pmd, (pte_t *)kernel_end);
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kernel_end += PAGE_SIZE;
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}
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set_pte(pte_offset_kernel(pmd, vaddr),
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pfn_pte(pfn, PAGE_KERNEL));
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pfn++;
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vaddr += PAGE_SIZE;
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}
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}
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}
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callback_init_done = 1;
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return kernel_end;
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}
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#ifndef CONFIG_DISCONTIGMEM
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/*
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* paging_init() sets up the memory map.
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*/
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void __init paging_init(void)
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{
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unsigned long zones_size[MAX_NR_ZONES] = {0, };
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unsigned long dma_pfn, high_pfn;
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dma_pfn = virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
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high_pfn = max_pfn = max_low_pfn;
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if (dma_pfn >= high_pfn)
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zones_size[ZONE_DMA] = high_pfn;
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else {
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zones_size[ZONE_DMA] = dma_pfn;
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zones_size[ZONE_NORMAL] = high_pfn - dma_pfn;
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}
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/* Initialize mem_map[]. */
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free_area_init(zones_size);
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/* Initialize the kernel's ZERO_PGE. */
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memset((void *)ZERO_PGE, 0, PAGE_SIZE);
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}
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#endif /* CONFIG_DISCONTIGMEM */
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#if defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_SRM)
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void
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srm_paging_stop (void)
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{
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/* Move the vptb back to where the SRM console expects it. */
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swapper_pg_dir[1] = swapper_pg_dir[1023];
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tbia();
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wrvptptr(0x200000000UL);
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hwrpb->vptb = 0x200000000UL;
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hwrpb_update_checksum(hwrpb);
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/* Reload the page tables that the console had in use. */
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load_PCB(&original_pcb);
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tbia();
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}
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#endif
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void __init
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mem_init(void)
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{
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set_max_mapnr(max_low_pfn);
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high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
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memblock_free_all();
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mem_init_print_info(NULL);
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}
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