mirror of
https://github.com/torvalds/linux
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d5f17ee964
This patch implements handling of STRICT_KERNEL_RWX with large TLBs directly in the TLB miss handlers. To do so, etext and sinittext are aligned on 512kB boundaries and the miss handlers use 512kB pages instead of 8Mb pages for addresses close to the boundaries. It sets RO PP flags for addresses under sinittext. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
184 lines
4.7 KiB
C
184 lines
4.7 KiB
C
/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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* PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/module.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/mm.h>
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#include <linux/stddef.h>
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#include <linux/init.h>
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#include <linux/highmem.h>
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#include <linux/initrd.h>
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#include <linux/pagemap.h>
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#include <linux/memblock.h>
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#include <linux/gfp.h>
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#include <linux/slab.h>
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#include <linux/hugetlb.h>
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#include <asm/pgalloc.h>
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#include <asm/prom.h>
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#include <asm/io.h>
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#include <asm/pgtable.h>
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#include <asm/mmu.h>
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#include <asm/smp.h>
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#include <asm/machdep.h>
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#include <asm/btext.h>
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#include <asm/tlb.h>
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#include <asm/sections.h>
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#include <asm/hugetlb.h>
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#include "mmu_decl.h"
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#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
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/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
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#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
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#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
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#endif
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#endif
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#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
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phys_addr_t total_memory;
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phys_addr_t total_lowmem;
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phys_addr_t memstart_addr = (phys_addr_t)~0ull;
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EXPORT_SYMBOL(memstart_addr);
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phys_addr_t kernstart_addr;
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EXPORT_SYMBOL(kernstart_addr);
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#ifdef CONFIG_RELOCATABLE
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/* Used in __va()/__pa() */
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long long virt_phys_offset;
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EXPORT_SYMBOL(virt_phys_offset);
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#endif
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phys_addr_t lowmem_end_addr;
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int boot_mapsize;
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#ifdef CONFIG_PPC_PMAC
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unsigned long agp_special_page;
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EXPORT_SYMBOL(agp_special_page);
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#endif
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void MMU_init(void);
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/*
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* this tells the system to map all of ram with the segregs
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* (i.e. page tables) instead of the bats.
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* -- Cort
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*/
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int __map_without_bats;
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int __map_without_ltlbs;
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/* max amount of low RAM to map in */
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unsigned long __max_low_memory = MAX_LOW_MEM;
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/*
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* Check for command-line options that affect what MMU_init will do.
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*/
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static void __init MMU_setup(void)
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{
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/* Check for nobats option (used in mapin_ram). */
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if (strstr(boot_command_line, "nobats")) {
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__map_without_bats = 1;
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}
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if (strstr(boot_command_line, "noltlbs")) {
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__map_without_ltlbs = 1;
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}
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if (debug_pagealloc_enabled()) {
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__map_without_bats = 1;
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__map_without_ltlbs = 1;
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}
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if (strict_kernel_rwx_enabled() && !IS_ENABLED(CONFIG_PPC_8xx))
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__map_without_ltlbs = 1;
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}
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/*
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* MMU_init sets up the basic memory mappings for the kernel,
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* including both RAM and possibly some I/O regions,
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* and sets up the page tables and the MMU hardware ready to go.
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*/
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void __init MMU_init(void)
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{
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if (ppc_md.progress)
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ppc_md.progress("MMU:enter", 0x111);
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/* parse args from command line */
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MMU_setup();
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/*
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* Reserve gigantic pages for hugetlb. This MUST occur before
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* lowmem_end_addr is initialized below.
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*/
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if (memblock.memory.cnt > 1) {
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#ifndef CONFIG_WII
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memblock_enforce_memory_limit(memblock.memory.regions[0].size);
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pr_warn("Only using first contiguous memory region\n");
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#else
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wii_memory_fixups();
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#endif
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}
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total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
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lowmem_end_addr = memstart_addr + total_lowmem;
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#ifdef CONFIG_FSL_BOOKE
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/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
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* entries, so we need to adjust lowmem to match the amount we can map
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* in the fixed entries */
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adjust_total_lowmem();
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#endif /* CONFIG_FSL_BOOKE */
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if (total_lowmem > __max_low_memory) {
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total_lowmem = __max_low_memory;
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lowmem_end_addr = memstart_addr + total_lowmem;
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#ifndef CONFIG_HIGHMEM
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total_memory = total_lowmem;
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memblock_enforce_memory_limit(total_lowmem);
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#endif /* CONFIG_HIGHMEM */
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}
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/* Initialize the MMU hardware */
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if (ppc_md.progress)
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ppc_md.progress("MMU:hw init", 0x300);
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MMU_init_hw();
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/* Map in all of RAM starting at KERNELBASE */
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if (ppc_md.progress)
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ppc_md.progress("MMU:mapin", 0x301);
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mapin_ram();
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/* Initialize early top-down ioremap allocator */
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ioremap_bot = IOREMAP_TOP;
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if (ppc_md.progress)
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ppc_md.progress("MMU:exit", 0x211);
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/* From now on, btext is no longer BAT mapped if it was at all */
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#ifdef CONFIG_BOOTX_TEXT
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btext_unmap();
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#endif
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/* Shortly after that, the entire linear mapping will be available */
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memblock_set_current_limit(lowmem_end_addr);
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}
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