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-rw-r--r--arch/powerpc/mm/init.c581
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diff --git a/arch/powerpc/mm/init.c b/arch/powerpc/mm/init.c
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+/*
+ * PowerPC version
+ * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
+ * and Cort Dougan (PReP) (cort@cs.nmt.edu)
+ * Copyright (C) 1996 Paul Mackerras
+ * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
+ * PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
+ *
+ * Derived from "arch/i386/mm/init.c"
+ * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/initrd.h>
+#include <linux/pagemap.h>
+
+#include <asm/pgalloc.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+#include <asm/btext.h>
+#include <asm/tlb.h>
+#include <asm/bootinfo.h>
+#include <asm/prom.h>
+
+#include "mem_pieces.h"
+#include "mmu_decl.h"
+
+#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
+/* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */
+#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE))
+#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
+#endif
+#endif
+#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
+
+DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+unsigned long total_memory;
+unsigned long total_lowmem;
+
+unsigned long ppc_memstart;
+unsigned long ppc_memoffset = PAGE_OFFSET;
+
+int mem_init_done;
+int init_bootmem_done;
+int boot_mapsize;
+#ifdef CONFIG_PPC_PMAC
+unsigned long agp_special_page;
+#endif
+
+extern char _end[];
+extern char etext[], _stext[];
+extern char __init_begin, __init_end;
+
+#ifdef CONFIG_HIGHMEM
+pte_t *kmap_pte;
+pgprot_t kmap_prot;
+
+EXPORT_SYMBOL(kmap_prot);
+EXPORT_SYMBOL(kmap_pte);
+#endif
+
+void MMU_init(void);
+void set_phys_avail(unsigned long total_ram);
+
+/* XXX should be in current.h -- paulus */
+extern struct task_struct *current_set[NR_CPUS];
+
+char *klimit = _end;
+struct mem_pieces phys_avail;
+struct device_node *memory_node;
+
+/*
+ * this tells the system to map all of ram with the segregs
+ * (i.e. page tables) instead of the bats.
+ * -- Cort
+ */
+int __map_without_bats;
+int __map_without_ltlbs;
+
+/* max amount of RAM to use */
+unsigned long __max_memory;
+/* max amount of low RAM to map in */
+unsigned long __max_low_memory = MAX_LOW_MEM;
+
+/*
+ * Read in a property describing some pieces of memory.
+ */
+static int __init get_mem_prop(char *name, struct mem_pieces *mp)
+{
+ struct reg_property *rp;
+ int i, s;
+ unsigned int *ip;
+ int nac = prom_n_addr_cells(memory_node);
+ int nsc = prom_n_size_cells(memory_node);
+
+ ip = (unsigned int *) get_property(memory_node, name, &s);
+ if (ip == NULL) {
+ printk(KERN_ERR "error: couldn't get %s property on /memory\n",
+ name);
+ return 0;
+ }
+ s /= (nsc + nac) * 4;
+ rp = mp->regions;
+ for (i = 0; i < s; ++i, ip += nac+nsc) {
+ if (nac >= 2 && ip[nac-2] != 0)
+ continue;
+ rp->address = ip[nac-1];
+ if (nsc >= 2 && ip[nac+nsc-2] != 0)
+ rp->size = ~0U;
+ else
+ rp->size = ip[nac+nsc-1];
+ ++rp;
+ }
+ mp->n_regions = rp - mp->regions;
+
+ /* Make sure the pieces are sorted. */
+ mem_pieces_sort(mp);
+ mem_pieces_coalesce(mp);
+ return 1;
+}
+
+/*
+ * Collect information about physical RAM and which pieces are
+ * already in use from the device tree.
+ */
+unsigned long __init find_end_of_memory(void)
+{
+ unsigned long a, total;
+ struct mem_pieces phys_mem;
+
+ /*
+ * Find out where physical memory is, and check that it
+ * starts at 0 and is contiguous. It seems that RAM is
+ * always physically contiguous on Power Macintoshes.
+ *
+ * Supporting discontiguous physical memory isn't hard,
+ * it just makes the virtual <-> physical mapping functions
+ * more complicated (or else you end up wasting space
+ * in mem_map).
+ */
+ memory_node = find_devices("memory");
+ if (memory_node == NULL || !get_mem_prop("reg", &phys_mem)
+ || phys_mem.n_regions == 0)
+ panic("No RAM??");
+ a = phys_mem.regions[0].address;
+ if (a != 0)
+ panic("RAM doesn't start at physical address 0");
+ total = phys_mem.regions[0].size;
+
+ if (phys_mem.n_regions > 1) {
+ printk("RAM starting at 0x%x is not contiguous\n",
+ phys_mem.regions[1].address);
+ printk("Using RAM from 0 to 0x%lx\n", total-1);
+ }
+
+ return total;
+}
+
+/*
+ * Check for command-line options that affect what MMU_init will do.
+ */
+void MMU_setup(void)
+{
+ /* Check for nobats option (used in mapin_ram). */
+ if (strstr(cmd_line, "nobats")) {
+ __map_without_bats = 1;
+ }
+
+ if (strstr(cmd_line, "noltlbs")) {
+ __map_without_ltlbs = 1;
+ }
+
+ /* Look for mem= option on command line */
+ if (strstr(cmd_line, "mem=")) {
+ char *p, *q;
+ unsigned long maxmem = 0;
+
+ for (q = cmd_line; (p = strstr(q, "mem=")) != 0; ) {
+ q = p + 4;
+ if (p > cmd_line && p[-1] != ' ')
+ continue;
+ maxmem = simple_strtoul(q, &q, 0);
+ if (*q == 'k' || *q == 'K') {
+ maxmem <<= 10;
+ ++q;
+ } else if (*q == 'm' || *q == 'M') {
+ maxmem <<= 20;
+ ++q;
+ }
+ }
+ __max_memory = maxmem;
+ }
+}
+
+/*
+ * MMU_init sets up the basic memory mappings for the kernel,
+ * including both RAM and possibly some I/O regions,
+ * and sets up the page tables and the MMU hardware ready to go.
+ */
+void __init MMU_init(void)
+{
+ if (ppc_md.progress)
+ ppc_md.progress("MMU:enter", 0x111);
+
+ /* parse args from command line */
+ MMU_setup();
+
+ /*
+ * Figure out how much memory we have, how much
+ * is lowmem, and how much is highmem. If we were
+ * passed the total memory size from the bootloader,
+ * just use it.
+ */
+ if (boot_mem_size)
+ total_memory = boot_mem_size;
+ else
+ total_memory = ppc_md.find_end_of_memory();
+
+ if (__max_memory && total_memory > __max_memory)
+ total_memory = __max_memory;
+ total_lowmem = total_memory;
+#ifdef CONFIG_FSL_BOOKE
+ /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
+ * entries, so we need to adjust lowmem to match the amount we can map
+ * in the fixed entries */
+ adjust_total_lowmem();
+#endif /* CONFIG_FSL_BOOKE */
+ if (total_lowmem > __max_low_memory) {
+ total_lowmem = __max_low_memory;
+#ifndef CONFIG_HIGHMEM
+ total_memory = total_lowmem;
+#endif /* CONFIG_HIGHMEM */
+ }
+ set_phys_avail(total_lowmem);
+
+ /* Initialize the MMU hardware */
+ if (ppc_md.progress)
+ ppc_md.progress("MMU:hw init", 0x300);
+ MMU_init_hw();
+
+ /* Map in all of RAM starting at KERNELBASE */
+ if (ppc_md.progress)
+ ppc_md.progress("MMU:mapin", 0x301);
+ mapin_ram();
+
+#ifdef CONFIG_HIGHMEM
+ ioremap_base = PKMAP_BASE;
+#else
+ ioremap_base = 0xfe000000UL; /* for now, could be 0xfffff000 */
+#endif /* CONFIG_HIGHMEM */
+ ioremap_bot = ioremap_base;
+
+ /* Map in I/O resources */
+ if (ppc_md.progress)
+ ppc_md.progress("MMU:setio", 0x302);
+ if (ppc_md.setup_io_mappings)
+ ppc_md.setup_io_mappings();
+
+ /* Initialize the context management stuff */
+ mmu_context_init();
+
+ if (ppc_md.progress)
+ ppc_md.progress("MMU:exit", 0x211);
+
+#ifdef CONFIG_BOOTX_TEXT
+ /* By default, we are no longer mapped */
+ boot_text_mapped = 0;
+ /* Must be done last, or ppc_md.progress will die. */
+ map_boot_text();
+#endif
+}
+
+/* This is only called until mem_init is done. */
+void __init *early_get_page(void)
+{
+ void *p;
+
+ if (init_bootmem_done) {
+ p = alloc_bootmem_pages(PAGE_SIZE);
+ } else {
+ p = mem_pieces_find(PAGE_SIZE, PAGE_SIZE);
+ }
+ return p;
+}
+
+/* Free up now-unused memory */
+static void free_sec(unsigned long start, unsigned long end, const char *name)
+{
+ unsigned long cnt = 0;
+
+ while (start < end) {
+ ClearPageReserved(virt_to_page(start));
+ set_page_count(virt_to_page(start), 1);
+ free_page(start);
+ cnt++;
+ start += PAGE_SIZE;
+ }
+ if (cnt) {
+ printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
+ totalram_pages += cnt;
+ }
+}
+
+void free_initmem(void)
+{
+#define FREESEC(TYPE) \
+ free_sec((unsigned long)(&__ ## TYPE ## _begin), \
+ (unsigned long)(&__ ## TYPE ## _end), \
+ #TYPE);
+
+ printk ("Freeing unused kernel memory:");
+ FREESEC(init);
+ printk("\n");
+ ppc_md.progress = NULL;
+#undef FREESEC
+}
+
+#ifdef CONFIG_BLK_DEV_INITRD
+void free_initrd_mem(unsigned long start, unsigned long end)
+{
+ if (start < end)
+ printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
+ for (; start < end; start += PAGE_SIZE) {
+ ClearPageReserved(virt_to_page(start));
+ set_page_count(virt_to_page(start), 1);
+ free_page(start);
+ totalram_pages++;
+ }
+}
+#endif
+
+/*
+ * Initialize the bootmem system and give it all the memory we
+ * have available.
+ */
+void __init do_init_bootmem(void)
+{
+ unsigned long start, size;
+ int i;
+
+ /*
+ * Find an area to use for the bootmem bitmap.
+ * We look for the first area which is at least
+ * 128kB in length (128kB is enough for a bitmap
+ * for 4GB of memory, using 4kB pages), plus 1 page
+ * (in case the address isn't page-aligned).
+ */
+ start = 0;
+ size = 0;
+ for (i = 0; i < phys_avail.n_regions; ++i) {
+ unsigned long a = phys_avail.regions[i].address;
+ unsigned long s = phys_avail.regions[i].size;
+ if (s <= size)
+ continue;
+ start = a;
+ size = s;
+ if (s >= 33 * PAGE_SIZE)
+ break;
+ }
+ start = PAGE_ALIGN(start);
+
+ min_low_pfn = start >> PAGE_SHIFT;
+ max_low_pfn = (PPC_MEMSTART + total_lowmem) >> PAGE_SHIFT;
+ max_pfn = (PPC_MEMSTART + total_memory) >> PAGE_SHIFT;
+ boot_mapsize = init_bootmem_node(&contig_page_data, min_low_pfn,
+ PPC_MEMSTART >> PAGE_SHIFT,
+ max_low_pfn);
+
+ /* remove the bootmem bitmap from the available memory */
+ mem_pieces_remove(&phys_avail, start, boot_mapsize, 1);
+
+ /* add everything in phys_avail into the bootmem map */
+ for (i = 0; i < phys_avail.n_regions; ++i)
+ free_bootmem(phys_avail.regions[i].address,
+ phys_avail.regions[i].size);
+
+ init_bootmem_done = 1;
+}
+
+/*
+ * paging_init() sets up the page tables - in fact we've already done this.
+ */
+void __init paging_init(void)
+{
+ unsigned long zones_size[MAX_NR_ZONES], i;
+
+#ifdef CONFIG_HIGHMEM
+ map_page(PKMAP_BASE, 0, 0); /* XXX gross */
+ pkmap_page_table = pte_offset_kernel(pmd_offset(pgd_offset_k
+ (PKMAP_BASE), PKMAP_BASE), PKMAP_BASE);
+ map_page(KMAP_FIX_BEGIN, 0, 0); /* XXX gross */
+ kmap_pte = pte_offset_kernel(pmd_offset(pgd_offset_k
+ (KMAP_FIX_BEGIN), KMAP_FIX_BEGIN), KMAP_FIX_BEGIN);
+ kmap_prot = PAGE_KERNEL;
+#endif /* CONFIG_HIGHMEM */
+
+ /*
+ * All pages are DMA-able so we put them all in the DMA zone.
+ */
+ zones_size[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
+ for (i = 1; i < MAX_NR_ZONES; i++)
+ zones_size[i] = 0;
+
+#ifdef CONFIG_HIGHMEM
+ zones_size[ZONE_HIGHMEM] = (total_memory - total_lowmem) >> PAGE_SHIFT;
+#endif /* CONFIG_HIGHMEM */
+
+ free_area_init(zones_size);
+}
+
+void __init mem_init(void)
+{
+ unsigned long addr;
+ int codepages = 0;
+ int datapages = 0;
+ int initpages = 0;
+#ifdef CONFIG_HIGHMEM
+ unsigned long highmem_mapnr;
+
+ highmem_mapnr = total_lowmem >> PAGE_SHIFT;
+#endif /* CONFIG_HIGHMEM */
+ max_mapnr = total_memory >> PAGE_SHIFT;
+
+ high_memory = (void *) __va(PPC_MEMSTART + total_lowmem);
+ num_physpages = max_mapnr; /* RAM is assumed contiguous */
+
+ totalram_pages += free_all_bootmem();
+
+#ifdef CONFIG_BLK_DEV_INITRD
+ /* if we are booted from BootX with an initial ramdisk,
+ make sure the ramdisk pages aren't reserved. */
+ if (initrd_start) {
+ for (addr = initrd_start; addr < initrd_end; addr += PAGE_SIZE)
+ ClearPageReserved(virt_to_page(addr));
+ }
+#endif /* CONFIG_BLK_DEV_INITRD */
+
+#ifdef CONFIG_PPC_OF
+ /* mark the RTAS pages as reserved */
+ if ( rtas_data )
+ for (addr = (ulong)__va(rtas_data);
+ addr < PAGE_ALIGN((ulong)__va(rtas_data)+rtas_size) ;
+ addr += PAGE_SIZE)
+ SetPageReserved(virt_to_page(addr));
+#endif
+#ifdef CONFIG_PPC_PMAC
+ if (agp_special_page)
+ SetPageReserved(virt_to_page(agp_special_page));
+#endif
+ for (addr = PAGE_OFFSET; addr < (unsigned long)high_memory;
+ addr += PAGE_SIZE) {
+ if (!PageReserved(virt_to_page(addr)))
+ continue;
+ if (addr < (ulong) etext)
+ codepages++;
+ else if (addr >= (unsigned long)&__init_begin
+ && addr < (unsigned long)&__init_end)
+ initpages++;
+ else if (addr < (ulong) klimit)
+ datapages++;
+ }
+
+#ifdef CONFIG_HIGHMEM
+ {
+ unsigned long pfn;
+
+ for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
+ struct page *page = mem_map + pfn;
+
+ ClearPageReserved(page);
+ set_page_count(page, 1);
+ __free_page(page);
+ totalhigh_pages++;
+ }
+ totalram_pages += totalhigh_pages;
+ }
+#endif /* CONFIG_HIGHMEM */
+
+ printk("Memory: %luk available (%dk kernel code, %dk data, %dk init, %ldk highmem)\n",
+ (unsigned long)nr_free_pages()<< (PAGE_SHIFT-10),
+ codepages<< (PAGE_SHIFT-10), datapages<< (PAGE_SHIFT-10),
+ initpages<< (PAGE_SHIFT-10),
+ (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10)));
+
+#ifdef CONFIG_PPC_PMAC
+ if (agp_special_page)
+ printk(KERN_INFO "AGP special page: 0x%08lx\n", agp_special_page);
+#endif
+
+ mem_init_done = 1;
+}
+
+/*
+ * Set phys_avail to the amount of physical memory,
+ * less the kernel text/data/bss.
+ */
+void __init
+set_phys_avail(unsigned long total_memory)
+{
+ unsigned long kstart, ksize;
+
+ /*
+ * Initially, available physical memory is equivalent to all
+ * physical memory.
+ */
+
+ phys_avail.regions[0].address = PPC_MEMSTART;
+ phys_avail.regions[0].size = total_memory;
+ phys_avail.n_regions = 1;
+
+ /*
+ * Map out the kernel text/data/bss from the available physical
+ * memory.
+ */
+
+ kstart = __pa(_stext); /* should be 0 */
+ ksize = PAGE_ALIGN(klimit - _stext);
+
+ mem_pieces_remove(&phys_avail, kstart, ksize, 0);
+ mem_pieces_remove(&phys_avail, 0, 0x4000, 0);
+
+#if defined(CONFIG_BLK_DEV_INITRD)
+ /* Remove the init RAM disk from the available memory. */
+ if (initrd_start) {
+ mem_pieces_remove(&phys_avail, __pa(initrd_start),
+ initrd_end - initrd_start, 1);
+ }
+#endif /* CONFIG_BLK_DEV_INITRD */
+#ifdef CONFIG_PPC_OF
+ /* remove the RTAS pages from the available memory */
+ if (rtas_data)
+ mem_pieces_remove(&phys_avail, rtas_data, rtas_size, 1);
+#endif
+#ifdef CONFIG_PPC_PMAC
+ /* Because of some uninorth weirdness, we need a page of
+ * memory as high as possible (it must be outside of the
+ * bus address seen as the AGP aperture). It will be used
+ * by the r128 DRM driver
+ *
+ * FIXME: We need to make sure that page doesn't overlap any of the\
+ * above. This could be done by improving mem_pieces_find to be able
+ * to do a backward search from the end of the list.
+ */
+ if (_machine == _MACH_Pmac && find_devices("uni-north-agp")) {
+ agp_special_page = (total_memory - PAGE_SIZE);
+ mem_pieces_remove(&phys_avail, agp_special_page, PAGE_SIZE, 0);
+ agp_special_page = (unsigned long)__va(agp_special_page);
+ }
+#endif /* CONFIG_PPC_PMAC */
+}
+
+/* Mark some memory as reserved by removing it from phys_avail. */
+void __init reserve_phys_mem(unsigned long start, unsigned long size)
+{
+ mem_pieces_remove(&phys_avail, start, size, 1);
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.