init.c

  1/*
  2 * Copyright (C) 2007-2008 Michal Simek <monstr@monstr.eu>
  3 * Copyright (C) 2006 Atmark Techno, Inc.
  4 *
  5 * This file is subject to the terms and conditions of the GNU General Public
  6 * License. See the file "COPYING" in the main directory of this archive
  7 * for more details.
  8 */
  9
 10#include <linux/dma-map-ops.h>
 11#include <linux/memblock.h>
 12#include <linux/init.h>
 13#include <linux/kernel.h>
 14#include <linux/mm.h> /* mem_init */
 15#include <linux/initrd.h>
 16#include <linux/of_fdt.h>
 17#include <linux/pagemap.h>
 18#include <linux/pfn.h>
 19#include <linux/slab.h>
 20#include <linux/swap.h>
 21#include <linux/export.h>
 22
 23#include <asm/page.h>
 24#include <asm/mmu_context.h>
 25#include <asm/pgalloc.h>
 26#include <asm/sections.h>
 27#include <asm/tlb.h>
 28#include <asm/fixmap.h>
 29
 30/* Use for MMU and noMMU because of PCI generic code */
 31int mem_init_done;
 32
 33char *klimit = _end;
 34
 35/*
 36 * Initialize the bootmem system and give it all the memory we
 37 * have available.
 38 */
 39unsigned long memory_start;
 40EXPORT_SYMBOL(memory_start);
 41unsigned long memory_size;
 42EXPORT_SYMBOL(memory_size);
 43unsigned long lowmem_size;
 44
 45EXPORT_SYMBOL(min_low_pfn);
 46EXPORT_SYMBOL(max_low_pfn);
 47
 48#ifdef CONFIG_HIGHMEM
 49static void __init highmem_init(void)
 50{
 51	pr_debug("%x\n", (u32)PKMAP_BASE);
 52	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
 53	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
 54}
 55#endif /* CONFIG_HIGHMEM */
 56
 57/*
 58 * paging_init() sets up the page tables - in fact we've already done this.
 59 */
 60static void __init paging_init(void)
 61{
 62	unsigned long zones_size[MAX_NR_ZONES];
 63	int idx;
 64
 65	/* Setup fixmaps */
 66	for (idx = 0; idx < __end_of_fixed_addresses; idx++)
 67		clear_fixmap(idx);
 68
 69	/* Clean every zones */
 70	memset(zones_size, 0, sizeof(zones_size));
 71
 72#ifdef CONFIG_HIGHMEM
 73	highmem_init();
 74
 75	zones_size[ZONE_DMA] = max_low_pfn;
 76	zones_size[ZONE_HIGHMEM] = max_pfn;
 77#else
 78	zones_size[ZONE_DMA] = max_pfn;
 79#endif
 80
 81	/* We don't have holes in memory map */
 82	free_area_init(zones_size);
 83}
 84
 85void __init setup_memory(void)
 86{
 87	/*
 88	 * Kernel:
 89	 * start: base phys address of kernel - page align
 90	 * end: base phys address of kernel - page align
 91	 *
 92	 * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
 93	 * max_low_pfn
 94	 */
 95
 96	/* memory start is from the kernel end (aligned) to higher addr */
 97	min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
 98	max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
 99	max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;
100
101	pr_info("%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
102	pr_info("%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);
103	pr_info("%s: max_pfn: %#lx\n", __func__, max_pfn);
104
105	paging_init();
106}
107
108void __init mem_init(void)
109{
110	mem_init_done = 1;
111}
112
113int page_is_ram(unsigned long pfn)
114{
115	return pfn < max_low_pfn;
116}
117
118/*
119 * Check for command-line options that affect what MMU_init will do.
120 */
121static void __init mm_cmdline_setup(void)
122{
123	unsigned long maxmem = 0;
124	char *p = cmd_line;
125
126	/* Look for mem= option on command line */
127	p = strstr(cmd_line, "mem=");
128	if (p) {
129		p += 4;
130		maxmem = memparse(p, &p);
131		if (maxmem && memory_size > maxmem) {
132			memory_size = maxmem;
133			memblock.memory.regions[0].size = memory_size;
134		}
135	}
136}
137
138/*
139 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
140 */
141static void __init mmu_init_hw(void)
142{
143	/*
144	 * The Zone Protection Register (ZPR) defines how protection will
145	 * be applied to every page which is a member of a given zone. At
146	 * present, we utilize only two of the zones.
147	 * The zone index bits (of ZSEL) in the PTE are used for software
148	 * indicators, except the LSB.  For user access, zone 1 is used,
149	 * for kernel access, zone 0 is used.  We set all but zone 1
150	 * to zero, allowing only kernel access as indicated in the PTE.
151	 * For zone 1, we set a 01 binary (a value of 10 will not work)
152	 * to allow user access as indicated in the PTE.  This also allows
153	 * kernel access as indicated in the PTE.
154	 */
155	__asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
156			"mts rzpr, r11;"
157			: : : "r11");
158}
159
160/*
161 * MMU_init sets up the basic memory mappings for the kernel,
162 * including both RAM and possibly some I/O regions,
163 * and sets up the page tables and the MMU hardware ready to go.
164 */
165
166/* called from head.S */
167asmlinkage void __init mmu_init(void)
168{
169	unsigned int kstart, ksize;
170
171	if ((u32) memblock.memory.regions[0].size < 0x400000) {
172		pr_emerg("Memory must be greater than 4MB\n");
173		machine_restart(NULL);
174	}
175
176	if ((u32) memblock.memory.regions[0].size < kernel_tlb) {
177		pr_emerg("Kernel size is greater than memory node\n");
178		machine_restart(NULL);
179	}
180
181	/* Find main memory where the kernel is */
182	memory_start = (u32) memblock.memory.regions[0].base;
183	lowmem_size = memory_size = (u32) memblock.memory.regions[0].size;
184
185	if (lowmem_size > CONFIG_LOWMEM_SIZE) {
186		lowmem_size = CONFIG_LOWMEM_SIZE;
187#ifndef CONFIG_HIGHMEM
188		memory_size = lowmem_size;
189#endif
190	}
191
192	mm_cmdline_setup(); /* FIXME parse args from command line - not used */
193
194	/*
195	 * Map out the kernel text/data/bss from the available physical
196	 * memory.
197	 */
198	kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
199	/* kernel size */
200	ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
201	memblock_reserve(kstart, ksize);
202
203#if defined(CONFIG_BLK_DEV_INITRD)
204	/* Remove the init RAM disk from the available memory. */
205	if (initrd_start) {
206		unsigned long size;
207		size = initrd_end - initrd_start;
208		memblock_reserve(__virt_to_phys(initrd_start), size);
209	}
210#endif /* CONFIG_BLK_DEV_INITRD */
211
212	/* Initialize the MMU hardware */
213	mmu_init_hw();
214
215	/* Map in all of RAM starting at CONFIG_KERNEL_START */
216	mapin_ram();
217
218	/* Extend vmalloc and ioremap area as big as possible */
219#ifdef CONFIG_HIGHMEM
220	ioremap_base = ioremap_bot = PKMAP_BASE;
221#else
222	ioremap_base = ioremap_bot = FIXADDR_START;
223#endif
224
225	/* Initialize the context management stuff */
226	mmu_context_init();
227
228	/* Shortly after that, the entire linear mapping will be available */
229	/* This will also cause that unflatten device tree will be allocated
230	 * inside 768MB limit */
231	memblock_set_current_limit(memory_start + lowmem_size - 1);
232
233	parse_early_param();
234
235	early_init_fdt_scan_reserved_mem();
236
237	/* CMA initialization */
238	dma_contiguous_reserve(memory_start + lowmem_size - 1);
239
240	memblock_dump_all();
241}
242
243static const pgprot_t protection_map[16] = {
244	[VM_NONE]					= PAGE_NONE,
245	[VM_READ]					= PAGE_READONLY_X,
246	[VM_WRITE]					= PAGE_COPY,
247	[VM_WRITE | VM_READ]				= PAGE_COPY_X,
248	[VM_EXEC]					= PAGE_READONLY,
249	[VM_EXEC | VM_READ]				= PAGE_READONLY_X,
250	[VM_EXEC | VM_WRITE]				= PAGE_COPY,
251	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_X,
252	[VM_SHARED]					= PAGE_NONE,
253	[VM_SHARED | VM_READ]				= PAGE_READONLY_X,
254	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
255	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED_X,
256	[VM_SHARED | VM_EXEC]				= PAGE_READONLY,
257	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY_X,
258	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED,
259	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_X
260};
261DECLARE_VM_GET_PAGE_PROT