Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
/*
 * Copyright (C) 2007-2008 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2006 Atmark Techno, Inc.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */

#include <linux/bootmem.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/mm.h> /* mem_init */
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/pfn.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/export.h>

#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>

/* Use for MMU and noMMU because of PCI generic code */
int mem_init_done;

#ifndef CONFIG_MMU
unsigned int __page_offset;
EXPORT_SYMBOL(__page_offset);

#else
static int init_bootmem_done;
#endif /* CONFIG_MMU */

char *klimit = _end;

/*
 * Initialize the bootmem system and give it all the memory we
 * have available.
 */
unsigned long memory_start;
EXPORT_SYMBOL(memory_start);
unsigned long memory_size;
EXPORT_SYMBOL(memory_size);
unsigned long lowmem_size;

#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
EXPORT_SYMBOL(kmap_pte);
pgprot_t kmap_prot;
EXPORT_SYMBOL(kmap_prot);

static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
	return pte_offset_kernel(pmd_offset(pgd_offset_k(vaddr),
			vaddr), vaddr);
}

static void __init highmem_init(void)
{
	pr_debug("%x\n", (u32)PKMAP_BASE);
	map_page(PKMAP_BASE, 0, 0);	/* XXX gross */
	pkmap_page_table = virt_to_kpte(PKMAP_BASE);

	kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
	kmap_prot = PAGE_KERNEL;
}

static unsigned long highmem_setup(void)
{
	unsigned long pfn;
	unsigned long reservedpages = 0;

	for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) {
		struct page *page = pfn_to_page(pfn);

		/* FIXME not sure about */
		if (memblock_is_reserved(pfn << PAGE_SHIFT))
			continue;
		free_highmem_page(page);
		reservedpages++;
	}
	pr_info("High memory: %luk\n",
					totalhigh_pages << (PAGE_SHIFT-10));

	return reservedpages;
}
#endif /* CONFIG_HIGHMEM */

/*
 * paging_init() sets up the page tables - in fact we've already done this.
 */
static void __init paging_init(void)
{
	unsigned long zones_size[MAX_NR_ZONES];
#ifdef CONFIG_MMU
	int idx;

	/* Setup fixmaps */
	for (idx = 0; idx < __end_of_fixed_addresses; idx++)
		clear_fixmap(idx);
#endif

	/* Clean every zones */
	memset(zones_size, 0, sizeof(zones_size));

#ifdef CONFIG_HIGHMEM
	highmem_init();

	zones_size[ZONE_DMA] = max_low_pfn;
	zones_size[ZONE_HIGHMEM] = max_pfn;
#else
	zones_size[ZONE_DMA] = max_pfn;
#endif

	/* We don't have holes in memory map */
	free_area_init_nodes(zones_size);
}

void __init setup_memory(void)
{
	unsigned long map_size;
	struct memblock_region *reg;

#ifndef CONFIG_MMU
	u32 kernel_align_start, kernel_align_size;

	/* Find main memory where is the kernel */
	for_each_memblock(memory, reg) {
		memory_start = (u32)reg->base;
		lowmem_size = reg->size;
		if ((memory_start <= (u32)_text) &&
			((u32)_text <= (memory_start + lowmem_size - 1))) {
			memory_size = lowmem_size;
			PAGE_OFFSET = memory_start;
			pr_info("%s: Main mem: 0x%x, size 0x%08x\n",
				__func__, (u32) memory_start,
					(u32) memory_size);
			break;
		}
	}

	if (!memory_start || !memory_size) {
		panic("%s: Missing memory setting 0x%08x, size=0x%08x\n",
			__func__, (u32) memory_start, (u32) memory_size);
	}

	/* reservation of region where is the kernel */
	kernel_align_start = PAGE_DOWN((u32)_text);
	/* ALIGN can be remove because _end in vmlinux.lds.S is align */
	kernel_align_size = PAGE_UP((u32)klimit) - kernel_align_start;
	pr_info("%s: kernel addr:0x%08x-0x%08x size=0x%08x\n",
		__func__, kernel_align_start, kernel_align_start
			+ kernel_align_size, kernel_align_size);
	memblock_reserve(kernel_align_start, kernel_align_size);
#endif
	/*
	 * Kernel:
	 * start: base phys address of kernel - page align
	 * end: base phys address of kernel - page align
	 *
	 * min_low_pfn - the first page (mm/bootmem.c - node_boot_start)
	 * max_low_pfn
	 * max_mapnr - the first unused page (mm/bootmem.c - node_low_pfn)
	 * num_physpages - number of all pages
	 */

	/* memory start is from the kernel end (aligned) to higher addr */
	min_low_pfn = memory_start >> PAGE_SHIFT; /* minimum for allocation */
	/* RAM is assumed contiguous */
	num_physpages = max_mapnr = memory_size >> PAGE_SHIFT;
	max_low_pfn = ((u64)memory_start + (u64)lowmem_size) >> PAGE_SHIFT;
	max_pfn = ((u64)memory_start + (u64)memory_size) >> PAGE_SHIFT;

	pr_info("%s: max_mapnr: %#lx\n", __func__, max_mapnr);
	pr_info("%s: min_low_pfn: %#lx\n", __func__, min_low_pfn);
	pr_info("%s: max_low_pfn: %#lx\n", __func__, max_low_pfn);
	pr_info("%s: max_pfn: %#lx\n", __func__, max_pfn);

	/*
	 * 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).
	 */
	map_size = init_bootmem_node(NODE_DATA(0),
		PFN_UP(TOPHYS((u32)klimit)), min_low_pfn, max_low_pfn);
	memblock_reserve(PFN_UP(TOPHYS((u32)klimit)) << PAGE_SHIFT, map_size);

	/* Add active regions with valid PFNs */
	for_each_memblock(memory, reg) {
		unsigned long start_pfn, end_pfn;

		start_pfn = memblock_region_memory_base_pfn(reg);
		end_pfn = memblock_region_memory_end_pfn(reg);
		memblock_set_node(start_pfn << PAGE_SHIFT,
					(end_pfn - start_pfn) << PAGE_SHIFT, 0);
	}

	/* free bootmem is whole main memory */
	free_bootmem_with_active_regions(0, max_low_pfn);

	/* reserve allocate blocks */
	for_each_memblock(reserved, reg) {
		unsigned long top = reg->base + reg->size - 1;

		pr_debug("reserved - 0x%08x-0x%08x, %lx, %lx\n",
			 (u32) reg->base, (u32) reg->size, top,
						memory_start + lowmem_size - 1);

		if (top <= (memory_start + lowmem_size - 1)) {
			reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
		} else if (reg->base < (memory_start + lowmem_size - 1)) {
			unsigned long trunc_size = memory_start + lowmem_size -
								reg->base;
			reserve_bootmem(reg->base, trunc_size, BOOTMEM_DEFAULT);
		}
	}

	/* XXX need to clip this if using highmem? */
	sparse_memory_present_with_active_regions(0);

#ifdef CONFIG_MMU
	init_bootmem_done = 1;
#endif
	paging_init();
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
	free_reserved_area(start, end, 0, "initrd");
}
#endif

void free_initmem(void)
{
	free_initmem_default(0);
}

void __init mem_init(void)
{
	pg_data_t *pgdat;
	unsigned long reservedpages = 0, codesize, initsize, datasize, bsssize;

	high_memory = (void *)__va(memory_start + lowmem_size - 1);

	/* this will put all memory onto the freelists */
	totalram_pages += free_all_bootmem();

	for_each_online_pgdat(pgdat) {
		unsigned long i;
		struct page *page;

		for (i = 0; i < pgdat->node_spanned_pages; i++) {
			if (!pfn_valid(pgdat->node_start_pfn + i))
				continue;
			page = pgdat_page_nr(pgdat, i);
			if (PageReserved(page))
				reservedpages++;
		}
	}

#ifdef CONFIG_HIGHMEM
	reservedpages -= highmem_setup();
#endif

	codesize = (unsigned long)&_sdata - (unsigned long)&_stext;
	datasize = (unsigned long)&_edata - (unsigned long)&_sdata;
	initsize = (unsigned long)&__init_end - (unsigned long)&__init_begin;
	bsssize = (unsigned long)&__bss_stop - (unsigned long)&__bss_start;

	pr_info("Memory: %luk/%luk available (%luk kernel code, ",
		nr_free_pages() << (PAGE_SHIFT-10),
		num_physpages << (PAGE_SHIFT-10),
		codesize >> 10);
	pr_cont("%luk reserved, %luk data, %luk bss, %luk init)\n",
		reservedpages << (PAGE_SHIFT-10),
		datasize >> 10,
		bsssize >> 10,
		initsize >> 10);

#ifdef CONFIG_MMU
	pr_info("Kernel virtual memory layout:\n");
	pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
	pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
		PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
	pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
		ioremap_bot, ioremap_base);
	pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
		(unsigned long)VMALLOC_START, VMALLOC_END);
#endif
	mem_init_done = 1;
}

#ifndef CONFIG_MMU
int page_is_ram(unsigned long pfn)
{
	return __range_ok(pfn, 0);
}
#else
int page_is_ram(unsigned long pfn)
{
	return pfn < max_low_pfn;
}

/*
 * Check for command-line options that affect what MMU_init will do.
 */
static void mm_cmdline_setup(void)
{
	unsigned long maxmem = 0;
	char *p = cmd_line;

	/* Look for mem= option on command line */
	p = strstr(cmd_line, "mem=");
	if (p) {
		p += 4;
		maxmem = memparse(p, &p);
		if (maxmem && memory_size > maxmem) {
			memory_size = maxmem;
			memblock.memory.regions[0].size = memory_size;
		}
	}
}

/*
 * MMU_init_hw does the chip-specific initialization of the MMU hardware.
 */
static void __init mmu_init_hw(void)
{
	/*
	 * The Zone Protection Register (ZPR) defines how protection will
	 * be applied to every page which is a member of a given zone. At
	 * present, we utilize only two of the zones.
	 * The zone index bits (of ZSEL) in the PTE are used for software
	 * indicators, except the LSB.  For user access, zone 1 is used,
	 * for kernel access, zone 0 is used.  We set all but zone 1
	 * to zero, allowing only kernel access as indicated in the PTE.
	 * For zone 1, we set a 01 binary (a value of 10 will not work)
	 * to allow user access as indicated in the PTE.  This also allows
	 * kernel access as indicated in the PTE.
	 */
	__asm__ __volatile__ ("ori r11, r0, 0x10000000;" \
			"mts rzpr, r11;"
			: : : "r11");
}

/*
 * 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.
 */

/* called from head.S */
asmlinkage void __init mmu_init(void)
{
	unsigned int kstart, ksize;

	if (!memblock.reserved.cnt) {
		pr_emerg("Error memory count\n");
		machine_restart(NULL);
	}

	if ((u32) memblock.memory.regions[0].size < 0x400000) {
		pr_emerg("Memory must be greater than 4MB\n");
		machine_restart(NULL);
	}

	if ((u32) memblock.memory.regions[0].size < kernel_tlb) {
		pr_emerg("Kernel size is greater than memory node\n");
		machine_restart(NULL);
	}

	/* Find main memory where the kernel is */
	memory_start = (u32) memblock.memory.regions[0].base;
	lowmem_size = memory_size = (u32) memblock.memory.regions[0].size;

	if (lowmem_size > CONFIG_LOWMEM_SIZE) {
		lowmem_size = CONFIG_LOWMEM_SIZE;
#ifndef CONFIG_HIGHMEM
		memory_size = lowmem_size;
#endif
	}

	mm_cmdline_setup(); /* FIXME parse args from command line - not used */

	/*
	 * Map out the kernel text/data/bss from the available physical
	 * memory.
	 */
	kstart = __pa(CONFIG_KERNEL_START); /* kernel start */
	/* kernel size */
	ksize = PAGE_ALIGN(((u32)_end - (u32)CONFIG_KERNEL_START));
	memblock_reserve(kstart, ksize);

#if defined(CONFIG_BLK_DEV_INITRD)
	/* Remove the init RAM disk from the available memory. */
	if (initrd_start) {
		unsigned long size;
		size = initrd_end - initrd_start;
		memblock_reserve(virt_to_phys(initrd_start), size);
	}
#endif /* CONFIG_BLK_DEV_INITRD */

	/* Initialize the MMU hardware */
	mmu_init_hw();

	/* Map in all of RAM starting at CONFIG_KERNEL_START */
	mapin_ram();

	/* Extend vmalloc and ioremap area as big as possible */
#ifdef CONFIG_HIGHMEM
	ioremap_base = ioremap_bot = PKMAP_BASE;
#else
	ioremap_base = ioremap_bot = FIXADDR_START;
#endif

	/* Initialize the context management stuff */
	mmu_context_init();

	/* Shortly after that, the entire linear mapping will be available */
	/* This will also cause that unflatten device tree will be allocated
	 * inside 768MB limit */
	memblock_set_current_limit(memory_start + lowmem_size - 1);
}

/* 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 {
		/*
		 * Mem start + kernel_tlb -> here is limit
		 * because of mem mapping from head.S
		 */
		p = __va(memblock_alloc_base(PAGE_SIZE, PAGE_SIZE,
					memory_start + kernel_tlb));
	}
	return p;
}

#endif /* CONFIG_MMU */

void * __init_refok alloc_maybe_bootmem(size_t size, gfp_t mask)
{
	if (mem_init_done)
		return kmalloc(size, mask);
	else
		return alloc_bootmem(size);
}

void * __init_refok zalloc_maybe_bootmem(size_t size, gfp_t mask)
{
	void *p;

	if (mem_init_done)
		p = kzalloc(size, mask);
	else {
		p = alloc_bootmem(size);
		if (p)
			memset(p, 0, size);
	}
	return p;
}