init.c

  1/*
  2 * Copyright (C) 2013 Altera Corporation
  3 * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
  4 * Copyright (C) 2009 Wind River Systems Inc
  5 *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
  6 * Copyright (C) 2004 Microtronix Datacom Ltd
  7 *
  8 * based on arch/m68k/mm/init.c
  9 *
 10 * This file is subject to the terms and conditions of the GNU General Public
 11 * License. See the file "COPYING" in the main directory of this archive
 12 * for more details.
 13 */
 14
 15#include <linux/signal.h>
 16#include <linux/sched.h>
 17#include <linux/kernel.h>
 18#include <linux/errno.h>
 19#include <linux/string.h>
 20#include <linux/types.h>
 21#include <linux/ptrace.h>
 22#include <linux/mman.h>
 23#include <linux/mm.h>
 24#include <linux/init.h>
 25#include <linux/pagemap.h>
 26#include <linux/memblock.h>
 27#include <linux/slab.h>
 28#include <linux/binfmts.h>
 29#include <linux/execmem.h>
 30
 31#include <asm/setup.h>
 32#include <asm/page.h>
 33#include <asm/sections.h>
 34#include <asm/tlb.h>
 35#include <asm/mmu_context.h>
 36#include <asm/cpuinfo.h>
 37#include <asm/processor.h>
 38
 39pgd_t *pgd_current;
 40
 41/*
 42 * paging_init() continues the virtual memory environment setup which
 43 * was begun by the code in arch/head.S.
 44 * The parameters are pointers to where to stick the starting and ending
 45 * addresses of available kernel virtual memory.
 46 */
 47void __init paging_init(void)
 48{
 49	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
 50
 51	pagetable_init();
 52	pgd_current = swapper_pg_dir;
 53
 54	max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
 55
 56	/* pass the memory from the bootmem allocator to the main allocator */
 57	free_area_init(max_zone_pfn);
 58
 59	flush_dcache_range((unsigned long)empty_zero_page,
 60			(unsigned long)empty_zero_page + PAGE_SIZE);
 61}
 62
 63void __init mmu_init(void)
 64{
 65	flush_tlb_all();
 66}
 67
 68pgd_t swapper_pg_dir[PTRS_PER_PGD] __aligned(PAGE_SIZE);
 69pte_t invalid_pte_table[PTRS_PER_PTE] __aligned(PAGE_SIZE);
 70static struct page *kuser_page[1];
 71static struct vm_special_mapping vdso_mapping = {
 72	.name = "[vdso]",
 73	.pages = kuser_page,
 74};
 75
 76static int alloc_kuser_page(void)
 77{
 78	extern char __kuser_helper_start[], __kuser_helper_end[];
 79	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
 80	unsigned long vpage;
 81
 82	vpage = get_zeroed_page(GFP_ATOMIC);
 83	if (!vpage)
 84		return -ENOMEM;
 85
 86	/* Copy kuser helpers */
 87	memcpy((void *)vpage, __kuser_helper_start, kuser_sz);
 88
 89	flush_icache_range(vpage, vpage + KUSER_SIZE);
 90	kuser_page[0] = virt_to_page(vpage);
 91
 92	return 0;
 93}
 94arch_initcall(alloc_kuser_page);
 95
 96int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 97{
 98	struct mm_struct *mm = current->mm;
 99	struct vm_area_struct *vma;
100
101	mmap_write_lock(mm);
102
103	/* Map kuser helpers to user space address */
104	vma = _install_special_mapping(mm, KUSER_BASE, KUSER_SIZE,
105				      VM_READ | VM_EXEC | VM_MAYREAD |
106				      VM_MAYEXEC, &vdso_mapping);
107
108	mmap_write_unlock(mm);
109
110	return IS_ERR(vma) ? PTR_ERR(vma) : 0;
111}
112
113const char *arch_vma_name(struct vm_area_struct *vma)
114{
115	return (vma->vm_start == KUSER_BASE) ? "[kuser]" : NULL;
116}
117
118static const pgprot_t protection_map[16] = {
119	[VM_NONE]					= MKP(0, 0, 0),
120	[VM_READ]					= MKP(0, 0, 1),
121	[VM_WRITE]					= MKP(0, 0, 0),
122	[VM_WRITE | VM_READ]				= MKP(0, 0, 1),
123	[VM_EXEC]					= MKP(1, 0, 0),
124	[VM_EXEC | VM_READ]				= MKP(1, 0, 1),
125	[VM_EXEC | VM_WRITE]				= MKP(1, 0, 0),
126	[VM_EXEC | VM_WRITE | VM_READ]			= MKP(1, 0, 1),
127	[VM_SHARED]					= MKP(0, 0, 0),
128	[VM_SHARED | VM_READ]				= MKP(0, 0, 1),
129	[VM_SHARED | VM_WRITE]				= MKP(0, 1, 0),
130	[VM_SHARED | VM_WRITE | VM_READ]		= MKP(0, 1, 1),
131	[VM_SHARED | VM_EXEC]				= MKP(1, 0, 0),
132	[VM_SHARED | VM_EXEC | VM_READ]			= MKP(1, 0, 1),
133	[VM_SHARED | VM_EXEC | VM_WRITE]		= MKP(1, 1, 0),
134	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= MKP(1, 1, 1)
135};
136DECLARE_VM_GET_PAGE_PROT
137
138#ifdef CONFIG_EXECMEM
139static struct execmem_info execmem_info __ro_after_init;
140
141struct execmem_info __init *execmem_arch_setup(void)
142{
143	execmem_info = (struct execmem_info){
144		.ranges = {
145			[EXECMEM_DEFAULT] = {
146				.start	= MODULES_VADDR,
147				.end	= MODULES_END,
148				.pgprot	= PAGE_KERNEL_EXEC,
149				.alignment = 1,
150			},
151		},
152	};
153
154	return &execmem_info;
155}
156#endif /* CONFIG_EXECMEM */