- 根目录:
- arch
- arm
- mm
- init.c
/*
* linux/arch/arm/mm/init.c
*
* Copyright (C) 1995-2005 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/mman.h>
#include <linux/export.h>
#include <linux/nodemask.h>
#include <linux/initrd.h>
#include <linux/of_fdt.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/dma-contiguous.h>
#include <linux/sizes.h>
#include <linux/stop_machine.h>
#include <asm/cp15.h>
#include <asm/mach-types.h>
#include <asm/memblock.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/system_info.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#include "mm.h"
#ifdef CONFIG_CPU_CP15_MMU
unsigned long __init __clear_cr(unsigned long mask)
{
cr_alignment = cr_alignment & ~mask;
return cr_alignment;
}
#endif
static phys_addr_t phys_initrd_start __initdata = 0;
static unsigned long phys_initrd_size __initdata = 0;
static int __init early_initrd(char *p)
{
phys_addr_t start;
unsigned long size;
char *endp;
start = memparse(p, &endp);
if (*endp == ',') {
size = memparse(endp + 1, NULL);
phys_initrd_start = start;
phys_initrd_size = size;
}
return 0;
}
early_param("initrd", early_initrd);
static int __init parse_tag_initrd(const struct tag *tag)
{
pr_warn("ATAG_INITRD is deprecated; "
"please update your bootloader.\n");
phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
phys_initrd_size = tag->u.initrd.size;
return 0;
}
__tagtable(ATAG_INITRD, parse_tag_initrd);
static int __init parse_tag_initrd2(const struct tag *tag)
{
phys_initrd_start = tag->u.initrd.start;
phys_initrd_size = tag->u.initrd.size;
return 0;
}
__tagtable(ATAG_INITRD2, parse_tag_initrd2);
static void __init find_limits(unsigned long *min, unsigned long *max_low,
unsigned long *max_high)
{
*max_low = PFN_DOWN(memblock_get_current_limit());
*min = PFN_UP(memblock_start_of_DRAM());
*max_high = PFN_DOWN(memblock_end_of_DRAM());
}
#ifdef CONFIG_ZONE_DMA
phys_addr_t arm_dma_zone_size __read_mostly;
EXPORT_SYMBOL(arm_dma_zone_size);
/*
* The DMA mask corresponding to the maximum bus address allocatable
* using GFP_DMA. The default here places no restriction on DMA
* allocations. This must be the smallest DMA mask in the system,
* so a successful GFP_DMA allocation will always satisfy this.
*/
phys_addr_t arm_dma_limit;
unsigned long arm_dma_pfn_limit;
static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
unsigned long dma_size)
{
if (size[0] <= dma_size)
return;
size[ZONE_NORMAL] = size[0] - dma_size;
size[ZONE_DMA] = dma_size;
hole[ZONE_NORMAL] = hole[0];
hole[ZONE_DMA] = 0;
}
#endif
void __init setup_dma_zone(const struct machine_desc *mdesc)
{
#ifdef CONFIG_ZONE_DMA
if (mdesc->dma_zone_size) {
arm_dma_zone_size = mdesc->dma_zone_size;
arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
} else
arm_dma_limit = 0xffffffff;
arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
#endif
}
static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
unsigned long max_high)
{
unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
struct memblock_region *reg;
/*
* initialise the zones.
*/
memset(zone_size, 0, sizeof(zone_size));
/*
* The memory size has already been determined. If we need
* to do anything fancy with the allocation of this memory
* to the zones, now is the time to do it.
*/
zone_size[0] = max_low - min;
#ifdef CONFIG_HIGHMEM
zone_size[ZONE_HIGHMEM] = max_high - max_low;
#endif
/*
* Calculate the size of the holes.
* holes = node_size - sum(bank_sizes)
*/
memcpy(zhole_size, zone_size, sizeof(zhole_size));
for_each_memblock(memory, reg) {
unsigned long start = memblock_region_memory_base_pfn(reg);
unsigned long end = memblock_region_memory_end_pfn(reg);
if (start < max_low) {
unsigned long low_end = min(end, max_low);
zhole_size[0] -= low_end - start;
}
#ifdef CONFIG_HIGHMEM
if (end > max_low) {
unsigned long high_start = max(start, max_low);
zhole_size[ZONE_HIGHMEM] -= end - high_start;
}
#endif
}
#ifdef CONFIG_ZONE_DMA
/*
* Adjust the sizes according to any special requirements for
* this machine type.
*/
if (arm_dma_zone_size)
arm_adjust_dma_zone(zone_size, zhole_size,
arm_dma_zone_size >> PAGE_SHIFT);
#endif
free_area_init_node(0, zone_size, min, zhole_size);
}
#ifdef CONFIG_HAVE_ARCH_PFN_VALID
int pfn_valid(unsigned long pfn)
{
return memblock_is_memory(__pfn_to_phys(pfn));
}
EXPORT_SYMBOL(pfn_valid);
#endif
#ifndef CONFIG_SPARSEMEM
static void __init arm_memory_present(void)
{
}
#else
static void __init arm_memory_present(void)
{
struct memblock_region *reg;
for_each_memblock(memory, reg)
memory_present(0, memblock_region_memory_base_pfn(reg),
memblock_region_memory_end_pfn(reg));
}
#endif
static bool arm_memblock_steal_permitted = true;
phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
{
phys_addr_t phys;
BUG_ON(!arm_memblock_steal_permitted);
phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
memblock_free(phys, size);
memblock_remove(phys, size);
return phys;
}
void __init arm_memblock_init(const struct machine_desc *mdesc)
{
/* Register the kernel text, kernel data and initrd with memblock. */
#ifdef CONFIG_XIP_KERNEL
memblock_reserve(__pa(_sdata), _end - _sdata);
#else
memblock_reserve(__pa(_stext), _end - _stext);
#endif
#ifdef CONFIG_BLK_DEV_INITRD
/* FDT scan will populate initrd_start */
if (initrd_start && !phys_initrd_size) {
phys_initrd_start = __virt_to_phys(initrd_start);
phys_initrd_size = initrd_end - initrd_start;
}
initrd_start = initrd_end = 0;
if (phys_initrd_size &&
!memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
(u64)phys_initrd_start, phys_initrd_size);
phys_initrd_start = phys_initrd_size = 0;
}
if (phys_initrd_size &&
memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
(u64)phys_initrd_start, phys_initrd_size);
phys_initrd_start = phys_initrd_size = 0;
}
if (phys_initrd_size) {
memblock_reserve(phys_initrd_start, phys_initrd_size);
/* Now convert initrd to virtual addresses */
initrd_start = __phys_to_virt(phys_initrd_start);
initrd_end = initrd_start + phys_initrd_size;
}
#endif
arm_mm_memblock_reserve();
/* reserve any platform specific memblock areas */
if (mdesc->reserve)
mdesc->reserve();
early_init_fdt_reserve_self();
early_init_fdt_scan_reserved_mem();
/* reserve memory for DMA contiguous allocations */
dma_contiguous_reserve(arm_dma_limit);
arm_memblock_steal_permitted = false;
memblock_dump_all();
}
void __init bootmem_init(void)
{
unsigned long min, max_low, max_high;
memblock_allow_resize();
max_low = max_high = 0;
find_limits(&min, &max_low, &max_high);
early_memtest((phys_addr_t)min << PAGE_SHIFT,
(phys_addr_t)max_low << PAGE_SHIFT);
/*
* Sparsemem tries to allocate bootmem in memory_present(),
* so must be done after the fixed reservations
*/
arm_memory_present();
/*
* sparse_init() needs the bootmem allocator up and running.
*/
sparse_init();
/*
* Now free the memory - free_area_init_node needs
* the sparse mem_map arrays initialized by sparse_init()
* for memmap_init_zone(), otherwise all PFNs are invalid.
*/
zone_sizes_init(min, max_low, max_high);
/*
* This doesn't seem to be used by the Linux memory manager any
* more, but is used by ll_rw_block. If we can get rid of it, we
* also get rid of some of the stuff above as well.
*/
min_low_pfn = min;
max_low_pfn = max_low;
max_pfn = max_high;
}
/*
* Poison init memory with an undefined instruction (ARM) or a branch to an
* undefined instruction (Thumb).
*/
static inline void poison_init_mem(void *s, size_t count)
{
u32 *p = (u32 *)s;
for (; count != 0; count -= 4)
*p++ = 0xe7fddef0;
}
static inline void
free_memmap(unsigned long start_pfn, unsigned long end_pfn)
{
struct page *start_pg, *end_pg;
phys_addr_t pg, pgend;
/*
* Convert start_pfn/end_pfn to a struct page pointer.
*/
start_pg = pfn_to_page(start_pfn - 1) + 1;
end_pg = pfn_to_page(end_pfn - 1) + 1;
/*
* Convert to physical addresses, and
* round start upwards and end downwards.
*/
pg = PAGE_ALIGN(__pa(start_pg));
pgend = __pa(end_pg) & PAGE_MASK;
/*
* If there are free pages between these,
* free the section of the memmap array.
*/
if (pg < pgend)
memblock_free_early(pg, pgend - pg);
}
/*
* The mem_map array can get very big. Free the unused area of the memory map.
*/
static void __init free_unused_memmap(void)
{
unsigned long start, prev_end = 0;
struct memblock_region *reg;
/*
* This relies on each bank being in address order.
* The banks are sorted previously in bootmem_init().
*/
for_each_memblock(memory, reg) {
start = memblock_region_memory_base_pfn(reg);
#ifdef CONFIG_SPARSEMEM
/*
* Take care not to free memmap entries that don't exist
* due to SPARSEMEM sections which aren't present.
*/
start = min(start,
ALIGN(prev_end, PAGES_PER_SECTION));
#else
/*
* Align down here since the VM subsystem insists that the
* memmap entries are valid from the bank start aligned to
* MAX_ORDER_NR_PAGES.
*/
start = round_down(start, MAX_ORDER_NR_PAGES);
#endif
/*
* If we had a previous bank, and there is a space
* between the current bank and the previous, free it.
*/
if (prev_end && prev_end < start)
free_memmap(prev_end, start);
/*
* Align up here since the VM subsystem insists that the
* memmap entries are valid from the bank end aligned to
* MAX_ORDER_NR_PAGES.
*/
prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
MAX_ORDER_NR_PAGES);
}
#ifdef CONFIG_SPARSEMEM
if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
free_memmap(prev_end,
ALIGN(prev_end, PAGES_PER_SECTION));
#endif
}
#ifdef CONFIG_HIGHMEM
static inline void free_area_high(unsigned long pfn, unsigned long end)
{
for (; pfn < end; pfn++)
free_highmem_page(pfn_to_page(pfn));
}
#endif
static void __init free_highpages(void)
{
#ifdef CONFIG_HIGHMEM
unsigned long max_low = max_low_pfn;
struct memblock_region *mem, *res;
/* set highmem page free */
for_each_memblock(memory, mem) {
unsigned long start = memblock_region_memory_base_pfn(mem);
unsigned long end = memblock_region_memory_end_pfn(mem);
/* Ignore complete lowmem entries */
if (end <= max_low)
continue;
/* Truncate partial highmem entries */
if (start < max_low)
start = max_low;
/* Find and exclude any reserved regions */
for_each_memblock(reserved, res) {
unsigned long res_start, res_end;
res_start = memblock_region_reserved_base_pfn(res);
res_end = memblock_region_reserved_end_pfn(res);
if (res_end < start)
continue;
if (res_start < start)
res_start = start;
if (res_start > end)
res_start = end;
if (res_end > end)
res_end = end;
if (res_start != start)
free_area_high(start, res_start);
start = res_end;
if (start == end)
break;
}
/* And now free anything which remains */
if (start < end)
free_area_high(start, end);
}
#endif
}
/*
* mem_init() marks the free areas in the mem_map and tells us how much
* memory is free. This is done after various parts of the system have
* claimed their memory after the kernel image.
*/
void __init mem_init(void)
{
#ifdef CONFIG_HAVE_TCM
/* These pointers are filled in on TCM detection */
extern u32 dtcm_end;
extern u32 itcm_end;
#endif
set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
/* this will put all unused low memory onto the freelists */
free_unused_memmap();
free_all_bootmem();
#ifdef CONFIG_SA1111
/* now that our DMA memory is actually so designated, we can free it */
free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
#endif
free_highpages();
mem_init_print_info(NULL);
#define MLK(b, t) b, t, ((t) - (b)) >> 10
#define MLM(b, t) b, t, ((t) - (b)) >> 20
#define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
pr_notice("Virtual kernel memory layout:\n"
" vector : 0x%08lx - 0x%08lx (%4ld kB)\n"
#ifdef CONFIG_HAVE_TCM
" DTCM : 0x%08lx - 0x%08lx (%4ld kB)\n"
" ITCM : 0x%08lx - 0x%08lx (%4ld kB)\n"
#endif
" fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n"
" vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n"
" lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n"
#ifdef CONFIG_HIGHMEM
" pkmap : 0x%08lx - 0x%08lx (%4ld MB)\n"
#endif
#ifdef CONFIG_MODULES
" modules : 0x%08lx - 0x%08lx (%4ld MB)\n"
#endif
" .text : 0x%p" " - 0x%p" " (%4td kB)\n"
" .init : 0x%p" " - 0x%p" " (%4td kB)\n"
" .data : 0x%p" " - 0x%p" " (%4td kB)\n"
" .bss : 0x%p" " - 0x%p" " (%4td kB)\n",
MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
(PAGE_SIZE)),
#ifdef CONFIG_HAVE_TCM
MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
MLK(ITCM_OFFSET, (unsigned long) itcm_end),
#endif
MLK(FIXADDR_START, FIXADDR_END),
MLM(VMALLOC_START, VMALLOC_END),
MLM(PAGE_OFFSET, (unsigned long)high_memory),
#ifdef CONFIG_HIGHMEM
MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
(PAGE_SIZE)),
#endif
#ifdef CONFIG_MODULES
MLM(MODULES_VADDR, MODULES_END),
#endif
MLK_ROUNDUP(_text, _etext),
MLK_ROUNDUP(__init_begin, __init_end),
MLK_ROUNDUP(_sdata, _edata),
MLK_ROUNDUP(__bss_start, __bss_stop));
#undef MLK
#undef MLM
#undef MLK_ROUNDUP
/*
* Check boundaries twice: Some fundamental inconsistencies can
* be detected at build time already.
*/
#ifdef CONFIG_MMU
BUILD_BUG_ON(TASK_SIZE > MODULES_VADDR);
BUG_ON(TASK_SIZE > MODULES_VADDR);
#endif
#ifdef CONFIG_HIGHMEM
BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
#endif
if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
extern int sysctl_overcommit_memory;
/*
* On a machine this small we won't get
* anywhere without overcommit, so turn
* it on by default.
*/
sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
}
}
#ifdef CONFIG_ARM_KERNMEM_PERMS
struct section_perm {
unsigned long start;
unsigned long end;
pmdval_t mask;
pmdval_t prot;
pmdval_t clear;
};
static struct section_perm nx_perms[] = {
/* Make pages tables, etc before _stext RW (set NX). */
{
.start = PAGE_OFFSET,
.end = (unsigned long)_stext,
.mask = ~PMD_SECT_XN,
.prot = PMD_SECT_XN,
},
/* Make init RW (set NX). */
{
.start = (unsigned long)__init_begin,
.end = (unsigned long)_sdata,
.mask = ~PMD_SECT_XN,
.prot = PMD_SECT_XN,
},
#ifdef CONFIG_DEBUG_RODATA
/* Make rodata NX (set RO in ro_perms below). */
{
.start = (unsigned long)__start_rodata,
.end = (unsigned long)__init_begin,
.mask = ~PMD_SECT_XN,
.prot = PMD_SECT_XN,
},
#endif
};
#ifdef CONFIG_DEBUG_RODATA
static struct section_perm ro_perms[] = {
/* Make kernel code and rodata RX (set RO). */
{
.start = (unsigned long)_stext,
.end = (unsigned long)__init_begin,
#ifdef CONFIG_ARM_LPAE
.mask = ~L_PMD_SECT_RDONLY,
.prot = L_PMD_SECT_RDONLY,
#else
.mask = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
.prot = PMD_SECT_APX | PMD_SECT_AP_WRITE,
.clear = PMD_SECT_AP_WRITE,
#endif
},
};
#endif
/*
* Updates section permissions only for the current mm (sections are
* copied into each mm). During startup, this is the init_mm. Is only
* safe to be called with preemption disabled, as under stop_machine().
*/
static inline void section_update(unsigned long addr, pmdval_t mask,
pmdval_t prot, struct mm_struct *mm)
{
pmd_t *pmd;
pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
#ifdef CONFIG_ARM_LPAE
pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
#else
if (addr & SECTION_SIZE)
pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
else
pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
#endif
flush_pmd_entry(pmd);
local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
}
/* Make sure extended page tables are in use. */
static inline bool arch_has_strict_perms(void)
{
if (cpu_architecture() < CPU_ARCH_ARMv6)
return false;
return !!(get_cr() & CR_XP);
}
void set_section_perms(struct section_perm *perms, int n, bool set,
struct mm_struct *mm)
{
size_t i;
unsigned long addr;
if (!arch_has_strict_perms())
return;
for (i = 0; i < n; i++) {
if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
!IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
pr_err("BUG: section %lx-%lx not aligned to %lx\n",
perms[i].start, perms[i].end,
SECTION_SIZE);
continue;
}
for (addr = perms[i].start;
addr < perms[i].end;
addr += SECTION_SIZE)
section_update(addr, perms[i].mask,
set ? perms[i].prot : perms[i].clear, mm);
}
}
static void update_sections_early(struct section_perm perms[], int n)
{
struct task_struct *t, *s;
read_lock(&tasklist_lock);
for_each_process(t) {
if (t->flags & PF_KTHREAD)
continue;
for_each_thread(t, s)
set_section_perms(perms, n, true, s->mm);
}
read_unlock(&tasklist_lock);
set_section_perms(perms, n, true, current->active_mm);
set_section_perms(perms, n, true, &init_mm);
}
int __fix_kernmem_perms(void *unused)
{
update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
return 0;
}
void fix_kernmem_perms(void)
{
stop_machine(__fix_kernmem_perms, NULL, NULL);
}
#ifdef CONFIG_DEBUG_RODATA
int __mark_rodata_ro(void *unused)
{
update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
return 0;
}
void mark_rodata_ro(void)
{
stop_machine(__mark_rodata_ro, NULL, NULL);
}
void set_kernel_text_rw(void)
{
set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
current->active_mm);
}
void set_kernel_text_ro(void)
{
set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
current->active_mm);
}
#endif /* CONFIG_DEBUG_RODATA */
#else
static inline void fix_kernmem_perms(void) { }
#endif /* CONFIG_ARM_KERNMEM_PERMS */
void free_tcmmem(void)
{
#ifdef CONFIG_HAVE_TCM
extern char __tcm_start, __tcm_end;
poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
#endif
}
void free_initmem(void)
{
fix_kernmem_perms();
free_tcmmem();
poison_init_mem(__init_begin, __init_end - __init_begin);
if (!machine_is_integrator() && !machine_is_cintegrator())
free_initmem_default(-1);
}
#ifdef CONFIG_BLK_DEV_INITRD
static int keep_initrd;
void free_initrd_mem(unsigned long start, unsigned long end)
{
if (!keep_initrd) {
if (start == initrd_start)
start = round_down(start, PAGE_SIZE);
if (end == initrd_end)
end = round_up(end, PAGE_SIZE);
poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
free_reserved_area((void *)start, (void *)end, -1, "initrd");
}
}
static int __init keepinitrd_setup(char *__unused)
{
keep_initrd = 1;
return 1;
}
__setup("keepinitrd", keepinitrd_setup);
#endif