swh:1:snp:49cd9498d6cccc5e78252c27dcb645bcf7bf0c91
Tip revision: 2dcd0af568b0cf583645c8a317dd12e344b1c72a authored by Linus Torvalds on 15 May 2016, 22:43:13 UTC
Linux 4.6
Linux 4.6
Tip revision: 2dcd0af
vmem.c
/*
* Copyright IBM Corp. 2006
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/bootmem.h>
#include <linux/pfn.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/memblock.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
static DEFINE_MUTEX(vmem_mutex);
struct memory_segment {
struct list_head list;
unsigned long start;
unsigned long size;
};
static LIST_HEAD(mem_segs);
static void __ref *vmem_alloc_pages(unsigned int order)
{
if (slab_is_available())
return (void *)__get_free_pages(GFP_KERNEL, order);
return alloc_bootmem_pages((1 << order) * PAGE_SIZE);
}
static inline pud_t *vmem_pud_alloc(void)
{
pud_t *pud = NULL;
pud = vmem_alloc_pages(2);
if (!pud)
return NULL;
clear_table((unsigned long *) pud, _REGION3_ENTRY_EMPTY, PAGE_SIZE * 4);
return pud;
}
static inline pmd_t *vmem_pmd_alloc(void)
{
pmd_t *pmd = NULL;
pmd = vmem_alloc_pages(2);
if (!pmd)
return NULL;
clear_table((unsigned long *) pmd, _SEGMENT_ENTRY_EMPTY, PAGE_SIZE * 4);
return pmd;
}
static pte_t __ref *vmem_pte_alloc(unsigned long address)
{
pte_t *pte;
if (slab_is_available())
pte = (pte_t *) page_table_alloc(&init_mm);
else
pte = alloc_bootmem_align(PTRS_PER_PTE * sizeof(pte_t),
PTRS_PER_PTE * sizeof(pte_t));
if (!pte)
return NULL;
clear_table((unsigned long *) pte, _PAGE_INVALID,
PTRS_PER_PTE * sizeof(pte_t));
return pte;
}
/*
* Add a physical memory range to the 1:1 mapping.
*/
static int vmem_add_mem(unsigned long start, unsigned long size, int ro)
{
unsigned long end = start + size;
unsigned long address = start;
pgd_t *pg_dir;
pud_t *pu_dir;
pmd_t *pm_dir;
pte_t *pt_dir;
int ret = -ENOMEM;
while (address < end) {
pg_dir = pgd_offset_k(address);
if (pgd_none(*pg_dir)) {
pu_dir = vmem_pud_alloc();
if (!pu_dir)
goto out;
pgd_populate(&init_mm, pg_dir, pu_dir);
}
pu_dir = pud_offset(pg_dir, address);
if (MACHINE_HAS_EDAT2 && pud_none(*pu_dir) && address &&
!(address & ~PUD_MASK) && (address + PUD_SIZE <= end) &&
!debug_pagealloc_enabled()) {
pud_val(*pu_dir) = __pa(address) |
_REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE |
(ro ? _REGION_ENTRY_PROTECT : 0);
address += PUD_SIZE;
continue;
}
if (pud_none(*pu_dir)) {
pm_dir = vmem_pmd_alloc();
if (!pm_dir)
goto out;
pud_populate(&init_mm, pu_dir, pm_dir);
}
pm_dir = pmd_offset(pu_dir, address);
if (MACHINE_HAS_EDAT1 && pmd_none(*pm_dir) && address &&
!(address & ~PMD_MASK) && (address + PMD_SIZE <= end) &&
!debug_pagealloc_enabled()) {
pmd_val(*pm_dir) = __pa(address) |
_SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE |
_SEGMENT_ENTRY_YOUNG |
(ro ? _SEGMENT_ENTRY_PROTECT : 0);
address += PMD_SIZE;
continue;
}
if (pmd_none(*pm_dir)) {
pt_dir = vmem_pte_alloc(address);
if (!pt_dir)
goto out;
pmd_populate(&init_mm, pm_dir, pt_dir);
}
pt_dir = pte_offset_kernel(pm_dir, address);
pte_val(*pt_dir) = __pa(address) |
pgprot_val(ro ? PAGE_KERNEL_RO : PAGE_KERNEL);
address += PAGE_SIZE;
}
ret = 0;
out:
return ret;
}
/*
* Remove a physical memory range from the 1:1 mapping.
* Currently only invalidates page table entries.
*/
static void vmem_remove_range(unsigned long start, unsigned long size)
{
unsigned long end = start + size;
unsigned long address = start;
pgd_t *pg_dir;
pud_t *pu_dir;
pmd_t *pm_dir;
pte_t *pt_dir;
pte_t pte;
pte_val(pte) = _PAGE_INVALID;
while (address < end) {
pg_dir = pgd_offset_k(address);
if (pgd_none(*pg_dir)) {
address += PGDIR_SIZE;
continue;
}
pu_dir = pud_offset(pg_dir, address);
if (pud_none(*pu_dir)) {
address += PUD_SIZE;
continue;
}
if (pud_large(*pu_dir)) {
pud_clear(pu_dir);
address += PUD_SIZE;
continue;
}
pm_dir = pmd_offset(pu_dir, address);
if (pmd_none(*pm_dir)) {
address += PMD_SIZE;
continue;
}
if (pmd_large(*pm_dir)) {
pmd_clear(pm_dir);
address += PMD_SIZE;
continue;
}
pt_dir = pte_offset_kernel(pm_dir, address);
*pt_dir = pte;
address += PAGE_SIZE;
}
flush_tlb_kernel_range(start, end);
}
/*
* Add a backed mem_map array to the virtual mem_map array.
*/
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
{
unsigned long address = start;
pgd_t *pg_dir;
pud_t *pu_dir;
pmd_t *pm_dir;
pte_t *pt_dir;
int ret = -ENOMEM;
for (address = start; address < end;) {
pg_dir = pgd_offset_k(address);
if (pgd_none(*pg_dir)) {
pu_dir = vmem_pud_alloc();
if (!pu_dir)
goto out;
pgd_populate(&init_mm, pg_dir, pu_dir);
}
pu_dir = pud_offset(pg_dir, address);
if (pud_none(*pu_dir)) {
pm_dir = vmem_pmd_alloc();
if (!pm_dir)
goto out;
pud_populate(&init_mm, pu_dir, pm_dir);
}
pm_dir = pmd_offset(pu_dir, address);
if (pmd_none(*pm_dir)) {
/* Use 1MB frames for vmemmap if available. We always
* use large frames even if they are only partially
* used.
* Otherwise we would have also page tables since
* vmemmap_populate gets called for each section
* separately. */
if (MACHINE_HAS_EDAT1) {
void *new_page;
new_page = vmemmap_alloc_block(PMD_SIZE, node);
if (!new_page)
goto out;
pmd_val(*pm_dir) = __pa(new_page) |
_SEGMENT_ENTRY | _SEGMENT_ENTRY_LARGE;
address = (address + PMD_SIZE) & PMD_MASK;
continue;
}
pt_dir = vmem_pte_alloc(address);
if (!pt_dir)
goto out;
pmd_populate(&init_mm, pm_dir, pt_dir);
} else if (pmd_large(*pm_dir)) {
address = (address + PMD_SIZE) & PMD_MASK;
continue;
}
pt_dir = pte_offset_kernel(pm_dir, address);
if (pte_none(*pt_dir)) {
void *new_page;
new_page = vmemmap_alloc_block(PAGE_SIZE, node);
if (!new_page)
goto out;
pte_val(*pt_dir) =
__pa(new_page) | pgprot_val(PAGE_KERNEL);
}
address += PAGE_SIZE;
}
ret = 0;
out:
return ret;
}
void vmemmap_free(unsigned long start, unsigned long end)
{
}
/*
* Add memory segment to the segment list if it doesn't overlap with
* an already present segment.
*/
static int insert_memory_segment(struct memory_segment *seg)
{
struct memory_segment *tmp;
if (seg->start + seg->size > VMEM_MAX_PHYS ||
seg->start + seg->size < seg->start)
return -ERANGE;
list_for_each_entry(tmp, &mem_segs, list) {
if (seg->start >= tmp->start + tmp->size)
continue;
if (seg->start + seg->size <= tmp->start)
continue;
return -ENOSPC;
}
list_add(&seg->list, &mem_segs);
return 0;
}
/*
* Remove memory segment from the segment list.
*/
static void remove_memory_segment(struct memory_segment *seg)
{
list_del(&seg->list);
}
static void __remove_shared_memory(struct memory_segment *seg)
{
remove_memory_segment(seg);
vmem_remove_range(seg->start, seg->size);
}
int vmem_remove_mapping(unsigned long start, unsigned long size)
{
struct memory_segment *seg;
int ret;
mutex_lock(&vmem_mutex);
ret = -ENOENT;
list_for_each_entry(seg, &mem_segs, list) {
if (seg->start == start && seg->size == size)
break;
}
if (seg->start != start || seg->size != size)
goto out;
ret = 0;
__remove_shared_memory(seg);
kfree(seg);
out:
mutex_unlock(&vmem_mutex);
return ret;
}
int vmem_add_mapping(unsigned long start, unsigned long size)
{
struct memory_segment *seg;
int ret;
mutex_lock(&vmem_mutex);
ret = -ENOMEM;
seg = kzalloc(sizeof(*seg), GFP_KERNEL);
if (!seg)
goto out;
seg->start = start;
seg->size = size;
ret = insert_memory_segment(seg);
if (ret)
goto out_free;
ret = vmem_add_mem(start, size, 0);
if (ret)
goto out_remove;
goto out;
out_remove:
__remove_shared_memory(seg);
out_free:
kfree(seg);
out:
mutex_unlock(&vmem_mutex);
return ret;
}
/*
* map whole physical memory to virtual memory (identity mapping)
* we reserve enough space in the vmalloc area for vmemmap to hotplug
* additional memory segments.
*/
void __init vmem_map_init(void)
{
unsigned long ro_start, ro_end;
struct memblock_region *reg;
phys_addr_t start, end;
ro_start = PFN_ALIGN((unsigned long)&_stext);
ro_end = (unsigned long)&_eshared & PAGE_MASK;
for_each_memblock(memory, reg) {
start = reg->base;
end = reg->base + reg->size - 1;
if (start >= ro_end || end <= ro_start)
vmem_add_mem(start, end - start, 0);
else if (start >= ro_start && end <= ro_end)
vmem_add_mem(start, end - start, 1);
else if (start >= ro_start) {
vmem_add_mem(start, ro_end - start, 1);
vmem_add_mem(ro_end, end - ro_end, 0);
} else if (end < ro_end) {
vmem_add_mem(start, ro_start - start, 0);
vmem_add_mem(ro_start, end - ro_start, 1);
} else {
vmem_add_mem(start, ro_start - start, 0);
vmem_add_mem(ro_start, ro_end - ro_start, 1);
vmem_add_mem(ro_end, end - ro_end, 0);
}
}
}
/*
* Convert memblock.memory to a memory segment list so there is a single
* list that contains all memory segments.
*/
static int __init vmem_convert_memory_chunk(void)
{
struct memblock_region *reg;
struct memory_segment *seg;
mutex_lock(&vmem_mutex);
for_each_memblock(memory, reg) {
seg = kzalloc(sizeof(*seg), GFP_KERNEL);
if (!seg)
panic("Out of memory...\n");
seg->start = reg->base;
seg->size = reg->size;
insert_memory_segment(seg);
}
mutex_unlock(&vmem_mutex);
return 0;
}
core_initcall(vmem_convert_memory_chunk);