// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2006
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/memory_hotplug.h>
#include <linux/memblock.h>
#include <linux/pfn.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
#include <asm/pgalloc.h>
#include <asm/setup.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/set_memory.h>
static DEFINE_MUTEX(vmem_mutex);
static void __ref *vmem_alloc_pages(unsigned int order)
{
unsigned long size = PAGE_SIZE << order;
if (slab_is_available())
return (void *)__get_free_pages(GFP_KERNEL, order);
return memblock_alloc(size, size);
}
static void vmem_free_pages(unsigned long addr, int order)
{
/* We don't expect boot memory to be removed ever. */
if (!slab_is_available() ||
WARN_ON_ONCE(PageReserved(virt_to_page(addr))))
return;
free_pages(addr, order);
}
void *vmem_crst_alloc(unsigned long val)
{
unsigned long *table;
table = vmem_alloc_pages(CRST_ALLOC_ORDER);
if (table)
crst_table_init(table, val);
return table;
}
pte_t __ref *vmem_pte_alloc(void)
{
unsigned long size = PTRS_PER_PTE * sizeof(pte_t);
pte_t *pte;
if (slab_is_available())
pte = (pte_t *) page_table_alloc(&init_mm);
else
pte = (pte_t *) memblock_alloc(size, size);
if (!pte)
return NULL;
memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
return pte;
}
static void vmem_pte_free(unsigned long *table)
{
/* We don't expect boot memory to be removed ever. */
if (!slab_is_available() ||
WARN_ON_ONCE(PageReserved(virt_to_page(table))))
return;
page_table_free(&init_mm, table);
}
#define PAGE_UNUSED 0xFD
/*
* The unused vmemmap range, which was not yet memset(PAGE_UNUSED) ranges
* from unused_sub_pmd_start to next PMD_SIZE boundary.
*/
static unsigned long unused_sub_pmd_start;
static void vmemmap_flush_unused_sub_pmd(void)
{
if (!unused_sub_pmd_start)
return;
memset((void *)unused_sub_pmd_start, PAGE_UNUSED,
ALIGN(unused_sub_pmd_start, PMD_SIZE) - unused_sub_pmd_start);
unused_sub_pmd_start = 0;
}
static void vmemmap_mark_sub_pmd_used(unsigned long start, unsigned long end)
{
/*
* As we expect to add in the same granularity as we remove, it's
* sufficient to mark only some piece used to block the memmap page from
* getting removed (just in case the memmap never gets initialized,
* e.g., because the memory block never gets onlined).
*/
memset((void *)start, 0, sizeof(struct page));
}
static void vmemmap_use_sub_pmd(unsigned long start, unsigned long end)
{
/*
* We only optimize if the new used range directly follows the
* previously unused range (esp., when populating consecutive sections).
*/
if (unused_sub_pmd_start == start) {
unused_sub_pmd_start = end;
if (likely(IS_ALIGNED(unused_sub_pmd_start, PMD_SIZE)))
unused_sub_pmd_start = 0;
return;
}
vmemmap_flush_unused_sub_pmd();
vmemmap_mark_sub_pmd_used(start, end);
}
static void vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end)
{
unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
vmemmap_flush_unused_sub_pmd();
/* Could be our memmap page is filled with PAGE_UNUSED already ... */
vmemmap_mark_sub_pmd_used(start, end);
/* Mark the unused parts of the new memmap page PAGE_UNUSED. */
if (!IS_ALIGNED(start, PMD_SIZE))
memset((void *)page, PAGE_UNUSED, start - page);
/*
* We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of
* consecutive sections. Remember for the last added PMD the last
* unused range in the populated PMD.
*/
if (!IS_ALIGNED(end, PMD_SIZE))
unused_sub_pmd_start = end;
}
/* Returns true if the PMD is completely unused and can be freed. */
static bool vmemmap_unuse_sub_pmd(unsigned long start, unsigned long end)
{
unsigned long page = ALIGN_DOWN(start, PMD_SIZE);
vmemmap_flush_unused_sub_pmd();
memset((void *)start, PAGE_UNUSED, end - start);
return !memchr_inv((void *)page, PAGE_UNUSED, PMD_SIZE);
}
/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
static int __ref modify_pte_table(pmd_t *pmd, unsigned long addr,
unsigned long end, bool add, bool direct)
{
unsigned long prot, pages = 0;
int ret = -ENOMEM;
pte_t *pte;
prot = pgprot_val(PAGE_KERNEL);
if (!MACHINE_HAS_NX)
prot &= ~_PAGE_NOEXEC;
pte = pte_offset_kernel(pmd, addr);
for (; addr < end; addr += PAGE_SIZE, pte++) {
if (!add) {
if (pte_none(*pte))
continue;
if (!direct)
vmem_free_pages((unsigned long) pfn_to_virt(pte_pfn(*pte)), 0);
pte_clear(&init_mm, addr, pte);
} else if (pte_none(*pte)) {
if (!direct) {
void *new_page = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
if (!new_page)
goto out;
pte_val(*pte) = __pa(new_page) | prot;
} else {
pte_val(*pte) = __pa(addr) | prot;
}
} else {
continue;
}
pages++;
}
ret = 0;
out:
if (direct)
update_page_count(PG_DIRECT_MAP_4K, add ? pages : -pages);
return ret;
}
static void try_free_pte_table(pmd_t *pmd, unsigned long start)
{
pte_t *pte;
int i;
/* We can safely assume this is fully in 1:1 mapping & vmemmap area */
pte = pte_offset_kernel(pmd, start);
for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
if (!pte_none(*pte))
return;
}
vmem_pte_free((unsigned long *) pmd_deref(*pmd));
pmd_clear(pmd);
}
/* __ref: we'll only call vmemmap_alloc_block() via vmemmap_populate() */
static int __ref modify_pmd_table(pud_t *pud, unsigned long addr,
unsigned long end, bool add, bool direct)
{
unsigned long next, prot, pages = 0;
int ret = -ENOMEM;
pmd_t *pmd;
pte_t *pte;
prot = pgprot_val(SEGMENT_KERNEL);
if (!MACHINE_HAS_NX)
prot &= ~_SEGMENT_ENTRY_NOEXEC;
pmd = pmd_offset(pud, addr);
for (; addr < end; addr = next, pmd++) {
next = pmd_addr_end(addr, end);
if (!add) {
if (pmd_none(*pmd))
continue;
if (pmd_large(*pmd)) {
if (IS_ALIGNED(addr, PMD_SIZE) &&
IS_ALIGNED(next, PMD_SIZE)) {
if (!direct)
vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
pmd_clear(pmd);
pages++;
} else if (!direct && vmemmap_unuse_sub_pmd(addr, next)) {
vmem_free_pages(pmd_deref(*pmd), get_order(PMD_SIZE));
pmd_clear(pmd);
}
continue;
}
} else if (pmd_none(*pmd)) {
if (IS_ALIGNED(addr, PMD_SIZE) &&
IS_ALIGNED(next, PMD_SIZE) &&
MACHINE_HAS_EDAT1 && addr && direct &&
!debug_pagealloc_enabled()) {
pmd_val(*pmd) = __pa(addr) | prot;
pages++;
continue;
} else if (!direct && MACHINE_HAS_EDAT1) {
void *new_page;
/*
* 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.
*/
new_page = vmemmap_alloc_block(PMD_SIZE, NUMA_NO_NODE);
if (new_page) {
pmd_val(*pmd) = __pa(new_page) | prot;
if (!IS_ALIGNED(addr, PMD_SIZE) ||
!IS_ALIGNED(next, PMD_SIZE)) {
vmemmap_use_new_sub_pmd(addr, next);
}
continue;
}
}
pte = vmem_pte_alloc();
if (!pte)
goto out;
pmd_populate(&init_mm, pmd, pte);
} else if (pmd_large(*pmd)) {
if (!direct)
vmemmap_use_sub_pmd(addr, next);
continue;
}
ret = modify_pte_table(pmd, addr, next, add, direct);
if (ret)
goto out;
if (!add)
try_free_pte_table(pmd, addr & PMD_MASK);
}
ret = 0;
out:
if (direct)
update_page_count(PG_DIRECT_MAP_1M, add ? pages : -pages);
return ret;
}
static void try_free_pmd_table(pud_t *pud, unsigned long start)
{
const unsigned long end = start + PUD_SIZE;
pmd_t *pmd;
int i;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (end > VMALLOC_START)
return;
#ifdef CONFIG_KASAN
if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
return;
#endif
pmd = pmd_offset(pud, start);
for (i = 0; i < PTRS_PER_PMD; i++, pmd++)
if (!pmd_none(*pmd))
return;
vmem_free_pages(pud_deref(*pud), CRST_ALLOC_ORDER);
pud_clear(pud);
}
static int modify_pud_table(p4d_t *p4d, unsigned long addr, unsigned long end,
bool add, bool direct)
{
unsigned long next, prot, pages = 0;
int ret = -ENOMEM;
pud_t *pud;
pmd_t *pmd;
prot = pgprot_val(REGION3_KERNEL);
if (!MACHINE_HAS_NX)
prot &= ~_REGION_ENTRY_NOEXEC;
pud = pud_offset(p4d, addr);
for (; addr < end; addr = next, pud++) {
next = pud_addr_end(addr, end);
if (!add) {
if (pud_none(*pud))
continue;
if (pud_large(*pud)) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE)) {
pud_clear(pud);
pages++;
}
continue;
}
} else if (pud_none(*pud)) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE) &&
MACHINE_HAS_EDAT2 && addr && direct &&
!debug_pagealloc_enabled()) {
pud_val(*pud) = __pa(addr) | prot;
pages++;
continue;
}
pmd = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
if (!pmd)
goto out;
pud_populate(&init_mm, pud, pmd);
} else if (pud_large(*pud)) {
continue;
}
ret = modify_pmd_table(pud, addr, next, add, direct);
if (ret)
goto out;
if (!add)
try_free_pmd_table(pud, addr & PUD_MASK);
}
ret = 0;
out:
if (direct)
update_page_count(PG_DIRECT_MAP_2G, add ? pages : -pages);
return ret;
}
static void try_free_pud_table(p4d_t *p4d, unsigned long start)
{
const unsigned long end = start + P4D_SIZE;
pud_t *pud;
int i;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (end > VMALLOC_START)
return;
#ifdef CONFIG_KASAN
if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
return;
#endif
pud = pud_offset(p4d, start);
for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
if (!pud_none(*pud))
return;
}
vmem_free_pages(p4d_deref(*p4d), CRST_ALLOC_ORDER);
p4d_clear(p4d);
}
static int modify_p4d_table(pgd_t *pgd, unsigned long addr, unsigned long end,
bool add, bool direct)
{
unsigned long next;
int ret = -ENOMEM;
p4d_t *p4d;
pud_t *pud;
p4d = p4d_offset(pgd, addr);
for (; addr < end; addr = next, p4d++) {
next = p4d_addr_end(addr, end);
if (!add) {
if (p4d_none(*p4d))
continue;
} else if (p4d_none(*p4d)) {
pud = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
if (!pud)
goto out;
p4d_populate(&init_mm, p4d, pud);
}
ret = modify_pud_table(p4d, addr, next, add, direct);
if (ret)
goto out;
if (!add)
try_free_pud_table(p4d, addr & P4D_MASK);
}
ret = 0;
out:
return ret;
}
static void try_free_p4d_table(pgd_t *pgd, unsigned long start)
{
const unsigned long end = start + PGDIR_SIZE;
p4d_t *p4d;
int i;
/* Don't mess with any tables not fully in 1:1 mapping & vmemmap area */
if (end > VMALLOC_START)
return;
#ifdef CONFIG_KASAN
if (start < KASAN_SHADOW_END && KASAN_SHADOW_START > end)
return;
#endif
p4d = p4d_offset(pgd, start);
for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
if (!p4d_none(*p4d))
return;
}
vmem_free_pages(pgd_deref(*pgd), CRST_ALLOC_ORDER);
pgd_clear(pgd);
}
static int modify_pagetable(unsigned long start, unsigned long end, bool add,
bool direct)
{
unsigned long addr, next;
int ret = -ENOMEM;
pgd_t *pgd;
p4d_t *p4d;
if (WARN_ON_ONCE(!PAGE_ALIGNED(start | end)))
return -EINVAL;
for (addr = start; addr < end; addr = next) {
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);
if (!add) {
if (pgd_none(*pgd))
continue;
} else if (pgd_none(*pgd)) {
p4d = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
if (!p4d)
goto out;
pgd_populate(&init_mm, pgd, p4d);
}
ret = modify_p4d_table(pgd, addr, next, add, direct);
if (ret)
goto out;
if (!add)
try_free_p4d_table(pgd, addr & PGDIR_MASK);
}
ret = 0;
out:
if (!add)
flush_tlb_kernel_range(start, end);
return ret;
}
static int add_pagetable(unsigned long start, unsigned long end, bool direct)
{
return modify_pagetable(start, end, true, direct);
}
static int remove_pagetable(unsigned long start, unsigned long end, bool direct)
{
return modify_pagetable(start, end, false, direct);
}
/*
* Add a physical memory range to the 1:1 mapping.
*/
static int vmem_add_range(unsigned long start, unsigned long size)
{
return add_pagetable(start, start + size, true);
}
/*
* Remove a physical memory range from the 1:1 mapping.
*/
static void vmem_remove_range(unsigned long start, unsigned long size)
{
remove_pagetable(start, start + size, true);
}
/*
* Add a backed mem_map array to the virtual mem_map array.
*/
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
struct vmem_altmap *altmap)
{
int ret;
mutex_lock(&vmem_mutex);
/* We don't care about the node, just use NUMA_NO_NODE on allocations */
ret = add_pagetable(start, end, false);
if (ret)
remove_pagetable(start, end, false);
mutex_unlock(&vmem_mutex);
return ret;
}
void vmemmap_free(unsigned long start, unsigned long end,
struct vmem_altmap *altmap)
{
mutex_lock(&vmem_mutex);
remove_pagetable(start, end, false);
mutex_unlock(&vmem_mutex);
}
void vmem_remove_mapping(unsigned long start, unsigned long size)
{
mutex_lock(&vmem_mutex);
vmem_remove_range(start, size);
mutex_unlock(&vmem_mutex);
}
struct range arch_get_mappable_range(void)
{
struct range mhp_range;
mhp_range.start = 0;
mhp_range.end = VMEM_MAX_PHYS - 1;
return mhp_range;
}
int vmem_add_mapping(unsigned long start, unsigned long size)
{
struct range range = arch_get_mappable_range();
int ret;
if (start < range.start ||
start + size > range.end + 1 ||
start + size < start)
return -ERANGE;
mutex_lock(&vmem_mutex);
ret = vmem_add_range(start, size);
if (ret)
vmem_remove_range(start, size);
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)
{
phys_addr_t base, end;
u64 i;
for_each_mem_range(i, &base, &end)
vmem_add_range(base, end - base);
__set_memory((unsigned long)_stext,
(unsigned long)(_etext - _stext) >> PAGE_SHIFT,
SET_MEMORY_RO | SET_MEMORY_X);
__set_memory((unsigned long)_etext,
(unsigned long)(__end_rodata - _etext) >> PAGE_SHIFT,
SET_MEMORY_RO);
__set_memory((unsigned long)_sinittext,
(unsigned long)(_einittext - _sinittext) >> PAGE_SHIFT,
SET_MEMORY_RO | SET_MEMORY_X);
__set_memory(__stext_dma, (__etext_dma - __stext_dma) >> PAGE_SHIFT,
SET_MEMORY_RO | SET_MEMORY_X);
/* we need lowcore executable for our LPSWE instructions */
set_memory_x(0, 1);
pr_info("Write protected kernel read-only data: %luk\n",
(unsigned long)(__end_rodata - _stext) >> 10);
}