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f05f62d042
linux_dsm_epyc7002/arch/s390/mm/vmem.c
David Hildenbrand f05f62d042 s390/vmem: get rid of memory segment list 
I can't come up with a satisfying reason why we still need the memory
segment list. We used to represent in the list:
- boot memory
- standby memory added via add_memory()
- loaded dcss segments

When loading/unloading dcss segments, we already track them in a
separate list and check for overlaps
(arch/s390/mm/extmem.c:segment_overlaps_others()) when loading segments.

The overlap check was introduced for some segments in
commit b2300b9efe ("[S390] dcssblk: add >2G DCSSs support and stacked
contiguous DCSSs support.")
and was extended to cover all dcss segments in
commit ca57114609 ("s390/extmem: remove code for 31 bit addressing
mode").

Although I doubt that overlaps with boot memory and standby memory
are relevant, let's reshuffle the checks in load_segment() to request
the resource first. This will bail out in case we have overlaps with
other resources (esp. boot memory and standby memory). The order
is now different compared to segment_unload() and segment_unload(), but
that should not matter.

This smells like a leftover from ancient times, let's get rid of it. We
can now convert vmem_remove_mapping() into a void function - everybody
ignored the return value already.

Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20200625150029.45019-1-david@redhat.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [DCSS]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2020-07-01 20:00:49 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2006
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#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 (void *) memblock_phys_alloc(size, size);
}
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_phys_alloc(size, size);
if (!pte)
return NULL;
memset64((u64 *)pte, _PAGE_INVALID, PTRS_PER_PTE);
return pte;
}
/*
* Add a physical memory range to the 1:1 mapping.
*/
static int vmem_add_mem(unsigned long start, unsigned long size)
{
unsigned long pgt_prot, sgt_prot, r3_prot;
unsigned long pages4k, pages1m, pages2g;
unsigned long end = start + size;
unsigned long address = start;
pgd_t *pg_dir;
p4d_t *p4_dir;
pud_t *pu_dir;
pmd_t *pm_dir;
pte_t *pt_dir;
int ret = -ENOMEM;
pgt_prot = pgprot_val(PAGE_KERNEL);
sgt_prot = pgprot_val(SEGMENT_KERNEL);
r3_prot = pgprot_val(REGION3_KERNEL);
if (!MACHINE_HAS_NX) {
pgt_prot &= ~_PAGE_NOEXEC;
sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
r3_prot &= ~_REGION_ENTRY_NOEXEC;
}
pages4k = pages1m = pages2g = 0;
while (address < end) {
pg_dir = pgd_offset_k(address);
if (pgd_none(*pg_dir)) {
p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
if (!p4_dir)
goto out;
pgd_populate(&init_mm, pg_dir, p4_dir);
}
p4_dir = p4d_offset(pg_dir, address);
if (p4d_none(*p4_dir)) {
pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
if (!pu_dir)
goto out;
p4d_populate(&init_mm, p4_dir, pu_dir);
}
pu_dir = pud_offset(p4_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) = address | r3_prot;
address += PUD_SIZE;
pages2g++;
continue;
}
if (pud_none(*pu_dir)) {
pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
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) = address | sgt_prot;
address += PMD_SIZE;
pages1m++;
continue;
}
if (pmd_none(*pm_dir)) {
pt_dir = vmem_pte_alloc();
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) = address | pgt_prot;
address += PAGE_SIZE;
pages4k++;
}
ret = 0;
out:
update_page_count(PG_DIRECT_MAP_4K, pages4k);
update_page_count(PG_DIRECT_MAP_1M, pages1m);
update_page_count(PG_DIRECT_MAP_2G, pages2g);
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 pages4k, pages1m, pages2g;
unsigned long end = start + size;
unsigned long address = start;
pgd_t *pg_dir;
p4d_t *p4_dir;
pud_t *pu_dir;
pmd_t *pm_dir;
pte_t *pt_dir;
pages4k = pages1m = pages2g = 0;
while (address < end) {
pg_dir = pgd_offset_k(address);
if (pgd_none(*pg_dir)) {
address += PGDIR_SIZE;
continue;
}
p4_dir = p4d_offset(pg_dir, address);
if (p4d_none(*p4_dir)) {
address += P4D_SIZE;
continue;
}
pu_dir = pud_offset(p4_dir, address);
if (pud_none(*pu_dir)) {
address += PUD_SIZE;
continue;
}
if (pud_large(*pu_dir)) {
pud_clear(pu_dir);
address += PUD_SIZE;
pages2g++;
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;
pages1m++;
continue;
}
pt_dir = pte_offset_kernel(pm_dir, address);
pte_clear(&init_mm, address, pt_dir);
address += PAGE_SIZE;
pages4k++;
}
flush_tlb_kernel_range(start, end);
update_page_count(PG_DIRECT_MAP_4K, -pages4k);
update_page_count(PG_DIRECT_MAP_1M, -pages1m);
update_page_count(PG_DIRECT_MAP_2G, -pages2g);
}
/*
* 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)
{
unsigned long pgt_prot, sgt_prot;
unsigned long address = start;
pgd_t *pg_dir;
p4d_t *p4_dir;
pud_t *pu_dir;
pmd_t *pm_dir;
pte_t *pt_dir;
int ret = -ENOMEM;
pgt_prot = pgprot_val(PAGE_KERNEL);
sgt_prot = pgprot_val(SEGMENT_KERNEL);
if (!MACHINE_HAS_NX) {
pgt_prot &= ~_PAGE_NOEXEC;
sgt_prot &= ~_SEGMENT_ENTRY_NOEXEC;
}
for (address = start; address < end;) {
pg_dir = pgd_offset_k(address);
if (pgd_none(*pg_dir)) {
p4_dir = vmem_crst_alloc(_REGION2_ENTRY_EMPTY);
if (!p4_dir)
goto out;
pgd_populate(&init_mm, pg_dir, p4_dir);
}
p4_dir = p4d_offset(pg_dir, address);
if (p4d_none(*p4_dir)) {
pu_dir = vmem_crst_alloc(_REGION3_ENTRY_EMPTY);
if (!pu_dir)
goto out;
p4d_populate(&init_mm, p4_dir, pu_dir);
}
pu_dir = pud_offset(p4_dir, address);
if (pud_none(*pu_dir)) {
pm_dir = vmem_crst_alloc(_SEGMENT_ENTRY_EMPTY);
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) | sgt_prot;
address = (address + PMD_SIZE) & PMD_MASK;
continue;
}
pt_dir = vmem_pte_alloc();
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) | pgt_prot;
}
address += PAGE_SIZE;
}
ret = 0;
out:
return ret;
}
void vmemmap_free(unsigned long start, unsigned long end,
struct vmem_altmap *altmap)
{
}
void vmem_remove_mapping(unsigned long start, unsigned long size)
{
mutex_lock(&vmem_mutex);
vmem_remove_range(start, size);
mutex_unlock(&vmem_mutex);
}
int vmem_add_mapping(unsigned long start, unsigned long size)
{
int ret;
if (start + size > VMEM_MAX_PHYS ||
start + size < start)
return -ERANGE;
mutex_lock(&vmem_mutex);
ret = vmem_add_mem(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)
{
struct memblock_region *reg;
for_each_memblock(memory, reg)
vmem_add_mem(reg->base, reg->size);
__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);
}
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