linux/arch/s390/mm/init.c
Martin Schwidefsky c7e8b2c21c s390: avoid cache aliasing under z/VM and KVM
commit 1f6b83e5e4 ("s390: avoid z13 cache aliasing") checks for the
machine type to optimize address space randomization and zero page
allocation to avoid cache aliases.

This check might fail under a hypervisor with migration support.
z/VMs "Single System Image and Live Guest Relocation" facility will
"fake" the machine type of the oldest system in the group. For example
in a group of zEC12 and Z13 the guest appears to run on a zEC12
(architecture fencing within the relocation domain)

Remove the machine type detection and always use cache aliasing
rules that are known to work for all machines. These are the z13
aliasing rules.

Suggested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2015-11-16 12:04:18 +01:00

207 lines
5.3 KiB
C

/*
* S390 version
* Copyright IBM Corp. 1999
* Author(s): Hartmut Penner (hp@de.ibm.com)
*
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1995 Linus Torvalds
*/
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/memory.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/initrd.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/lowcore.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/ctl_reg.h>
#include <asm/sclp.h>
pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));
unsigned long empty_zero_page, zero_page_mask;
EXPORT_SYMBOL(empty_zero_page);
EXPORT_SYMBOL(zero_page_mask);
static void __init setup_zero_pages(void)
{
unsigned int order;
struct page *page;
int i;
/* Latest machines require a mapping granularity of 512KB */
order = 7;
/* Limit number of empty zero pages for small memory sizes */
while (order > 2 && (totalram_pages >> 10) < (1UL << order))
order--;
empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!empty_zero_page)
panic("Out of memory in setup_zero_pages");
page = virt_to_page((void *) empty_zero_page);
split_page(page, order);
for (i = 1 << order; i > 0; i--) {
mark_page_reserved(page);
page++;
}
zero_page_mask = ((PAGE_SIZE << order) - 1) & PAGE_MASK;
}
/*
* paging_init() sets up the page tables
*/
void __init paging_init(void)
{
unsigned long max_zone_pfns[MAX_NR_ZONES];
unsigned long pgd_type, asce_bits;
init_mm.pgd = swapper_pg_dir;
if (VMALLOC_END > (1UL << 42)) {
asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
pgd_type = _REGION2_ENTRY_EMPTY;
} else {
asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
pgd_type = _REGION3_ENTRY_EMPTY;
}
S390_lowcore.kernel_asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
clear_table((unsigned long *) init_mm.pgd, pgd_type,
sizeof(unsigned long)*2048);
vmem_map_init();
/* enable virtual mapping in kernel mode */
__ctl_load(S390_lowcore.kernel_asce, 1, 1);
__ctl_load(S390_lowcore.kernel_asce, 7, 7);
__ctl_load(S390_lowcore.kernel_asce, 13, 13);
arch_local_irq_restore(4UL << (BITS_PER_LONG - 8));
sparse_memory_present_with_active_regions(MAX_NUMNODES);
sparse_init();
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
free_area_init_nodes(max_zone_pfns);
}
void __init mem_init(void)
{
if (MACHINE_HAS_TLB_LC)
cpumask_set_cpu(0, &init_mm.context.cpu_attach_mask);
cpumask_set_cpu(0, mm_cpumask(&init_mm));
atomic_set(&init_mm.context.attach_count, 1);
set_max_mapnr(max_low_pfn);
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
/* Setup guest page hinting */
cmma_init();
/* this will put all low memory onto the freelists */
free_all_bootmem();
setup_zero_pages(); /* Setup zeroed pages. */
mem_init_print_info(NULL);
printk("Write protected kernel read-only data: %#lx - %#lx\n",
(unsigned long)&_stext,
PFN_ALIGN((unsigned long)&_eshared) - 1);
}
void free_initmem(void)
{
free_initmem_default(POISON_FREE_INITMEM);
}
#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
free_reserved_area((void *)start, (void *)end, POISON_FREE_INITMEM,
"initrd");
}
#endif
#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
{
unsigned long normal_end_pfn = PFN_DOWN(memblock_end_of_DRAM());
unsigned long dma_end_pfn = PFN_DOWN(MAX_DMA_ADDRESS);
unsigned long start_pfn = PFN_DOWN(start);
unsigned long size_pages = PFN_DOWN(size);
unsigned long nr_pages;
int rc, zone_enum;
rc = vmem_add_mapping(start, size);
if (rc)
return rc;
while (size_pages > 0) {
if (start_pfn < dma_end_pfn) {
nr_pages = (start_pfn + size_pages > dma_end_pfn) ?
dma_end_pfn - start_pfn : size_pages;
zone_enum = ZONE_DMA;
} else if (start_pfn < normal_end_pfn) {
nr_pages = (start_pfn + size_pages > normal_end_pfn) ?
normal_end_pfn - start_pfn : size_pages;
zone_enum = ZONE_NORMAL;
} else {
nr_pages = size_pages;
zone_enum = ZONE_MOVABLE;
}
rc = __add_pages(nid, NODE_DATA(nid)->node_zones + zone_enum,
start_pfn, size_pages);
if (rc)
break;
start_pfn += nr_pages;
size_pages -= nr_pages;
}
if (rc)
vmem_remove_mapping(start, size);
return rc;
}
unsigned long memory_block_size_bytes(void)
{
/*
* Make sure the memory block size is always greater
* or equal than the memory increment size.
*/
return max_t(unsigned long, MIN_MEMORY_BLOCK_SIZE, sclp.rzm);
}
#ifdef CONFIG_MEMORY_HOTREMOVE
int arch_remove_memory(u64 start, u64 size)
{
/*
* There is no hardware or firmware interface which could trigger a
* hot memory remove on s390. So there is nothing that needs to be
* implemented.
*/
return -EBUSY;
}
#endif
#endif /* CONFIG_MEMORY_HOTPLUG */