linux/arch/s390/mm/init.c
Martin Schwidefsky 1b948d6cae s390/mm,tlb: optimize TLB flushing for zEC12
The zEC12 machines introduced the local-clearing control for the IDTE
and IPTE instruction. If the control is set only the TLB of the local
CPU is cleared of entries, either all entries of a single address space
for IDTE, or the entry for a single page-table entry for IPTE.
Without the local-clearing control the TLB flush is broadcasted to all
CPUs in the configuration, which is expensive.

The reset of the bit mask of the CPUs that need flushing after a
non-local IDTE is tricky. As TLB entries for an address space remain
in the TLB even if the address space is detached a new bit field is
required to keep track of attached CPUs vs. CPUs in the need of a
flush. After a non-local flush with IDTE the bit-field of attached CPUs
is copied to the bit-field of CPUs in need of a flush. The ordering
of operations on cpu_attach_mask, attach_count and mm_cpumask(mm) is
such that an underindication in mm_cpumask(mm) is prevented but an
overindication in mm_cpumask(mm) is possible.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-04-03 14:31:00 +02:00

232 lines
5.7 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 <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);
static void __init setup_zero_pages(void)
{
struct cpuid cpu_id;
unsigned int order;
struct page *page;
int i;
get_cpu_id(&cpu_id);
switch (cpu_id.machine) {
case 0x9672: /* g5 */
case 0x2064: /* z900 */
case 0x2066: /* z900 */
case 0x2084: /* z990 */
case 0x2086: /* z990 */
case 0x2094: /* z9-109 */
case 0x2096: /* z9-109 */
order = 0;
break;
case 0x2097: /* z10 */
case 0x2098: /* z10 */
case 0x2817: /* z196 */
case 0x2818: /* z196 */
order = 2;
break;
case 0x2827: /* zEC12 */
case 0x2828: /* zEC12 */
default:
order = 5;
break;
}
/* Limit number of empty zero pages for small memory sizes */
if (order > 2 && totalram_pages <= 16384)
order = 2;
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;
#ifdef CONFIG_64BIT
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;
}
#else
asce_bits = _ASCE_TABLE_LENGTH;
pgd_type = _SEGMENT_ENTRY_EMPTY;
#endif
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);
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)
{
unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
unsigned long start_pfn = PFN_DOWN(start);
unsigned long size_pages = PFN_DOWN(size);
struct zone *zone;
int rc;
rc = vmem_add_mapping(start, size);
if (rc)
return rc;
for_each_zone(zone) {
if (zone_idx(zone) != ZONE_MOVABLE) {
/* Add range within existing zone limits */
zone_start_pfn = zone->zone_start_pfn;
zone_end_pfn = zone->zone_start_pfn +
zone->spanned_pages;
} else {
/* Add remaining range to ZONE_MOVABLE */
zone_start_pfn = start_pfn;
zone_end_pfn = start_pfn + size_pages;
}
if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
continue;
nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
zone_end_pfn - start_pfn : size_pages;
rc = __add_pages(nid, zone, start_pfn, nr_pages);
if (rc)
break;
start_pfn += nr_pages;
size_pages -= nr_pages;
if (!size_pages)
break;
}
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_get_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 */