linux/arch/powerpc/mm/mem.c

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/*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
* and Cort Dougan (PReP) (cort@cs.nmt.edu)
* Copyright (C) 1996 Paul Mackerras
* PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
*
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/gfp.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/suspend.h>
#include <linux/memblock.h>
#include <linux/hugetlb.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/memremap.h>
#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/btext.h>
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/sparsemem.h>
#include <asm/vdso.h>
#include <asm/fixmap.h>
#include <asm/swiotlb.h>
#include <asm/rtas.h>
#include "mmu_decl.h"
#ifndef CPU_FTR_COHERENT_ICACHE
#define CPU_FTR_COHERENT_ICACHE 0 /* XXX for now */
#define CPU_FTR_NOEXECUTE 0
#endif
unsigned long long memory_limit;
#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
EXPORT_SYMBOL(kmap_pte);
pgprot_t kmap_prot;
EXPORT_SYMBOL(kmap_prot);
#define TOP_ZONE ZONE_HIGHMEM
static inline pte_t *virt_to_kpte(unsigned long vaddr)
{
return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
vaddr), vaddr), vaddr);
}
#else
#define TOP_ZONE ZONE_NORMAL
#endif
int page_is_ram(unsigned long pfn)
{
return memblock_is_memory(__pfn_to_phys(pfn));
}
pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
unsigned long size, pgprot_t vma_prot)
{
if (ppc_md.phys_mem_access_prot)
return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);
if (!page_is_ram(pfn))
vma_prot = pgprot_noncached(vma_prot);
return vma_prot;
}
EXPORT_SYMBOL(phys_mem_access_prot);
2005-10-31 02:37:12 +00:00
#ifdef CONFIG_MEMORY_HOTPLUG
#ifdef CONFIG_NUMA
int memory_add_physaddr_to_nid(u64 start)
{
return hot_add_scn_to_nid(start);
}
#endif
int __weak create_section_mapping(unsigned long start, unsigned long end, int nid)
{
return -ENODEV;
}
int __weak remove_section_mapping(unsigned long start, unsigned long end)
{
return -ENODEV;
}
int __meminit arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap,
bool want_memblock)
2005-10-31 02:37:12 +00:00
{
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
int rc;
2005-10-31 02:37:12 +00:00
resize_hpt_for_hotplug(memblock_phys_mem_size());
start = (unsigned long)__va(start);
rc = create_section_mapping(start, start + size, nid);
if (rc) {
pr_warn("Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n",
start, start + size, rc);
return -EFAULT;
}
return __add_pages(nid, start_pfn, nr_pages, altmap, want_memblock);
2005-10-31 02:37:12 +00:00
}
#ifdef CONFIG_MEMORY_HOTREMOVE
int __meminit arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
{
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
struct page *page;
int ret;
/*
* If we have an altmap then we need to skip over any reserved PFNs
* when querying the zone.
*/
page = pfn_to_page(start_pfn);
if (altmap)
page += vmem_altmap_offset(altmap);
ret = __remove_pages(page_zone(page), start_pfn, nr_pages, altmap);
if (ret)
return ret;
/* Remove htab bolted mappings for this section of memory */
start = (unsigned long)__va(start);
ret = remove_section_mapping(start, start + size);
/* Ensure all vmalloc mappings are flushed in case they also
* hit that section of memory
*/
vm_unmap_aliases();
resize_hpt_for_hotplug(memblock_phys_mem_size());
return ret;
}
#endif
#endif /* CONFIG_MEMORY_HOTPLUG */
/*
* walk_memory_resource() needs to make sure there is no holes in a given
* memory range. PPC64 does not maintain the memory layout in /proc/iomem.
* Instead it maintains it in memblock.memory structures. Walk through the
* memory regions, find holes and callback for contiguous regions.
*/
int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *))
{
struct memblock_region *reg;
unsigned long end_pfn = start_pfn + nr_pages;
unsigned long tstart, tend;
int ret = -1;
for_each_memblock(memory, reg) {
tstart = max(start_pfn, memblock_region_memory_base_pfn(reg));
tend = min(end_pfn, memblock_region_memory_end_pfn(reg));
if (tstart >= tend)
continue;
ret = (*func)(tstart, tend - tstart, arg);
if (ret)
break;
}
return ret;
}
EXPORT_SYMBOL_GPL(walk_system_ram_range);
#ifndef CONFIG_NEED_MULTIPLE_NODES
void __init mem_topology_setup(void)
{
max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
min_low_pfn = MEMORY_START >> PAGE_SHIFT;
#ifdef CONFIG_HIGHMEM
max_low_pfn = lowmem_end_addr >> PAGE_SHIFT;
#endif
/* Place all memblock_regions in the same node and merge contiguous
* memblock_regions
*/
memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0);
}
void __init initmem_init(void)
{
/* XXX need to clip this if using highmem? */
sparse_memory_present_with_active_regions(0);
sparse_init();
}
/* mark pages that don't exist as nosave */
static int __init mark_nonram_nosave(void)
{
struct memblock_region *reg, *prev = NULL;
for_each_memblock(memory, reg) {
if (prev &&
memblock_region_memory_end_pfn(prev) < memblock_region_memory_base_pfn(reg))
register_nosave_region(memblock_region_memory_end_pfn(prev),
memblock_region_memory_base_pfn(reg));
prev = reg;
}
return 0;
}
#else /* CONFIG_NEED_MULTIPLE_NODES */
static int __init mark_nonram_nosave(void)
{
return 0;
}
#endif
static bool zone_limits_final;
/*
* The memory zones past TOP_ZONE are managed by generic mm code.
* These should be set to zero since that's what every other
* architecture does.
*/
static unsigned long max_zone_pfns[MAX_NR_ZONES] = {
[0 ... TOP_ZONE ] = ~0UL,
[TOP_ZONE + 1 ... MAX_NR_ZONES - 1] = 0
};
/*
* Restrict the specified zone and all more restrictive zones
* to be below the specified pfn. May not be called after
* paging_init().
*/
void __init limit_zone_pfn(enum zone_type zone, unsigned long pfn_limit)
{
int i;
if (WARN_ON(zone_limits_final))
return;
for (i = zone; i >= 0; i--) {
if (max_zone_pfns[i] > pfn_limit)
max_zone_pfns[i] = pfn_limit;
}
}
/*
* Find the least restrictive zone that is entirely below the
* specified pfn limit. Returns < 0 if no suitable zone is found.
*
* pfn_limit must be u64 because it can exceed 32 bits even on 32-bit
* systems -- the DMA limit can be higher than any possible real pfn.
*/
int dma_pfn_limit_to_zone(u64 pfn_limit)
{
int i;
for (i = TOP_ZONE; i >= 0; i--) {
if (max_zone_pfns[i] <= pfn_limit)
return i;
}
return -EPERM;
}
/*
* paging_init() sets up the page tables - in fact we've already done this.
*/
void __init paging_init(void)
{
unsigned long long total_ram = memblock_phys_mem_size();
phys_addr_t top_of_ram = memblock_end_of_DRAM();
#ifdef CONFIG_PPC32
unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
unsigned long end = __fix_to_virt(FIX_HOLE);
for (; v < end; v += PAGE_SIZE)
map_kernel_page(v, 0, 0); /* XXX gross */
#endif
#ifdef CONFIG_HIGHMEM
map_kernel_page(PKMAP_BASE, 0, 0); /* XXX gross */
pkmap_page_table = virt_to_kpte(PKMAP_BASE);
kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
kmap_prot = PAGE_KERNEL;
#endif /* CONFIG_HIGHMEM */
printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%llx\n",
(unsigned long long)top_of_ram, total_ram);
printk(KERN_DEBUG "Memory hole size: %ldMB\n",
(long int)((top_of_ram - total_ram) >> 20));
#ifdef CONFIG_HIGHMEM
limit_zone_pfn(ZONE_NORMAL, lowmem_end_addr >> PAGE_SHIFT);
#endif
limit_zone_pfn(TOP_ZONE, top_of_ram >> PAGE_SHIFT);
zone_limits_final = true;
free_area_init_nodes(max_zone_pfns);
mark_nonram_nosave();
}
void __init mem_init(void)
{
/*
* book3s is limited to 16 page sizes due to encoding this in
* a 4-bit field for slices.
*/
BUILD_BUG_ON(MMU_PAGE_COUNT > 16);
#ifdef CONFIG_SWIOTLB
swiotlb_init(0);
#endif
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
set_max_mapnr(max_pfn);
mm: concentrate modification of totalram_pages into the mm core Concentrate code to modify totalram_pages into the mm core, so the arch memory initialized code doesn't need to take care of it. With these changes applied, only following functions from mm core modify global variable totalram_pages: free_bootmem_late(), free_all_bootmem(), free_all_bootmem_node(), adjust_managed_page_count(). With this patch applied, it will be much more easier for us to keep totalram_pages and zone->managed_pages in consistence. Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: David Howells <dhowells@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: <sworddragon2@aol.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 22:03:24 +00:00
free_all_bootmem();
#ifdef CONFIG_HIGHMEM
{
unsigned long pfn, highmem_mapnr;
highmem_mapnr = lowmem_end_addr >> PAGE_SHIFT;
for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
phys_addr_t paddr = (phys_addr_t)pfn << PAGE_SHIFT;
struct page *page = pfn_to_page(pfn);
if (!memblock_is_reserved(paddr))
free_highmem_page(page);
}
}
#endif /* CONFIG_HIGHMEM */
#if defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_SMP)
/*
* If smp is enabled, next_tlbcam_idx is initialized in the cpu up
* functions.... do it here for the non-smp case.
*/
per_cpu(next_tlbcam_idx, smp_processor_id()) =
(mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
#endif
mem_init_print_info(NULL);
#ifdef CONFIG_PPC32
pr_info("Kernel virtual memory layout:\n");
pr_info(" * 0x%08lx..0x%08lx : fixmap\n", FIXADDR_START, FIXADDR_TOP);
#ifdef CONFIG_HIGHMEM
pr_info(" * 0x%08lx..0x%08lx : highmem PTEs\n",
PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_NOT_COHERENT_CACHE
pr_info(" * 0x%08lx..0x%08lx : consistent mem\n",
IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE);
#endif /* CONFIG_NOT_COHERENT_CACHE */
pr_info(" * 0x%08lx..0x%08lx : early ioremap\n",
ioremap_bot, IOREMAP_TOP);
pr_info(" * 0x%08lx..0x%08lx : vmalloc & ioremap\n",
VMALLOC_START, VMALLOC_END);
#endif /* CONFIG_PPC32 */
}
void free_initmem(void)
{
ppc_md.progress = ppc_printk_progress;
mark_initmem_nx();
free_initmem_default(POISON_FREE_INITMEM);
}
#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
mm: enhance free_reserved_area() to support poisoning memory with zero Address more review comments from last round of code review. 1) Enhance free_reserved_area() to support poisoning freed memory with pattern '0'. This could be used to get rid of poison_init_mem() on ARM64. 2) A previous patch has disabled memory poison for initmem on s390 by mistake, so restore to the original behavior. 3) Remove redundant PAGE_ALIGN() when calling free_reserved_area(). Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: <sworddragon2@aol.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: David Howells <dhowells@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Jianguo Wu <wujianguo@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michel Lespinasse <walken@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tang Chen <tangchen@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 22:02:51 +00:00
free_reserved_area((void *)start, (void *)end, -1, "initrd");
}
#endif
/*
* This is called when a page has been modified by the kernel.
* It just marks the page as not i-cache clean. We do the i-cache
* flush later when the page is given to a user process, if necessary.
*/
void flush_dcache_page(struct page *page)
{
if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
return;
/* avoid an atomic op if possible */
if (test_bit(PG_arch_1, &page->flags))
clear_bit(PG_arch_1, &page->flags);
}
EXPORT_SYMBOL(flush_dcache_page);
void flush_dcache_icache_page(struct page *page)
{
#ifdef CONFIG_HUGETLB_PAGE
if (PageCompound(page)) {
flush_dcache_icache_hugepage(page);
return;
}
#endif
#if defined(CONFIG_PPC_8xx) || defined(CONFIG_PPC64)
/* On 8xx there is no need to kmap since highmem is not supported */
__flush_dcache_icache(page_address(page));
#else
if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
void *start = kmap_atomic(page);
__flush_dcache_icache(start);
kunmap_atomic(start);
} else {
__flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
}
#endif
}
EXPORT_SYMBOL(flush_dcache_icache_page);
void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
clear_page(page);
/*
* We shouldn't have to do this, but some versions of glibc
* require it (ld.so assumes zero filled pages are icache clean)
* - Anton
*/
flush_dcache_page(pg);
}
EXPORT_SYMBOL(clear_user_page);
void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
struct page *pg)
{
copy_page(vto, vfrom);
/*
* We should be able to use the following optimisation, however
* there are two problems.
* Firstly a bug in some versions of binutils meant PLT sections
* were not marked executable.
* Secondly the first word in the GOT section is blrl, used
* to establish the GOT address. Until recently the GOT was
* not marked executable.
* - Anton
*/
#if 0
if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
return;
#endif
flush_dcache_page(pg);
}
void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
unsigned long addr, int len)
{
unsigned long maddr;
maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
flush_icache_range(maddr, maddr + len);
kunmap(page);
}
EXPORT_SYMBOL(flush_icache_user_range);
/*
* This is called at the end of handling a user page fault, when the
* fault has been handled by updating a PTE in the linux page tables.
* We use it to preload an HPTE into the hash table corresponding to
* the updated linux PTE.
*
* This must always be called with the pte lock held.
*/
void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
pte_t *ptep)
{
#ifdef CONFIG_PPC_STD_MMU
powerpc: Make linux pagetable walk safe with THP enabled We need to have irqs disabled to handle all the possible parallel update for linux page table without holding locks. Events that we are intersted in while walking page tables are 1) Page fault 2) umap 3) THP split 4) THP collapse A) local_irq_disabled: ------------------------ 1) page fault: A none to valid transition via page fault is not an issue because we would either see a none or valid. If it is none, we would error out the page table walk. We may need to use on stack values when checking for type of page table elements, because if we do if (!is_hugepd()) { if (!pmd_none() { if (pmd_bad() { We could take that bad condition because the pmd got converted to a hugepd after the !is_hugepd check via a hugetlb fault. The right way would be to check for pmd_none higher up or use on stack value. 2) A valid to none conversion via unmap: We can safely walk the upper level table, because we don't remove the the page table entries until rcu grace period. So even if we followed a wrong pointer we still have the pointer valid till the grace period. A PTE pointer returned need to be atomically checked for _PAGE_PRESENT and _PAGE_BUSY. A valid pointer returned could becoming none later. To prevent pte_clear we take _PAGE_BUSY. 3) THP split: A valid transparent hugepage is converted to nomal page. Before we split we do pmd_splitting_flush, which sets the hugepage PTE to _PAGE_SPLITTING So when walking page table we need to check for pmd_trans_splitting and handle that. The pte returned should also need to be checked for _PAGE_SPLITTING before setting _PAGE_BUSY similar to _PAGE_PRESENT. We save the value of PTE on stack and check for the flag in the local pte value. If we don't have the value set we can safely operate on the local pte value and we atomicaly set _PAGE_BUSY. 4) THP collapse: A normal page gets converted to hugepage. In the collapse path, we mark the pmd none early (pmdp_clear_flush). With irq disabled, if we are aleady walking page table we would see the pmd_none and won't continue. If we see a valid PMD, we should still check for _PAGE_PRESENT before setting _PAGE_BUSY, to make sure we didn't collapse the PTE to a Huge PTE. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-06-20 09:00:22 +00:00
/*
* We don't need to worry about _PAGE_PRESENT here because we are
* called with either mm->page_table_lock held or ptl lock held
*/
unsigned long access, trap;
if (radix_enabled())
return;
/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
if (!pte_young(*ptep) || address >= TASK_SIZE)
return;
/* We try to figure out if we are coming from an instruction
* access fault and pass that down to __hash_page so we avoid
* double-faulting on execution of fresh text. We have to test
* for regs NULL since init will get here first thing at boot
*
* We also avoid filling the hash if not coming from a fault
*/
trap = current->thread.regs ? TRAP(current->thread.regs) : 0UL;
switch (trap) {
case 0x300:
access = 0UL;
break;
case 0x400:
access = _PAGE_EXEC;
break;
default:
return;
}
hash_preload(vma->vm_mm, address, access, trap);
#endif /* CONFIG_PPC_STD_MMU */
#if (defined(CONFIG_PPC_BOOK3E_64) || defined(CONFIG_PPC_FSL_BOOK3E)) \
&& defined(CONFIG_HUGETLB_PAGE)
if (is_vm_hugetlb_page(vma))
book3e_hugetlb_preload(vma, address, *ptep);
#endif
}
/*
* System memory should not be in /proc/iomem but various tools expect it
* (eg kdump).
*/
static int __init add_system_ram_resources(void)
{
struct memblock_region *reg;
for_each_memblock(memory, reg) {
struct resource *res;
unsigned long base = reg->base;
unsigned long size = reg->size;
res = kzalloc(sizeof(struct resource), GFP_KERNEL);
WARN_ON(!res);
if (res) {
res->name = "System RAM";
res->start = base;
res->end = base + size - 1;
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
WARN_ON(request_resource(&iomem_resource, res) < 0);
}
}
return 0;
}
subsys_initcall(add_system_ram_resources);
#ifdef CONFIG_STRICT_DEVMEM
/*
* devmem_is_allowed(): check to see if /dev/mem access to a certain address
* is valid. The argument is a physical page number.
*
* Access has to be given to non-kernel-ram areas as well, these contain the
* PCI mmio resources as well as potential bios/acpi data regions.
*/
int devmem_is_allowed(unsigned long pfn)
{
if (page_is_rtas_user_buf(pfn))
return 1;
if (iomem_is_exclusive(PFN_PHYS(pfn)))
return 0;
if (!page_is_ram(pfn))
return 1;
return 0;
}
#endif /* CONFIG_STRICT_DEVMEM */