The zone that contains the top of memory will be either ZONE_NORMAL
or ZONE_HIGHMEM depending on the kernel config. There are two functions
that require this information and both of them use an #ifdef to set
a local variable (top_zone). This is a little silly so lets just make it
a constant.
Signed-off-by: NOliver O'Halloran <oohall@gmail.com>
Cc: linux-mm@kvack.org
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

With radix there is no MMU cache. Hence we don't need to do anything in
update_mmu_cache().
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NBalbir Singh <bsingharora@gmail.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

This makes a number of cleanups to handling of mapping failures during
memory hotplug on Power:

For errors creating the linear mapping for the hot-added region:
  * This is now reported with EFAULT which is more appropriate than the
    previous EINVAL (the failure is unlikely to be related to the
    function's parameters)
  * An error in this path now prints a warning message, rather than just
    silently failing to add the extra memory.
  * Previously a failure here could result in the region being partially
    mapped.  We now clean up any partial mapping before failing.

For errors creating the vmemmap for the hot-added region:
   * This is now reported with EFAULT instead of causing a BUG() - this
     could happen for external reason (e.g. full hash table) so it's better
     to handle this non-fatally
   * An error message is also printed, so the failure won't be silent
   * As above a failure could cause a partially mapped region, we now
     clean this up. [mpe: move htab_remove_mapping() out of #ifdef
     CONFIG_MEMORY_HOTPLUG to enable this]
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NPaul Mackerras <paulus@samba.org>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Set IORESOURCE_SYSTEM_RAM in flags of resource ranges with
"System RAM", "Kernel code", "Kernel data", and "Kernel bss".

Note that:

 - IORESOURCE_SYSRAM (i.e. modifier bit) is set in flags when
   IORESOURCE_MEM is already set. IORESOURCE_SYSTEM_RAM is defined
   as (IORESOURCE_MEM|IORESOURCE_SYSRAM).

 - Some archs do not set 'flags' for children nodes, such as
   "Kernel code".  This patch does not change 'flags' in this
   case.
Signed-off-by: NToshi Kani <toshi.kani@hpe.com>
Signed-off-by: NBorislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux-mm <linux-mm@kvack.org>
Cc: linux-parisc@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1453841853-11383-7-git-send-email-bp@alien8.deSigned-off-by: NIngo Molnar <mingo@kernel.org>

With commit 90a545e9 (restrict /dev/mem to idle io memory ranges) mapping
rtas_rmo_buf from user space is failing. Hence we are not able to make
RTAS syscall.

This patch calls page_is_rtas_user_buf before calling iomem_is_exclusive
in  devmem_is_allowed(). This will allow user space to map rtas_rmo_buf
and we are able to make RTAS syscall.
Reported-by: NBharata B Rao <bharata@linux.vnet.ibm.com>
CC: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NVasant Hegde <hegdevasant@linux.vnet.ibm.com>
Acked-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

While pmem is usable as a block device or via DAX mappings to userspace
there are several usage scenarios that can not target pmem due to its
lack of struct page coverage. In preparation for "hot plugging" pmem
into the vmemmap add ZONE_DEVICE as a new zone to tag these pages
separately from the ones that are subject to standard page allocations.
Importantly "device memory" can be removed at will by userspace
unbinding the driver of the device.

Having a separate zone prevents allocation and otherwise marks these
pages that are distinct from typical uniform memory.  Device memory has
different lifetime and performance characteristics than RAM.  However,
since we have run out of ZONES_SHIFT bits this functionality currently
depends on sacrificing ZONE_DMA.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Jerome Glisse <j.glisse@gmail.com>
[hch: various simplifications in the arch interface]
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

__flush_dcache_icache_phys() requires the ability to access the
memory with the MMU disabled, which means that on a 32-bit system
any memory above 4 GiB is inaccessible.  In particular, mpc86xx is
32-bit and can have more than 4 GiB of RAM.
Signed-off-by: NScott Wood <scottwood@freescale.com>

This function can run on systems where physical addresses don't
fit in unsigned long, so make sure to use the macro that contains the
proper cast.
Signed-off-by: NScott Wood <scottwood@freescale.com>

We have a powerpc specific global called mem_init_done which is "set on
boot once kmalloc can be called".

But that's not *quite* true. We set it at the bottom of mem_init(), and
rely on the fact that mm_init() calls kmem_cache_init() immediately
after that, and nothing is running in parallel.

So replace it with the generic and 100% correct slab_is_available().
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We did part of sparse initialisation in setup_arch and part in
initmem_init. Put them together.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Tested-by: NEmil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

At the moment we transition from the memblock alloctor to the bootmem
allocator. Gitting rid of the bootmem allocator removes a bunch of
complicated code (most of which I owe the dubious honour of being
responsible for writing).
Signed-off-by: NAnton Blanchard <anton@samba.org>
Tested-by: NEmil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

We have an extra level of indirection on memory hot remove which is not
matched on memory hot add. Memory hotplug is book3s only, so there is
no need for it.

This also enables means remove_memory() (ie memory hot unplug) works
on powernv.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Commit 1c98025c "powerpc: Dynamic DMA
zone limits" updated how zones are created in paging_init(), but missed
the NUMA version of paging_init().  This was noticed via a linker
error, since dma_pfn_limit_to_zone() was, like the non-NUMA
paging_init(), limited by #ifndef CONFIG_NEED_MULTIPLE_NODES.

It turns out that the NUMA paging_init() was not actually doing
anything different from the standard paging_init(), other than a couple
debug prints, a couple 32-bit-only ifdef sections, and a call to
mark_nonram_nosave().  It's not clear whether mark_nonram_nosave() is
inherently wrong to do for NUMA, or just not useful on targets that
have NUMA, but for now I'm preserving the existing behavior.

Fixes: 1c98025c "powerpc: Dynamic DMA zone limits"
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NScott Wood <scottwood@freescale.com>

Platform code can call limit_zone_pfn() to set appropriate limits
for ZONE_DMA and ZONE_DMA32, and dma_direct_alloc_coherent() will
select a suitable zone based on a device's mask and the pfn limits that
platform code has configured.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Cc: Shaohui Xie <Shaohui.Xie@freescale.com>

This patch introduces zone_for_memory() to arch_add_memory() on powerpc
to ensure new, higher memory added into ZONE_MOVABLE if movable zone has
already setup.
Signed-off-by: NWang Nan <wangnan0@huawei.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: "Mel Gorman" <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The memory remove code for powerpc/pseries should call remove_memory()
so that we are holding the hotplug_memory lock during memory remove
operations.

This patch updates the memory node remove handler to call remove_memory()
and adds a ppc_md.remove_memory() entry to handle pseries specific work
that is called from arch_remove_memory().

During memory remove in pseries_remove_memblock() we have to stay with
removing memory one section at a time. This is needed because of how memory
resources are handled. During memory add for pseries (via the probe file in
sysfs) we add memory one section at a time which gives us a memory resource
for each section. Future patches will aim to address this so will not have
to remove memory one section at a time.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

[sfr@canb.auug.org.au: fix powerpc build]
Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Rafael J . Wysocki" <rjw@sisk.pl>
Cc: Chen Tang <imtangchen@gmail.com>
Cc: Gong Chen <gong.chen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Liu Jiang <jiang.liu@huawei.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

add_system_ram_resources() is a subsys_initcall.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

There are a few things that make the existing hw tablewalk handlers
unsuitable for e6500:

 - Indirect entries go in TLB1 (though the resulting direct entries go in
   TLB0).

 - It has threads, but no "tlbsrx." -- so we need a spinlock and
   a normal "tlbsx".  Because we need this lock, hardware tablewalk
   is mandatory on e6500 unless we want to add spinlock+tlbsx to
   the normal bolted TLB miss handler.

 - TLB1 has no HES (nor next-victim hint) so we need software round robin
   (TODO: integrate this round robin data with hugetlb/KVM)

 - The existing tablewalk handlers map half of a page table at a time,
   because IBM hardware has a fixed 1MiB indirect page size.  e6500
   has variable size indirect entries, with a minimum of 2MiB.
   So we can't do the half-page indirect mapping, and even if we
   could it would be less efficient than mapping the full page.

 - Like on e5500, the linear mapping is bolted, so we don't need the
   overhead of supporting nested tlb misses.

Note that hardware tablewalk does not work in rev1 of e6500.
We do not expect to support e6500 rev1 in mainline Linux.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>

Previous commit 46723bfa... introduced a new config option
HAVE_BOOTMEM_INFO_NODE that ended up breaking memory hot-remove for ppc
when sparse vmemmap is not defined.

This patch defines HAVE_BOOTMEM_INFO_NODE for ppc and adds the call to
register_page_bootmem_info_node. Without this we get a BUG_ON for memory
hot remove in put_page_bootmem().

This also adds a stub for register_page_bootmem_memmap to allow ppc to build
with sparse vmemmap defined. Leaving this as a stub is fine since the same
vmemmap addresses are also handled in vmemmap_populate and as such are
properly mapped.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
CC: <stable@vger.kernel.org> [v3.9+]

Memory I/O resources need to be marked as busy or else we cannot remove
them when doing memory hot remove.
Signed-off-by: NNathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Prepare for killing free_all_bootmem_node() by using free_all_bootmem().
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Prepare for removing num_physpages and simplify mem_init().
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NJiang Liu <jiang.liu@huawei.com>
Acked-by: NDavid 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NJiang 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change signature of free_reserved_area() according to Russell King's
suggestion to fix following build warnings:

  arch/arm/mm/init.c: In function 'mem_init':
  arch/arm/mm/init.c:603:2: warning: passing argument 1 of 'free_reserved_area' makes integer from pointer without a cast [enabled by default]
    free_reserved_area(__va(PHYS_PFN_OFFSET), swapper_pg_dir, 0, NULL);
    ^
  In file included from include/linux/mman.h:4:0,
                   from arch/arm/mm/init.c:15:
  include/linux/mm.h:1301:22: note: expected 'long unsigned int' but argument is of type 'void *'
   extern unsigned long free_reserved_area(unsigned long start, unsigned long end,

   mm/page_alloc.c: In function 'free_reserved_area':
>> mm/page_alloc.c:5134:3: warning: passing argument 1 of 'virt_to_phys' makes pointer from integer without a cast [enabled by default]
   In file included from arch/mips/include/asm/page.h:49:0,
                    from include/linux/mmzone.h:20,
                    from include/linux/gfp.h:4,
                    from include/linux/mm.h:8,
                    from mm/page_alloc.c:18:
   arch/mips/include/asm/io.h:119:29: note: expected 'const volatile void *' but argument is of type 'long unsigned int'
   mm/page_alloc.c: In function 'free_area_init_nodes':
   mm/page_alloc.c:5030:34: warning: array subscript is below array bounds [-Warray-bounds]

Also address some minor code review comments.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Reported-by: NArnd Bergmann <arnd@arndb.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: <sworddragon2@aol.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Use helper function free_highmem_page() to free highmem pages into
the buddy system.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: "Suzuki K. Poulose" <suzuki@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use common help functions to free reserved pages.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anatolij Gustschin <agust@denx.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This fixes the following checkpatch.pl warnings:

WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
+EXPORT_SYMBOL(kmap_prot);

WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
+EXPORT_SYMBOL(kmap_pte);
Signed-off-by: NValentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>

For removing memory, we need to remove page tables.  But it depends on
architecture.  So the patch introduce arch_remove_memory() for removing
page table.  Now it only calls __remove_pages().

Note: __remove_pages() for some archtecuture is not implemented
      (I don't know how to implement it for s390).
Signed-off-by: NWen Congyang <wency@cn.fujitsu.com>
Signed-off-by: NTang Chen <tangchen@cn.fujitsu.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The only persistent change made by this loop is calling
memblock_set_node() once for each memblock, which is not useful (and has
no effect) as memblock_set_node() is not called with any
memblock-specific parameters.

Subsistute a single memblock_set_node().
Signed-off-by: NCody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Remove the dependency on PCI initialization for SWIOTLB initialization.
So that PCI can be initialized at proper time.

SWIOTLB is partly determined by PCI inbound/outbound map which is assigned
in PCI initialization. But swiotlb_init() should be done at the stage of
mem_init() which is much earlier than PCI initialization. So we reserve the
memory for SWIOTLB first and free it if not necessary.

All boards are converted to fit this change.
Signed-off-by: NJia Hongtao <B38951@freescale.com>
Signed-off-by: NLi Yang <leoli@freescale.com>
Acked-by: NTony Breeds <tony@bakeyournoodle.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

There are some device-tree nodes, whose values are of type phys_addr_t.
The phys_addr_t is variable sized based on the CONFIG_PHSY_T_64BIT.

Change these to a fixed unsigned long long for consistency.

This patch does the change only for memory_limit.

The following is a list of such variables which need the change:

 1) kernel_end, crashk_size - in arch/powerpc/kernel/machine_kexec.c

 2) (struct resource *)crashk_res.start - We could export a local static
    variable from machine_kexec.c.

Changing the above values might break the kexec-tools. So, I will
fix kexec-tools first to handle the different sized values and then change
 the above.
Suggested-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NSuzuki K. Poulose <suzuki@in.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

When we map a page that wasn't icache cleared before, do so when first
mapping it in KVM using the same information bits as the Linux mapping
logic. That way we are 100% sure that any page we map does not have stale
entries in the icache.
Signed-off-by: NAlexander Graf <agraf@suse.de>

Signed-off-by: NCong Wang <amwang@redhat.com>

powerpc doesn't access early_node_map[] directly and enabling
HAVE_MEMBLOCK_NODE_MAP is trivial - replacing add_active_range() calls
with memblock_set_node() and selecting HAVE_MEMBLOCK_NODE_MAP is
enough.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Yinghai Lu <yinghai@kernel.org>

With CONFIG_STRICT_DEVMEM=y, user space cannot read any part of /dev/mem.
Since this breaks librtas, punch a hole in /dev/mem to allow access to the
rmo_buffer that librtas needs.

Anton Blanchard reported the problem and helped with the fix.

A quick test for this patch:

       # cat /proc/rtas/rmo_buffer
       000000000f190000 10000

       # python -c "print 0x000000000f190000 / 0x10000"
       3865

       # dd if=/dev/mem of=/tmp/foo count=1 bs=64k skip=3865
       1+0 records in
       1+0 records out
       65536 bytes (66 kB) copied, 0.000205235 s, 319 MB/s

       # dd if=/dev/mem of=/tmp/foo
       dd: reading `/dev/mem': Operation not permitted
       0+0 records in
       0+0 records out
       0 bytes (0 B) copied, 0.00022519 s, 0.0 kB/s
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

This avoids an extra find_vma() and is less error-prone.
Signed-off-by: NBecky Bruce <beckyb@kernel.crashing.org>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

As described in the help text in the patch, this token restricts general
access to /dev/mem as a way of increasing the security. Specifically, access
to exclusive IOMEM and kernel RAM is denied unless CONFIG_STRICT_DEVMEM is
set to 'n'.

Implement the 'devmem_is_allowed()' interface for Powerpc. It will be
called from range_is_allowed() when userpsace attempts to access /dev/mem.

This patch is based on an earlier patch from Steve Best and with input from
Paul Mackerras and Scott Wood.

[BenH] Fixed a typo or two and removed the generic change which should
       be submitted as a separate patch
Signed-off-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>