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The maximum size of e820 map array for EFI systems is defined as
E820_X_MAX (E820MAX + 3 * MAX_NUMNODES).
In x86_64 defconfig, this ends up with E820_X_MAX = 320, e820 and e820_saved
are 6404 bytes each.
With larger configs, for example Fedora kernels, E820_X_MAX = 3200, e820
and e820_saved are 64004 bytes each. Most of this space is wasted.
Typical machines have some 20-30 e820 areas at most.
After previous patch, e820 and e820_saved are pointers to e280 maps.
Change them to initially point to maps which are __initdata.
At the very end of kernel init, just before __init[data] sections are freed
in free_initmem(), allocate smaller blocks, copy maps there,
and change pointers.
The late switch makes sure that all functions which can be used to change
e820 maps are no longer accessible (they are all __init functions).
Run-tested.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20160918182125.21000-1-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There was only one use of __initdata_refok and __exit_refok
__init_refok was used 46 times against 82 for __ref.
Those definitions are obsolete since commit 312b1485fb ("Introduce new
section reference annotations tags: __ref, __refdata, __refconst")
This patch removes the following compatibility definitions and replaces
them treewide.
/* compatibility defines */
#define __init_refok __ref
#define __initdata_refok __refdata
#define __exit_refok __ref
I can also provide separate patches if necessary.
(One patch per tree and check in 1 month or 2 to remove old definitions)
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1466796271-3043-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randomizes the virtual address space of kernel memory regions for
x86_64. This first patch adds the infrastructure and does not randomize
any region. The following patches will randomize the physical memory
mapping, vmalloc and vmemmap regions.
This security feature mitigates exploits relying on predictable kernel
addresses. These addresses can be used to disclose the kernel modules
base addresses or corrupt specific structures to elevate privileges
bypassing the current implementation of KASLR. This feature can be
enabled with the CONFIG_RANDOMIZE_MEMORY option.
The order of each memory region is not changed. The feature looks at the
available space for the regions based on different configuration options
and randomizes the base and space between each. The size of the physical
memory mapping is the available physical memory. No performance impact
was detected while testing the feature.
Entropy is generated using the KASLR early boot functions now shared in
the lib directory (originally written by Kees Cook). Randomization is
done on PGD & PUD page table levels to increase possible addresses. The
physical memory mapping code was adapted to support PUD level virtual
addresses. This implementation on the best configuration provides 30,000
possible virtual addresses in average for each memory region. An
additional low memory page is used to ensure each CPU can start with a
PGD aligned virtual address (for realmode).
x86/dump_pagetable was updated to correctly display each region.
Updated documentation on x86_64 memory layout accordingly.
Performance data, after all patches in the series:
Kernbench shows almost no difference (-+ less than 1%):
Before:
Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.63 (1.2695)
User Time 1034.89 (1.18115) System Time 87.056 (0.456416) Percent CPU 1092.9
(13.892) Context Switches 199805 (3455.33) Sleeps 97907.8 (900.636)
After:
Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.489 (1.10636)
User Time 1034.86 (1.36053) System Time 87.764 (0.49345) Percent CPU 1095
(12.7715) Context Switches 199036 (4298.1) Sleeps 97681.6 (1031.11)
Hackbench shows 0% difference on average (hackbench 90 repeated 10 times):
attemp,before,after 1,0.076,0.069 2,0.072,0.069 3,0.066,0.066 4,0.066,0.068
5,0.066,0.067 6,0.066,0.069 7,0.067,0.066 8,0.063,0.067 9,0.067,0.065
10,0.068,0.071 average,0.0677,0.0677
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: Alexander Popov <alpopov@ptsecurity.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: kernel-hardening@lists.openwall.com
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/1466556426-32664-6-git-send-email-keescook@chromium.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Usually, after we have found the proper microcode blob for the current
machine, we stash it away for later use with save_microcode_in_initrd().
However, with builtin microcode which doesn't come from the initrd, we
don't call that function because CONFIG_BLK_DEV_INITRD=n and even if
set, we don't have a valid initrd.
In order to fix this, let's make save_microcode_in_initrd() an
fs_initcall which runs before rootfs_initcall() as this was the time it
was called previously through:
rootfs_initcall(populate_rootfs)
|-> free_initrd()
|-> free_initrd_mem()
|-> save_microcode_in_initrd()
Also, we make it run independently from initrd functionality being
present or not.
And since it is called in the microcode loader only now, we can also
make it static.
Reported-and-tested-by: Jim Bos <jim876@xs4all.nl>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # v4.6
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465225850-7352-3-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull libnvdimm updates from Dan Williams:
"Outside of the new ACPI-NFIT hot-add support this pull request is more
notable for what it does not contain, than what it does. There were a
handful of development topics this cycle, dax get_user_pages, dax
fsync, and raw block dax, that need more more iteration and will wait
for 4.5.
The patches to make devm and the pmem driver NUMA aware have been in
-next for several weeks. The hot-add support has not, but is
contained to the NFIT driver and is passing unit tests. The coredump
support is straightforward and was looked over by Jeff. All of it has
received a 0day build success notification across 107 configs.
Summary:
- Add support for the ACPI 6.0 NFIT hot add mechanism to process
updates of the NFIT at runtime.
- Teach the coredump implementation how to filter out DAX mappings.
- Introduce NUMA hints for allocations made by the pmem driver, and
as a side effect all devm allocations now hint their NUMA node by
default"
* tag 'libnvdimm-for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
coredump: add DAX filtering for FDPIC ELF coredumps
coredump: add DAX filtering for ELF coredumps
acpi: nfit: Add support for hot-add
nfit: in acpi_nfit_init, break on a 0-length table
pmem, memremap: convert to numa aware allocations
devm_memremap_pages: use numa_mem_id
devm: make allocations numa aware by default
devm_memremap: convert to return ERR_PTR
devm_memunmap: use devres_release()
pmem: kill memremap_pmem()
x86, mm: quiet arch_add_memory()
Switch to pr_debug() so that dynamic-debug can disable these messages by
default. This gets noisy in the presence of devm_memremap_pages().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Pull x86 mm changes from Ingo Molnar:
"The main changes in this cycle were:
- reduce the x86/32 PAE per task PGD allocation overhead from 4K to
0.032k (Fenghua Yu)
- early_ioremap/memunmap() usage cleanups (Juergen Gross)
- gbpages support cleanups (Luis R Rodriguez)
- improve AMD Bulldozer (family 0x15) ASLR I$ aliasing workaround to
increase randomization by 3 bits (per bootup) (Hector
Marco-Gisbert)
- misc fixlets"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Improve AMD Bulldozer ASLR workaround
x86/mm/pat: Initialize __cachemode2pte_tbl[] and __pte2cachemode_tbl[] in a bit more readable fashion
init.h: Clean up the __setup()/early_param() macros
x86/mm: Simplify probe_page_size_mask()
x86/mm: Further simplify 1 GB kernel linear mappings handling
x86/mm: Use early_param_on_off() for direct_gbpages
init.h: Add early_param_on_off()
x86/mm: Simplify enabling direct_gbpages
x86/mm: Use IS_ENABLED() for direct_gbpages
x86/mm: Unexport set_memory_ro() and set_memory_rw()
x86/mm, efi: Use early_ioremap() in arch/x86/platform/efi/efi-bgrt.c
x86/mm: Use early_memunmap() instead of early_iounmap()
x86/mm/pat: Ensure different messages in STRICT_DEVMEM and PAT cases
x86/mm: Reduce PAE-mode per task pgd allocation overhead from 4K to 32 bytes
Pull misc x86 fixes from Ingo Molnar:
"This contains:
- EFI fixes
- a boot printout fix
- ASLR/kASLR fixes
- intel microcode driver fixes
- other misc fixes
Most of the linecount comes from an EFI revert"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/ASLR: Avoid PAGE_SIZE redefinition for UML subarch
x86/microcode/intel: Handle truncated microcode images more robustly
x86/microcode/intel: Guard against stack overflow in the loader
x86, mm/ASLR: Fix stack randomization on 64-bit systems
x86/mm/init: Fix incorrect page size in init_memory_mapping() printks
x86/mm/ASLR: Propagate base load address calculation
Documentation/x86: Fix path in zero-page.txt
x86/apic: Fix the devicetree build in certain configs
Revert "efi/libstub: Call get_memory_map() to obtain map and desc sizes"
x86/efi: Avoid triple faults during EFI mixed mode calls
With 32-bit non-PAE kernels, we have 2 page sizes available
(at most): 4k and 4M.
Enabling PAE replaces that 4M size with a 2M one (which 64-bit
systems use too).
But, when booting a 32-bit non-PAE kernel, in one of our
early-boot printouts, we say:
init_memory_mapping: [mem 0x00000000-0x000fffff]
[mem 0x00000000-0x000fffff] page 4k
init_memory_mapping: [mem 0x37000000-0x373fffff]
[mem 0x37000000-0x373fffff] page 2M
init_memory_mapping: [mem 0x00100000-0x36ffffff]
[mem 0x00100000-0x003fffff] page 4k
[mem 0x00400000-0x36ffffff] page 2M
init_memory_mapping: [mem 0x37400000-0x377fdfff]
[mem 0x37400000-0x377fdfff] page 4k
Which is obviously wrong. There is no 2M page available. This
is probably because of a badly-named variable: in the map_range
code: PG_LEVEL_2M.
Instead of renaming all the PG_LEVEL_2M's. This patch just
fixes the printout:
init_memory_mapping: [mem 0x00000000-0x000fffff]
[mem 0x00000000-0x000fffff] page 4k
init_memory_mapping: [mem 0x37000000-0x373fffff]
[mem 0x37000000-0x373fffff] page 4M
init_memory_mapping: [mem 0x00100000-0x36ffffff]
[mem 0x00100000-0x003fffff] page 4k
[mem 0x00400000-0x36ffffff] page 4M
init_memory_mapping: [mem 0x37400000-0x377fdfff]
[mem 0x37400000-0x377fdfff] page 4k
BRK [0x03206000, 0x03206fff] PGTABLE
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20150210212030.665EC267@viggo.jf.intel.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Pull x86 perf updates from Ingo Molnar:
"This series tightens up RDPMC permissions: currently even highly
sandboxed x86 execution environments (such as seccomp) have permission
to execute RDPMC, which may leak various perf events / PMU state such
as timing information and other CPU execution details.
This 'all is allowed' RDPMC mode is still preserved as the
(non-default) /sys/devices/cpu/rdpmc=2 setting. The new default is
that RDPMC access is only allowed if a perf event is mmap-ed (which is
needed to correctly interpret RDPMC counter values in any case).
As a side effect of these changes CR4 handling is cleaned up in the
x86 code and a shadow copy of the CR4 value is added.
The extra CR4 manipulation adds ~ <50ns to the context switch cost
between rdpmc-capable and rdpmc-non-capable mms"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks
perf/x86: Only allow rdpmc if a perf_event is mapped
perf: Pass the event to arch_perf_update_userpage()
perf: Add pmu callbacks to track event mapping and unmapping
x86: Add a comment clarifying LDT context switching
x86: Store a per-cpu shadow copy of CR4
x86: Clean up cr4 manipulation
Pull trivial tree changes from Jiri Kosina:
"Patches from trivial.git that keep the world turning around.
Mostly documentation and comment fixes, and a two corner-case code
fixes from Alan Cox"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
kexec, Kconfig: spell "architecture" properly
mm: fix cleancache debugfs directory path
blackfin: mach-common: ints-priority: remove unused function
doubletalk: probe failure causes OOPS
ARM: cache-l2x0.c: Make it clear that cache-l2x0 handles L310 cache controller
msdos_fs.h: fix 'fields' in comment
scsi: aic7xxx: fix comment
ARM: l2c: fix comment
ibmraid: fix writeable attribute with no store method
dynamic_debug: fix comment
doc: usbmon: fix spelling s/unpriviledged/unprivileged/
x86: init_mem_mapping(): use capital BIOS in comment
Commit 281d4078be ("x86: Make page cache mode a real type")
introduced the symbols __cachemode2pte_tbl and __pte2cachemode_tbl and
exported them via EXPORT_SYMBOL_GPL. The exports are part of a
replacement of code which has been EXPORT_SYMBOL before these changes
resulting in build breakage of out-of-tree non-gpl modules.
Change EXPORT_SYMBOL_GPL to EXPORT-SYMBOL for these two symbols.
Fixes: 281d4078be "x86: Make page cache mode a real type"
Reported-and-tested-by: Steven Noonan <steven@uplinklabs.net>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Link: http://lkml.kernel.org/r/1421926997-28615-1-git-send-email-jgross@suse.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Use capital BIOS in comment. Its cleaner, and allows diference
between BIOS and BIOs.
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The old scheme can lead to failure in certain cases - the
problem is that after bumping step_size the next (non-final)
iteration is only guaranteed to make available a memory block
the size of what step_size was before. E.g. for a memory block
[0,3004600000) we'd have:
iter start end step amount
1 3004400000 30045fffff 2M 2M
2 3004000000 30043fffff 64M 4M
3 3000000000 3003ffffff 2G 64M
4 2000000000 2fffffffff 64G 64G
Yet to map 64G with 4k pages (as happens e.g. under PV Xen) we
need slightly over 128M, but the first three iterations made
only about 70M available.
The condition (new_mapped_ram_size > mapped_ram_size) for
bumping step_size is just not suitable. Instead we want to bump
it when we know we have enough memory available to cover a block
of the new step_size. And rather than making that condition more
complicated than needed, simply adjust step_size by the largest
possible factor we know we can cover at that point - which is
shifting it left by one less than the difference between page
table level shifts. (Interestingly the original STEP_SIZE_SHIFT
definition had a comment hinting at that having been the
intention, just that it should have been PUD_SHIFT-PMD_SHIFT-1
instead of (PUD_SHIFT-PMD_SHIFT)/2, and of course for non-PAE
32-bit we can't really use these two constants as they're equal
there.)
Furthermore the comment in get_new_step_size() didn't get
updated when the bottom-down mapping logic got added. Yet while
an overflow (flushing step_size to zero) of the shift doesn't
matter for the top-down method, it does for bottom-up because
round_up(x, 0) = 0, and an upper range boundary of zero can't
really work well.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/54945C1E020000780005114E@mail.emea.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 fixes from Ingo Molnar:
"Misc fixes (mainly Andy's TLS fixes), plus a cleanup"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/tls: Disallow unusual TLS segments
x86/tls: Validate TLS entries to protect espfix
MAINTAINERS: Add me as x86 VDSO submaintainer
x86/asm: Unify segment selector defines
x86/asm: Guard against building the 32/64-bit versions of the asm-offsets*.c file directly
x86_64, switch_to(): Load TLS descriptors before switching DS and ES
x86/mm: Use min() instead of min_t() in the e820 printout code
x86/mm: Fix zone ranges boot printout
x86/doc: Update documentation after file shuffling
We don't have any good way to figure out what kinds of flushes
are being attempted. Right now, we can try to use the vm
counters, but those only tell us what we actually did with the
hardware (one-by-one vs full) and don't tell us what was actually
_requested_.
This allows us to select out "interesting" TLB flushes that we
might want to optimize (like the ranged ones) and ignore the ones
that we have very little control over (the ones at context
switch).
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: http://lkml.kernel.org/r/20140731154059.4C96CBA5@viggo.jf.intel.com
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The Linux kernel cannot migrate pages used by the kernel. As a result,
kernel pages cannot be hot-removed. So we cannot allocate hotpluggable
memory for the kernel.
In a memory hotplug system, any numa node the kernel resides in should be
unhotpluggable. And for a modern server, each node could have at least
16GB memory. So memory around the kernel image is highly likely
unhotpluggable.
ACPI SRAT (System Resource Affinity Table) contains the memory hotplug
info. But before SRAT is parsed, memblock has already started to allocate
memory for the kernel. So we need to prevent memblock from doing this.
So direct memory mapping page tables setup is the case.
init_mem_mapping() is called before SRAT is parsed. To prevent page
tables being allocated within hotpluggable memory, we will use bottom-up
direction to allocate page tables from the end of kernel image to the
higher memory.
Note:
As for allocating page tables in lower memory, TJ said:
: This is an optional behavior which is triggered by a very specific kernel
: boot param, which I suspect is gonna need to stick around to support
: memory hotplug in the current setup unless we add another layer of address
: translation to support memory hotplug.
As for page tables may occupy too much lower memory if using 4K mapping
(CONFIG_DEBUG_PAGEALLOC and CONFIG_KMEMCHECK both disable using >4k
pages), TJ said:
: But as I said in the same paragraph, parsing SRAT earlier doesn't solve
: the problem in itself either. Ignoring the option if 4k mapping is
: required and memory consumption would be prohibitive should work, no?
: Something like that would be necessary if we're gonna worry about cases
: like this no matter how we implement it, but, frankly, I'm not sure this
: is something worth worrying about.
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Taku Izumi <izumi.taku@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dave Hansen reported that systems between 500G and 600G RAM
crash early if DEBUG_PAGEALLOC is selected.
> [ 0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
> [ 0.000000] [mem 0x00000000-0x000fffff] page 4k
> [ 0.000000] BRK [0x02086000, 0x02086fff] PGTABLE
> [ 0.000000] BRK [0x02087000, 0x02087fff] PGTABLE
> [ 0.000000] BRK [0x02088000, 0x02088fff] PGTABLE
> [ 0.000000] init_memory_mapping: [mem 0xe80ee00000-0xe80effffff]
> [ 0.000000] [mem 0xe80ee00000-0xe80effffff] page 4k
> [ 0.000000] BRK [0x02089000, 0x02089fff] PGTABLE
> [ 0.000000] BRK [0x0208a000, 0x0208afff] PGTABLE
> [ 0.000000] Kernel panic - not syncing: alloc_low_page: ran out of memory
It turns out that we missed increasing needed pages in BRK to
mapping initial 2M and [0,1M) when we switched to use the #PF
handler to set memory mappings:
> commit 8170e6bed4
> Author: H. Peter Anvin <hpa@zytor.com>
> Date: Thu Jan 24 12:19:52 2013 -0800
>
> x86, 64bit: Use a #PF handler to materialize early mappings on demand
Before that, we had the maping from [0,512M) in head_64.S, and we
can spare two pages [0-1M). After that change, we can not reuse
pages anymore.
When we have more than 512M ram, we need an extra page for pgd page
with [512G, 1024g).
Increase pages in BRK for page table to solve the boot crash.
Reported-by: Dave Hansen <dave.hansen@intel.com>
Bisected-by: Dave Hansen <dave.hansen@intel.com>
Tested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@vger.kernel.org> # v3.9 and later
Link: http://lkml.kernel.org/r/1376351004-4015-1-git-send-email-yinghai@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Commit
8d57470d x86, mm: setup page table in top-down
causes a kernel panic while setting mem=2G.
[mem 0x00000000-0x000fffff] page 4k
[mem 0x7fe00000-0x7fffffff] page 1G
[mem 0x7c000000-0x7fdfffff] page 1G
[mem 0x00100000-0x001fffff] page 4k
[mem 0x00200000-0x7bffffff] page 2M
for last entry is not what we want, we should have
[mem 0x00200000-0x3fffffff] page 2M
[mem 0x40000000-0x7bffffff] page 1G
Actually we merge the continuous ranges with same page size too early.
in this case, before merging we have
[mem 0x00200000-0x3fffffff] page 2M
[mem 0x40000000-0x7bffffff] page 2M
after merging them, will get
[mem 0x00200000-0x7bffffff] page 2M
even we can use 1G page to map
[mem 0x40000000-0x7bffffff]
that will cause problem, because we already map
[mem 0x7fe00000-0x7fffffff] page 1G
[mem 0x7c000000-0x7fdfffff] page 1G
with 1G page, aka [0x40000000-0x7fffffff] is mapped with 1G page already.
During phys_pud_init() for [0x40000000-0x7bffffff], it will not
reuse existing that pud page, and allocate new one then try to use
2M page to map it instead, as page_size_mask does not include
PG_LEVEL_1G. At end will have [7c000000-0x7fffffff] not mapped, loop
in phys_pmd_init stop mapping at 0x7bffffff.
That is right behavoir, it maps exact range with exact page size that
we ask, and we should explicitly call it to map [7c000000-0x7fffffff]
before or after mapping 0x40000000-0x7bffffff.
Anyway we need to make sure ranges' page_size_mask correct and consistent
after split_mem_range for each range.
Fix that by calling adjust_range_size_mask before merging range
with same page size.
-v2: update change log.
-v3: add more explanation why [7c000000-0x7fffffff] is not mapped, and
it causes panic.
Bisected-by: "Xie, ChanglongX" <changlongx.xie@intel.com>
Bisected-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Reported-and-tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1370015587-20835-1-git-send-email-yinghai@kernel.org
Cc: <stable@vger.kernel.org> v3.9
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
