Page table entries are made invalid by writing a zero into the the PTE
slot in a page table.  This creates a race condition with the TLB
modify handlers when they are updating the PTE.

CPU0                              CPU1

Test for _PAGE_PRESENT
.                                 set to not _PAGE_PRESENT (zero)
Set to _PAGE_VALID

So now the page not present value (zero) is suddenly valid and user
space programs have access to physical page zero.

We close the race by putting the test for _PAGE_PRESENT and setting of
_PAGE_VALID into an atomic LL/SC section.  This requires more registers
than just K0 and K1 in the handlers, so we need to save some registers
to a save area and then restore them when we are done.

The save area is an array of cacheline aligned structures that should
not suffer cache line bouncing as they are CPU private.

[ralf@linux-mips.org: Fix !defined(CONFIG_MIPS_PGD_C0_CONTEXT) build error.]
Signed-off-by: NDavid Daney <david.daney@cavium.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2577/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This can be used from either 32-bit or 64-bit code to generate logical
right shifts of any constant amount.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2576/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

From: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>

platform data for simple backlight driver for LM3530
in the u5500 platform
Signed-off-by: NShreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is not necessary to share the same notifier.h.

This patch already moves register_reboot_notifier() and
unregister_reboot_notifier() from kernel/notifier.c to kernel/sys.c.

[amwang@redhat.com: make allyesconfig succeed on ppc64]
Signed-off-by: NWANG Cong <amwang@redhat.com>
Cc: David Miller <davem@davemloft.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: NWANG Cong <amwang@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

GCC 4.6's -Wunused-but-set-variable found some dead code.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Linux can have pids up to 4*1024*1024.  To handle such huge numbers
pid_buf needs to be larger.
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Until now UML had no x86_64 vDSO.  So glibc always used the vsyscall page
for gettimeday() and friends.  Calls to gettimeday() returned falsely the
host time and confused some programs.

This patch adds a vDSO which turns all __vdso_* calls into a system call
so that UML can trap them.

As glibc still uses the vsyscall page for static binaries this patch
improves the situation only for dynamic binaries.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Implement arch_vma_name() and make get_gate_vma(), in_gate_area() and
in_gate_area_no_mm() a nop.

We need arch_vma_name() to support vDSO.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When UML is unable to reuse the host's vDSO FIXADDR_USER_START is zero.
To handle this special case correclty we have to implement custom gate
area helper methods.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Reusing the host's vDSO makes only sense on x86_32.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When creating the temp file there's a memory and file descriptor leak upon
error.
Signed-off-by: NDavidlohr Bueso <dave@gnu.org>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Do not free memory when you failed to allocate it.
Signed-off-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix this warning:

  arch/um/os-Linux/helper.c: In function `helper_child':
  arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of `write', declared with attribute warn_unused_result

[richard@nod.at: happens only with -D_FORTIFY_SOURCE=2]
Signed-off-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix this warning:

  arch/um/drivers/cow_user.c: In function `absolutize':
  arch/um/drivers/cow_user.c:189:7: warning: ignoring return value of `chdir', declared with attribute warn_unused_result

[richard@nod.at: happens only with -D_FORTIFY_SOURCE=2]
Signed-off-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Perform memory cleanup on exit.  On receiving invalid 'pid' we still
should clean 'output' variable.
Signed-off-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 0954828f ("kconfig: replace KERNELVERSION usage by the
mainmenu's prompt") made the kernel version disappear from the generated
.config file when configuring for UML.  As UML's Kconfig doesn't have a
mainmenu, kconfig falls back to the default string "Linux Kernel
Configuration".

Add a suitable mainmenu to the main UML Kconfig file to fix this.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To make netconsole usable on UML, its ethernet driver needs netpoll
support.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When UML is compiled with _FORTIFY_SOURCE we have to export all _chk()
functions which are used in modules.  For now it's only the case for
__sprintf_chk().
Tested-by: NFlorian Fainelli <florian@openwrt.org>
Reported-by: NFlorian Fainelli <florian@openwrt.org>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Acked-by: NVitaliy Ivanov <vitalivanov@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Both sys-i386 and sys-x86_64 support now ndelay().  The delay functions
are based on arch/x86/lib/delay.c.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The address limit is already set in flush_old_exec() so this
set_fs(USER_DS) is redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no need to define VM_{STACK,DATA}_DEFAULT_FLAGS as variable.
It's also useless to test for TIF_IA32 as 64bit UML has no IA32 emulation.
Signed-off-by: NRichard Weinberger <richard@nod.at>
Acked-by: NRandy Dunlap <rdunlap@xenotime.net>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The address limit is already set in flush_old_exec() so those calls to
set_fs(USER_DS) are redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix some harmless warnings such as

  arch/cris/arch-v32/mach-a3/pinmux.c:273: warning: ISO C90 forbids mixed declarations and code:
Signed-off-by: NWANG Cong <xiyou.wangcong@gmail.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The address limit is already set in flush_old_exec() so those calls to
set_fs(USER_DS) are redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The address limit is already set in flush_old_exec() so this
set_fs(USER_DS) is redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The address limit is already set in flush_old_exec() so this
set_fs(USER_DS) is redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The address limit is already set in flush_old_exec() so those calls to
set_fs(USER_DS) are redundant.
Signed-off-by: NMathias Krause <minipli@googlemail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Luckily there are still a few software PTE bits remaining and they even
match up in both the sun4u and sun4v pte layouts.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make use of the generic RCU page table freeing on Sparc64, doing so allows
for race-free software page-table walkers like gup_fast().
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With the recent mmu_gather changes that included generic RCU freeing of
page-tables, it is now quite straightforward to implement gup_fast() on
sparc64.

This patch:

Remove the page table quicklists.  They are pointless and make it harder
to use RCU page table freeing and share code with other architectures.

BTW, this is the second time this has happened, see commit 3c936465
("[SPARC64]: Kill pgtable quicklists and use SLAB.")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the following build error:

  arch/xtensa/include/asm/uaccess.h:403: error: implicit declaration of function 'prefetch'
  arch/xtensa/include/asm/uaccess.h:412: error: implicit declaration of function 'prefetchw'
Signed-off-by: NWANG Cong <xiyou.wangcong@gmail.com>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Prevent an arbitrary kernel read.  Check the user pointer with access_ok()
before copying data in.

[akpm@linux-foundation.org: s/EIO/EFAULT/]
Signed-off-by: NDan Rosenberg <drosenberg@vsecurity.com>
Cc: Christian Zankel <chris@zankel.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove custom implementation of hex_to_bin().
Signed-off-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
To: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1580/Acked-by: NFlorian Fainelli <florian@openwrt.org>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Enable cpu_has_clo_clz only when CONFIG_CPU_MIPS32 or CONFIG_CPU_MIPS64
is selected.  This will optimize fls() and __fls() to use CLZ insn, and
eventually ffs() and __ffs() as well.

Malta and MIPSSim are development platforms, and need to take care of
various processor configurations, release rivisions and so on, even
across different MIPS ISAs.  For such platforms we have to be careful,
for instance, with turning on cpu_has_mips{32,64}r[12] features.

As for CLZ, all MIPS32/64 processors support it, regardless of release
revisions.
Signed-off-by: NShinya Kuribayashi <skuribay@pobox.com>
To: David VomLehn <dvomlehn@cisco.com>
To: macro@linux-mips.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1453/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

This will optimize fls() and __fls() to use CLZ throughout the kernel,
and any other optimizations that depend on constant cpu_has_* values
will also be used.
Signed-off-by: NDavid VomLehn <dvomlehn@cisco.com>
Signed-off-by: NShinya Kuribayashi <skuribay@pobox.com>
To: David VomLehn <dvomlehn@cisco.com>
To: macro@linux-mips.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1452/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Signed-off-by: NRalf Baechle <ralf@linux-mips.org>
To: Sergei Shtylyov <sshtylyov@mvista.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2391/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

fixrange_init() allocates page tables for all addresses higher than
FIXADDR_TOP.  On processors that override the default FIXADDR_TOP
address of 0xfffe_0000, this can consume up to 4 pages (1 page per 4MB)
for pgd's that are never used.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1980/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

BMIPS4350/4380/5000 CMT/SMT all use SW INT0/INT1 for inter-thread
signaling.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1709/Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Memory maps and addressing quirks are normally defined in <spaces.h>.
There are already three targets that need to override FIXADDR_TOP, and
others exist.  This will be a cleaner approach than adding lots of
ifdefs in fixmap.h .
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1573/Acked-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>