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  1. Nov 30, 2016
  3. Oct 15, 2016
  5. Oct 14, 2016
  7. Oct 12, 2016
  9. Oct 11, 2016
  11. Oct 10, 2016
    • Emese Revfy's avatar
      gcc-plugins: Add latent_entropy plugin · 38addce8
      Emese Revfy authored 
      

This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).

At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.

The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).

To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).

Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.

Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.

Signed-off-by: default avatarEmese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      38addce8
    • Paul Burton's avatar
      MIPS: Enable hardened usercopy · cabca8c0
      Paul Burton authored 
      

Enable CONFIG_HARDENED_USERCOPY checks for MIPS, calling check_object
size in all of copy_{to,from}_user(), __copy_{to,from}_user() &
__copy_{to,from}_user_inatomic().

Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14371/


Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
      cabca8c0
  13. Oct 09, 2016
  15. Oct 08, 2016
    • Paul Gortmaker's avatar
      parisc: Migrate exception table users off module.h and onto extable.h · a38671d6
      Paul Gortmaker authored 
      

This file was only including module.h for exception table related
functions.  We've now separated that content out into its own file
"extable.h" so now move over to that and avoid all the extra header
content in module.h that we don't really need to compile this file.

Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Signed-off-by: default avatarPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
      a38671d6
    • Dave Hansen's avatar
      x86/pkeys: Make protection keys an "eager" feature · d4b05923
      Dave Hansen authored 
      

Our XSAVE features are divided into two categories: those that
generate FPU exceptions, and those that do not.  MPX and pkeys do
not generate FPU exceptions and thus can not be used lazily.  We
disable them when lazy mode is forced on.

We have a pair of masks to collect these two sets of features, but
XFEATURE_MASK_PKRU was added to the wrong mask: XFEATURE_MASK_LAZY.
Fix it by moving the feature to XFEATURE_MASK_EAGER.

Note: this only causes problem if you boot with lazy FPU mode
(eagerfpu=off) which is *not* the default.  It also only affects
hardware which is not currently publicly available.  It looks like
eager mode is going away, but we still need this patch applied
to any kernel that has protection keys and lazy mode, which is 4.6
through 4.8 at this point, and 4.9 if the lazy removal isn't sent
to Linus for 4.9.

Fixes: c8df4009 ("x86/fpu, x86/mm/pkeys: Add PKRU xsave fields and data structures")
Signed-off-by: default avatarDave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20161007162342.28A49813@viggo.jf.intel.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      d4b05923
    • Thomas Gleixner's avatar
      x86/apic: Prevent pointless warning messages · df610d67
      Thomas Gleixner authored 
      

Markus reported that he sees new warnings:

  APIC: NR_CPUS/possible_cpus limit of 4 reached.  Processor 4/0x84 ignored.
  APIC: NR_CPUS/possible_cpus limit of 4 reached.  Processor 5/0x85 ignored.

This comes from the recent persistant cpuid - nodeid changes. The code
which emits the warning has been called prior to these changes only for
enabled processors. Now it's called for disabled processors as well to get
the possible cpu accounting correct. So if the kernel is compiled for the
number of actual available/enabled CPUs and the BIOS reports disabled CPUs
as well then the above warnings are printed.

That's a pointless exercise as it only makes sense if there are more CPUs
enabled than the kernel supports.

Nake the warning conditional on enabled processors so we are back to the
state before these changes.

Fixes: 8f54969d ("x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping") 
Reported-and-tested-by: default avatarMarkus Trippelsdorf <markus@trippelsdorf.de>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
Cc: linux-acpi@vger.kernel.org
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610071549330.19804@nanos


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      df610d67
    • Thomas Gleixner's avatar
      x86/acpi: Prevent LAPIC id 0xff from being accounted · f3bf1dbe
      Thomas Gleixner authored 
      

Yinghai reported that the recent changes to make the cpuid - nodeid
relationship permanent causes a cpuid ordering regression on a system which
has 2apic enabled..

The reason is that the ACPI local APIC parser has no sanity check for
apicid 0xff, which is an invalid id. So a CPU id for this invalid local
APIC id is allocated and therefor breaks the cpuid ordering.

Add a sanity check to acpi_parse_lapic() which ignores the invalid id.

Fixes: 8f54969d ("x86/acpi: Introduce persistent storage for cpuid <-> apicid mapping")
Reported-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>,
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: douly.fnst@cn.fujitsu.com,
Cc: zhugh.fnst@cn.fujitsu.com
Cc: Tony Luck <tony.luck@intel.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Lv Zheng <lv.zheng@intel.com>,
Cc: robert.moore@intel.com
Cc: linux-acpi@vger.kernel.org
Link: https://lkml.kernel.org/r/CAE9FiQVQx6FRXT-RdR7Crz4dg5LeUWHcUSy1KacjR+JgU_vGJg@mail.gmail.com
      f3bf1dbe
    • Alexey Dobriyan's avatar
      cred: simpler, 1D supplementary groups · 81243eac
      Alexey Dobriyan authored 
      Current supplementary groups code can massively overallocate memory and
is implemented in a way so that access to individual gid is done via 2D
array.

If number of gids is <= 32, memory allocation is more or less tolerable
(140/148 bytes).  But if it is not, code allocates full page (!)
regardless and, what's even more fun, doesn't reuse small 32-entry
array.

2D array means dependent shifts, loads and LEAs without possibility to
optimize them (gid is never known at compile time).

All of the above is unnecessary.  Switch to the usual
trailing-zero-len-array scheme.  Memory is allocated with
kmalloc/vmalloc() and only as much as needed.  Accesses become simpler
(LEA 8(gi,idx,4) or even without displacement).

Maximum number of gids is 65536 which translates to 256KB+8 bytes.  I
think kernel can handle such allocation.

On my usual desktop system with whole 9 (nine) aux groups, struct
group_info shrinks from 148 bytes to 44 bytes, yay!

Nice side effects:

 - "gi->gid[i]" is shorter than "GROUP_AT(gi, i)", less typing,

 - fix little mess in net/ipv4/ping.c
   should have been using GROUP_AT macro but this point becomes moot,

 - aux group allocation is persistent and should be accounted as such.

Link: http://lkml.kernel.org/r/20160817201927.GA2096@p183.telecom.by


Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      81243eac
    • Marcin Nowakowski's avatar
      uprobes: remove function declarations from arch/{mips,s390} · ea036230
      Marcin Nowakowski authored 
      The declarations of arch-specific functions have been moved to a common
header in commit 3820b4d2 ('uprobes: Move function declarations out
of arch'), but MIPS and S390 has added them to their own trees later.
Remove the unnecessary duplicates.

Link: http://lkml.kernel.org/r/1472804384-17830-1-git-send-email-marcin.nowakowski@imgtec.com


Signed-off-by: default avatarMarcin Nowakowski <marcin.nowakowski@imgtec.com>
Acked-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ea036230
    • Chris Metcalf's avatar
      nmi_backtrace: generate one-line reports for idle cpus · 6727ad9e
      Chris Metcalf authored 
      When doing an nmi backtrace of many cores, most of which are idle, the
output is a little overwhelming and very uninformative.  Suppress
messages for cpus that are idling when they are interrupted and just
emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".

We do this by grouping all the cpuidle code together into a new
.cpuidle.text section, and then checking the address of the interrupted
PC to see if it lies within that section.

This commit suitably tags x86 and tile idle routines, and only adds in
the minimal framework for other architectures.

Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com


Signed-off-by: default avatarChris Metcalf <cmetcalf@mellanox.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Tested-by: default avatarPetr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6727ad9e
    • Chris Metcalf's avatar
      arch/tile: adopt the new nmi_backtrace framework · 511f8389
      Chris Metcalf authored 
      Previously tile was rolling its own method of capturing backtrace data
in the NMI handlers, but it was relying on running printk() from the NMI
handler, which is not always safe.  So adopt the nmi_backtrace model
(with the new cpumask extension) instead.

So we can call the nmi_backtrace code directly from the nmi handler,
move the nmi_enter()/exit() into the top-level tile NMI handler.

The semantics of the routine change slightly since it is now synchronous
with the remote cores completing the backtraces.  Previously it was
asynchronous, but with protection to avoid starting a new remote
backtrace if the old one was still in progress.

Link: http://lkml.kernel.org/r/1472487169-14923-4-git-send-email-cmetcalf@mellanox.com


Signed-off-by: default avatarChris Metcalf <cmetcalf@mellanox.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Cc: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      511f8389
    • Chris Metcalf's avatar
      nmi_backtrace: do a local dump_stack() instead of a self-NMI · 67766489
      Chris Metcalf authored 
      Currently on arm there is code that checks whether it should call
dump_stack() explicitly, to avoid trying to raise an NMI when the
current context is not preemptible by the backtrace IPI.  Similarly, the
forthcoming arch/tile support uses an IPI mechanism that does not
support generating an NMI to self.

Accordingly, move the code that guards this case into the generic
mechanism, and invoke it unconditionally whenever we want a backtrace of
the current cpu.  It seems plausible that in all cases, dump_stack()
will generate better information than generating a stack from the NMI
handler.  The register state will be missing, but that state is likely
not particularly helpful in any case.

Or, if we think it is helpful, we should be capturing and emitting the
current register state in all cases when regs == NULL is passed to
nmi_cpu_backtrace().

Link: http://lkml.kernel.org/r/1472487169-14923-3-git-send-email-cmetcalf@mellanox.com


Signed-off-by: default avatarChris Metcalf <cmetcalf@mellanox.com>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Acked-by: default avatarAaron Tomlin <atomlin@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      67766489
    • Chris Metcalf's avatar
      nmi_backtrace: add more trigger_*_cpu_backtrace() methods · 9a01c3ed
      Chris Metcalf authored 
      Patch series "improvements to the nmi_backtrace code" v9.

This patch series modifies the trigger_xxx_backtrace() NMI-based remote
backtracing code to make it more flexible, and makes a few small
improvements along the way.

The motivation comes from the task isolation code, where there are
scenarios where we want to be able to diagnose a case where some cpu is
about to interrupt a task-isolated cpu.  It can be helpful to see both
where the interrupting cpu is, and also an approximation of where the
cpu that is being interrupted is.  The nmi_backtrace framework allows us
to discover the stack of the interrupted cpu.

I've tested that the change works as desired on tile, and build-tested
x86, arm, mips, and sparc64.  For x86 I confirmed that the generic
cpuidle stuff as well as the architecture-specific routines are in the
new cpuidle section.  For arm, mips, and sparc I just build-tested it
and made sure the generic cpuidle routines were in the new cpuidle
section, but I didn't attempt to figure out which the platform-specific
idle routines might be.  That might be more usefully done by someone
with platform experience in follow-up patches.

This patch (of 4):

Currently you can only request a backtrace of either all cpus, or all
cpus but yourself.  It can also be helpful to request a remote backtrace
of a single cpu, and since we want that, the logical extension is to
support a cpumask as the underlying primitive.

This change modifies the existing lib/nmi_backtrace.c code to take a
cpumask as its basic primitive, and modifies the linux/nmi.h code to use
the new "cpumask" method instead.

The existing clients of nmi_backtrace (arm and x86) are converted to
using the new cpumask approach in this change.

The other users of the backtracing API (sparc64 and mips) are converted
to use the cpumask approach rather than the all/allbutself approach.
The mips code ignored the "include_self" boolean but with this change it
will now also dump a local backtrace if requested.

Link: http://lkml.kernel.org/r/1472487169-14923-2-git-send-email-cmetcalf@mellanox.com


Signed-off-by: default avatarChris Metcalf <cmetcalf@mellanox.com>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Reviewed-by: default avatarAaron Tomlin <atomlin@redhat.com>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9a01c3ed
    • Vineet Gupta's avatar
      atomic64: no need for CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE · 51a02124
      Vineet Gupta authored 
      This came to light when implementing native 64-bit atomics for ARCv2.

The atomic64 self-test code uses CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
to check whether atomic64_dec_if_positive() is available.  It seems it
was needed when not every arch defined it.  However as of current code
the Kconfig option seems needless

 - for CONFIG_GENERIC_ATOMIC64 it is auto-enabled in lib/Kconfig and a
   generic definition of API is present lib/atomic64.c
 - arches with native 64-bit atomics select it in arch/*/Kconfig and
   define the API in their headers

So I see no point in keeping the Kconfig option

Compile tested for:
 - blackfin (CONFIG_GENERIC_ATOMIC64)
 - x86 (!CONFIG_GENERIC_ATOMIC64)
 - ia64

Link: http://lkml.kernel.org/r/1473703083-8625-3-git-send-email-vgupta@synopsys.com


Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      51a02124
    • Vineet Gupta's avatar
      ia64: implement atomic64_dec_if_positive · 445ed0a0
      Vineet Gupta authored 
      This is based on s390 version and needed to get rid of
CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

Link: http://lkml.kernel.org/r/1473703083-8625-2-git-send-email-vgupta@synopsys.com


Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      445ed0a0