linux-stable.git/arch, branch v4.14.76

ARC: clone syscall to setp r25 as thread pointer

2018-10-13T07:27:28+00:00

commit c58a584f05e35d1d4342923cd7aac07d9c3d3d16 upstream.

Per ARC TLS ABI, r25 is designated TP (thread pointer register).
However so far kernel didn't do any special treatment, like setting up
usermode r25, even for CLONE_SETTLS. We instead relied on libc runtime
to do this, in say clone libc wrapper [1]. This was deliberate to keep
kernel ABI agnostic (userspace could potentially change TP, specially
for different ARC ISA say ARCompact vs. ARCv2 with different spare
registers etc)

However userspace setting up r25, after clone syscall opens a race, if
child is not scheduled and gets a signal instead. It starts off in
userspace not in clone but in a signal handler and anything TP sepcific
there such as pthread_self() fails which showed up with uClibc
testsuite nptl/tst-kill6 [2]

Fix this by having kernel populate r25 to TP value. So this locks in
ABI, but it was not going to change anyways, and fwiw is same for both
ARCompact (arc700 core) and ARCvs (HS3x cores)

[1] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/arc/clone.S
[2] https://github.com/wbx-github/uclibc-ng-test/blob/master/test/nptl/tst-kill6.c

Fixes: ARC STAR 9001378481
Cc: stable@vger.kernel.org
Reported-by: Nikita Sobolev 
Signed-off-by: Vineet Gupta 
Signed-off-by: Greg Kroah-Hartman

powerpc/lib: fix book3s/32 boot failure due to code patching

2018-10-13T07:27:28+00:00

commit b45ba4a51cde29b2939365ef0c07ad34c8321789 upstream.

Commit 51c3c62b58b3 ("powerpc: Avoid code patching freed init
sections") accesses 'init_mem_is_free' flag too early, before the
kernel is relocated. This provokes early boot failure (before the
console is active).

As it is not necessary to do this verification that early, this
patch moves the test into patch_instruction() instead of
__patch_instruction().

This modification also has the advantage of avoiding unnecessary
remappings.

Fixes: 51c3c62b58b3 ("powerpc: Avoid code patching freed init sections")
Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc: Avoid code patching freed init sections

2018-10-13T07:27:28+00:00

commit 51c3c62b58b357e8d35e4cc32f7b4ec907426fe3 upstream.

This stops us from doing code patching in init sections after they've
been freed.

In this chain:
  kvm_guest_init() ->
    kvm_use_magic_page() ->
      fault_in_pages_readable() ->
	 __get_user() ->
	   __get_user_nocheck() ->
	     barrier_nospec();

We have a code patching location at barrier_nospec() and
kvm_guest_init() is an init function. This whole chain gets inlined,
so when we free the init section (hence kvm_guest_init()), this code
goes away and hence should no longer be patched.

We seen this as userspace memory corruption when using a memory
checker while doing partition migration testing on powervm (this
starts the code patching post migration via
/sys/kernel/mobility/migration). In theory, it could also happen when
using /sys/kernel/debug/powerpc/barrier_nospec.

Cc: stable@vger.kernel.org # 4.13+
Signed-off-by: Michael Neuling 
Reviewed-by: Nicholas Piggin 
Reviewed-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

powerpc/lib/code-patching: refactor patch_instruction()

2018-10-13T07:27:28+00:00

commit 8cf4c05712f04a405f0dacebcca8f042b391694a upstream.

patch_instruction() uses almost the same sequence as
__patch_instruction()

This patch refactor it so that patch_instruction() uses
__patch_instruction() instead of duplicating code.

Signed-off-by: Christophe Leroy 
Acked-by: Balbir Singh 
Signed-off-by: Michael Ellerman 
Signed-off-by: Greg Kroah-Hartman

x86/vdso: Fix vDSO syscall fallback asm constraint regression

2018-10-13T07:27:24+00:00

commit 02e425668f5c9deb42787d10001a3b605993ad15 upstream.

When I added the missing memory outputs, I failed to update the
index of the first argument (ebx) on 32-bit builds, which broke the
fallbacks.  Somehow I must have screwed up my testing or gotten
lucky.

Add another test to cover gettimeofday() as well.

Signed-off-by: Andy Lutomirski 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: stable@vger.kernel.org
Fixes: 715bd9d12f84 ("x86/vdso: Fix asm constraints on vDSO syscall fallbacks")
Link: http://lkml.kernel.org/r/21bd45ab04b6d838278fa5bebfa9163eceffa13c.1538608971.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/vdso: Only enable vDSO retpolines when enabled and supported

2018-10-13T07:27:24+00:00

commit 4f166564014aba65ad6f15b612f6711fd0f117ee upstream.

When I fixed the vDSO build to use inline retpolines, I messed up
the Makefile logic and made it unconditional.  It should have
depended on CONFIG_RETPOLINE and on the availability of compiler
support.  This broke the build on some older compilers.

Reported-by: nikola.ciprich@linuxbox.cz
Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: David Woodhouse 
Cc: Linus Torvalds 
Cc: Matt Rickard 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: jason.vas.dias@gmail.com
Cc: stable@vger.kernel.org
Fixes: 2e549b2ee0e3 ("x86/vdso: Fix vDSO build if a retpoline is emitted")
Link: http://lkml.kernel.org/r/08a1f29f2c238dd1f493945e702a521f8a5aa3ae.1538540801.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/vdso: Fix asm constraints on vDSO syscall fallbacks

2018-10-13T07:27:23+00:00

commit 715bd9d12f84d8f5cc8ad21d888f9bc304a8eb0b upstream.

The syscall fallbacks in the vDSO have incorrect asm constraints.
They are not marked as writing to their outputs -- instead, they are
marked as clobbering "memory", which is useless.  In particular, gcc
is smart enough to know that the timespec parameter hasn't escaped,
so a memory clobber doesn't clobber it.  And passing a pointer as an
asm *input* does not tell gcc that the pointed-to value is changed.

Add in the fact that the asm instructions weren't volatile, and gcc
was free to omit them entirely unless their sole output (the return
value) is used.  Which it is (phew!), but that stops happening with
some upcoming patches.

As a trivial example, the following code:

void test_fallback(struct timespec *ts)
{
	vdso_fallback_gettime(CLOCK_MONOTONIC, ts);
}

compiles to:

00000000000000c0 :
  c0:   c3                      retq

To add insult to injury, the RCX and R11 clobbers on 64-bit
builds were missing.

The "memory" clobber is also unnecessary -- no ordering with respect to
other memory operations is needed, but that's going to be fixed in a
separate not-for-stable patch.

Fixes: 2aae950b21e4 ("x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu")
Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/2c0231690551989d2fafa60ed0e7b5cc8b403908.1538422295.git.luto@kernel.org
Signed-off-by: Greg Kroah-Hartman

KVM: x86: fix L1TF's MMIO GFN calculation

2018-10-13T07:27:22+00:00

commit daa07cbc9ae3da2d61b7ce900c0b9107d134f2c1 upstream.

One defense against L1TF in KVM is to always set the upper five bits
of the *legal* physical address in the SPTEs for non-present and
reserved SPTEs, e.g. MMIO SPTEs.  In the MMIO case, the GFN of the
MMIO SPTE may overlap with the upper five bits that are being usurped
to defend against L1TF.  To preserve the GFN, the bits of the GFN that
overlap with the repurposed bits are shifted left into the reserved
bits, i.e. the GFN in the SPTE will be split into high and low parts.
When retrieving the GFN from the MMIO SPTE, e.g. to check for an MMIO
access, get_mmio_spte_gfn() unshifts the affected bits and restores
the original GFN for comparison.  Unfortunately, get_mmio_spte_gfn()
neglects to mask off the reserved bits in the SPTE that were used to
store the upper chunk of the GFN.  As a result, KVM fails to detect
MMIO accesses whose GPA overlaps the repurprosed bits, which in turn
causes guest panics and hangs.

Fix the bug by generating a mask that covers the lower chunk of the
GFN, i.e. the bits that aren't shifted by the L1TF mitigation.  The
alternative approach would be to explicitly zero the five reserved
bits that are used to store the upper chunk of the GFN, but that
requires additional run-time computation and makes an already-ugly
bit of code even more inscrutable.

I considered adding a WARN_ON_ONCE(low_phys_bits-1 <= PAGE_SHIFT) to
warn if GENMASK_ULL() generated a nonsensical value, but that seemed
silly since that would mean a system that supports VMX has less than
18 bits of physical address space...

Reported-by: Sakari Ailus 
Fixes: d9b47449c1a1 ("kvm: x86: Set highest physical address bits in non-present/reserved SPTEs")
Cc: Junaid Shahid 
Cc: Jim Mattson 
Cc: stable@vger.kernel.org
Reviewed-by: Junaid Shahid 
Tested-by: Sakari Ailus 
Signed-off-by: Sean Christopherson 
Signed-off-by: Paolo Bonzini 
Signed-off-by: Greg Kroah-Hartman

arm64: jump_label.h: use asm_volatile_goto macro instead of "asm goto"

2018-10-10T06:54:25+00:00

[ Upstream commit 13aceef06adfaf93d52e01e28a8bc8a0ad471d83 ]

All other uses of "asm goto" go through asm_volatile_goto, which avoids
a miscompile when using GCC < 4.8.2. Replace our open-coded "asm goto"
statements with the asm_volatile_goto macro to avoid issues with older
toolchains.

Cc: Catalin Marinas 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Miguel Ojeda 
Signed-off-by: Will Deacon 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

hexagon: modify ffs() and fls() to return int

2018-10-10T06:54:25+00:00

[ Upstream commit 5c41aaad409c097cf1ef74f2c649fed994744ef5 ]

Building drivers/mtd/nand/raw/nandsim.c on arch/hexagon/ produces a
printk format build warning.  This is due to hexagon's ffs() being
coded as returning long instead of int.

Fix the printk format warning by changing all of hexagon's ffs() and
fls() functions to return int instead of long.  The variables that
they return are already int instead of long.  This return type
matches the return type in .

../drivers/mtd/nand/raw/nandsim.c: In function 'init_nandsim':
../drivers/mtd/nand/raw/nandsim.c:760:2: warning: format '%u' expects argument of type 'unsigned int', but argument 2 has type 'long int' [-Wformat]

There are no ffs() or fls() allmodconfig build errors after making this
change.

Signed-off-by: Randy Dunlap 
Cc: Richard Kuo 
Cc: linux-hexagon@vger.kernel.org
Cc: Geert Uytterhoeven 
Patch-mainline: linux-kernel @ 07/22/2018, 16:03
Signed-off-by: Richard Kuo 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman