commit 9174adbee4 upstream.
This fixes CVE-2013-0190 / XSA-40
There has been an error on the xen_failsafe_callback path for failed
iret, which causes the stack pointer to be wrong when entering the
iret_exc error path. This can result in the kernel crashing.
In the classic kernel case, the relevant code looked a little like:
popl %eax # Error code from hypervisor
jz 5f
addl $16,%esp
jmp iret_exc # Hypervisor said iret fault
5: addl $16,%esp
# Hypervisor said segment selector fault
Here, there are two identical addls on either option of a branch which
appears to have been optimised by hoisting it above the jz, and
converting it to an lea, which leaves the flags register unaffected.
In the PVOPS case, the code looks like:
popl_cfi %eax # Error from the hypervisor
lea 16(%esp),%esp # Add $16 before choosing fault path
CFI_ADJUST_CFA_OFFSET -16
jz 5f
addl $16,%esp # Incorrectly adjust %esp again
jmp iret_exc
It is possible unprivileged userspace applications to cause this
behaviour, for example by loading an LDT code selector, then changing
the code selector to be not-present. At this point, there is a race
condition where it is possible for the hypervisor to return back to
userspace from an interrupt, fault on its own iret, and inject a
failsafe_callback into the kernel.
This bug has been present since the introduction of Xen PVOPS support
in commit 5ead97c84 (xen: Core Xen implementation), in 2.6.23.
Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[not upstream as the code involved was removed in the 3.3.0 release]
Fix wii_memory_fixups() the following compile error on 3.0.y tree with
wii_defconfig on 3.0.y tree.
CC arch/powerpc/platforms/embedded6xx/wii.o
arch/powerpc/platforms/embedded6xx/wii.c: In function ‘wii_memory_fixups’:
arch/powerpc/platforms/embedded6xx/wii.c:88:2: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 2 has type ‘phys_addr_t’ [-Werror=format]
arch/powerpc/platforms/embedded6xx/wii.c:88:2: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘phys_addr_t’ [-Werror=format]
arch/powerpc/platforms/embedded6xx/wii.c:90:2: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 2 has type ‘phys_addr_t’ [-Werror=format]
arch/powerpc/platforms/embedded6xx/wii.c:90:2: error: format ‘%llx’ expects argument of type ‘long long unsigned int’, but argument 3 has type ‘phys_addr_t’ [-Werror=format]
cc1: all warnings being treated as errors
make[2]: *** [arch/powerpc/platforms/embedded6xx/wii.o] Error 1
make[1]: *** [arch/powerpc/platforms/embedded6xx] Error 2
make: *** [arch/powerpc/platforms] Error 2
Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a9acc5365d upstream.
SNB graphics devices have a bug that prevent them from accessing certain
memory ranges, namely anything below 1M and in the pages listed in the
table. So reserve those at boot if set detect a SNB gfx device on the
CPU to avoid GPU hangs.
Stephane Marchesin had a similar patch to the page allocator awhile
back, but rather than reserving pages up front, it leaked them at
allocation time.
[ hpa: made a number of stylistic changes, marked arrays as static
const, and made less verbose; use "memblock=debug" for full
verbosity. ]
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ed4f20943c upstream.
Converting a 64 Bit TOD format value to nanoseconds means that the value
must be divided by 4.096. In order to achieve that we multiply with 125
and divide by 512.
When used within sched_clock() this triggers an overflow after appr.
417 days. Resulting in a sched_clock() return value that is much smaller
than previously and therefore may cause all sort of weird things in
subsystems that rely on a monotonic sched_clock() behaviour.
To fix this implement a tod_to_ns() helper function which converts TOD
values without overflow and call this function from both places that
open coded the conversion: sched_clock() and kvm_s390_handle_wait().
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 4a71997a32 upstream.
Ensure that the aux table is properly initialized, even when optional features
are missing. Without this, the FDPIC loader did not work. This was meant to
be included in commit d5ab780305.
Signed-off-by: Thomas Schwinge <thomas@codesourcery.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e43a028752 upstream.
When remembering the direction of a DCR transaction, we should write
to the same variable that we interpret on later when doing vcpu_run
again.
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2bbf0a1427 upstream.
The Way Access Filter in recent AMD CPUs may hurt the performance of
some workloads, caused by aliasing issues in the L1 cache.
This patch disables it on the affected CPUs.
The issue is similar to that one of last year:
http://lkml.indiana.edu/hypermail/linux/kernel/1107.3/00041.html
This new patch does not replace the old one, we just need another
quirk for newer CPUs.
The performance penalty without the patch depends on the
circumstances, but is a bit less than the last year's 3%.
The workloads affected would be those that access code from the same
physical page under different virtual addresses, so different
processes using the same libraries with ASLR or multiple instances of
PIE-binaries. The code needs to be accessed simultaneously from both
cores of the same compute unit.
More details can be found here:
http://developer.amd.com/Assets/SharedL1InstructionCacheonAMD15hCPU.pdf
CPUs affected are anything with the core known as Piledriver.
That includes the new parts of the AMD A-Series (aka Trinity) and the
just released new CPUs of the FX-Series (aka Vishera).
The model numbering is a bit odd here: FX CPUs have model 2,
A-Series has model 10h, with possible extensions to 1Fh. Hence the
range of model ids.
Signed-off-by: Andre Przywara <osp@andrep.de>
Link: http://lkml.kernel.org/r/1351700450-9277-1-git-send-email-osp@andrep.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ce73ec6db4 upstream.
The locking in update_vsyscall_tz() is not only unnecessary because the vdso
code copies the data unproteced in __kernel_gettimeofday() but also
introduces a hard to reproduce race condition between update_vsyscall()
and update_vsyscall_tz(), which causes user space process to loop
forever in vdso code.
The following patch removes the locking from update_vsyscall_tz().
Locking is not only unnecessary because the vdso code copies the data
unprotected in __kernel_gettimeofday() but also erroneous because updating
the tb_update_count is not atomic and introduces a hard to reproduce race
condition between update_vsyscall() and update_vsyscall_tz(), which further
causes user space process to loop forever in vdso code.
The below scenario describes the race condition,
x==0 Boot CPU other CPU
proc_P: x==0
timer interrupt
update_vsyscall
x==1 x++;sync settimeofday
update_vsyscall_tz
x==2 x++;sync
x==3 sync;x++
sync;x++
proc_P: x==3 (loops until x becomes even)
Because the ++ operator would be implemented as three instructions and not
atomic on powerpc.
A similar change was made for x86 in commit 6c260d5863
("x86: vdso: Remove bogus locking in update_vsyscall_tz")
Signed-off-by: Shan Hai <shan.hai@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
