linux/arch, branch v3.4.27

xen: Fix stack corruption in xen_failsafe_callback for 32bit PVOPS guests.

2013-01-21T19:45:25Z

commit 9174adbee4a9a49d0139f5d71969852b36720809 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 Signed-off-by: Andrew Cooper Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

x86/Sandy Bridge: reserve pages when integrated graphics is present

2013-01-21T19:45:17Z

commit a9acc5365dbda29f7be2884efb63771dc24bd815 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 Signed-off-by: H. Peter Anvin Cc: CAI Qian Signed-off-by: Greg Kroah-Hartman

s390/time: fix sched_clock() overflow

2013-01-21T19:45:15Z

commit ed4f20943cd4c7b55105c04daedf8d63ab6d499c 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 Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

sh: Fix FDPIC binary loader

2013-01-21T19:45:14Z

commit 4a71997a3279a339e7336ea5d0cd27282e2dea44 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 d5ab780305bb6d60a7b5a74f18cf84eb6ad153b1. Signed-off-by: Thomas Schwinge Signed-off-by: Paul Mundt Signed-off-by: Greg Kroah-Hartman

KVM: PPC: 44x: fix DCR read/write

2013-01-17T16:51:06Z

commit e43a028752fed049e4bd94ef895542f96d79fa74 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 Signed-off-by: CAI Qian Signed-off-by: Greg Kroah-Hartman

ALSA: pxa27x: fix ac97 warm reset

2013-01-17T16:50:55Z

commit 3b4bc7bccc7857274705b05cf81a0c72cfd0b0dd upstream. This patch fixes some code that implements a work-around to a hardware bug in the ac97 controller on the pxa27x. A bug in the controller's warm reset functionality requires that the mfp used by the controller as the AC97_nRESET line be temporarily reconfigured as a generic output gpio (AF0) and manually held high for the duration of the warm reset cycle. This is what was done in the original code, but it was broken long ago by commit fb1bf8cd ([ARM] pxa: introduce processor specific pxa27x_assert_ac97reset()) which changed the mfp to a GPIO input instead of a high output. The fix requires the ac97 controller to obtain the gpio via gpio_request_one(), with arguments that configure the gpio as an output initially driven high. Tested on a palm treo 680 machine. Reportedly, this broken code only prevents a warm reset on hardware that lacks a pull-up on the line, which appears to be the case for me. Signed-off-by: Mike Dunn Signed-off-by: Igor Grinberg Signed-off-by: Mark Brown Signed-off-by: Greg Kroah-Hartman

x86, amd: Disable way access filter on Piledriver CPUs

2013-01-17T16:50:53Z

commit 2bbf0a1427c377350f001fbc6260995334739ad7 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 Link: http://lkml.kernel.org/r/1351700450-9277-1-git-send-email-osp@andrep.de Signed-off-by: H. Peter Anvin Signed-off-by: CAI Qian Signed-off-by: Greg Kroah-Hartman

MIPS: Fix poweroff failure when HOTPLUG_CPU configured.

2013-01-17T16:50:42Z

commit 8add1ecb81f541ef2fcb0b85a5470ad9ecfb4a84 upstream. When poweroff machine, kernel_power_off() call disable_nonboot_cpus(). And if we have HOTPLUG_CPU configured, disable_nonboot_cpus() is not an empty function but attempt to actually disable the nonboot cpus. Since system state is SYSTEM_POWER_OFF, play_dead() won't be called and thus disable_nonboot_cpus() hangs. Therefore, we make this patch to avoid poweroff failure. Signed-off-by: Huacai Chen Signed-off-by: Hongliang Tao Signed-off-by: Hua Yan Cc: Yong Zhang Cc: Fuxin Zhang Cc: Zhangjin Wu Patchwork: https://patchwork.linux-mips.org/patch/4211/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman

powerpc: Add missing NULL terminator to avoid boot panic on PPC40x

2013-01-17T16:50:42Z

commit e6449c9b2d90c1bd9a5985bf05ddebfd1631cd6b upstream. The missing NULL terminator can cause a panic on PPC405 boards during boot: Linux/PowerPC load: console=ttyS0,115200 root=/dev/mtdblock1 rootfstype=squashfs,jffs2 noinitrd init=/etc/preinit Finalizing device tree... flat tree at 0x6a5160 bootconsole [udbg0] enabled Page fault in user mode with in_atomic() = 1 mm = (null) NIP = c0275f50 MSR = fffffffe Oops: Weird page fault, sig: 11 [#1] PowerPC 40x Platform Modules linked in: NIP: c0275f50 LR: c0275f60 CTR: c0280000 REGS: c0275eb0 TRAP: 636f7265 Not tainted (3.7.1) MSR: fffffffe CR: c06a6190 XER: 00000001 TASK = c02662a8[0] 'swapper' THREAD: c0274000 GPR00: c0275ec0 c000c658 c027c4bf 00000000 c0275ee0 c000a0ec c020a1a8 c020a1f0 GPR08: c020f631 c020f404 c025f078 c025f080 c0275f10 Call Trace: ---[ end trace 31fd0ba7d8756001 ]--- Kernel panic - not syncing: Attempted to kill the idle task! The panic happens since commit 9597abe00c1bab2aedce6b49866bf6d1e81c9eed (sections: fix section conflicts in arch/powerpc), however the root cause of this is that the NULL terminator were not added in commit a4f740cf33f7f6c164bbde3c0cdbcc77b0c4997c (of/flattree: Add of_flat_dt_match() helper function). Signed-off-by: Gabor Juhos Cc: Grant Likely Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc/vdso: Remove redundant locking in update_vsyscall_tz()

2013-01-17T16:50:42Z

commit ce73ec6db47af84d1466402781ae0872a9e7873c 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 6c260d58634 ("x86: vdso: Remove bogus locking in update_vsyscall_tz") Signed-off-by: Shan Hai Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman