user/sven/linux.git/arch, branch v3.0.48

x86, random: Verify RDRAND functionality and allow it to be disabled

2012-10-21T16:17:12Z

commit 49d859d78c5aeb998b6936fcb5f288f78d713489 upstream. If the CPU declares that RDRAND is available, go through a guranteed reseed sequence, and make sure that it is actually working (producing data.) If it does not, disable the CPU feature flag. Allow RDRAND to be disabled on the command line (as opposed to at compile time) for a user who has special requirements with regards to random numbers. Signed-off-by: H. Peter Anvin Cc: Matt Mackall Cc: Herbert Xu Cc: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman

x86, random: Architectural inlines to get random integers with RDRAND

2012-10-21T16:17:12Z

commit 628c6246d47b85f5357298601df2444d7f4dd3fd upstream. Architectural inlines to get random ints and longs using the RDRAND instruction. Intel has introduced a new RDRAND instruction, a Digital Random Number Generator (DRNG), which is functionally an high bandwidth entropy source, cryptographic whitener, and integrity monitor all built into hardware. This enables RDRAND to be used directly, bypassing the kernel random number pool. For technical documentation, see: http://software.intel.com/en-us/articles/download-the-latest-bull-mountain-software-implementation-guide/ In this patch, this is *only* used for the nonblocking random number pool. RDRAND is a nonblocking source, similar to our /dev/urandom, and is therefore not a direct replacement for /dev/random. The architectural hooks presented in the previous patch only feed the kernel internal users, which only use the nonblocking pool, and so this is not a problem. Since this instruction is available in userspace, there is no reason to have a /dev/hw_rng device driver for the purpose of feeding rngd. This is especially so since RDRAND is a nonblocking source, and needs additional whitening and reduction (see the above technical documentation for details) in order to be of "pure entropy source" quality. The CONFIG_EXPERT compile-time option can be used to disable this use of RDRAND. Signed-off-by: H. Peter Anvin Originally-by: Fenghua Yu Cc: Matt Mackall Cc: Herbert Xu Cc: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman

xen/bootup: allow read_tscp call for Xen PV guests.

2012-10-21T16:17:10Z

commit cd0608e71e9757f4dae35bcfb4e88f4d1a03a8ab upstream. The hypervisor will trap it. However without this patch, we would crash as the .read_tscp is set to NULL. This patch fixes it and sets it to the native_read_tscp call. Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

xen/bootup: allow {read|write}_cr8 pvops call.

2012-10-21T16:17:10Z

commit 1a7bbda5b1ab0e02622761305a32dc38735b90b2 upstream. We actually do not do anything about it. Just return a default value of zero and if the kernel tries to write anything but 0 we BUG_ON. This fixes the case when an user tries to suspend the machine and it blows up in save_processor_state b/c 'read_cr8' is set to NULL and we get: kernel BUG at /home/konrad/ssd/linux/arch/x86/include/asm/paravirt.h:100! invalid opcode: 0000 [#1] SMP Pid: 2687, comm: init.late Tainted: G O 3.6.0upstream-00002-gac264ac-dirty #4 Bochs Bochs RIP: e030:[] [] save_processor_state+0x212/0x270 .. snip.. Call Trace: [] do_suspend_lowlevel+0xf/0xac [] ? x86_acpi_suspend_lowlevel+0x10c/0x150 [] acpi_suspend_enter+0x57/0xd5 Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

ARM: 7541/1: Add ARM ERRATA 775420 workaround

2012-10-21T16:17:10Z

commit 7253b85cc62d6ff84143d96fe6cd54f73736f4d7 upstream. arm: Add ARM ERRATA 775420 workaround Workaround for the 775420 Cortex-A9 (r2p2, r2p6,r2p8,r2p10,r3p0) erratum. In case a date cache maintenance operation aborts with MMU exception, it might cause the processor to deadlock. This workaround puts DSB before executing ISB if an abort may occur on cache maintenance. Based on work by Kouei Abe and feedback from Catalin Marinas. Signed-off-by: Kouei Abe [ horms@verge.net.au: Changed to implementation suggested by catalin.marinas@arm.com ] Acked-by: Catalin Marinas Signed-off-by: Simon Horman Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman

mips,kgdb: fix recursive page fault with CONFIG_KPROBES

2012-10-21T16:17:10Z

commit f0a996eeeda214f4293e234df33b29bec003b536 upstream. This fault was detected using the kgdb test suite on boot and it crashes recursively due to the fact that CONFIG_KPROBES on mips adds an extra die notifier in the page fault handler. The crash signature looks like this: kgdbts:RUN bad memory access test KGDB: re-enter exception: ALL breakpoints killed Call Trace: [<807b7548>] dump_stack+0x20/0x54 [<807b7548>] dump_stack+0x20/0x54 The fix for now is to have kgdb return immediately if the fault type is DIE_PAGE_FAULT and allow the kprobe code to decide what is supposed to happen. Signed-off-by: Jason Wessel Cc: Masami Hiramatsu Cc: David S. Miller Signed-off-by: Greg Kroah-Hartman

ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels

2012-10-21T16:17:09Z

commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 upstream. Michael Olbrich reported that his test program fails when built with -O2 -mcpu=cortex-a8 -mfpu=neon, and a kernel which supports v6 and v7 CPUs: volatile int x = 2; volatile int64_t y = 2; int main() { volatile int a = 0; volatile int64_t b = 0; while (1) { a = (a + x) % (1 << 30); b = (b + y) % (1 << 30); assert(a == b); } } and two instances are run. When built for just v7 CPUs, this program works fine. It uses the "vadd.i64 d19, d18, d16" VFP instruction. It appears that we do not save the high-16 double VFP registers across context switches when the kernel is built for v6 CPUs. Fix that. Tested-By: Michael Olbrich Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman

mm: thp: fix pmd_present for split_huge_page and PROT_NONE with THP

2012-10-12T20:28:10Z

commit 027ef6c87853b0a9df53175063028edb4950d476 upstream. In many places !pmd_present has been converted to pmd_none. For pmds that's equivalent and pmd_none is quicker so using pmd_none is better. However (unless we delete pmd_present) we should provide an accurate pmd_present too. This will avoid the risk of code thinking the pmd is non present because it's under __split_huge_page_map, see the pmd_mknotpresent there and the comment above it. If the page has been mprotected as PROT_NONE, it would also lead to a pmd_present false negative in the same way as the race with split_huge_page. Because the PSE bit stays on at all times (both during split_huge_page and when the _PAGE_PROTNONE bit get set), we could only check for the PSE bit, but checking the PROTNONE bit too is still good to remember pmd_present must always keep PROT_NONE into account. This explains a not reproducible BUG_ON that was seldom reported on the lists. The same issue is in pmd_large, it would go wrong with both PROT_NONE and if it races with split_huge_page. Signed-off-by: Andrea Arcangeli Acked-by: Rik van Riel Cc: Johannes Weiner Cc: Hugh Dickins Cc: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mn10300: only add -mmem-funcs to KBUILD_CFLAGS if gcc supports it

2012-10-12T20:28:02Z

commit 9957423f035c2071f6d1c5d2f095cdafbeb25ad7 upstream. It seems the current (gcc 4.6.3) no longer provides this so make it conditional. As reported by Tony before, the mn10300 architecture cross-compiles with gcc-4.6.3 if -mmem-funcs is not added to KBUILD_CFLAGS. Reported-by: Tony Breeds Signed-off-by: Geert Uytterhoeven Cc: David Howells Cc: Koichi Yasutake Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

x86/alternatives: Fix p6 nops on non-modular kernels

2012-10-07T15:27:27Z

commit cb09cad44f07044d9810f18f6f9a6a6f3771f979 upstream. Probably a leftover from the early days of self-patching, p6nops are marked __initconst_or_module, which causes them to be discarded in a non-modular kernel. If something later triggers patching, it will overwrite kernel code with garbage. Reported-by: Tomas Racek Signed-off-by: Avi Kivity Cc: Michael Tokarev Cc: Borislav Petkov Cc: Marcelo Tosatti Cc: qemu-devel@nongnu.org Cc: Anthony Liguori Cc: H. Peter Anvin Cc: Alan Cox Cc: Alan Cox Link: http://lkml.kernel.org/r/5034AE84.90708@redhat.com Signed-off-by: Ingo Molnar Cc: Ben Jencks Signed-off-by: Greg Kroah-Hartman