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2014-09-14x86, espfix: Make it possible to disable 16-bit supportH. Peter Anvin4-5/+43
commit 34273f41d57ee8d854dcd2a1d754cbb546cb548f upstream. Embedded systems, which may be very memory-size-sensitive, are extremely unlikely to ever encounter any 16-bit software, so make it a CONFIG_EXPERT option to turn off support for any 16-bit software whatsoever. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14x86, espfix: Make espfix64 a Kconfig option, fix UMLH. Peter Anvin3-2/+6
commit 197725de65477bc8509b41388157c1a2283542bb upstream. Make espfix64 a hidden Kconfig option. This fixes the x86-64 UML build which had broken due to the non-existence of init_espfix_bsp() in UML: since UML uses its own Kconfig, this option does not appear in the UML build. This also makes it possible to make support for 16-bit segments a configuration option, for the people who want to minimize the size of the kernel. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Richard Weinberger <richard@nod.at> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14x86, espfix: Fix broken header guardH. Peter Anvin1-1/+1
commit 20b68535cd27183ebd3651ff313afb2b97dac941 upstream. Header guard is #ifndef, not #ifdef... Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14x86, espfix: Move espfix definitions into a separate header fileH. Peter Anvin3-3/+19
commit e1fe9ed8d2a4937510d0d60e20705035c2609aea upstream. Sparse warns that the percpu variables aren't declared before they are defined. Rather than hacking around it, move espfix definitions into a proper header file. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14x86-64, espfix: Don't leak bits 31:16 of %esp returning to 16-bit stackH. Peter Anvin8-26/+318
commit 3891a04aafd668686239349ea58f3314ea2af86b upstream. The IRET instruction, when returning to a 16-bit segment, only restores the bottom 16 bits of the user space stack pointer. This causes some 16-bit software to break, but it also leaks kernel state to user space. We have a software workaround for that ("espfix") for the 32-bit kernel, but it relies on a nonzero stack segment base which is not available in 64-bit mode. In checkin: b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels we "solved" this by forbidding 16-bit segments on 64-bit kernels, with the logic that 16-bit support is crippled on 64-bit kernels anyway (no V86 support), but it turns out that people are doing stuff like running old Win16 binaries under Wine and expect it to work. This works around this by creating percpu "ministacks", each of which is mapped 2^16 times 64K apart. When we detect that the return SS is on the LDT, we copy the IRET frame to the ministack and use the relevant alias to return to userspace. The ministacks are mapped readonly, so if IRET faults we promote #GP to #DF which is an IST vector and thus has its own stack; we then do the fixup in the #DF handler. (Making #GP an IST exception would make the msr_safe functions unsafe in NMI/MC context, and quite possibly have other effects.) Special thanks to: - Andy Lutomirski, for the suggestion of using very small stack slots and copy (as opposed to map) the IRET frame there, and for the suggestion to mark them readonly and let the fault promote to #DF. - Konrad Wilk for paravirt fixup and testing. - Borislav Petkov for testing help and useful comments. Reported-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Andrew Lutomriski <amluto@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Dirk Hohndel <dirk@hohndel.org> Cc: Arjan van de Ven <arjan.van.de.ven@intel.com> Cc: comex <comexk@gmail.com> Cc: Alexander van Heukelum <heukelum@fastmail.fm> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option"H. Peter Anvin2-11/+1
commit 7ed6fb9b5a5510e4ef78ab27419184741169978a upstream. This reverts commit fa81511bb0bbb2b1aace3695ce869da9762624ff in preparation of merging in the proper fix (espfix64). Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14x86/xen: resume timer irqs earlyDavid Vrabel1-1/+1
commit 8d5999df35314607c38fbd6bdd709e25c3a4eeab upstream. If the timer irqs are resumed during device resume it is possible in certain circumstances for the resume to hang early on, before device interrupts are resumed. For an Ubuntu 14.04 PVHVM guest this would occur in ~0.5% of resume attempts. It is not entirely clear what is occuring the point of the hang but I think a task necessary for the resume calls schedule_timeout(), waiting for a timer interrupt (which never arrives). This failure may require specific tasks to be running on the other VCPUs to trigger (processes are not frozen during a suspend/resume if PREEMPT is disabled). Add IRQF_EARLY_RESUME to the timer interrupts so they are resumed in syscore_resume(). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14x86: don't exclude low BIOS area when allocating address space for non-PCI cardsChristoph Schulz2-3/+9
commit cbace46a9710a480cae51e4611697df5de41713e upstream. Commit 30919b0bf356 ("x86: avoid low BIOS area when allocating address space") moved the test for resource allocations that fall within the first 1MB of address space from the PCI-specific path to a generic path, such that all resource allocations will avoid this area. However, this breaks ISA cards which need to allocate a memory region within the first 1MB. An example is the i82365 PCMCIA controller and derivatives like the Ricoh RF5C296/396 which map part of the PCMCIA socket memory address space into the first 1MB of system memory address space. They do not work anymore as no usable memory region exists due to this change: Intel ISA PCIC probe: Ricoh RF5C296/396 ISA-to-PCMCIA at port 0x3e0 ofs 0x00, 2 sockets host opts [0]: none host opts [1]: none ISA irqs (scanned) = 3,4,5,9,10 status change on irq 10 pcmcia_socket pcmcia_socket1: pccard: PCMCIA card inserted into slot 1 pcmcia_socket pcmcia_socket0: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff pcmcia_socket pcmcia_socket0: cs: IO port probe 0xa00-0xaff: clean. pcmcia_socket pcmcia_socket0: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff pcmcia_socket pcmcia_socket0: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff pcmcia_socket pcmcia_socket0: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff pcmcia_socket pcmcia_socket0: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff pcmcia_socket pcmcia_socket0: cs: memory probe 0x0d0000-0x0dffff: clean. pcmcia_socket pcmcia_socket0: cs: memory probe 0x0e0000-0x0effff: clean. pcmcia_socket pcmcia_socket0: cs: memory probe 0x60000000-0x60ffffff: clean. pcmcia_socket pcmcia_socket0: cs: memory probe 0xa0000000-0xa0ffffff: clean. pcmcia_socket pcmcia_socket1: cs: IO port probe 0xc00-0xcff: excluding 0xcf8-0xcff pcmcia_socket pcmcia_socket1: cs: IO port probe 0xa00-0xaff: clean. pcmcia_socket pcmcia_socket1: cs: IO port probe 0x100-0x3ff: excluding 0x170-0x177 0x1f0-0x1f7 0x2f8-0x2ff 0x370-0x37f 0x3c0-0x3e7 0x3f0-0x3ff pcmcia_socket pcmcia_socket1: cs: memory probe 0x0a0000-0x0affff: excluding 0xa0000-0xaffff pcmcia_socket pcmcia_socket1: cs: memory probe 0x0b0000-0x0bffff: excluding 0xb0000-0xbffff pcmcia_socket pcmcia_socket1: cs: memory probe 0x0c0000-0x0cffff: excluding 0xc0000-0xcbfff pcmcia_socket pcmcia_socket1: cs: memory probe 0x0d0000-0x0dffff: clean. pcmcia_socket pcmcia_socket1: cs: memory probe 0x0e0000-0x0effff: clean. pcmcia_socket pcmcia_socket1: cs: memory probe 0x60000000-0x60ffffff: clean. pcmcia_socket pcmcia_socket1: cs: memory probe 0xa0000000-0xa0ffffff: clean. pcmcia_socket pcmcia_socket1: cs: memory probe 0x0cc000-0x0effff: excluding 0xe0000-0xeffff pcmcia_socket pcmcia_socket1: cs: unable to map card memory! If filtering out the first 1MB is reverted, everything works as expected. Tested-by: Robert Resch <fli4l@robert.reschpara.de> Signed-off-by: Christoph Schulz <develop@kristov.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-09-14KVM: x86: Inter-privilege level ret emulation is not implemenetedNadav Amit1-0/+4
commit 9e8919ae793f4edfaa29694a70f71a515ae9942a upstream. Return unhandlable error on inter-privilege level ret instruction. This is since the current emulation does not check the privilege level correctly when loading the CS, and does not pop RSP/SS as needed. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06x86_32, entry: Store badsys error code in %eaxSven Wegener1-4/+5
commit 8142b215501f8b291a108a202b3a053a265b03dd upstream. Commit 554086d ("x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)") introduced a regression in the x86_32 syscall entry code, resulting in syscall() not returning proper errors for undefined syscalls on CPUs supporting the sysenter feature. The following code: > int result = syscall(666); > printf("result=%d errno=%d error=%s\n", result, errno, strerror(errno)); results in: > result=666 errno=0 error=Success Obviously, the syscall return value is the called syscall number, but it should have been an ENOSYS error. When run under ptrace it behaves correctly, which makes it hard to debug in the wild: > result=-1 errno=38 error=Function not implemented The %eax register is the return value register. For debugging via ptrace the syscall entry code stores the complete register context on the stack. The badsys handlers only store the ENOSYS error code in the ptrace register set and do not set %eax like a regular syscall handler would. The old resume_userspace call chain contains code that clobbers %eax and it restores %eax from the ptrace registers afterwards. The same goes for the ptrace-enabled call chain. When ptrace is not used, the syscall return value is the passed-in syscall number from the untouched %eax register. Use %eax as the return value register in syscall_badsys and sysenter_badsys, like a real syscall handler does, and have the caller push the value onto the stack for ptrace access. Signed-off-by: Sven Wegener <sven.wegener@stealer.net> Link: http://lkml.kernel.org/r/alpine.LNX.2.11.1407221022380.31021@titan.int.lan.stealer.net Reviewed-and-tested-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06x86, ioremap: Speed up check for RAM pagesRoland Dreier1-7/+19
commit c81c8a1eeede61e92a15103748c23d100880cc8a upstream. In __ioremap_caller() (the guts of ioremap), we loop over the range of pfns being remapped and checks each one individually with page_is_ram(). For large ioremaps, this can be very slow. For example, we have a device with a 256 GiB PCI BAR, and ioremapping this BAR can take 20+ seconds -- sometimes long enough to trigger the soft lockup detector! Internally, page_is_ram() calls walk_system_ram_range() on a single page. Instead, we can make a single call to walk_system_ram_range() from __ioremap_caller(), and do our further checks only for any RAM pages that we find. For the common case of MMIO, this saves an enormous amount of work, since the range being ioremapped doesn't intersect system RAM at all. With this change, ioremap on our 256 GiB BAR takes less than 1 second. Signed-off-by: Roland Dreier <roland@purestorage.com> Link: http://lkml.kernel.org/r/1399054721-1331-1-git-send-email-roland@kernel.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06x86-32, espfix: Remove filter for espfix32 due to raceH. Peter Anvin1-5/+0
commit 246f2d2ee1d715e1077fc47d61c394569c8ee692 upstream. It is not safe to use LAR to filter when to go down the espfix path, because the LDT is per-process (rather than per-thread) and another thread might change the descriptors behind our back. Fortunately it is always *safe* (if a bit slow) to go down the espfix path, and a 32-bit LDT stack segment is extremely rare. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/1398816946-3351-1-git-send-email-hpa@linux.intel.com Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06locking/mutex: Disable optimistic spinning on some architecturesPeter Zijlstra1-0/+1
commit 4badad352a6bb202ec68afa7a574c0bb961e5ebc upstream. The optimistic spin code assumes regular stores and cmpxchg() play nice; this is found to not be true for at least: parisc, sparc32, tile32, metag-lock1, arc-!llsc and hexagon. There is further wreckage, but this in particular seemed easy to trigger, so blacklist this. Opt in for known good archs. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: James Bottomley <James.Bottomley@hansenpartnership.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Jason Low <jason.low2@hp.com> Cc: Waiman Long <waiman.long@hp.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: John David Anglin <dave.anglin@bell.net> Cc: James Hogan <james.hogan@imgtec.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: sparclinux@vger.kernel.org Link: http://lkml.kernel.org/r/20140606175316.GV13930@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.2: - Adjust context - Drop arm64 change] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06perf/x86/intel: ignore CondChgd bit to avoid false NMI handlingHATAYAMA Daisuke1-0/+9
commit b292d7a10487aee6e74b1c18b8d95b92f40d4a4f upstream. Currently, any NMI is falsely handled by a NMI handler of NMI watchdog if CondChgd bit in MSR_CORE_PERF_GLOBAL_STATUS MSR is set. For example, we use external NMI to make system panic to get crash dump, but in this case, the external NMI is falsely handled do to the issue. This commit deals with the issue simply by ignoring CondChgd bit. Here is explanation in detail. On x86 NMI watchdog uses performance monitoring feature to periodically signal NMI each time performance counter gets overflowed. intel_pmu_handle_irq() is called as a NMI_LOCAL handler from a NMI handler of NMI watchdog, perf_event_nmi_handler(). It identifies an owner of a given NMI by looking at overflow status bits in MSR_CORE_PERF_GLOBAL_STATUS MSR. If some of the bits are set, then it handles the given NMI as its own NMI. The problem is that the intel_pmu_handle_irq() doesn't distinguish CondChgd bit from other bits. Unlike the other status bits, CondChgd bit doesn't represent overflow status for performance counters. Thus, CondChgd bit cannot be thought of as a mark indicating a given NMI is NMI watchdog's. As a result, if CondChgd bit is set, any NMI is falsely handled by the NMI handler of NMI watchdog. Also, if type of the falsely handled NMI is either NMI_UNKNOWN, NMI_SERR or NMI_IO_CHECK, the corresponding action is never performed until CondChgd bit is cleared. I noticed this behavior on systems with Ivy Bridge processors: Intel Xeon CPU E5-2630 v2 and Intel Xeon CPU E7-8890 v2. On both systems, CondChgd bit in MSR_CORE_PERF_GLOBAL_STATUS MSR has already been set in the beginning at boot. Then the CondChgd bit is immediately cleared by next wrmsr to MSR_CORE_PERF_GLOBAL_CTRL MSR and appears to remain 0. On the other hand, on older processors such as Nehalem, Xeon E7540, CondChgd bit is not set in the beginning at boot. I'm not sure about exact behavior of CondChgd bit, in particular when this bit is set. Although I read Intel System Programmer's Manual to figure out that, the descriptions I found are: In 18.9.1: "The MSR_PERF_GLOBAL_STATUS MSR also provides a ¡sticky bit¢ to indicate changes to the state of performancmonitoring hardware" In Table 35-2 IA-32 Architectural MSRs 63 CondChg: status bits of this register has changed. These are different from the bahviour I see on the actual system as I explained above. At least, I think ignoring CondChgd bit should be enough for NMI watchdog perspective. Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Acked-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20140625.103503.409316067.d.hatayama@jp.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06KVM: x86: preserve the high 32-bits of the PAT registerPaolo Bonzini1-1/+1
commit 7cb060a91c0efc5ff94f83c6df3ed705e143cdb9 upstream. KVM does not really do much with the PAT, so this went unnoticed for a long time. It is exposed however if you try to do rdmsr on the PAT register. Reported-by: Valentine Sinitsyn <valentine.sinitsyn@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-08-06KVM: x86: Increase the number of fixed MTRR regs to 10Nadav Amit1-1/+1
commit 682367c494869008eb89ef733f196e99415ae862 upstream. Recent Intel CPUs have 10 variable range MTRRs. Since operating systems sometime make assumptions on CPUs while they ignore capability MSRs, it is better for KVM to be consistent with recent CPUs. Reporting more MTRRs than actually supported has no functional implications. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-07-11ptrace,x86: force IRET path after a ptrace_stop()Tejun Heo1-0/+16
commit b9cd18de4db3c9ffa7e17b0dc0ca99ed5aa4d43a upstream. The 'sysret' fastpath does not correctly restore even all regular registers, much less any segment registers or reflags values. That is very much part of why it's faster than 'iret'. Normally that isn't a problem, because the normal ptrace() interface catches the process using the signal handler infrastructure, which always returns with an iret. However, some paths can get caught using ptrace_event() instead of the signal path, and for those we need to make sure that we aren't going to return to user space using 'sysret'. Otherwise the modifications that may have been done to the register set by the tracer wouldn't necessarily take effect. Fix it by forcing IRET path by setting TIF_NOTIFY_RESUME from arch_ptrace_stop_needed() which is invoked from ptrace_stop(). Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Oleg Nesterov <oleg@redhat.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-07-11x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)Andy Lutomirski1-2/+8
commit 554086d85e71f30abe46fc014fea31929a7c6a8a upstream. The bad syscall nr paths are their own incomprehensible route through the entry control flow. Rearrange them to work just like syscalls that return -ENOSYS. This fixes an OOPS in the audit code when fast-path auditing is enabled and sysenter gets a bad syscall nr (CVE-2014-4508). This has probably been broken since Linux 2.6.27: af0575bba0 i386 syscall audit fast-path Cc: Roland McGrath <roland@redhat.com> Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/e09c499eade6fc321266dd6b54da7beb28d6991c.1403558229.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-06-09x86-64, modify_ldt: Make support for 16-bit segments a runtime optionLinus Torvalds2-1/+11
commit fa81511bb0bbb2b1aace3695ce869da9762624ff upstream. Checkin: b3b42ac2cbae x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernels disabled 16-bit segments on 64-bit kernels due to an information leak. However, it does seem that people are genuinely using Wine to run old 16-bit Windows programs on Linux. A proper fix for this ("espfix64") is coming in the upcoming merge window, but as a temporary fix, create a sysctl to allow the administrator to re-enable support for 16-bit segments. It adds a "/proc/sys/abi/ldt16" sysctl that defaults to zero (off). If you hit this issue and care about your old Windows program more than you care about a kernel stack address information leak, you can do echo 1 > /proc/sys/abi/ldt16 as root (add it to your startup scripts), and you should be ok. The sysctl table is only added if you have COMPAT support enabled on x86-64, but I assume anybody who runs old windows binaries very much does that ;) Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/r/CA%2B55aFw9BPoD10U1LfHbOMpHWZkvJTkMcfCs9s3urPr1YyWBxw@mail.gmail.com Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-06-09x86, mm, hugetlb: Add missing TLB page invalidation for hugetlb_cow()Anthony Iliopoulos1-0/+1
commit 9844f5462392b53824e8b86726e7c33b5ecbb676 upstream. The invalidation is required in order to maintain proper semantics under CoW conditions. In scenarios where a process clones several threads, a thread operating on a core whose DTLB entry for a particular hugepage has not been invalidated, will be reading from the hugepage that belongs to the forked child process, even after hugetlb_cow(). The thread will not see the updated page as long as the stale DTLB entry remains cached, the thread attempts to write into the page, the child process exits, or the thread gets migrated to a different processor. Signed-off-by: Anthony Iliopoulos <anthony.iliopoulos@huawei.com> Link: http://lkml.kernel.org/r/20140514092948.GA17391@server-36.huawei.corp Suggested-by: Shay Goikhman <shay.goikhman@huawei.com> Acked-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-30x86-64, modify_ldt: Ban 16-bit segments on 64-bit kernelsH. Peter Anvin1-0/+11
commit b3b42ac2cbae1f3cecbb6229964a4d48af31d382 upstream. The IRET instruction, when returning to a 16-bit segment, only restores the bottom 16 bits of the user space stack pointer. We have a software workaround for that ("espfix") for the 32-bit kernel, but it relies on a nonzero stack segment base which is not available in 32-bit mode. Since 16-bit support is somewhat crippled anyway on a 64-bit kernel (no V86 mode), and most (if not quite all) 64-bit processors support virtualization for the users who really need it, simply reject attempts at creating a 16-bit segment when running on top of a 64-bit kernel. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Link: http://lkml.kernel.org/n/tip-kicdm89kzw9lldryb1br9od0@git.kernel.org Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-30x86, hyperv: Bypass the timer_irq_works() checkJason Wang1-0/+6
commit ca3ba2a2f4a49a308e7d78c784d51b2332064f15 upstream. This patch bypass the timer_irq_works() check for hyperv guest since: - It was guaranteed to work. - timer_irq_works() may fail sometime due to the lpj calibration were inaccurate in a hyperv guest or a buggy host. In the future, we should get the tsc frequency from hypervisor and use preset lpj instead. [ hpa: I would prefer to not defer things to "the future" in the future... ] Cc: K. Y. Srinivasan <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Acked-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Link: http://lkml.kernel.org/r/1393558229-14755-1-git-send-email-jasowang@redhat.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-09KVM: VMX: fix use after free of vmx->loaded_vmcsMarcelo Tosatti1-1/+1
commit 26a865f4aa8e66a6d94958de7656f7f1b03c6c56 upstream. After free_loaded_vmcs executes, the "loaded_vmcs" structure is kfreed, and now vmx->loaded_vmcs points to a kfreed area. Subsequent free_loaded_vmcs then attempts to manipulate vmx->loaded_vmcs. Switch the order to avoid the problem. https://bugzilla.redhat.com/show_bug.cgi?id=1047892 Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-09KVM: MMU: handle invalid root_hpa at __direct_mapMarcelo Tosatti1-0/+3
commit 989c6b34f6a9480e397b170cc62237e89bf4fdb9 upstream. It is possible for __direct_map to be called on invalid root_hpa (-1), two examples: 1) try_async_pf -> can_do_async_pf -> vmx_interrupt_allowed -> nested_vmx_vmexit 2) vmx_handle_exit -> vmx_interrupt_allowed -> nested_vmx_vmexit Then to load_vmcs12_host_state and kvm_mmu_reset_context. Check for this possibility, let fault exception be regenerated. BZ: https://bugzilla.redhat.com/show_bug.cgi?id=924916 Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-02x86/amd/numa: Fix northbridge quirk to assign correct NUMA nodeDaniel J Blueman1-1/+1
commit 847d7970defb45540735b3fb4e88471c27cacd85 upstream. For systems with multiple servers and routed fabric, all northbridges get assigned to the first server. Fix this by also using the node reported from the PCI bus. For single-fabric systems, the northbriges are on PCI bus 0 by definition, which are on NUMA node 0 by definition, so this is invarient on most systems. Tested on fam10h and fam15h single and multi-fabric systems and candidate for stable. Signed-off-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Steffen Persvold <sp@numascale.com> Acked-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/1394710981-3596-1-git-send-email-daniel@numascale.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-02KVM: SVM: fix cr8 intercept windowRadim Krčmář1-3/+3
commit 596f3142d2b7be307a1652d59e7b93adab918437 upstream. We always disable cr8 intercept in its handler, but only re-enable it if handling KVM_REQ_EVENT, so there can be a window where we do not intercept cr8 writes, which allows an interrupt to disrupt a higher priority task. Fix this by disabling intercepts in the same function that re-enables them when needed. This fixes BSOD in Windows 2008. Signed-off-by: Radim Krčmář <rkrcmar@redhat.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-02perf/x86: Fix event schedulingPeter Zijlstra1-0/+3
commit 26e61e8939b1fe8729572dabe9a9e97d930dd4f6 upstream. Vince "Super Tester" Weaver reported a new round of syscall fuzzing (Trinity) failures, with perf WARN_ON()s triggering. He also provided traces of the failures. This is I think the relevant bit: > pec_1076_warn-2804 [000] d... 147.926153: x86_pmu_disable: x86_pmu_disable > pec_1076_warn-2804 [000] d... 147.926153: x86_pmu_state: Events: { > pec_1076_warn-2804 [000] d... 147.926156: x86_pmu_state: 0: state: .R config: ffffffffffffffff ( (null)) > pec_1076_warn-2804 [000] d... 147.926158: x86_pmu_state: 33: state: AR config: 0 (ffff88011ac99800) > pec_1076_warn-2804 [000] d... 147.926159: x86_pmu_state: } > pec_1076_warn-2804 [000] d... 147.926160: x86_pmu_state: n_events: 1, n_added: 0, n_txn: 1 > pec_1076_warn-2804 [000] d... 147.926161: x86_pmu_state: Assignment: { > pec_1076_warn-2804 [000] d... 147.926162: x86_pmu_state: 0->33 tag: 1 config: 0 (ffff88011ac99800) > pec_1076_warn-2804 [000] d... 147.926163: x86_pmu_state: } > pec_1076_warn-2804 [000] d... 147.926166: collect_events: Adding event: 1 (ffff880119ec8800) So we add the insn:p event (fd[23]). At this point we should have: n_events = 2, n_added = 1, n_txn = 1 > pec_1076_warn-2804 [000] d... 147.926170: collect_events: Adding event: 0 (ffff8800c9e01800) > pec_1076_warn-2804 [000] d... 147.926172: collect_events: Adding event: 4 (ffff8800cbab2c00) We try and add the {BP,cycles,br_insn} group (fd[3], fd[4], fd[15]). These events are 0:cycles and 4:br_insn, the BP event isn't x86_pmu so that's not visible. group_sched_in() pmu->start_txn() /* nop - BP pmu */ event_sched_in() event->pmu->add() So here we should end up with: 0: n_events = 3, n_added = 2, n_txn = 2 4: n_events = 4, n_added = 3, n_txn = 3 But seeing the below state on x86_pmu_enable(), the must have failed, because the 0 and 4 events aren't there anymore. Looking at group_sched_in(), since the BP is the leader, its event_sched_in() must have succeeded, for otherwise we would not have seen the sibling adds. But since neither 0 or 4 are in the below state; their event_sched_in() must have failed; but I don't see why, the complete state: 0,0,1:p,4 fits perfectly fine on a core2. However, since we try and schedule 4 it means the 0 event must have succeeded! Therefore the 4 event must have failed, its failure will have put group_sched_in() into the fail path, which will call: event_sched_out() event->pmu->del() on 0 and the BP event. Now x86_pmu_del() will reduce n_events; but it will not reduce n_added; giving what we see below: n_event = 2, n_added = 2, n_txn = 2 > pec_1076_warn-2804 [000] d... 147.926177: x86_pmu_enable: x86_pmu_enable > pec_1076_warn-2804 [000] d... 147.926177: x86_pmu_state: Events: { > pec_1076_warn-2804 [000] d... 147.926179: x86_pmu_state: 0: state: .R config: ffffffffffffffff ( (null)) > pec_1076_warn-2804 [000] d... 147.926181: x86_pmu_state: 33: state: AR config: 0 (ffff88011ac99800) > pec_1076_warn-2804 [000] d... 147.926182: x86_pmu_state: } > pec_1076_warn-2804 [000] d... 147.926184: x86_pmu_state: n_events: 2, n_added: 2, n_txn: 2 > pec_1076_warn-2804 [000] d... 147.926184: x86_pmu_state: Assignment: { > pec_1076_warn-2804 [000] d... 147.926186: x86_pmu_state: 0->33 tag: 1 config: 0 (ffff88011ac99800) > pec_1076_warn-2804 [000] d... 147.926188: x86_pmu_state: 1->0 tag: 1 config: 1 (ffff880119ec8800) > pec_1076_warn-2804 [000] d... 147.926188: x86_pmu_state: } > pec_1076_warn-2804 [000] d... 147.926190: x86_pmu_enable: S0: hwc->idx: 33, hwc->last_cpu: 0, hwc->last_tag: 1 hwc->state: 0 So the problem is that x86_pmu_del(), when called from a group_sched_in() that fails (for whatever reason), and without x86_pmu TXN support (because the leader is !x86_pmu), will corrupt the n_added state. Reported-and-Tested-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stephane Eranian <eranian@google.com> Cc: Dave Jones <davej@redhat.com> Link: http://lkml.kernel.org/r/20140221150312.GF3104@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-02x86: Add check for number of available vectors before CPU downPrarit Bhargava3-0/+76
commit da6139e49c7cb0f4251265cb5243b8d220adb48d upstream. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=64791 When a cpu is downed on a system, the irqs on the cpu are assigned to other cpus. It is possible, however, that when a cpu is downed there aren't enough free vectors on the remaining cpus to account for the vectors from the cpu that is being downed. This results in an interesting "overflow" condition where irqs are "assigned" to a CPU but are not handled. For example, when downing cpus on a 1-64 logical processor system: <snip> [ 232.021745] smpboot: CPU 61 is now offline [ 238.480275] smpboot: CPU 62 is now offline [ 245.991080] ------------[ cut here ]------------ [ 245.996270] WARNING: CPU: 0 PID: 0 at net/sched/sch_generic.c:264 dev_watchdog+0x246/0x250() [ 246.005688] NETDEV WATCHDOG: p786p1 (ixgbe): transmit queue 0 timed out [ 246.013070] Modules linked in: lockd sunrpc iTCO_wdt iTCO_vendor_support sb_edac ixgbe microcode e1000e pcspkr joydev edac_core lpc_ich ioatdma ptp mdio mfd_core i2c_i801 dca pps_core i2c_core wmi acpi_cpufreq isci libsas scsi_transport_sas [ 246.037633] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.12.0+ #14 [ 246.044451] Hardware name: Intel Corporation S4600LH ........../SVRBD-ROW_T, BIOS SE5C600.86B.01.08.0003.022620131521 02/26/2013 [ 246.057371] 0000000000000009 ffff88081fa03d40 ffffffff8164fbf6 ffff88081fa0ee48 [ 246.065728] ffff88081fa03d90 ffff88081fa03d80 ffffffff81054ecc ffff88081fa13040 [ 246.074073] 0000000000000000 ffff88200cce0000 0000000000000040 0000000000000000 [ 246.082430] Call Trace: [ 246.085174] <IRQ> [<ffffffff8164fbf6>] dump_stack+0x46/0x58 [ 246.091633] [<ffffffff81054ecc>] warn_slowpath_common+0x8c/0xc0 [ 246.098352] [<ffffffff81054fb6>] warn_slowpath_fmt+0x46/0x50 [ 246.104786] [<ffffffff815710d6>] dev_watchdog+0x246/0x250 [ 246.110923] [<ffffffff81570e90>] ? dev_deactivate_queue.constprop.31+0x80/0x80 [ 246.119097] [<ffffffff8106092a>] call_timer_fn+0x3a/0x110 [ 246.125224] [<ffffffff8106280f>] ? update_process_times+0x6f/0x80 [ 246.132137] [<ffffffff81570e90>] ? dev_deactivate_queue.constprop.31+0x80/0x80 [ 246.140308] [<ffffffff81061db0>] run_timer_softirq+0x1f0/0x2a0 [ 246.146933] [<ffffffff81059a80>] __do_softirq+0xe0/0x220 [ 246.152976] [<ffffffff8165fedc>] call_softirq+0x1c/0x30 [ 246.158920] [<ffffffff810045f5>] do_softirq+0x55/0x90 [ 246.164670] [<ffffffff81059d35>] irq_exit+0xa5/0xb0 [ 246.170227] [<ffffffff8166062a>] smp_apic_timer_interrupt+0x4a/0x60 [ 246.177324] [<ffffffff8165f40a>] apic_timer_interrupt+0x6a/0x70 [ 246.184041] <EOI> [<ffffffff81505a1b>] ? cpuidle_enter_state+0x5b/0xe0 [ 246.191559] [<ffffffff81505a17>] ? cpuidle_enter_state+0x57/0xe0 [ 246.198374] [<ffffffff81505b5d>] cpuidle_idle_call+0xbd/0x200 [ 246.204900] [<ffffffff8100b7ae>] arch_cpu_idle+0xe/0x30 [ 246.210846] [<ffffffff810a47b0>] cpu_startup_entry+0xd0/0x250 [ 246.217371] [<ffffffff81646b47>] rest_init+0x77/0x80 [ 246.223028] [<ffffffff81d09e8e>] start_kernel+0x3ee/0x3fb [ 246.229165] [<ffffffff81d0989f>] ? repair_env_string+0x5e/0x5e [ 246.235787] [<ffffffff81d095a5>] x86_64_start_reservations+0x2a/0x2c [ 246.242990] [<ffffffff81d0969f>] x86_64_start_kernel+0xf8/0xfc [ 246.249610] ---[ end trace fb74fdef54d79039 ]--- [ 246.254807] ixgbe 0000:c2:00.0 p786p1: initiating reset due to tx timeout [ 246.262489] ixgbe 0000:c2:00.0 p786p1: Reset adapter Last login: Mon Nov 11 08:35:14 from 10.18.17.119 [root@(none) ~]# [ 246.792676] ixgbe 0000:c2:00.0 p786p1: detected SFP+: 5 [ 249.231598] ixgbe 0000:c2:00.0 p786p1: NIC Link is Up 10 Gbps, Flow Control: RX/TX [ 246.792676] ixgbe 0000:c2:00.0 p786p1: detected SFP+: 5 [ 249.231598] ixgbe 0000:c2:00.0 p786p1: NIC Link is Up 10 Gbps, Flow Control: RX/TX (last lines keep repeating. ixgbe driver is dead until module reload.) If the downed cpu has more vectors than are free on the remaining cpus on the system, it is possible that some vectors are "orphaned" even though they are assigned to a cpu. In this case, since the ixgbe driver had a watchdog, the watchdog fired and notified that something was wrong. This patch adds a function, check_vectors(), to compare the number of vectors on the CPU going down and compares it to the number of vectors available on the system. If there aren't enough vectors for the CPU to go down, an error is returned and propogated back to userspace. v2: Do not need to look at percpu irqs v3: Need to check affinity to prevent counting of MSIs in IOAPIC Lowest Priority Mode v4: Additional changes suggested by Gong Chen. v5/v6/v7/v8: Updated comment text Signed-off-by: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1389613861-3853-1-git-send-email-prarit@redhat.com Reviewed-by: Gong Chen <gong.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Michel Lespinasse <walken@google.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Yang Zhang <yang.z.zhang@Intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Janet Morgan <janet.morgan@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Ruiv Wang <ruiv.wang@gmail.com> Cc: Gong Chen <gong.chen@linux.intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-02KVM: x86: limit PIT timer frequencyMarcelo Tosatti4-3/+23
commit 9ed96e87c5748de4c2807ef17e81287c7304186c upstream. Limit PIT timer frequency similarly to the limit applied by LAPIC timer. Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 3.2: - Adjust context - s/ps->period/pt->period/] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-04-02x86/efi: Fix off-by-one bug in EFI Boot Services reservationDave Young1-1/+1
commit a7f84f03f660d93574ac88835d056c0d6468aebe upstream. Current code check boot service region with kernel text region by: start+size >= __pa_symbol(_text) The end of the above region should be start + size - 1 instead. I see this problem in ovmf + Fedora 19 grub boot: text start: 1000000 md start: 800000 md size: 800000 Signed-off-by: Dave Young <dyoung@redhat.com> Acked-by: Borislav Petkov <bp@suse.de> Acked-by: Toshi Kani <toshi.kani@hp.com> Tested-by: Toshi Kani <toshi.kani@hp.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> [bwh: Backported to 3.2: s/__pa_symbol/virt_to_phys/] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-02-15perf/x86/amd/ibs: Fix waking up from S3 for AMD family 10hRobert Richter1-8/+45
commit bee09ed91cacdbffdbcd3b05de8409c77ec9fcd6 upstream. On AMD family 10h we see following error messages while waking up from S3 for all non-boot CPUs leading to a failed IBS initialization: Enabling non-boot CPUs ... smpboot: Booting Node 0 Processor 1 APIC 0x1 [Firmware Bug]: cpu 1, try to use APIC500 (LVT offset 0) for vector 0x400, but the register is already in use for vector 0xf9 on another cpu perf: IBS APIC setup failed on cpu #1 process: Switch to broadcast mode on CPU1 CPU1 is up ... ACPI: Waking up from system sleep state S3 Reason for this is that during suspend the LVT offset for the IBS vector gets lost and needs to be reinialized while resuming. The offset is read from the IBSCTL msr. On family 10h the offset needs to be 1 as offset 0 is used for the MCE threshold interrupt, but firmware assings it for IBS to 0 too. The kernel needs to reprogram the vector. The msr is a readonly node msr, but a new value can be written via pci config space access. The reinitialization is implemented for family 10h in setup_ibs_ctl() which is forced during IBS setup. This patch fixes IBS setup after waking up from S3 by adding resume/supend hooks for the boot cpu which does the offset reinitialization. Marking it as stable to let distros pick up this fix. Signed-off-by: Robert Richter <rric@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1389797849-5565-1-git-send-email-rric.net@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-02-15x86, fpu, amd: Clear exceptions in AMD FXSAVE workaroundLinus Torvalds1-6/+7
commit 26bef1318adc1b3a530ecc807ef99346db2aa8b0 upstream. Before we do an EMMS in the AMD FXSAVE information leak workaround we need to clear any pending exceptions, otherwise we trap with a floating-point exception inside this code. Reported-by: halfdog <me@halfdog.net> Tested-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/CA%2B55aFxQnY_PCG_n4=0w-VG=YLXL-yr7oMxyy0WU2gCBAf3ydg@mail.gmail.com Signed-off-by: H. Peter Anvin <hpa@zytor.com> [bwh: Backported to 3.2: adjust filename, context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-02-15KVM: x86: Convert vapic synchronization to _cached functions (CVE-2013-6368)Andy Honig3-44/+15
commit fda4e2e85589191b123d31cdc21fd33ee70f50fd upstream. In kvm_lapic_sync_from_vapic and kvm_lapic_sync_to_vapic there is the potential to corrupt kernel memory if userspace provides an address that is at the end of a page. This patches concerts those functions to use kvm_write_guest_cached and kvm_read_guest_cached. It also checks the vapic_address specified by userspace during ioctl processing and returns an error to userspace if the address is not a valid GPA. This is generally not guest triggerable, because the required write is done by firmware that runs before the guest. Also, it only affects AMD processors and oldish Intel that do not have the FlexPriority feature (unless you disable FlexPriority, of course; then newer processors are also affected). Fixes: b93463aa59d6 ('KVM: Accelerated apic support') Reported-by: Andrew Honig <ahonig@google.com> Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [dannf: backported to Debian's 3.2] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-01-03KVM: x86: Fix potential divide by 0 in lapic (CVE-2013-6367)Andy Honig1-1/+2
commit b963a22e6d1a266a67e9eecc88134713fd54775c upstream. Under guest controllable circumstances apic_get_tmcct will execute a divide by zero and cause a crash. If the guest cpuid support tsc deadline timers and performs the following sequence of requests the host will crash. - Set the mode to periodic - Set the TMICT to 0 - Set the mode bits to 11 (neither periodic, nor one shot, nor tsc deadline) - Set the TMICT to non-zero. Then the lapic_timer.period will be 0, but the TMICT will not be. If the guest then reads from the TMCCT then the host will perform a divide by 0. This patch ensures that if the lapic_timer.period is 0, then the division does not occur. Reported-by: Andrew Honig <ahonig@google.com> Signed-off-by: Andrew Honig <ahonig@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 3.2: s/kvm_apic_get_reg/apic_get_reg/] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-01-03x86, efi: Don't use (U)EFI time services on 32 bitMatthew Garrett1-5/+0
commit 04bf9ba720fcc4fa313fa122b799ae0989b6cd50 upstream. UEFI time services are often broken once we're in virtual mode. We were already refusing to use them on 64-bit systems, but it turns out that they're also broken on some 32-bit firmware, including the Dell Venue. Disable them for now, we can revisit once we have the 1:1 mappings code incorporated. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Link: http://lkml.kernel.org/r/1385754283-2464-1-git-send-email-matthew.garrett@nebula.com Cc: Matt Fleming <matt.fleming@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> [bwh: Backported to 3.2: deleted code is slightly different] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-01-03x86, build: Pass in additional -mno-mmx, -mno-sse optionsH. Peter Anvin2-3/+4
commit 8b3b005d675726e38bc504d2e35a991e55819155 upstream. In checkin 5551a34e5aea x86-64, build: Always pass in -mno-sse we unconditionally added -mno-sse to the main build, to keep newer compilers from generating SSE instructions from autovectorization. However, this did not extend to the special environments (arch/x86/boot, arch/x86/boot/compressed, and arch/x86/realmode/rm). Add -mno-sse to the compiler command line for these environments, and add -mno-mmx to all the environments as well, as we don't want a compiler to generate MMX code either. This patch also removes a $(cc-option) call for -m32, since we have long since stopped supporting compilers too old for the -m32 option, and in fact hardcode it in other places in the Makefiles. Reported-by: Kevin B. Smith <kevin.b.smith@intel.com> Cc: Sunil K. Pandey <sunil.k.pandey@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Cc: H. J. Lu <hjl.tools@gmail.com> Link: http://lkml.kernel.org/n/tip-j21wzqv790q834n7yc6g80j1@git.kernel.org [bwh: Backported to 3.2: - Drop changes to arch/x86/Makefile, which sets these flags earlier - Adjust context - Drop changes to arch/x86/realmode/rm/Makefile which doesn't exist] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-01-03x86/microcode/amd: Tone down printk(), don't treat a missing firmware file ↵Thomas Renninger1-1/+1
as an error commit 11f918d3e2d3861b6931e97b3aa778e4984935aa upstream. Do it the same way as done in microcode_intel.c: use pr_debug() for missing firmware files. There seem to be CPUs out there for which no microcode update has been submitted to kernel-firmware repo yet resulting in scary sounding error messages in dmesg: microcode: failed to load file amd-ucode/microcode_amd_fam16h.bin Signed-off-by: Thomas Renninger <trenn@suse.de> Acked-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/1384274383-43510-1-git-send-email-trenn@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2014-01-03x86/apic: Disable I/O APIC before shutdown of the local APICFenghua Yu2-5/+8
commit 522e66464467543c0d88d023336eec4df03ad40b upstream. In reboot and crash path, when we shut down the local APIC, the I/O APIC is still active. This may cause issues because external interrupts can still come in and disturb the local APIC during shutdown process. To quiet external interrupts, disable I/O APIC before shutdown local APIC. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/1382578212-4677-1-git-send-email-fenghua.yu@intel.com [ I suppose the 'issue' is a hang during shutdown. It's a fine change nevertheless. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-11-28compiler/gcc4: Add quirk for 'asm goto' miscompilation bugIngo Molnar2-2/+2
commit 3f0116c3238a96bc18ad4b4acefe4e7be32fa861 upstream. Fengguang Wu, Oleg Nesterov and Peter Zijlstra tracked down a kernel crash to a GCC bug: GCC miscompiles certain 'asm goto' constructs, as outlined here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 Implement a workaround suggested by Jakub Jelinek. Reported-and-tested-by: Fengguang Wu <fengguang.wu@intel.com> Reported-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Suggested-by: Jakub Jelinek <jakub@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.2: - Drop inapplicable changes - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-10-27x86/reboot: Add quirk to make Dell C6100 use reboot=pci automaticallyMasoud Sharbiani1-0/+16
commit 4f0acd31c31f03ba42494c8baf6c0465150e2621 upstream. Dell PowerEdge C6100 machines fail to completely reboot about 20% of the time. Signed-off-by: Masoud Sharbiani <msharbiani@twitter.com> Signed-off-by: Vinson Lee <vlee@twitter.com> Cc: Robin Holt <holt@sgi.com> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Link: http://lkml.kernel.org/r/1379717947-18042-1-git-send-email-vlee@freedesktop.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-10-27x86, efi: Don't map Boot Services on i386Josh Boyer1-4/+7
commit 700870119f49084da004ab588ea2b799689efaf7 upstream. Add patch to fix 32bit EFI service mapping (rhbz 726701) Multiple people are reporting hitting the following WARNING on i386, WARNING: at arch/x86/mm/ioremap.c:102 __ioremap_caller+0x3d3/0x440() Modules linked in: Pid: 0, comm: swapper Not tainted 3.9.0-rc7+ #95 Call Trace: [<c102b6af>] warn_slowpath_common+0x5f/0x80 [<c1023fb3>] ? __ioremap_caller+0x3d3/0x440 [<c1023fb3>] ? __ioremap_caller+0x3d3/0x440 [<c102b6ed>] warn_slowpath_null+0x1d/0x20 [<c1023fb3>] __ioremap_caller+0x3d3/0x440 [<c106007b>] ? get_usage_chars+0xfb/0x110 [<c102d937>] ? vprintk_emit+0x147/0x480 [<c1418593>] ? efi_enter_virtual_mode+0x1e4/0x3de [<c102406a>] ioremap_cache+0x1a/0x20 [<c1418593>] ? efi_enter_virtual_mode+0x1e4/0x3de [<c1418593>] efi_enter_virtual_mode+0x1e4/0x3de [<c1407984>] start_kernel+0x286/0x2f4 [<c1407535>] ? repair_env_string+0x51/0x51 [<c1407362>] i386_start_kernel+0x12c/0x12f Due to the workaround described in commit 916f676f8 ("x86, efi: Retain boot service code until after switching to virtual mode") EFI Boot Service regions are mapped for a period during boot. Unfortunately, with the limited size of the i386 direct kernel map it's possible that some of the Boot Service regions will not be directly accessible, which causes them to be ioremap()'d, triggering the above warning as the regions are marked as E820_RAM in the e820 memmap. There are currently only two situations where we need to map EFI Boot Service regions, 1. To workaround the firmware bug described in 916f676f8 2. To access the ACPI BGRT image but since we haven't seen an i386 implementation that requires either, this simple fix should suffice for now. [ Added to changelog - Matt ] Reported-by: Bryan O'Donoghue <bryan.odonoghue.lkml@nexus-software.ie> Acked-by: Tom Zanussi <tom.zanussi@intel.com> Acked-by: Darren Hart <dvhart@linux.intel.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Josh Boyer <jwboyer@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-09-10x86/xen: do not identity map UNUSABLE regions in the machine E820David Vrabel1-0/+22
commit 3bc38cbceb85881a8eb789ee1aa56678038b1909 upstream. If there are UNUSABLE regions in the machine memory map, dom0 will attempt to map them 1:1 which is not permitted by Xen and the kernel will crash. There isn't anything interesting in the UNUSABLE region that the dom0 kernel needs access to so we can avoid making the 1:1 mapping and treat it as RAM. We only do this for dom0, as that is where tboot case shows up. A PV domU could have an UNUSABLE region in its pseudo-physical map and would need to be handled in another patch. This fixes a boot failure on hosts with tboot. tboot marks a region in the e820 map as unusable and the dom0 kernel would attempt to map this region and Xen does not permit unusable regions to be mapped by guests. (XEN) 0000000000000000 - 0000000000060000 (usable) (XEN) 0000000000060000 - 0000000000068000 (reserved) (XEN) 0000000000068000 - 000000000009e000 (usable) (XEN) 0000000000100000 - 0000000000800000 (usable) (XEN) 0000000000800000 - 0000000000972000 (unusable) tboot marked this region as unusable. (XEN) 0000000000972000 - 00000000cf200000 (usable) (XEN) 00000000cf200000 - 00000000cf38f000 (reserved) (XEN) 00000000cf38f000 - 00000000cf3ce000 (ACPI data) (XEN) 00000000cf3ce000 - 00000000d0000000 (reserved) (XEN) 00000000e0000000 - 00000000f0000000 (reserved) (XEN) 00000000fe000000 - 0000000100000000 (reserved) (XEN) 0000000100000000 - 0000000630000000 (usable) Signed-off-by: David Vrabel <david.vrabel@citrix.com> [v1: Altered the patch and description with domU's with UNUSABLE regions] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-09-10x86 get_unmapped_area: Access mmap_legacy_base through mm_struct memberRadu Caragea2-3/+5
commit 41aacc1eea645c99edbe8fbcf78a97dc9b862adc upstream. This is the updated version of df54d6fa5427 ("x86 get_unmapped_area(): use proper mmap base for bottom-up direction") that only randomizes the mmap base address once. Signed-off-by: Radu Caragea <sinaelgl@gmail.com> Reported-and-tested-by: Jeff Shorey <shoreyjeff@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Adrian Sendroiu <molecula2788@gmail.com> Cc: Greg KH <greg@kroah.com> Cc: Kamal Mostafa <kamal@canonical.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-09-10x86, fpu: correct the asm constraints for fxsave, unbreak mxcsr.dazH.J. Lu1-1/+1
commit eaa5a990191d204ba0f9d35dbe5505ec2cdd1460 upstream. GCC will optimize mxcsr_feature_mask_init in arch/x86/kernel/i387.c: memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct)); asm volatile("fxsave %0" : : "m" (fx_scratch)); mask = fx_scratch.mxcsr_mask; if (mask == 0) mask = 0x0000ffbf; to memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct)); asm volatile("fxsave %0" : : "m" (fx_scratch)); mask = 0x0000ffbf; since asm statement doesn’t say it will update fx_scratch. As the result, the DAZ bit will be cleared. This patch fixes it. This bug dates back to at least kernel 2.6.12. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-07-27xen/time: remove blocked time accounting from xen "clockchip"Laszlo Ersek1-15/+2
commit 0b0c002c340e78173789f8afaa508070d838cf3d upstream. ... because the "clock_event_device framework" already accounts for idle time through the "event_handler" function pointer in xen_timer_interrupt(). The patch is intended as the completion of [1]. It should fix the double idle times seen in PV guests' /proc/stat [2]. It should be orthogonal to stolen time accounting (the removed code seems to be isolated). The approach may be completely misguided. [1] https://lkml.org/lkml/2011/10/6/10 [2] http://lists.xensource.com/archives/html/xen-devel/2010-08/msg01068.html John took the time to retest this patch on top of v3.10 and reported: "idle time is correctly incremented for pv and hvm for the normal case, nohz=off and nohz=idle." so lets put this patch in. Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: John Haxby <john.haxby@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-06-29x86/efi: Fix dummy variable buffer allocationBen Hutchings1-1/+6
commit b8cb62f82103083a6e8fa5470bfe634a2c06514d upstream. 1. Check for allocation failure 2. Clear the buffer contents, as they may actually be written to flash 3. Don't leak the buffer Compile-tested only. [ Tested successfully on my buggy ASUS machine - Matt ] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-06-29Modify UEFI anti-bricking codeMatthew Garrett1-9/+66
commit f8b8404337de4e2466e2e1139ea68b1f8295974f upstream. This patch reworks the UEFI anti-bricking code, including an effective reversion of cc5a080c and 31ff2f20. It turns out that calling QueryVariableInfo() from boot services results in some firmware implementations jumping to physical addresses even after entering virtual mode, so until we have 1:1 mappings for UEFI runtime space this isn't going to work so well. Reverting these gets us back to the situation where we'd refuse to create variables on some systems because they classify deleted variables as "used" until the firmware triggers a garbage collection run, which they won't do until they reach a lower threshold. This results in it being impossible to install a bootloader, which is unhelpful. Feedback from Samsung indicates that the firmware doesn't need more than 5KB of storage space for its own purposes, so that seems like a reasonable threshold. However, there's still no guarantee that a platform will attempt garbage collection merely because it drops below this threshold. It seems that this is often only triggered if an attempt to write generates a genuine EFI_OUT_OF_RESOURCES error. We can force that by attempting to create a variable larger than the remaining space. This should fail, but if it somehow succeeds we can then immediately delete it. I've tested this on the UEFI machines I have available, but I don't have a Samsung and so can't verify that it avoids the bricking problem. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Lee, Chun-Y <jlee@suse.com> [ dummy variable cleanup ] Signed-off-by: Matt Fleming <matt.fleming@intel.com> [bwh: Backported to 3.2: the reverted changes were never applied here] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-06-29x86: fix build error and kconfig for ia32_emulation and binfmtRandy Dunlap1-0/+1
commit d1603990ea626668c78527376d9ec084d634202d upstream. Fix kconfig warning and build errors on x86_64 by selecting BINFMT_ELF when COMPAT_BINFMT_ELF is being selected. warning: (IA32_EMULATION) selects COMPAT_BINFMT_ELF which has unmet direct dependencies (COMPAT && BINFMT_ELF) fs/built-in.o: In function `elf_core_dump': compat_binfmt_elf.c:(.text+0x3e093): undefined reference to `elf_core_extra_phdrs' compat_binfmt_elf.c:(.text+0x3ebcd): undefined reference to `elf_core_extra_data_size' compat_binfmt_elf.c:(.text+0x3eddd): undefined reference to `elf_core_write_extra_phdrs' compat_binfmt_elf.c:(.text+0x3f004): undefined reference to `elf_core_write_extra_data' [ hpa: This was sent to me for -next but it is a low risk build fix ] Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: http://lkml.kernel.org/r/51C0B614.5000708@infradead.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-06-29KVM: x86: remove vcpu's CPL check in host-invoked XCR setZhanghaoyu (A)1-3/+2
commit 764bcbc5a6d7a2f3e75c9f0e4caa984e2926e346 upstream. __kvm_set_xcr function does the CPL check when set xcr. __kvm_set_xcr is called in two flows, one is invoked by guest, call stack shown as below, handle_xsetbv(or xsetbv_interception) kvm_set_xcr __kvm_set_xcr the other one is invoked by host, for example during system reset: kvm_arch_vcpu_ioctl kvm_vcpu_ioctl_x86_set_xcrs __kvm_set_xcr The former does need the CPL check, but the latter does not. Signed-off-by: Zhang Haoyu <haoyu.zhang@huawei.com> [Tweaks to commit message. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
2013-06-19x86: Fix typo in kexec register clearingKees Cook1-1/+1
commit c8a22d19dd238ede87aa0ac4f7dbea8da039b9c1 upstream. Fixes a typo in register clearing code. Thanks to PaX Team for fixing this originally, and James Troup for pointing it out. Signed-off-by: Kees Cook <keescook@chromium.org> Link: http://lkml.kernel.org/r/20130605184718.GA8396@www.outflux.net Cc: PaX Team <pageexec@freemail.hu> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>