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2018-01-12x86/retpoline/crypto: Convert crypto assembler indirect jumpsDavid Woodhouse
Convert all indirect jumps in crypto assembler code to use non-speculative sequences when CONFIG_RETPOLINE is enabled. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/1515707194-20531-6-git-send-email-dwmw@amazon.co.uk
2018-01-12x86/spectre: Add boot time option to select Spectre v2 mitigationDavid Woodhouse
Add a spectre_v2= option to select the mitigation used for the indirect branch speculation vulnerability. Currently, the only option available is retpoline, in its various forms. This will be expanded to cover the new IBRS/IBPB microcode features. The RETPOLINE_AMD feature relies on a serializing LFENCE for speculation control. For AMD hardware, only set RETPOLINE_AMD if LFENCE is a serializing instruction, which is indicated by the LFENCE_RDTSC feature. [ tglx: Folded back the LFENCE/AMD fixes and reworked it so IBRS integration becomes simple ] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/1515707194-20531-5-git-send-email-dwmw@amazon.co.uk
2018-01-12x86/retpoline: Add initial retpoline supportDavid Woodhouse
Enable the use of -mindirect-branch=thunk-extern in newer GCC, and provide the corresponding thunks. Provide assembler macros for invoking the thunks in the same way that GCC does, from native and inline assembler. This adds X86_FEATURE_RETPOLINE and sets it by default on all CPUs. In some circumstances, IBRS microcode features may be used instead, and the retpoline can be disabled. On AMD CPUs if lfence is serialising, the retpoline can be dramatically simplified to a simple "lfence; jmp *\reg". A future patch, after it has been verified that lfence really is serialising in all circumstances, can enable this by setting the X86_FEATURE_RETPOLINE_AMD feature bit in addition to X86_FEATURE_RETPOLINE. Do not align the retpoline in the altinstr section, because there is no guarantee that it stays aligned when it's copied over the oldinstr during alternative patching. [ Andi Kleen: Rename the macros, add CONFIG_RETPOLINE option, export thunks] [ tglx: Put actual function CALL/JMP in front of the macros, convert to symbolic labels ] [ dwmw2: Convert back to numeric labels, merge objtool fixes ] Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/1515707194-20531-4-git-send-email-dwmw@amazon.co.uk
2018-01-12objtool: Allow alternatives to be ignoredJosh Poimboeuf
Getting objtool to understand retpolines is going to be a bit of a challenge. For now, take advantage of the fact that retpolines are patched in with alternatives. Just read the original (sane) non-alternative instruction, and ignore the patched-in retpoline. This allows objtool to understand the control flow *around* the retpoline, even if it can't yet follow what's inside. This means the ORC unwinder will fail to unwind from inside a retpoline, but will work fine otherwise. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/1515707194-20531-3-git-send-email-dwmw@amazon.co.uk
2018-01-12objtool: Detect jumps to retpoline thunksJosh Poimboeuf
A direct jump to a retpoline thunk is really an indirect jump in disguise. Change the objtool instruction type accordingly. Objtool needs to know where indirect branches are so it can detect switch statement jump tables. This fixes a bunch of warnings with CONFIG_RETPOLINE like: arch/x86/events/intel/uncore_nhmex.o: warning: objtool: nhmex_rbox_msr_enable_event()+0x44: sibling call from callable instruction with modified stack frame kernel/signal.o: warning: objtool: copy_siginfo_to_user()+0x91: sibling call from callable instruction with modified stack frame ... Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: gnomes@lxorguk.ukuu.org.uk Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: thomas.lendacky@amd.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kees Cook <keescook@google.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/1515707194-20531-2-git-send-email-dwmw@amazon.co.uk
2018-01-11x86/pti: Make unpoison of pgd for trusted boot work for realDave Hansen
The inital fix for trusted boot and PTI potentially misses the pgd clearing if pud_alloc() sets a PGD. It probably works in *practice* because for two adjacent calls to map_tboot_page() that share a PGD entry, the first will clear NX, *then* allocate and set the PGD (without NX clear). The second call will *not* allocate but will clear the NX bit. Defer the NX clearing to a point after it is known that all top-level allocations have occurred. Add a comment to clarify why. [ tglx: Massaged changelog ] Fixes: 262b6b30087 ("x86/tboot: Unbreak tboot with PTI enabled") Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Jon Masters <jcm@redhat.com> Cc: "Tim Chen" <tim.c.chen@linux.intel.com> Cc: gnomes@lxorguk.ukuu.org.uk Cc: peterz@infradead.org Cc: ning.sun@intel.com Cc: tboot-devel@lists.sourceforge.net Cc: andi@firstfloor.org Cc: luto@kernel.org Cc: law@redhat.com Cc: pbonzini@redhat.com Cc: torvalds@linux-foundation.org Cc: gregkh@linux-foundation.org Cc: dwmw@amazon.co.uk Cc: nickc@redhat.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180110224939.2695CD47@viggo.jf.intel.com
2018-01-11x86/PCI: Move and shrink AMD 64-bit window to avoid conflict=?UTF-8?q?Christian=20K=C3=B6nig?=
Avoid problems with BIOS implementations which don't report all used resources to the OS by only allocating a 256GB window directly below the hardware limit (from the BKDG, sec 2.4.6). Fixes a silent reboot loop reported by Aaro Koskinen <aaro.koskinen@iki.fi> on an AMD-based MSI MS-7699/760GA-P43(FX) system. This was apparently caused by RAM or other unreported hardware that conflicted with the new window. Link: https://support.amd.com/TechDocs/49125_15h_Models_30h-3Fh_BKDG.pdf Link: https://lkml.kernel.org/r/20180105220412.fzpwqe4zljdawr36@darkstar.musicnaut.iki.fi Fixes: fa564ad96366 ("x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models 00-1f, 30-3f, 60-7f)") Reported-by: Aaro Koskinen <aaro.koskinen@iki.fi> Signed-off-by: Christian König <christian.koenig@amd.com> [bhelgaas: changelog, comment, Fixes:] Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
2018-01-11Documentation: usb: fix typo in UVC gadgetfs config commandBin Liu
This seems to be a copy&paste error. With the fix the uvc gadget now can be created by following the instrucitons. Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-11usb: misc: usb3503: make sure reset is low for at least 100usStefan Agner
When using a GPIO which is high by default, and initialize the driver in USB Hub mode, initialization fails with: [ 111.757794] usb3503 0-0008: SP_ILOCK failed (-5) The reason seems to be that the chip is not properly reset. Probe does initialize reset low, however some lines later the code already set it back high, which is not long enouth. Make sure reset is asserted for at least 100us by inserting a delay after initializing the reset pin during probe. Signed-off-by: Stefan Agner <stefan@agner.ch> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-01-11x86/PCI: Add "pci=big_root_window" option for AMD 64-bit windows=?UTF-8?q?Christian=20K=C3=B6nig?=
Only try to enable a 64-bit window on AMD CPUs when "pci=big_root_window" is specified. This taints the kernel because the new 64-bit window uses address space we don't know anything about, and it may contain unreported devices or memory that would conflict with the window. The pci_amd_enable_64bit_bar() quirk that enables the window is specific to AMD CPUs. The generic solution would be to have the firmware enable the window and describe it in the host bridge's _CRS method, or at least describe it in the _PRS method so the OS would have the option of enabling it. Signed-off-by: Christian König <christian.koenig@amd.com> [bhelgaas: changelog, extend doc, mention taint in dmesg] Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
2018-01-11Merge branch 'kvm-insert-lfence' into kvm-masterPaolo Bonzini
Topic branch for CVE-2017-5753, avoiding conflicts in the next merge window.
2018-01-11KVM: x86: Add memory barrier on vmcs field lookupAndrew Honig
This adds a memory barrier when performing a lookup into the vmcs_field_to_offset_table. This is related to CVE-2017-5753. Signed-off-by: Andrew Honig <ahonig@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-01-11Merge tag 'usb-serial-4.15-rc8' of ↵Greg Kroah-Hartman
https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-linus Johan writes: USB-serial fixes for v4.15-rc8 Here are a couple of new device ids for cp210x. Both have been in linux-next with no reported issues. Signed-off-by: Johan Hovold <johan@kernel.org>
2018-01-11KVM: x86: emulate #UD while in guest modePaolo Bonzini
This reverts commits ae1f57670703656cc9f293722c3b8b6782f8ab3f and ac9b305caa0df6f5b75d294e4b86c1027648991e. If the hardware doesn't support MOVBE, but L0 sets CPUID.01H:ECX.MOVBE in L1's emulated CPUID information, then L1 is likely to pass that CPUID bit through to L2. L2 will expect MOVBE to work, but if L1 doesn't intercept #UD, then any MOVBE instruction executed in L2 will raise #UD, and the exception will be delivered in L2. Commit ac9b305caa0df6f5b75d294e4b86c1027648991e is a better and more complete version of ae1f57670703 ("KVM: nVMX: Do not emulate #UD while in guest mode"); however, neither considers the above case. Suggested-by: Jim Mattson <jmattson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-01-11x86: kvm: propagate register_shrinker return codeArnd Bergmann
Patch "mm,vmscan: mark register_shrinker() as __must_check" is queued for 4.16 in linux-mm and adds a warning about the unchecked call to register_shrinker: arch/x86/kvm/mmu.c:5485:2: warning: ignoring return value of 'register_shrinker', declared with attribute warn_unused_result [-Wunused-result] This changes the kvm_mmu_module_init() function to fail itself when the call to register_shrinker fails. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-01-11Merge tag 'kvm-ppc-fixes-4.15-3' of ↵Paolo Bonzini
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc into kvm-master PPC KVM fixes for 4.15 Four commits here, including two that were tagged but never merged. Three of them are for the HPT resizing code; two of those fix a user-triggerable use-after-free in the host, and one that fixes stale TLB entries in the guest. The remaining commit fixes a bug causing PR KVM guests under PowerVM to fail to start.
2018-01-11KVM MMU: check pending exception before injecting APFHaozhong Zhang
For example, when two APF's for page ready happen after one exit and the first one becomes pending, the second one will result in #DF. Instead, just handle the second page fault synchronously. Reported-by: Ross Zwisler <zwisler@gmail.com> Message-ID: <CAOxpaSUBf8QoOZQ1p4KfUp0jq76OKfGY4Uxs-Gg8ngReD99xww@mail.gmail.com> Reported-by: Alec Blayne <ab@tevsa.net> Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-01-11drm/i915: Don't adjust priority on an already signaled fenceChris Wilson
When we retire a signaled fence, we free the dependency tree. However, we skip clearing the list so that if we then try to adjust the priority of the signaled fence, we may walk the list of freed dependencies. [ 3083.156757] ================================================================== [ 3083.156806] BUG: KASAN: use-after-free in execlists_schedule+0x199/0x660 [i915] [ 3083.156810] Read of size 8 at addr ffff8806bf20f400 by task Xorg/831 [ 3083.156815] CPU: 0 PID: 831 Comm: Xorg Not tainted 4.15.0-rc6-no-psn+ #1 [ 3083.156817] Hardware name: Notebook N24_25BU/N24_25BU, BIOS 5.12 02/17/2017 [ 3083.156818] Call Trace: [ 3083.156823] dump_stack+0x5c/0x7a [ 3083.156827] print_address_description+0x6b/0x290 [ 3083.156830] kasan_report+0x28f/0x380 [ 3083.156872] ? execlists_schedule+0x199/0x660 [i915] [ 3083.156914] execlists_schedule+0x199/0x660 [i915] [ 3083.156956] ? intel_crtc_atomic_check+0x146/0x4e0 [i915] [ 3083.156997] ? execlists_submit_request+0xe0/0xe0 [i915] [ 3083.157038] ? i915_vma_misplaced.part.4+0x25/0xb0 [i915] [ 3083.157079] ? __i915_vma_do_pin+0x7c8/0xc80 [i915] [ 3083.157121] ? intel_atomic_state_alloc+0x44/0x60 [i915] [ 3083.157130] ? drm_atomic_helper_page_flip+0x3e/0xb0 [drm_kms_helper] [ 3083.157145] ? drm_mode_page_flip_ioctl+0x7d2/0x850 [drm] [ 3083.157159] ? drm_ioctl_kernel+0xa7/0xf0 [drm] [ 3083.157172] ? drm_ioctl+0x45b/0x560 [drm] [ 3083.157211] i915_gem_object_wait_priority+0x14c/0x2c0 [i915] [ 3083.157251] ? i915_gem_get_aperture_ioctl+0x150/0x150 [i915] [ 3083.157290] ? i915_vma_pin_fence+0x1d8/0x320 [i915] [ 3083.157331] ? intel_pin_and_fence_fb_obj+0x175/0x250 [i915] [ 3083.157372] ? intel_rotation_info_size+0x60/0x60 [i915] [ 3083.157413] ? intel_link_compute_m_n+0x80/0x80 [i915] [ 3083.157428] ? drm_dev_printk+0x1b0/0x1b0 [drm] [ 3083.157443] ? drm_dev_printk+0x1b0/0x1b0 [drm] [ 3083.157485] intel_prepare_plane_fb+0x2f8/0x5a0 [i915] [ 3083.157527] ? intel_crtc_get_vblank_counter+0x80/0x80 [i915] [ 3083.157536] drm_atomic_helper_prepare_planes+0xa0/0x1c0 [drm_kms_helper] [ 3083.157587] intel_atomic_commit+0x12e/0x4e0 [i915] [ 3083.157605] drm_atomic_helper_page_flip+0xa2/0xb0 [drm_kms_helper] [ 3083.157621] drm_mode_page_flip_ioctl+0x7d2/0x850 [drm] [ 3083.157638] ? drm_mode_cursor2_ioctl+0x10/0x10 [drm] [ 3083.157652] ? drm_lease_owner+0x1a/0x30 [drm] [ 3083.157668] ? drm_mode_cursor2_ioctl+0x10/0x10 [drm] [ 3083.157681] drm_ioctl_kernel+0xa7/0xf0 [drm] [ 3083.157696] drm_ioctl+0x45b/0x560 [drm] [ 3083.157711] ? drm_mode_cursor2_ioctl+0x10/0x10 [drm] [ 3083.157725] ? drm_getstats+0x20/0x20 [drm] [ 3083.157729] ? timerqueue_del+0x49/0x80 [ 3083.157732] ? __remove_hrtimer+0x62/0xb0 [ 3083.157735] ? hrtimer_try_to_cancel+0x173/0x210 [ 3083.157738] do_vfs_ioctl+0x13b/0x880 [ 3083.157741] ? ioctl_preallocate+0x140/0x140 [ 3083.157744] ? _raw_spin_unlock_irq+0xe/0x30 [ 3083.157746] ? do_setitimer+0x234/0x370 [ 3083.157750] ? SyS_setitimer+0x19e/0x1b0 [ 3083.157752] ? SyS_alarm+0x140/0x140 [ 3083.157755] ? __rcu_read_unlock+0x66/0x80 [ 3083.157757] ? __fget+0xc4/0x100 [ 3083.157760] SyS_ioctl+0x74/0x80 [ 3083.157763] entry_SYSCALL_64_fastpath+0x1a/0x7d [ 3083.157765] RIP: 0033:0x7f6135d0c6a7 [ 3083.157767] RSP: 002b:00007fff01451888 EFLAGS: 00003246 ORIG_RAX: 0000000000000010 [ 3083.157769] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f6135d0c6a7 [ 3083.157771] RDX: 00007fff01451950 RSI: 00000000c01864b0 RDI: 000000000000000c [ 3083.157772] RBP: 00007f613076f600 R08: 0000000000000001 R09: 0000000000000000 [ 3083.157773] R10: 0000000000000060 R11: 0000000000003246 R12: 0000000000000000 [ 3083.157774] R13: 0000000000000060 R14: 000000000000001b R15: 0000000000000060 [ 3083.157779] Allocated by task 831: [ 3083.157783] kmem_cache_alloc+0xc0/0x200 [ 3083.157822] i915_gem_request_await_dma_fence+0x2c4/0x5d0 [i915] [ 3083.157861] i915_gem_request_await_object+0x321/0x370 [i915] [ 3083.157900] i915_gem_do_execbuffer+0x1165/0x19c0 [i915] [ 3083.157937] i915_gem_execbuffer2+0x1ad/0x550 [i915] [ 3083.157950] drm_ioctl_kernel+0xa7/0xf0 [drm] [ 3083.157962] drm_ioctl+0x45b/0x560 [drm] [ 3083.157964] do_vfs_ioctl+0x13b/0x880 [ 3083.157966] SyS_ioctl+0x74/0x80 [ 3083.157968] entry_SYSCALL_64_fastpath+0x1a/0x7d [ 3083.157971] Freed by task 831: [ 3083.157973] kmem_cache_free+0x77/0x220 [ 3083.158012] i915_gem_request_retire+0x72c/0xa70 [i915] [ 3083.158051] i915_gem_request_alloc+0x1e9/0x8b0 [i915] [ 3083.158089] i915_gem_do_execbuffer+0xa96/0x19c0 [i915] [ 3083.158127] i915_gem_execbuffer2+0x1ad/0x550 [i915] [ 3083.158140] drm_ioctl_kernel+0xa7/0xf0 [drm] [ 3083.158153] drm_ioctl+0x45b/0x560 [drm] [ 3083.158155] do_vfs_ioctl+0x13b/0x880 [ 3083.158156] SyS_ioctl+0x74/0x80 [ 3083.158158] entry_SYSCALL_64_fastpath+0x1a/0x7d [ 3083.158162] The buggy address belongs to the object at ffff8806bf20f400 which belongs to the cache i915_dependency of size 64 [ 3083.158166] The buggy address is located 0 bytes inside of 64-byte region [ffff8806bf20f400, ffff8806bf20f440) [ 3083.158168] The buggy address belongs to the page: [ 3083.158171] page:00000000d43decc4 count:1 mapcount:0 mapping: (null) index:0x0 [ 3083.158174] flags: 0x17ffe0000000100(slab) [ 3083.158179] raw: 017ffe0000000100 0000000000000000 0000000000000000 0000000180200020 [ 3083.158182] raw: ffffea001afc16c0 0000000500000005 ffff880731b881c0 0000000000000000 [ 3083.158184] page dumped because: kasan: bad access detected [ 3083.158187] Memory state around the buggy address: [ 3083.158190] ffff8806bf20f300: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 3083.158192] ffff8806bf20f380: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 3083.158195] >ffff8806bf20f400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 3083.158196] ^ [ 3083.158199] ffff8806bf20f480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 3083.158201] ffff8806bf20f500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 3083.158203] ================================================================== Reported-by: Alexandru Chirvasitu <achirvasub@gmail.com> Reported-by: Mike Keehan <mike@keehan.net> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104436 Fixes: 1f181225f8ec ("drm/i915/execlists: Keep request->priority for its lifetime") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Alexandru Chirvasitu <achirvasub@gmail.com> Cc: Michał Winiarski <michal.winiarski@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Tested-by: Alexandru Chirvasitu <achirvasub@gmail.com> Reviewed-by: Michał Winiarski <michal.winiarski@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180106105618.13532-1-chris@chris-wilson.co.uk (cherry picked from commit c218ee03b9315073ce43992792554dafa0626eb8) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2018-01-11drm/i915: Whitelist SLICE_COMMON_ECO_CHICKEN1 on Geminilake.Kenneth Graunke
Geminilake requires the 3D driver to select whether barriers are intended for compute shaders, or tessellation control shaders, by whacking a "Barrier Mode" bit in SLICE_COMMON_ECO_CHICKEN1 when switching pipelines. Failure to do this properly can result in GPU hangs. Unfortunately, this means it needs to switch mid-batch, so only userspace can properly set it. To facilitate this, the kernel needs to whitelist the register. The workarounds page currently tags this as applying to Broxton only, but that doesn't make sense. The documentation for the register it references says the bit userspace is supposed to toggle only exists on Geminilake. Empirically, the Mesa patch to toggle this bit appears to fix intermittent GPU hangs in tessellation control shader barrier tests on Geminilake; we haven't seen those hangs on Broxton. v2: Mention WA #0862 in the comment (it doesn't have a name). Signed-off-by: Kenneth Graunke <kenneth@whitecape.org> Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180105085905.9298-1-kenneth@whitecape.org (cherry picked from commit ab062639edb0412daf6de540725276b9a5d217f9) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2018-01-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs regression fix from Al Viro/ Fix a leak in socket() introduced by commit 8e1611e23579 ("make sock_alloc_file() do sock_release() on failures"). * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Fix a leak in socket(2) when we fail to allocate a file descriptor.
2018-01-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) BPF speculation prevention and BPF_JIT_ALWAYS_ON, from Alexei Starovoitov. 2) Revert dev_get_random_name() changes as adjust the error code returns seen by userspace definitely breaks stuff. 3) Fix TX DMA map/unmap on older iwlwifi devices, from Emmanuel Grumbach. 4) From wrong AF family when requesting sock diag modules, from Andrii Vladyka. 5) Don't add new ipv6 routes attached to the null_entry, from Wei Wang. 6) Some SCTP sockopt length fixes from Marcelo Ricardo Leitner. 7) Don't leak when removing VLAN ID 0, from Cong Wang. 8) Hey there's a potential leak in ipv6_make_skb() too, from Eric Dumazet. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (27 commits) ipv6: sr: fix TLVs not being copied using setsockopt ipv6: fix possible mem leaks in ipv6_make_skb() mlxsw: spectrum_qdisc: Don't use variable array in mlxsw_sp_tclass_congestion_enable mlxsw: pci: Wait after reset before accessing HW nfp: always unmask aux interrupts at init 8021q: fix a memory leak for VLAN 0 device of_mdio: avoid MDIO bus removal when a PHY is missing caif_usb: use strlcpy() instead of strncpy() doc: clarification about setting SO_ZEROCOPY net: gianfar_ptp: move set_fipers() to spinlock protecting area sctp: make use of pre-calculated len sctp: add a ceiling to optlen in some sockopts sctp: GFP_ATOMIC is not needed in sctp_setsockopt_events bpf: introduce BPF_JIT_ALWAYS_ON config bpf: avoid false sharing of map refcount with max_entries ipv6: remove null_entry before adding default route SolutionEngine771x: add Ether TSU resource SolutionEngine771x: fix Ether platform data docs-rst: networking: wire up msg_zerocopy net: ipv4: emulate READ_ONCE() on ->hdrincl bit-field in raw_sendmsg() ...
2018-01-10Fix a leak in socket(2) when we fail to allocate a file descriptor.Al Viro
Got broken by "make sock_alloc_file() do sock_release() on failures" - cleanup after sock_map_fd() failure got pulled all the way into sock_alloc_file(), but it used to serve the case when sock_map_fd() failed *before* getting to sock_alloc_file() as well, and that got lost. Trivial to fix, fortunately. Fixes: 8e1611e23579 (make sock_alloc_file() do sock_release() on failures) Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-10ipv6: sr: fix TLVs not being copied using setsockoptMathieu Xhonneux
Function ipv6_push_rthdr4 allows to add an IPv6 Segment Routing Header to a socket through setsockopt, but the current implementation doesn't copy possible TLVs at the end of the SRH received from userspace. Therefore, the execution of the following branch if (sr_has_hmac(sr_phdr)) { ... } will never complete since the len and type fields of a possible HMAC TLV are not copied, hence seg6_get_tlv_hmac will return an error, and the HMAC will not be computed. This commit adds a memcpy in case TLVs have been appended to the SRH. Fixes: a149e7c7ce81 ("ipv6: sr: add support for SRH injection through setsockopt") Acked-by: David Lebrun <dlebrun@google.com> Signed-off-by: Mathieu Xhonneux <m.xhonneux@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10ipv6: fix possible mem leaks in ipv6_make_skb()Eric Dumazet
ip6_setup_cork() might return an error, while memory allocations have been done and must be rolled back. Fixes: 6422398c2ab0 ("ipv6: introduce ipv6_make_skb") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Reported-by: Mike Maloney <maloney@google.com> Acked-by: Mike Maloney <maloney@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10Merge branch 'mlxsw-couple-of-fixes'David S. Miller
Jiri Pirko says: ==================== mlxsw: couple of fixes Couple of small fixes for mlxsw driver. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10mlxsw: spectrum_qdisc: Don't use variable array in ↵Jiri Pirko
mlxsw_sp_tclass_congestion_enable Resolve the sparse warning: "sparse: Variable length array is used." Use 2 arrays for 2 PRM register accesses. Fixes: 96f17e0776c2 ("mlxsw: spectrum: Support RED qdisc offload") Signed-off-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Yuval Mintz <yuvalm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10mlxsw: pci: Wait after reset before accessing HWYuval Mintz
After performing reset driver polls on HW indication until learning that the reset is done, but immediately after reset the device becomes unresponsive which might lead to completion timeout on the first read. Wait for 100ms before starting the polling. Fixes: 233fa44bd67a ("mlxsw: pci: Implement reset done check") Signed-off-by: Yuval Mintz <yuvalm@mellanox.com> Reviewed-by: Ido Schimmel <idosch@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10nfp: always unmask aux interrupts at initJakub Kicinski
The link state and exception interrupts may be masked when we probe. The firmware should in theory prevent sending (and automasking) those interrupts if the device is disabled, but if my reading of the FW code is correct there are firmwares out there with race conditions in this area. The interrupt may also be masked if previous driver which used the device was malfunctioning and we didn't load the FW (there is no other good way to comprehensively reset the PF). Note that FW unmasks the data interrupts by itself when vNIC is enabled, such helpful operation is not performed for LSC/EXN interrupts. Always unmask the auxiliary interrupts after request_irq(). On the remove path add missing PCI write flush before free_irq(). Fixes: 4c3523623dc0 ("net: add driver for Netronome NFP4000/NFP6000 NIC VFs") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-108021q: fix a memory leak for VLAN 0 deviceCong Wang
A vlan device with vid 0 is allow to creat by not able to be fully cleaned up by unregister_vlan_dev() which checks for vlan_id!=0. Also, VLAN 0 is probably not a valid number and it is kinda "reserved" for HW accelerating devices, but it is probably too late to reject it from creation even if makes sense. Instead, just remove the check in unregister_vlan_dev(). Reported-by: Dmitry Vyukov <dvyukov@google.com> Fixes: ad1afb003939 ("vlan_dev: VLAN 0 should be treated as "no vlan tag" (802.1p packet)") Cc: Vlad Yasevich <vyasevich@gmail.com> Cc: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10Merge tag 'wireless-drivers-for-davem-2018-01-09' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers Kalle Valo says: ==================== wireless-drivers fixes for 4.15 Hopefully the last set of fixes for 4.15. iwlwifi * fix DMA mapping regression since v4.14 wcn36xx * fix dynamic power save which has been broken since the driver was commited ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10of_mdio: avoid MDIO bus removal when a PHY is missingMadalin Bucur
If one of the child devices is missing the of_mdiobus_register_phy() call will return -ENODEV. When a missing device is encountered the registration of the remaining PHYs is stopped and the MDIO bus will fail to register. Propagate all errors except ENODEV to avoid it. Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10caif_usb: use strlcpy() instead of strncpy()Xiongfeng Wang
gcc-8 reports net/caif/caif_usb.c: In function 'cfusbl_device_notify': ./include/linux/string.h:245:9: warning: '__builtin_strncpy' output may be truncated copying 15 bytes from a string of length 15 [-Wstringop-truncation] The compiler require that the input param 'len' of strncpy() should be greater than the length of the src string, so that '\0' is copied as well. We can just use strlcpy() to avoid this warning. Signed-off-by: Xiongfeng Wang <xiongfeng.wang@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10doc: clarification about setting SO_ZEROCOPYKornilios Kourtis
Signed-off-by: Kornilios Kourtis <kou@zurich.ibm.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10net: gianfar_ptp: move set_fipers() to spinlock protecting areaYangbo Lu
set_fipers() calling should be protected by spinlock in case that any interrupt breaks related registers setting and the function we expect. This patch is to move set_fipers() to spinlock protecting area in ptp_gianfar_adjtime(). Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10Merge branch 'sctp-Some-sockopt-optlen-fixes'David S. Miller
Marcelo Ricardo Leitner says: ==================== sctp: Some sockopt optlen fixes Hangbin Liu reported that some SCTP sockopt are allowing the user to get the kernel to allocate really large buffers by not having a ceiling on optlen. This patchset address this issue (in patch 2), replace an GFP_ATOMIC that isn't needed and avoid calculating the option size multiple times in some setsockopt. ==================== Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10sctp: make use of pre-calculated lenMarcelo Ricardo Leitner
Some sockopt handling functions were calculating the length of the buffer to be written to userspace and then calculating it again when actually writing the buffer, which could lead to some write not using an up-to-date length. This patch updates such places to just make use of the len variable. Also, replace some sizeof(type) to sizeof(var). Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10sctp: add a ceiling to optlen in some sockoptsMarcelo Ricardo Leitner
Hangbin Liu reported that some sockopt calls could cause the kernel to log a warning on memory allocation failure if the user supplied a large optlen value. That is because some of them called memdup_user() without a ceiling on optlen, allowing it to try to allocate really large buffers. This patch adds a ceiling by limiting optlen to the maximum allowed that would still make sense for these sockopt. Reported-by: Hangbin Liu <haliu@redhat.com> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10sctp: GFP_ATOMIC is not needed in sctp_setsockopt_eventsMarcelo Ricardo Leitner
So replace it with GFP_USER and also add __GFP_NOWARN. Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10Merge tag 'sound-4.15-rc8' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound Pull sound fixes from Takashi Iwai: "A collection of the last-minute small PCM fixes: - A workaround for the recent regression wrt PulseAudio - Removal of spurious WARN_ON() that is triggered by syzkaller - Fixes for aloop, hardening racy accesses - Fixes in PCM OSS emulation wrt the unabortable loops that may cause RCU stall" * tag 'sound-4.15-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ALSA: pcm: Allow aborting mutex lock at OSS read/write loops ALSA: pcm: Abort properly at pending signal in OSS read/write loops ALSA: aloop: Fix racy hw constraints adjustment ALSA: aloop: Fix inconsistent format due to incomplete rule ALSA: aloop: Release cable upon open error path ALSA: pcm: Workaround for weird PulseAudio behavior on rewind error ALSA: pcm: Add missing error checks in OSS emulation plugin builder ALSA: pcm: Remove incorrect snd_BUG_ON() usages
2018-01-10x86/alternatives: Fix optimize_nops() checkingBorislav Petkov
The alternatives code checks only the first byte whether it is a NOP, but with NOPs in front of the payload and having actual instructions after it breaks the "optimized' test. Make sure to scan all bytes before deciding to optimize the NOPs in there. Reported-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Kosina <jikos@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Andrew Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: https://lkml.kernel.org/r/20180110112815.mgciyf5acwacphkq@pd.tnic
2018-01-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf 2018-01-09 The following pull-request contains BPF updates for your *net* tree. The main changes are: 1) Prevent out-of-bounds speculation in BPF maps by masking the index after bounds checks in order to fix spectre v1, and add an option BPF_JIT_ALWAYS_ON into Kconfig that allows for removing the BPF interpreter from the kernel in favor of JIT-only mode to make spectre v2 harder, from Alexei. 2) Remove false sharing of map refcount with max_entries which was used in spectre v1, from Daniel. 3) Add a missing NULL psock check in sockmap in order to fix a race, from John. 4) Fix test_align BPF selftest case since a recent change in verifier rejects the bit-wise arithmetic on pointers earlier but test_align update was missing, from Alexei. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-10drm/vmwgfx: Potential off by one in vmw_view_add()Dan Carpenter
The vmw_view_cmd_to_type() function returns vmw_view_max (3) on error. It's one element beyond the end of the vmw_view_cotables[] table. My read on this is that it's possible to hit this failure. header->id comes from vmw_cmd_check() and it's a user controlled number between 1040 and 1225 so we can hit that error. But I don't have the hardware to test this code. Fixes: d80efd5cb3de ("drm/vmwgfx: Initial DX support") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com> Cc: <stable@vger.kernel.org>
2018-01-10xen/gntdev: Fix partial gntdev_mmap() cleanupRoss Lagerwall
When cleaning up after a partially successful gntdev_mmap(), unmap the successfully mapped grant pages otherwise Xen will kill the domain if in debug mode (Attempt to implicitly unmap a granted PTE) or Linux will kill the process and emit "BUG: Bad page map in process" if Xen is in release mode. This is only needed when use_ptemod is true because gntdev_put_map() will unmap grant pages itself when use_ptemod is false. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-01-10xen/gntdev: Fix off-by-one error when unmapping with holesRoss Lagerwall
If the requested range has a hole, the calculation of the number of pages to unmap is off by one. Fix it. Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2018-01-10gpio: Add missing open drain/source handling to gpiod_set_value_cansleep()Geert Uytterhoeven
Since commit f11a04464ae57e8d ("i2c: gpio: Enable working over slow can_sleep GPIOs"), probing the i2c RTC connected to an i2c-gpio bus on r8a7740/armadillo fails with: rtc-s35390a 0-0030: error resetting chip rtc-s35390a: probe of 0-0030 failed with error -5 More debug code reveals: i2c i2c-0: master_xfer[0] R, addr=0x30, len=1 i2c i2c-0: NAK from device addr 0x30 msg #0 s35390a_get_reg: ret = -6 Commit 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to actually be raw") moved open drain/source handling from gpiod_set_raw_value_commit() to gpiod_set_value(), but forgot to take into account that gpiod_set_value_cansleep() also needs this handling. The i2c protocol mandates that i2c signals are open drain, hence i2c communication fails. Fix this by adding the missing handling to gpiod_set_value_cansleep(), using a new common helper gpiod_set_value_nocheck(). Fixes: 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to actually be raw") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> [removed underscore syntax, added kerneldoc] Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-01-10drm/tegra: sor: Fix hang on Tegra124 eDPThierry Reding
The SOR0 found on Tegra124 and Tegra210 only supports eDP and LVDS and therefore has a slightly different clock tree than the SOR1 which does not support eDP, but HDMI and DP instead. Commit e1335e2f0cfc ("drm/tegra: sor: Reimplement pad clock") breaks setups with eDP because the sor->clk_out clock is uninitialized and therefore setting the parent clock (either the safe clock or either of the display PLLs) fails, which can cause hangs later on since there is no clock driving the module. Fix this by falling back to the module clock for sor->clk_out on those setups. This guarantees that the module will always be clocked by an enabled clock and hence prevents those hangs. Fixes: e1335e2f0cfc ("drm/tegra: sor: Reimplement pad clock") Reported-by: Guillaume Tucker <guillaume.tucker@collabora.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
2018-01-10powerpc/powernv: Check device-tree for RFI flush settingsOliver O'Halloran
New device-tree properties are available which tell the hypervisor settings related to the RFI flush. Use them to determine the appropriate flush instruction to use, and whether the flush is required. Signed-off-by: Oliver O'Halloran <oohall@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-10powerpc/pseries: Query hypervisor for RFI flush settingsMichael Neuling
A new hypervisor call is available which tells the guest settings related to the RFI flush. Use it to query the appropriate flush instruction(s), and whether the flush is required. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-10powerpc/64s: Support disabling RFI flush with no_rfi_flush and noptiMichael Ellerman
Because there may be some performance overhead of the RFI flush, add kernel command line options to disable it. We add a sensibly named 'no_rfi_flush' option, but we also hijack the x86 option 'nopti'. The RFI flush is not the same as KPTI, but if we see 'nopti' we can guess that the user is trying to avoid any overhead of Meltdown mitigations, and it means we don't have to educate every one about a different command line option. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-01-10powerpc/64s: Add support for RFI flush of L1-D cacheMichael Ellerman
On some CPUs we can prevent the Meltdown vulnerability by flushing the L1-D cache on exit from kernel to user mode, and from hypervisor to guest. This is known to be the case on at least Power7, Power8 and Power9. At this time we do not know the status of the vulnerability on other CPUs such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale CPUs. As more information comes to light we can enable this, or other mechanisms on those CPUs. The vulnerability occurs when the load of an architecturally inaccessible memory region (eg. userspace load of kernel memory) is speculatively executed to the point where its result can influence the address of a subsequent speculatively executed load. In order for that to happen, the first load must hit in the L1, because before the load is sent to the L2 the permission check is performed. Therefore if no kernel addresses hit in the L1 the vulnerability can not occur. We can ensure that is the case by flushing the L1 whenever we return to userspace. Similarly for hypervisor vs guest. In order to flush the L1-D cache on exit, we add a section of nops at each (h)rfi location that returns to a lower privileged context, and patch that with some sequence. Newer firmwares are able to advertise to us that there is a special nop instruction that flushes the L1-D. If we do not see that advertised, we fall back to doing a displacement flush in software. For guest kernels we support migration between some CPU versions, and different CPUs may use different flush instructions. So that we are prepared to migrate to a machine with a different flush instruction activated, we may have to patch more than one flush instruction at boot if the hypervisor tells us to. In the end this patch is mostly the work of Nicholas Piggin and Michael Ellerman. However a cast of thousands contributed to analysis of the issue, earlier versions of the patch, back ports testing etc. Many thanks to all of them. Tested-by: Jon Masters <jcm@redhat.com> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>