BMC/Intel-BMC/linux.git/arch/x86/include, branch dev-4.10

x86, pmem: Fix cache flushing for iovec write < 8 bytes

2017-05-20T12:30:57+00:00

commit 8376efd31d3d7c44bd05be337adde023cc531fa1 upstream. Commit 11e63f6d920d added cache flushing for unaligned writes from an iovec, covering the first and last cache line of a >= 8 byte write and the first cache line of a < 8 byte write. But an unaligned write of 2-7 bytes can still cover two cache lines, so make sure we flush both in that case. Fixes: 11e63f6d920d ("x86, pmem: fix broken __copy_user_nocache ...") Signed-off-by: Ben Hutchings Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

xen: Revert commits da72ff5bfcb0 and 72a9b186292d

2017-05-14T12:08:30+00:00

commit 84d582d236dc1f9085e741affc72e9ba061a67c2 upstream. Recent discussion (http://marc.info/?l=xen-devel&m=149192184523741) established that commit 72a9b186292d ("xen: Remove event channel notification through Xen PCI platform device") (and thus commit da72ff5bfcb0 ("partially revert "xen: Remove event channel notification through Xen PCI platform device"")) are unnecessary and, in fact, prevent HVM guests from booting on Xen releases prior to 4.0 Therefore we revert both of those commits. The summary of that discussion is below: Here is the brief summary of the current situation: Before the offending commit (72a9b186292): 1) INTx does not work because of the reset_watches path. 2) The reset_watches path is only taken if you have Xen > 4.0 3) The Linux Kernel by default will use vector inject if the hypervisor support. So even INTx does not work no body running the kernel with Xen > 4.0 would notice. Unless he explicitly disabled this feature either in the kernel or in Xen (and this can only be disabled by modifying the code, not user-supported way to do it). After the offending commit (+ partial revert): 1) INTx is no longer support for HVM (only for PV guests). 2) Any HVM guest The kernel will not boot on Xen < 4.0 which does not have vector injection support. Since the only other mode supported is INTx which. So based on this summary, I think before commit (72a9b186292) we were in much better position from a user point of view. Signed-off-by: Boris Ostrovsky Reviewed-by: Juergen Gross Cc: Boris Ostrovsky Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Konrad Rzeszutek Wilk Cc: Bjorn Helgaas Cc: Stefano Stabellini Cc: Julien Grall Cc: Vitaly Kuznetsov Cc: Paul Gortmaker Cc: Ross Lagerwall Cc: xen-devel@lists.xenproject.org Cc: linux-kernel@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: Anthony Liguori Cc: KarimAllah Ahmed Signed-off-by: Juergen Gross Signed-off-by: Greg Kroah-Hartman

x86/vdso: Plug race between mapping and ELF header setup

2017-04-21T07:32:38+00:00

commit 6fdc6dd90272ce7e75d744f71535cfbd8d77da81 upstream. The vsyscall32 sysctl can racy against a concurrent fork when it switches from disabled to enabled: arch_setup_additional_pages() if (vdso32_enabled) --> No mapping sysctl.vsysscall32() --> vdso32_enabled = true create_elf_tables() ARCH_DLINFO_IA32 if (vdso32_enabled) { --> Add VDSO entry with NULL pointer Make ARCH_DLINFO_IA32 check whether the VDSO mapping has been set up for the newly forked process or not. Signed-off-by: Thomas Gleixner Acked-by: Andy Lutomirski Cc: Peter Zijlstra Cc: Mathias Krause Link: http://lkml.kernel.org/r/20170410151723.602367196@linutronix.de Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

x86, pmem: fix broken __copy_user_nocache cache-bypass assumptions

2017-04-21T07:32:38+00:00

commit 11e63f6d920d6f2dfd3cd421e939a4aec9a58dcd upstream. Before we rework the "pmem api" to stop abusing __copy_user_nocache() for memcpy_to_pmem() we need to fix cases where we may strand dirty data in the cpu cache. The problem occurs when copy_from_iter_pmem() is used for arbitrary data transfers from userspace. There is no guarantee that these transfers, performed by dax_iomap_actor(), will have aligned destinations or aligned transfer lengths. Backstop the usage __copy_user_nocache() with explicit cache management in these unaligned cases. Yes, copy_from_iter_pmem() is now too big for an inline, but addressing that is saved for a later patch that moves the entirety of the "pmem api" into the pmem driver directly. Fixes: 5de490daec8b ("pmem: add copy_from_iter_pmem() and clear_pmem()") Cc: Cc: Jan Kara Cc: Jeff Moyer Cc: Ingo Molnar Cc: Christoph Hellwig Cc: "H. Peter Anvin" Cc: Al Viro Cc: Thomas Gleixner Cc: Matthew Wilcox Reviewed-by: Ross Zwisler Signed-off-by: Toshi Kani Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman

KVM: x86: cleanup the page tracking SRCU instance

2017-03-31T08:33:42+00:00

commit 2beb6dad2e8f95d710159d5befb390e4f62ab5cf upstream. SRCU uses a delayed work item. Skip cleaning it up, and the result is use-after-free in the work item callbacks. Reported-by: Dmitry Vyukov Suggested-by: Dmitry Vyukov Fixes: 0eb05bf290cfe8610d9680b49abef37febd1c38a Reviewed-by: Xiao Guangrong Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

x86/tlb: Fix tlb flushing when lguest clears PGE

2017-03-15T02:20:19+00:00

commit 2c4ea6e28dbf15ab93632c5c189f3948366b8885 upstream. Fengguang reported random corruptions from various locations on x86-32 after commits d2852a224050 ("arch: add ARCH_HAS_SET_MEMORY config") and 9d876e79df6a ("bpf: fix unlocking of jited image when module ronx not set") that uses the former. While x86-32 doesn't have a JIT like x86_64, the bpf_prog_lock_ro() and bpf_prog_unlock_ro() got enabled due to ARCH_HAS_SET_MEMORY, whereas Fengguang's test kernel doesn't have module support built in and therefore never had the DEBUG_SET_MODULE_RONX setting enabled. After investigating the crashes further, it turned out that using set_memory_ro() and set_memory_rw() didn't have the desired effect, for example, setting the pages as read-only on x86-32 would still let probe_kernel_write() succeed without error. This behavior would manifest itself in situations where the vmalloc'ed buffer was accessed prior to set_memory_*() such as in case of bpf_prog_alloc(). In cases where it wasn't, the page attribute changes seemed to have taken effect, leading to the conclusion that a TLB invalidate didn't happen. Moreover, it turned out that this issue reproduced with qemu in "-cpu kvm64" mode, but not for "-cpu host". When the issue occurs, change_page_attr_set_clr() did trigger a TLB flush as expected via __flush_tlb_all() through cpa_flush_range(), though. There are 3 variants for issuing a TLB flush: invpcid_flush_all() (depends on CPU feature bits X86_FEATURE_INVPCID, X86_FEATURE_PGE), cr4 based flush (depends on X86_FEATURE_PGE), and cr3 based flush. For "-cpu host" case in my setup, the flush used invpcid_flush_all() variant, whereas for "-cpu kvm64", the flush was cr4 based. Switching the kvm64 case to cr3 manually worked fine, and further investigating the cr4 one turned out that X86_CR4_PGE bit was not set in cr4 register, meaning the __native_flush_tlb_global_irq_disabled() wrote cr4 twice with the same value instead of clearing X86_CR4_PGE in the first write to trigger the flush. It turned out that X86_CR4_PGE was cleared from cr4 during init from lguest_arch_host_init() via adjust_pge(). The X86_FEATURE_PGE bit is also cleared from there due to concerns of using PGE in guest kernel that can lead to hard to trace bugs (see bff672e630a0 ("lguest: documentation V: Host") in init()). The CPU feature bits are cleared in dynamic boot_cpu_data, but they never propagated to __flush_tlb_all() as it uses static_cpu_has() instead of boot_cpu_has() for testing which variant of TLB flushing to use, meaning they still used the old setting of the host kernel. Clearing via setup_clear_cpu_cap(X86_FEATURE_PGE) so this would propagate to static_cpu_has() checks is too late at this point as sections have been patched already, so for now, it seems reasonable to switch back to boot_cpu_has(X86_FEATURE_PGE) as it was prior to commit c109bf95992b ("x86/cpufeature: Remove cpu_has_pge"). This lets the TLB flush trigger via cr3 as originally intended, properly makes the new page attributes visible and thus fixes the crashes seen by Fengguang. Fixes: c109bf95992b ("x86/cpufeature: Remove cpu_has_pge") Reported-by: Fengguang Wu Signed-off-by: Daniel Borkmann Cc: bp@suse.de Cc: Kees Cook Cc: "David S. Miller" Cc: netdev@vger.kernel.org Cc: Rusty Russell Cc: Alexei Starovoitov Cc: Linus Torvalds Cc: lkp@01.org Cc: Laura Abbott Link: http://lkml.kernrl.org/r/20170301125426.l4nf65rx4wahohyl@wfg-t540p.sh.intel.com Link: http://lkml.kernel.org/r/25c41ad9eca164be4db9ad84f768965b7eb19d9e.1489191673.git.daniel@iogearbox.net Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

x86/pkeys: Check against max pkey to avoid overflows

2017-03-12T05:44:15+00:00

commit 58ab9a088ddac4efe823471275859d64f735577e upstream. Kirill reported a warning from UBSAN about undefined behavior when using protection keys. He is running on hardware that actually has support for it, which is not widely available. The warning triggers because of very large shifts of integers when doing a pkey_free() of a large, invalid value. This happens because we never check that the pkey "fits" into the mm_pkey_allocation_map(). I do not believe there is any danger here of anything bad happening other than some aliasing issues where somebody could do: pkey_free(35); and the kernel would effectively execute: pkey_free(8); While this might be confusing to an app that was doing something stupid, it has to do something stupid and the effects are limited to the app shooting itself in the foot. Signed-off-by: Dave Hansen Cc: linux-kselftest@vger.kernel.org Cc: shuah@kernel.org Cc: kirill.shutemov@linux.intel.com Link: http://lkml.kernel.org/r/20170223222603.A022ED65@viggo.jf.intel.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

x86/CPU/AMD: Bring back Compute Unit ID

2017-02-05T11:18:45+00:00

Commit: a33d331761bc ("x86/CPU/AMD: Fix Bulldozer topology") restored the initial approach we had with the Fam15h topology of enumerating CU (Compute Unit) threads as cores. And this is still correct - they're beefier than HT threads but still have some shared functionality. Our current approach has a problem with the Mad Max Steam game, for example. Yves Dionne reported a certain "choppiness" while playing on v4.9.5. That problem stems most likely from the fact that the CU threads share resources within one CU and when we schedule to a thread of a different compute unit, this incurs latency due to migrating the working set to a different CU through the caches. When the thread siblings mask mirrors that aspect of the CUs and threads, the scheduler pays attention to it and tries to schedule within one CU first. Which takes care of the latency, of course. Reported-by: Yves Dionne Signed-off-by: Borislav Petkov Cc: # 4.9 Cc: Brice Goglin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yazen Ghannam Link: http://lkml.kernel.org/r/20170205105022.8705-1-bp@alien8.de Signed-off-by: Ingo Molnar

x86/microcode: Do not access the initrd after it has been freed

2017-01-30T08:32:42+00:00

When we look for microcode blobs, we first try builtin and if that doesn't succeed, we fallback to the initrd supplied to the kernel. However, at some point doing boot, that initrd gets jettisoned and we shouldn't access it anymore. But we do, as the below KASAN report shows. That's because find_microcode_in_initrd() doesn't check whether the initrd is still valid or not. So do that. ================================================================== BUG: KASAN: use-after-free in find_cpio_data Read of size 1 by task swapper/1/0 page:ffffea0000db9d40 count:0 mapcount:0 mapping: (null) index:0x1 flags: 0x100000000000000() raw: 0100000000000000 0000000000000000 0000000000000001 00000000ffffffff raw: dead000000000100 dead000000000200 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.10.0-rc5-debug-00075-g2dbde22 #3 Hardware name: Dell Inc. XPS 13 9360/0839Y6, BIOS 1.2.3 12/01/2016 Call Trace: dump_stack ? _atomic_dec_and_lock ? __dump_page kasan_report_error ? pointer ? find_cpio_data __asan_report_load1_noabort ? find_cpio_data find_cpio_data ? vsprintf ? dump_stack ? get_ucode_user ? print_usage_bug find_microcode_in_initrd __load_ucode_intel ? collect_cpu_info_early ? debug_check_no_locks_freed load_ucode_intel_ap ? collect_cpu_info ? trace_hardirqs_on ? flat_send_IPI_mask_allbutself load_ucode_ap ? get_builtin_firmware ? flush_tlb_func ? do_raw_spin_trylock ? cpumask_weight cpu_init ? trace_hardirqs_off ? play_dead_common ? native_play_dead ? hlt_play_dead ? syscall_init ? arch_cpu_idle_dead ? do_idle start_secondary start_cpu Memory state around the buggy address: ffff880036e74f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff880036e74f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff880036e75000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff880036e75080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff880036e75100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Reported-by: Andrey Ryabinin Tested-by: Andrey Ryabinin Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20170126165833.evjemhbqzaepirxo@pd.tnic Signed-off-by: Ingo Molnar

x86/unwind: Include __schedule() in stack traces

2017-01-12T08:28:28+00:00

In the following commit: 0100301bfdf5 ("sched/x86: Rewrite the switch_to() code") ... the layout of the 'inactive_task_frame' struct was designed to have a frame pointer header embedded in it, so that the unwinder could use the 'bp' and 'ret_addr' fields to report __schedule() on the stack (or ret_from_fork() for newly forked tasks which haven't actually run yet). Finish the job by changing get_frame_pointer() to return a pointer to inactive_task_frame's 'bp' field rather than 'bp' itself. This allows the unwinder to start one frame higher on the stack, so that it properly reports __schedule(). Reported-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Jones Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/598e9f7505ed0aba86e8b9590aa528c6c7ae8dcd.1483978430.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar