user/sven/linux.git/arch, branch v4.10.3

x86/tlb: Fix tlb flushing when lguest clears PGE

2017-03-15T02:20:19Z

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, mm: fix gup_pte_range() vs DAX mappings

2017-03-15T02:20:19Z

commit ef947b2529f918d9606533eb9c32b187ed6a5ede upstream. gup_pte_range() fails to check pte_allows_gup() before translating a DAX pte entry, pte_devmap(), to a page. This allows writes to read-only mappings, and bypasses the DAX cacheline dirty tracking due to missed 'mkwrite' faults. The gup_huge_pmd() path and the gup_huge_pud() path correctly check pte_allows_gup() before checking for _devmap() entries. Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Link: http://lkml.kernel.org/r/148804251312.36605.12665024794196605053.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Ross Zwisler Signed-off-by: Dan Williams Reported-by: Dave Hansen Reported-by: Ross Zwisler Cc: Xiong Zhou Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

xtensa: move parse_tag_fdt out of #ifdef CONFIG_BLK_DEV_INITRD

2017-03-15T02:20:13Z

commit 4ab18701c66552944188dbcd0ce0012729baab84 upstream. FDT tag parsing is not related to whether BLK_DEV_INITRD is configured or not, move it out of the corresponding #ifdef/#endif block. This fixes passing external FDT to the kernel configured w/o BLK_DEV_INITRD support. Signed-off-by: Max Filippov Signed-off-by: Greg Kroah-Hartman

s390: use correct input data address for setup_randomness

2017-03-15T02:20:08Z

commit 4920e3cf77347d7d7373552d4839e8d832321313 upstream. The current implementation of setup_randomness uses the stack address and therefore the pointer to the SYSIB 3.2.2 block as input data address. Furthermore the length of the input data is the number of virtual-machine description blocks which is typically one. This means that typically a single zero byte is fed to add_device_randomness. Fix both of these and use the address of the first virtual machine description block as input data address and also use the correct length. Fixes: bcfcbb6bae64 ("s390: add system information as device randomness") Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390: make setup_randomness work

2017-03-15T02:20:07Z

commit da8fd820f389a0e29080b14c61bf5cf1d8ef5ca1 upstream. Commit bcfcbb6bae64 ("s390: add system information as device randomness") intended to add some virtual machine specific information to the randomness pool. Unfortunately it uses the page allocator before it is ready to use. In result the page allocator always returns NULL and the setup_randomness function never adds anything to the randomness pool. To fix this use memblock_alloc and memblock_free instead. Fixes: bcfcbb6bae64 ("s390: add system information as device randomness") Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390/topology: correct allocation of topology information

2017-03-15T02:20:07Z

commit 8676caa4fb7fc02b2c76842a0024919d0caa4b8d upstream. The data stored by the STSI instruction can be up to a page in size but the memblock_virt_alloc allocation for tl_info only specifies 16 bytes. The memory after the short allocation is overwritten every time arch_update_cpu_topology is called. Fixes: 8c9105802235 "s390/numa: establish cpu to node mapping early" Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390: TASK_SIZE for kernel threads

2017-03-15T02:20:07Z

commit fb94a687d96c570d46332a4a890f1dcb7310e643 upstream. Return a sensible value if TASK_SIZE if called from a kernel thread. This gets us around an issue with copy_mount_options that does a magic size calculation "TASK_SIZE - (unsigned long)data" while in a kernel thread and data pointing to kernel space. Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

s390/kdump: Use "LINUX" ELF note name instead of "CORE"

2017-03-15T02:20:07Z

commit a4a81d8eebdc1d209d034f62a082a5131e4242b5 upstream. In binutils/libbfd (bfd/elf.c) it is enforced that all s390 specific ELF notes like e.g. NT_S390_PREFIX or NT_S390_CTRS have "LINUX" specified as note name. Otherwise the notes are ignored. For /proc/vmcore we currently use "CORE" for these notes. Up to now this has not been a real problem because the dump analysis tool "crash" does not check the note name. But it will break all programs that use libbfd for processing ELF notes. So fix this and use "LINUX" for all s390 specific notes to comply with libbfd. Reported-by: Philipp Rudo Reviewed-by: Philipp Rudo Signed-off-by: Michael Holzheu Signed-off-by: Martin Schwidefsky Signed-off-by: Greg Kroah-Hartman

KVM: VMX: use correct vmcs_read/write for guest segment selector/base

2017-03-15T02:20:05Z

commit 96794e4ed4d758272c486e1529e431efb7045265 upstream. Guest segment selector is 16 bit field and guest segment base is natural width field. Fix two incorrect invocations accordingly. Without this patch, build fails when aggressive inlining is used with ICC. Signed-off-by: Chao Peng Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: s390: Disable dirty log retrieval for UCONTROL guests

2017-03-15T02:20:05Z

commit e1e8a9624f7ba8ead4f056ff558ed070e86fa747 upstream. User controlled KVM guests do not support the dirty log, as they have no single gmap that we can check for changes. As they have no single gmap, kvm->arch.gmap is NULL and all further referencing to it for dirty checking will result in a NULL dereference. Let's return -EINVAL if a caller tries to sync dirty logs for a UCONTROL guest. Fixes: 15f36eb ("KVM: s390: Add proper dirty bitmap support to S390 kvm.") Signed-off-by: Janosch Frank Reported-by: Martin Schwidefsky Reviewed-by: Cornelia Huck Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman