kernel.git/arch/powerpc/mm, branch linux-4.17.y

powerpc/64s: Fix compiler store ordering to SLB shadow area

2018-08-03T05:47:37Z

[ Upstream commit 926bc2f100c24d4842b3064b5af44ae964c1d81c ] The stores to update the SLB shadow area must be made as they appear in the C code, so that the hypervisor does not see an entry with mismatched vsid and esid. Use WRITE_ONCE for this. GCC has been observed to elide the first store to esid in the update, which means that if the hypervisor interrupts the guest after storing to vsid, it could see an entry with old esid and new vsid, which may possibly result in memory corruption. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

KVM: PPC: Check if IOMMU page is contained in the pinned physical page

2018-07-28T05:57:12Z

commit 76fa4975f3ed12d15762bc979ca44078598ed8ee upstream. A VM which has: - a DMA capable device passed through to it (eg. network card); - running a malicious kernel that ignores H_PUT_TCE failure; - capability of using IOMMU pages bigger that physical pages can create an IOMMU mapping that exposes (for example) 16MB of the host physical memory to the device when only 64K was allocated to the VM. The remaining 16MB - 64K will be some other content of host memory, possibly including pages of the VM, but also pages of host kernel memory, host programs or other VMs. The attacking VM does not control the location of the page it can map, and is only allowed to map as many pages as it has pages of RAM. We already have a check in drivers/vfio/vfio_iommu_spapr_tce.c that an IOMMU page is contained in the physical page so the PCI hardware won't get access to unassigned host memory; however this check is missing in the KVM fastpath (H_PUT_TCE accelerated code). We were lucky so far and did not hit this yet as the very first time when the mapping happens we do not have tbl::it_userspace allocated yet and fall back to the userspace which in turn calls VFIO IOMMU driver, this fails and the guest does not retry, This stores the smallest preregistered page size in the preregistered region descriptor and changes the mm_iommu_xxx API to check this against the IOMMU page size. This calculates maximum page size as a minimum of the natural region alignment and compound page size. For the page shift this uses the shift returned by find_linux_pte() which indicates how the page is mapped to the current userspace - if the page is huge and this is not a zero, then it is a leaf pte and the page is mapped within the range. Fixes: 121f80ba68f1 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO") Cc: stable@vger.kernel.org # v4.12+ Signed-off-by: Alexey Kardashevskiy Reviewed-by: David Gibson Signed-off-by: Michael Ellerman Signed-off-by: Alexey Kardashevskiy Signed-off-by: Greg Kroah-Hartman

powerpc/64s/radix: Fix radix_kvm_prefetch_workaround paca access of not possible CPU

2018-07-03T09:26:51Z

commit 758380b8155f69b4e2f77f27562f8a7a466749d6 upstream. If possible CPUs are limited (e.g., by kexec), then the kvm prefetch workaround function can access the paca pointer for a !possible CPU. Fixes: d2e60075a3d44 ("powerpc/64: Use array of paca pointers and allocate pacas individually") Cc: stable@kernel.org Reported-by: Pridhiviraj Paidipeddi Tested-by: Pridhiviraj Paidipeddi Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/pkeys: Detach execute_only key on !PROT_EXEC

2018-07-03T09:26:50Z

commit eabdb8ca8690eedd461e61ea7780595fbbae8132 upstream. Disassociate the exec_key from a VMA if the VMA permission is not PROT_EXEC anymore. Otherwise the exec_only key continues to be associated with the vma, causing unexpected behavior. The problem was reported on x86 by Shakeel Butt, which is also applicable on powerpc. Fixes: 5586cf61e108 ("powerpc: introduce execute-only pkey") Cc: stable@vger.kernel.org # v4.16+ Reported-by: Shakeel Butt Signed-off-by: Ram Pai Reviewed-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Flush cache on memory hot(un)plug

2018-04-23T23:46:56Z

This patch adds support for flushing potentially dirty cache lines when memory is hot-plugged/hot-un-plugged. The support is currently limited to 64 bit systems. The bug was exposed when mappings for a device were actually hot-unplugged and plugged in back later. A similar issue was observed during the development of memtrace, but memtrace does it's own flushing of region via a custom routine. These patches do a flush both on hotplug/unplug to clear any stale data in the cache w.r.t mappings, there is a small race window where a clean cache line may be created again just prior to tearing down the mapping. The patches were tested by disabling the flush routines in memtrace and doing I/O on the trace file. The system immediately checkstops (quite reliablly if prior to the hot-unplug of the memtrace region, we memset the regions we are about to hot unplug). After these patches no custom flushing is needed in the memtrace code. Fixes: 9d5171a8f248 ("powerpc/powernv: Enable removal of memory for in memory tracing") Cc: stable@vger.kernel.org # v4.14+ Signed-off-by: Balbir Singh Acked-by: Reza Arbab Reviewed-by: Rashmica Gupta Signed-off-by: Michael Ellerman

Merge tag 'powerpc-4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2018-04-15T18:57:12Z

Pull powerpc fixes from Michael Ellerman: - Fix crashes when loading modules built with a different CONFIG_RELOCATABLE value by adding CONFIG_RELOCATABLE to vermagic. - Fix busy loops in the OPAL NVRAM driver if we get certain error conditions from firmware. - Remove tlbie trace points from KVM code that's called in real mode, because it causes crashes. - Fix checkstops caused by invalid tlbiel on Power9 Radix. - Ensure the set of CPU features we "know" are always enabled is actually the minimal set when we build with support for firmware supplied CPU features. Thanks to: Aneesh Kumar K.V, Anshuman Khandual, Nicholas Piggin. * tag 'powerpc-4.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/64s: Fix CPU_FTRS_ALWAYS vs DT CPU features powerpc/mm/radix: Fix checkstops caused by invalid tlbiel KVM: PPC: Book3S HV: trace_tlbie must not be called in realmode powerpc/8xx: Fix build with hugetlbfs enabled powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops powerpc/fscr: Enable interrupts earlier before calling get_user() powerpc/64s: Fix section mismatch warnings from setup_rfi_flush() powerpc/modules: Fix crashes by adding CONFIG_RELOCATABLE to vermagic

powerpc/mm/radix: Fix checkstops caused by invalid tlbiel

2018-04-12T13:49:55Z

In tlbiel_radix_set_isa300() we use the PPC_TLBIEL() macro to construct tlbiel instructions. The instruction takes 5 fields, two of which are registers, and the others are constants. But because it's constructed with inline asm the compiler doesn't know that. We got the constraint wrong on the 'r' field, using "r" tells the compiler to put the value in a register. The value we then get in the macro is the *register number*, not the value of the field. That means when we mask the register number with 0x1 we get 0 or 1 depending on which register the compiler happens to put the constant in, eg: li r10,1 tlbiel r8,r9,2,0,0 li r7,1 tlbiel r10,r6,0,0,1 If we're unlucky we might generate an invalid instruction form, for example RIC=0, PRS=1 and R=0, tlbiel r8,r7,0,1,0, this has been observed to cause machine checks: Oops: Machine check, sig: 7 [#1] CPU: 24 PID: 0 Comm: swapper NIP: 00000000000385f4 LR: 000000000100ed00 CTR: 000000000000007f REGS: c00000000110bb40 TRAP: 0200 MSR: 9000000000201003 CR: 48002222 XER: 20040000 CFAR: 00000000000385d0 DAR: 0000000000001c00 DSISR: 00000200 SOFTE: 1 If the machine check happens early in boot while we have MSR_ME=0 it will escalate into a checkstop and kill the box entirely. To fix it we could change the inline asm constraint to "i" which tells the compiler the value is a constant. But a better fix is to just pass a literal 1 into the macro, which bypasses any problems with inline asm constraints. Fixes: d4748276ae14 ("powerpc/64s: Improve local TLB flush for boot and MCE on POWER9") Cc: stable@vger.kernel.org # v4.16+ Signed-off-by: Michael Ellerman Reviewed-by: Nicholas Piggin

exec: pass stack rlimit into mm layout functions

2018-04-11T17:28:37Z

Patch series "exec: Pin stack limit during exec". Attempts to solve problems with the stack limit changing during exec continue to be frustrated[1][2]. In addition to the specific issues around the Stack Clash family of flaws, Andy Lutomirski pointed out[3] other places during exec where the stack limit is used and is assumed to be unchanging. Given the many places it gets used and the fact that it can be manipulated/raced via setrlimit() and prlimit(), I think the only way to handle this is to move away from the "current" view of the stack limit and instead attach it to the bprm, and plumb this down into the functions that need to know the stack limits. This series implements the approach. [1] 04e35f4495dd ("exec: avoid RLIMIT_STACK races with prlimit()") [2] 779f4e1c6c7c ("Revert "exec: avoid RLIMIT_STACK races with prlimit()"") [3] to security@kernel.org, "Subject: existing rlimit races?" This patch (of 3): Since it is possible that the stack rlimit can change externally during exec (either via another thread calling setrlimit() or another process calling prlimit()), provide a way to pass the rlimit down into the per-architecture mm layout functions so that the rlimit can stay in the bprm structure instead of sitting in the signal structure until exec is finalized. Link: http://lkml.kernel.org/r/1518638796-20819-2-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook Cc: Michal Hocko Cc: Ben Hutchings Cc: Willy Tarreau Cc: Hugh Dickins Cc: Oleg Nesterov Cc: "Jason A. Donenfeld" Cc: Rik van Riel Cc: Laura Abbott Cc: Greg KH Cc: Andy Lutomirski Cc: Ben Hutchings Cc: Brad Spengler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, migrate: remove reason argument from new_page_t

2018-04-11T17:28:32Z

No allocation callback is using this argument anymore. new_page_node used to use this parameter to convey node_id resp. migration error up to move_pages code (do_move_page_to_node_array). The error status never made it into the final status field and we have a better way to communicate node id to the status field now. All other allocation callbacks simply ignored the argument so we can drop it finally. [mhocko@suse.com: fix migration callback] Link: http://lkml.kernel.org/r/20180105085259.GH2801@dhcp22.suse.cz [akpm@linux-foundation.org: fix alloc_misplaced_dst_page()] [mhocko@kernel.org: fix build] Link: http://lkml.kernel.org/r/20180103091134.GB11319@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20180103082555.14592-3-mhocko@kernel.org Signed-off-by: Michal Hocko Reviewed-by: Zi Yan Cc: Andrea Reale Cc: Anshuman Khandual Cc: Kirill A. Shutemov Cc: Mike Kravetz Cc: Naoya Horiguchi Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/8xx: Fix build with hugetlbfs enabled

2018-04-11T02:00:23Z

8xx uses the slice code when hugetlbfs is enabled. We missed a header include on 8xx which resulted in the below build failure: config: mpc885_ads_defconfig + CONFIG_HUGETLBFS arch/powerpc/mm/slice.c: In function 'slice_get_unmapped_area': arch/powerpc/mm/slice.c:655:2: error: implicit declaration of function 'need_extra_context' arch/powerpc/mm/slice.c:656:3: error: implicit declaration of function 'alloc_extended_context' on PPC64 the mmu_context.h was included via linux/pkeys.h Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman