kernel.git/arch/powerpc/mm, branch linux-4.11.y

mm: larger stack guard gap, between vmas

2017-06-24T05:06:22Z

commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov Original-patch-by: Michal Hocko Signed-off-by: Hugh Dickins Acked-by: Michal Hocko Tested-by: Helge Deller # parisc Signed-off-by: Linus Torvalds [wt: backport to 4.11: adjust context] Signed-off-by: Willy Tarreau Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Add physical address to Linux page table dump

2017-06-24T05:06:18Z

commit aaa229529244a1135b29353fefb001c430db79f0 upstream. The current page table dumper scans the Linux page tables and coalesces mappings with adjacent virtual addresses and similar PTE flags. This behaviour is somewhat broken when you consider the IOREMAP space where entirely unrelated mappings will appear to be virtually contiguous. This patch modifies the range coalescing so that only ranges that are both physically and virtually contiguous are combined. This patch also adds to the dump output the physical address at the start of each range. Fixes: 8eb07b187000 ("powerpc/mm: Dump linux pagetables") Signed-off-by: Oliver O'Halloran [mpe: Print the physicall address with 0x like the other addresses] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Fix crash in page table dump with huge pages

2017-05-25T13:46:23Z

commit bfb9956ab4d8242f4594b5f4bee534b935384fd9 upstream. The page table dump code doesn't know about huge pages, so currently it crashes (or walks random memory, usually leading to a crash), if it finds a huge page. On Book3S we only see huge pages in the Linux page tables when we're using the P9 Radix MMU. Teaching the code to properly handle huge pages is a bit more involved, so for now just prevent the crash. Fixes: 8eb07b187000 ("powerpc/mm: Dump linux pagetables") Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/iommu: Do not call PageTransHuge() on tail pages

2017-05-25T13:46:23Z

commit e889e96e98e8da97bd39e46b7253615eabe14397 upstream. The CMA pages migration code does not support compound pages at the moment so it performs few tests before proceeding to actual page migration. One of the tests - PageTransHuge() - has VM_BUG_ON_PAGE(PageTail()) as it is designed to be called on head pages only. Since we also test for PageCompound(), and it contains PageTail() and PageHead(), we can simplify the check by leaving just PageCompound() and therefore avoid possible VM_BUG_ON_PAGE. Fixes: 2e5bbb5461f1 ("KVM: PPC: Book3S HV: Migrate pinned pages out of CMA") Signed-off-by: Alexey Kardashevskiy Acked-by: Balbir Singh Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/mm: Add missing global TLB invalidate if cxl is active

2017-04-05T12:13:37Z

Commit 4c6d9acce1f4 ("powerpc/mm: Add hooks for cxl") converted local TLB invalidates to global if the cxl driver is active. This is necessary because the CAPP snoops invalidations to forward them to the PSL on the cxl adapter. However one path was forgotten. native_flush_hash_range() still does local TLB invalidates, as found out the hard way recently. This patch fixes it by following the same logic as previously: if the cxl driver is active, the local TLB invalidates are 'upgraded' to global. Fixes: 4c6d9acce1f4 ("powerpc/mm: Add hooks for cxl") Cc: stable@vger.kernel.org # v3.18+ Signed-off-by: Frederic Barrat Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman

Revert "powerpc/64: Disable use of radix under a hypervisor"

2017-03-21T05:50:28Z

This reverts commit 3f91a89d424a79f8082525db5a375e438887bb3e. Now that we do have the machinery for using the radix MMU under a hypervisor, the extra check and comment introduced in 3f91a89d424a are no longer correct. The result is that when booted under a hypervisor that only allows use of radix, we clear the MMU_FTR_TYPE_RADIX and then set it again, and print a warning about ignoring the disable_radix command line option, even though the command line does not include "disable_radix". Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman

Merge tag 'powerpc-4.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2017-03-07T18:46:10Z

Pull powerpc fixes from Michael Ellerman: "Five fairly small fixes for things that went in this cycle. A fairly large patch to rework the CAS logic on Power9, necessitated by a late change to the firmware API, and we can't boot without it. Three fixes going to stable, allowing more instructions to be emulated on LE, fixing a boot crash on 32-bit Freescale BookE machines, and the OPAL XICS workaround. And a patch from me to sort the selects under CONFIG PPC. Annoying churn, but worth it in the long run, and best for it to go in now to avoid conflicts. Thanks to: Alexey Kardashevskiy, Anton Blanchard, Balbir Singh, Gautham R. Shenoy, Laurentiu Tudor, Nicholas Piggin, Paul Mackerras, Ravi Bangoria, Sachin Sant, Shile Zhang, Suraj Jitindar Singh" * tag 'powerpc-4.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc: Sort the selects under CONFIG_PPC powerpc/64: Fix L1D cache shape vector reporting L1I values powerpc/64: Avoid panic during boot due to divide by zero in init_cache_info() powerpc: Update to new option-vector-5 format for CAS powerpc: Parse the command line before calling CAS powerpc/xics: Work around limitations of OPAL XICS priority handling powerpc/64: Fix checksum folding in csum_add() powerpc/powernv: Fix opal tracepoints with JUMP_LABEL=n powerpc/booke: Fix boot crash due to null hugepd powerpc: Fix compiling a BE kernel with a powerpc64le toolchain selftest/powerpc: Fix false failures for skipped tests powerpc/powernv: Fix bug due to labeling ambiguity in power_enter_stop powerpc/64: Invalidate process table caching after setting process table powerpc: emulate_step() tests for load/store instructions powerpc: Emulation support for load/store instructions on LE

powerpc: Update to new option-vector-5 format for CAS

2017-03-06T10:44:09Z

On POWER9 the ibm,client-architecture-support (CAS) negotiation process has been updated to change how the host to guest negotiation is done for the new hash/radix mmu as well as the nest mmu, process tables and guest translation shootdown (GTSE). This is documented in the unreleased PAPR ACR "CAS option vector additions for P9". The host tells the guest which options it supports in ibm,arch-vec-5-platform-support. The guest then chooses a subset of these to request in the CAS call and these are agreed to in the ibm,architecture-vec-5 property of the chosen node. Thus we read ibm,arch-vec-5-platform-support and make our selection before calling CAS. We then parse the ibm,architecture-vec-5 property of the chosen node to check whether we should run as hash or radix. ibm,arch-vec-5-platform-support format: index value pairs: ... index: Option vector 5 byte number val: Some representation of supported values Signed-off-by: Suraj Jitindar Singh Acked-by: Paul Mackerras [mpe: Don't print about unknown options, be consistent with OV5_FEAT] Signed-off-by: Michael Ellerman

powerpc/64: Invalidate process table caching after setting process table

2017-03-03T00:24:50Z

The POWER9 MMU reads and caches entries from the process table. When we kexec from one kernel to another, the second kernel sets its process table pointer but doesn't currently do anything to make the CPU invalidate any cached entries from the old process table. This adds a tlbie (TLB invalidate entry) instruction with parameters to invalidate caching of the process table after the new process table is installed. Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman

sched/headers: Prepare to remove the dependency from

2017-03-02T07:42:37Z

Update code that relied on sched.h including various MM types for them. This will allow us to remove the include from . Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar