kernel.git/arch/arc/mm, branch linux-4.13.y

ARC: Re-enable MMU upon Machine Check exception

2017-09-27T12:43:19Z

commit 1ee55a8f7f6b7ca4c0c59e0b4b4e3584a085c2d3 upstream. I recently came upon a scenario where I would get a double fault machine check exception tiriggered by a kernel module. However the ensuing crash stacktrace (ksym lookup) was not working correctly. Turns out that machine check auto-disables MMU while modules are allocated in kernel vaddr spapce. This patch re-enables the MMU before start printing the stacktrace making stacktracing of modules work upon a fatal exception. Signed-off-by: Jose Abreu Reviewed-by: Alexey Brodkin Signed-off-by: Vineet Gupta [vgupta: moved code into low level handler to avoid in 2 places] Signed-off-by: Greg Kroah-Hartman

Merge tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

2017-08-21T20:30:36Z

Pull ARC fixes from Vineet Gupta: - PAE40 related updates - SLC errata for region ops - intc line masking by default * tag 'arc-4.13-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: arc: Mask individual IRQ lines during core INTC init ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses ARC: dma: implement dma_unmap_page and sg variant ARCv2: SLC: Make sure busy bit is set properly for region ops ARC: [plat-sim] Include this platform unconditionally ARC: [plat-axs10x]: prepare dts files for enabling PAE40 on axs103 ARC: defconfig: Cleanup from old Kconfig options

ARCv2: PAE40: set MSB even if !CONFIG_ARC_HAS_PAE40 but PAE exists in SoC

2017-08-04T08:26:35Z

PAE40 confiuration in hardware extends some of the address registers for TLB/cache ops to 2 words. So far kernel was NOT setting the higher word if feature was not enabled in software which is wrong. Those need to be set to 0 in such case. Normally this would be done in the cache flush / tlb ops, however since these registers only exist conditionally, this would have to be conditional to a flag being set on boot which is expensive/ugly - specially for the more common case of PAE exists but not in use. Optimize that by zero'ing them once at boot - nobody will write to them afterwards Cc: stable@vger.kernel.org #4.4+ Signed-off-by: Vineet Gupta

ARCv2: PAE40: Explicitly set MSB counterpart of SLC region ops addresses

2017-08-04T08:26:34Z

It is necessary to explicitly set both SLC_AUX_RGN_START1 and SLC_AUX_RGN_END1 which hold MSB bits of the physical address correspondingly of region start and end otherwise SLC region operation is executed in unpredictable manner Without this patch, SLC flushes on HSDK (IOC disabled) were taking seconds. Cc: stable@vger.kernel.org #4.4+ Reported-by: Vladimir Kondratiev Signed-off-by: Alexey Brodkin Signed-off-by: Vineet Gupta [vgupta: PAR40 regs only written if PAE40 exist]

ARC: dma: implement dma_unmap_page and sg variant

2017-08-04T08:26:33Z

Signed-off-by: Vineet Gupta

ARCv2: SLC: Make sure busy bit is set properly for region ops

2017-08-04T08:20:07Z

c70c473396cb "ARCv2: SLC: Make sure busy bit is set properly on SLC flushing" fixes problem for entire SLC operation where the problem was initially caught. But given a nature of the issue it is perfectly possible for busy bit to be read incorrectly even when region operation was started. So extending initial fix for regional operation as well. Signed-off-by: Alexey Brodkin Cc: stable@vger.kernel.org #4.10 Signed-off-by: Vineet Gupta

dma-coherent: introduce interface for default DMA pool

2017-07-20T14:09:10Z

Christoph noticed [1] that default DMA pool in current form overload the DMA coherent infrastructure. In reply, Robin suggested [2] to split the per-device vs. global pool interfaces, so allocation/release from default DMA pool is driven by dma ops implementation. This patch implements Robin's idea and provide interface to allocate/release/mmap the default (aka global) DMA pool. To make it clear that existing *_from_coherent routines work on per-device pool rename them to *_from_dev_coherent. [1] https://lkml.org/lkml/2017/7/7/370 [2] https://lkml.org/lkml/2017/7/7/431 Cc: Vineet Gupta Cc: Russell King Cc: Catalin Marinas Cc: Will Deacon Cc: Ralf Baechle Suggested-by: Robin Murphy Tested-by: Andras Szemzo Reviewed-by: Robin Murphy Signed-off-by: Vladimir Murzin Signed-off-by: Christoph Hellwig

mm: larger stack guard gap, between vmas

2017-06-19T13:50:20Z

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

Merge tag 'arc-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

2017-05-09T17:10:15Z

Pull ARC updates from Vineet Gupta: - AXS10x platform clk updates for I2S, PGU - add region based cache flush operation for ARCv2 cores - enforce PAE40 dependency on HIGHMEM - ptrace support for additional regs in ARCv2 cores - fix build failure in linux-next dut to a header include ordering change * tag 'arc-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: Revert "ARCv2: Allow enabling PAE40 w/o HIGHMEM" ARC: mm: fix build failure in linux-next for UP builds ARCv2: ptrace: provide regset for accumulator/r30 regs elf: Add ARCv2 specific core note section ARCv2: mm: micro-optimize region flush generated code ARCv2: mm: Merge 2 updates to DC_CTRL for region flush ARCv2: mm: Implement cache region flush operations ARC: mm: Move full_page computation into cache version agnostic wrapper arc: axs10x: Fix ARC PGU default clock frequency arc: axs10x: Add DT bindings for I2S audio playback

ARCv2: mm: Merge 2 updates to DC_CTRL for region flush

2017-05-02T23:16:07Z