linux/kernel/memremap.c, branch v4.7

memremap: add arch specific hook for MEMREMAP_WB mappings

2016-04-04T08:26:41Z

Currently, the memremap code serves MEMREMAP_WB mappings directly from the kernel direct mapping, unless the region is in high memory, in which case it falls back to using ioremap_cache(). However, the semantics of ioremap_cache() are not unambiguously defined, and on ARM, it will actually result in a mapping type that differs from the attributes used for the linear mapping, and for this reason, the ioremap_cache() call fails if the region is part of the memory managed by the kernel. So instead, implement an optional hook 'arch_memremap_wb' whose default implementation calls ioremap_cache() as before, but which can be overridden by the architecture to do what is appropriate for it. Acked-by: Dan Williams Signed-off-by: Ard Biesheuvel

memremap: add MEMREMAP_WC flag

2016-03-22T22:36:02Z

Add a flag to memremap() for writecombine mappings. Mappings satisfied by this flag will not be cached, however writes may be delayed or combined into more efficient bursts. This is most suitable for buffers written sequentially by the CPU for use by other DMA devices. Signed-off-by: Brian Starkey Reviewed-by: Catalin Marinas Cc: Dan Williams Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memremap: don't modify flags

2016-03-22T22:36:02Z

These patches implement a MEMREMAP_WC flag for memremap(), which can be used to obtain writecombine mappings. This is then used for setting up dma_coherent_mem regions which use the DMA_MEMORY_MAP flag. The motivation is to fix an alignment fault on arm64, and the suggestion to implement MEMREMAP_WC for this case was made at [1]. That particular issue is handled in patch 4, which makes sure that the appropriate memset function is used when zeroing allocations mapped as IO memory. This patch (of 4): Don't modify the flags input argument to memremap(). MEMREMAP_WB is already a special case so we can check for it directly instead of clearing flag bits in each mapper. Signed-off-by: Brian Starkey Cc: Catalin Marinas Cc: Dan Williams Cc: Greg Kroah-Hartman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: fix two typos in comments for to_vmem_altmap()

2016-03-15T23:55:16Z

Commit 4b94ffdc4163 ("x86, mm: introduce vmem_altmap to augment vmemmap_populate()"), introduced the to_vmem_altmap() function. The comments in this function contain two typos (one misspelling of the Kconfig option CONFIG_SPARSEMEM_VMEMMAP, and one missing letter 'n'), let's fix them up. Signed-off-by: Andreas Ziegler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'core-resources-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2016-03-14T22:15:51Z

Pull ram resource handling changes from Ingo Molnar: "Core kernel resource handling changes to support NVDIMM error injection. This tree introduces a new I/O resource type, IORESOURCE_SYSTEM_RAM, for System RAM while keeping the current IORESOURCE_MEM type bit set for all memory-mapped ranges (including System RAM) for backward compatibility. With this resource flag it no longer takes a strcmp() loop through the resource tree to find "System RAM" resources. The new resource type is then used to extend ACPI/APEI error injection facility to also support NVDIMM" * 'core-resources-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ACPI/EINJ: Allow memory error injection to NVDIMM resource: Kill walk_iomem_res() x86/kexec: Remove walk_iomem_res() call with GART type x86, kexec, nvdimm: Use walk_iomem_res_desc() for iomem search resource: Add walk_iomem_res_desc() memremap: Change region_intersects() to take @flags and @desc arm/samsung: Change s3c_pm_run_res() to use System RAM type resource: Change walk_system_ram() to use System RAM type drivers: Initialize resource entry to zero xen, mm: Set IORESOURCE_SYSTEM_RAM to System RAM kexec: Set IORESOURCE_SYSTEM_RAM for System RAM arch: Set IORESOURCE_SYSTEM_RAM flag for System RAM ia64: Set System RAM type and descriptor x86/e820: Set System RAM type and descriptor resource: Add I/O resource descriptor resource: Handle resource flags properly resource: Add System RAM resource type

memremap: check pfn validity before passing to pfn_to_page()

2016-03-09T23:43:42Z

In memremap's helper function try_ram_remap(), we dereference a struct page pointer that was derived from a PFN that is known to be covered by a 'System RAM' iomem region, and is thus assumed to be a 'valid' PFN, i.e., a PFN that has a struct page associated with it and is covered by the kernel direct mapping. However, the assumption that there is a 1:1 relation between the System RAM iomem region and the kernel direct mapping is not universally valid on all architectures, and on ARM and arm64, 'System RAM' may include regions for which pfn_valid() returns false. Generally speaking, both __va() and pfn_to_page() should only ever be called on PFNs/physical addresses for which pfn_valid() returns true, so add that check to try_ram_remap(). Signed-off-by: Ard Biesheuvel Cc: Dan Williams Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: fix mixed zone detection in devm_memremap_pages

2016-03-09T23:43:42Z

The check for whether we overlap "System RAM" needs to be done at section granularity. For example a system with the following mapping: 100000000-37bffffff : System RAM 37c000000-837ffffff : Persistent Memory ...is unable to use devm_memremap_pages() as it would result in two zones colliding within a given section. Signed-off-by: Dan Williams Cc: Ross Zwisler Reviewed-by: Toshi Kani Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

list: kill list_force_poison()

2016-03-09T23:43:42Z

Given we have uninitialized list_heads being passed to list_add() it will always be the case that those uninitialized values randomly trigger the poison value. Especially since a list_add() operation will seed the stack with the poison value for later stack allocations to trip over. For example, see these two false positive reports: list_add attempted on force-poisoned entry WARNING: at lib/list_debug.c:34 [..] NIP [c00000000043c390] __list_add+0xb0/0x150 LR [c00000000043c38c] __list_add+0xac/0x150 Call Trace: __list_add+0xac/0x150 (unreliable) __down+0x4c/0xf8 down+0x68/0x70 xfs_buf_lock+0x4c/0x150 [xfs] list_add attempted on force-poisoned entry(0000000000000500), new->next == d0000000059ecdb0, new->prev == 0000000000000500 WARNING: at lib/list_debug.c:33 [..] NIP [c00000000042db78] __list_add+0xa8/0x140 LR [c00000000042db74] __list_add+0xa4/0x140 Call Trace: __list_add+0xa4/0x140 (unreliable) rwsem_down_read_failed+0x6c/0x1a0 down_read+0x58/0x60 xfs_log_commit_cil+0x7c/0x600 [xfs] Fixes: commit 5c2c2587b132 ("mm, dax, pmem: introduce {get|put}_dev_pagemap() for dax-gup") Signed-off-by: Dan Williams Reported-by: Eryu Guan Tested-by: Eryu Guan Cc: Ross Zwisler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'v4.5-rc6' into core/resources, to resolve conflict

2016-03-04T11:12:08Z

Signed-off-by: Ingo Molnar

Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2016-02-26T02:54:53Z

Pull libnvdimm fixes from Dan Williams: - Two fixes for compatibility with the ACPI 6.1 specification. Without these fixes multi-interface DIMMs will fail to be probed, and address range scrub commands to find memory errors will give results that the kernel will mis-interpret. For multi-interface DIMMs Linux will accept either the original 6.0 implementation or 6.1. For address range scrub we'll only support 6.1 since ACPI formalized this DSM differently than the original example [1] implemented in v4.2. The expectation is that production systems will only ever ship the ACPI 6.1 address range scrub command definition. - The wider async address range scrub work targeting 4.6 discovered that the original synchronous implementation in 4.5 is not sizing its return buffer correctly. - Arnd caught that my recent fix to the size of the pfn_t flags missed updating the flags variable used in the pmem driver. - Toshi found that we mishandle the memremap() return value in devm_memremap(). * 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: nvdimm: use 'u64' for pfn flags devm_memremap: Fix error value when memremap failed nfit: update address range scrub commands to the acpi 6.1 format libnvdimm, tools/testing/nvdimm: fix 'ars_status' output buffer sizing nfit: fix multi-interface dimm handling, acpi6.1 compatibility