- 05 Jun, 2020 40 commits
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David Hildenbrand authored
The comment in add_memory_resource() is stale: hotadd_new_pgdat() will no longer call get_pfn_range_for_nid(), as a hotadded pgdat will simply span no pages at all, until memory is moved to the zone/node via move_pfn_range_to_zone() - e.g., when onlining memory blocks. The only archs that care about memblocks for hotplugged memory (either for iterating over all system RAM or testing for memory validity) are arm64, s390x, and powerpc - due to CONFIG_ARCH_KEEP_MEMBLOCK. Without CONFIG_ARCH_KEEP_MEMBLOCK, we can simply stop messing with memblocks. Signed-off-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Acked-by:
Mike Rapoport <rppt@linux.ibm.com> Acked-by:
Michal Hocko <mhocko@suse.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Link: http://lkml.kernel.org/r/20200422155353.25381-3-david@redhat.comSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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David Hildenbrand authored
Patch series "mm/memory_hotplug: handle memblocks only with CONFIG_ARCH_KEEP_MEMBLOCK", v1. A hotadded node/pgdat will span no pages at all, until memory is moved to the zone/node via move_pfn_range_to_zone() -> resize_pgdat_range - e.g., when onlining memory blocks. We don't have to initialize the node_start_pfn to the memory we are adding. This patch (of 2): Especially, there is an inconsistency: - Hotplugging memory to a memory-less node with cpus: node_start_pf == 0 - Offlining and removing last memory from a node: node_start_pfn == 0 - Hotplugging memory to a memory-less node without cpus: node_start_pfn != 0 As soon as memory is onlined, node_start_pfn is overwritten with the actual start. E.g., when adding two DIMMs but only onlining one of both, only that DIMM (with online memory blocks) is spanned by the node. Currently, the validity of node_start_pfn really is linked to node_spanned_pages != 0. With node_spanned_pages == 0 (e.g., before onlining memory), it has no meaning. So let's stop setting node_start_pfn, just to be overwritten via move_pfn_range_to_zone(). This avoids confusion when looking at the code, wondering which magic will be performed with the node_start_pfn in this function, when hotadding a pgdat. Signed-off-by:
Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Michal Hocko <mhocko@suse.com> Link: http://lkml.kernel.org/r/20200422155353.25381-1-david@redhat.com Link: http://lkml.kernel.org/r/20200422155353.25381-2-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Fortunately, all users of is_mem_section_removable() are gone. Get rid of it, including some now unnecessary functions. Signed-off-by:
Wei Yang <richard.weiyang@gmail.com> Reviewed-by:
Baoquan He <bhe@redhat.com> Acked-by:
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David Hildenbrand authored
In commit 53cdc1cb ("drivers/base/memory.c: indicate all memory blocks as removable"), the user space interface to compute whether a memory block can be offlined (exposed via /sys/devices/system/memory/memoryX/removable) has effectively been deprecated. We want to remove the leftovers of the kernel implementation. When offlining a memory block (mm/memory_hotplug.c:__offline_pages()), we'll start by: 1. Testing if it contains any holes, and reject if so 2. Testing if pages belong to different zones, and reject if so 3. Isolating the page range, checking if it contains any unmovable pages Using is_mem_section_removable() before trying to offline is not only racy, it can easily result in false positives/negatives. Let's stop manually checking is_mem_section_removable(), and let device_offline() handle it completely instead. We can remove the racy is_mem_section_removable() implementation next. We now take more locks (e.g., memory hotplug lock when offlining and the zone lock when isolating), but maybe we should optimize that implementation instead if this ever becomes a real problem (after all, memory unplug is already an expensive operation). We started using is_mem_section_removable() in commit 51925fb3 ("powerpc/pseries: Implement memory hotplug remove in the kernel"), with the initial hotremove support of lmbs. Signed-off-by:
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Vishal Verma authored
A misbehaving qemu created a situation where the ACPI SRAT table advertised one fewer proximity domains than intended. The NFIT table did describe all the expected proximity domains. This caused the device dax driver to assign an impossible target_node to the device, and when hotplugged as system memory, this would fail with the following signature: BUG: kernel NULL pointer dereference, address: 0000000000000088 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 80000001767d4067 P4D 80000001767d4067 PUD 10e0c4067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 4 PID: 22737 Comm: kswapd3 Tainted: G O 5.6.0-rc5 #9 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:prepare_kswapd_sleep+0x7c/0xc0 Code: 89 df e8 87 fd ff ff 89 c2 31 c0 84 d2 74 e6 0f 1f 44 00 00 48 8b 05 fb af 7a 01 48 63 93 88 1d 01 00 48 8b 84 d0 20 0f 00 00 <48> 3b 98 88 00 00 00 75 28 f0 80 a0 80 00 00 00 fe f0 80 a3 38 20 RSP: 0018:ffffc900017a3e78 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8881209e0000 RCX: 0000000000000000 RDX: 0000000000000003 RSI: 0000000000000000 RDI: ffff8881209e0e80 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000008000 R10: 0000000000000000 R11: 0000000000000003 R12: 0000000000000003 R13: 0000000000000003 R14: 0000000000000000 R15: ffffc900017a3ec8 FS: 0000000000000000(0000) GS:ffff888318c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000088 CR3: 0000000120b50002 CR4: 00000000001606e0 Call Trace: kswapd+0x103/0x520 kthread+0x120/0x140 ret_from_fork+0x3a/0x50 Add a check in the add_memory path to fail if the node to which we are adding memory is in the node_possible_map Signed-off-by:Vishal Verma <vishal.l.verma@intel.com> Signed-off-by:
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Waiman Long authored
For kvmalloc'ed data object that contains sensitive information like cryptographic keys, we need to make sure that the buffer is always cleared before freeing it. Using memset() alone for buffer clearing may not provide certainty as the compiler may compile it away. To be sure, the special memzero_explicit() has to be used. This patch introduces a new kvfree_sensitive() for freeing those sensitive data objects allocated by kvmalloc(). The relevant places where kvfree_sensitive() can be used are modified to use it. Fixes: 4f088249 ("KEYS: Avoid false positive ENOMEM error on key read") Suggested-by:
Waiman Long <longman@redhat.com> Signed-off-by:
Eric Biggers <ebiggers@google.com> Acked-by:
David Howells <dhowells@redhat.com> Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Cc: James Morris <jmorris@namei.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Joe Perches <joe@perches.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Rientjes <rientjes@google.com> Cc: Uladzislau Rezki <urezki@gmail.com> Link: http://lkml.kernel.org/r/20200407200318.11711-1-longman@redhat.comSigned-off-by:
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Ira Weiny authored
Most architectures define kmap_prot to be PAGE_KERNEL. Let sparc and xtensa define there own and define PAGE_KERNEL as the default if not overridden. [akpm@linux-foundation.org: coding style fixes] Suggested-by:
Christoph Hellwig <hch@infradead.org> Signed-off-by:
Ira Weiny <ira.weiny@intel.com> Signed-off-by:
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Ira Weiny authored
linux/highmem.h has not been needed for the pte_offset_map => kmap_atomic use in sparc for some time (~2002) Remove this include. Suggested-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Ira Weiny authored
parisc reimplements the kmap calls except to flush its dcache. This is arguably an abuse of kmap but regardless it is messy and confusing. Remove the duplicate code and have parisc define ARCH_HAS_FLUSH_ON_KUNMAP for a kunmap_flush_on_unmap() architecture specific call to flush the cache. Suggested-by:
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Ira Weiny authored
kmap_atomic_to_page() has no callers and is only defined on 1 arch and declared on another. Remove it. Suggested-by:
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Ira Weiny authored
kmap_atomic_prot() is now exported by all architectures. Use this function rather than open coding a driver specific kmap_atomic. [arnd@arndb.de: include linux/highmem.h] Link: http://lkml.kernel.org/r/20200508220150.649044-1-arnd@arndb.deSigned-off-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Christian König <christian.koenig@amd.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Acked-by:
Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Zankel <chris@zankel.net> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Helge Deller <deller@gmx.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200507150004.1423069-12-ira.weiny@intel.comSigned-off-by:
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Ira Weiny authored
To support kmap_atomic_prot(), all architectures need to support protections passed to their kmap_atomic_high() function. Pass protections into kmap_atomic_high() and change the name to kmap_atomic_high_prot() to match. Then define kmap_atomic_prot() as a core function which calls kmap_atomic_high_prot() when needed. Finally, redefine kmap_atomic() as a wrapper of kmap_atomic_prot() with the default kmap_prot exported by the architectures. Signed-off-by:
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Ira Weiny authored
To support kmap_atomic_prot() on all architectures each arch must support protections passed in to them. Change csky, mips, nds32 and xtensa to use their global constant kmap_prot rather than a hard coded value which was equal. Signed-off-by:
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Ira Weiny authored
We want to support kmap_atomic_prot() on all architectures and it makes sense to define kmap_atomic() to use the default kmap_prot. So we ensure all arch's have a globally available kmap_prot either as a define or exported symbol. Signed-off-by:
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Ira Weiny authored
Every single architecture (including !CONFIG_HIGHMEM) calls... pagefault_enable(); preempt_enable(); ... before returning from __kunmap_atomic(). Lift this code into the kunmap_atomic() macro. While we are at it rename __kunmap_atomic() to kunmap_atomic_high() to be consistent. [ira.weiny@intel.com: don't enable pagefault/preempt twice] Link: http://lkml.kernel.org/r/20200518184843.3029640-1-ira.weiny@intel.com [akpm@linux-foundation.org: coding style fixes] Signed-off-by:
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Ira Weiny authored
Every arch has the same code to ensure atomic operations and a check for !HIGHMEM page. Remove the duplicate code by defining a core kmap_atomic() which only calls the arch specific kmap_atomic_high() when the page is high memory. [akpm@linux-foundation.org: coding style fixes] Signed-off-by:
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Ira Weiny authored
During this kmap() conversion series we must maintain bisect-ability. To do this, kmap_atomic_prot() in x86, powerpc, and microblaze need to remain functional. Create a temporary inline version of kmap_atomic_prot within these architectures so we can rework their kmap_atomic() calls and then lift kmap_atomic_prot() to the core. Suggested-by:
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Ira Weiny authored
All architectures do exactly the same thing for kunmap(); remove all the duplicate definitions and lift the call to the core. This also has the benefit of changing kmap_unmap() on a number of architectures to be an inline call rather than an actual function. [akpm@linux-foundation.org: fix CONFIG_HIGHMEM=n build on various architectures] Signed-off-by:
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Ira Weiny authored
The kmap code for all the architectures is almost 100% identical. Lift the common code to the core. Use ARCH_HAS_KMAP_FLUSH_TLB to indicate if an arch defines kmap_flush_tlb() and call if if needed. This also has the benefit of changing kmap() on a number of architectures to be an inline call rather than an actual function. Signed-off-by:
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Ira Weiny authored
Move the kmap() build bug to kmap_init() to facilitate patches to lift kmap() to the core. Signed-off-by:
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Ira Weiny authored
Patch series "Remove duplicated kmap code", v3. The kmap infrastructure has been copied almost verbatim to every architecture. This series consolidates obvious duplicated code by defining core functions which call into the architectures only when needed. Some of the k[un]map_atomic() implementations have some similarities but the similarities were not sufficient to warrant further changes. In addition we remove a duplicate implementation of kmap() in DRM. This patch (of 15): Replace the use of BUG_ON(in_interrupt()) in the kmap() and kunmap() in favor of might_sleep(). Besides the benefits of might_sleep(), this normalizes the implementations such that they can be made generic in subsequent patches. Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Reviewed-by:
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Jeongtae Park authored
There is a typo in comment, fix it. "nother" -> "another" Signed-off-by:
Jeongtae Park <jtp.park@samsung.com> Signed-off-by:
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Anshuman Khandual authored
This adds tests which will validate architecture page table helpers and other accessors in their compliance with expected generic MM semantics. This will help various architectures in validating changes to existing page table helpers or addition of new ones. This test covers basic page table entry transformations including but not limited to old, young, dirty, clean, write, write protect etc at various level along with populating intermediate entries with next page table page and validating them. Test page table pages are allocated from system memory with required size and alignments. The mapped pfns at page table levels are derived from a real pfn representing a valid kernel text symbol. This test gets called via late_initcall(). This test gets built and run when CONFIG_DEBUG_VM_PGTABLE is selected. Any architecture, which is willing to subscribe this test will need to select ARCH_HAS_DEBUG_VM_PGTABLE. For now this is limited to arc, arm64, x86, s390 and powerpc platforms where the test is known to build and run successfully Going forward, other architectures too can subscribe the test after fixing any build or runtime problems with their page table helpers. Folks interested in making sure that a given platform's page table helpers conform to expected generic MM semantics should enable the above config which will just trigger this test during boot. Any non conformity here will be reported as an warning which would need to be fixed. This test will help catch any changes to the agreed upon semantics expected from generic MM and enable platforms to accommodate it thereafter. [anshuman.khandual@arm.com: v17] Link: http://lkml.kernel.org/r/1587436495-22033-3-git-send-email-anshuman.khandual@arm.com [anshuman.khandual@arm.com: v18] Link: http://lkml.kernel.org/r/1588564865-31160-3-git-send-email-anshuman.khandual@arm.comSuggested-by:
Catalin Marinas <catalin.marinas@arm.com> Signed-off-by:
Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by:
Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by:
Qian Cai <cai@lca.pw> Signed-off-by:
Ingo Molnar <mingo@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Link: http://lkml.kernel.org/r/1583919272-24178-1-git-send-email-anshuman.khandual@arm.comSigned-off-by:
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Anshuman Khandual authored
Patch series "mm/debug: Add tests validating architecture page table helpers", v18. This adds a test validation for architecture exported page table helpers. Patch adds basic transformation tests at various levels of the page table. This test was originally suggested by Catalin during arm64 THP migration RFC discussion earlier. Going forward it can include more specific tests with respect to various generic MM functions like THP, HugeTLB etc and platform specific tests. https://lore.kernel.org/linux-mm/20190628102003.GA56463@arrakis.emea.arm.com/ This patch (of 2): This just defines mm_p4d_folded() to check whether P4D page table level is folded at runtime. Signed-off-by:
Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by:
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Mike Rapoport authored
There are no architectures that use include/asm-generic/5level-fixup.h therefore it can be removed along with __ARCH_HAS_5LEVEL_HACK define and the code it surrounds Signed-off-by:
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Mike Rapoport authored
No architecture defines __ARCH_USE_5LEVEL_HACK and therefore pgtable-nop4d-hack.h will be never actually included. Remove it. Signed-off-by:
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Mike Rapoport authored
The unicore32 architecture has 2 level page tables and asm-generic/pgtable-nopmd.h and explicit casts from pud_t to pgd_t for page table folding. Add p4d walk in the only place that actually unfolds the pud level and remove __ARCH_USE_5LEVEL_HACK. Signed-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK. Signed-off-by:
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Mike Rapoport authored
The __pXd_offset() macros are identical to the pXd_index() macros and there is no point to keep both of them. All architectures define and use pXd_index() so let's keep only those to make mips consistent with the rest of the kernel. Signed-off-by:
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Geert Uytterhoeven authored
- Convert from printk() to pr_*(), - Add missing continuations, - Use "%llx" to format u64, - Join multiple prints in show_fault_oops() into a single print. Signed-off-by:
Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate and replace 5level-fixup.h with pgtable-nop4d.h. [rppt@linux.ibm.com: powerpc/xmon: drop unused pgdir varialble in show_pte() function] Link: http://lkml.kernel.org/r/20200519181454.GI1059226@linux.ibm.com [rppt@linux.ibm.com; build fix] Link: http://lkml.kernel.org/r/20200423141845.GI13521@linux.ibm.comSigned-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK. Signed-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate and remove usage of __ARCH_USE_5LEVEL_HACK. Signed-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate, remove usage of __ARCH_USE_5LEVEL_HACK and replace 5level-fixup.h with pgtable-nop4d.h Signed-off-by:
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Mike Rapoport authored
The hexagon architecture has 2 level page tables and as such most of the page table folding is already implemented in asm-generic/pgtable-nopmd.h. Fixup the only place in arch/hexagon to unfold the p4d level and remove __ARCH_USE_5LEVEL_HACK. Signed-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate, replace 5level-fixup.h with pgtable-nop4d.h and remove __ARCH_USE_5LEVEL_HACK. [arnd@arndb.de: fix gcc-10 shift warning] Link: http://lkml.kernel.org/r/20200429185657.4085975-1-arnd@arndb.deSigned-off-by:
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Mike Rapoport authored
Implement primitives necessary for the 4th level folding, add walks of p4d level where appropriate, and remove __ARCH_USE_5LEVEL_HACK. [rppt@linux.ibm.com: fix kexec] Link: http://lkml.kernel.org/r/20200508174232.GA759899@linux.ibm.comSigned-off-by:
Marek Szyprowski <m.szyprowski@samsung.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: James Morse <james.morse@arm.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Julien Thierry <julien.thierry.kdev@gmail.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Marc Zyngier <maz@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200414153455.21744-3-rppt@kernel.orgSigned-off-by:
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Mike Rapoport authored
Patch series "mm: remove __ARCH_HAS_5LEVEL_HACK", v4. These patches convert several architectures to use page table folding and remove __ARCH_HAS_5LEVEL_HACK along with include/asm-generic/5level-fixup.h and include/asm-generic/pgtable-nop4d-hack.h. With that we'll have a single and consistent way of dealing with page table folding instead of a mix of three existing options. The changes are mostly about mechanical replacement of pgd accessors with p4d ones and the addition of higher levels to page table traversals. This patch (of 14): h8300 is a nommu architecture and does not require fixup for upper layers of the page tables because it is already handled by the generic nommu implementation. Remove definition of __ARCH_USE_5LEVEL_HACK in arch/h8300/include/asm/pgtable.h Signed-off-by:
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Feng Tang authored
This check was added by commit 82f71ae4 ("mm: catch memory commitment underflow") in 2014 to have a safety check for issues which have been fixed. And there has been few report caught by it, as described in its commit log: : This shouldn't happen any more - the previous two patches fixed : the committed_as underflow issues. But it was really found by Qian Cai when he used the LTP memory stress suite to test a RFC patchset, which tries to improve scalability of per-cpu counter 'vm_committed_as', by chosing a bigger 'batch' number for loose overcommit policies (OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS), while keeping current number for OVERCOMMIT_NEVER. With that patchset, when system firstly uses a loose policy, the 'vm_committed_as' count could be a big negative value, as its big 'batch' number allows a big deviation, then when the policy is changed to OVERCOMMIT_NEVER, the 'batch' will be decreased to a much smaller value, thus hits this WARN check. To mitigate this, one proposed solution is to queue work on all online CPUs to do a local sync for 'vm_committed_as' when changing policy to OVERCOMMIT_NEVER, plus some global syncing to garante the case won't be hit. But this solution is costy and slow, given this check hasn't shown real trouble or benefit, simply drop it from one hot path of MM. And perf stats does show some tiny saving for removing it. Reported-by:
Feng Tang <feng.tang@intel.com> Signed-off-by:
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Andrey Konovalov authored
This patch adds kcov_remote_start/stop() callbacks around the urb complete() callback that is executed in softirq context when dummy_hcd is in use. As the result, kcov can be used to collect coverage from those callbacks, which is used to facilitate coverage-guided fuzzing with syzkaller. Signed-off-by:
Andrey Konovalov <andreyknvl@google.com> Signed-off-by:
Dmitry Vyukov <dvyukov@google.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Marco Elver <elver@google.com> Link: http://lkml.kernel.org/r/4520671eeb604adbc2432c248b0c07fbaa5519ef.1585233617.git.andreyknvl@google.com Link: http://lkml.kernel.org/r/2821d497ac1cdc0efb5e00df30271e4a67fc8009.1584655448.git.andreyknvl@google.comSigned-off-by:
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