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f3837ab7 |
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03-Feb-2023 |
Ira Weiny <ira.weiny@intel.com> |
highmem: Enhance is_kmap_addr() to check kmap_local_page() mappings is_kmap_addr() is only looking at the kmap() address range which may cause check_heap_object() to miss checking an overflow on a kmap_local_page() page. Add a check for the kmap_local_page() address range to is_kmap_addr(). Cc: Matthew Wilcox <willy@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ira Weiny <ira.weiny@intel.com> Acked-by: Andrew Morton <akpm@linux-foudation.org> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
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88d7b120 |
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26-Jan-2023 |
Matthew Wilcox (Oracle) <willy@infradead.org> |
highmem: round down the address passed to kunmap_flush_on_unmap() We already round down the address in kunmap_local_indexed() which is the other implementation of __kunmap_local(). The only implementation of kunmap_flush_on_unmap() is PA-RISC which is expecting a page-aligned address. This may be causing PA-RISC to be flushing the wrong addresses currently. Link: https://lkml.kernel.org/r/20230126200727.1680362-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Fixes: 298fa1ad5571 ("highmem: Provide generic variant of kmap_atomic*") Reviewed-by: Ira Weiny <ira.weiny@intel.com> Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Helge Deller <deller@gmx.de> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: David Sterba <dsterba@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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39ade048 |
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06-Jul-2022 |
Fabio M. De Francesco <fmdefrancesco@gmail.com> |
highmem: Make __kunmap_{local,atomic}() take const void pointer __kunmap_ {local,atomic}() currently take pointers to void. However, this is semantically incorrect, since these functions do not change the memory their arguments point to. Therefore, make this semantics explicit by modifying the __kunmap_{local,atomic}() prototypes to take pointers to const void. As a side effect, compilers may produce more efficient code. Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Helge Deller <deller@gmx.de> # parisc Suggested-by: David Sterba <dsterba@suse.cz> Suggested-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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e7392b4e |
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13-May-2022 |
Fabio M. De Francesco <fmdefrancesco@gmail.com> |
mm/highmem: fix kernel-doc warnings in highmem*.h Patch series "Extend and reorganize Highmem's documentation", v4. This series has the purpose to extend and reorganize Highmem's documentation. This is a work in progress because some information should still be moved from highmem.rst to highmem.h and highmem-internal.h. Specifically I'm talking about moving the "how to" information to the relevant headers, as it as been suggested by Ira Weiny (Intel). Also, this is a work in progress because some kdocs in highmem.h and highmem-internal.h should be improved. This patch (of 4): `scripts/kernel-doc -v -none include/linux/highmem*` reports the following warnings: include/linux/highmem.h:160: warning: expecting prototype for kunmap_atomic(). Prototype was for nr_free_highpages() instead include/linux/highmem.h:204: warning: No description found for return value of 'alloc_zeroed_user_highpage_movable' include/linux/highmem-internal.h:256: warning: Function parameter or member '__addr' not described in 'kunmap_atomic' include/linux/highmem-internal.h:256: warning: Excess function parameter 'addr' description in 'kunmap_atomic' Fix these warnings by (1) moving the kernel-doc comments from highmem.h to highmem-internal.h (which is the file were the kunmap_atomic() macro is actually defined), (2) extending and merging it with the comment which was already in highmem-internal.h, and (3) using correct parameter names (4) correcting a few technical inaccuracies in comments, and (5) adding a deprecation notice in kunmap_atomic() for consistency with kmap_atomic(). Link: https://lkml.kernel.org/r/20220428212455.892-1-fmdefrancesco@gmail.com Link: https://lkml.kernel.org/r/20220428212455.892-2-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Peter Collingbourne <pcc@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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4e140f59 |
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10-Jan-2022 |
Matthew Wilcox (Oracle) <willy@infradead.org> |
mm/usercopy: Check kmap addresses properly If you are copying to an address in the kmap region, you may not copy across a page boundary, no matter what the size of the underlying allocation. You can't kmap() a slab page because slab pages always come from low memory. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220110231530.665970-2-willy@infradead.org
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d7ca25c5 |
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22-Mar-2022 |
Ira Weiny <ira.weiny@intel.com> |
highmem: document kunmap_local() Some users of kmap() add an offset to the kmap() address to be used during the mapping. When converting to kmap_local_page() the base address does not need to be stored because any address within the page can be used in kunmap_local(). However, this was not clear from the documentation and cause some questions.[1] Document that any address in the page can be used in kunmap_local() to clarify this for future users. [1] https://lore.kernel.org/lkml/20211213154543.GM3538886@iweiny-DESK2.sc.intel.com/ [ira.weiny@intel.com: updates per Christoph] Link: https://lkml.kernel.org/r/20220124182138.816693-1-ira.weiny@intel.com Link: https://lkml.kernel.org/r/20220124013045.806718-1-ira.weiny@intel.com Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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53c36de0 |
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30-Dec-2020 |
Matthew Wilcox (Oracle) <willy@infradead.org> |
mm: Add kmap_local_folio() This allows us to map a portion of a folio. Callers can only expect to access up to the next page boundary. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Vlastimil Babka <vbabka@suse.cz>
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51386120 |
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07-Sep-2021 |
Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
highmem: don't disable preemption on RT in kmap_atomic() kmap_atomic() disables preemption and pagefaults for historical reasons. The conversion to kmap_local(), which only disables migration, cannot be done wholesale because quite some call sites need to be updated to accommodate with the changed semantics. On PREEMPT_RT enabled kernels the kmap_atomic() semantics are problematic due to the implicit disabling of preemption which makes it impossible to acquire 'sleeping' spinlocks within the kmap atomic sections. PREEMPT_RT replaces the preempt_disable() with a migrate_disable() for more than a decade. It could be argued that this is a justification to do this unconditionally, but PREEMPT_RT covers only a limited number of architectures and it disables some functionality which limits the coverage further. Limit the replacement to PREEMPT_RT for now. Link: https://lkml.kernel.org/r/20210810091116.pocdmaatdcogvdso@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a0cd7a7c |
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24-Feb-2021 |
David Hildenbrand <david@redhat.com> |
mm: simplify free_highmem_page() and free_reserved_page() adjust_managed_page_count() as called by free_reserved_page() properly handles pages in a highmem zone, so we can reuse it for free_highmem_page(). We can now get rid of totalhigh_pages_inc() and simplify free_reserved_page(). Link: https://lkml.kernel.org/r/20210126182113.19892-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f3ba3c71 |
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18-Nov-2020 |
Thomas Gleixner <tglx@linutronix.de> |
mm/highmem: Provide kmap_local* Now that the kmap atomic index is stored in task struct provide a preemptible variant. On context switch the maps of an outgoing task are removed and the map of the incoming task are restored. That's obviously slow, but highmem is slow anyway. The kmap_local.*() functions can be invoked from both preemptible and atomic context. kmap local sections disable migration to keep the resulting virtual mapping address correct, but disable neither pagefaults nor preemption. A wholesale conversion of kmap_atomic to be fully preemptible is not possible because some of the usage sites might rely on the preemption disable for serialization or on the implicit pagefault disable. Needs to be done on a case by case basis. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201118204007.468533059@linutronix.de
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5fbda3ec |
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18-Nov-2020 |
Thomas Gleixner <tglx@linutronix.de> |
sched: highmem: Store local kmaps in task struct Instead of storing the map per CPU provide and use per task storage. That prepares for local kmaps which are preemptible. The context switch code is preparatory and not yet in use because kmap_atomic() runs with preemption disabled. Will be made usable in the next step. The context switch logic is safe even when an interrupt happens after clearing or before restoring the kmaps. The kmap index in task struct is not modified so any nesting kmap in an interrupt will use unused indices and on return the counter is the same as before. Also add an assert into the return to user space code. Going back to user space with an active kmap local is a nono. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20201118204007.372935758@linutronix.de
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13f876ba |
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03-Nov-2020 |
Thomas Gleixner <tglx@linutronix.de> |
highmem: High implementation details and document API Move the gory details of kmap & al into a private header and only document the interfaces which are usable by drivers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lore.kernel.org/r/20201103095858.827582066@linutronix.de
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