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path: root/include/uapi/asm-generic/hugetlb_encode.h
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2022-10-04hugetlb_encode.h: fix undefined behaviour (34 << 26)Matthias Goergens1-13/+13
Left-shifting past the size of your datatype is undefined behaviour in C. The literal 34 gets the type `int`, and that one is not big enough to be left shifted by 26 bits. An `unsigned` is long enough (on any machine that has at least 32 bits for their ints.) For uniformity, we mark all the literals as unsigned. But it's only really needed for HUGETLB_FLAG_ENCODE_16GB. Thanks to Randy Dunlap for an initial review and suggestion. Link: https://lkml.kernel.org/r/20220905031904.150925-1-matthias.goergens@gmail.com Signed-off-by: Matthias Goergens <matthias.goergens@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2020-09-15powerpc/8xx: Support 16k hugepages with 4k pagesChristophe Leroy1-0/+1
The 8xx has 4 page sizes: 4k, 16k, 512k and 8M 4k and 16k can be selected at build time as standard page sizes, and 512k and 8M are hugepages. When 4k standard pages are selected, 16k pages are not available. Allow 16k pages as hugepages when 4k pages are used. To allow that, implement arch_make_huge_pte() which receives the necessary arguments to allow setting the PTE in accordance with the page size: - 512 k pages must have _PAGE_HUGE and _PAGE_SPS. They are set by pte_mkhuge(). arch_make_huge_pte() does nothing. - 16 k pages must have only _PAGE_SPS. arch_make_huge_pte() clears _PAGE_HUGE. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/a518abc29266a708dfbccc8fce9ae6694fe4c2c6.1598862623.git.christophe.leroy@csgroup.eu
2018-10-06mm/hugetlb: add mmap() encodings for 32MB and 512MB page sizesAnshuman Khandual1-0/+2
ARM64 architecture also supports 32MB and 512MB HugeTLB page sizes. This just adds mmap() system call argument encoding for them. Link: http://lkml.kernel.org/r/1537841300-6979-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Punit Agrawal <punit.agrawal@arm.com> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-07mm: hugetlb: define system call hugetlb size encodings in single fileMike Kravetz1-0/+34
Patch series "Consolidate system call hugetlb page size encodings". These patches are the result of discussions in https://lkml.org/lkml/2017/3/8/548. The following changes are made in the patch set: 1) Put all the log2 encoded huge page size definitions in a common header file. The idea is have a set of definitions that can be use as the basis for system call specific definitions such as MAP_HUGE_* and SHM_HUGE_*. 2) Remove MAP_HUGE_* definitions in arch specific files. All these definitions are the same. Consolidate all definitions in the primary user header file (uapi/linux/mman.h). 3) Remove SHM_HUGE_* definitions intended for user space from kernel header file, and add to user (uapi/linux/shm.h) header file. Add definitions for all known huge page size encodings as in mmap. This patch (of 3): If hugetlb pages are requested in mmap or shmget system calls, a huge page size other than default can be requested. This is accomplished by encoding the log2 of the huge page size in the upper bits of the flag argument. asm-generic and arch specific headers all define the same values for these encodings. Put common definitions in a single header file. The primary uapi header files for mmap and shm will use these definitions as a basis for definitions specific to those system calls. Link: http://lkml.kernel.org/r/1501527386-10736-2-git-send-email-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>