lwn.git/arch/x86/kernel/ldt.c, branch v6.8-rc5

arch/x86: Fix typos

2024-01-03T10:46:22+00:00

Fix typos, most reported by "codespell arch/x86". Only touches comments, no code changes. Signed-off-by: Bjorn Helgaas Signed-off-by: Ingo Molnar Reviewed-by: Randy Dunlap Link: https://lore.kernel.org/r/20240103004011.1758650-1-helgaas@kernel.org

x86: allow get_locked_pte() to fail

2023-06-19T23:19:10+00:00

In rare transient cases, not yet made possible, pte_offset_map() and pte_offset_map_lock() may not find a page table: handle appropriately. Link: https://lkml.kernel.org/r/b7fa8547-4f28-ec82-9893-1b2eb58e40b4@google.com Signed-off-by: Hugh Dickins Cc: Alexander Gordeev Cc: Alexandre Ghiti Cc: Aneesh Kumar K.V Cc: Catalin Marinas Cc: Christian Borntraeger Cc: Chris Zankel Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: "David S. Miller" Cc: Geert Uytterhoeven Cc: Greg Ungerer Cc: Heiko Carstens Cc: Helge Deller Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: John David Anglin Cc: John Paul Adrian Glaubitz Cc: Kirill A. Shutemov Cc: Matthew Wilcox (Oracle) Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Cc: Palmer Dabbelt Cc: Peter Zijlstra Cc: Qi Zheng Cc: Russell King Cc: Suren Baghdasaryan Cc: Thomas Bogendoerfer Cc: Thomas Gleixner Cc: Will Deacon Signed-off-by: Andrew Morton

memcg: enable accounting for ldt_struct objects

2021-09-03T16:58:13+00:00

Each task can request own LDT and force the kernel to allocate up to 64Kb memory per-mm. There are legitimate workloads with hundreds of processes and there can be hundreds of workloads running on large machines. The unaccounted memory can cause isolation issues between the workloads particularly on highly utilized machines. It makes sense to account for this objects to restrict the host's memory consumption from inside the memcg-limited container. Link: https://lkml.kernel.org/r/38010594-50fe-c06d-7cb0-d1f77ca422f3@virtuozzo.com Signed-off-by: Vasily Averin Acked-by: Borislav Petkov Reviewed-by: Shakeel Butt Cc: Alexander Viro Cc: Alexey Dobriyan Cc: Andrei Vagin Cc: Borislav Petkov Cc: Christian Brauner Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: "Eric W. Biederman" Cc: Greg Kroah-Hartman Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: "J. Bruce Fields" Cc: Jeff Layton Cc: Jens Axboe Cc: Jiri Slaby Cc: Johannes Weiner Cc: Kirill Tkhai Cc: Michal Hocko Cc: Oleg Nesterov Cc: Roman Gushchin Cc: Serge Hallyn Cc: Tejun Heo Cc: Thomas Gleixner Cc: Vladimir Davydov Cc: Yutian Yang Cc: Zefan Li Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

x86/ldt: Use tlb_gather_mmu_fullmm() when freeing LDT page-tables

2021-01-29T19:02:29+00:00

free_ldt_pgtables() uses the MMU gather API for batching TLB flushes over the call to free_pgd_range(). However, tlb_gather_mmu() expects to operate on user addresses and so passing LDT_{BASE,END}_ADDR will confuse the range setting logic in __tlb_adjust_range(), causing the gather to identify a range starting at TASK_SIZE. Such a large range will be converted into a 'fullmm' flush by the low-level invalidation code, so change the caller to invoke tlb_gather_mmu_fullmm() directly. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Yu Zhao Acked-by: Peter Zijlstra (Intel) Acked-by: Linus Torvalds Link: https://lkml.kernel.org/r/20210127235347.1402-7-will@kernel.org

tlb: mmu_gather: Remove start/end arguments from tlb_gather_mmu()

2021-01-29T19:02:29+00:00

The 'start' and 'end' arguments to tlb_gather_mmu() are no longer needed now that there is a separate function for 'fullmm' flushing. Remove the unused arguments and update all callers. Suggested-by: Linus Torvalds Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Yu Zhao Acked-by: Peter Zijlstra (Intel) Acked-by: Linus Torvalds Link: https://lore.kernel.org/r/CAHk-=wjQWa14_4UpfDf=fiineNP+RH74kZeDMo_f1D35xNzq9w@mail.gmail.com

tlb: mmu_gather: Remove unused start/end arguments from tlb_finish_mmu()

2021-01-29T19:02:28+00:00

Since commit 7a30df49f63a ("mm: mmu_gather: remove __tlb_reset_range() for force flush"), the 'start' and 'end' arguments to tlb_finish_mmu() are no longer used, since we flush the whole mm in case of a nested invalidation. Remove the unused arguments and update all callers. Signed-off-by: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Yu Zhao Acked-by: Peter Zijlstra (Intel) Acked-by: Linus Torvalds Link: https://lkml.kernel.org/r/20210127235347.1402-3-will@kernel.org

x86/ldt: use "pr_info_once()" instead of open-coding it badly

2020-07-05T19:50:20+00:00

Using a mutex for "print this warning only once" is so overdesigned as to be actively offensive to my sensitive stomach. Just use "pr_info_once()" that already does this, although in a (harmlessly) racy manner that can in theory cause the message to be printed twice if more than one CPU races on that "is this the first time" test. [ If somebody really cares about that harmless data race (which sounds very unlikely indeed), that person can trivially fix printk_once() by using a simple atomic access, preferably with an optimistic non-atomic test first before even bothering to treat the pointless "make sure it is _really_ just once" case. A mutex is most definitely never the right primitive to use for something like this. ] Yes, this is a small and meaningless detail in a code path that hardly matters. But let's keep some code quality standards here, and not accept outrageously bad code. Link: https://lore.kernel.org/lkml/CAHk-=wgV9toS7GU3KmNpj8hCS9SeF+A0voHS8F275_mgLhL4Lw@mail.gmail.com/ Cc: Andy Lutomirski Cc: Thomas Gleixner Cc: Peter Zijlstra (Intel) Signed-off-by: Linus Torvalds

x86/ldt: Disable 16-bit segments on Xen PV

2020-07-04T17:47:26+00:00

Xen PV doesn't implement ESPFIX64, so they don't work right. Disable them. Also print a warning the first time anyone tries to use a 16-bit segment on a Xen PV guest that would otherwise allow it to help people diagnose this change in behavior. This gets us closer to having all x86 selftests pass on Xen PV. Signed-off-by: Andy Lutomirski Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/92b2975459dfe5929ecf34c3896ad920bd9e3f2d.1593795633.git.luto@kernel.org

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Daniel Jordan Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds

x86: Remove unneeded includes

2020-03-21T15:03:25+00:00

Clean up includes of and in Signed-off-by: Brian Gerst Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200313195144.164260-19-brgerst@gmail.com