starfive-tech/linux.git/Documentation/x86, branch rt-linux-release

Merge tag 'docs-5.15-2' of git://git.lwn.net/linux

2021-09-08T23:28:14+00:00

Pull more documentation updates from Jonathan Corbet: "Another collection of documentation patches, mostly fixes but also includes another set of traditional Chinese translations" * tag 'docs-5.15-2' of git://git.lwn.net/linux: docs: pdfdocs: Fix typo in CJK-language specific font settings docs: kernel-hacking: Remove inappropriate text docs/zh_TW: add translations for zh_TW/filesystems docs/zh_TW: add translations for zh_TW/cpu-freq docs/zh_TW: add translations for zh_TW/arm64 docs/zh_CN: Modify the translator tag and fix the wrong word Documentation/features/vm: correct huge-vmap APIs Documentation: block: blk-mq: Fix small typo in multi-queue docs Documentation: in_irq() cleanup Documentation: arm: marvell: Add 88F6825 model into list Documentation/process/maintainer-pgp-guide: Replace broken link to PGP path finder Documentation: locking: fix references Documentation: Update details of The Linux Kernel Module Programming Guide docs: x86: Remove obsolete information about x86_64 vmalloc() faulting Documentation/process/applying-patches: Activate linux-next man hyperlink

docs: x86: Remove obsolete information about x86_64 vmalloc() faulting

2021-08-20T17:14:11+00:00

x86_64 vmalloc() mappings are no longer "synchronized" among page tables via faulting since commit 6eb82f994026 ("x86/mm: Pre-allocate P4D/PUD pages for vmalloc area"), since the corresponding P4D or PUD pages are now preallocated at boot, by preallocate_vmalloc_pages(). Drop the "lazily synchronized" description for less confusion. While this file is x86_64-specific, it is worth noting that things are different for x86_32, where vmalloc()-related changes to `init_mm.pgd` are synchronized to all page tables in the system during runtime, via arch_sync_kernel_mappings(). Unfortunately, this synchronization is subject to race condition, which is further handled via faulting, see vmalloc_fault(). See commit 4819e15f740e ("x86/mm/32: Bring back vmalloc faulting on x86_32") for more details. Reviewed-by: Muchun Song Signed-off-by: Peilin Ye Reviewed-by: Joerg Roedel Link: https://lore.kernel.org/r/20210818220123.2623-1-yepeilin.cs@gmail.com Signed-off-by: Jonathan Corbet

x86/reboot: Document how to override DMI platform quirks

2021-08-12T10:06:58+00:00

commit 5955633e91bf ("x86/reboot: Skip DMI checks if reboot set by user") made it so that it's not required to recompile the kernel in order to bypass broken reboot quirks compiled into an image: * This variable is used privately to keep track of whether or not * reboot_type is still set to its default value (i.e., reboot= hasn't * been set on the command line). This is needed so that we can * suppress DMI scanning for reboot quirks. Without it, it's * impossible to override a faulty reboot quirk without recompiling. However, at the time it was not eally documented outside the source code, and so this information isn't really available to the average user out there. The change is a little white lie and invented "reboot=default" since it is easy to remember, and documents well. The truth is that any random string that is *not* a currently accepted string will work. Since that doesn't document well for non-coders, and since it's unknown what the future additions might be, lay claim on "default" since that is exactly what it achieves. Signed-off-by: Paul Gortmaker Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210530162447.996461-3-paul.gortmaker@windriver.com

x86/reboot: Document the "reboot=pci" option

2021-08-12T10:06:58+00:00

It is mentioned in the top level non-arch specific file but it was overlooked here for x86. Signed-off-by: Paul Gortmaker Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210530162447.996461-2-paul.gortmaker@windriver.com

Merge tag 'x86-fpu-2021-07-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-07-07T18:12:01+00:00

Pull x86 fpu updates from Thomas Gleixner: "Fixes and improvements for FPU handling on x86: - Prevent sigaltstack out of bounds writes. The kernel unconditionally writes the FPU state to the alternate stack without checking whether the stack is large enough to accomodate it. Check the alternate stack size before doing so and in case it's too small force a SIGSEGV instead of silently corrupting user space data. - MINSIGSTKZ and SIGSTKSZ are constants in signal.h and have never been updated despite the fact that the FPU state which is stored on the signal stack has grown over time which causes trouble in the field when AVX512 is available on a CPU. The kernel does not expose the minimum requirements for the alternate stack size depending on the available and enabled CPU features. ARM already added an aux vector AT_MINSIGSTKSZ for the same reason. Add it to x86 as well. - A major cleanup of the x86 FPU code. The recent discoveries of XSTATE related issues unearthed quite some inconsistencies, duplicated code and other issues. The fine granular overhaul addresses this, makes the code more robust and maintainable, which allows to integrate upcoming XSTATE related features in sane ways" * tag 'x86-fpu-2021-07-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (74 commits) x86/fpu/xstate: Clear xstate header in copy_xstate_to_uabi_buf() again x86/fpu/signal: Let xrstor handle the features to init x86/fpu/signal: Handle #PF in the direct restore path x86/fpu: Return proper error codes from user access functions x86/fpu/signal: Split out the direct restore code x86/fpu/signal: Sanitize copy_user_to_fpregs_zeroing() x86/fpu/signal: Sanitize the xstate check on sigframe x86/fpu/signal: Remove the legacy alignment check x86/fpu/signal: Move initial checks into fpu__restore_sig() x86/fpu: Mark init_fpstate __ro_after_init x86/pkru: Remove xstate fiddling from write_pkru() x86/fpu: Don't store PKRU in xstate in fpu_reset_fpstate() x86/fpu: Remove PKRU handling from switch_fpu_finish() x86/fpu: Mask PKRU from kernel XRSTOR[S] operations x86/fpu: Hook up PKRU into ptrace() x86/fpu: Add PKRU storage outside of task XSAVE buffer x86/fpu: Dont restore PKRU in fpregs_restore_userspace() x86/fpu: Rename xfeatures_mask_user() to xfeatures_mask_uabi() x86/fpu: Move FXSAVE_LEAK quirk info __copy_kernel_to_fpregs() x86/fpu: Rename __fpregs_load_activate() to fpregs_restore_userregs() ...

Merge tag 'docs-5.14' of git://git.lwn.net/linux

2021-06-28T23:53:05+00:00

Pull documentation updates from Jonathan Corbet: "This was a reasonably active cycle for documentation; this includes: - Some kernel-doc cleanups. That script is still regex onslaught from hell, but it has gotten a little better. - Improvements to the checkpatch docs, which are also used by the tool itself. - A major update to the pathname lookup documentation. - Elimination of :doc: markup, since our automarkup magic can create references from filenames without all the extra noise. - The flurry of Chinese translation activity continues. Plus, of course, the usual collection of updates, typo fixes, and warning fixes" * tag 'docs-5.14' of git://git.lwn.net/linux: (115 commits) docs: path-lookup: use bare function() rather than literals docs: path-lookup: update symlink description docs: path-lookup: update get_link() ->follow_link description docs: path-lookup: update WALK_GET, WALK_PUT desc docs: path-lookup: no get_link() docs: path-lookup: update i_op->put_link and cookie description docs: path-lookup: i_op->follow_link replaced with i_op->get_link docs: path-lookup: Add macro name to symlink limit description docs: path-lookup: remove filename_mountpoint docs: path-lookup: update do_last() part docs: path-lookup: update path_mountpoint() part docs: path-lookup: update path_to_nameidata() part docs: path-lookup: update follow_managed() part docs: Makefile: Use CONFIG_SHELL not SHELL docs: Take a little noise out of the build process docs: x86: avoid using ReST :doc:`foo` markup docs: virt: kvm: s390-pv-boot.rst: avoid using ReST :doc:`foo` markup docs: userspace-api: landlock.rst: avoid using ReST :doc:`foo` markup docs: trace: ftrace.rst: avoid using ReST :doc:`foo` markup docs: trace: coresight: coresight.rst: avoid using ReST :doc:`foo` markup ...

Merge tag 'x86-splitlock-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-06-28T20:30:02+00:00

Pull x86 splitlock updates from Ingo Molnar: - Add the "ratelimit:N" parameter to the split_lock_detect= boot option, to rate-limit the generation of bus-lock exceptions. This is both easier on system resources and kinder to offending applications than the current policy of outright killing them. - Document the split-lock detection feature and its parameters. * tag 'x86-splitlock-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/x86: Add ratelimit in buslock.rst Documentation/admin-guide: Add bus lock ratelimit x86/bus_lock: Set rate limit for bus lock Documentation/x86: Add buslock.rst

docs: x86: avoid using ReST :doc:`foo` markup

2021-06-17T19:24:39+00:00

The :doc:`foo` tag is auto-generated via automarkup.py. So, use the filename at the sources, instead of :doc:`foo`. Acked-by: Peter Zijlstra (Intel) Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/17c68b5f1d72488431c77c1de9f13683fe9f536c.1623824363.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet

doc: Remove references to IBM Calgary

2021-06-10T16:19:36+00:00

The Calgary IOMMU driver has been removed in 90dc392fc445 ("x86: Remove the calgary IOMMU driver") Clean up stale docs that refer to it. Signed-off-by: Hubert Jasudowicz Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/1bd2b57dd1db53df09e520b8170ff61418805de4.1623274832.git.hubert.jasudowicz@gmail.com

x86/elf: Support a new ELF aux vector AT_MINSIGSTKSZ

2021-05-19T10:18:45+00:00

Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for use by all architectures with sigaltstack(2). Over time, the hardware state size grew, but these constants did not evolve. Today, literal use of these constants on several architectures may result in signal stack overflow, and thus user data corruption. A few years ago, the ARM team addressed this issue by establishing getauxval(AT_MINSIGSTKSZ). This enables the kernel to supply a value at runtime that is an appropriate replacement on current and future hardware. Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support added for ARM in 94b07c1f8c39 ("arm64: signal: Report signal frame size to userspace via auxv"). Also, include a documentation to describe x86-specific auxiliary vectors. Signed-off-by: Chang S. Bae Signed-off-by: Borislav Petkov Reviewed-by: Len Brown Acked-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20210518200320.17239-4-chang.seok.bae@intel.com