The EFI handover protocol was introduced on x86 to permit the boot
loader to pass a populated boot_params structure as an additional
function argument to the entry point. This allows the bootloader to
pass the base and size of a initrd image, which is more flexible
than relying on the EFI stub's file I/O routines, which can only
access the file system from which the kernel image itself was loaded
from firmware.

This approach requires a fair amount of internal knowledge regarding
the layout of the boot_params structure on the part of the boot loader,
as well as knowledge regarding the allowed placement of the initrd in
memory, and so it has been deprecated in favour of a new initrd loading
method that is based on existing UEFI protocols and best practices.

So update the x86 boot protocol documentation to clarify that the EFI
handover protocol has been deprecated, and while at it, add a note that
invoking the EFI handover protocol still requires the PE/COFF image to
be loaded properly (as opposed to simply being copied into memory).
Also, drop the code32_start header field from the list of values that
need to be provided, as this is no longer required.

Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200409130434.6736-7-ardb@kernel.org

Pull x86 cleanups from Ingo Molnar:
 "This topic tree contains more commits than usual:

   - most of it are uaccess cleanups/reorganization by Al

   - there's a bunch of prototype declaration (--Wmissing-prototypes)
     cleanups

   - misc other cleanups all around the map"

* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  x86/mm/set_memory: Fix -Wmissing-prototypes warnings
  x86/efi: Add a prototype for efi_arch_mem_reserve()
  x86/mm: Mark setup_emu2phys_nid() static
  x86/jump_label: Move 'inline' keyword placement
  x86/platform/uv: Add a missing prototype for uv_bau_message_interrupt()
  kill uaccess_try()
  x86: unsafe_put-style macro for sigmask
  x86: x32_setup_rt_frame(): consolidate uaccess areas
  x86: __setup_rt_frame(): consolidate uaccess areas
  x86: __setup_frame(): consolidate uaccess areas
  x86: setup_sigcontext(): list user_access_{begin,end}() into callers
  x86: get rid of put_user_try in __setup_rt_frame() (both 32bit and 64bit)
  x86: ia32_setup_rt_frame(): consolidate uaccess areas
  x86: ia32_setup_frame(): consolidate uaccess areas
  x86: ia32_setup_sigcontext(): lift user_access_{begin,end}() into the callers
  x86/alternatives: Mark text_poke_loc_init() static
  x86/cpu: Fix a -Wmissing-prototypes warning for init_ia32_feat_ctl()
  x86/mm: Drop pud_mknotpresent()
  x86: Replace setup_irq() by request_irq()
  x86/configs: Slightly reduce defconfigs
  ...

Pull EFI updates from Ingo Molnar:
 "The EFI changes in this cycle are much larger than usual, for two
  (positive) reasons:

   - The GRUB project is showing signs of life again, resulting in the
     introduction of the generic Linux/UEFI boot protocol, instead of
     x86 specific hacks which are increasingly difficult to maintain.
     There's hope that all future extensions will now go through that
     boot protocol.

   - Preparatory work for RISC-V EFI support.

  The main changes are:

   - Boot time GDT handling changes

   - Simplify handling of EFI properties table on arm64

   - Generic EFI stub cleanups, to improve command line handling, file
     I/O, memory allocation, etc.

   - Introduce a generic initrd loading method based on calling back
     into the firmware, instead of relying on the x86 EFI handover
     protocol or device tree.

   - Introduce a mixed mode boot method that does not rely on the x86
     EFI handover protocol either, and could potentially be adopted by
     other architectures (if another one ever surfaces where one
     execution mode is a superset of another)

   - Clean up the contents of 'struct efi', and move out everything that
     doesn't need to be stored there.

   - Incorporate support for UEFI spec v2.8A changes that permit
     firmware implementations to return EFI_UNSUPPORTED from UEFI
     runtime services at OS runtime, and expose a mask of which ones are
     supported or unsupported via a configuration table.

   - Partial fix for the lack of by-VA cache maintenance in the
     decompressor on 32-bit ARM.

   - Changes to load device firmware from EFI boot service memory
     regions

   - Various documentation updates and minor code cleanups and fixes"

* 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits)
  efi/libstub/arm: Fix spurious message that an initrd was loaded
  efi/libstub/arm64: Avoid image_base value from efi_loaded_image
  partitions/efi: Fix partition name parsing in GUID partition entry
  efi/x86: Fix cast of image argument
  efi/libstub/x86: Use ULONG_MAX as upper bound for all allocations
  efi: Fix a mistype in comments mentioning efivar_entry_iter_begin()
  efi/libstub: Avoid linking libstub/lib-ksyms.o into vmlinux
  efi/x86: Preserve %ebx correctly in efi_set_virtual_address_map()
  efi/x86: Ignore the memory attributes table on i386
  efi/x86: Don't relocate the kernel unless necessary
  efi/x86: Remove extra headroom for setup block
  efi/x86: Add kernel preferred address to PE header
  efi/x86: Decompress at start of PE image load address
  x86/boot/compressed/32: Save the output address instead of recalculating it
  efi/libstub/x86: Deal with exit() boot service returning
  x86/boot: Use unsigned comparison for addresses
  efi/x86: Avoid using code32_start
  efi/x86: Make efi32_pe_entry() more readable
  efi/x86: Respect 32-bit ABI in efi32_pe_entry()
  efi/x86: Annotate the LOADED_IMAGE_PROTOCOL_GUID with SYM_DATA
  ...

Provide more information about __ex_table sorting post link.

The exception tables and fixup tables use a commonly recurring pattern
in the kernel of storing the address of labels as date in custom ELF
sections, then finding these sections, iterating elements within them,
and possibly revisiting them or modifying the data at these addresses.

Sorting readonly arrays to minimize runtime penalties is quite clever.

Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200327000951.84071-1-ndesaulniers@google.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

finally

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Changeset 58ad30cf91f0 ("docs: fix reference to core-api/namespaces.rst")
enabled a new feature at Sphinx: it will now generate index for each
document title, plus to each chapter inside it.

There's a drawback, though: one document cannot have two sections
with the same name anymore.

A followup patch will change the logic of autosectionlabel to
avoid most creating references for every single section title,
but still we need to be able to reference the chapters inside
a document.

There are a few places where there are two chapters with the
same name. This patch renames one of the chapters, in order to
avoid symbol conflict within the same document.

PS.: as I don't speach Chinese, I had some help from a friend
(Wen Liu) at the Chinese translation for "publishing patches"
for this document:

	Documentation/translations/zh_CN/process/5.Posting.rst

Fixes: 58ad30cf91f0 ("docs: fix reference to core-api/namespaces.rst")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2bffb91e4a63d41bf5fae1c23e1e8b3bba0b8806.1584716446.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Ingo Molnar <mingo@kernel.org>

MPX was removed in commit 45fc24e89b7c ("x86/mpx: remove MPX from
arch/x86"), this removes the corresponding entry in the x86 toc.

This was suggested by a Sphinx warning.

Signed-off-by: Stephen Kitt <steve@sk2.org>
Fixes: 45fc24e89b7cc ("x86/mpx: remove MPX from arch/x86")
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Commit a24e785111a3 ("i386: paravirt boot sequence") added this flag for
use by paravirtualized environments such as Xen. However, Xen never made
use of this flag [1], and it was only ever used by lguest [2].

Commit ecda85e70277 ("x86/lguest: Remove lguest support") removed
lguest, so KEEP_SEGMENTS has lost its last user.

[1] https://lore.kernel.org/lkml/4D4B097C.5050405@goop.org
[2] https://www.mail-archive.com/lguest@lists.ozlabs.org/msg00469.html

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200202171353.3736319-2-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Pull x86 MPX removal from Dave Hansen:
 "MPX requires recompiling applications, which requires compiler
  support. Unfortunately, GCC 9.1 is expected to be be released without
  support for MPX. This means that there was only a relatively small
  window where folks could have ever used MPX. It failed to gain wide
  adoption in the industry, and Linux was the only mainstream OS to ever
  support it widely.

  Support for the feature may also disappear on future processors.

  This set completes the process that we started during the 5.4 merge
  window when the MPX prctl()s were removed. XSAVE support is left in
  place, which allows MPX-using KVM guests to continue to function"

* tag 'mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/daveh/x86-mpx:
  x86/mpx: remove MPX from arch/x86
  mm: remove arch_bprm_mm_init() hook
  x86/mpx: remove bounds exception code
  x86/mpx: remove build infrastructure
  x86/alternatives: add missing insn.h include