linux.git/Documentation/x86, branch v5.5

Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-11-26T16:40:20+00:00

Pull x86 boot updates from Ingo Molnar:
 "The main changes were:

   - Extend the boot protocol to allow future extensions without hitting
     the setup_header size limit.

   - Add quirk to devicetree systems to disable the RTC unless it's
     listed as a supported device.

   - Fix ld.lld linker pedantry"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/boot: Introduce setup_indirect
  x86/boot: Introduce kernel_info.setup_type_max
  x86/boot: Introduce kernel_info
  x86/init: Allow DT configured systems to disable RTC at boot time
  x86/realmode: Explicitly set entry point via ENTRY in linker script

x86/boot: Introduce setup_indirect

2019-11-12T15:21:15+00:00

The setup_data is a bit awkward to use for extremely large data objects,
both because the setup_data header has to be adjacent to the data object
and because it has a 32-bit length field. However, it is important that
intermediate stages of the boot process have a way to identify which
chunks of memory are occupied by kernel data. Thus introduce an uniform
way to specify such indirect data as setup_indirect struct and
SETUP_INDIRECT type.

And finally bump setup_header version in arch/x86/boot/header.S.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Acked-by: Konrad Rzeszutek Wilk 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-4-daniel.kiper@oracle.com

x86/boot: Introduce kernel_info.setup_type_max

2019-11-12T15:16:54+00:00

This field contains maximal allowed type for setup_data.

Do not bump setup_header version in arch/x86/boot/header.S because it
will be followed by additional changes coming into the Linux/x86 boot
protocol.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-3-daniel.kiper@oracle.com

x86/boot: Introduce kernel_info

2019-11-12T15:10:34+00:00

The relationships between the headers are analogous to the various data
sections:

  setup_header = .data
  boot_params/setup_data = .bss

What is missing from the above list? That's right:

  kernel_info = .rodata

We have been (ab)using .data for things that could go into .rodata or .bss for
a long time, for lack of alternatives and -- especially early on -- inertia.
Also, the BIOS stub is responsible for creating boot_params, so it isn't
available to a BIOS-based loader (setup_data is, though).

setup_header is permanently limited to 144 bytes due to the reach of the
2-byte jump field, which doubles as a length field for the structure, combined
with the size of the "hole" in struct boot_params that a protected-mode loader
or the BIOS stub has to copy it into. It is currently 119 bytes long, which
leaves us with 25 very precious bytes. This isn't something that can be fixed
without revising the boot protocol entirely, breaking backwards compatibility.

boot_params proper is limited to 4096 bytes, but can be arbitrarily extended
by adding setup_data entries. It cannot be used to communicate properties of
the kernel image, because it is .bss and has no image-provided content.

kernel_info solves this by providing an extensible place for information about
the kernel image. It is readonly, because the kernel cannot rely on a
bootloader copying its contents anywhere, but that is OK; if it becomes
necessary it can still contain data items that an enabled bootloader would be
expected to copy into a setup_data chunk.

Do not bump setup_header version in arch/x86/boot/header.S because it
will be followed by additional changes coming into the Linux/x86 boot
protocol.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-2-daniel.kiper@oracle.com

x86/speculation/taa: Add documentation for TSX Async Abort

2019-10-28T07:37:00+00:00

Add the documenation for TSX Async Abort. Include the description of
the issue, how to check the mitigation state, control the mitigation,
guidance for system administrators.

 [ bp: Add proper SPDX tags, touch ups by Josh and me. ]

Co-developed-by: Antonio Gomez Iglesias 

Signed-off-by: Pawan Gupta 
Signed-off-by: Antonio Gomez Iglesias 
Signed-off-by: Borislav Petkov 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Mark Gross 
Reviewed-by: Tony Luck 
Reviewed-by: Josh Poimboeuf

dma-mapping: fix filename references

2019-09-03T06:36:30+00:00

After commit cf65a0f6f6ff ("dma-mapping: move all DMA mapping code to
kernel/dma") some of the files are referring to outdated information,
i.e. old file names of DMA mapping sources. Fix it here.

Note, the lines with "Glue code for..." have been removed completely.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Christoph Hellwig

docs: remove extra conf.py files

2019-07-17T09:57:52+00:00

Now that the latex_documents are handled automatically, we can
remove those extra conf.py files.

Signed-off-by: Mauro Carvalho Chehab

docs: admin-guide: add a series of orphaned documents

2019-07-15T14:03:02+00:00

There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).

Move them to the admin guide.

Signed-off-by: Mauro Carvalho Chehab 
Acked-by: Alexandre Belloni 
Acked-by: Bartlomiej Zolnierkiewicz

docs: cgroup-v1: add it to the admin-guide book

2019-07-15T14:03:02+00:00

Those files belong to the admin guide, so add them.

Signed-off-by: Mauro Carvalho Chehab

docs: x86: move two x86-specific files to x86 arch dir

2019-07-15T14:03:01+00:00

Those two docs belong to the x86 architecture:

   Documentation/Intel-IOMMU.txt -> Documentation/x86/intel-iommu.rst
   Documentation/intel_txt.txt -> Documentation/x86/intel_txt.rst

Signed-off-by: Mauro Carvalho Chehab