linux-toradex.git/arch/x86/include/asm/proto.h, branch v5.18

x86/arch_prctl: Add controls for dynamic XSTATE components

2021-10-26T08:18:09+00:00

Dynamically enabled XSTATE features are by default disabled for all
processes. A process has to request permission to use such a feature.

To support this implement a architecture specific prctl() with the options:

   - ARCH_GET_XCOMP_SUPP

     Copies the supported feature bitmap into the user space provided
     u64 storage. The pointer is handed in via arg2

   - ARCH_GET_XCOMP_PERM

     Copies the process wide permitted feature bitmap into the user space
     provided u64 storage. The pointer is handed in via arg2

   - ARCH_REQ_XCOMP_PERM

     Request permission for a feature set. A feature set can be mapped to a
     facility, e.g. AMX, and can require one or more XSTATE components to
     be enabled.

     The feature argument is the number of the highest XSTATE component
     which is required for a facility to work.

     The request argument is not a user supplied bitmap because that makes
     filtering harder (think seccomp) and even impossible because to
     support 32bit tasks the argument would have to be a pointer.

The permission mechanism works this way:

   Task asks for permission for a facility and kernel checks whether that's
   supported. If supported it does:

     1) Check whether permission has already been granted

     2) Compute the size of the required kernel and user space buffer
        (sigframe) size.

     3) Validate that no task has a sigaltstack installed
        which is smaller than the resulting sigframe size

     4) Add the requested feature bit(s) to the permission bitmap of
        current->group_leader->fpu and store the sizes in the group
        leaders fpu struct as well.

If that is successful then the feature is still not enabled for any of the
tasks. The first usage of a related instruction will result in a #NM
trap. The trap handler validates the permission bit of the tasks group
leader and if permitted it installs a larger kernel buffer and transfers
the permission and size info to the new fpstate container which makes all
the FPU functions which require per task information aware of the extended
feature set.

  [ tglx: Adopted to new base code, added missing serialization,
          massaged namings, comments and changelog ]

Signed-off-by: Chang S. Bae 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Chang S. Bae 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20211021225527.10184-7-chang.seok.bae@intel.com

x86/asm: Ensure asm/proto.h can be included stand-alone

2021-04-12T11:12:46+00:00

Fix:

  ../arch/x86/include/asm/proto.h:14:30: warning: ‘struct task_struct’ declared \
    inside parameter list will not be visible outside of this definition or declaration
  long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2);
                               ^~~~~~~~~~~

  .../arch/x86/include/asm/proto.h:40:34: warning: ‘struct task_struct’ declared \
    inside parameter list will not be visible outside of this definition or declaration
   long do_arch_prctl_common(struct task_struct *task, int option,
                                    ^~~~~~~~~~~

if linux/sched.h hasn't be included previously. This fixes a build error
when this header is used outside of the kernel tree.

 [ bp: Massage commit message. ]

Signed-off-by: Jan Kiszka 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/b76b4be3-cf66-f6b2-9a6c-3e7ef54f9845@web.de

x86/sev-es: Introduce ip_within_syscall_gap() helper

2021-03-08T13:22:17+00:00

Introduce a helper to check whether an exception came from the syscall
gap and use it in the SEV-ES code. Extend the check to also cover the
compatibility SYSCALL entry path.

Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler")
Signed-off-by: Joerg Roedel 
Signed-off-by: Borislav Petkov 
Cc: stable@vger.kernel.org # 5.10+
Link: https://lkml.kernel.org/r/20210303141716.29223-2-joro@8bytes.org

x86/entry/64: Add entry code for #VC handler

2020-09-09T09:33:19+00:00

The #VC handler needs special entry code because:

	1. It runs on an IST stack

	2. It needs to be able to handle nested #VC exceptions

To make this work, the entry code is implemented to pretend it doesn't
use an IST stack. When entered from user-mode or early SYSCALL entry
path it switches to the task stack. If entered from kernel-mode it tries
to switch back to the previous stack in the IRET frame.

The stack found in the IRET frame is validated first, and if it is not
safe to use it for the #VC handler, the code will switch to a
fall-back stack (the #VC2 IST stack). From there, it can cause nested
exceptions again.

Signed-off-by: Joerg Roedel 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/20200907131613.12703-46-joro@8bytes.org

x86/xen: remove 32-bit Xen PV guest support

2020-08-11T06:26:48+00:00

Xen is requiring 64-bit machines today and since Xen 4.14 it can be
built without 32-bit PV guest support. There is no need to carry the
burden of 32-bit PV guest support in the kernel any longer, as new
guests can be either HVM or PVH, or they can use a 64 bit kernel.

Remove the 32-bit Xen PV support from the kernel.

Signed-off-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
Signed-off-by: Juergen Gross

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart 
Reviewed-by: Philippe Ombredanne 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86/xen: Get rid of paravirt op adjust_exception_frame

2017-08-31T19:35:10+00:00

When running as Xen pv-guest the exception frame on the stack contains
%r11 and %rcx additional to the other data pushed by the processor.

Instead of having a paravirt op being called for each exception type
prepend the Xen specific code to each exception entry. When running as
Xen pv-guest just use the exception entry with prepended instructions,
otherwise use the entry without the Xen specific code.

[ tglx: Merged through tip to avoid ugly merge conflict ]

Signed-off-by: Juergen Gross 
Signed-off-by: Thomas Gleixner 
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/20170831174249.26853-1-jg@pfupf.net

x86/arch_prctl: Add do_arch_prctl_common()

2017-03-20T15:10:33+00:00

Add do_arch_prctl_common() to handle arch_prctls that are not specific to 64
bit mode. Call it from the syscall entry point, but not any of the other
callsites in the kernel, which all want one of the existing 64 bit only
arch_prctls.

Signed-off-by: Kyle Huey 
Cc: Grzegorz Andrejczuk 
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář 
Cc: Peter Zijlstra 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: linux-kselftest@vger.kernel.org
Cc: Nadav Amit 
Cc: Robert O'Callahan 
Cc: Richard Weinberger 
Cc: "Rafael J. Wysocki" 
Cc: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Len Brown 
Cc: Shuah Khan 
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: Jeff Dike 
Cc: Alexander Viro 
Cc: user-mode-linux-user@lists.sourceforge.net
Cc: David Matlack 
Cc: Boris Ostrovsky 
Cc: Dmitry Safonov 
Cc: linux-fsdevel@vger.kernel.org
Cc: Paolo Bonzini 
Link: http://lkml.kernel.org/r/20170320081628.18952-6-khuey@kylehuey.com
Signed-off-by: Thomas Gleixner

x86/arch_prctl/64: Rename do_arch_prctl() to do_arch_prctl_64()

2017-03-20T15:10:32+00:00

In order to introduce new arch_prctls that are not 64 bit only, rename the
existing 64 bit implementation to do_arch_prctl_64(). Also rename the
second argument of that function from 'addr' to 'arg2', because it will no
longer always be an address.

Signed-off-by: Kyle Huey 
Reviewed-by: Andy Lutomirski 
Cc: Grzegorz Andrejczuk 
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář 
Cc: Peter Zijlstra 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: linux-kselftest@vger.kernel.org
Cc: Nadav Amit 
Cc: Robert O'Callahan 
Cc: Richard Weinberger 
Cc: "Rafael J. Wysocki" 
Cc: Borislav Petkov 
Cc: Len Brown 
Cc: Shuah Khan 
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: Jeff Dike 
Cc: Alexander Viro 
Cc: user-mode-linux-user@lists.sourceforge.net
Cc: David Matlack 
Cc: Boris Ostrovsky 
Cc: Dmitry Safonov 
Cc: linux-fsdevel@vger.kernel.org
Cc: Paolo Bonzini 
Link: http://lkml.kernel.org/r/20170320081628.18952-5-khuey@kylehuey.com
Signed-off-by: Thomas Gleixner

x86/arch_prctl: Rename 'code' argument to 'option'

2017-03-20T15:10:32+00:00

The x86 specific arch_prctl() arbitrarily changed prctl's 'option' to
'code'. Before adding new options, rename it.

Signed-off-by: Kyle Huey 
Cc: Grzegorz Andrejczuk 
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář 
Cc: Peter Zijlstra 
Cc: Dave Hansen 
Cc: Andi Kleen 
Cc: linux-kselftest@vger.kernel.org
Cc: Nadav Amit 
Cc: Robert O'Callahan 
Cc: Richard Weinberger 
Cc: "Rafael J. Wysocki" 
Cc: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Len Brown 
Cc: Shuah Khan 
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: Jeff Dike 
Cc: Alexander Viro 
Cc: user-mode-linux-user@lists.sourceforge.net
Cc: David Matlack 
Cc: Boris Ostrovsky 
Cc: Dmitry Safonov 
Cc: linux-fsdevel@vger.kernel.org
Cc: Paolo Bonzini 
Link: http://lkml.kernel.org/r/20170320081628.18952-3-khuey@kylehuey.com
Signed-off-by: Thomas Gleixner