linux-stable.git/arch/x86/include/asm/setup.h, branch linux-5.4.y

x86/mm: Fix RESERVE_BRK() for older binutils

2023-11-08T10:23:39+00:00

commit e32683c6f7d22ba624e0bfc58b02cf3348bdca63 upstream.

With binutils 2.26, RESERVE_BRK() causes a build failure:

/tmp/ccnGOKZ5.s: Assembler messages:
/tmp/ccnGOKZ5.s:98: Error: missing ')'
/tmp/ccnGOKZ5.s:98: Error: missing ')'
/tmp/ccnGOKZ5.s:98: Error: missing ')'
/tmp/ccnGOKZ5.s:98: Error: junk at end of line, first unrecognized
character is `U'

The problem is this line:

RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE)

Specifically, the INIT_PGT_BUF_SIZE macro which (via PAGE_SIZE's use
_AC()) has a "1UL", which makes older versions of the assembler unhappy.
Unfortunately the _AC() macro doesn't work for inline asm.

Inline asm was only needed here to convince the toolchain to add the
STT_NOBITS flag. However, if a C variable is placed in a section whose
name is prefixed with ".bss", GCC and Clang automatically set
STT_NOBITS. In fact, ".bss..page_aligned" already relies on this trick.

So fix the build failure (and simplify the macro) by allocating the
variable in C.

Also, add NOLOAD to the ".brk" output section clause in the linker
script. This is a failsafe in case the ".bss" prefix magic trick ever
stops working somehow. If there's a section type mismatch, the GNU
linker will force the ".brk" output section to be STT_NOBITS. The LLVM
linker will fail with a "section type mismatch" error.

Note this also changes the name of the variable from .brk.##name to
__brk_##name. The variable names aren't actually used anywhere, so it's
harmless.

Fixes: a1e2c031ec39 ("x86/mm: Simplify RESERVE_BRK()")
Reported-by: Joe Damato
Reported-by: Byungchul Park
Signed-off-by: Josh Poimboeuf
Signed-off-by: Peter Zijlstra (Intel)
Tested-by: Joe Damato
Link: https://lore.kernel.org/r/22d07a44c80d8e8e1e82b9a806ddc8c6bbb2606e.1654759036.git.jpoimboe@kernel.org
[nathan: Fix conflict due to lack of 360db4ace311 and resolve silent
conflict with 360db4ace3117]
Signed-off-by: Nathan Chancellor
Signed-off-by: Greg Kroah-Hartman

x86/mm: Simplify RESERVE_BRK()

2023-11-08T10:23:38+00:00

commit a1e2c031ec3949b8c039b739c0b5bf9c30007b00 upstream.

RESERVE_BRK() reserves data in the .brk_reservation section.  The data
is initialized to zero, like BSS, so the macro specifies 'nobits' to
prevent the data from taking up space in the vmlinux binary.  The only
way to get the compiler to do that (without putting the variable in .bss
proper) is to use inline asm.

The macro also has a hack which encloses the inline asm in a discarded
function, which allows the size to be passed (global inline asm doesn't
allow inputs).

Remove the need for the discarded function hack by just stringifying the
size rather than supplying it as an input to the inline asm.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Borislav Petkov 
Reviewed-by: Borislav Petkov 
Link: https://lore.kernel.org/r/20220506121631.133110232@infradead.org
[nathan: Fix conflict due to lack of 2b6ff7dea670 and 33def8498fdd]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

x86/kernel: Fix more -Wmissing-prototypes warnings

2018-12-08T11:24:35+00:00

... with the goal of eventually enabling -Wmissing-prototypes by
default. At least on x86.

Make functions static where possible, otherwise add prototypes or make
them visible through includes.

asm/trace/ changes courtesy of Steven Rostedt .

Signed-off-by: Borislav Petkov 
Reviewed-by: Masami Hiramatsu 
Reviewed-by: Ingo Molnar 
Acked-by: Rafael J. Wysocki  # ACPI + cpufreq bits
Cc: Andrew Banman 
Cc: Dimitri Sivanich 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Masami Hiramatsu 
Cc: Mike Travis 
Cc: "Steven Rostedt (VMware)" 
Cc: Thomas Gleixner 
Cc: Yi Wang 
Cc: linux-acpi@vger.kernel.org

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

treewide: Consolidate Apple DMI checks

2017-08-03T21:26:22+00:00

We're about to amend ACPI bus scan with DMI checks whether we're running
on a Mac to support Apple device properties in AML.  The DMI checks are
performed for every single device, adding overhead for everything x86
that isn't Apple, which is the majority.  Rafael and Andy therefore
request to perform the DMI match only once and cache the result.

Outside of ACPI various other Apple DMI checks exist and it seems
reasonable to use the cached value there as well.  Rafael, Andy and
Darren suggest performing the DMI check in arch code and making it
available with a header in include/linux/platform_data/x86/.

To this end, add early_platform_quirks() to arch/x86/kernel/quirks.c
to perform the DMI check and invoke it from setup_arch().  Switch over
all existing Apple DMI checks, thereby fixing two deficiencies:

* They are now #defined to false on non-x86 arches and can thus be
  optimized away if they're located in cross-arch code.

* Some of them only match "Apple Inc." but not "Apple Computer, Inc.",
  which is used by BIOSes released between January 2006 (when the first
  x86 Macs started shipping) and January 2007 (when the company name
  changed upon introduction of the iPhone).

Suggested-by: Andy Shevchenko 
Suggested-by: Rafael J. Wysocki 
Suggested-by: Darren Hart 
Signed-off-by: Lukas Wunner 
Acked-by: Mika Westerberg 
Signed-off-by: Rafael J. Wysocki

x86/time: Make setup_default_timer_irq() static

2017-06-13T06:42:09+00:00

This function isn't used outside of time.c, so let's mark it static.

Signed-off-by: Dou Liyang 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/1497321029-29049-1-git-send-email-douly.fnst@cn.fujitsu.com
Signed-off-by: Ingo Molnar

x86/asm: Stop depending on ptrace.h in alternative.h

2016-04-29T09:56:40+00:00

alternative.h pulls in ptrace.h, which means that alternatives can't
be used in anything referenced from ptrace.h, which is a mess.

Break the dependency by pulling text patching helpers into their own
header.

Signed-off-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/99b93b13f2c9eb671f5c98bba4c2cbdc061293a2.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86: kaslr: fix build due to missing ALIGN definition

2015-04-29T19:54:54+00:00

Fengguang's bot reported that 4545c898 ("x86: introduce kaslr_offset()") broke
randconfig build

   In file included from arch/x86/xen/vga.c:5:0:
   arch/x86/include/asm/setup.h: In function 'kaslr_offset':
>> arch/x86/include/asm/setup.h:77:2: error: implicit declaration of function 'ALIGN' [-Werror=implicit-function-declaration]
     return (unsigned long)&_text - __START_KERNEL;
     ^
Fix that by making setup.h self-sufficient by explicitly including
linux/kernel.h, which is needed for ALIGN() (which is what __START_KERNEL
contains in its expansion).

Reported-by: fengguang.wu@intel.com
Signed-off-by: Jiri Kosina

x86: introduce kaslr_offset()

2015-04-29T14:51:33+00:00

Offset that has been chosen for kaslr during kernel decompression can be
easily computed as a difference between _text and __START_KERNEL. We are
already making use of this in dump_kernel_offset() notifier and in
arch_crash_save_vmcoreinfo().

Introduce kaslr_offset() that makes this computation instead of hard-coding
it, so that other kernel code (such as live patching) can make use of it.
Also convert existing users to make use of it.

This patch is equivalent transofrmation without any effects on the resulting
code:

	$ diff -u vmlinux.old.asm vmlinux.new.asm
	--- vmlinux.old.asm     2015-04-28 17:55:19.520983368 +0200
	+++ vmlinux.new.asm     2015-04-28 17:55:24.141206072 +0200
	@@ -1,5 +1,5 @@

	-vmlinux.old:     file format elf64-x86-64
	+vmlinux.new:     file format elf64-x86-64

	Disassembly of section .text:
	$

Acked-by: Borislav Petkov 
Signed-off-by: Jiri Kosina

x86/mm/KASLR: Propagate KASLR status to kernel proper

2015-04-03T13:26:15+00:00

Commit:

  e2b32e678513 ("x86, kaslr: randomize module base load address")

made module base address randomization unconditional and didn't regard
disabled KKASLR due to CONFIG_HIBERNATION and command line option
"nokaslr". For more info see (now reverted) commit:

  f47233c2d34f ("x86/mm/ASLR: Propagate base load address calculation")

In order to propagate KASLR status to kernel proper, we need a single bit
in boot_params.hdr.loadflags and we've chosen bit 1 thus leaving the
top-down allocated bits for bits supposed to be used by the bootloader.

Originally-From: Jiri Kosina 
Suggested-by: H. Peter Anvin 
Signed-off-by: Borislav Petkov 
Cc: Kees Cook 
Signed-off-by: Ingo Molnar