linux.git/arch/x86/include/asm/Kbuild, branch master

ring-buffer: Flush and stop persistent ring buffer on panic

2026-05-21T12:20:58+00:00

On real hardware, panic and machine reboot may not flush hardware cache
to memory. This means the persistent ring buffer, which relies on a
coherent state of memory, may not have its events written to the buffer
and they may be lost. Moreover, there may be inconsistency with the
counters which are used for validation of the integrity of the
persistent ring buffer which may cause all data to be discarded.

To avoid this issue, stop recording of the ring buffer on panic and
flush the cache of the ring buffer's memory.

Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance")
Cc: stable@vger.kernel.org
Cc: Will Deacon 
Cc: Mathieu Desnoyers 
Cc: Ian Rogers 
Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com
Signed-off-by: Masami Hiramatsu (Google) 
Acked-by: Catalin Marinas 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Steven Rostedt

x86/cpufeatures: Generate the header based on build config

2025-03-19T10:15:11+00:00

Introduce an AWK script to auto-generate the  header
with required and disabled feature masks based on 
and the current build config.

Thus for any CPU feature with a build config, e.g., X86_FRED, simply add:

  config X86_DISABLED_FEATURE_FRED
	def_bool y
	depends on !X86_FRED

to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU
feature disable flag, e.g., DISABLE_FRED.

Lastly, the generated required and disabled feature masks will be added to
their corresponding feature masks for this particular compile-time
configuration.

  [ Xin: build integration improvements ]
  [ mingo: Improved changelog and comments ]

Signed-off-by: H. Peter Anvin (Intel) 
Signed-off-by: Xin Li (Intel) 
Signed-off-by: Borislav Petkov (AMD) 
Signed-off-by: Ingo Molnar 
Reviewed-by: Nikolay Borisov 
Cc: Linus Torvalds 
Link: https://lore.kernel.org/r/20250305184725.3341760-3-xin@zytor.com

fprobe: Add fprobe_header encoding feature

2024-12-26T15:50:05+00:00

Fprobe store its data structure address and size on the fgraph return stack
by __fprobe_header. But most 64bit architecture can combine those to
one unsigned long value because 4 MSB in the kernel address are the same.
With this encoding, fprobe can consume less space on ret_stack.

This introduces asm/fprobe.h to define arch dependent encode/decode
macros. Note that since fprobe depends on CONFIG_HAVE_FUNCTION_GRAPH_FREGS,
currently only arm64, loongarch, riscv, s390 and x86 are supported.

Signed-off-by: Masami Hiramatsu (Google) 
Acked-by: Heiko Carstens  # s390
Cc: Catalin Marinas 
Cc: Alexei Starovoitov 
Cc: Florent Revest 
Cc: Martin KaFai Lau 
Cc: bpf 
Cc: Alexei Starovoitov 
Cc: Jiri Olsa 
Cc: Alan Maguire 
Cc: Mark Rutland 
Cc: Heiko Carstens 
Cc: Will Deacon 
Cc: Huacai Chen 
Cc: WANG Xuerui 
Cc: Paul Walmsley 
Cc: Palmer Dabbelt 
Cc: Albert Ou 
Cc: Vasily Gorbik 
Cc: Alexander Gordeev 
Cc: Christian Borntraeger 
Cc: Sven Schnelle 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: x86@kernel.org
Cc: "H. Peter Anvin" 
Cc: Arnd Bergmann 
Cc: Masami Hiramatsu 
Cc: Mathieu Desnoyers 
Link: https://lore.kernel.org/173519005783.391279.5307910947400277525.stgit@devnote2
Signed-off-by: Steven Rostedt (Google)

arch, mm: move definition of node_data to generic code

2024-09-04T04:15:28+00:00

Every architecture that supports NUMA defines node_data in the same way:

	struct pglist_data *node_data[MAX_NUMNODES];

No reason to keep multiple copies of this definition and its forward
declarations, especially when such forward declaration is the only thing
in include/asm/mmzone.h for many architectures.

Add definition and declaration of node_data to generic code and drop
architecture-specific versions.

Link: https://lkml.kernel.org/r/20240807064110.1003856-8-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) 
Acked-by: David Hildenbrand 
Reviewed-by: Jonathan Cameron 
Acked-by: Davidlohr Bueso 
Tested-by: Zi Yan  # for x86_64 and arm64
Tested-by: Jonathan Cameron  [arm64 + CXL via QEMU]
Acked-by: Dan Williams 
Cc: Alexander Gordeev 
Cc: Andreas Larsson 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Christophe Leroy 
Cc: Dave Hansen 
Cc: David S. Miller 
Cc: Greg Kroah-Hartman 
Cc: Heiko Carstens 
Cc: Huacai Chen 
Cc: Ingo Molnar 
Cc: Jiaxun Yang 
Cc: John Paul Adrian Glaubitz 
Cc: Jonathan Corbet 
Cc: Michael Ellerman 
Cc: Palmer Dabbelt 
Cc: Rafael J. Wysocki 
Cc: Rob Herring (Arm) 
Cc: Samuel Holland 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

x86/headers: Remove

2023-10-03T08:38:08+00:00

All *.S files under arch/x86/ have been converted to include
 instead of .

Remove .

Signed-off-by: Masahiro Yamada 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20230806145958.380314-3-masahiroy@kernel.org

x86/unwind/orc: Add ELF section with ORC version identifier

2023-06-16T15:17:42+00:00

Commits ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC
metadata") and fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in
two") changed the ORC format. Although ORC is internal to the kernel,
it's the only way for external tools to get reliable kernel stack traces
on x86-64. In particular, the drgn debugger [1] uses ORC for stack
unwinding, and these format changes broke it [2]. As the drgn
maintainer, I don't care how often or how much the kernel changes the
ORC format as long as I have a way to detect the change.

It suffices to store a version identifier in the vmlinux and kernel
module ELF files (to use when parsing ORC sections from ELF), and in
kernel memory (to use when parsing ORC from a core dump+symbol table).
Rather than hard-coding a version number that needs to be manually
bumped, Peterz suggested hashing the definitions from orc_types.h. If
there is a format change that isn't caught by this, the hashing script
can be updated.

This patch adds an .orc_header allocated ELF section containing the
20-byte hash to vmlinux and kernel modules, along with the corresponding
__start_orc_header and __stop_orc_header symbols in vmlinux.

1: https://github.com/osandov/drgn
2: https://github.com/osandov/drgn/issues/303

Fixes: ffb1b4a41016 ("x86/unwind/orc: Add 'signal' field to ORC metadata")
Fixes: fb799447ae29 ("x86,objtool: Split UNWIND_HINT_EMPTY in two")
Signed-off-by: Omar Sandoval
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Josh Poimboeuf
Link: https://lkml.kernel.org/r/aef9c8dc43915b886a8c48509a12ec1b006ca1ca.1686690801.git.osandov@osandov.com

x86/syscalls: Switch to generic syscalltbl.sh

2021-05-20T13:03:58+00:00

Many architectures duplicate similar shell scripts.

Convert x86 and UML to use scripts/syscalltbl.sh. The generic script
generates seperate headers for x86/64 and x86/x32 syscalls, while the x86
specific script coalesced them into one. Adjust the code accordingly.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Thomas Gleixner 
Link: https://lore.kernel.org/r/20210517073815.97426-3-masahiroy@kernel.org

asm-generic: make more kernel-space headers mandatory

2020-04-02T16:35:25+00:00

Change a header to mandatory-y if both of the following are met:

[1] At least one architecture (except um) specifies it as generic-y in
    arch/*/include/asm/Kbuild

[2] Every architecture (except um) either has its own implementation
    (arch/*/include/asm/*.h) or specifies it as generic-y in
    arch/*/include/asm/Kbuild

This commit was generated by the following shell script.

----------------------------------->8-----------------------------------

arches=$(cd arch; ls -1 | sed -e '/Kconfig/d' -e '/um/d')

tmpfile=$(mktemp)

grep "^mandatory-y +=" include/asm-generic/Kbuild > $tmpfile

find arch -path 'arch/*/include/asm/Kbuild' |
	xargs sed -n 's/^generic-y += \(.*\)/\1/p' | sort -u |
while read header
do
	mandatory=yes

	for arch in $arches
	do
		if ! grep -q "generic-y += $header" arch/$arch/include/asm/Kbuild &&
			! [ -f arch/$arch/include/asm/$header ]; then
			mandatory=no
			break
		fi
	done

	if [ "$mandatory" = yes ]; then
		echo "mandatory-y += $header" >> $tmpfile

		for arch in $arches
		do
			sed -i "/generic-y += $header/d" arch/$arch/include/asm/Kbuild
		done
	fi

done

sed -i '/^mandatory-y +=/d' include/asm-generic/Kbuild

LANG=C sort $tmpfile >> include/asm-generic/Kbuild

----------------------------------->8-----------------------------------

One obvious benefit is the diff stat:

 25 files changed, 52 insertions(+), 557 deletions(-)

It is tedious to list generic-y for each arch that needs it.

So, mandatory-y works like a fallback default (by just wrapping
asm-generic one) when arch does not have a specific header
implementation.

See the following commits:

def3f7cefe4e81c296090e1722a76551142c227c
a1b39bae16a62ce4aae02d958224f19316d98b24

It is tedious to convert headers one by one, so I processed by a shell
script.

Signed-off-by: Masahiro Yamada 
Signed-off-by: Andrew Morton 
Cc: Michal Simek 
Cc: Christoph Hellwig 
Cc: Arnd Bergmann 
Link: http://lkml.kernel.org/r/20200210175452.5030-1-masahiroy@kernel.org
Signed-off-by: Linus Torvalds

asm-generic: Make dma-contiguous.h a mandatory include/asm header

2020-02-04T10:38:59+00:00

dma-continuguous.h is generic for all architectures except arm32 which has
its own version.

Similar change was done for msi.h by commit a1b39bae16a6
("asm-generic: Make msi.h a mandatory include/asm header")

Suggested-by: Christoph Hellwig 
Link: https://lore.kernel.org/linux-arm-kernel/20200117080446.GA8980@lst.de/T/#m92bb56b04161057635d4142e1b3b9b6b0a70122e
Signed-off-by: Michal Simek 
Reviewed-by: Christoph Hellwig 
Acked-by: Thomas Gleixner 
Acked-by: Arnd Bergmann 
Acked-by: Paul Walmsley  # for arch/riscv

treewide: Add SPDX license identifier - Kbuild

2019-05-30T18:32:33+00:00

Add SPDX license identifiers to all Make/Kconfig files which:

 - Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

      GPL-2.0

Reported-by: Masahiro Yamada 
Signed-off-by: Greg Kroah-Hartman 
Reviewed-by: Kate Stewart 
Signed-off-by: Greg Kroah-Hartman