linux-stable.git/arch/arm/Makefile, branch v6.2

ARM: 9287/1: Reduce thumb2 definition to crypto files that require it

2023-01-23T14:31:18+00:00

Commit 1d2e9b67b001 ("ARM: 9265/1: pass -march= only to compiler") added
a __thumb2__ define to ASFLAGS to avoid build errors in the crypto code,
which relies on __thumb2__ for preprocessing. Commit 59e2cf8d21e0 ("ARM:
9275/1: Drop '-mthumb' from AFLAGS_ISA") followed up on this by removing
-mthumb from AFLAGS so that __thumb2__ would not be defined when the
default target was ARMv7 or newer.

Unfortunately, the second commit's fix assumes that the toolchain
defaults to -mno-thumb / -marm, which is not the case for Debian's
arm-linux-gnueabihf target, which defaults to -mthumb:

  $ echo | arm-linux-gnueabihf-gcc -dM -E - | grep __thumb
  #define __thumb2__ 1
  #define __thumb__ 1

This target is used by several CI systems, which will still see
redefined macro warnings, despite '-mthumb' not being present in the
flags:

  : warning: "__thumb2__" redefined
  : note: this is the location of the previous definition

Remove the global AFLAGS __thumb2__ define and move it to the crypto
folder where it is required by the imported OpenSSL algorithms; the rest
of the kernel should use the internal CONFIG_THUMB2_KERNEL symbol to
know whether or not Thumb2 is being used or not. Be sure that __thumb2__
is undefined first so that there are no macro redefinition warnings.

Link: https://github.com/ClangBuiltLinux/linux/issues/1772

Reported-by: "kernelci.org bot" 
Suggested-by: Ard Biesheuvel 
Signed-off-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Tested-by: Nick Desaulniers 
Fixes: 59e2cf8d21e0 ("ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA")
Fixes: 1d2e9b67b001 ("ARM: 9265/1: pass -march= only to compiler")
Signed-off-by: Russell King (Oracle)

Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2022-12-13T23:22:14+00:00

Pull ARM updates from Russell King:

 - update unwinder to cope with module PLTs

 - enable UBSAN on ARM

 - improve kernel fault message

 - update UEFI runtime page tables dump

 - avoid clang's __aeabi_uldivmod generated in NWFPE code

 - disable FIQs on CPU shutdown paths

 - update XOR register usage

 - a number of build updates (using .arch, thread pointer, removal of
   lazy evaluation in Makefile)

 - conversion of stacktrace code to stackwalk

 - findbit assembly updates

 - hwcap feature updates for ARMv8 CPUs

 - instruction dump updates for big-endian platforms

 - support for function error injection

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits)
  ARM: 9279/1: support function error injection
  ARM: 9277/1: Make the dumped instructions are consistent with the disassembled ones
  ARM: 9276/1: Refactor dump_instr()
  ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA
  ARM: 9274/1: Add hwcap for Speculative Store Bypassing Safe
  ARM: 9273/1: Add hwcap for Speculation Barrier(SB)
  ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MM
  ARM: 9271/1: vfp: Add hwcap for FEAT_AA32BF16
  ARM: 9270/1: vfp: Add hwcap for FEAT_FHM
  ARM: 9269/1: vfp: Add hwcap for FEAT_DotProd
  ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16
  ARM: 9267/1: Define Armv8 registers in AArch32 state
  ARM: findbit: add unwinder information
  ARM: findbit: operate by words
  ARM: findbit: convert to macros
  ARM: findbit: provide more efficient ARMv7 implementation
  ARM: findbit: document ARMv5 bit offset calculation
  ARM: 9259/1: stacktrace: Convert stacktrace to generic ARCH_STACKWALK
  ARM: 9258/1: stacktrace: Make stack walk callback consistent with generic code
  ARM: 9265/1: pass -march= only to compiler
  ...

ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA

2022-11-28T11:57:36+00:00

When building with CONFIG_THUMB2_KERNEL=y + a version of clang from
Debian using CROSS_COMPILE=arm-linux-gnueabihf-, the following warning
occurs frequently:

  :383:9: warning: '__thumb2__' macro redefined [-Wmacro-redefined]
  #define __thumb2__ 2
          ^
  :353:9: note: previous definition is here
  #define __thumb2__ 1
          ^
  1 warning generated.

Debian carries a downstream patch that changes the default CPU of the
arm-linux-gnueabihf target from 'arm1176jzf-s' (v6) to 'cortex-a7' (v7).
As a result, '-mthumb' defines both '__thumb__' and '__thumb2__'. The
define of '__thumb2__' via the command line was purposefully added to
catch a situation like this.

In a similar vein as commit 26b12e084bce ("ARM: 9264/1: only use
-mtp=cp15 for the compiler"), do not add '-mthumb' to AFLAGS_ISA, as it
is already passed to the assembler via '-Wa,-mthumb' and '__thumb2__' is
already defined for preprocessing.

Link: https://salsa.debian.org/pkg-llvm-team/llvm-toolchain/-/raw/622dbcbd40b316ed3905a2d25d9623544a06e6b1/debian/patches/930008-arm.diff

Fixes: 1d2e9b67b001 ("ARM: 9265/1: pass -march= only to compiler")
Reported-by: "kernelci.org bot" 
Reviewed-by: Nick Desaulniers 
Tested-by: Nick Desaulniers 
Reviewed-by: Ard Biesheuvel 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Russell King (Oracle)

ARM: 9265/1: pass -march= only to compiler

2022-11-08T18:36:18+00:00

When both -march= and -Wa,-march= are specified for assembler or
assembler-with-cpp sources, GCC and Clang will prefer the -Wa,-march=
value but Clang will warn that -march= is unused.

warning: argument unused during compilation: '-march=armv6k'
[-Wunused-command-line-argument]

This is the top group of warnings we observe when using clang to
assemble the kernel via `ARCH=arm make LLVM=1`.

Split the arch-y make variable into two, so that -march= flags only get
passed to the compiler, not the assembler. -D flags are added to
KBUILD_CPPFLAGS which is used for both C and assembler-with-cpp sources.

Clang is trying to warn that it doesn't support different values for
-march= and -Wa,-march= (like GCC does, but the kernel doesn't need this)
though the value of the preprocessor define __thumb2__ is based on
-march=. Make sure to re-set __thumb2__ via -D flag for assembler
sources now that we're no longer passing -march= to the assembler. Set
it to a different value than the preprocessor would for -march= in case
-march= gets accidentally re-added to KBUILD_AFLAGS in the future.
Thanks to Ard and Nathan for this suggestion.

Link: https://github.com/ClangBuiltLinux/linux/issues/1315
Link: https://github.com/ClangBuiltLinux/linux/issues/1587
Link: https://github.com/llvm/llvm-project/issues/55656

Suggested-by: Ard Biesheuvel 
Suggested-by: Nathan Chancellor 
Reviewed-by: Nathan Chancellor 
Tested-by: Nathan Chancellor 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Russell King (Oracle)

ARM: 9264/1: only use -mtp=cp15 for the compiler

2022-11-08T18:36:18+00:00

Avoids an error from the assembler for CONFIG_THUMB2 kernels:

clang-15: error: hardware TLS register is not supported for the thumbv4t
sub-architecture

This flag only makes sense to pass to the compiler, not the assembler.

Perhaps CFLAGS_ABI can be renamed to CPPFLAGS_ABI to reflect that they
will be passed to both the compiler and assembler for sources that
require pre-processing.

Reviewed-by: Nathan Chancellor 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Russell King (Oracle)

ARM: 9262/1: remove lazy evaluation in Makefile

2022-11-07T14:19:04+00:00

arch-y and tune-y used lazy evaluation since they used to contain

cc-option checks. They don't any longer, so just eagerly evaluate these
command line flags.

Reviewed-by: Nathan Chancellor 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Russell King (Oracle)

Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2022-10-10T19:00:45+00:00

Pull Kbuild updates from Masahiro Yamada:

- Remove potentially incomplete targets when Kbuid is interrupted by
SIGINT etc in case GNU Make may miss to do that when stderr is piped
to another program.

- Rewrite the single target build so it works more correctly.

- Fix rpm-pkg builds with V=1.

- List top-level subdirectories in ./Kbuild.

- Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in
kallsyms.

- Avoid two different modules in lib/zstd/ having shared code, which
potentially causes building the common code as build-in and modular
back-and-forth.

- Unify two modpost invocations to optimize the build process.

- Remove head-y syntax in favor of linker scripts for placing
particular sections in the head of vmlinux.

- Bump the minimal GNU Make version to 3.82.

- Clean up misc Makefiles and scripts.

* tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
docs: bump minimal GNU Make version to 3.82
ia64: simplify esi object addition in Makefile
Revert "kbuild: Check if linker supports the -X option"
kbuild: rebuild .vmlinux.export.o when its prerequisite is updated
kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o
zstd: Fixing mixed module-builtin objects
kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols
kallsyms: take the input file instead of reading stdin
kallsyms: drop duplicated ignore patterns from kallsyms.c
kbuild: reuse mksysmap output for kallsyms
mksysmap: update comment about __crc_*
kbuild: remove head-y syntax
kbuild: use obj-y instead extra-y for objects placed at the head
kbuild: hide error checker logs for V=1 builds
kbuild: re-run modpost when it is updated
kbuild: unify two modpost invocations
kbuild: move vmlinux.o rule to the top Makefile
kbuild: move .vmlinux.objs rule to Makefile.modpost
kbuild: list sub-directories in ./Kbuild
Makefile.compiler: replace cc-ifversion with compiler-specific macros
...

Merge tag 'arm-soc-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

2022-10-06T18:22:25+00:00

Pull ARM SoC updates from Arnd Bergmann:
 "The main changes this time are for the organization of the Kconfig
  files, introducing per-vendor top-level options on arm64 to match
  those on arm32, and making the platform selection on arm32 more
  uniform, in particular for the remaining StrongARM platforms that
  still have a couple of special cases compared to the more recent ones.

  I also did a cleanup of the old Footbridge platform, which was the
  last holdout for the phys_to_dma()/dma_to_phys() interface that is now
  completely gone from arm32, completing work started by Christoph
  Hellwig"

* tag 'arm-soc-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (21 commits)
  ARM: aspeed: Kconfig: Fix indentation
  ARM: Drop CMDLINE_* dependency on ATAGS
  ARM: Drop CMDLINE_FORCE dependency on !ARCH_MULTIPLATFORM
  ARM: s3c: remove orphan declarations from arch/arm/mach-s3c/devs.h
  pxa: Drop if with an always false condition
  ARM: orion: fix include path
  ARM: shmobile: Drop selecting SOC_BUS
  arm64: renesas: Drop selecting SOC_BUS
  ARM: disallow PCI with MMU=n again
  ARM: footbridge: remove custom DMA address handling
  MAINTAINERS: Add BCM4908 maintainer to BCMBCA entry
  ARM: footbridge: move isa-dma support into footbridge
  ARM: footbridge: remove leftover from personal-server
  ARM: footbridge: remove addin mode
  arm64: Kconfig.platforms: Group NXP platforms together
  arm64: Kconfig.platforms: Re-organized Broadcom menu
  ARM: make ARCH_MULTIPLATFORM user-visible
  ARM: fix XIP_KERNEL dependencies
  ARM: Kconfig: clean up platform selection
  ARM: simplify machdirs/platdirs handling
  ...

kbuild: remove head-y syntax

2022-10-02T09:06:03+00:00

Kbuild puts the objects listed in head-y at the head of vmlinux.
Conventionally, we do this for head*.S, which contains the kernel entry
point.

A counter approach is to control the section order by the linker script.
Actually, the code marked as __HEAD goes into the ".head.text" section,
which is placed before the normal ".text" section.

I do not know if both of them are needed. From the build system
perspective, head-y is not mandatory. If you can achieve the proper code
placement by the linker script only, it would be cleaner.

I collected the current head-y objects into head-object-list.txt. It is
a whitelist. My hope is it will be reduced in the long run.

Signed-off-by: Masahiro Yamada 
Tested-by: Nick Desaulniers 
Reviewed-by: Nicolas Schier

ARM: 9226/1: disable FDPIC ABI

2022-08-31T13:50:07+00:00

When building with an arm-*-uclinuxfdpiceabi toolchain, the FDPIC ABI is
enabled by default but should not be used to build the kernel.
Therefore, pass -mno-fdpic if supported by the compiler.

Signed-off-by: Ben Wolsieffer 
Signed-off-by: Russell King (Oracle)