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Message-ID: <20240327200157.1097089-1-samuel.holland@sifive.com>
Date: Wed, 27 Mar 2024 13:00:31 -0700
From: Samuel Holland <samuel.holland@...ive.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
linux-arm-kernel@...ts.infradead.org,
x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
linux-arch@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org,
linux-riscv@...ts.infradead.org,
Christoph Hellwig <hch@....de>,
loongarch@...ts.linux.dev,
amd-gfx@...ts.freedesktop.org,
Samuel Holland <samuel.holland@...ive.com>,
Borislav Petkov <bp@...en8.de>,
Catalin Marinas <catalin.marinas@....com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Huacai Chen <chenhuacai@...nel.org>,
Ingo Molnar <mingo@...hat.com>,
Jonathan Corbet <corbet@....net>,
Masahiro Yamada <masahiroy@...nel.org>,
Nathan Chancellor <nathan@...nel.org>,
Nicolas Schier <nicolas@...sle.eu>,
Russell King <linux@...linux.org.uk>,
Thomas Gleixner <tglx@...utronix.de>,
Will Deacon <will@...nel.org>,
linux-doc@...r.kernel.org,
linux-kbuild@...r.kernel.org
Subject: [PATCH v3 00/14] Unified cross-architecture kernel-mode FPU API
This series unifies the kernel-mode FPU API across several architectures
by wrapping the existing functions (where needed) in consistently-named
functions placed in a consistent header location, with mostly the same
semantics: they can be called from preemptible or non-preemptible task
context, and are not assumed to be reentrant. Architectures are also
expected to provide CFLAGS adjustments for compiling FPU-dependent code.
For the moment, SIMD/vector units are out of scope for this common API.
This allows us to remove the ifdeffery and duplicated Makefile logic at
each FPU user. It then implements the common API on RISC-V, and converts
a couple of users to the new API: the AMDGPU DRM driver, and the FPU
self test.
The underlying goal of this series is to allow using newer AMD GPUs
(e.g. Navi) on RISC-V boards such as SiFive's HiFive Unmatched. Those
GPUs need CONFIG_DRM_AMD_DC_FP to initialize, which requires kernel-mode
FPU support.
Previous versions:
v2: https://lore.kernel.org/linux-kernel/20231228014220.3562640-1-samuel.holland@sifive.com/
v1: https://lore.kernel.org/linux-kernel/20231208055501.2916202-1-samuel.holland@sifive.com/
v0: https://lore.kernel.org/linux-kernel/20231122030621.3759313-1-samuel.holland@sifive.com/
Changes in v3:
- Rebase on v6.9-rc1
- Limit ARCH_HAS_KERNEL_FPU_SUPPORT to 64BIT
Changes in v2:
- Add documentation explaining the built-time and runtime APIs
- Add a linux/fpu.h header for generic isolation enforcement
- Remove file name from header comment
- Clean up arch/arm64/lib/Makefile, like for arch/arm
- Remove RISC-V architecture-specific preprocessor check
- Split altivec removal to a separate patch
- Use linux/fpu.h instead of asm/fpu.h in consumers
- Declare test_fpu() in a header
Michael Ellerman (1):
drm/amd/display: Only use hard-float, not altivec on powerpc
Samuel Holland (13):
arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT
ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS
arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
arm64: crypto: Use CC_FLAGS_FPU for NEON CFLAGS
lib/raid6: Use CC_FLAGS_FPU for NEON CFLAGS
LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
powerpc: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
x86: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
riscv: Add support for kernel-mode FPU
drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT
selftests/fpu: Move FP code to a separate translation unit
selftests/fpu: Allow building on other architectures
Documentation/core-api/floating-point.rst | 78 +++++++++++++++++++
Documentation/core-api/index.rst | 1 +
Makefile | 5 ++
arch/Kconfig | 6 ++
arch/arm/Kconfig | 1 +
arch/arm/Makefile | 7 ++
arch/arm/include/asm/fpu.h | 15 ++++
arch/arm/lib/Makefile | 3 +-
arch/arm64/Kconfig | 1 +
arch/arm64/Makefile | 9 ++-
arch/arm64/include/asm/fpu.h | 15 ++++
arch/arm64/lib/Makefile | 6 +-
arch/loongarch/Kconfig | 1 +
arch/loongarch/Makefile | 5 +-
arch/loongarch/include/asm/fpu.h | 1 +
arch/powerpc/Kconfig | 1 +
arch/powerpc/Makefile | 5 +-
arch/powerpc/include/asm/fpu.h | 28 +++++++
arch/riscv/Kconfig | 1 +
arch/riscv/Makefile | 3 +
arch/riscv/include/asm/fpu.h | 16 ++++
arch/riscv/kernel/Makefile | 1 +
arch/riscv/kernel/kernel_mode_fpu.c | 28 +++++++
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 20 +++++
arch/x86/include/asm/fpu.h | 13 ++++
drivers/gpu/drm/amd/display/Kconfig | 2 +-
.../gpu/drm/amd/display/amdgpu_dm/dc_fpu.c | 35 +--------
drivers/gpu/drm/amd/display/dc/dml/Makefile | 36 +--------
drivers/gpu/drm/amd/display/dc/dml2/Makefile | 36 +--------
include/linux/fpu.h | 12 +++
lib/Kconfig.debug | 2 +-
lib/Makefile | 26 +------
lib/raid6/Makefile | 31 ++------
lib/test_fpu.h | 8 ++
lib/{test_fpu.c => test_fpu_glue.c} | 37 ++-------
lib/test_fpu_impl.c | 37 +++++++++
37 files changed, 343 insertions(+), 190 deletions(-)
create mode 100644 Documentation/core-api/floating-point.rst
create mode 100644 arch/arm/include/asm/fpu.h
create mode 100644 arch/arm64/include/asm/fpu.h
create mode 100644 arch/powerpc/include/asm/fpu.h
create mode 100644 arch/riscv/include/asm/fpu.h
create mode 100644 arch/riscv/kernel/kernel_mode_fpu.c
create mode 100644 arch/x86/include/asm/fpu.h
create mode 100644 include/linux/fpu.h
create mode 100644 lib/test_fpu.h
rename lib/{test_fpu.c => test_fpu_glue.c} (71%)
create mode 100644 lib/test_fpu_impl.c
--
2.43.1
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