From: Samuel Holland <samuel.holland@sifive.com>
To: linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
linux-riscv@lists.infradead.org,
Christoph Hellwig <hch@infradead.org>
Cc: linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
linux-arch@vger.kernel.org,
Samuel Holland <samuel.holland@sifive.com>
Subject: [RFC PATCH 04/12] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
Date: Thu, 7 Dec 2023 21:54:34 -0800 [thread overview]
Message-ID: <20231208055501.2916202-5-samuel.holland@sifive.com> (raw)
In-Reply-To: <20231208055501.2916202-1-samuel.holland@sifive.com>
arm64 provides an equivalent to the common kernel-mode FPU API, but in a
different header and using different function names. Add a wrapper
header, and export CFLAGS adjustments as found in lib/raid6/Makefile.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/Makefile | 9 ++++++++-
arch/arm64/include/asm/fpu.h | 17 +++++++++++++++++
3 files changed, 26 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/include/asm/fpu.h
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7b071a00425d..485ac389ac11 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -30,6 +30,7 @@ config ARM64
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_KCOV
+ select ARCH_HAS_KERNEL_FPU_SUPPORT if KERNEL_MODE_NEON
select ARCH_HAS_KEEPINITRD
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 9a2d3723cd0f..4a65f24c7998 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -36,7 +36,14 @@ ifeq ($(CONFIG_BROKEN_GAS_INST),y)
$(warning Detected assembler with broken .inst; disassembly will be unreliable)
endif
-KBUILD_CFLAGS += -mgeneral-regs-only \
+# The GCC option -ffreestanding is required in order to compile code containing
+# ARM/NEON intrinsics in a non C99-compliant environment (such as the kernel)
+CC_FLAGS_FPU := -ffreestanding
+# Enable <arm_neon.h>
+CC_FLAGS_FPU += -isystem $(shell $(CC) -print-file-name=include)
+CC_FLAGS_NO_FPU := -mgeneral-regs-only
+
+KBUILD_CFLAGS += $(CC_FLAGS_NO_FPU) \
$(compat_vdso) $(cc_has_k_constraint)
KBUILD_CFLAGS += $(call cc-disable-warning, psabi)
KBUILD_AFLAGS += $(compat_vdso)
diff --git a/arch/arm64/include/asm/fpu.h b/arch/arm64/include/asm/fpu.h
new file mode 100644
index 000000000000..664c0a192ab1
--- /dev/null
+++ b/arch/arm64/include/asm/fpu.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/arch/arm64/include/asm/fpu.h
+ *
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef __ASM_FPU_H
+#define __ASM_FPU_H
+
+#include <asm/neon.h>
+
+#define kernel_fpu_available() cpu_has_neon()
+#define kernel_fpu_begin() kernel_neon_begin()
+#define kernel_fpu_end() kernel_neon_end()
+
+#endif /* ! __ASM_FPU_H */
--
2.42.0
next prev parent reply other threads:[~2023-12-08 5:55 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-08 5:54 [RFC PATCH 00/12] Unified cross-architecture kernel-mode FPU API Samuel Holland
2023-12-08 5:54 ` [RFC PATCH 01/12] arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2023-12-11 16:02 ` Christoph Hellwig
2023-12-08 5:54 ` [RFC PATCH 02/12] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2023-12-11 16:04 ` Christoph Hellwig
2023-12-08 5:54 ` [RFC PATCH 03/12] ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
2023-12-11 16:04 ` Christoph Hellwig
2023-12-08 5:54 ` Samuel Holland [this message]
2023-12-11 16:05 ` [RFC PATCH 04/12] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Christoph Hellwig
2023-12-13 16:19 ` Will Deacon
2023-12-08 5:54 ` [RFC PATCH 05/12] lib/raid6: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
2023-12-11 16:07 ` Christoph Hellwig
2023-12-11 16:12 ` Samuel Holland
2023-12-12 7:11 ` Christoph Hellwig
2023-12-08 5:54 ` [RFC PATCH 06/12] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2023-12-11 16:07 ` Christoph Hellwig
2023-12-13 16:13 ` WANG Xuerui
2023-12-08 5:54 ` [RFC PATCH 07/12] powerpc: " Samuel Holland
2023-12-11 16:08 ` Christoph Hellwig
2023-12-08 5:54 ` [RFC PATCH 08/12] x86: " Samuel Holland
2023-12-11 16:08 ` Christoph Hellwig
2023-12-08 5:54 ` [RFC PATCH 09/12] riscv: Add support for kernel-mode FPU Samuel Holland
2023-12-11 16:11 ` Christoph Hellwig
2023-12-11 16:16 ` Samuel Holland
2023-12-08 5:54 ` [RFC PATCH 10/12] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2023-12-11 12:23 ` Michael Ellerman
2023-12-14 1:03 ` Samuel Holland
2023-12-14 3:13 ` Timothy Pearson
2023-12-14 4:45 ` Michael Ellerman
2023-12-08 5:54 ` [RFC PATCH 11/12] selftests/fpu: Move FP code to a separate translation unit Samuel Holland
2023-12-11 16:18 ` Christoph Hellwig
2023-12-08 5:54 ` [RFC PATCH 12/12] selftests/fpu: Allow building on other architectures Samuel Holland
2023-12-11 16:19 ` Christoph Hellwig
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