From: Samuel Holland <samuel.holland@sifive.com>
To: Andrew Morton <akpm@linux-foundation.org>,
linux-arm-kernel@lists.infradead.org, x86@kernel.org
Cc: linux-arch@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org,
Samuel Holland <samuel.holland@sifive.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
loongarch@lists.linux.dev, linux-riscv@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, Christoph Hellwig <hch@lst.de>
Subject: [PATCH v4 10/15] x86: Implement ARCH_HAS_KERNEL_FPU_SUPPORT
Date: Fri, 29 Mar 2024 00:18:25 -0700 [thread overview]
Message-ID: <20240329072441.591471-11-samuel.holland@sifive.com> (raw)
In-Reply-To: <20240329072441.591471-1-samuel.holland@sifive.com>
x86 already provides kernel_fpu_begin() and kernel_fpu_end(), but in a
different header. Add a wrapper header, and export the CFLAGS
adjustments as found in lib/Makefile.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
---
(no changes since v1)
arch/x86/Kconfig | 1 +
arch/x86/Makefile | 20 ++++++++++++++++++++
arch/x86/include/asm/fpu.h | 13 +++++++++++++
3 files changed, 34 insertions(+)
create mode 100644 arch/x86/include/asm/fpu.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 39886bab943a..7c9d032ee675 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -83,6 +83,7 @@ config X86
select ARCH_HAS_FORTIFY_SOURCE
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_HAS_KCOV if X86_64
+ select ARCH_HAS_KERNEL_FPU_SUPPORT
select ARCH_HAS_MEM_ENCRYPT
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 662d9d4033e6..5a5f5999c505 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -74,6 +74,26 @@ KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
KBUILD_RUSTFLAGS += --target=$(objtree)/scripts/target.json
KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
+#
+# CFLAGS for compiling floating point code inside the kernel.
+#
+CC_FLAGS_FPU := -msse -msse2
+ifdef CONFIG_CC_IS_GCC
+# Stack alignment mismatch, proceed with caution.
+# GCC < 7.1 cannot compile code using `double` and -mpreferred-stack-boundary=3
+# (8B stack alignment).
+# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
+#
+# The "-msse" in the first argument is there so that the
+# -mpreferred-stack-boundary=3 build error:
+#
+# -mpreferred-stack-boundary=3 is not between 4 and 12
+#
+# can be triggered. Otherwise gcc doesn't complain.
+CC_FLAGS_FPU += -mhard-float
+CC_FLAGS_FPU += $(call cc-option,-msse -mpreferred-stack-boundary=3,-mpreferred-stack-boundary=4)
+endif
+
ifeq ($(CONFIG_X86_KERNEL_IBT),y)
#
# Kernel IBT has S_CET.NOTRACK_EN=0, as such the compilers must not generate
diff --git a/arch/x86/include/asm/fpu.h b/arch/x86/include/asm/fpu.h
new file mode 100644
index 000000000000..b2743fe19339
--- /dev/null
+++ b/arch/x86/include/asm/fpu.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef _ASM_X86_FPU_H
+#define _ASM_X86_FPU_H
+
+#include <asm/fpu/api.h>
+
+#define kernel_fpu_available() true
+
+#endif /* ! _ASM_X86_FPU_H */
--
2.44.0
next prev parent reply other threads:[~2024-03-29 7:32 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-29 7:18 [PATCH v4 00/15] Unified cross-architecture kernel-mode FPU API Samuel Holland
2024-03-29 7:18 ` [PATCH v4 01/15] arch: Add ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29 7:18 ` [PATCH v4 02/15] ARM: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29 7:18 ` [PATCH v4 03/15] ARM: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
2024-03-29 7:18 ` [PATCH v4 04/15] arm64: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29 7:18 ` [PATCH v4 05/15] arm64: crypto: Use CC_FLAGS_FPU for NEON CFLAGS Samuel Holland
2024-03-29 7:18 ` [PATCH v4 06/15] lib/raid6: " Samuel Holland
2024-03-29 7:18 ` [PATCH v4 07/15] LoongArch: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-03-29 7:18 ` [PATCH v4 08/15] powerpc: " Samuel Holland
2024-03-29 7:18 ` [PATCH v4 09/15] x86/fpu: Fix asm/fpu/types.h include guard Samuel Holland
2024-03-29 17:30 ` Dave Hansen
2024-03-29 7:18 ` Samuel Holland [this message]
2024-03-29 17:28 ` [PATCH v4 10/15] x86: Implement ARCH_HAS_KERNEL_FPU_SUPPORT Dave Hansen
2024-03-29 18:02 ` Samuel Holland
2024-03-29 7:18 ` [PATCH v4 11/15] riscv: Add support for kernel-mode FPU Samuel Holland
2024-03-29 7:18 ` [PATCH v4 12/15] drm/amd/display: Only use hard-float, not altivec on powerpc Samuel Holland
2024-04-30 17:28 ` Harry Wentland
2024-03-29 7:18 ` [PATCH v4 13/15] drm/amd/display: Use ARCH_HAS_KERNEL_FPU_SUPPORT Samuel Holland
2024-04-10 22:21 ` Thiago Jung Bauermann
2024-04-10 22:47 ` Samuel Holland
2024-04-11 1:02 ` Thiago Jung Bauermann
2024-04-11 1:11 ` Samuel Holland
2024-04-11 1:27 ` Thiago Jung Bauermann
2024-04-11 7:15 ` Ard Biesheuvel
2024-04-11 7:31 ` Arnd Bergmann
2024-04-12 1:54 ` Dave Airlie
2024-04-30 17:29 ` Harry Wentland
2024-03-29 7:18 ` [PATCH v4 14/15] selftests/fpu: Move FP code to a separate translation unit Samuel Holland
2024-03-29 7:18 ` [PATCH v4 15/15] selftests/fpu: Allow building on other architectures Samuel Holland
2024-04-03 12:51 ` [PATCH v4 00/15] Unified cross-architecture kernel-mode FPU API Christian König
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