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authorSamuel Holland <samuel.holland@sifive.com>2024-03-29 10:18:26 +0300
committerAndrew Morton <akpm@linux-foundation.org>2024-05-20 00:36:19 +0300
commit77acc6b55ae46f52bfa4eca52c9fe627f5c3ba3f (patch)
treed801cdaaaf2962be7676ac27f27c80f836c355de /arch/riscv/include
parentb0b8a15bb89e09e12aa6be8ae28128bb656338f1 (diff)
downloadlinux-77acc6b55ae46f52bfa4eca52c9fe627f5c3ba3f.tar.xz
riscv: add support for kernel-mode FPU
This is motivated by the amdgpu DRM driver, which needs floating-point code to support recent hardware. That code is not performance-critical, so only provide a minimal non-preemptible implementation for now. Support is limited to riscv64 because riscv32 requires runtime (libgcc) assistance to convert between doubles and 64-bit integers. Link: https://lkml.kernel.org/r/20240329072441.591471-12-samuel.holland@sifive.com Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Christian König <christian.koenig@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: WANG Xuerui <git@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/riscv/include')
-rw-r--r--arch/riscv/include/asm/fpu.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/fpu.h b/arch/riscv/include/asm/fpu.h
new file mode 100644
index 000000000000..91c04c244e12
--- /dev/null
+++ b/arch/riscv/include/asm/fpu.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 SiFive
+ */
+
+#ifndef _ASM_RISCV_FPU_H
+#define _ASM_RISCV_FPU_H
+
+#include <asm/switch_to.h>
+
+#define kernel_fpu_available() has_fpu()
+
+void kernel_fpu_begin(void);
+void kernel_fpu_end(void);
+
+#endif /* ! _ASM_RISCV_FPU_H */