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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>
29 lines
560 B
C
29 lines
560 B
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2023 SiFive
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*/
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#include <linux/export.h>
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#include <linux/preempt.h>
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#include <asm/csr.h>
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#include <asm/fpu.h>
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#include <asm/processor.h>
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#include <asm/switch_to.h>
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void kernel_fpu_begin(void)
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{
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preempt_disable();
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fstate_save(current, task_pt_regs(current));
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csr_set(CSR_SSTATUS, SR_FS);
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}
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EXPORT_SYMBOL_GPL(kernel_fpu_begin);
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void kernel_fpu_end(void)
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{
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csr_clear(CSR_SSTATUS, SR_FS);
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fstate_restore(current, task_pt_regs(current));
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preempt_enable();
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}
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EXPORT_SYMBOL_GPL(kernel_fpu_end);
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