Commit 4cfb3613 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Catalin Marinas
Browse files

arm64: add support for kernel mode NEON 



Add <asm/neon.h> containing kernel_neon_begin/kernel_neon_end function
declarations and corresponding definitions in fpsimd.c

These are needed to wrap uses of NEON in kernel mode. The names are
identical to the ones used in arm/ so code using intrinsics or
vectorized by GCC can be shared between arm and arm64.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 178cd9ce

arch/arm64/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -96,6 +96,9 @@ config SWIOTLB 
config IOMMU_HELPER

	def_bool SWIOTLB



config KERNEL_MODE_NEON

	def_bool y



source "init/Kconfig"



source "kernel/Kconfig.freezer"

arch/arm64/include/asm/neon.h

0 → 100644
+14 −0
Original line number Diff line number Diff line 
/*

 * linux/arch/arm64/include/asm/neon.h

 *

 * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#define cpu_has_neon()		(1)



void kernel_neon_begin(void);

void kernel_neon_end(void);

arch/arm64/kernel/fpsimd.c

+28 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/init.h>

#include <linux/sched.h>

#include <linux/signal.h>

#include <linux/hardirq.h>



#include <asm/fpsimd.h>

#include <asm/cputype.h>
@@ -83,6 +84,33 @@ void fpsimd_flush_thread(void) 
	fpsimd_load_state(&current->thread.fpsimd_state);

}



#ifdef CONFIG_KERNEL_MODE_NEON



/*

 * Kernel-side NEON support functions

 */

void kernel_neon_begin(void)

{

	/* Avoid using the NEON in interrupt context */

	BUG_ON(in_interrupt());

	preempt_disable();



	if (current->mm)

		fpsimd_save_state(&current->thread.fpsimd_state);

}

EXPORT_SYMBOL(kernel_neon_begin);



void kernel_neon_end(void)

{

	if (current->mm)

		fpsimd_load_state(&current->thread.fpsimd_state);



	preempt_enable();

}

EXPORT_SYMBOL(kernel_neon_end);



#endif /* CONFIG_KERNEL_MODE_NEON */



/*

 * FP/SIMD support code initialisation.

 */

CRA Git | Maintained and supported by SUSTech CRA and CCSE