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arm64: add support for kernel mode NEON

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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: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Ard Biesheuvel 2013-07-09 14:18:12 +01:00 committed by Catalin Marinas
parent 178cd9ce37
commit 4cfb361364
3 changed files with 45 additions and 0 deletions
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3
arch/arm64/Kconfig
View File

@ -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"

14
arch/arm64/include/asm/neon.h Normal file
View File

@ -0,0 +1,14 @@
/*
* 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);

28
arch/arm64/kernel/fpsimd.c
View File

@ -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.
*/