linux/arch/arm/include/asm/simd.h

/* SPDX-License-Identifier: GPL-2.0 */

#include <linux/hardirq.h>

static __must_check inline bool may_use_simd(void)
{
	return IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !in_hardirq();
}
ARM: 9283/1: permit non-nested kernel mode NEON in softirq context We currently only permit kernel mode NEON in process context, to avoid the need to preserve/restore the NEON register file when taking an exception while running in the kernel. Like we did on arm64, we can relax this restriction substantially, by permitting kernel mode NEON from softirq context, while ensuring that softirq processing is disabled when the NEON is being used in task context. This guarantees that only NEON context belonging to user space needs to be preserved and restored, which is already taken care of. This is especially relevant for network encryption, where incoming frames are typically handled in softirq context, and deferring software decryption to a kernel thread or falling back to C code are both undesirable from a performance PoV. Tested-by: Martin Willi <martin@strongswan.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> 2022-12-22 18:52:23 +01:00			`/* SPDX-License-Identifier: GPL-2.0 */`

			`#include <linux/hardirq.h>`

			`static __must_check inline bool may_use_simd(void)`
			`{`
			`return IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && !in_hardirq();`
			`}`