asm/fpu/api.h

1 /* SPDX-License-Identifier: GPL-2.0 */
3  * In-kernel FPU support functions
6  * Consider these guidelines before using in-kernel FPU functions:
8  *  1. Use kernel_fpu_begin() and kernel_fpu_end() to enclose all in-kernel
9  *     use of floating-point or vector registers and instructions.
14  *     a) If your function typically runs in process-context, use the lower
16  *     b) If your function typically runs in soft-irq or hard-irq context,
32  *  5. To use vector floating-point instructions, specify the KERNEL_FPC
33  *     flag to save and restore floating-point controls in addition to any
36  *  6. To use floating-point registers and instructions only, specify the
38  *     registers V0 to V15 and floating-point controls.
48 #include <asm/asm-extable.h>
56  * sfpc_safe - Set floating point control register safely.
57  * @fpc: new value for floating point control register
59  * Set floating point control register. This may lead to an exception,
62  * set the floating point control register to zero.
107 	state->mask = S390_lowcore.fpu_flags;  in kernel_fpu_begin()
111 	else if (state->mask & flags)  in kernel_fpu_begin()
112 		/* Save FPU/vector register in-use by the kernel */  in kernel_fpu_begin()
119 	S390_lowcore.fpu_flags = state->mask;  in kernel_fpu_end()
120 	if (state->mask & flags)  in kernel_fpu_end()
121 		/* Restore FPU/vector register in-use by the kernel */  in kernel_fpu_end()