From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/s390/include/asm/fpu/api.h | 119 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) create mode 100644 arch/s390/include/asm/fpu/api.h (limited to 'arch/s390/include/asm/fpu/api.h') diff --git a/arch/s390/include/asm/fpu/api.h b/arch/s390/include/asm/fpu/api.h new file mode 100644 index 0000000000..9acf48e53a --- /dev/null +++ b/arch/s390/include/asm/fpu/api.h @@ -0,0 +1,119 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * In-kernel FPU support functions + * + * + * Consider these guidelines before using in-kernel FPU functions: + * + * 1. Use kernel_fpu_begin() and kernel_fpu_end() to enclose all in-kernel + * use of floating-point or vector registers and instructions. + * + * 2. For kernel_fpu_begin(), specify the vector register range you want to + * use with the KERNEL_VXR_* constants. Consider these usage guidelines: + * + * a) If your function typically runs in process-context, use the lower + * half of the vector registers, for example, specify KERNEL_VXR_LOW. + * b) If your function typically runs in soft-irq or hard-irq context, + * prefer using the upper half of the vector registers, for example, + * specify KERNEL_VXR_HIGH. + * + * If you adhere to these guidelines, an interrupted process context + * does not require to save and restore vector registers because of + * disjoint register ranges. + * + * Also note that the __kernel_fpu_begin()/__kernel_fpu_end() functions + * includes logic to save and restore up to 16 vector registers at once. + * + * 3. You can nest kernel_fpu_begin()/kernel_fpu_end() by using different + * struct kernel_fpu states. Vector registers that are in use by outer + * levels are saved and restored. You can minimize the save and restore + * effort by choosing disjoint vector register ranges. + * + * 5. To use vector floating-point instructions, specify the KERNEL_FPC + * flag to save and restore floating-point controls in addition to any + * vector register range. + * + * 6. To use floating-point registers and instructions only, specify the + * KERNEL_FPR flag. This flag triggers a save and restore of vector + * registers V0 to V15 and floating-point controls. + * + * Copyright IBM Corp. 2015 + * Author(s): Hendrik Brueckner + */ + +#ifndef _ASM_S390_FPU_API_H +#define _ASM_S390_FPU_API_H + +#include +#include + +void save_fpu_regs(void); +void load_fpu_regs(void); +void __load_fpu_regs(void); + +static inline int test_fp_ctl(u32 fpc) +{ + u32 orig_fpc; + int rc; + + asm volatile( + " efpc %1\n" + " sfpc %2\n" + "0: sfpc %1\n" + " la %0,0\n" + "1:\n" + EX_TABLE(0b,1b) + : "=d" (rc), "=&d" (orig_fpc) + : "d" (fpc), "0" (-EINVAL)); + return rc; +} + +#define KERNEL_FPC 1 +#define KERNEL_VXR_V0V7 2 +#define KERNEL_VXR_V8V15 4 +#define KERNEL_VXR_V16V23 8 +#define KERNEL_VXR_V24V31 16 + +#define KERNEL_VXR_LOW (KERNEL_VXR_V0V7|KERNEL_VXR_V8V15) +#define KERNEL_VXR_MID (KERNEL_VXR_V8V15|KERNEL_VXR_V16V23) +#define KERNEL_VXR_HIGH (KERNEL_VXR_V16V23|KERNEL_VXR_V24V31) + +#define KERNEL_VXR (KERNEL_VXR_LOW|KERNEL_VXR_HIGH) +#define KERNEL_FPR (KERNEL_FPC|KERNEL_VXR_LOW) + +struct kernel_fpu; + +/* + * Note the functions below must be called with preemption disabled. + * Do not enable preemption before calling __kernel_fpu_end() to prevent + * an corruption of an existing kernel FPU state. + * + * Prefer using the kernel_fpu_begin()/kernel_fpu_end() pair of functions. + */ +void __kernel_fpu_begin(struct kernel_fpu *state, u32 flags); +void __kernel_fpu_end(struct kernel_fpu *state, u32 flags); + + +static inline void kernel_fpu_begin(struct kernel_fpu *state, u32 flags) +{ + preempt_disable(); + state->mask = S390_lowcore.fpu_flags; + if (!test_cpu_flag(CIF_FPU)) + /* Save user space FPU state and register contents */ + save_fpu_regs(); + else if (state->mask & flags) + /* Save FPU/vector register in-use by the kernel */ + __kernel_fpu_begin(state, flags); + S390_lowcore.fpu_flags |= flags; +} + +static inline void kernel_fpu_end(struct kernel_fpu *state, u32 flags) +{ + S390_lowcore.fpu_flags = state->mask; + if (state->mask & flags) + /* Restore FPU/vector register in-use by the kernel */ + __kernel_fpu_end(state, flags); + preempt_enable(); +} + +#endif /* _ASM_S390_FPU_API_H */ -- cgit v1.2.3