From d0b2f91bede3bd5e3d24dd6803e56eee959c1797 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Thu, 20 Oct 2016 00:10:27 -0300 Subject: Linux-libre 4.8.2-gnu --- arch/s390/include/asm/fpu/api.h | 75 +++++++++++++++++++++++++++++++++++++++ arch/s390/include/asm/fpu/types.h | 10 ++++++ 2 files changed, 85 insertions(+) (limited to 'arch/s390/include/asm/fpu') diff --git a/arch/s390/include/asm/fpu/api.h b/arch/s390/include/asm/fpu/api.h index 8ae236b0f..6aba6fc40 100644 --- a/arch/s390/include/asm/fpu/api.h +++ b/arch/s390/include/asm/fpu/api.h @@ -1,6 +1,41 @@ /* * 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 */ @@ -8,6 +43,8 @@ #ifndef _ASM_S390_FPU_API_H #define _ASM_S390_FPU_API_H +#include + void save_fpu_regs(void); static inline int test_fp_ctl(u32 fpc) @@ -27,4 +64,42 @@ static inline int test_fp_ctl(u32 fpc) return rc; } +#define KERNEL_VXR_V0V7 1 +#define KERNEL_VXR_V8V15 2 +#define KERNEL_VXR_V16V23 4 +#define KERNEL_VXR_V24V31 8 +#define KERNEL_FPR 16 +#define KERNEL_FPC 256 + +#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_FPU_MASK (KERNEL_VXR_LOW|KERNEL_VXR_HIGH|KERNEL_FPR) + +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); + + +static inline void kernel_fpu_begin(struct kernel_fpu *state, u32 flags) +{ + preempt_disable(); + __kernel_fpu_begin(state, flags); +} + +static inline void kernel_fpu_end(struct kernel_fpu *state) +{ + __kernel_fpu_end(state); + preempt_enable(); +} + #endif /* _ASM_S390_FPU_API_H */ diff --git a/arch/s390/include/asm/fpu/types.h b/arch/s390/include/asm/fpu/types.h index fe937c9b6..bce255ead 100644 --- a/arch/s390/include/asm/fpu/types.h +++ b/arch/s390/include/asm/fpu/types.h @@ -24,4 +24,14 @@ struct fpu { /* VX array structure for address operand constraints in inline assemblies */ struct vx_array { __vector128 _[__NUM_VXRS]; }; +/* In-kernel FPU state structure */ +struct kernel_fpu { + u32 mask; + u32 fpc; + union { + freg_t fprs[__NUM_FPRS]; + __vector128 vxrs[__NUM_VXRS]; + }; +}; + #endif /* _ASM_S390_FPU_TYPES_H */ -- cgit v1.2.3-54-g00ecf