diff options
Diffstat (limited to 'arch/s390/include/asm/fpu')
| -rw-r--r-- | arch/s390/include/asm/fpu/api.h | 116 | ||||
| -rw-r--r-- | arch/s390/include/asm/fpu/internal.h | 62 | ||||
| -rw-r--r-- | arch/s390/include/asm/fpu/types.h | 38 |
3 files changed, 216 insertions, 0 deletions
diff --git a/arch/s390/include/asm/fpu/api.h b/arch/s390/include/asm/fpu/api.h new file mode 100644 index 000000000..34a7ae684 --- /dev/null +++ b/arch/s390/include/asm/fpu/api.h @@ -0,0 +1,116 @@ +/* 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 <brueckner@linux.vnet.ibm.com> + */ + +#ifndef _ASM_S390_FPU_API_H +#define _ASM_S390_FPU_API_H + +#include <linux/preempt.h> + +void save_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_V0V7) + +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 */ diff --git a/arch/s390/include/asm/fpu/internal.h b/arch/s390/include/asm/fpu/internal.h new file mode 100644 index 000000000..4a71dbbf7 --- /dev/null +++ b/arch/s390/include/asm/fpu/internal.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * FPU state and register content conversion primitives + * + * Copyright IBM Corp. 2015 + * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> + */ + +#ifndef _ASM_S390_FPU_INTERNAL_H +#define _ASM_S390_FPU_INTERNAL_H + +#include <linux/string.h> +#include <asm/ctl_reg.h> +#include <asm/fpu/types.h> + +static inline void save_vx_regs(__vector128 *vxrs) +{ + asm volatile( + " la 1,%0\n" + " .word 0xe70f,0x1000,0x003e\n" /* vstm 0,15,0(1) */ + " .word 0xe70f,0x1100,0x0c3e\n" /* vstm 16,31,256(1) */ + : "=Q" (*(struct vx_array *) vxrs) : : "1"); +} + +static inline void convert_vx_to_fp(freg_t *fprs, __vector128 *vxrs) +{ + int i; + + for (i = 0; i < __NUM_FPRS; i++) + fprs[i] = *(freg_t *)(vxrs + i); +} + +static inline void convert_fp_to_vx(__vector128 *vxrs, freg_t *fprs) +{ + int i; + + for (i = 0; i < __NUM_FPRS; i++) + *(freg_t *)(vxrs + i) = fprs[i]; +} + +static inline void fpregs_store(_s390_fp_regs *fpregs, struct fpu *fpu) +{ + fpregs->pad = 0; + fpregs->fpc = fpu->fpc; + if (MACHINE_HAS_VX) + convert_vx_to_fp((freg_t *)&fpregs->fprs, fpu->vxrs); + else + memcpy((freg_t *)&fpregs->fprs, fpu->fprs, + sizeof(fpregs->fprs)); +} + +static inline void fpregs_load(_s390_fp_regs *fpregs, struct fpu *fpu) +{ + fpu->fpc = fpregs->fpc; + if (MACHINE_HAS_VX) + convert_fp_to_vx(fpu->vxrs, (freg_t *)&fpregs->fprs); + else + memcpy(fpu->fprs, (freg_t *)&fpregs->fprs, + sizeof(fpregs->fprs)); +} + +#endif /* _ASM_S390_FPU_INTERNAL_H */ diff --git a/arch/s390/include/asm/fpu/types.h b/arch/s390/include/asm/fpu/types.h new file mode 100644 index 000000000..d889e9436 --- /dev/null +++ b/arch/s390/include/asm/fpu/types.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * FPU data structures + * + * Copyright IBM Corp. 2015 + * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com> + */ + +#ifndef _ASM_S390_FPU_TYPES_H +#define _ASM_S390_FPU_TYPES_H + +#include <asm/sigcontext.h> + +struct fpu { + __u32 fpc; /* Floating-point control */ + void *regs; /* Pointer to the current save area */ + union { + /* Floating-point register save area */ + freg_t fprs[__NUM_FPRS]; + /* Vector register save area */ + __vector128 vxrs[__NUM_VXRS]; + }; +}; + +/* 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 */ |