1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * In-kernel vector facility support functions
4  *
5  * Copyright IBM Corp. 2015
6  * Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
7  */
8 #include <linux/kernel.h>
9 #include <linux/cpu.h>
10 #include <linux/sched.h>
11 #include <asm/fpu/types.h>
12 #include <asm/fpu/api.h>
13 
14 asm(".include \"asm/vx-insn.h\"\n");
15 
__kernel_fpu_begin(struct kernel_fpu * state,u32 flags)16 void __kernel_fpu_begin(struct kernel_fpu *state, u32 flags)
17 {
18 	/*
19 	 * Limit the save to the FPU/vector registers already
20 	 * in use by the previous context
21 	 */
22 	flags &= state->mask;
23 
24 	if (flags & KERNEL_FPC)
25 		/* Save floating point control */
26 		asm volatile("stfpc %0" : "=Q" (state->fpc));
27 
28 	if (!MACHINE_HAS_VX) {
29 		if (flags & KERNEL_VXR_V0V7) {
30 			/* Save floating-point registers */
31 			asm volatile("std 0,%0" : "=Q" (state->fprs[0]));
32 			asm volatile("std 1,%0" : "=Q" (state->fprs[1]));
33 			asm volatile("std 2,%0" : "=Q" (state->fprs[2]));
34 			asm volatile("std 3,%0" : "=Q" (state->fprs[3]));
35 			asm volatile("std 4,%0" : "=Q" (state->fprs[4]));
36 			asm volatile("std 5,%0" : "=Q" (state->fprs[5]));
37 			asm volatile("std 6,%0" : "=Q" (state->fprs[6]));
38 			asm volatile("std 7,%0" : "=Q" (state->fprs[7]));
39 			asm volatile("std 8,%0" : "=Q" (state->fprs[8]));
40 			asm volatile("std 9,%0" : "=Q" (state->fprs[9]));
41 			asm volatile("std 10,%0" : "=Q" (state->fprs[10]));
42 			asm volatile("std 11,%0" : "=Q" (state->fprs[11]));
43 			asm volatile("std 12,%0" : "=Q" (state->fprs[12]));
44 			asm volatile("std 13,%0" : "=Q" (state->fprs[13]));
45 			asm volatile("std 14,%0" : "=Q" (state->fprs[14]));
46 			asm volatile("std 15,%0" : "=Q" (state->fprs[15]));
47 		}
48 		return;
49 	}
50 
51 	/* Test and save vector registers */
52 	asm volatile (
53 		/*
54 		 * Test if any vector register must be saved and, if so,
55 		 * test if all register can be saved.
56 		 */
57 		"	la	1,%[vxrs]\n"	/* load save area */
58 		"	tmll	%[m],30\n"	/* KERNEL_VXR */
59 		"	jz	7f\n"		/* no work -> done */
60 		"	jo	5f\n"		/* -> save V0..V31 */
61 		/*
62 		 * Test for special case KERNEL_FPU_MID only. In this
63 		 * case a vstm V8..V23 is the best instruction
64 		 */
65 		"	chi	%[m],12\n"	/* KERNEL_VXR_MID */
66 		"	jne	0f\n"		/* -> save V8..V23 */
67 		"	VSTM	8,23,128,1\n"	/* vstm %v8,%v23,128(%r1) */
68 		"	j	7f\n"
69 		/* Test and save the first half of 16 vector registers */
70 		"0:	tmll	%[m],6\n"	/* KERNEL_VXR_LOW */
71 		"	jz	3f\n"		/* -> KERNEL_VXR_HIGH */
72 		"	jo	2f\n"		/* 11 -> save V0..V15 */
73 		"	brc	2,1f\n"		/* 10 -> save V8..V15 */
74 		"	VSTM	0,7,0,1\n"	/* vstm %v0,%v7,0(%r1) */
75 		"	j	3f\n"
76 		"1:	VSTM	8,15,128,1\n"	/* vstm %v8,%v15,128(%r1) */
77 		"	j	3f\n"
78 		"2:	VSTM	0,15,0,1\n"	/* vstm %v0,%v15,0(%r1) */
79 		/* Test and save the second half of 16 vector registers */
80 		"3:	tmll	%[m],24\n"	/* KERNEL_VXR_HIGH */
81 		"	jz	7f\n"
82 		"	jo	6f\n"		/* 11 -> save V16..V31 */
83 		"	brc	2,4f\n"		/* 10 -> save V24..V31 */
84 		"	VSTM	16,23,256,1\n"	/* vstm %v16,%v23,256(%r1) */
85 		"	j	7f\n"
86 		"4:	VSTM	24,31,384,1\n"	/* vstm %v24,%v31,384(%r1) */
87 		"	j	7f\n"
88 		"5:	VSTM	0,15,0,1\n"	/* vstm %v0,%v15,0(%r1) */
89 		"6:	VSTM	16,31,256,1\n"	/* vstm %v16,%v31,256(%r1) */
90 		"7:"
91 		: [vxrs] "=Q" (*(struct vx_array *) &state->vxrs)
92 		: [m] "d" (flags)
93 		: "1", "cc");
94 }
95 EXPORT_SYMBOL(__kernel_fpu_begin);
96 
__kernel_fpu_end(struct kernel_fpu * state,u32 flags)97 void __kernel_fpu_end(struct kernel_fpu *state, u32 flags)
98 {
99 	/*
100 	 * Limit the restore to the FPU/vector registers of the
101 	 * previous context that have been overwritte by the
102 	 * current context
103 	 */
104 	flags &= state->mask;
105 
106 	if (flags & KERNEL_FPC)
107 		/* Restore floating-point controls */
108 		asm volatile("lfpc %0" : : "Q" (state->fpc));
109 
110 	if (!MACHINE_HAS_VX) {
111 		if (flags & KERNEL_VXR_V0V7) {
112 			/* Restore floating-point registers */
113 			asm volatile("ld 0,%0" : : "Q" (state->fprs[0]));
114 			asm volatile("ld 1,%0" : : "Q" (state->fprs[1]));
115 			asm volatile("ld 2,%0" : : "Q" (state->fprs[2]));
116 			asm volatile("ld 3,%0" : : "Q" (state->fprs[3]));
117 			asm volatile("ld 4,%0" : : "Q" (state->fprs[4]));
118 			asm volatile("ld 5,%0" : : "Q" (state->fprs[5]));
119 			asm volatile("ld 6,%0" : : "Q" (state->fprs[6]));
120 			asm volatile("ld 7,%0" : : "Q" (state->fprs[7]));
121 			asm volatile("ld 8,%0" : : "Q" (state->fprs[8]));
122 			asm volatile("ld 9,%0" : : "Q" (state->fprs[9]));
123 			asm volatile("ld 10,%0" : : "Q" (state->fprs[10]));
124 			asm volatile("ld 11,%0" : : "Q" (state->fprs[11]));
125 			asm volatile("ld 12,%0" : : "Q" (state->fprs[12]));
126 			asm volatile("ld 13,%0" : : "Q" (state->fprs[13]));
127 			asm volatile("ld 14,%0" : : "Q" (state->fprs[14]));
128 			asm volatile("ld 15,%0" : : "Q" (state->fprs[15]));
129 		}
130 		return;
131 	}
132 
133 	/* Test and restore (load) vector registers */
134 	asm volatile (
135 		/*
136 		 * Test if any vector register must be loaded and, if so,
137 		 * test if all registers can be loaded at once.
138 		 */
139 		"	la	1,%[vxrs]\n"	/* load restore area */
140 		"	tmll	%[m],30\n"	/* KERNEL_VXR */
141 		"	jz	7f\n"		/* no work -> done */
142 		"	jo	5f\n"		/* -> restore V0..V31 */
143 		/*
144 		 * Test for special case KERNEL_FPU_MID only. In this
145 		 * case a vlm V8..V23 is the best instruction
146 		 */
147 		"	chi	%[m],12\n"	/* KERNEL_VXR_MID */
148 		"	jne	0f\n"		/* -> restore V8..V23 */
149 		"	VLM	8,23,128,1\n"	/* vlm %v8,%v23,128(%r1) */
150 		"	j	7f\n"
151 		/* Test and restore the first half of 16 vector registers */
152 		"0:	tmll	%[m],6\n"	/* KERNEL_VXR_LOW */
153 		"	jz	3f\n"		/* -> KERNEL_VXR_HIGH */
154 		"	jo	2f\n"		/* 11 -> restore V0..V15 */
155 		"	brc	2,1f\n"		/* 10 -> restore V8..V15 */
156 		"	VLM	0,7,0,1\n"	/* vlm %v0,%v7,0(%r1) */
157 		"	j	3f\n"
158 		"1:	VLM	8,15,128,1\n"	/* vlm %v8,%v15,128(%r1) */
159 		"	j	3f\n"
160 		"2:	VLM	0,15,0,1\n"	/* vlm %v0,%v15,0(%r1) */
161 		/* Test and restore the second half of 16 vector registers */
162 		"3:	tmll	%[m],24\n"	/* KERNEL_VXR_HIGH */
163 		"	jz	7f\n"
164 		"	jo	6f\n"		/* 11 -> restore V16..V31 */
165 		"	brc	2,4f\n"		/* 10 -> restore V24..V31 */
166 		"	VLM	16,23,256,1\n"	/* vlm %v16,%v23,256(%r1) */
167 		"	j	7f\n"
168 		"4:	VLM	24,31,384,1\n"	/* vlm %v24,%v31,384(%r1) */
169 		"	j	7f\n"
170 		"5:	VLM	0,15,0,1\n"	/* vlm %v0,%v15,0(%r1) */
171 		"6:	VLM	16,31,256,1\n"	/* vlm %v16,%v31,256(%r1) */
172 		"7:"
173 		: [vxrs] "=Q" (*(struct vx_array *) &state->vxrs)
174 		: [m] "d" (flags)
175 		: "1", "cc");
176 }
177 EXPORT_SYMBOL(__kernel_fpu_end);
178