1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * FPU support code, moved here from head.S so that it can be used
4 * by chips which use other head-whatever.S files.
6 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
7 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
8 * Copyright (C) 1996 Paul Mackerras.
9 * Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
12 #include <linux/export.h>
16 #include <asm/cputable.h>
17 #include <asm/cache.h>
18 #include <asm/thread_info.h>
19 #include <asm/ppc_asm.h>
20 #include <asm/asm-offsets.h>
21 #include <asm/ptrace.h>
22 #include <asm/asm-compat.h>
23 #include <asm/feature-fixups.h>
26 #define __REST_1FPVSR(n,c,base) \
29 END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
32 2: REST_VSR(n,c,base); \
35 #define __REST_32FPVSRS(n,c,base) \
38 END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
39 REST_32FPRS(n,base); \
41 2: REST_32VSRS(n,c,base); \
44 #define __SAVE_32FPVSRS(n,c,base) \
47 END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
48 SAVE_32FPRS(n,base); \
50 2: SAVE_32VSRS(n,c,base); \
53 #define __REST_1FPVSR(n,b,base) REST_FPR(n, base)
54 #define __REST_32FPVSRS(n,b,base) REST_32FPRS(n, base)
55 #define __SAVE_32FPVSRS(n,b,base) SAVE_32FPRS(n, base)
57 #define REST_1FPVSR(n,c,base) __REST_1FPVSR(n,__REG_##c,__REG_##base)
58 #define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base)
59 #define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base)
62 * Load state from memory into FP registers including FPSCR.
63 * Assumes the caller has enabled FP in the MSR.
65 _GLOBAL(load_fp_state)
66 lfd fr0,FPSTATE_FPSCR(r3)
68 REST_32FPVSRS(0, R4, R3)
70 EXPORT_SYMBOL(load_fp_state)
71 _ASM_NOKPROBE_SYMBOL(load_fp_state); /* used by restore_math */
74 * Store FP state into memory, including FPSCR
75 * Assumes the caller has enabled FP in the MSR.
77 _GLOBAL(store_fp_state)
78 SAVE_32FPVSRS(0, R4, R3)
80 stfd fr0,FPSTATE_FPSCR(r3)
81 REST_1FPVSR(0, R4, R3)
83 EXPORT_SYMBOL(store_fp_state)
86 * This task wants to use the FPU now.
87 * On UP, disable FP for the task which had the FPU previously,
88 * and save its floating-point registers in its thread_struct.
89 * Load up this task's FP registers from its thread_struct,
90 * enable the FPU for the current task and return to the task.
91 * Note that on 32-bit this can only use registers that will be
92 * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
96 #ifdef CONFIG_PPC_BOOK3S_64
97 /* interrupt doesn't set MSR[RI] and HPT can fault on current access */
98 ori r5,r5,MSR_FP|MSR_RI
105 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
107 MTMSRD(r5) /* enable use of fpu now */
109 /* enable use of FP after return */
112 lwz r4,THREAD_FPEXC_MODE(r5)
113 ori r9,r9,MSR_FP /* enable FP for current */
116 ld r4,PACACURRENT(r13)
117 addi r5,r4,THREAD /* Get THREAD */
118 lwz r4,THREAD_FPEXC_MODE(r5)
122 #ifdef CONFIG_PPC_BOOK3S_64
124 stb r4,PACASRR_VALID(r13)
128 stb r4,THREAD_LOAD_FP(r5)
129 addi r10,r5,THREAD_FPSTATE
130 lfd fr0,FPSTATE_FPSCR(r10)
132 REST_32FPVSRS(0, R4, R10)
133 /* restore registers and return */
134 /* we haven't used ctr or xer or lr */
136 _ASM_NOKPROBE_SYMBOL(load_up_fpu)
140 * Save the floating-point registers in its thread_struct.
141 * Enables the FPU for use in the kernel on return.
144 addi r3,r3,THREAD /* want THREAD of task */
145 PPC_LL r6,THREAD_FPSAVEAREA(r3)
146 PPC_LL r5,PT_REGS(r3)
149 addi r6,r3,THREAD_FPSTATE
150 2: SAVE_32FPVSRS(0, R4, R6)
152 stfd fr0,FPSTATE_FPSCR(r6)
153 REST_1FPVSR(0, R4, R6)