Merge tag 'sched-urgent-2020-12-27' of git://git.kernel.org/pub/scm/linux/kernel...
[linux/fpc-iii.git] / arch / powerpc / kernel / fpu.S
blob3ff9a8fafa467c9d76b9b6d3605ed3884b45ccd9
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
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.
5  *
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).
10  */
12 #include <asm/reg.h>
13 #include <asm/page.h>
14 #include <asm/mmu.h>
15 #include <asm/cputable.h>
16 #include <asm/cache.h>
17 #include <asm/thread_info.h>
18 #include <asm/ppc_asm.h>
19 #include <asm/asm-offsets.h>
20 #include <asm/ptrace.h>
21 #include <asm/export.h>
22 #include <asm/asm-compat.h>
23 #include <asm/feature-fixups.h>
25 #ifdef CONFIG_VSX
26 #define __REST_32FPVSRS(n,c,base)                                       \
27 BEGIN_FTR_SECTION                                                       \
28         b       2f;                                                     \
29 END_FTR_SECTION_IFSET(CPU_FTR_VSX);                                     \
30         REST_32FPRS(n,base);                                            \
31         b       3f;                                                     \
32 2:      REST_32VSRS(n,c,base);                                          \
35 #define __SAVE_32FPVSRS(n,c,base)                                       \
36 BEGIN_FTR_SECTION                                                       \
37         b       2f;                                                     \
38 END_FTR_SECTION_IFSET(CPU_FTR_VSX);                                     \
39         SAVE_32FPRS(n,base);                                            \
40         b       3f;                                                     \
41 2:      SAVE_32VSRS(n,c,base);                                          \
43 #else
44 #define __REST_32FPVSRS(n,b,base)       REST_32FPRS(n, base)
45 #define __SAVE_32FPVSRS(n,b,base)       SAVE_32FPRS(n, base)
46 #endif
47 #define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base)
48 #define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base)
51  * Load state from memory into FP registers including FPSCR.
52  * Assumes the caller has enabled FP in the MSR.
53  */
54 _GLOBAL(load_fp_state)
55         lfd     fr0,FPSTATE_FPSCR(r3)
56         MTFSF_L(fr0)
57         REST_32FPVSRS(0, R4, R3)
58         blr
59 EXPORT_SYMBOL(load_fp_state)
60 _ASM_NOKPROBE_SYMBOL(load_fp_state); /* used by restore_math */
63  * Store FP state into memory, including FPSCR
64  * Assumes the caller has enabled FP in the MSR.
65  */
66 _GLOBAL(store_fp_state)
67         SAVE_32FPVSRS(0, R4, R3)
68         mffs    fr0
69         stfd    fr0,FPSTATE_FPSCR(r3)
70         blr
71 EXPORT_SYMBOL(store_fp_state)
74  * This task wants to use the FPU now.
75  * On UP, disable FP for the task which had the FPU previously,
76  * and save its floating-point registers in its thread_struct.
77  * Load up this task's FP registers from its thread_struct,
78  * enable the FPU for the current task and return to the task.
79  * Note that on 32-bit this can only use registers that will be
80  * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
81  */
82 _GLOBAL(load_up_fpu)
83         mfmsr   r5
84         ori     r5,r5,MSR_FP
85 #ifdef CONFIG_VSX
86 BEGIN_FTR_SECTION
87         oris    r5,r5,MSR_VSX@h
88 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
89 #endif
90         MTMSRD(r5)                      /* enable use of fpu now */
91         isync
92         /* enable use of FP after return */
93 #ifdef CONFIG_PPC32
94         mfspr   r5,SPRN_SPRG_THREAD     /* current task's THREAD (phys) */
95 #ifdef CONFIG_VMAP_STACK
96         tovirt(r5, r5)
97 #endif
98         lwz     r4,THREAD_FPEXC_MODE(r5)
99         ori     r9,r9,MSR_FP            /* enable FP for current */
100         or      r9,r9,r4
101 #else
102         ld      r4,PACACURRENT(r13)
103         addi    r5,r4,THREAD            /* Get THREAD */
104         lwz     r4,THREAD_FPEXC_MODE(r5)
105         ori     r12,r12,MSR_FP
106         or      r12,r12,r4
107         std     r12,_MSR(r1)
108 #endif
109         li      r4,1
110         stb     r4,THREAD_LOAD_FP(r5)
111         addi    r10,r5,THREAD_FPSTATE
112         lfd     fr0,FPSTATE_FPSCR(r10)
113         MTFSF_L(fr0)
114         REST_32FPVSRS(0, R4, R10)
115         /* restore registers and return */
116         /* we haven't used ctr or xer or lr */
117         blr
118 _ASM_NOKPROBE_SYMBOL(load_up_fpu)
121  * save_fpu(tsk)
122  * Save the floating-point registers in its thread_struct.
123  * Enables the FPU for use in the kernel on return.
124  */
125 _GLOBAL(save_fpu)
126         addi    r3,r3,THREAD            /* want THREAD of task */
127         PPC_LL  r6,THREAD_FPSAVEAREA(r3)
128         PPC_LL  r5,PT_REGS(r3)
129         PPC_LCMPI       0,r6,0
130         bne     2f
131         addi    r6,r3,THREAD_FPSTATE
132 2:      SAVE_32FPVSRS(0, R4, R6)
133         mffs    fr0
134         stfd    fr0,FPSTATE_FPSCR(r6)
135         blr