2 * FPU support code, moved here from head.S so that it can be used
3 * by chips which use other head-whatever.S files.
5 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
6 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
7 * Copyright (C) 1996 Paul Mackerras.
8 * Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
20 #include <asm/pgtable.h>
21 #include <asm/cputable.h>
22 #include <asm/cache.h>
23 #include <asm/thread_info.h>
24 #include <asm/ppc_asm.h>
25 #include <asm/asm-offsets.h>
26 #include <asm/ptrace.h>
29 #define __REST_32FPVSRS(n,c,base) \
32 END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
33 REST_32FPRS(n,base); \
35 2: REST_32VSRS(n,c,base); \
38 #define __SAVE_32FPVSRS(n,c,base) \
41 END_FTR_SECTION_IFSET(CPU_FTR_VSX); \
42 SAVE_32FPRS(n,base); \
44 2: SAVE_32VSRS(n,c,base); \
47 #define __REST_32FPVSRS(n,b,base) REST_32FPRS(n, base)
48 #define __SAVE_32FPVSRS(n,b,base) SAVE_32FPRS(n, base)
50 #define REST_32FPVSRS(n,c,base) __REST_32FPVSRS(n,__REG_##c,__REG_##base)
51 #define SAVE_32FPVSRS(n,c,base) __SAVE_32FPVSRS(n,__REG_##c,__REG_##base)
53 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
54 /* void do_load_up_transact_fpu(struct thread_struct *thread)
56 * This is similar to load_up_fpu but for the transactional version of the FP
57 * register set. It doesn't mess with the task MSR or valid flags.
58 * Furthermore, we don't do lazy FP with TM currently.
60 _GLOBAL(do_load_up_transact_fpu)
66 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
71 addi r7,r3,THREAD_TRANSACT_FPSTATE
72 lfd fr0,FPSTATE_FPSCR(r7)
74 REST_32FPVSRS(0, R4, R7)
76 /* FP/VSX off again */
81 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
84 * Load state from memory into FP registers including FPSCR.
85 * Assumes the caller has enabled FP in the MSR.
87 _GLOBAL(load_fp_state)
88 lfd fr0,FPSTATE_FPSCR(r3)
90 REST_32FPVSRS(0, R4, R3)
94 * Store FP state into memory, including FPSCR
95 * Assumes the caller has enabled FP in the MSR.
97 _GLOBAL(store_fp_state)
98 SAVE_32FPVSRS(0, R4, R3)
100 stfd fr0,FPSTATE_FPSCR(r3)
104 * This task wants to use the FPU now.
105 * On UP, disable FP for the task which had the FPU previously,
106 * and save its floating-point registers in its thread_struct.
107 * Load up this task's FP registers from its thread_struct,
108 * enable the FPU for the current task and return to the task.
116 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
119 MTMSRD(r5) /* enable use of fpu now */
122 * For SMP, we don't do lazy FPU switching because it just gets too
123 * horrendously complex, especially when a task switches from one CPU
124 * to another. Instead we call giveup_fpu in switch_to.
127 LOAD_REG_ADDRBASE(r3, last_task_used_math)
129 PPC_LL r4,ADDROFF(last_task_used_math)(r3)
133 addi r4,r4,THREAD /* want last_task_used_math->thread */
134 addi r8,r4,THREAD_FPSTATE
135 SAVE_32FPVSRS(0, R5, R8)
137 stfd fr0,FPSTATE_FPSCR(r8)
138 PPC_LL r5,PT_REGS(r4)
140 PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
141 li r10,MSR_FP|MSR_FE0|MSR_FE1
142 andc r4,r4,r10 /* disable FP for previous task */
143 PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
145 #endif /* CONFIG_SMP */
146 /* enable use of FP after return */
148 mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
149 lwz r4,THREAD_FPEXC_MODE(r5)
150 ori r9,r9,MSR_FP /* enable FP for current */
153 ld r4,PACACURRENT(r13)
154 addi r5,r4,THREAD /* Get THREAD */
155 lwz r4,THREAD_FPEXC_MODE(r5)
160 addi r7,r5,THREAD_FPSTATE
161 lfd fr0,FPSTATE_FPSCR(r7)
163 REST_32FPVSRS(0, R4, R7)
167 PPC_STL r4,ADDROFF(last_task_used_math)(r3)
168 #endif /* CONFIG_SMP */
169 /* restore registers and return */
170 /* we haven't used ctr or xer or lr */
175 * Disable FP for the task given as the argument,
176 * and save the floating-point registers in its thread_struct.
177 * Enables the FPU for use in the kernel on return.
185 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
189 MTMSRD(r5) /* enable use of fpu now */
193 beqlr- /* if no previous owner, done */
194 addi r3,r3,THREAD /* want THREAD of task */
195 PPC_LL r6,THREAD_FPSAVEAREA(r3)
196 PPC_LL r5,PT_REGS(r3)
199 addi r6,r3,THREAD_FPSTATE
201 SAVE_32FPVSRS(0, R4, R6)
203 stfd fr0,FPSTATE_FPSCR(r6)
205 PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
206 li r3,MSR_FP|MSR_FE0|MSR_FE1
210 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
212 andc r4,r4,r3 /* disable FP for previous task */
213 PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
217 LOAD_REG_ADDRBASE(r4,last_task_used_math)
218 PPC_STL r5,ADDROFF(last_task_used_math)(r4)
219 #endif /* CONFIG_SMP */
223 * These are used in the alignment trap handler when emulating
224 * single-precision loads and stores.