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.
109 * Note that on 32-bit this can only use registers that will be
110 * restored by fast_exception_return, i.e. r3 - r6, r10 and r11.
118 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
121 MTMSRD(r5) /* enable use of fpu now */
124 * For SMP, we don't do lazy FPU switching because it just gets too
125 * horrendously complex, especially when a task switches from one CPU
126 * to another. Instead we call giveup_fpu in switch_to.
129 LOAD_REG_ADDRBASE(r3, last_task_used_math)
131 PPC_LL r4,ADDROFF(last_task_used_math)(r3)
135 addi r4,r4,THREAD /* want last_task_used_math->thread */
136 addi r10,r4,THREAD_FPSTATE
137 SAVE_32FPVSRS(0, R5, R10)
139 stfd fr0,FPSTATE_FPSCR(r10)
140 PPC_LL r5,PT_REGS(r4)
142 PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
143 li r10,MSR_FP|MSR_FE0|MSR_FE1
144 andc r4,r4,r10 /* disable FP for previous task */
145 PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
147 #endif /* CONFIG_SMP */
148 /* enable use of FP after return */
150 mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */
151 lwz r4,THREAD_FPEXC_MODE(r5)
152 ori r9,r9,MSR_FP /* enable FP for current */
155 ld r4,PACACURRENT(r13)
156 addi r5,r4,THREAD /* Get THREAD */
157 lwz r4,THREAD_FPEXC_MODE(r5)
162 addi r10,r5,THREAD_FPSTATE
163 lfd fr0,FPSTATE_FPSCR(r10)
165 REST_32FPVSRS(0, R4, R10)
169 PPC_STL r4,ADDROFF(last_task_used_math)(r3)
170 #endif /* CONFIG_SMP */
171 /* restore registers and return */
172 /* we haven't used ctr or xer or lr */
177 * Disable FP for the task given as the argument,
178 * and save the floating-point registers in its thread_struct.
179 * Enables the FPU for use in the kernel on return.
187 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
191 MTMSRD(r5) /* enable use of fpu now */
195 beqlr- /* if no previous owner, done */
196 addi r3,r3,THREAD /* want THREAD of task */
197 PPC_LL r6,THREAD_FPSAVEAREA(r3)
198 PPC_LL r5,PT_REGS(r3)
201 addi r6,r3,THREAD_FPSTATE
203 SAVE_32FPVSRS(0, R4, R6)
205 stfd fr0,FPSTATE_FPSCR(r6)
207 PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
208 li r3,MSR_FP|MSR_FE0|MSR_FE1
212 END_FTR_SECTION_IFSET(CPU_FTR_VSX)
214 andc r4,r4,r3 /* disable FP for previous task */
215 PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
219 LOAD_REG_ADDRBASE(r4,last_task_used_math)
220 PPC_STL r5,ADDROFF(last_task_used_math)(r4)
221 #endif /* CONFIG_SMP */
225 * These are used in the alignment trap handler when emulating
226 * single-precision loads and stores.