Commit | Line | Data |
---|---|---|
14cf11af PM |
1 | /* |
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. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or | |
6 | * modify it under the terms of the GNU General Public License | |
7 | * as published by the Free Software Foundation; either version | |
8 | * 2 of the License, or (at your option) any later version. | |
9 | * | |
10 | */ | |
11 | ||
12 | #include <linux/config.h> | |
13 | #include <asm/processor.h> | |
14 | #include <asm/page.h> | |
15 | #include <asm/mmu.h> | |
16 | #include <asm/pgtable.h> | |
17 | #include <asm/cputable.h> | |
18 | #include <asm/cache.h> | |
19 | #include <asm/thread_info.h> | |
20 | #include <asm/ppc_asm.h> | |
21 | #include <asm/asm-offsets.h> | |
22 | ||
23 | /* | |
24 | * This task wants to use the FPU now. | |
25 | * On UP, disable FP for the task which had the FPU previously, | |
26 | * and save its floating-point registers in its thread_struct. | |
27 | * Load up this task's FP registers from its thread_struct, | |
28 | * enable the FPU for the current task and return to the task. | |
29 | */ | |
30 | .globl load_up_fpu | |
31 | load_up_fpu: | |
32 | mfmsr r5 | |
33 | ori r5,r5,MSR_FP | |
34 | #ifdef CONFIG_PPC64BRIDGE | |
35 | clrldi r5,r5,1 /* turn off 64-bit mode */ | |
36 | #endif /* CONFIG_PPC64BRIDGE */ | |
37 | SYNC | |
38 | MTMSRD(r5) /* enable use of fpu now */ | |
39 | isync | |
40 | /* | |
41 | * For SMP, we don't do lazy FPU switching because it just gets too | |
42 | * horrendously complex, especially when a task switches from one CPU | |
43 | * to another. Instead we call giveup_fpu in switch_to. | |
44 | */ | |
45 | #ifndef CONFIG_SMP | |
46 | tophys(r6,0) /* get __pa constant */ | |
47 | addis r3,r6,last_task_used_math@ha | |
48 | lwz r4,last_task_used_math@l(r3) | |
49 | cmpwi 0,r4,0 | |
50 | beq 1f | |
51 | add r4,r4,r6 | |
52 | addi r4,r4,THREAD /* want last_task_used_math->thread */ | |
53 | SAVE_32FPRS(0, r4) | |
54 | mffs fr0 | |
55 | stfd fr0,THREAD_FPSCR-4(r4) | |
56 | lwz r5,PT_REGS(r4) | |
57 | add r5,r5,r6 | |
58 | lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5) | |
59 | li r10,MSR_FP|MSR_FE0|MSR_FE1 | |
60 | andc r4,r4,r10 /* disable FP for previous task */ | |
61 | stw r4,_MSR-STACK_FRAME_OVERHEAD(r5) | |
62 | 1: | |
63 | #endif /* CONFIG_SMP */ | |
64 | /* enable use of FP after return */ | |
65 | mfspr r5,SPRN_SPRG3 /* current task's THREAD (phys) */ | |
66 | lwz r4,THREAD_FPEXC_MODE(r5) | |
67 | ori r9,r9,MSR_FP /* enable FP for current */ | |
68 | or r9,r9,r4 | |
69 | lfd fr0,THREAD_FPSCR-4(r5) | |
70 | mtfsf 0xff,fr0 | |
71 | REST_32FPRS(0, r5) | |
72 | #ifndef CONFIG_SMP | |
73 | subi r4,r5,THREAD | |
74 | sub r4,r4,r6 | |
75 | stw r4,last_task_used_math@l(r3) | |
76 | #endif /* CONFIG_SMP */ | |
77 | /* restore registers and return */ | |
78 | /* we haven't used ctr or xer or lr */ | |
79 | b fast_exception_return | |
80 | ||
81 | /* | |
82 | * FP unavailable trap from kernel - print a message, but let | |
83 | * the task use FP in the kernel until it returns to user mode. | |
84 | */ | |
85 | .globl KernelFP | |
86 | KernelFP: | |
87 | lwz r3,_MSR(r1) | |
88 | ori r3,r3,MSR_FP | |
89 | stw r3,_MSR(r1) /* enable use of FP after return */ | |
90 | lis r3,86f@h | |
91 | ori r3,r3,86f@l | |
92 | mr r4,r2 /* current */ | |
93 | lwz r5,_NIP(r1) | |
94 | bl printk | |
95 | b ret_from_except | |
96 | 86: .string "floating point used in kernel (task=%p, pc=%x)\n" | |
97 | .align 4,0 | |
98 | ||
99 | /* | |
100 | * giveup_fpu(tsk) | |
101 | * Disable FP for the task given as the argument, | |
102 | * and save the floating-point registers in its thread_struct. | |
103 | * Enables the FPU for use in the kernel on return. | |
104 | */ | |
105 | .globl giveup_fpu | |
106 | giveup_fpu: | |
107 | mfmsr r5 | |
108 | ori r5,r5,MSR_FP | |
109 | SYNC_601 | |
110 | ISYNC_601 | |
111 | MTMSRD(r5) /* enable use of fpu now */ | |
112 | SYNC_601 | |
113 | isync | |
114 | cmpwi 0,r3,0 | |
115 | beqlr- /* if no previous owner, done */ | |
116 | addi r3,r3,THREAD /* want THREAD of task */ | |
117 | lwz r5,PT_REGS(r3) | |
118 | cmpwi 0,r5,0 | |
119 | SAVE_32FPRS(0, r3) | |
120 | mffs fr0 | |
121 | stfd fr0,THREAD_FPSCR-4(r3) | |
122 | beq 1f | |
123 | lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5) | |
124 | li r3,MSR_FP|MSR_FE0|MSR_FE1 | |
125 | andc r4,r4,r3 /* disable FP for previous task */ | |
126 | stw r4,_MSR-STACK_FRAME_OVERHEAD(r5) | |
127 | 1: | |
128 | #ifndef CONFIG_SMP | |
129 | li r5,0 | |
130 | lis r4,last_task_used_math@ha | |
131 | stw r5,last_task_used_math@l(r4) | |
132 | #endif /* CONFIG_SMP */ | |
133 | blr |