projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 443a848c 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> | |
| 0013a854 | 21 | #include <asm/asm-offsets.h> |
| 443a848c PM |
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 |