| /* |
| * FPU support code, moved here from head.S so that it can be used |
| * by chips which use other head-whatever.S files. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| */ |
| |
| #include <linux/config.h> |
| #include <asm/reg.h> |
| #include <asm/page.h> |
| #include <asm/mmu.h> |
| #include <asm/pgtable.h> |
| #include <asm/cputable.h> |
| #include <asm/cache.h> |
| #include <asm/thread_info.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/asm-offsets.h> |
| |
| /* |
| * This task wants to use the FPU now. |
| * On UP, disable FP for the task which had the FPU previously, |
| * and save its floating-point registers in its thread_struct. |
| * Load up this task's FP registers from its thread_struct, |
| * enable the FPU for the current task and return to the task. |
| */ |
| _GLOBAL(load_up_fpu) |
| mfmsr r5 |
| ori r5,r5,MSR_FP |
| SYNC |
| MTMSRD(r5) /* enable use of fpu now */ |
| isync |
| /* |
| * For SMP, we don't do lazy FPU switching because it just gets too |
| * horrendously complex, especially when a task switches from one CPU |
| * to another. Instead we call giveup_fpu in switch_to. |
| */ |
| #ifndef CONFIG_SMP |
| LOADBASE(r3, last_task_used_math) |
| tophys(r3,r3) |
| LDL r4,OFF(last_task_used_math)(r3) |
| CMPI 0,r4,0 |
| beq 1f |
| tophys(r4,r4) |
| addi r4,r4,THREAD /* want last_task_used_math->thread */ |
| SAVE_32FPRS(0, r4) |
| mffs fr0 |
| stfd fr0,THREAD_FPSCR-4(r4) |
| LDL r5,PT_REGS(r4) |
| tophys(r5,r5) |
| LDL r4,_MSR-STACK_FRAME_OVERHEAD(r5) |
| li r10,MSR_FP|MSR_FE0|MSR_FE1 |
| andc r4,r4,r10 /* disable FP for previous task */ |
| STL r4,_MSR-STACK_FRAME_OVERHEAD(r5) |
| 1: |
| #endif /* CONFIG_SMP */ |
| /* enable use of FP after return */ |
| #ifdef CONFIG_PPC32 |
| mfspr r5,SPRN_SPRG3 /* current task's THREAD (phys) */ |
| lwz r4,THREAD_FPEXC_MODE(r5) |
| ori r9,r9,MSR_FP /* enable FP for current */ |
| or r9,r9,r4 |
| #else |
| ld r4,PACACURRENT(r13) |
| addi r5,r4,THREAD /* Get THREAD */ |
| ld r4,THREAD_FPEXC_MODE(r5) |
| ori r12,r12,MSR_FP |
| or r12,r12,r4 |
| std r12,_MSR(r1) |
| #endif |
| lfd fr0,THREAD_FPSCR-4(r5) |
| mtfsf 0xff,fr0 |
| REST_32FPRS(0, r5) |
| #ifndef CONFIG_SMP |
| subi r4,r5,THREAD |
| tovirt(r4,r4) |
| STL r4,OFF(last_task_used_math)(r3) |
| #endif /* CONFIG_SMP */ |
| /* restore registers and return */ |
| /* we haven't used ctr or xer or lr */ |
| b fast_exception_return |
| |
| /* |
| * giveup_fpu(tsk) |
| * Disable FP for the task given as the argument, |
| * and save the floating-point registers in its thread_struct. |
| * Enables the FPU for use in the kernel on return. |
| */ |
| _GLOBAL(giveup_fpu) |
| mfmsr r5 |
| ori r5,r5,MSR_FP |
| SYNC_601 |
| ISYNC_601 |
| MTMSRD(r5) /* enable use of fpu now */ |
| SYNC_601 |
| isync |
| CMPI 0,r3,0 |
| beqlr- /* if no previous owner, done */ |
| addi r3,r3,THREAD /* want THREAD of task */ |
| LDL r5,PT_REGS(r3) |
| CMPI 0,r5,0 |
| SAVE_32FPRS(0, r3) |
| mffs fr0 |
| stfd fr0,THREAD_FPSCR-4(r3) |
| beq 1f |
| LDL r4,_MSR-STACK_FRAME_OVERHEAD(r5) |
| li r3,MSR_FP|MSR_FE0|MSR_FE1 |
| andc r4,r4,r3 /* disable FP for previous task */ |
| STL r4,_MSR-STACK_FRAME_OVERHEAD(r5) |
| 1: |
| #ifndef CONFIG_SMP |
| li r5,0 |
| LOADBASE(r4,last_task_used_math) |
| STL r5,OFF(last_task_used_math)(r4) |
| #endif /* CONFIG_SMP */ |
| blr |
