From 443a848cd30eb5bb5c1038e6371d83404775dcfc Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Sun, 1 May 2005 08:58:40 -0700 Subject: [PATCH] ppc32: refactor FPU exception handling Moved common FPU exception handling code out of head.S so it can be used by several of the sub-architectures that might of a full PowerPC FPU. Also, uses new CONFIG_PPC_FPU define to fix alignment exception handling for floating point load/store instructions to only occur if we have a hardware FPU. Signed-off-by: Jason McMullan Signed-off-by: Kumar Gala Signed-off-by: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ppc/kernel/head.S | 163 ------------------------------------------------- 1 file changed, 163 deletions(-) (limited to 'arch/ppc/kernel/head.S') diff --git a/arch/ppc/kernel/head.S b/arch/ppc/kernel/head.S index 1a89a71e0ac..a931d773715 100644 --- a/arch/ppc/kernel/head.S +++ b/arch/ppc/kernel/head.S @@ -775,133 +775,6 @@ InstructionSegment: EXC_XFER_STD(0x480, UnknownException) #endif /* CONFIG_PPC64BRIDGE */ -/* - * 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. - */ -load_up_fpu: - mfmsr r5 - ori r5,r5,MSR_FP -#ifdef CONFIG_PPC64BRIDGE - clrldi r5,r5,1 /* turn off 64-bit mode */ -#endif /* CONFIG_PPC64BRIDGE */ - 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 - tophys(r6,0) /* get __pa constant */ - addis r3,r6,last_task_used_math@ha - lwz r4,last_task_used_math@l(r3) - cmpwi 0,r4,0 - beq 1f - add r4,r4,r6 - addi r4,r4,THREAD /* want last_task_used_math->thread */ - SAVE_32FPRS(0, r4) - mffs fr0 - stfd fr0,THREAD_FPSCR-4(r4) - lwz r5,PT_REGS(r4) - add r5,r5,r6 - lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5) - li r10,MSR_FP|MSR_FE0|MSR_FE1 - andc r4,r4,r10 /* disable FP for previous task */ - stw r4,_MSR-STACK_FRAME_OVERHEAD(r5) -1: -#endif /* CONFIG_SMP */ - /* enable use of FP after return */ - 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 - lfd fr0,THREAD_FPSCR-4(r5) - mtfsf 0xff,fr0 - REST_32FPRS(0, r5) -#ifndef CONFIG_SMP - subi r4,r5,THREAD - sub r4,r4,r6 - stw r4,last_task_used_math@l(r3) -#endif /* CONFIG_SMP */ - /* restore registers and return */ - /* we haven't used ctr or xer or lr */ - /* fall through to fast_exception_return */ - - .globl fast_exception_return -fast_exception_return: - andi. r10,r9,MSR_RI /* check for recoverable interrupt */ - beq 1f /* if not, we've got problems */ -2: REST_4GPRS(3, r11) - lwz r10,_CCR(r11) - REST_GPR(1, r11) - mtcr r10 - lwz r10,_LINK(r11) - mtlr r10 - REST_GPR(10, r11) - mtspr SPRN_SRR1,r9 - mtspr SPRN_SRR0,r12 - REST_GPR(9, r11) - REST_GPR(12, r11) - lwz r11,GPR11(r11) - SYNC - RFI - -/* check if the exception happened in a restartable section */ -1: lis r3,exc_exit_restart_end@ha - addi r3,r3,exc_exit_restart_end@l - cmplw r12,r3 - bge 3f - lis r4,exc_exit_restart@ha - addi r4,r4,exc_exit_restart@l - cmplw r12,r4 - blt 3f - lis r3,fee_restarts@ha - tophys(r3,r3) - lwz r5,fee_restarts@l(r3) - addi r5,r5,1 - stw r5,fee_restarts@l(r3) - mr r12,r4 /* restart at exc_exit_restart */ - b 2b - - .comm fee_restarts,4 - -/* aargh, a nonrecoverable interrupt, panic */ -/* aargh, we don't know which trap this is */ -/* but the 601 doesn't implement the RI bit, so assume it's OK */ -3: -BEGIN_FTR_SECTION - b 2b -END_FTR_SECTION_IFSET(CPU_FTR_601) - li r10,-1 - stw r10,TRAP(r11) - addi r3,r1,STACK_FRAME_OVERHEAD - li r10,MSR_KERNEL - bl transfer_to_handler_full - .long nonrecoverable_exception - .long ret_from_except - -/* - * FP unavailable trap from kernel - print a message, but let - * the task use FP in the kernel until it returns to user mode. - */ -KernelFP: - lwz r3,_MSR(r1) - ori r3,r3,MSR_FP - stw r3,_MSR(r1) /* enable use of FP after return */ - lis r3,86f@h - ori r3,r3,86f@l - mr r4,r2 /* current */ - lwz r5,_NIP(r1) - bl printk - b ret_from_except -86: .string "floating point used in kernel (task=%p, pc=%x)\n" - .align 4,0 - #ifdef CONFIG_ALTIVEC /* Note that the AltiVec support is closely modeled after the FP * support. Changes to one are likely to be applicable to the @@ -1015,42 +888,6 @@ giveup_altivec: blr #endif /* CONFIG_ALTIVEC */ -/* - * 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. - */ - .globl giveup_fpu -giveup_fpu: - mfmsr r5 - ori r5,r5,MSR_FP - SYNC_601 - ISYNC_601 - MTMSRD(r5) /* enable use of fpu now */ - SYNC_601 - isync - cmpwi 0,r3,0 - beqlr- /* if no previous owner, done */ - addi r3,r3,THREAD /* want THREAD of task */ - lwz r5,PT_REGS(r3) - cmpwi 0,r5,0 - SAVE_32FPRS(0, r3) - mffs fr0 - stfd fr0,THREAD_FPSCR-4(r3) - beq 1f - lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5) - li r3,MSR_FP|MSR_FE0|MSR_FE1 - andc r4,r4,r3 /* disable FP for previous task */ - stw r4,_MSR-STACK_FRAME_OVERHEAD(r5) -1: -#ifndef CONFIG_SMP - li r5,0 - lis r4,last_task_used_math@ha - stw r5,last_task_used_math@l(r4) -#endif /* CONFIG_SMP */ - blr - /* * This code is jumped to from the startup code to copy * the kernel image to physical address 0. -- cgit v1.2.3