443a848cd3
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 <jason.mcmullan@timesys.com> Signed-off-by: Kumar Gala <kumar.gala@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
133 lines
3.5 KiB
ArmAsm
133 lines
3.5 KiB
ArmAsm
/*
|
|
* 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/processor.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/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.
|
|
*/
|
|
.globl load_up_fpu
|
|
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 */
|
|
b fast_exception_return
|
|
|
|
/*
|
|
* FP unavailable trap from kernel - print a message, but let
|
|
* the task use FP in the kernel until it returns to user mode.
|
|
*/
|
|
.globl KernelFP
|
|
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
|
|
|
|
/*
|
|
* 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
|