[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 <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>

1 files changed, 0 insertions, 163 deletions

diff --git a/arch/ppc/kernel/head.S b/arch/ppc/kernel/head.S
index 1a89a71e0acc..a931d773715f 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
@@ -1016,42 +889,6 @@ giveup_altivec:
 #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.
  */