MN10300: Make the FPU operate in non-lazy mode under SMP
Make the FPU operate in non-lazy mode under SMP so that when the process that
is currently using the FPU migrates to a different CPU, we don't have to ping
its previous CPU to flush the FPU context.
Signed-off-by: Akira Takeuchi <takeuchi.akr@jp.panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@jp.panasonic.com>
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/arch/mn10300/kernel/fpu-low.S b/arch/mn10300/kernel/fpu-low.S
index 96cfd47..78df25c 100644
--- a/arch/mn10300/kernel/fpu-low.S
+++ b/arch/mn10300/kernel/fpu-low.S
@@ -8,25 +8,14 @@
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
+#include <linux/linkage.h>
#include <asm/cpu-regs.h>
+#include <asm/smp.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/frame.inc>
-###############################################################################
-#
-# void fpu_init_state(void)
-# - initialise the FPU
-#
-###############################################################################
- .globl fpu_init_state
- .type fpu_init_state,@function
-fpu_init_state:
- mov epsw,d0
- or EPSW_FE,epsw
-
-#ifdef CONFIG_MN10300_PROC_MN103E010
- nop
- nop
- nop
-#endif
+.macro FPU_INIT_STATE_ALL
fmov 0,fs0
fmov fs0,fs1
fmov fs0,fs2
@@ -60,7 +49,100 @@
fmov fs0,fs30
fmov fs0,fs31
fmov FPCR_INIT,fpcr
+.endm
+.macro FPU_SAVE_ALL areg,dreg
+ fmov fs0,(\areg+)
+ fmov fs1,(\areg+)
+ fmov fs2,(\areg+)
+ fmov fs3,(\areg+)
+ fmov fs4,(\areg+)
+ fmov fs5,(\areg+)
+ fmov fs6,(\areg+)
+ fmov fs7,(\areg+)
+ fmov fs8,(\areg+)
+ fmov fs9,(\areg+)
+ fmov fs10,(\areg+)
+ fmov fs11,(\areg+)
+ fmov fs12,(\areg+)
+ fmov fs13,(\areg+)
+ fmov fs14,(\areg+)
+ fmov fs15,(\areg+)
+ fmov fs16,(\areg+)
+ fmov fs17,(\areg+)
+ fmov fs18,(\areg+)
+ fmov fs19,(\areg+)
+ fmov fs20,(\areg+)
+ fmov fs21,(\areg+)
+ fmov fs22,(\areg+)
+ fmov fs23,(\areg+)
+ fmov fs24,(\areg+)
+ fmov fs25,(\areg+)
+ fmov fs26,(\areg+)
+ fmov fs27,(\areg+)
+ fmov fs28,(\areg+)
+ fmov fs29,(\areg+)
+ fmov fs30,(\areg+)
+ fmov fs31,(\areg+)
+ fmov fpcr,\dreg
+ mov \dreg,(\areg)
+.endm
+
+.macro FPU_RESTORE_ALL areg,dreg
+ fmov (\areg+),fs0
+ fmov (\areg+),fs1
+ fmov (\areg+),fs2
+ fmov (\areg+),fs3
+ fmov (\areg+),fs4
+ fmov (\areg+),fs5
+ fmov (\areg+),fs6
+ fmov (\areg+),fs7
+ fmov (\areg+),fs8
+ fmov (\areg+),fs9
+ fmov (\areg+),fs10
+ fmov (\areg+),fs11
+ fmov (\areg+),fs12
+ fmov (\areg+),fs13
+ fmov (\areg+),fs14
+ fmov (\areg+),fs15
+ fmov (\areg+),fs16
+ fmov (\areg+),fs17
+ fmov (\areg+),fs18
+ fmov (\areg+),fs19
+ fmov (\areg+),fs20
+ fmov (\areg+),fs21
+ fmov (\areg+),fs22
+ fmov (\areg+),fs23
+ fmov (\areg+),fs24
+ fmov (\areg+),fs25
+ fmov (\areg+),fs26
+ fmov (\areg+),fs27
+ fmov (\areg+),fs28
+ fmov (\areg+),fs29
+ fmov (\areg+),fs30
+ fmov (\areg+),fs31
+ mov (\areg),\dreg
+ fmov \dreg,fpcr
+.endm
+
+###############################################################################
+#
+# void fpu_init_state(void)
+# - initialise the FPU
+#
+###############################################################################
+ .globl fpu_init_state
+ .type fpu_init_state,@function
+fpu_init_state:
+ mov epsw,d0
+ or EPSW_FE,epsw
+
+#ifdef CONFIG_MN10300_PROC_MN103E010
+ nop
+ nop
+ nop
+#endif
+ FPU_INIT_STATE_ALL
#ifdef CONFIG_MN10300_PROC_MN103E010
nop
nop
@@ -89,40 +171,7 @@
nop
#endif
mov d0,a0
- fmov fs0,(a0+)
- fmov fs1,(a0+)
- fmov fs2,(a0+)
- fmov fs3,(a0+)
- fmov fs4,(a0+)
- fmov fs5,(a0+)
- fmov fs6,(a0+)
- fmov fs7,(a0+)
- fmov fs8,(a0+)
- fmov fs9,(a0+)
- fmov fs10,(a0+)
- fmov fs11,(a0+)
- fmov fs12,(a0+)
- fmov fs13,(a0+)
- fmov fs14,(a0+)
- fmov fs15,(a0+)
- fmov fs16,(a0+)
- fmov fs17,(a0+)
- fmov fs18,(a0+)
- fmov fs19,(a0+)
- fmov fs20,(a0+)
- fmov fs21,(a0+)
- fmov fs22,(a0+)
- fmov fs23,(a0+)
- fmov fs24,(a0+)
- fmov fs25,(a0+)
- fmov fs26,(a0+)
- fmov fs27,(a0+)
- fmov fs28,(a0+)
- fmov fs29,(a0+)
- fmov fs30,(a0+)
- fmov fs31,(a0+)
- fmov fpcr,d0
- mov d0,(a0)
+ FPU_SAVE_ALL a0,d0
#ifdef CONFIG_MN10300_PROC_MN103E010
nop
nop
@@ -135,63 +184,75 @@
###############################################################################
#
-# void fpu_restore(struct fpu_state_struct *)
-# - restore the fpu state
-# - note that an FPU Operational exception might occur during this process
+# void fpu_disabled(void)
+# - handle an exception due to the FPU being disabled
+# when CONFIG_FPU is enabled
#
###############################################################################
- .globl fpu_restore
- .type fpu_restore,@function
-fpu_restore:
- mov epsw,d1
- or EPSW_FE,epsw /* enable the FPU so we can access it */
+ .type fpu_disabled,@function
+ .globl fpu_disabled
+fpu_disabled:
+ or EPSW_nAR|EPSW_FE,epsw
+ nop
+ nop
+ nop
-#ifdef CONFIG_MN10300_PROC_MN103E010
- nop
- nop
-#endif
- mov d0,a0
- fmov (a0+),fs0
- fmov (a0+),fs1
- fmov (a0+),fs2
- fmov (a0+),fs3
- fmov (a0+),fs4
- fmov (a0+),fs5
- fmov (a0+),fs6
- fmov (a0+),fs7
- fmov (a0+),fs8
- fmov (a0+),fs9
- fmov (a0+),fs10
- fmov (a0+),fs11
- fmov (a0+),fs12
- fmov (a0+),fs13
- fmov (a0+),fs14
- fmov (a0+),fs15
- fmov (a0+),fs16
- fmov (a0+),fs17
- fmov (a0+),fs18
- fmov (a0+),fs19
- fmov (a0+),fs20
- fmov (a0+),fs21
- fmov (a0+),fs22
- fmov (a0+),fs23
- fmov (a0+),fs24
- fmov (a0+),fs25
- fmov (a0+),fs26
- fmov (a0+),fs27
- fmov (a0+),fs28
- fmov (a0+),fs29
- fmov (a0+),fs30
- fmov (a0+),fs31
- mov (a0),d0
- fmov d0,fpcr
-#ifdef CONFIG_MN10300_PROC_MN103E010
- nop
- nop
- nop
-#endif
+ mov sp,a1
+ mov (a1),d1 /* get epsw of user context */
+ and ~(THREAD_SIZE-1),a1 /* a1: (thread_info *ti) */
+ mov (TI_task,a1),a2 /* a2: (task_struct *tsk) */
+ btst EPSW_nSL,d1
+ beq fpu_used_in_kernel
- mov d1,epsw
- ret [],0
+ or EPSW_FE,d1
+ mov d1,(sp)
+ mov (TASK_THREAD+THREAD_FPU_FLAGS,a2),d1
+#ifndef CONFIG_LAZY_SAVE_FPU
+ or __THREAD_HAS_FPU,d1
+ mov d1,(TASK_THREAD+THREAD_FPU_FLAGS,a2)
+#else /* !CONFIG_LAZY_SAVE_FPU */
+ mov (fpu_state_owner),a0
+ cmp 0,a0
+ beq fpu_regs_save_end
- .size fpu_restore,.-fpu_restore
+ mov (TASK_THREAD+THREAD_UREGS,a0),a1
+ add TASK_THREAD+THREAD_FPU_STATE,a0
+ FPU_SAVE_ALL a0,d0
+
+ mov (REG_EPSW,a1),d0
+ and ~EPSW_FE,d0
+ mov d0,(REG_EPSW,a1)
+
+fpu_regs_save_end:
+ mov a2,(fpu_state_owner)
+#endif /* !CONFIG_LAZY_SAVE_FPU */
+
+ btst __THREAD_USING_FPU,d1
+ beq fpu_regs_init
+ add TASK_THREAD+THREAD_FPU_STATE,a2
+ FPU_RESTORE_ALL a2,d0
+ rti
+
+fpu_regs_init:
+ FPU_INIT_STATE_ALL
+ add TASK_THREAD+THREAD_FPU_FLAGS,a2
+ bset __THREAD_USING_FPU,(0,a2)
+ rti
+
+fpu_used_in_kernel:
+ and ~(EPSW_nAR|EPSW_FE),epsw
+ nop
+ nop
+
+ add -4,sp
+ SAVE_ALL
+ mov -1,d0
+ mov d0,(REG_ORIG_D0,fp)
+
+ and ~EPSW_NMID,epsw
+
+ mov fp,d0
+ call fpu_disabled_in_kernel[],0
+ jmp ret_from_exception
+
+ .size fpu_disabled,.-fpu_disabled