switch_to.S
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###############################################################################
#
# switch_to.S: context switch operation
#
# Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
# Written by David Howells (dhowells@redhat.com)
#
# 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/linkage.h>
#include <asm/thread_info.h>
#include <asm/processor.h>
#include <asm/registers.h>
#include <asm/spr-regs.h>
.macro LEDS val
setlos #~\val,gr27
st gr27,@(gr30,gr0)
membar
dcf @(gr30,gr0)
.endm
.section .sdata
.balign 8
# address of frame 0 (userspace) on current kernel stack
.globl __kernel_frame0_ptr
__kernel_frame0_ptr:
.long init_thread_union + THREAD_SIZE - FRV_FRAME0_SIZE
# address of current task
.globl __kernel_current_task
__kernel_current_task:
.long init_task
.section .text
.balign 4
###############################################################################
#
# struct task_struct *__switch_to(struct thread_struct *prev_thread,
# struct thread_struct *next_thread,
# struct task_struct *prev)
#
###############################################################################
.globl __switch_to
__switch_to:
# save outgoing process's context
sethi.p %hi(__switch_back),gr13
setlo %lo(__switch_back),gr13
movsg lr,gr12
stdi gr28,@(gr8,#__THREAD_FRAME)
sti sp ,@(gr8,#__THREAD_SP)
sti fp ,@(gr8,#__THREAD_FP)
stdi gr12,@(gr8,#__THREAD_LR)
stdi gr16,@(gr8,#__THREAD_GR(16))
stdi gr18,@(gr8,#__THREAD_GR(18))
stdi gr20,@(gr8,#__THREAD_GR(20))
stdi gr22,@(gr8,#__THREAD_GR(22))
stdi gr24,@(gr8,#__THREAD_GR(24))
stdi.p gr26,@(gr8,#__THREAD_GR(26))
or gr8,gr8,gr22
ldi.p @(gr8,#__THREAD_USER),gr8
call save_user_regs
or gr22,gr22,gr8
# retrieve the new context
sethi.p %hi(__kernel_frame0_ptr),gr6
setlo %lo(__kernel_frame0_ptr),gr6
movsg psr,gr4
lddi.p @(gr9,#__THREAD_FRAME),gr10
or gr10,gr10,gr27 ; save prev for the return value
ldi @(gr11,#4),gr19 ; get new_current->thread_info
lddi @(gr9,#__THREAD_SP),gr12
ldi @(gr9,#__THREAD_LR),gr14
ldi @(gr9,#__THREAD_PC),gr18
ldi.p @(gr9,#__THREAD_FRAME0),gr7
# actually switch kernel contexts with ordinary exceptions disabled
andi gr4,#~PSR_ET,gr5
movgs gr5,psr
or.p gr10,gr0,gr28 ; set __frame
or gr11,gr0,gr29 ; set __current
or.p gr12,gr0,sp
or gr13,gr0,fp
or gr19,gr0,gr15 ; set __current_thread_info
sti gr7,@(gr6,#0) ; set __kernel_frame0_ptr
sti gr29,@(gr6,#4) ; set __kernel_current_task
movgs gr14,lr
bar
# jump to __switch_back or ret_from_fork as appropriate
# - move prev to GR8
movgs gr4,psr
jmpl.p @(gr18,gr0)
or gr27,gr27,gr8
###############################################################################
#
# restore incoming process's context
# - on entry:
# - SP, FP, LR, GR15, GR28 and GR29 will have been set up appropriately
# - GR8 will point to the outgoing task_struct
# - GR9 will point to the incoming thread_struct
#
###############################################################################
__switch_back:
lddi @(gr9,#__THREAD_GR(16)),gr16
lddi @(gr9,#__THREAD_GR(18)),gr18
lddi @(gr9,#__THREAD_GR(20)),gr20
lddi @(gr9,#__THREAD_GR(22)),gr22
lddi @(gr9,#__THREAD_GR(24)),gr24
lddi @(gr9,#__THREAD_GR(26)),gr26
# fall through into restore_user_regs()
ldi.p @(gr9,#__THREAD_USER),gr8
or gr8,gr8,gr9
###############################################################################
#
# restore extra general regs and FP/Media regs
# - void *restore_user_regs(const struct user_context *target, void *retval)
# - on entry:
# - GR8 will point to the user context to swap in
# - GR9 will contain the value to be returned in GR8 (prev task on context switch)
#
###############################################################################
.globl restore_user_regs
restore_user_regs:
movsg hsr0,gr6
ori gr6,#HSR0_GRHE|HSR0_FRLE|HSR0_FRHE,gr6
movgs gr6,hsr0
movsg hsr0,gr6
movsg psr,gr7
ori gr7,#PSR_EF|PSR_EM,gr7
movgs gr7,psr
movsg psr,gr7
srli gr7,#24,gr7
bar
lddi @(gr8,#__FPMEDIA_MSR(0)),gr4
movgs gr4,msr0
movgs gr5,msr1
lddfi @(gr8,#__FPMEDIA_ACC(0)),fr16
lddfi @(gr8,#__FPMEDIA_ACC(2)),fr18
ldbfi @(gr8,#__FPMEDIA_ACCG(0)),fr20
ldbfi @(gr8,#__FPMEDIA_ACCG(1)),fr21
ldbfi @(gr8,#__FPMEDIA_ACCG(2)),fr22
ldbfi @(gr8,#__FPMEDIA_ACCG(3)),fr23
mwtacc fr16,acc0
mwtacc fr17,acc1
mwtacc fr18,acc2
mwtacc fr19,acc3
mwtaccg fr20,accg0
mwtaccg fr21,accg1
mwtaccg fr22,accg2
mwtaccg fr23,accg3
# some CPUs have extra ACCx and ACCGx regs and maybe FSRx regs
subicc.p gr7,#0x50,gr0,icc0
subicc gr7,#0x31,gr0,icc1
beq icc0,#0,__restore_acc_fr451
beq icc1,#0,__restore_acc_fr555
__restore_acc_cont:
# some CPU's have GR32-GR63
setlos #HSR0_FRHE,gr4
andcc gr6,gr4,gr0,icc0
beq icc0,#1,__restore_skip_gr32_gr63
lddi @(gr8,#__INT_GR(32)),gr32
lddi @(gr8,#__INT_GR(34)),gr34
lddi @(gr8,#__INT_GR(36)),gr36
lddi @(gr8,#__INT_GR(38)),gr38
lddi @(gr8,#__INT_GR(40)),gr40
lddi @(gr8,#__INT_GR(42)),gr42
lddi @(gr8,#__INT_GR(44)),gr44
lddi @(gr8,#__INT_GR(46)),gr46
lddi @(gr8,#__INT_GR(48)),gr48
lddi @(gr8,#__INT_GR(50)),gr50
lddi @(gr8,#__INT_GR(52)),gr52
lddi @(gr8,#__INT_GR(54)),gr54
lddi @(gr8,#__INT_GR(56)),gr56
lddi @(gr8,#__INT_GR(58)),gr58
lddi @(gr8,#__INT_GR(60)),gr60
lddi @(gr8,#__INT_GR(62)),gr62
__restore_skip_gr32_gr63:
# all CPU's have FR0-FR31
lddfi @(gr8,#__FPMEDIA_FR( 0)),fr0
lddfi @(gr8,#__FPMEDIA_FR( 2)),fr2
lddfi @(gr8,#__FPMEDIA_FR( 4)),fr4
lddfi @(gr8,#__FPMEDIA_FR( 6)),fr6
lddfi @(gr8,#__FPMEDIA_FR( 8)),fr8
lddfi @(gr8,#__FPMEDIA_FR(10)),fr10
lddfi @(gr8,#__FPMEDIA_FR(12)),fr12
lddfi @(gr8,#__FPMEDIA_FR(14)),fr14
lddfi @(gr8,#__FPMEDIA_FR(16)),fr16
lddfi @(gr8,#__FPMEDIA_FR(18)),fr18
lddfi @(gr8,#__FPMEDIA_FR(20)),fr20
lddfi @(gr8,#__FPMEDIA_FR(22)),fr22
lddfi @(gr8,#__FPMEDIA_FR(24)),fr24
lddfi @(gr8,#__FPMEDIA_FR(26)),fr26
lddfi @(gr8,#__FPMEDIA_FR(28)),fr28
lddfi.p @(gr8,#__FPMEDIA_FR(30)),fr30
# some CPU's have FR32-FR63
setlos #HSR0_FRHE,gr4
andcc gr6,gr4,gr0,icc0
beq icc0,#1,__restore_skip_fr32_fr63
lddfi @(gr8,#__FPMEDIA_FR(32)),fr32
lddfi @(gr8,#__FPMEDIA_FR(34)),fr34
lddfi @(gr8,#__FPMEDIA_FR(36)),fr36
lddfi @(gr8,#__FPMEDIA_FR(38)),fr38
lddfi @(gr8,#__FPMEDIA_FR(40)),fr40
lddfi @(gr8,#__FPMEDIA_FR(42)),fr42
lddfi @(gr8,#__FPMEDIA_FR(44)),fr44
lddfi @(gr8,#__FPMEDIA_FR(46)),fr46
lddfi @(gr8,#__FPMEDIA_FR(48)),fr48
lddfi @(gr8,#__FPMEDIA_FR(50)),fr50
lddfi @(gr8,#__FPMEDIA_FR(52)),fr52
lddfi @(gr8,#__FPMEDIA_FR(54)),fr54
lddfi @(gr8,#__FPMEDIA_FR(56)),fr56
lddfi @(gr8,#__FPMEDIA_FR(58)),fr58
lddfi @(gr8,#__FPMEDIA_FR(60)),fr60
lddfi @(gr8,#__FPMEDIA_FR(62)),fr62
__restore_skip_fr32_fr63:
lddi @(gr8,#__FPMEDIA_FNER(0)),gr4
movsg fner0,gr4
movsg fner1,gr5
or.p gr9,gr9,gr8
bralr
# the FR451 also has ACC8-11/ACCG8-11 regs (but not 4-7...)
__restore_acc_fr451:
lddfi @(gr8,#__FPMEDIA_ACC(4)),fr16
lddfi @(gr8,#__FPMEDIA_ACC(6)),fr18
ldbfi @(gr8,#__FPMEDIA_ACCG(4)),fr20
ldbfi @(gr8,#__FPMEDIA_ACCG(5)),fr21
ldbfi @(gr8,#__FPMEDIA_ACCG(6)),fr22
ldbfi @(gr8,#__FPMEDIA_ACCG(7)),fr23
mwtacc fr16,acc8
mwtacc fr17,acc9
mwtacc fr18,acc10
mwtacc fr19,acc11
mwtaccg fr20,accg8
mwtaccg fr21,accg9
mwtaccg fr22,accg10
mwtaccg fr23,accg11
bra __restore_acc_cont
# the FR555 also has ACC4-7/ACCG4-7 regs and an FSR0 reg
__restore_acc_fr555:
lddfi @(gr8,#__FPMEDIA_ACC(4)),fr16
lddfi @(gr8,#__FPMEDIA_ACC(6)),fr18
ldbfi @(gr8,#__FPMEDIA_ACCG(4)),fr20
ldbfi @(gr8,#__FPMEDIA_ACCG(5)),fr21
ldbfi @(gr8,#__FPMEDIA_ACCG(6)),fr22
ldbfi @(gr8,#__FPMEDIA_ACCG(7)),fr23
mnop.p
mwtacc fr16,acc4
mnop.p
mwtacc fr17,acc5
mnop.p
mwtacc fr18,acc6
mnop.p
mwtacc fr19,acc7
mnop.p
mwtaccg fr20,accg4
mnop.p
mwtaccg fr21,accg5
mnop.p
mwtaccg fr22,accg6
mnop.p
mwtaccg fr23,accg7
ldi @(gr8,#__FPMEDIA_FSR(0)),gr4
movgs gr4,fsr0
bra __restore_acc_cont
###############################################################################
#
# save extra general regs and FP/Media regs
# - void save_user_regs(struct user_context *target)
#
###############################################################################
.globl save_user_regs
save_user_regs:
movsg hsr0,gr6
ori gr6,#HSR0_GRHE|HSR0_FRLE|HSR0_FRHE,gr6
movgs gr6,hsr0
movsg hsr0,gr6
movsg psr,gr7
ori gr7,#PSR_EF|PSR_EM,gr7
movgs gr7,psr
movsg psr,gr7
srli gr7,#24,gr7
bar
movsg fner0,gr4
movsg fner1,gr5
stdi.p gr4,@(gr8,#__FPMEDIA_FNER(0))
# some CPU's have GR32-GR63
setlos #HSR0_GRHE,gr4
andcc gr6,gr4,gr0,icc0
beq icc0,#1,__save_skip_gr32_gr63
stdi gr32,@(gr8,#__INT_GR(32))
stdi gr34,@(gr8,#__INT_GR(34))
stdi gr36,@(gr8,#__INT_GR(36))
stdi gr38,@(gr8,#__INT_GR(38))
stdi gr40,@(gr8,#__INT_GR(40))
stdi gr42,@(gr8,#__INT_GR(42))
stdi gr44,@(gr8,#__INT_GR(44))
stdi gr46,@(gr8,#__INT_GR(46))
stdi gr48,@(gr8,#__INT_GR(48))
stdi gr50,@(gr8,#__INT_GR(50))
stdi gr52,@(gr8,#__INT_GR(52))
stdi gr54,@(gr8,#__INT_GR(54))
stdi gr56,@(gr8,#__INT_GR(56))
stdi gr58,@(gr8,#__INT_GR(58))
stdi gr60,@(gr8,#__INT_GR(60))
stdi gr62,@(gr8,#__INT_GR(62))
__save_skip_gr32_gr63:
# all CPU's have FR0-FR31
stdfi fr0 ,@(gr8,#__FPMEDIA_FR( 0))
stdfi fr2 ,@(gr8,#__FPMEDIA_FR( 2))
stdfi fr4 ,@(gr8,#__FPMEDIA_FR( 4))
stdfi fr6 ,@(gr8,#__FPMEDIA_FR( 6))
stdfi fr8 ,@(gr8,#__FPMEDIA_FR( 8))
stdfi fr10,@(gr8,#__FPMEDIA_FR(10))
stdfi fr12,@(gr8,#__FPMEDIA_FR(12))
stdfi fr14,@(gr8,#__FPMEDIA_FR(14))
stdfi fr16,@(gr8,#__FPMEDIA_FR(16))
stdfi fr18,@(gr8,#__FPMEDIA_FR(18))
stdfi fr20,@(gr8,#__FPMEDIA_FR(20))
stdfi fr22,@(gr8,#__FPMEDIA_FR(22))
stdfi fr24,@(gr8,#__FPMEDIA_FR(24))
stdfi fr26,@(gr8,#__FPMEDIA_FR(26))
stdfi fr28,@(gr8,#__FPMEDIA_FR(28))
stdfi.p fr30,@(gr8,#__FPMEDIA_FR(30))
# some CPU's have FR32-FR63
setlos #HSR0_FRHE,gr4
andcc gr6,gr4,gr0,icc0
beq icc0,#1,__save_skip_fr32_fr63
stdfi fr32,@(gr8,#__FPMEDIA_FR(32))
stdfi fr34,@(gr8,#__FPMEDIA_FR(34))
stdfi fr36,@(gr8,#__FPMEDIA_FR(36))
stdfi fr38,@(gr8,#__FPMEDIA_FR(38))
stdfi fr40,@(gr8,#__FPMEDIA_FR(40))
stdfi fr42,@(gr8,#__FPMEDIA_FR(42))
stdfi fr44,@(gr8,#__FPMEDIA_FR(44))
stdfi fr46,@(gr8,#__FPMEDIA_FR(46))
stdfi fr48,@(gr8,#__FPMEDIA_FR(48))
stdfi fr50,@(gr8,#__FPMEDIA_FR(50))
stdfi fr52,@(gr8,#__FPMEDIA_FR(52))
stdfi fr54,@(gr8,#__FPMEDIA_FR(54))
stdfi fr56,@(gr8,#__FPMEDIA_FR(56))
stdfi fr58,@(gr8,#__FPMEDIA_FR(58))
stdfi fr60,@(gr8,#__FPMEDIA_FR(60))
stdfi fr62,@(gr8,#__FPMEDIA_FR(62))
__save_skip_fr32_fr63:
mrdacc acc0 ,fr4
mrdacc acc1 ,fr5
stdfi.p fr4 ,@(gr8,#__FPMEDIA_ACC(0))
mrdacc acc2 ,fr6
mrdacc acc3 ,fr7
stdfi.p fr6 ,@(gr8,#__FPMEDIA_ACC(2))
mrdaccg accg0,fr4
stbfi.p fr4 ,@(gr8,#__FPMEDIA_ACCG(0))
mrdaccg accg1,fr5
stbfi.p fr5 ,@(gr8,#__FPMEDIA_ACCG(1))
mrdaccg accg2,fr6
stbfi.p fr6 ,@(gr8,#__FPMEDIA_ACCG(2))
mrdaccg accg3,fr7
stbfi fr7 ,@(gr8,#__FPMEDIA_ACCG(3))
movsg msr0 ,gr4
movsg msr1 ,gr5
stdi gr4 ,@(gr8,#__FPMEDIA_MSR(0))
# some CPUs have extra ACCx and ACCGx regs and maybe FSRx regs
subicc.p gr7,#0x50,gr0,icc0
subicc gr7,#0x31,gr0,icc1
beq icc0,#0,__save_acc_fr451
beq icc1,#0,__save_acc_fr555
__save_acc_cont:
lddfi @(gr8,#__FPMEDIA_FR(4)),fr4
lddfi.p @(gr8,#__FPMEDIA_FR(6)),fr6
bralr
# the FR451 also has ACC8-11/ACCG8-11 regs (but not 4-7...)
__save_acc_fr451:
mrdacc acc8 ,fr4
mrdacc acc9 ,fr5
stdfi.p fr4 ,@(gr8,#__FPMEDIA_ACC(4))
mrdacc acc10,fr6
mrdacc acc11,fr7
stdfi.p fr6 ,@(gr8,#__FPMEDIA_ACC(6))
mrdaccg accg8,fr4
stbfi.p fr4 ,@(gr8,#__FPMEDIA_ACCG(4))
mrdaccg accg9,fr5
stbfi.p fr5 ,@(gr8,#__FPMEDIA_ACCG(5))
mrdaccg accg10,fr6
stbfi.p fr6 ,@(gr8,#__FPMEDIA_ACCG(6))
mrdaccg accg11,fr7
stbfi fr7 ,@(gr8,#__FPMEDIA_ACCG(7))
bra __save_acc_cont
# the FR555 also has ACC4-7/ACCG4-7 regs and an FSR0 reg
__save_acc_fr555:
mnop.p
mrdacc acc4 ,fr4
mnop.p
mrdacc acc5 ,fr5
stdfi fr4 ,@(gr8,#__FPMEDIA_ACC(4))
mnop.p
mrdacc acc6 ,fr6
mnop.p
mrdacc acc7 ,fr7
stdfi fr6 ,@(gr8,#__FPMEDIA_ACC(6))
mnop.p
mrdaccg accg4,fr4
stbfi fr4 ,@(gr8,#__FPMEDIA_ACCG(4))
mnop.p
mrdaccg accg5,fr5
stbfi fr5 ,@(gr8,#__FPMEDIA_ACCG(5))
mnop.p
mrdaccg accg6,fr6
stbfi fr6 ,@(gr8,#__FPMEDIA_ACCG(6))
mnop.p
mrdaccg accg7,fr7
stbfi fr7 ,@(gr8,#__FPMEDIA_ACCG(7))
movsg fsr0 ,gr4
sti gr4 ,@(gr8,#__FPMEDIA_FSR(0))
bra __save_acc_cont