--- /dev/null
+###############################################################################
+#
+# 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/config.h>
+#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 - USER_CONTEXT_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
+
+ srli gr15,#28,gr5
+ subicc gr5,#0xc,gr0,icc0
+ beq icc0,#0,111f
+ break
+ nop
+111:
+
+ # 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
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