1119 lines
30 KiB
ArmAsm
1119 lines
30 KiB
ArmAsm
/*
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* OpenRISC entry.S
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* Modifications for the OpenRISC architecture:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/linkage.h>
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#include <asm/processor.h>
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#include <asm/unistd.h>
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#include <asm/thread_info.h>
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#include <asm/errno.h>
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#include <asm/spr_defs.h>
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#include <asm/page.h>
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#include <asm/mmu.h>
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#include <asm/pgtable.h>
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#include <asm/asm-offsets.h>
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#define DISABLE_INTERRUPTS(t1,t2) \
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l.mfspr t2,r0,SPR_SR ;\
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l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
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l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
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l.and t2,t2,t1 ;\
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l.mtspr r0,t2,SPR_SR
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#define ENABLE_INTERRUPTS(t1) \
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l.mfspr t1,r0,SPR_SR ;\
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l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\
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l.mtspr r0,t1,SPR_SR
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/* =========================================================[ macros ]=== */
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/*
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* We need to disable interrupts at beginning of RESTORE_ALL
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* since interrupt might come in after we've loaded EPC return address
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* and overwrite EPC with address somewhere in RESTORE_ALL
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* which is of course wrong!
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*/
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#define RESTORE_ALL \
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DISABLE_INTERRUPTS(r3,r4) ;\
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l.lwz r3,PT_PC(r1) ;\
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l.mtspr r0,r3,SPR_EPCR_BASE ;\
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l.lwz r3,PT_SR(r1) ;\
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l.mtspr r0,r3,SPR_ESR_BASE ;\
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l.lwz r2,PT_GPR2(r1) ;\
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l.lwz r3,PT_GPR3(r1) ;\
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l.lwz r4,PT_GPR4(r1) ;\
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l.lwz r5,PT_GPR5(r1) ;\
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l.lwz r6,PT_GPR6(r1) ;\
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l.lwz r7,PT_GPR7(r1) ;\
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l.lwz r8,PT_GPR8(r1) ;\
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l.lwz r9,PT_GPR9(r1) ;\
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l.lwz r10,PT_GPR10(r1) ;\
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l.lwz r11,PT_GPR11(r1) ;\
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l.lwz r12,PT_GPR12(r1) ;\
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l.lwz r13,PT_GPR13(r1) ;\
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l.lwz r14,PT_GPR14(r1) ;\
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l.lwz r15,PT_GPR15(r1) ;\
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l.lwz r16,PT_GPR16(r1) ;\
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l.lwz r17,PT_GPR17(r1) ;\
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l.lwz r18,PT_GPR18(r1) ;\
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l.lwz r19,PT_GPR19(r1) ;\
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l.lwz r20,PT_GPR20(r1) ;\
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l.lwz r21,PT_GPR21(r1) ;\
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l.lwz r22,PT_GPR22(r1) ;\
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l.lwz r23,PT_GPR23(r1) ;\
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l.lwz r24,PT_GPR24(r1) ;\
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l.lwz r25,PT_GPR25(r1) ;\
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l.lwz r26,PT_GPR26(r1) ;\
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l.lwz r27,PT_GPR27(r1) ;\
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l.lwz r28,PT_GPR28(r1) ;\
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l.lwz r29,PT_GPR29(r1) ;\
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l.lwz r30,PT_GPR30(r1) ;\
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l.lwz r31,PT_GPR31(r1) ;\
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l.lwz r1,PT_SP(r1) ;\
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l.rfe
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#define EXCEPTION_ENTRY(handler) \
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.global handler ;\
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handler: ;\
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/* r1, EPCR, ESR a already saved */ ;\
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l.sw PT_GPR2(r1),r2 ;\
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l.sw PT_GPR3(r1),r3 ;\
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/* r4 already save */ ;\
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l.sw PT_GPR5(r1),r5 ;\
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l.sw PT_GPR6(r1),r6 ;\
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l.sw PT_GPR7(r1),r7 ;\
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l.sw PT_GPR8(r1),r8 ;\
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l.sw PT_GPR9(r1),r9 ;\
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/* r10 already saved */ ;\
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l.sw PT_GPR11(r1),r11 ;\
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/* r12 already saved */ ;\
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l.sw PT_GPR13(r1),r13 ;\
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l.sw PT_GPR14(r1),r14 ;\
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l.sw PT_GPR15(r1),r15 ;\
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l.sw PT_GPR16(r1),r16 ;\
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l.sw PT_GPR17(r1),r17 ;\
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l.sw PT_GPR18(r1),r18 ;\
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l.sw PT_GPR19(r1),r19 ;\
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l.sw PT_GPR20(r1),r20 ;\
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l.sw PT_GPR21(r1),r21 ;\
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l.sw PT_GPR22(r1),r22 ;\
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l.sw PT_GPR23(r1),r23 ;\
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l.sw PT_GPR24(r1),r24 ;\
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l.sw PT_GPR25(r1),r25 ;\
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l.sw PT_GPR26(r1),r26 ;\
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l.sw PT_GPR27(r1),r27 ;\
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l.sw PT_GPR28(r1),r28 ;\
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l.sw PT_GPR29(r1),r29 ;\
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/* r30 already save */ ;\
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/* l.sw PT_GPR30(r1),r30*/ ;\
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l.sw PT_GPR31(r1),r31 ;\
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/* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
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l.addi r30,r0,-1 ;\
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l.sw PT_ORIG_GPR11(r1),r30
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#define UNHANDLED_EXCEPTION(handler,vector) \
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.global handler ;\
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handler: ;\
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/* r1, EPCR, ESR already saved */ ;\
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l.sw PT_GPR2(r1),r2 ;\
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l.sw PT_GPR3(r1),r3 ;\
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l.sw PT_GPR5(r1),r5 ;\
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l.sw PT_GPR6(r1),r6 ;\
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l.sw PT_GPR7(r1),r7 ;\
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l.sw PT_GPR8(r1),r8 ;\
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l.sw PT_GPR9(r1),r9 ;\
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/* r10 already saved */ ;\
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l.sw PT_GPR11(r1),r11 ;\
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/* r12 already saved */ ;\
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l.sw PT_GPR13(r1),r13 ;\
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l.sw PT_GPR14(r1),r14 ;\
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l.sw PT_GPR15(r1),r15 ;\
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l.sw PT_GPR16(r1),r16 ;\
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l.sw PT_GPR17(r1),r17 ;\
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l.sw PT_GPR18(r1),r18 ;\
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l.sw PT_GPR19(r1),r19 ;\
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l.sw PT_GPR20(r1),r20 ;\
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l.sw PT_GPR21(r1),r21 ;\
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l.sw PT_GPR22(r1),r22 ;\
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l.sw PT_GPR23(r1),r23 ;\
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l.sw PT_GPR24(r1),r24 ;\
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l.sw PT_GPR25(r1),r25 ;\
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l.sw PT_GPR26(r1),r26 ;\
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l.sw PT_GPR27(r1),r27 ;\
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l.sw PT_GPR28(r1),r28 ;\
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l.sw PT_GPR29(r1),r29 ;\
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/* r31 already saved */ ;\
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l.sw PT_GPR30(r1),r30 ;\
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/* l.sw PT_GPR31(r1),r31 */ ;\
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/* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
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l.addi r30,r0,-1 ;\
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l.sw PT_ORIG_GPR11(r1),r30 ;\
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l.addi r3,r1,0 ;\
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/* r4 is exception EA */ ;\
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l.addi r5,r0,vector ;\
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l.jal unhandled_exception ;\
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l.nop ;\
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l.j _ret_from_exception ;\
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l.nop
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/*
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* NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR
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* contain the same values as when exception we're handling
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* occured. in fact they never do. if you need them use
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* values saved on stack (for SPR_EPC, SPR_ESR) or content
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* of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE()
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* in 'arch/or32/kernel/head.S'
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*/
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/* =====================================================[ exceptions] === */
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/* ---[ 0x100: RESET exception ]----------------------------------------- */
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EXCEPTION_ENTRY(_tng_kernel_start)
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l.jal _start
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l.andi r0,r0,0
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/* ---[ 0x200: BUS exception ]------------------------------------------- */
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EXCEPTION_ENTRY(_bus_fault_handler)
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/* r4: EA of fault (set by EXCEPTION_HANDLE) */
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l.jal do_bus_fault
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l.addi r3,r1,0 /* pt_regs */
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l.j _ret_from_exception
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l.nop
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/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
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EXCEPTION_ENTRY(_data_page_fault_handler)
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/* set up parameters for do_page_fault */
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l.addi r3,r1,0 // pt_regs
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/* r4 set be EXCEPTION_HANDLE */ // effective address of fault
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l.ori r5,r0,0x300 // exception vector
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/*
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* __PHX__: TODO
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*
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* all this can be written much simpler. look at
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* DTLB miss handler in the CONFIG_GUARD_PROTECTED_CORE part
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*/
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#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
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l.lwz r6,PT_PC(r3) // address of an offending insn
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l.lwz r6,0(r6) // instruction that caused pf
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l.srli r6,r6,26 // check opcode for jump insn
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l.sfeqi r6,0 // l.j
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l.bf 8f
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l.sfeqi r6,1 // l.jal
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l.bf 8f
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l.sfeqi r6,3 // l.bnf
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l.bf 8f
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l.sfeqi r6,4 // l.bf
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l.bf 8f
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l.sfeqi r6,0x11 // l.jr
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l.bf 8f
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l.sfeqi r6,0x12 // l.jalr
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l.bf 8f
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l.nop
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l.j 9f
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l.nop
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8:
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l.lwz r6,PT_PC(r3) // address of an offending insn
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l.addi r6,r6,4
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l.lwz r6,0(r6) // instruction that caused pf
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l.srli r6,r6,26 // get opcode
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9:
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#else
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l.mfspr r6,r0,SPR_SR // SR
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// l.lwz r6,PT_SR(r3) // ESR
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l.andi r6,r6,SPR_SR_DSX // check for delay slot exception
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l.sfeqi r6,0x1 // exception happened in delay slot
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l.bnf 7f
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l.lwz r6,PT_PC(r3) // address of an offending insn
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l.addi r6,r6,4 // offending insn is in delay slot
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7:
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l.lwz r6,0(r6) // instruction that caused pf
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l.srli r6,r6,26 // check opcode for write access
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#endif
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l.sfgeui r6,0x34 // check opcode for write access
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l.bnf 1f
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l.sfleui r6,0x37
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l.bnf 1f
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l.ori r6,r0,0x1 // write access
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l.j 2f
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l.nop
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1: l.ori r6,r0,0x0 // !write access
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2:
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/* call fault.c handler in or32/mm/fault.c */
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l.jal do_page_fault
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l.nop
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l.j _ret_from_exception
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l.nop
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/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
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EXCEPTION_ENTRY(_insn_page_fault_handler)
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/* set up parameters for do_page_fault */
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l.addi r3,r1,0 // pt_regs
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/* r4 set be EXCEPTION_HANDLE */ // effective address of fault
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l.ori r5,r0,0x400 // exception vector
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l.ori r6,r0,0x0 // !write access
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/* call fault.c handler in or32/mm/fault.c */
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l.jal do_page_fault
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l.nop
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l.j _ret_from_exception
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l.nop
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/* ---[ 0x500: Timer exception ]----------------------------------------- */
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EXCEPTION_ENTRY(_timer_handler)
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l.jal timer_interrupt
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l.addi r3,r1,0 /* pt_regs */
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l.j _ret_from_intr
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l.nop
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/* ---[ 0x600: Aligment exception ]-------------------------------------- */
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EXCEPTION_ENTRY(_alignment_handler)
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/* r4: EA of fault (set by EXCEPTION_HANDLE) */
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l.jal do_unaligned_access
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l.addi r3,r1,0 /* pt_regs */
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l.j _ret_from_exception
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l.nop
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#if 0
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EXCEPTION_ENTRY(_aligment_handler)
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// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the efective addres */
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l.addi r2,r4,0
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// l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */
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l.lwz r5,PT_PC(r1)
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l.lwz r3,0(r5) /* Load insn */
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l.srli r4,r3,26 /* Shift left to get the insn opcode */
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l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */
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l.bf jmp
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l.sfeqi r4,0x01
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l.bf jmp
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l.sfeqi r4,0x03
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l.bf jmp
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l.sfeqi r4,0x04
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l.bf jmp
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l.sfeqi r4,0x11
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l.bf jr
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l.sfeqi r4,0x12
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l.bf jr
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l.nop
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l.j 1f
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l.addi r5,r5,4 /* Increment PC to get return insn address */
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jmp:
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l.slli r4,r3,6 /* Get the signed extended jump length */
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l.srai r4,r4,4
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l.lwz r3,4(r5) /* Load the real load/store insn */
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l.add r5,r5,r4 /* Calculate jump target address */
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l.j 1f
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l.srli r4,r3,26 /* Shift left to get the insn opcode */
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jr:
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l.slli r4,r3,9 /* Shift to get the reg nb */
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l.andi r4,r4,0x7c
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l.lwz r3,4(r5) /* Load the real load/store insn */
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l.add r4,r4,r1 /* Load the jump register value from the stack */
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l.lwz r5,0(r4)
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l.srli r4,r3,26 /* Shift left to get the insn opcode */
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1:
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// l.mtspr r0,r5,SPR_EPCR_BASE
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l.sw PT_PC(r1),r5
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l.sfeqi r4,0x26
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l.bf lhs
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l.sfeqi r4,0x25
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l.bf lhz
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l.sfeqi r4,0x22
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l.bf lws
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l.sfeqi r4,0x21
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l.bf lwz
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l.sfeqi r4,0x37
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l.bf sh
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l.sfeqi r4,0x35
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l.bf sw
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l.nop
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1: l.j 1b /* I don't know what to do */
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l.nop
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lhs: l.lbs r5,0(r2)
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l.slli r5,r5,8
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l.lbz r6,1(r2)
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l.or r5,r5,r6
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l.srli r4,r3,19
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l.andi r4,r4,0x7c
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l.add r4,r4,r1
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l.j align_end
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l.sw 0(r4),r5
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lhz: l.lbz r5,0(r2)
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l.slli r5,r5,8
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l.lbz r6,1(r2)
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l.or r5,r5,r6
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l.srli r4,r3,19
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l.andi r4,r4,0x7c
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l.add r4,r4,r1
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l.j align_end
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l.sw 0(r4),r5
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lws: l.lbs r5,0(r2)
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l.slli r5,r5,24
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l.lbz r6,1(r2)
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l.slli r6,r6,16
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l.or r5,r5,r6
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l.lbz r6,2(r2)
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l.slli r6,r6,8
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l.or r5,r5,r6
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l.lbz r6,3(r2)
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l.or r5,r5,r6
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l.srli r4,r3,19
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l.andi r4,r4,0x7c
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l.add r4,r4,r1
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l.j align_end
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l.sw 0(r4),r5
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lwz: l.lbz r5,0(r2)
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l.slli r5,r5,24
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l.lbz r6,1(r2)
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l.slli r6,r6,16
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l.or r5,r5,r6
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l.lbz r6,2(r2)
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l.slli r6,r6,8
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l.or r5,r5,r6
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l.lbz r6,3(r2)
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l.or r5,r5,r6
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l.srli r4,r3,19
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l.andi r4,r4,0x7c
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l.add r4,r4,r1
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l.j align_end
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l.sw 0(r4),r5
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sh:
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l.srli r4,r3,9
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l.andi r4,r4,0x7c
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l.add r4,r4,r1
|
|
l.lwz r5,0(r4)
|
|
l.sb 1(r2),r5
|
|
l.srli r5,r5,8
|
|
l.j align_end
|
|
l.sb 0(r2),r5
|
|
|
|
sw:
|
|
l.srli r4,r3,9
|
|
l.andi r4,r4,0x7c
|
|
l.add r4,r4,r1
|
|
l.lwz r5,0(r4)
|
|
l.sb 3(r2),r5
|
|
l.srli r5,r5,8
|
|
l.sb 2(r2),r5
|
|
l.srli r5,r5,8
|
|
l.sb 1(r2),r5
|
|
l.srli r5,r5,8
|
|
l.j align_end
|
|
l.sb 0(r2),r5
|
|
|
|
align_end:
|
|
l.j _ret_from_intr
|
|
l.nop
|
|
#endif
|
|
|
|
/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
|
|
|
|
EXCEPTION_ENTRY(_illegal_instruction_handler)
|
|
/* r4: EA of fault (set by EXCEPTION_HANDLE) */
|
|
l.jal do_illegal_instruction
|
|
l.addi r3,r1,0 /* pt_regs */
|
|
|
|
l.j _ret_from_exception
|
|
l.nop
|
|
|
|
/* ---[ 0x800: External interrupt exception ]---------------------------- */
|
|
|
|
EXCEPTION_ENTRY(_external_irq_handler)
|
|
#ifdef CONFIG_OPENRISC_ESR_EXCEPTION_BUG_CHECK
|
|
l.lwz r4,PT_SR(r1) // were interrupts enabled ?
|
|
l.andi r4,r4,SPR_SR_IEE
|
|
l.sfeqi r4,0
|
|
l.bnf 1f // ext irq enabled, all ok.
|
|
l.nop
|
|
|
|
l.addi r1,r1,-0x8
|
|
l.movhi r3,hi(42f)
|
|
l.ori r3,r3,lo(42f)
|
|
l.sw 0x0(r1),r3
|
|
l.jal printk
|
|
l.sw 0x4(r1),r4
|
|
l.addi r1,r1,0x8
|
|
|
|
.section .rodata, "a"
|
|
42:
|
|
.string "\n\rESR interrupt bug: in _external_irq_handler (ESR %x)\n\r"
|
|
.align 4
|
|
.previous
|
|
|
|
l.ori r4,r4,SPR_SR_IEE // fix the bug
|
|
// l.sw PT_SR(r1),r4
|
|
1:
|
|
#endif
|
|
l.addi r3,r1,0
|
|
l.movhi r8,hi(do_IRQ)
|
|
l.ori r8,r8,lo(do_IRQ)
|
|
l.jalr r8
|
|
l.nop
|
|
l.j _ret_from_intr
|
|
l.nop
|
|
|
|
/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
|
|
|
|
|
|
/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
|
|
|
|
|
|
/* ---[ 0xb00: Range exception ]----------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0xb00,0xb00)
|
|
|
|
/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
|
|
|
|
/*
|
|
* Syscalls are a special type of exception in that they are
|
|
* _explicitly_ invoked by userspace and can therefore be
|
|
* held to conform to the same ABI as normal functions with
|
|
* respect to whether registers are preserved across the call
|
|
* or not.
|
|
*/
|
|
|
|
/* Upon syscall entry we just save the callee-saved registers
|
|
* and not the call-clobbered ones.
|
|
*/
|
|
|
|
_string_syscall_return:
|
|
.string "syscall return %ld \n\r\0"
|
|
.align 4
|
|
|
|
ENTRY(_sys_call_handler)
|
|
/* syscalls run with interrupts enabled */
|
|
ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
|
|
|
|
/* r1, EPCR, ESR a already saved */
|
|
l.sw PT_GPR2(r1),r2
|
|
/* r3-r8 must be saved because syscall restart relies
|
|
* on us being able to restart the syscall args... technically
|
|
* they should be clobbered, otherwise
|
|
*/
|
|
l.sw PT_GPR3(r1),r3
|
|
/* r4 already saved */
|
|
/* r4 holds the EEAR address of the fault, load the original r4 */
|
|
l.lwz r4,PT_GPR4(r1)
|
|
l.sw PT_GPR5(r1),r5
|
|
l.sw PT_GPR6(r1),r6
|
|
l.sw PT_GPR7(r1),r7
|
|
l.sw PT_GPR8(r1),r8
|
|
l.sw PT_GPR9(r1),r9
|
|
/* r10 already saved */
|
|
l.sw PT_GPR11(r1),r11
|
|
/* orig_gpr11 must be set for syscalls */
|
|
l.sw PT_ORIG_GPR11(r1),r11
|
|
/* r12,r13 already saved */
|
|
|
|
/* r14-r28 (even) aren't touched by the syscall fast path below
|
|
* so we don't need to save them. However, the functions that return
|
|
* to userspace via a call to switch() DO need to save these because
|
|
* switch() effectively clobbers them... saving these registers for
|
|
* such functions is handled in their syscall wrappers (see fork, vfork,
|
|
* and clone, below).
|
|
|
|
/* r30 is the only register we clobber in the fast path */
|
|
/* r30 already saved */
|
|
/* l.sw PT_GPR30(r1),r30 */
|
|
|
|
_syscall_check_trace_enter:
|
|
/* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */
|
|
l.lwz r30,TI_FLAGS(r10)
|
|
l.andi r30,r30,_TIF_SYSCALL_TRACE
|
|
l.sfne r30,r0
|
|
l.bf _syscall_trace_enter
|
|
l.nop
|
|
|
|
_syscall_check:
|
|
/* Ensure that the syscall number is reasonable */
|
|
l.sfgeui r11,__NR_syscalls
|
|
l.bf _syscall_badsys
|
|
l.nop
|
|
|
|
_syscall_call:
|
|
l.movhi r29,hi(sys_call_table)
|
|
l.ori r29,r29,lo(sys_call_table)
|
|
l.slli r11,r11,2
|
|
l.add r29,r29,r11
|
|
l.lwz r29,0(r29)
|
|
|
|
l.jalr r29
|
|
l.nop
|
|
|
|
_syscall_return:
|
|
/* All syscalls return here... just pay attention to ret_from_fork
|
|
* which does it in a round-about way.
|
|
*/
|
|
l.sw PT_GPR11(r1),r11 // save return value
|
|
|
|
#if 0
|
|
_syscall_debug:
|
|
l.movhi r3,hi(_string_syscall_return)
|
|
l.ori r3,r3,lo(_string_syscall_return)
|
|
l.ori r27,r0,1
|
|
l.sw -4(r1),r27
|
|
l.sw -8(r1),r11
|
|
l.addi r1,r1,-8
|
|
l.movhi r27,hi(printk)
|
|
l.ori r27,r27,lo(printk)
|
|
l.jalr r27
|
|
l.nop
|
|
l.addi r1,r1,8
|
|
#endif
|
|
|
|
_syscall_check_trace_leave:
|
|
/* r30 is a callee-saved register so this should still hold the
|
|
* _TIF_SYSCALL_TRACE flag from _syscall_check_trace_enter above...
|
|
* _syscall_trace_leave expects syscall result to be in pt_regs->r11.
|
|
*/
|
|
l.sfne r30,r0
|
|
l.bf _syscall_trace_leave
|
|
l.nop
|
|
|
|
/* This is where the exception-return code begins... interrupts need to be
|
|
* disabled the rest of the way here because we can't afford to miss any
|
|
* interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */
|
|
|
|
_syscall_check_work:
|
|
/* Here we need to disable interrupts */
|
|
DISABLE_INTERRUPTS(r27,r29)
|
|
l.lwz r30,TI_FLAGS(r10)
|
|
l.andi r30,r30,_TIF_WORK_MASK
|
|
l.sfne r30,r0
|
|
|
|
l.bnf _syscall_resume_userspace
|
|
l.nop
|
|
|
|
/* Work pending follows a different return path, so we need to
|
|
* make sure that all the call-saved registers get into pt_regs
|
|
* before branching...
|
|
*/
|
|
l.sw PT_GPR14(r1),r14
|
|
l.sw PT_GPR16(r1),r16
|
|
l.sw PT_GPR18(r1),r18
|
|
l.sw PT_GPR20(r1),r20
|
|
l.sw PT_GPR22(r1),r22
|
|
l.sw PT_GPR24(r1),r24
|
|
l.sw PT_GPR26(r1),r26
|
|
l.sw PT_GPR28(r1),r28
|
|
|
|
/* _work_pending needs to be called with interrupts disabled */
|
|
l.j _work_pending
|
|
l.nop
|
|
|
|
_syscall_resume_userspace:
|
|
// ENABLE_INTERRUPTS(r29)
|
|
|
|
|
|
/* This is the hot path for returning to userspace from a syscall. If there's
|
|
* work to be done and the branch to _work_pending was taken above, then the
|
|
* return to userspace will be done via the normal exception return path...
|
|
* that path restores _all_ registers and will overwrite the "clobbered"
|
|
* registers with whatever garbage is in pt_regs -- that's OK because those
|
|
* registers are clobbered anyway and because the extra work is insignificant
|
|
* in the context of the extra work that _work_pending is doing.
|
|
|
|
/* Once again, syscalls are special and only guarantee to preserve the
|
|
* same registers as a normal function call */
|
|
|
|
/* The assumption here is that the registers r14-r28 (even) are untouched and
|
|
* don't need to be restored... be sure that that's really the case!
|
|
*/
|
|
|
|
/* This is still too much... we should only be restoring what we actually
|
|
* clobbered... we should even be using 'scratch' (odd) regs above so that
|
|
* we don't need to restore anything, hardly...
|
|
*/
|
|
|
|
l.lwz r2,PT_GPR2(r1)
|
|
|
|
/* Restore args */
|
|
/* r3-r8 are technically clobbered, but syscall restart needs these
|
|
* to be restored...
|
|
*/
|
|
l.lwz r3,PT_GPR3(r1)
|
|
l.lwz r4,PT_GPR4(r1)
|
|
l.lwz r5,PT_GPR5(r1)
|
|
l.lwz r6,PT_GPR6(r1)
|
|
l.lwz r7,PT_GPR7(r1)
|
|
l.lwz r8,PT_GPR8(r1)
|
|
|
|
l.lwz r9,PT_GPR9(r1)
|
|
l.lwz r10,PT_GPR10(r1)
|
|
l.lwz r11,PT_GPR11(r1)
|
|
|
|
/* r30 is the only register we clobber in the fast path */
|
|
l.lwz r30,PT_GPR30(r1)
|
|
|
|
/* Here we use r13-r19 (odd) as scratch regs */
|
|
l.lwz r13,PT_PC(r1)
|
|
l.lwz r15,PT_SR(r1)
|
|
l.lwz r1,PT_SP(r1)
|
|
/* Interrupts need to be disabled for setting EPCR and ESR
|
|
* so that another interrupt doesn't come in here and clobber
|
|
* them before we can use them for our l.rfe */
|
|
DISABLE_INTERRUPTS(r17,r19)
|
|
l.mtspr r0,r13,SPR_EPCR_BASE
|
|
l.mtspr r0,r15,SPR_ESR_BASE
|
|
l.rfe
|
|
|
|
/* End of hot path!
|
|
* Keep the below tracing and error handling out of the hot path...
|
|
*/
|
|
|
|
_syscall_trace_enter:
|
|
/* Here we pass pt_regs to do_syscall_trace_enter. Make sure
|
|
* that function is really getting all the info it needs as
|
|
* pt_regs isn't a complete set of userspace regs, just the
|
|
* ones relevant to the syscall...
|
|
*
|
|
* Note use of delay slot for setting argument.
|
|
*/
|
|
l.jal do_syscall_trace_enter
|
|
l.addi r3,r1,0
|
|
|
|
/* Restore arguments (not preserved across do_syscall_trace_enter)
|
|
* so that we can do the syscall for real and return to the syscall
|
|
* hot path.
|
|
*/
|
|
l.lwz r11,PT_GPR11(r1)
|
|
l.lwz r3,PT_GPR3(r1)
|
|
l.lwz r4,PT_GPR4(r1)
|
|
l.lwz r5,PT_GPR5(r1)
|
|
l.lwz r6,PT_GPR6(r1)
|
|
l.lwz r7,PT_GPR7(r1)
|
|
|
|
l.j _syscall_check
|
|
l.lwz r8,PT_GPR8(r1)
|
|
|
|
_syscall_trace_leave:
|
|
l.jal do_syscall_trace_leave
|
|
l.addi r3,r1,0
|
|
|
|
l.j _syscall_check_work
|
|
l.nop
|
|
|
|
_syscall_badsys:
|
|
/* Here we effectively pretend to have executed an imaginary
|
|
* syscall that returns -ENOSYS and then return to the regular
|
|
* syscall hot path.
|
|
* Note that "return value" is set in the delay slot...
|
|
*/
|
|
l.j _syscall_return
|
|
l.addi r11,r0,-ENOSYS
|
|
|
|
/******* END SYSCALL HANDLING *******/
|
|
|
|
/* ---[ 0xd00: Trap exception ]------------------------------------------ */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0xd00,0xd00)
|
|
|
|
/* ---[ 0xe00: Trap exception ]------------------------------------------ */
|
|
|
|
EXCEPTION_ENTRY(_trap_handler)
|
|
/* r4: EA of fault (set by EXCEPTION_HANDLE) */
|
|
l.jal do_trap
|
|
l.addi r3,r1,0 /* pt_regs */
|
|
|
|
l.j _ret_from_exception
|
|
l.nop
|
|
|
|
/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0xf00,0xf00)
|
|
|
|
/* ---[ 0x1000: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1000,0x1000)
|
|
|
|
/* ---[ 0x1100: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1100,0x1100)
|
|
|
|
/* ---[ 0x1200: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1200,0x1200)
|
|
|
|
/* ---[ 0x1300: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1300,0x1300)
|
|
|
|
/* ---[ 0x1400: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1400,0x1400)
|
|
|
|
/* ---[ 0x1500: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1500,0x1500)
|
|
|
|
/* ---[ 0x1600: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1600,0x1600)
|
|
|
|
/* ---[ 0x1700: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1700,0x1700)
|
|
|
|
/* ---[ 0x1800: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1800,0x1800)
|
|
|
|
/* ---[ 0x1900: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1900,0x1900)
|
|
|
|
/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00)
|
|
|
|
/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00)
|
|
|
|
/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00)
|
|
|
|
/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00)
|
|
|
|
/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00)
|
|
|
|
/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
|
|
|
|
UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00)
|
|
|
|
/* ========================================================[ return ] === */
|
|
|
|
_work_pending:
|
|
/*
|
|
* if (current_thread_info->flags & _TIF_NEED_RESCHED)
|
|
* schedule();
|
|
*/
|
|
l.lwz r5,TI_FLAGS(r10)
|
|
l.andi r3,r5,_TIF_NEED_RESCHED
|
|
l.sfnei r3,0
|
|
l.bnf _work_notifysig
|
|
l.nop
|
|
l.jal schedule
|
|
l.nop
|
|
l.j _resume_userspace
|
|
l.nop
|
|
|
|
/* Handle pending signals and notify-resume requests.
|
|
* do_notify_resume must be passed the latest pushed pt_regs, not
|
|
* necessarily the "userspace" ones. Also, pt_regs->syscallno
|
|
* must be set so that the syscall restart functionality works.
|
|
*/
|
|
_work_notifysig:
|
|
l.jal do_notify_resume
|
|
l.ori r3,r1,0 /* pt_regs */
|
|
|
|
_resume_userspace:
|
|
DISABLE_INTERRUPTS(r3,r4)
|
|
l.lwz r3,TI_FLAGS(r10)
|
|
l.andi r3,r3,_TIF_WORK_MASK
|
|
l.sfnei r3,0
|
|
l.bf _work_pending
|
|
l.nop
|
|
|
|
_restore_all:
|
|
RESTORE_ALL
|
|
/* This returns to userspace code */
|
|
|
|
|
|
ENTRY(_ret_from_intr)
|
|
ENTRY(_ret_from_exception)
|
|
l.lwz r4,PT_SR(r1)
|
|
l.andi r3,r4,SPR_SR_SM
|
|
l.sfeqi r3,0
|
|
l.bnf _restore_all
|
|
l.nop
|
|
l.j _resume_userspace
|
|
l.nop
|
|
|
|
ENTRY(ret_from_fork)
|
|
l.jal schedule_tail
|
|
l.nop
|
|
|
|
/* Check if we are a kernel thread */
|
|
l.sfeqi r20,0
|
|
l.bf 1f
|
|
l.nop
|
|
|
|
/* ...we are a kernel thread so invoke the requested callback */
|
|
l.jalr r20
|
|
l.or r3,r22,r0
|
|
|
|
1:
|
|
/* _syscall_returns expect r11 to contain return value */
|
|
l.lwz r11,PT_GPR11(r1)
|
|
|
|
/* The syscall fast path return expects call-saved registers
|
|
* r12-r28 to be untouched, so we restore them here as they
|
|
* will have been effectively clobbered when arriving here
|
|
* via the call to switch()
|
|
*/
|
|
l.lwz r12,PT_GPR12(r1)
|
|
l.lwz r14,PT_GPR14(r1)
|
|
l.lwz r16,PT_GPR16(r1)
|
|
l.lwz r18,PT_GPR18(r1)
|
|
l.lwz r20,PT_GPR20(r1)
|
|
l.lwz r22,PT_GPR22(r1)
|
|
l.lwz r24,PT_GPR24(r1)
|
|
l.lwz r26,PT_GPR26(r1)
|
|
l.lwz r28,PT_GPR28(r1)
|
|
|
|
l.j _syscall_return
|
|
l.nop
|
|
|
|
/* ========================================================[ switch ] === */
|
|
|
|
/*
|
|
* This routine switches between two different tasks. The process
|
|
* state of one is saved on its kernel stack. Then the state
|
|
* of the other is restored from its kernel stack. The memory
|
|
* management hardware is updated to the second process's state.
|
|
* Finally, we can return to the second process, via the 'return'.
|
|
*
|
|
* Note: there are two ways to get to the "going out" portion
|
|
* of this code; either by coming in via the entry (_switch)
|
|
* or via "fork" which must set up an environment equivalent
|
|
* to the "_switch" path. If you change this (or in particular, the
|
|
* SAVE_REGS macro), you'll have to change the fork code also.
|
|
*/
|
|
|
|
|
|
/* _switch MUST never lay on page boundry, cause it runs from
|
|
* effective addresses and beeing interrupted by iTLB miss would kill it.
|
|
* dTLB miss seams to never accour in the bad place since data accesses
|
|
* are from task structures which are always page aligned.
|
|
*
|
|
* The problem happens in RESTORE_ALL_NO_R11 where we first set the EPCR
|
|
* register, then load the previous register values and only at the end call
|
|
* the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets
|
|
* garbled and we end up calling l.rfe with the wrong EPCR. (same probably
|
|
* holds for ESR)
|
|
*
|
|
* To avoid this problems it is sufficient to align _switch to
|
|
* some nice round number smaller than it's size...
|
|
*/
|
|
|
|
/* ABI rules apply here... we either enter _switch via schedule() or via
|
|
* an imaginary call to which we shall return at return_from_fork. Either
|
|
* way, we are a function call and only need to preserve the callee-saved
|
|
* registers when we return. As such, we don't need to save the registers
|
|
* on the stack that we won't be returning as they were...
|
|
*/
|
|
|
|
.align 0x400
|
|
ENTRY(_switch)
|
|
/* We don't store SR as _switch only gets called in a context where
|
|
* the SR will be the same going in and coming out... */
|
|
|
|
/* Set up new pt_regs struct for saving task state */
|
|
l.addi r1,r1,-(INT_FRAME_SIZE)
|
|
|
|
/* No need to store r1/PT_SP as it goes into KSP below */
|
|
l.sw PT_GPR2(r1),r2
|
|
l.sw PT_GPR9(r1),r9
|
|
/* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
|
|
* and expects r12 to be callee-saved... */
|
|
l.sw PT_GPR12(r1),r12
|
|
l.sw PT_GPR14(r1),r14
|
|
l.sw PT_GPR16(r1),r16
|
|
l.sw PT_GPR18(r1),r18
|
|
l.sw PT_GPR20(r1),r20
|
|
l.sw PT_GPR22(r1),r22
|
|
l.sw PT_GPR24(r1),r24
|
|
l.sw PT_GPR26(r1),r26
|
|
l.sw PT_GPR28(r1),r28
|
|
l.sw PT_GPR30(r1),r30
|
|
|
|
l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/
|
|
|
|
/* We use thread_info->ksp for storing the address of the above
|
|
* structure so that we can get back to it later... we don't want
|
|
* to lose the value of thread_info->ksp, though, so store it as
|
|
* pt_regs->sp so that we can easily restore it when we are made
|
|
* live again...
|
|
*/
|
|
|
|
/* Save the old value of thread_info->ksp as pt_regs->sp */
|
|
l.lwz r29,TI_KSP(r10)
|
|
l.sw PT_SP(r1),r29
|
|
|
|
/* Swap kernel stack pointers */
|
|
l.sw TI_KSP(r10),r1 /* Save old stack pointer */
|
|
l.or r10,r4,r0 /* Set up new current_thread_info */
|
|
l.lwz r1,TI_KSP(r10) /* Load new stack pointer */
|
|
|
|
/* Restore the old value of thread_info->ksp */
|
|
l.lwz r29,PT_SP(r1)
|
|
l.sw TI_KSP(r10),r29
|
|
|
|
/* ...and restore the registers, except r11 because the return value
|
|
* has already been set above.
|
|
*/
|
|
l.lwz r2,PT_GPR2(r1)
|
|
l.lwz r9,PT_GPR9(r1)
|
|
/* No need to restore r10 */
|
|
/* ...and do not restore r11 */
|
|
|
|
/* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
|
|
* and expects r12 to be callee-saved... */
|
|
l.lwz r12,PT_GPR12(r1)
|
|
l.lwz r14,PT_GPR14(r1)
|
|
l.lwz r16,PT_GPR16(r1)
|
|
l.lwz r18,PT_GPR18(r1)
|
|
l.lwz r20,PT_GPR20(r1)
|
|
l.lwz r22,PT_GPR22(r1)
|
|
l.lwz r24,PT_GPR24(r1)
|
|
l.lwz r26,PT_GPR26(r1)
|
|
l.lwz r28,PT_GPR28(r1)
|
|
l.lwz r30,PT_GPR30(r1)
|
|
|
|
/* Unwind stack to pre-switch state */
|
|
l.addi r1,r1,(INT_FRAME_SIZE)
|
|
|
|
/* Return via the link-register back to where we 'came from', where
|
|
* that may be either schedule(), ret_from_fork(), or
|
|
* ret_from_kernel_thread(). If we are returning to a new thread,
|
|
* we are expected to have set up the arg to schedule_tail already,
|
|
* hence we do so here unconditionally:
|
|
*/
|
|
l.lwz r3,TI_STACK(r3) /* Load 'prev' as schedule_tail arg */
|
|
l.jr r9
|
|
l.nop
|
|
|
|
/* ==================================================================== */
|
|
|
|
/* These all use the delay slot for setting the argument register, so the
|
|
* jump is always happening after the l.addi instruction.
|
|
*
|
|
* These are all just wrappers that don't touch the link-register r9, so the
|
|
* return from the "real" syscall function will return back to the syscall
|
|
* code that did the l.jal that brought us here.
|
|
*/
|
|
|
|
/* fork requires that we save all the callee-saved registers because they
|
|
* are all effectively clobbered by the call to _switch. Here we store
|
|
* all the registers that aren't touched by the syscall fast path and thus
|
|
* weren't saved there.
|
|
*/
|
|
|
|
_fork_save_extra_regs_and_call:
|
|
l.sw PT_GPR14(r1),r14
|
|
l.sw PT_GPR16(r1),r16
|
|
l.sw PT_GPR18(r1),r18
|
|
l.sw PT_GPR20(r1),r20
|
|
l.sw PT_GPR22(r1),r22
|
|
l.sw PT_GPR24(r1),r24
|
|
l.sw PT_GPR26(r1),r26
|
|
l.jr r29
|
|
l.sw PT_GPR28(r1),r28
|
|
|
|
ENTRY(__sys_clone)
|
|
l.movhi r29,hi(sys_clone)
|
|
l.ori r29,r29,lo(sys_clone)
|
|
l.j _fork_save_extra_regs_and_call
|
|
l.addi r7,r1,0
|
|
|
|
ENTRY(__sys_fork)
|
|
l.movhi r29,hi(sys_fork)
|
|
l.ori r29,r29,lo(sys_fork)
|
|
l.j _fork_save_extra_regs_and_call
|
|
l.addi r3,r1,0
|
|
|
|
ENTRY(sys_sigaltstack)
|
|
l.j _sys_sigaltstack
|
|
l.addi r5,r1,0
|
|
|
|
ENTRY(sys_rt_sigreturn)
|
|
l.j _sys_rt_sigreturn
|
|
l.addi r3,r1,0
|
|
|
|
/* This is a catch-all syscall for atomic instructions for the OpenRISC 1000.
|
|
* The functions takes a variable number of parameters depending on which
|
|
* particular flavour of atomic you want... parameter 1 is a flag identifying
|
|
* the atomic in question. Currently, this function implements the
|
|
* following variants:
|
|
*
|
|
* XCHG:
|
|
* @flag: 1
|
|
* @ptr1:
|
|
* @ptr2:
|
|
* Atomically exchange the values in pointers 1 and 2.
|
|
*
|
|
*/
|
|
|
|
ENTRY(sys_or1k_atomic)
|
|
/* FIXME: This ignores r3 and always does an XCHG */
|
|
DISABLE_INTERRUPTS(r17,r19)
|
|
l.lwz r29,0(r4)
|
|
l.lwz r27,0(r5)
|
|
l.sw 0(r4),r27
|
|
l.sw 0(r5),r29
|
|
ENABLE_INTERRUPTS(r17)
|
|
l.jr r9
|
|
l.or r11,r0,r0
|
|
|
|
/* ============================================================[ EOF ]=== */
|