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10f67dbf6a
The mainline signal handling code for OpenRISC has been buggy since day
one with respect to syscall restart. This patch significantly reworks
the signal handling code:
i) Move the "work pending" loop to C code (borrowed from ARM arch)
ii) Allow a tracer to muck about with the IP and skip syscall restart
in that case (again, borrowed from ARM)
iii) Make signal handling WRT syscall restart actually work
v) Make the signal handling code look more like that of other
architectures so that it's easier for others to follow
Reported-by: Anders Nystrom <anders@southpole.se>
Signed-off-by: Jonas Bonn <jonas@southpole.se>
1133 lines
30 KiB
ArmAsm
1133 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(_dtlb_miss_page_fault_handler)
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l.and r5,r5,r0
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l.j 1f
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l.nop
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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.ori r5,r0,0x300 // exception vector
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1:
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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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/*
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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(_itlb_miss_page_fault_handler)
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l.and r5,r5,r0
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l.j 1f
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l.nop
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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.ori r5,r0,0x400 // exception vector
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1:
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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 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
|
|
l.sw 0(r4),r5
|
|
|
|
lwz: l.lbz r5,0(r2)
|
|
l.slli r5,r5,24
|
|
l.lbz r6,1(r2)
|
|
l.slli r6,r6,16
|
|
l.or r5,r5,r6
|
|
l.lbz r6,2(r2)
|
|
l.slli r6,r6,8
|
|
l.or r5,r5,r6
|
|
l.lbz r6,3(r2)
|
|
l.or r5,r5,r6
|
|
l.srli r4,r3,19
|
|
l.andi r4,r4,0x7c
|
|
l.add r4,r4,r1
|
|
l.j align_end
|
|
l.sw 0(r4),r5
|
|
|
|
sh:
|
|
l.srli r4,r3,9
|
|
l.andi r4,r4,0x7c
|
|
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 ] === */
|
|
|
|
_resume_userspace:
|
|
DISABLE_INTERRUPTS(r3,r4)
|
|
l.lwz r4,TI_FLAGS(r10)
|
|
l.andi r13,r4,_TIF_WORK_MASK
|
|
l.sfeqi r13,0
|
|
l.bf _restore_all
|
|
l.nop
|
|
|
|
_work_pending:
|
|
l.lwz r5,PT_ORIG_GPR11(r1)
|
|
l.sfltsi r5,0
|
|
l.bnf 1f
|
|
l.nop
|
|
l.andi r5,r5,0
|
|
1:
|
|
l.jal do_work_pending
|
|
l.ori r3,r1,0 /* pt_regs */
|
|
|
|
l.sfeqi r11,0
|
|
l.bf _restore_all
|
|
l.nop
|
|
l.sfltsi r11,0
|
|
l.bnf 1f
|
|
l.nop
|
|
l.and r11,r11,r0
|
|
l.ori r11,r11,__NR_restart_syscall
|
|
l.j _syscall_check_trace_enter
|
|
l.nop
|
|
1:
|
|
l.lwz r11,PT_ORIG_GPR11(r1)
|
|
/* Restore arg registers */
|
|
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_trace_enter
|
|
l.lwz r8,PT_GPR8(r1)
|
|
|
|
_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_TASK(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_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 ]=== */
|