OpenRISC: Boot code
Architecture code and early setup routines for booting Linux.
Signed-off-by: Jonas Bonn <jonas@southpole.se>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S
new file mode 100644
index 0000000..c75018d
--- /dev/null
+++ b/arch/openrisc/kernel/head.S
@@ -0,0 +1,1607 @@
+/*
+ * OpenRISC head.S
+ *
+ * Linux architectural port borrowing liberally from similar works of
+ * others. All original copyrights apply as per the original source
+ * declaration.
+ *
+ * Modifications for the OpenRISC architecture:
+ * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/linkage.h>
+#include <linux/threads.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/mmu.h>
+#include <asm/pgtable.h>
+#include <asm/cache.h>
+#include <asm/spr_defs.h>
+#include <asm/asm-offsets.h>
+
+#define tophys(rd,rs) \
+ l.movhi rd,hi(-KERNELBASE) ;\
+ l.add rd,rd,rs
+
+#define CLEAR_GPR(gpr) \
+ l.or gpr,r0,r0
+
+#define LOAD_SYMBOL_2_GPR(gpr,symbol) \
+ l.movhi gpr,hi(symbol) ;\
+ l.ori gpr,gpr,lo(symbol)
+
+
+#define UART_BASE_ADD 0x90000000
+
+#define EXCEPTION_SR (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_SM)
+#define SYSCALL_SR (SPR_SR_DME | SPR_SR_IME | SPR_SR_DCE | SPR_SR_ICE | SPR_SR_IEE | SPR_SR_TEE | SPR_SR_SM)
+
+/* ============================================[ tmp store locations ]=== */
+
+/*
+ * emergency_print temporary stores
+ */
+#define EMERGENCY_PRINT_STORE_GPR4 l.sw 0x20(r0),r4
+#define EMERGENCY_PRINT_LOAD_GPR4 l.lwz r4,0x20(r0)
+
+#define EMERGENCY_PRINT_STORE_GPR5 l.sw 0x24(r0),r5
+#define EMERGENCY_PRINT_LOAD_GPR5 l.lwz r5,0x24(r0)
+
+#define EMERGENCY_PRINT_STORE_GPR6 l.sw 0x28(r0),r6
+#define EMERGENCY_PRINT_LOAD_GPR6 l.lwz r6,0x28(r0)
+
+#define EMERGENCY_PRINT_STORE_GPR7 l.sw 0x2c(r0),r7
+#define EMERGENCY_PRINT_LOAD_GPR7 l.lwz r7,0x2c(r0)
+
+#define EMERGENCY_PRINT_STORE_GPR8 l.sw 0x30(r0),r8
+#define EMERGENCY_PRINT_LOAD_GPR8 l.lwz r8,0x30(r0)
+
+#define EMERGENCY_PRINT_STORE_GPR9 l.sw 0x34(r0),r9
+#define EMERGENCY_PRINT_LOAD_GPR9 l.lwz r9,0x34(r0)
+
+
+/*
+ * TLB miss handlers temorary stores
+ */
+#define EXCEPTION_STORE_GPR9 l.sw 0x10(r0),r9
+#define EXCEPTION_LOAD_GPR9 l.lwz r9,0x10(r0)
+
+#define EXCEPTION_STORE_GPR2 l.sw 0x64(r0),r2
+#define EXCEPTION_LOAD_GPR2 l.lwz r2,0x64(r0)
+
+#define EXCEPTION_STORE_GPR3 l.sw 0x68(r0),r3
+#define EXCEPTION_LOAD_GPR3 l.lwz r3,0x68(r0)
+
+#define EXCEPTION_STORE_GPR4 l.sw 0x6c(r0),r4
+#define EXCEPTION_LOAD_GPR4 l.lwz r4,0x6c(r0)
+
+#define EXCEPTION_STORE_GPR5 l.sw 0x70(r0),r5
+#define EXCEPTION_LOAD_GPR5 l.lwz r5,0x70(r0)
+
+#define EXCEPTION_STORE_GPR6 l.sw 0x74(r0),r6
+#define EXCEPTION_LOAD_GPR6 l.lwz r6,0x74(r0)
+
+
+/*
+ * EXCEPTION_HANDLE temporary stores
+ */
+
+#define EXCEPTION_T_STORE_GPR30 l.sw 0x78(r0),r30
+#define EXCEPTION_T_LOAD_GPR30(reg) l.lwz reg,0x78(r0)
+
+#define EXCEPTION_T_STORE_GPR10 l.sw 0x7c(r0),r10
+#define EXCEPTION_T_LOAD_GPR10(reg) l.lwz reg,0x7c(r0)
+
+#define EXCEPTION_T_STORE_SP l.sw 0x80(r0),r1
+#define EXCEPTION_T_LOAD_SP(reg) l.lwz reg,0x80(r0)
+
+/*
+ * For UNHANLDED_EXCEPTION
+ */
+
+#define EXCEPTION_T_STORE_GPR31 l.sw 0x84(r0),r31
+#define EXCEPTION_T_LOAD_GPR31(reg) l.lwz reg,0x84(r0)
+
+/* =========================================================[ macros ]=== */
+
+
+#define GET_CURRENT_PGD(reg,t1) \
+ LOAD_SYMBOL_2_GPR(reg,current_pgd) ;\
+ tophys (t1,reg) ;\
+ l.lwz reg,0(t1)
+
+
+/*
+ * DSCR: this is a common hook for handling exceptions. it will save
+ * the needed registers, set up stack and pointer to current
+ * then jump to the handler while enabling MMU
+ *
+ * PRMS: handler - a function to jump to. it has to save the
+ * remaining registers to kernel stack, call
+ * appropriate arch-independant exception handler
+ * and finaly jump to ret_from_except
+ *
+ * PREQ: unchanged state from the time exception happened
+ *
+ * POST: SAVED the following registers original value
+ * to the new created exception frame pointed to by r1
+ *
+ * r1 - ksp pointing to the new (exception) frame
+ * r4 - EEAR exception EA
+ * r10 - current pointing to current_thread_info struct
+ * r12 - syscall 0, since we didn't come from syscall
+ * r13 - temp it actually contains new SR, not needed anymore
+ * r31 - handler address of the handler we'll jump to
+ *
+ * handler has to save remaining registers to the exception
+ * ksp frame *before* tainting them!
+ *
+ * NOTE: this function is not reentrant per se. reentrancy is guaranteed
+ * by processor disabling all exceptions/interrupts when exception
+ * accours.
+ *
+ * OPTM: no need to make it so wasteful to extract ksp when in user mode
+ */
+
+#define EXCEPTION_HANDLE(handler) \
+ EXCEPTION_T_STORE_GPR30 ;\
+ l.mfspr r30,r0,SPR_ESR_BASE ;\
+ l.andi r30,r30,SPR_SR_SM ;\
+ l.sfeqi r30,0 ;\
+ EXCEPTION_T_STORE_GPR10 ;\
+ l.bnf 2f /* kernel_mode */ ;\
+ EXCEPTION_T_STORE_SP /* delay slot */ ;\
+1: /* user_mode: */ ;\
+ LOAD_SYMBOL_2_GPR(r1,current_thread_info_set) ;\
+ tophys (r30,r1) ;\
+ /* r10: current_thread_info */ ;\
+ l.lwz r10,0(r30) ;\
+ tophys (r30,r10) ;\
+ l.lwz r1,(TI_KSP)(r30) ;\
+ /* fall through */ ;\
+2: /* kernel_mode: */ ;\
+ /* create new stack frame, save only needed gprs */ ;\
+ /* r1: KSP, r10: current, r4: EEAR, r31: __pa(KSP) */ ;\
+ /* r12: temp, syscall indicator */ ;\
+ l.addi r1,r1,-(INT_FRAME_SIZE) ;\
+ /* r1 is KSP, r30 is __pa(KSP) */ ;\
+ tophys (r30,r1) ;\
+ l.sw PT_GPR12(r30),r12 ;\
+ l.mfspr r12,r0,SPR_EPCR_BASE ;\
+ l.sw PT_PC(r30),r12 ;\
+ l.mfspr r12,r0,SPR_ESR_BASE ;\
+ l.sw PT_SR(r30),r12 ;\
+ /* save r30 */ ;\
+ EXCEPTION_T_LOAD_GPR30(r12) ;\
+ l.sw PT_GPR30(r30),r12 ;\
+ /* save r10 as was prior to exception */ ;\
+ EXCEPTION_T_LOAD_GPR10(r12) ;\
+ l.sw PT_GPR10(r30),r12 ;\
+ /* save PT_SP as was prior to exception */ ;\
+ EXCEPTION_T_LOAD_SP(r12) ;\
+ l.sw PT_SP(r30),r12 ;\
+ /* save exception r4, set r4 = EA */ ;\
+ l.sw PT_GPR4(r30),r4 ;\
+ l.mfspr r4,r0,SPR_EEAR_BASE ;\
+ /* r12 == 1 if we come from syscall */ ;\
+ CLEAR_GPR(r12) ;\
+ /* ----- turn on MMU ----- */ ;\
+ l.ori r30,r0,(EXCEPTION_SR) ;\
+ l.mtspr r0,r30,SPR_ESR_BASE ;\
+ /* r30: EA address of handler */ ;\
+ LOAD_SYMBOL_2_GPR(r30,handler) ;\
+ l.mtspr r0,r30,SPR_EPCR_BASE ;\
+ l.rfe
+
+/*
+ * this doesn't work
+ *
+ *
+ * #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
+ * #define UNHANDLED_EXCEPTION(handler) \
+ * l.ori r3,r0,0x1 ;\
+ * l.mtspr r0,r3,SPR_SR ;\
+ * l.movhi r3,hi(0xf0000100) ;\
+ * l.ori r3,r3,lo(0xf0000100) ;\
+ * l.jr r3 ;\
+ * l.nop 1
+ *
+ * #endif
+ */
+
+/* DSCR: this is the same as EXCEPTION_HANDLE(), we are just
+ * a bit more carefull (if we have a PT_SP or current pointer
+ * corruption) and set them up from 'current_set'
+ *
+ */
+#define UNHANDLED_EXCEPTION(handler) \
+ EXCEPTION_T_STORE_GPR31 ;\
+ EXCEPTION_T_STORE_GPR10 ;\
+ EXCEPTION_T_STORE_SP ;\
+ /* temporary store r3, r9 into r1, r10 */ ;\
+ l.addi r1,r3,0x0 ;\
+ l.addi r10,r9,0x0 ;\
+ /* the string referenced by r3 must be low enough */ ;\
+ l.jal _emergency_print ;\
+ l.ori r3,r0,lo(_string_unhandled_exception) ;\
+ l.mfspr r3,r0,SPR_NPC ;\
+ l.jal _emergency_print_nr ;\
+ l.andi r3,r3,0x1f00 ;\
+ /* the string referenced by r3 must be low enough */ ;\
+ l.jal _emergency_print ;\
+ l.ori r3,r0,lo(_string_epc_prefix) ;\
+ l.jal _emergency_print_nr ;\
+ l.mfspr r3,r0,SPR_EPCR_BASE ;\
+ l.jal _emergency_print ;\
+ l.ori r3,r0,lo(_string_nl) ;\
+ /* end of printing */ ;\
+ l.addi r3,r1,0x0 ;\
+ l.addi r9,r10,0x0 ;\
+ /* extract current, ksp from current_set */ ;\
+ LOAD_SYMBOL_2_GPR(r1,_unhandled_stack_top) ;\
+ LOAD_SYMBOL_2_GPR(r10,init_thread_union) ;\
+ /* create new stack frame, save only needed gprs */ ;\
+ /* r1: KSP, r10: current, r31: __pa(KSP) */ ;\
+ /* r12: temp, syscall indicator, r13 temp */ ;\
+ l.addi r1,r1,-(INT_FRAME_SIZE) ;\
+ /* r1 is KSP, r31 is __pa(KSP) */ ;\
+ tophys (r31,r1) ;\
+ l.sw PT_GPR12(r31),r12 ;\
+ l.mfspr r12,r0,SPR_EPCR_BASE ;\
+ l.sw PT_PC(r31),r12 ;\
+ l.mfspr r12,r0,SPR_ESR_BASE ;\
+ l.sw PT_SR(r31),r12 ;\
+ /* save r31 */ ;\
+ EXCEPTION_T_LOAD_GPR31(r12) ;\
+ l.sw PT_GPR31(r31),r12 ;\
+ /* save r10 as was prior to exception */ ;\
+ EXCEPTION_T_LOAD_GPR10(r12) ;\
+ l.sw PT_GPR10(r31),r12 ;\
+ /* save PT_SP as was prior to exception */ ;\
+ EXCEPTION_T_LOAD_SP(r12) ;\
+ l.sw PT_SP(r31),r12 ;\
+ l.sw PT_GPR13(r31),r13 ;\
+ /* --> */ ;\
+ /* save exception r4, set r4 = EA */ ;\
+ l.sw PT_GPR4(r31),r4 ;\
+ l.mfspr r4,r0,SPR_EEAR_BASE ;\
+ /* r12 == 1 if we come from syscall */ ;\
+ CLEAR_GPR(r12) ;\
+ /* ----- play a MMU trick ----- */ ;\
+ l.ori r31,r0,(EXCEPTION_SR) ;\
+ l.mtspr r0,r31,SPR_ESR_BASE ;\
+ /* r31: EA address of handler */ ;\
+ LOAD_SYMBOL_2_GPR(r31,handler) ;\
+ l.mtspr r0,r31,SPR_EPCR_BASE ;\
+ l.rfe
+
+/* =====================================================[ exceptions] === */
+
+/* ---[ 0x100: RESET exception ]----------------------------------------- */
+ .org 0x100
+ /* Jump to .init code at _start which lives in the .head section
+ * and will be discarded after boot.
+ */
+ LOAD_SYMBOL_2_GPR(r4, _start)
+ tophys (r3,r4) /* MMU disabled */
+ l.jr r3
+ l.nop
+
+/* ---[ 0x200: BUS exception ]------------------------------------------- */
+ .org 0x200
+_dispatch_bus_fault:
+ EXCEPTION_HANDLE(_bus_fault_handler)
+
+/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
+ .org 0x300
+_dispatch_do_dpage_fault:
+// totaly disable timer interrupt
+// l.mtspr r0,r0,SPR_TTMR
+// DEBUG_TLB_PROBE(0x300)
+// EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x300)
+ EXCEPTION_HANDLE(_data_page_fault_handler)
+
+/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
+ .org 0x400
+_dispatch_do_ipage_fault:
+// totaly disable timer interrupt
+// l.mtspr r0,r0,SPR_TTMR
+// DEBUG_TLB_PROBE(0x400)
+// EXCEPTION_DEBUG_VALUE_ER_ENABLED(0x400)
+ EXCEPTION_HANDLE(_insn_page_fault_handler)
+
+/* ---[ 0x500: Timer exception ]----------------------------------------- */
+ .org 0x500
+ EXCEPTION_HANDLE(_timer_handler)
+
+/* ---[ 0x600: Aligment exception ]-------------------------------------- */
+ .org 0x600
+ EXCEPTION_HANDLE(_alignment_handler)
+
+/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
+ .org 0x700
+ EXCEPTION_HANDLE(_illegal_instruction_handler)
+
+/* ---[ 0x800: External interrupt exception ]---------------------------- */
+ .org 0x800
+ EXCEPTION_HANDLE(_external_irq_handler)
+
+/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
+ .org 0x900
+ l.j boot_dtlb_miss_handler
+ l.nop
+
+/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
+ .org 0xa00
+ l.j boot_itlb_miss_handler
+ l.nop
+
+/* ---[ 0xb00: Range exception ]----------------------------------------- */
+ .org 0xb00
+ UNHANDLED_EXCEPTION(_vector_0xb00)
+
+/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
+ .org 0xc00
+ EXCEPTION_HANDLE(_sys_call_handler)
+
+/* ---[ 0xd00: Trap exception ]------------------------------------------ */
+ .org 0xd00
+ UNHANDLED_EXCEPTION(_vector_0xd00)
+
+/* ---[ 0xe00: Trap exception ]------------------------------------------ */
+ .org 0xe00
+// UNHANDLED_EXCEPTION(_vector_0xe00)
+ EXCEPTION_HANDLE(_trap_handler)
+
+/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
+ .org 0xf00
+ UNHANDLED_EXCEPTION(_vector_0xf00)
+
+/* ---[ 0x1000: Reserved exception ]------------------------------------- */
+ .org 0x1000
+ UNHANDLED_EXCEPTION(_vector_0x1000)
+
+/* ---[ 0x1100: Reserved exception ]------------------------------------- */
+ .org 0x1100
+ UNHANDLED_EXCEPTION(_vector_0x1100)
+
+/* ---[ 0x1200: Reserved exception ]------------------------------------- */
+ .org 0x1200
+ UNHANDLED_EXCEPTION(_vector_0x1200)
+
+/* ---[ 0x1300: Reserved exception ]------------------------------------- */
+ .org 0x1300
+ UNHANDLED_EXCEPTION(_vector_0x1300)
+
+/* ---[ 0x1400: Reserved exception ]------------------------------------- */
+ .org 0x1400
+ UNHANDLED_EXCEPTION(_vector_0x1400)
+
+/* ---[ 0x1500: Reserved exception ]------------------------------------- */
+ .org 0x1500
+ UNHANDLED_EXCEPTION(_vector_0x1500)
+
+/* ---[ 0x1600: Reserved exception ]------------------------------------- */
+ .org 0x1600
+ UNHANDLED_EXCEPTION(_vector_0x1600)
+
+/* ---[ 0x1700: Reserved exception ]------------------------------------- */
+ .org 0x1700
+ UNHANDLED_EXCEPTION(_vector_0x1700)
+
+/* ---[ 0x1800: Reserved exception ]------------------------------------- */
+ .org 0x1800
+ UNHANDLED_EXCEPTION(_vector_0x1800)
+
+/* ---[ 0x1900: Reserved exception ]------------------------------------- */
+ .org 0x1900
+ UNHANDLED_EXCEPTION(_vector_0x1900)
+
+/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
+ .org 0x1a00
+ UNHANDLED_EXCEPTION(_vector_0x1a00)
+
+/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
+ .org 0x1b00
+ UNHANDLED_EXCEPTION(_vector_0x1b00)
+
+/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
+ .org 0x1c00
+ UNHANDLED_EXCEPTION(_vector_0x1c00)
+
+/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
+ .org 0x1d00
+ UNHANDLED_EXCEPTION(_vector_0x1d00)
+
+/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
+ .org 0x1e00
+ UNHANDLED_EXCEPTION(_vector_0x1e00)
+
+/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
+ .org 0x1f00
+ UNHANDLED_EXCEPTION(_vector_0x1f00)
+
+ .org 0x2000
+/* ===================================================[ kernel start ]=== */
+
+/* .text*/
+
+/* This early stuff belongs in HEAD, but some of the functions below definitely
+ * don't... */
+
+ __HEAD
+ .global _start
+_start:
+ /*
+ * ensure a deterministic start
+ */
+
+ l.ori r3,r0,0x1
+ l.mtspr r0,r3,SPR_SR
+
+ CLEAR_GPR(r1)
+ CLEAR_GPR(r2)
+ CLEAR_GPR(r3)
+ CLEAR_GPR(r4)
+ CLEAR_GPR(r5)
+ CLEAR_GPR(r6)
+ CLEAR_GPR(r7)
+ CLEAR_GPR(r8)
+ CLEAR_GPR(r9)
+ CLEAR_GPR(r10)
+ CLEAR_GPR(r11)
+ CLEAR_GPR(r12)
+ CLEAR_GPR(r13)
+ CLEAR_GPR(r14)
+ CLEAR_GPR(r15)
+ CLEAR_GPR(r16)
+ CLEAR_GPR(r17)
+ CLEAR_GPR(r18)
+ CLEAR_GPR(r19)
+ CLEAR_GPR(r20)
+ CLEAR_GPR(r21)
+ CLEAR_GPR(r22)
+ CLEAR_GPR(r23)
+ CLEAR_GPR(r24)
+ CLEAR_GPR(r25)
+ CLEAR_GPR(r26)
+ CLEAR_GPR(r27)
+ CLEAR_GPR(r28)
+ CLEAR_GPR(r29)
+ CLEAR_GPR(r30)
+ CLEAR_GPR(r31)
+
+ /*
+ * set up initial ksp and current
+ */
+ LOAD_SYMBOL_2_GPR(r1,init_thread_union+0x2000) // setup kernel stack
+ LOAD_SYMBOL_2_GPR(r10,init_thread_union) // setup current
+ tophys (r31,r10)
+ l.sw TI_KSP(r31), r1
+
+ l.ori r4,r0,0x0
+
+
+ /*
+ * .data contains initialized data,
+ * .bss contains uninitialized data - clear it up
+ */
+clear_bss:
+ LOAD_SYMBOL_2_GPR(r24, __bss_start)
+ LOAD_SYMBOL_2_GPR(r26, _end)
+ tophys(r28,r24)
+ tophys(r30,r26)
+ CLEAR_GPR(r24)
+ CLEAR_GPR(r26)
+1:
+ l.sw (0)(r28),r0
+ l.sfltu r28,r30
+ l.bf 1b
+ l.addi r28,r28,4
+
+enable_ic:
+ l.jal _ic_enable
+ l.nop
+
+enable_dc:
+ l.jal _dc_enable
+ l.nop
+
+flush_tlb:
+ /*
+ * I N V A L I D A T E T L B e n t r i e s
+ */
+ LOAD_SYMBOL_2_GPR(r5,SPR_DTLBMR_BASE(0))
+ LOAD_SYMBOL_2_GPR(r6,SPR_ITLBMR_BASE(0))
+ l.addi r7,r0,128 /* Maximum number of sets */
+1:
+ l.mtspr r5,r0,0x0
+ l.mtspr r6,r0,0x0
+
+ l.addi r5,r5,1
+ l.addi r6,r6,1
+ l.sfeq r7,r0
+ l.bnf 1b
+ l.addi r7,r7,-1
+
+
+/* The MMU needs to be enabled before or32_early_setup is called */
+
+enable_mmu:
+ /*
+ * enable dmmu & immu
+ * SR[5] = 0, SR[6] = 0, 6th and 7th bit of SR set to 0
+ */
+ l.mfspr r30,r0,SPR_SR
+ l.movhi r28,hi(SPR_SR_DME | SPR_SR_IME)
+ l.ori r28,r28,lo(SPR_SR_DME | SPR_SR_IME)
+ l.or r30,r30,r28
+ l.mtspr r0,r30,SPR_SR
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+
+ // reset the simulation counters
+ l.nop 5
+
+ LOAD_SYMBOL_2_GPR(r24, or32_early_setup)
+ l.jalr r24
+ l.nop
+
+clear_regs:
+ /*
+ * clear all GPRS to increase determinism
+ */
+ CLEAR_GPR(r2)
+ CLEAR_GPR(r3)
+ CLEAR_GPR(r4)
+ CLEAR_GPR(r5)
+ CLEAR_GPR(r6)
+ CLEAR_GPR(r7)
+ CLEAR_GPR(r8)
+ CLEAR_GPR(r9)
+ CLEAR_GPR(r11)
+ CLEAR_GPR(r12)
+ CLEAR_GPR(r13)
+ CLEAR_GPR(r14)
+ CLEAR_GPR(r15)
+ CLEAR_GPR(r16)
+ CLEAR_GPR(r17)
+ CLEAR_GPR(r18)
+ CLEAR_GPR(r19)
+ CLEAR_GPR(r20)
+ CLEAR_GPR(r21)
+ CLEAR_GPR(r22)
+ CLEAR_GPR(r23)
+ CLEAR_GPR(r24)
+ CLEAR_GPR(r25)
+ CLEAR_GPR(r26)
+ CLEAR_GPR(r27)
+ CLEAR_GPR(r28)
+ CLEAR_GPR(r29)
+ CLEAR_GPR(r30)
+ CLEAR_GPR(r31)
+
+jump_start_kernel:
+ /*
+ * jump to kernel entry (start_kernel)
+ */
+ LOAD_SYMBOL_2_GPR(r30, start_kernel)
+ l.jr r30
+ l.nop
+
+/* ========================================[ cache ]=== */
+
+ /* aligment here so we don't change memory offsets with
+ * memory controler defined
+ */
+ .align 0x2000
+
+_ic_enable:
+ /* Check if IC present and skip enabling otherwise */
+ l.mfspr r24,r0,SPR_UPR
+ l.andi r26,r24,SPR_UPR_ICP
+ l.sfeq r26,r0
+ l.bf 9f
+ l.nop
+
+ /* Disable IC */
+ l.mfspr r6,r0,SPR_SR
+ l.addi r5,r0,-1
+ l.xori r5,r5,SPR_SR_ICE
+ l.and r5,r6,r5
+ l.mtspr r0,r5,SPR_SR
+
+ /* Establish cache block size
+ If BS=0, 16;
+ If BS=1, 32;
+ r14 contain block size
+ */
+ l.mfspr r24,r0,SPR_ICCFGR
+ l.andi r26,r24,SPR_ICCFGR_CBS
+ l.srli r28,r26,7
+ l.ori r30,r0,16
+ l.sll r14,r30,r28
+
+ /* Establish number of cache sets
+ r16 contains number of cache sets
+ r28 contains log(# of cache sets)
+ */
+ l.andi r26,r24,SPR_ICCFGR_NCS
+ l.srli r28,r26,3
+ l.ori r30,r0,1
+ l.sll r16,r30,r28
+
+ /* Invalidate IC */
+ l.addi r6,r0,0
+ l.sll r5,r14,r28
+// l.mul r5,r14,r16
+// l.trap 1
+// l.addi r5,r0,IC_SIZE
+1:
+ l.mtspr r0,r6,SPR_ICBIR
+ l.sfne r6,r5
+ l.bf 1b
+ l.add r6,r6,r14
+ // l.addi r6,r6,IC_LINE
+
+ /* Enable IC */
+ l.mfspr r6,r0,SPR_SR
+ l.ori r6,r6,SPR_SR_ICE
+ l.mtspr r0,r6,SPR_SR
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+ l.nop
+9:
+ l.jr r9
+ l.nop
+
+_dc_enable:
+ /* Check if DC present and skip enabling otherwise */
+ l.mfspr r24,r0,SPR_UPR
+ l.andi r26,r24,SPR_UPR_DCP
+ l.sfeq r26,r0
+ l.bf 9f
+ l.nop
+
+ /* Disable DC */
+ l.mfspr r6,r0,SPR_SR
+ l.addi r5,r0,-1
+ l.xori r5,r5,SPR_SR_DCE
+ l.and r5,r6,r5
+ l.mtspr r0,r5,SPR_SR
+
+ /* Establish cache block size
+ If BS=0, 16;
+ If BS=1, 32;
+ r14 contain block size
+ */
+ l.mfspr r24,r0,SPR_DCCFGR
+ l.andi r26,r24,SPR_DCCFGR_CBS
+ l.srli r28,r26,7
+ l.ori r30,r0,16
+ l.sll r14,r30,r28
+
+ /* Establish number of cache sets
+ r16 contains number of cache sets
+ r28 contains log(# of cache sets)
+ */
+ l.andi r26,r24,SPR_DCCFGR_NCS
+ l.srli r28,r26,3
+ l.ori r30,r0,1
+ l.sll r16,r30,r28
+
+ /* Invalidate DC */
+ l.addi r6,r0,0
+ l.sll r5,r14,r28
+1:
+ l.mtspr r0,r6,SPR_DCBIR
+ l.sfne r6,r5
+ l.bf 1b
+ l.add r6,r6,r14
+
+ /* Enable DC */
+ l.mfspr r6,r0,SPR_SR
+ l.ori r6,r6,SPR_SR_DCE
+ l.mtspr r0,r6,SPR_SR
+9:
+ l.jr r9
+ l.nop
+
+/* ===============================================[ page table masks ]=== */
+
+/* bit 4 is used in hardware as write back cache bit. we never use this bit
+ * explicitly, so we can reuse it as _PAGE_FILE bit and mask it out when
+ * writing into hardware pte's
+ */
+
+#define DTLB_UP_CONVERT_MASK 0x3fa
+#define ITLB_UP_CONVERT_MASK 0x3a
+
+/* for SMP we'd have (this is a bit subtle, CC must be always set
+ * for SMP, but since we have _PAGE_PRESENT bit always defined
+ * we can just modify the mask)
+ */
+#define DTLB_SMP_CONVERT_MASK 0x3fb
+#define ITLB_SMP_CONVERT_MASK 0x3b
+
+/* ---[ boot dtlb miss handler ]----------------------------------------- */
+
+boot_dtlb_miss_handler:
+
+/* mask for DTLB_MR register: - (0) sets V (valid) bit,
+ * - (31-12) sets bits belonging to VPN (31-12)
+ */
+#define DTLB_MR_MASK 0xfffff001
+
+/* mask for DTLB_TR register: - (2) sets CI (cache inhibit) bit,
+ * - (4) sets A (access) bit,
+ * - (5) sets D (dirty) bit,
+ * - (8) sets SRE (superuser read) bit
+ * - (9) sets SWE (superuser write) bit
+ * - (31-12) sets bits belonging to VPN (31-12)
+ */
+#define DTLB_TR_MASK 0xfffff332
+
+/* These are for masking out the VPN/PPN value from the MR/TR registers...
+ * it's not the same as the PFN */
+#define VPN_MASK 0xfffff000
+#define PPN_MASK 0xfffff000
+
+
+ EXCEPTION_STORE_GPR6
+
+#if 0
+ l.mfspr r6,r0,SPR_ESR_BASE //
+ l.andi r6,r6,SPR_SR_SM // are we in kernel mode ?
+ l.sfeqi r6,0 // r6 == 0x1 --> SM
+ l.bf exit_with_no_dtranslation //
+ l.nop
+#endif
+
+ /* this could be optimized by moving storing of
+ * non r6 registers here, and jumping r6 restore
+ * if not in supervisor mode
+ */
+
+ EXCEPTION_STORE_GPR2
+ EXCEPTION_STORE_GPR3
+ EXCEPTION_STORE_GPR4
+ EXCEPTION_STORE_GPR5
+
+ l.mfspr r4,r0,SPR_EEAR_BASE // get the offending EA
+
+immediate_translation:
+ CLEAR_GPR(r6)
+
+ l.srli r3,r4,0xd // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
+
+ l.mfspr r6, r0, SPR_DMMUCFGR
+ l.andi r6, r6, SPR_DMMUCFGR_NTS
+ l.srli r6, r6, SPR_DMMUCFGR_NTS_OFF
+ l.ori r5, r0, 0x1
+ l.sll r5, r5, r6 // r5 = number DMMU sets
+ l.addi r6, r5, -1 // r6 = nsets mask
+ l.and r2, r3, r6 // r2 <- r3 % NSETS_MASK
+
+ l.or r6,r6,r4 // r6 <- r4
+ l.ori r6,r6,~(VPN_MASK) // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
+ l.movhi r5,hi(DTLB_MR_MASK) // r5 <- ffff:0000.x000
+ l.ori r5,r5,lo(DTLB_MR_MASK) // r5 <- ffff:1111.x001 - apply DTLB_MR_MASK
+ l.and r5,r5,r6 // r5 <- VPN :VPN .x001 - we have DTLBMR entry
+ l.mtspr r2,r5,SPR_DTLBMR_BASE(0) // set DTLBMR
+
+ /* set up DTLB with no translation for EA <= 0xbfffffff */
+ LOAD_SYMBOL_2_GPR(r6,0xbfffffff)
+ l.sfgeu r6,r4 // flag if r6 >= r4 (if 0xbfffffff >= EA)
+ l.bf 1f // goto out
+ l.and r3,r4,r4 // delay slot :: 24 <- r4 (if flag==1)
+
+ tophys(r3,r4) // r3 <- PA
+1:
+ l.ori r3,r3,~(PPN_MASK) // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
+ l.movhi r5,hi(DTLB_TR_MASK) // r5 <- ffff:0000.x000
+ l.ori r5,r5,lo(DTLB_TR_MASK) // r5 <- ffff:1111.x330 - apply DTLB_MR_MASK
+ l.and r5,r5,r3 // r5 <- PPN :PPN .x330 - we have DTLBTR entry
+ l.mtspr r2,r5,SPR_DTLBTR_BASE(0) // set DTLBTR
+
+ EXCEPTION_LOAD_GPR6
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR2
+
+ l.rfe // SR <- ESR, PC <- EPC
+
+exit_with_no_dtranslation:
+ /* EA out of memory or not in supervisor mode */
+ EXCEPTION_LOAD_GPR6
+ EXCEPTION_LOAD_GPR4
+ l.j _dispatch_bus_fault
+
+/* ---[ boot itlb miss handler ]----------------------------------------- */
+
+boot_itlb_miss_handler:
+
+/* mask for ITLB_MR register: - sets V (valid) bit,
+ * - sets bits belonging to VPN (15-12)
+ */
+#define ITLB_MR_MASK 0xfffff001
+
+/* mask for ITLB_TR register: - sets A (access) bit,
+ * - sets SXE (superuser execute) bit
+ * - sets bits belonging to VPN (15-12)
+ */
+#define ITLB_TR_MASK 0xfffff050
+
+/*
+#define VPN_MASK 0xffffe000
+#define PPN_MASK 0xffffe000
+*/
+
+
+
+ EXCEPTION_STORE_GPR2
+ EXCEPTION_STORE_GPR3
+ EXCEPTION_STORE_GPR4
+ EXCEPTION_STORE_GPR5
+ EXCEPTION_STORE_GPR6
+
+#if 0
+ l.mfspr r6,r0,SPR_ESR_BASE //
+ l.andi r6,r6,SPR_SR_SM // are we in kernel mode ?
+ l.sfeqi r6,0 // r6 == 0x1 --> SM
+ l.bf exit_with_no_itranslation
+ l.nop
+#endif
+
+
+ l.mfspr r4,r0,SPR_EEAR_BASE // get the offending EA
+
+earlyearly:
+ CLEAR_GPR(r6)
+
+ l.srli r3,r4,0xd // r3 <- r4 / 8192 (sets are relative to page size (8Kb) NOT VPN size (4Kb)
+
+ l.mfspr r6, r0, SPR_IMMUCFGR
+ l.andi r6, r6, SPR_IMMUCFGR_NTS
+ l.srli r6, r6, SPR_IMMUCFGR_NTS_OFF
+ l.ori r5, r0, 0x1
+ l.sll r5, r5, r6 // r5 = number IMMU sets from IMMUCFGR
+ l.addi r6, r5, -1 // r6 = nsets mask
+ l.and r2, r3, r6 // r2 <- r3 % NSETS_MASK
+
+ l.or r6,r6,r4 // r6 <- r4
+ l.ori r6,r6,~(VPN_MASK) // r6 <- VPN :VPN .xfff - clear up lo(r6) to 0x**** *fff
+ l.movhi r5,hi(ITLB_MR_MASK) // r5 <- ffff:0000.x000
+ l.ori r5,r5,lo(ITLB_MR_MASK) // r5 <- ffff:1111.x001 - apply ITLB_MR_MASK
+ l.and r5,r5,r6 // r5 <- VPN :VPN .x001 - we have ITLBMR entry
+ l.mtspr r2,r5,SPR_ITLBMR_BASE(0) // set ITLBMR
+
+ /*
+ * set up ITLB with no translation for EA <= 0x0fffffff
+ *
+ * we need this for head.S mapping (EA = PA). if we move all functions
+ * which run with mmu enabled into entry.S, we might be able to eliminate this.
+ *
+ */
+ LOAD_SYMBOL_2_GPR(r6,0x0fffffff)
+ l.sfgeu r6,r4 // flag if r6 >= r4 (if 0xb0ffffff >= EA)
+ l.bf 1f // goto out
+ l.and r3,r4,r4 // delay slot :: 24 <- r4 (if flag==1)
+
+ tophys(r3,r4) // r3 <- PA
+1:
+ l.ori r3,r3,~(PPN_MASK) // r3 <- PPN :PPN .xfff - clear up lo(r6) to 0x**** *fff
+ l.movhi r5,hi(ITLB_TR_MASK) // r5 <- ffff:0000.x000
+ l.ori r5,r5,lo(ITLB_TR_MASK) // r5 <- ffff:1111.x050 - apply ITLB_MR_MASK
+ l.and r5,r5,r3 // r5 <- PPN :PPN .x050 - we have ITLBTR entry
+ l.mtspr r2,r5,SPR_ITLBTR_BASE(0) // set ITLBTR
+
+ EXCEPTION_LOAD_GPR6
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR2
+
+ l.rfe // SR <- ESR, PC <- EPC
+
+exit_with_no_itranslation:
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR6
+ l.j _dispatch_bus_fault
+ l.nop
+
+/* ====================================================================== */
+/*
+ * Stuff below here shouldn't go into .head section... maybe this stuff
+ * can be moved to entry.S ???
+ */
+
+/* ==============================================[ DTLB miss handler ]=== */
+
+/*
+ * Comments:
+ * Exception handlers are entered with MMU off so the following handler
+ * needs to use physical addressing
+ *
+ */
+
+ .text
+ENTRY(dtlb_miss_handler)
+ EXCEPTION_STORE_GPR2
+ EXCEPTION_STORE_GPR3
+ EXCEPTION_STORE_GPR4
+ EXCEPTION_STORE_GPR5
+ EXCEPTION_STORE_GPR6
+ /*
+ * get EA of the miss
+ */
+ l.mfspr r2,r0,SPR_EEAR_BASE
+ /*
+ * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
+ */
+ GET_CURRENT_PGD(r3,r5) // r3 is current_pgd, r5 is temp
+ l.srli r4,r2,0x18 // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
+ l.slli r4,r4,0x2 // to get address << 2
+ l.add r5,r4,r3 // r4 is pgd_index(daddr)
+ /*
+ * if (pmd_none(*pmd))
+ * goto pmd_none:
+ */
+ tophys (r4,r5)
+ l.lwz r3,0x0(r4) // get *pmd value
+ l.sfne r3,r0
+ l.bnf d_pmd_none
+ l.andi r3,r3,~PAGE_MASK //0x1fff // ~PAGE_MASK
+ /*
+ * if (pmd_bad(*pmd))
+ * pmd_clear(pmd)
+ * goto pmd_bad:
+ */
+// l.sfeq r3,r0 // check *pmd value
+// l.bf d_pmd_good
+ l.addi r3,r0,0xffffe000 // PAGE_MASK
+// l.j d_pmd_bad
+// l.sw 0x0(r4),r0 // clear pmd
+d_pmd_good:
+ /*
+ * pte = *pte_offset(pmd, daddr);
+ */
+ l.lwz r4,0x0(r4) // get **pmd value
+ l.and r4,r4,r3 // & PAGE_MASK
+ l.srli r5,r2,0xd // >> PAGE_SHIFT, r2 == EEAR
+ l.andi r3,r5,0x7ff // (1UL << PAGE_SHIFT - 2) - 1
+ l.slli r3,r3,0x2 // to get address << 2
+ l.add r3,r3,r4
+ l.lwz r2,0x0(r3) // this is pte at last
+ /*
+ * if (!pte_present(pte))
+ */
+ l.andi r4,r2,0x1
+ l.sfne r4,r0 // is pte present
+ l.bnf d_pte_not_present
+ l.addi r3,r0,0xffffe3fa // PAGE_MASK | DTLB_UP_CONVERT_MASK
+ /*
+ * fill DTLB TR register
+ */
+ l.and r4,r2,r3 // apply the mask
+ // Determine number of DMMU sets
+ l.mfspr r6, r0, SPR_DMMUCFGR
+ l.andi r6, r6, SPR_DMMUCFGR_NTS
+ l.srli r6, r6, SPR_DMMUCFGR_NTS_OFF
+ l.ori r3, r0, 0x1
+ l.sll r3, r3, r6 // r3 = number DMMU sets DMMUCFGR
+ l.addi r6, r3, -1 // r6 = nsets mask
+ l.and r5, r5, r6 // calc offset: & (NUM_TLB_ENTRIES-1)
+ //NUM_TLB_ENTRIES
+ l.mtspr r5,r4,SPR_DTLBTR_BASE(0)
+ /*
+ * fill DTLB MR register
+ */
+ l.mfspr r2,r0,SPR_EEAR_BASE
+ l.addi r3,r0,0xffffe000 // PAGE_MASK
+ l.and r4,r2,r3 // apply PAGE_MASK to EA (__PHX__ do we really need this?)
+ l.ori r4,r4,0x1 // set hardware valid bit: DTBL_MR entry
+ l.mtspr r5,r4,SPR_DTLBMR_BASE(0)
+
+ EXCEPTION_LOAD_GPR2
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR6
+ l.rfe
+d_pmd_bad:
+ l.nop 1
+ EXCEPTION_LOAD_GPR2
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR6
+ l.rfe
+d_pmd_none:
+d_pte_not_present:
+ EXCEPTION_LOAD_GPR2
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR6
+ l.j _dispatch_do_dpage_fault
+ l.nop
+
+/* ==============================================[ ITLB miss handler ]=== */
+ENTRY(itlb_miss_handler)
+ EXCEPTION_STORE_GPR2
+ EXCEPTION_STORE_GPR3
+ EXCEPTION_STORE_GPR4
+ EXCEPTION_STORE_GPR5
+ EXCEPTION_STORE_GPR6
+ /*
+ * get EA of the miss
+ */
+ l.mfspr r2,r0,SPR_EEAR_BASE
+
+ /*
+ * pmd = (pmd_t *)(current_pgd + pgd_index(daddr));
+ *
+ */
+ GET_CURRENT_PGD(r3,r5) // r3 is current_pgd, r5 is temp
+ l.srli r4,r2,0x18 // >> PAGE_SHIFT + (PAGE_SHIFT - 2)
+ l.slli r4,r4,0x2 // to get address << 2
+ l.add r5,r4,r3 // r4 is pgd_index(daddr)
+ /*
+ * if (pmd_none(*pmd))
+ * goto pmd_none:
+ */
+ tophys (r4,r5)
+ l.lwz r3,0x0(r4) // get *pmd value
+ l.sfne r3,r0
+ l.bnf i_pmd_none
+ l.andi r3,r3,0x1fff // ~PAGE_MASK
+ /*
+ * if (pmd_bad(*pmd))
+ * pmd_clear(pmd)
+ * goto pmd_bad:
+ */
+
+// l.sfeq r3,r0 // check *pmd value
+// l.bf i_pmd_good
+ l.addi r3,r0,0xffffe000 // PAGE_MASK
+// l.j i_pmd_bad
+// l.sw 0x0(r4),r0 // clear pmd
+
+i_pmd_good:
+ /*
+ * pte = *pte_offset(pmd, iaddr);
+ *
+ */
+ l.lwz r4,0x0(r4) // get **pmd value
+ l.and r4,r4,r3 // & PAGE_MASK
+ l.srli r5,r2,0xd // >> PAGE_SHIFT, r2 == EEAR
+ l.andi r3,r5,0x7ff // (1UL << PAGE_SHIFT - 2) - 1
+ l.slli r3,r3,0x2 // to get address << 2
+ l.add r3,r3,r4
+ l.lwz r2,0x0(r3) // this is pte at last
+ /*
+ * if (!pte_present(pte))
+ *
+ */
+ l.andi r4,r2,0x1
+ l.sfne r4,r0 // is pte present
+ l.bnf i_pte_not_present
+ l.addi r3,r0,0xffffe03a // PAGE_MASK | ITLB_UP_CONVERT_MASK
+ /*
+ * fill ITLB TR register
+ */
+ l.and r4,r2,r3 // apply the mask
+ l.andi r3,r2,0x7c0 // _PAGE_EXEC | _PAGE_SRE | _PAGE_SWE | _PAGE_URE | _PAGE_UWE
+// l.andi r3,r2,0x400 // _PAGE_EXEC
+ l.sfeq r3,r0
+ l.bf itlb_tr_fill //_workaround
+ // Determine number of IMMU sets
+ l.mfspr r6, r0, SPR_IMMUCFGR
+ l.andi r6, r6, SPR_IMMUCFGR_NTS
+ l.srli r6, r6, SPR_IMMUCFGR_NTS_OFF
+ l.ori r3, r0, 0x1
+ l.sll r3, r3, r6 // r3 = number IMMU sets IMMUCFGR
+ l.addi r6, r3, -1 // r6 = nsets mask
+ l.and r5, r5, r6 // calc offset: & (NUM_TLB_ENTRIES-1)
+
+/*
+ * __PHX__ :: fixme
+ * we should not just blindly set executable flags,
+ * but it does help with ping. the clean way would be to find out
+ * (and fix it) why stack doesn't have execution permissions
+ */
+
+itlb_tr_fill_workaround:
+ l.ori r4,r4,0xc0 // | (SPR_ITLBTR_UXE | ITLBTR_SXE)
+itlb_tr_fill:
+ l.mtspr r5,r4,SPR_ITLBTR_BASE(0)
+ /*
+ * fill DTLB MR register
+ */
+ l.mfspr r2,r0,SPR_EEAR_BASE
+ l.addi r3,r0,0xffffe000 // PAGE_MASK
+ l.and r4,r2,r3 // apply PAGE_MASK to EA (__PHX__ do we really need this?)
+ l.ori r4,r4,0x1 // set hardware valid bit: DTBL_MR entry
+ l.mtspr r5,r4,SPR_ITLBMR_BASE(0)
+
+ EXCEPTION_LOAD_GPR2
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR6
+ l.rfe
+
+i_pmd_bad:
+ l.nop 1
+ EXCEPTION_LOAD_GPR2
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR6
+ l.rfe
+i_pmd_none:
+i_pte_not_present:
+ EXCEPTION_LOAD_GPR2
+ EXCEPTION_LOAD_GPR3
+ EXCEPTION_LOAD_GPR4
+ EXCEPTION_LOAD_GPR5
+ EXCEPTION_LOAD_GPR6
+ l.j _dispatch_do_ipage_fault
+ l.nop
+
+/* ==============================================[ boot tlb handlers ]=== */
+
+
+/* =================================================[ debugging aids ]=== */
+
+ .align 64
+_immu_trampoline:
+ .space 64
+_immu_trampoline_top:
+
+#define TRAMP_SLOT_0 (0x0)
+#define TRAMP_SLOT_1 (0x4)
+#define TRAMP_SLOT_2 (0x8)
+#define TRAMP_SLOT_3 (0xc)
+#define TRAMP_SLOT_4 (0x10)
+#define TRAMP_SLOT_5 (0x14)
+#define TRAMP_FRAME_SIZE (0x18)
+
+ENTRY(_immu_trampoline_workaround)
+ // r2 EEA
+ // r6 is physical EEA
+ tophys(r6,r2)
+
+ LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
+ tophys (r3,r5) // r3 is trampoline (physical)
+
+ LOAD_SYMBOL_2_GPR(r4,0x15000000)
+ l.sw TRAMP_SLOT_0(r3),r4
+ l.sw TRAMP_SLOT_1(r3),r4
+ l.sw TRAMP_SLOT_4(r3),r4
+ l.sw TRAMP_SLOT_5(r3),r4
+
+ // EPC = EEA - 0x4
+ l.lwz r4,0x0(r6) // load op @ EEA + 0x0 (fc address)
+ l.sw TRAMP_SLOT_3(r3),r4 // store it to _immu_trampoline_data
+ l.lwz r4,-0x4(r6) // load op @ EEA - 0x4 (f8 address)
+ l.sw TRAMP_SLOT_2(r3),r4 // store it to _immu_trampoline_data
+
+ l.srli r5,r4,26 // check opcode for write access
+ l.sfeqi r5,0 // l.j
+ l.bf 0f
+ l.sfeqi r5,0x11 // l.jr
+ l.bf 1f
+ l.sfeqi r5,1 // l.jal
+ l.bf 2f
+ l.sfeqi r5,0x12 // l.jalr
+ l.bf 3f
+ l.sfeqi r5,3 // l.bnf
+ l.bf 4f
+ l.sfeqi r5,4 // l.bf
+ l.bf 5f
+99:
+ l.nop
+ l.j 99b // should never happen
+ l.nop 1
+
+ // r2 is EEA
+ // r3 is trampoline address (physical)
+ // r4 is instruction
+ // r6 is physical(EEA)
+ //
+ // r5
+
+2: // l.jal
+
+ /* 19 20 aa aa l.movhi r9,0xaaaa
+ * a9 29 bb bb l.ori r9,0xbbbb
+ *
+ * where 0xaaaabbbb is EEA + 0x4 shifted right 2
+ */
+
+ l.addi r6,r2,0x4 // this is 0xaaaabbbb
+
+ // l.movhi r9,0xaaaa
+ l.ori r5,r0,0x1920 // 0x1920 == l.movhi r9
+ l.sh (TRAMP_SLOT_0+0x0)(r3),r5
+ l.srli r5,r6,16
+ l.sh (TRAMP_SLOT_0+0x2)(r3),r5
+
+ // l.ori r9,0xbbbb
+ l.ori r5,r0,0xa929 // 0xa929 == l.ori r9
+ l.sh (TRAMP_SLOT_1+0x0)(r3),r5
+ l.andi r5,r6,0xffff
+ l.sh (TRAMP_SLOT_1+0x2)(r3),r5
+
+ /* falthrough, need to set up new jump offset */
+
+
+0: // l.j
+ l.slli r6,r4,6 // original offset shifted left 6 - 2
+// l.srli r6,r6,6 // original offset shifted right 2
+
+ l.slli r4,r2,4 // old jump position: EEA shifted left 4
+// l.srli r4,r4,6 // old jump position: shifted right 2
+
+ l.addi r5,r3,0xc // new jump position (physical)
+ l.slli r5,r5,4 // new jump position: shifted left 4
+
+ // calculate new jump offset
+ // new_off = old_off + (old_jump - new_jump)
+
+ l.sub r5,r4,r5 // old_jump - new_jump
+ l.add r5,r6,r5 // orig_off + (old_jump - new_jump)
+ l.srli r5,r5,6 // new offset shifted right 2
+
+ // r5 is new jump offset
+ // l.j has opcode 0x0...
+ l.sw TRAMP_SLOT_2(r3),r5 // write it back
+
+ l.j trampoline_out
+ l.nop
+
+/* ----------------------------- */
+
+3: // l.jalr
+
+ /* 19 20 aa aa l.movhi r9,0xaaaa
+ * a9 29 bb bb l.ori r9,0xbbbb
+ *
+ * where 0xaaaabbbb is EEA + 0x4 shifted right 2
+ */
+
+ l.addi r6,r2,0x4 // this is 0xaaaabbbb
+
+ // l.movhi r9,0xaaaa
+ l.ori r5,r0,0x1920 // 0x1920 == l.movhi r9
+ l.sh (TRAMP_SLOT_0+0x0)(r3),r5
+ l.srli r5,r6,16
+ l.sh (TRAMP_SLOT_0+0x2)(r3),r5
+
+ // l.ori r9,0xbbbb
+ l.ori r5,r0,0xa929 // 0xa929 == l.ori r9
+ l.sh (TRAMP_SLOT_1+0x0)(r3),r5
+ l.andi r5,r6,0xffff
+ l.sh (TRAMP_SLOT_1+0x2)(r3),r5
+
+ l.lhz r5,(TRAMP_SLOT_2+0x0)(r3) // load hi part of jump instruction
+ l.andi r5,r5,0x3ff // clear out opcode part
+ l.ori r5,r5,0x4400 // opcode changed from l.jalr -> l.jr
+ l.sh (TRAMP_SLOT_2+0x0)(r3),r5 // write it back
+
+ /* falthrough */
+
+1: // l.jr
+ l.j trampoline_out
+ l.nop
+
+/* ----------------------------- */
+
+4: // l.bnf
+5: // l.bf
+ l.slli r6,r4,6 // original offset shifted left 6 - 2
+// l.srli r6,r6,6 // original offset shifted right 2
+
+ l.slli r4,r2,4 // old jump position: EEA shifted left 4
+// l.srli r4,r4,6 // old jump position: shifted right 2
+
+ l.addi r5,r3,0xc // new jump position (physical)
+ l.slli r5,r5,4 // new jump position: shifted left 4
+
+ // calculate new jump offset
+ // new_off = old_off + (old_jump - new_jump)
+
+ l.add r6,r6,r4 // (orig_off + old_jump)
+ l.sub r6,r6,r5 // (orig_off + old_jump) - new_jump
+ l.srli r6,r6,6 // new offset shifted right 2
+
+ // r6 is new jump offset
+ l.lwz r4,(TRAMP_SLOT_2+0x0)(r3) // load jump instruction
+ l.srli r4,r4,16
+ l.andi r4,r4,0xfc00 // get opcode part
+ l.slli r4,r4,16
+ l.or r6,r4,r6 // l.b(n)f new offset
+ l.sw TRAMP_SLOT_2(r3),r6 // write it back
+
+ /* we need to add l.j to EEA + 0x8 */
+ tophys (r4,r2) // may not be needed (due to shifts down_
+ l.addi r4,r4,(0x8 - 0x8) // jump target = r2 + 0x8 (compensate for 0x8)
+ // jump position = r5 + 0x8 (0x8 compensated)
+ l.sub r4,r4,r5 // jump offset = target - new_position + 0x8
+
+ l.slli r4,r4,4 // the amount of info in imediate of jump
+ l.srli r4,r4,6 // jump instruction with offset
+ l.sw TRAMP_SLOT_4(r3),r4 // write it to 4th slot
+
+ /* fallthrough */
+
+trampoline_out:
+ // set up new EPC to point to our trampoline code
+ LOAD_SYMBOL_2_GPR(r5,_immu_trampoline)
+ l.mtspr r0,r5,SPR_EPCR_BASE
+
+ // immu_trampoline is (4x) CACHE_LINE aligned
+ // and only 6 instructions long,
+ // so we need to invalidate only 2 lines
+
+ /* Establish cache block size
+ If BS=0, 16;
+ If BS=1, 32;
+ r14 contain block size
+ */
+ l.mfspr r21,r0,SPR_ICCFGR
+ l.andi r21,r21,SPR_ICCFGR_CBS
+ l.srli r21,r21,7
+ l.ori r23,r0,16
+ l.sll r14,r23,r21
+
+ l.mtspr r0,r5,SPR_ICBIR
+ l.add r5,r5,r14
+ l.mtspr r0,r5,SPR_ICBIR
+
+ l.jr r9
+ l.nop
+
+
+/*
+ * DSCR: prints a string referenced by r3.
+ *
+ * PRMS: r3 - address of the first character of null
+ * terminated string to be printed
+ *
+ * PREQ: UART at UART_BASE_ADD has to be initialized
+ *
+ * POST: caller should be aware that r3, r9 are changed
+ */
+ENTRY(_emergency_print)
+ EMERGENCY_PRINT_STORE_GPR4
+ EMERGENCY_PRINT_STORE_GPR5
+ EMERGENCY_PRINT_STORE_GPR6
+ EMERGENCY_PRINT_STORE_GPR7
+2:
+ l.lbz r7,0(r3)
+ l.sfeq r7,r0
+ l.bf 9f
+ l.nop
+
+// putc:
+ l.movhi r4,hi(UART_BASE_ADD)
+
+ l.addi r6,r0,0x20
+1: l.lbz r5,5(r4)
+ l.andi r5,r5,0x20
+ l.sfeq r5,r6
+ l.bnf 1b
+ l.nop
+
+ l.sb 0(r4),r7
+
+ l.addi r6,r0,0x60
+1: l.lbz r5,5(r4)
+ l.andi r5,r5,0x60
+ l.sfeq r5,r6
+ l.bnf 1b
+ l.nop
+
+ /* next character */
+ l.j 2b
+ l.addi r3,r3,0x1
+
+9:
+ EMERGENCY_PRINT_LOAD_GPR7
+ EMERGENCY_PRINT_LOAD_GPR6
+ EMERGENCY_PRINT_LOAD_GPR5
+ EMERGENCY_PRINT_LOAD_GPR4
+ l.jr r9
+ l.nop
+
+ENTRY(_emergency_print_nr)
+ EMERGENCY_PRINT_STORE_GPR4
+ EMERGENCY_PRINT_STORE_GPR5
+ EMERGENCY_PRINT_STORE_GPR6
+ EMERGENCY_PRINT_STORE_GPR7
+ EMERGENCY_PRINT_STORE_GPR8
+
+ l.addi r8,r0,32 // shift register
+
+1: /* remove leading zeros */
+ l.addi r8,r8,-0x4
+ l.srl r7,r3,r8
+ l.andi r7,r7,0xf
+
+ /* don't skip the last zero if number == 0x0 */
+ l.sfeqi r8,0x4
+ l.bf 2f
+ l.nop
+
+ l.sfeq r7,r0
+ l.bf 1b
+ l.nop
+
+2:
+ l.srl r7,r3,r8
+
+ l.andi r7,r7,0xf
+ l.sflts r8,r0
+ l.bf 9f
+
+ l.sfgtui r7,0x9
+ l.bnf 8f
+ l.nop
+ l.addi r7,r7,0x27
+
+8:
+ l.addi r7,r7,0x30
+// putc:
+ l.movhi r4,hi(UART_BASE_ADD)
+
+ l.addi r6,r0,0x20
+1: l.lbz r5,5(r4)
+ l.andi r5,r5,0x20
+ l.sfeq r5,r6
+ l.bnf 1b
+ l.nop
+
+ l.sb 0(r4),r7
+
+ l.addi r6,r0,0x60
+1: l.lbz r5,5(r4)
+ l.andi r5,r5,0x60
+ l.sfeq r5,r6
+ l.bnf 1b
+ l.nop
+
+ /* next character */
+ l.j 2b
+ l.addi r8,r8,-0x4
+
+9:
+ EMERGENCY_PRINT_LOAD_GPR8
+ EMERGENCY_PRINT_LOAD_GPR7
+ EMERGENCY_PRINT_LOAD_GPR6
+ EMERGENCY_PRINT_LOAD_GPR5
+ EMERGENCY_PRINT_LOAD_GPR4
+ l.jr r9
+ l.nop
+
+
+/*
+ * This should be used for debugging only.
+ * It messes up the Linux early serial output
+ * somehow, so use it sparingly and essentially
+ * only if you need to debug something that goes wrong
+ * before Linux gets the early serial going.
+ *
+ * Furthermore, you'll have to make sure you set the
+ * UART_DEVISOR correctly according to the system
+ * clock rate.
+ *
+ *
+ */
+
+
+
+#define SYS_CLK 20000000
+//#define SYS_CLK 1843200
+#define OR32_CONSOLE_BAUD 115200
+#define UART_DIVISOR SYS_CLK/(16*OR32_CONSOLE_BAUD)
+
+ENTRY(_early_uart_init)
+ l.movhi r3,hi(UART_BASE_ADD)
+
+ l.addi r4,r0,0x7
+ l.sb 0x2(r3),r4
+
+ l.addi r4,r0,0x0
+ l.sb 0x1(r3),r4
+
+ l.addi r4,r0,0x3
+ l.sb 0x3(r3),r4
+
+ l.lbz r5,3(r3)
+ l.ori r4,r5,0x80
+ l.sb 0x3(r3),r4
+ l.addi r4,r0,((UART_DIVISOR>>8) & 0x000000ff)
+ l.sb UART_DLM(r3),r4
+ l.addi r4,r0,((UART_DIVISOR) & 0x000000ff)
+ l.sb UART_DLL(r3),r4
+ l.sb 0x3(r3),r5
+
+ l.jr r9
+ l.nop
+
+_string_copying_linux:
+ .string "\n\n\n\n\n\rCopying Linux... \0"
+
+_string_ok_booting:
+ .string "Ok, booting the kernel.\n\r\0"
+
+_string_unhandled_exception:
+ .string "\n\rRunarunaround: Unhandled exception 0x\0"
+
+_string_epc_prefix:
+ .string ": EPC=0x\0"
+
+_string_nl:
+ .string "\n\r\0"
+
+ .global _string_esr_irq_bug
+_string_esr_irq_bug:
+ .string "\n\rESR external interrupt bug, for details look into entry.S\n\r\0"
+
+
+
+/* ========================================[ page aligned structures ]=== */
+
+/*
+ * .data section should be page aligned
+ * (look into arch/or32/kernel/vmlinux.lds)
+ */
+ .section .data,"aw"
+ .align 8192
+ .global empty_zero_page
+empty_zero_page:
+ .space 8192
+
+ .global swapper_pg_dir
+swapper_pg_dir:
+ .space 8192
+
+ .global _unhandled_stack
+_unhandled_stack:
+ .space 8192
+_unhandled_stack_top:
+
+/* ============================================================[ EOF ]=== */