--- /dev/null
+/*
+ * OpenRISC entry.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) 2005 Gyorgy Jeney <nog@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 <asm/processor.h>
+#include <asm/unistd.h>
+#include <asm/thread_info.h>
+#include <asm/errno.h>
+#include <asm/spr_defs.h>
+#include <asm/page.h>
+#include <asm/mmu.h>
+#include <asm/pgtable.h>
+#include <asm/asm-offsets.h>
+
+#define DISABLE_INTERRUPTS(t1,t2) \
+ l.mfspr t2,r0,SPR_SR ;\
+ l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
+ l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
+ l.and t2,t2,t1 ;\
+ l.mtspr r0,t2,SPR_SR
+
+#define ENABLE_INTERRUPTS(t1) \
+ l.mfspr t1,r0,SPR_SR ;\
+ l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\
+ l.mtspr r0,t1,SPR_SR
+
+/* =========================================================[ macros ]=== */
+
+/*
+ * We need to disable interrupts at beginning of RESTORE_ALL
+ * since interrupt might come in after we've loaded EPC return address
+ * and overwrite EPC with address somewhere in RESTORE_ALL
+ * which is of course wrong!
+ */
+
+#define RESTORE_ALL \
+ DISABLE_INTERRUPTS(r3,r4) ;\
+ l.lwz r3,PT_PC(r1) ;\
+ l.mtspr r0,r3,SPR_EPCR_BASE ;\
+ l.lwz r3,PT_SR(r1) ;\
+ l.mtspr r0,r3,SPR_ESR_BASE ;\
+ l.lwz r2,PT_GPR2(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.lwz r8,PT_GPR8(r1) ;\
+ l.lwz r9,PT_GPR9(r1) ;\
+ l.lwz r10,PT_GPR10(r1) ;\
+ l.lwz r11,PT_GPR11(r1) ;\
+ l.lwz r12,PT_GPR12(r1) ;\
+ l.lwz r13,PT_GPR13(r1) ;\
+ l.lwz r14,PT_GPR14(r1) ;\
+ l.lwz r15,PT_GPR15(r1) ;\
+ l.lwz r16,PT_GPR16(r1) ;\
+ l.lwz r17,PT_GPR17(r1) ;\
+ l.lwz r18,PT_GPR18(r1) ;\
+ l.lwz r19,PT_GPR19(r1) ;\
+ l.lwz r20,PT_GPR20(r1) ;\
+ l.lwz r21,PT_GPR21(r1) ;\
+ l.lwz r22,PT_GPR22(r1) ;\
+ l.lwz r23,PT_GPR23(r1) ;\
+ l.lwz r24,PT_GPR24(r1) ;\
+ l.lwz r25,PT_GPR25(r1) ;\
+ l.lwz r26,PT_GPR26(r1) ;\
+ l.lwz r27,PT_GPR27(r1) ;\
+ l.lwz r28,PT_GPR28(r1) ;\
+ l.lwz r29,PT_GPR29(r1) ;\
+ l.lwz r30,PT_GPR30(r1) ;\
+ l.lwz r31,PT_GPR31(r1) ;\
+ l.lwz r1,PT_SP(r1) ;\
+ l.rfe
+
+
+#define EXCEPTION_ENTRY(handler) \
+ .global handler ;\
+handler: ;\
+ /* r1, EPCR, ESR a already saved */ ;\
+ l.sw PT_GPR2(r1),r2 ;\
+ l.sw PT_GPR3(r1),r3 ;\
+ l.sw PT_ORIG_GPR11(r1),r11 ;\
+ /* r4 already save */ ;\
+ 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 ;\
+ /* r12 already saved */ ;\
+ l.sw PT_GPR13(r1),r13 ;\
+ l.sw PT_GPR14(r1),r14 ;\
+ l.sw PT_GPR15(r1),r15 ;\
+ l.sw PT_GPR16(r1),r16 ;\
+ l.sw PT_GPR17(r1),r17 ;\
+ l.sw PT_GPR18(r1),r18 ;\
+ l.sw PT_GPR19(r1),r19 ;\
+ l.sw PT_GPR20(r1),r20 ;\
+ l.sw PT_GPR21(r1),r21 ;\
+ l.sw PT_GPR22(r1),r22 ;\
+ l.sw PT_GPR23(r1),r23 ;\
+ l.sw PT_GPR24(r1),r24 ;\
+ l.sw PT_GPR25(r1),r25 ;\
+ l.sw PT_GPR26(r1),r26 ;\
+ l.sw PT_GPR27(r1),r27 ;\
+ l.sw PT_GPR28(r1),r28 ;\
+ l.sw PT_GPR29(r1),r29 ;\
+ /* r30 already save */ ;\
+/* l.sw PT_GPR30(r1),r30*/ ;\
+ l.sw PT_GPR31(r1),r31 ;\
+ l.sw PT_SYSCALLNO(r1),r0
+
+#define UNHANDLED_EXCEPTION(handler,vector) \
+ .global handler ;\
+handler: ;\
+ /* r1, EPCR, ESR already saved */ ;\
+ l.sw PT_GPR2(r1),r2 ;\
+ l.sw PT_GPR3(r1),r3 ;\
+ l.sw PT_ORIG_GPR11(r1),r11 ;\
+ 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 ;\
+ /* r12 already saved */ ;\
+ l.sw PT_GPR13(r1),r13 ;\
+ l.sw PT_GPR14(r1),r14 ;\
+ l.sw PT_GPR15(r1),r15 ;\
+ l.sw PT_GPR16(r1),r16 ;\
+ l.sw PT_GPR17(r1),r17 ;\
+ l.sw PT_GPR18(r1),r18 ;\
+ l.sw PT_GPR19(r1),r19 ;\
+ l.sw PT_GPR20(r1),r20 ;\
+ l.sw PT_GPR21(r1),r21 ;\
+ l.sw PT_GPR22(r1),r22 ;\
+ l.sw PT_GPR23(r1),r23 ;\
+ l.sw PT_GPR24(r1),r24 ;\
+ l.sw PT_GPR25(r1),r25 ;\
+ l.sw PT_GPR26(r1),r26 ;\
+ l.sw PT_GPR27(r1),r27 ;\
+ l.sw PT_GPR28(r1),r28 ;\
+ l.sw PT_GPR29(r1),r29 ;\
+ /* r31 already saved */ ;\
+ l.sw PT_GPR30(r1),r30 ;\
+/* l.sw PT_GPR31(r1),r31 */ ;\
+ l.sw PT_SYSCALLNO(r1),r0 ;\
+ l.addi r3,r1,0 ;\
+ /* r4 is exception EA */ ;\
+ l.addi r5,r0,vector ;\
+ l.jal unhandled_exception ;\
+ l.nop ;\
+ l.j _ret_from_exception ;\
+ l.nop
+
+/*
+ * NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR
+ * contain the same values as when exception we're handling
+ * occured. in fact they never do. if you need them use
+ * values saved on stack (for SPR_EPC, SPR_ESR) or content
+ * of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE()
+ * in 'arch/or32/kernel/head.S'
+ */
+
+/* =====================================================[ exceptions] === */
+
+/* ---[ 0x100: RESET exception ]----------------------------------------- */
+
+EXCEPTION_ENTRY(_tng_kernel_start)
+ l.jal _start
+ l.andi r0,r0,0
+
+/* ---[ 0x200: BUS exception ]------------------------------------------- */
+
+EXCEPTION_ENTRY(_bus_fault_handler)
+ /* r4: EA of fault (set by EXCEPTION_HANDLE) */
+ l.jal do_bus_fault
+ l.addi r3,r1,0 /* pt_regs */
+
+ l.j _ret_from_exception
+ l.nop
+
+/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
+
+EXCEPTION_ENTRY(_data_page_fault_handler)
+ /* set up parameters for do_page_fault */
+ l.addi r3,r1,0 // pt_regs
+ /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
+ l.ori r5,r0,0x300 // exception vector
+
+ /*
+ * __PHX__: TODO
+ *
+ * all this can be written much simpler. look at
+ * DTLB miss handler in the CONFIG_GUARD_PROTECTED_CORE part
+ */
+#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
+ l.lwz r6,PT_PC(r3) // address of an offending insn
+ l.lwz r6,0(r6) // instruction that caused pf
+
+ l.srli r6,r6,26 // check opcode for jump insn
+ l.sfeqi r6,0 // l.j
+ l.bf 8f
+ l.sfeqi r6,1 // l.jal
+ l.bf 8f
+ l.sfeqi r6,3 // l.bnf
+ l.bf 8f
+ l.sfeqi r6,4 // l.bf
+ l.bf 8f
+ l.sfeqi r6,0x11 // l.jr
+ l.bf 8f
+ l.sfeqi r6,0x12 // l.jalr
+ l.bf 8f
+
+ l.nop
+
+ l.j 9f
+ l.nop
+8:
+
+ l.lwz r6,PT_PC(r3) // address of an offending insn
+ l.addi r6,r6,4
+ l.lwz r6,0(r6) // instruction that caused pf
+ l.srli r6,r6,26 // get opcode
+9:
+
+#else
+
+ l.mfspr r6,r0,SPR_SR // SR
+// l.lwz r6,PT_SR(r3) // ESR
+ l.andi r6,r6,SPR_SR_DSX // check for delay slot exception
+ l.sfeqi r6,0x1 // exception happened in delay slot
+ l.bnf 7f
+ l.lwz r6,PT_PC(r3) // address of an offending insn
+
+ l.addi r6,r6,4 // offending insn is in delay slot
+7:
+ l.lwz r6,0(r6) // instruction that caused pf
+ l.srli r6,r6,26 // check opcode for write access
+#endif
+
+ l.sfgeui r6,0x34 // check opcode for write access
+ l.bnf 1f
+ l.sfleui r6,0x37
+ l.bnf 1f
+ l.ori r6,r0,0x1 // write access
+ l.j 2f
+ l.nop
+1: l.ori r6,r0,0x0 // !write access
+2:
+
+ /* call fault.c handler in or32/mm/fault.c */
+ l.jal do_page_fault
+ l.nop
+ l.j _ret_from_exception
+ l.nop
+
+/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
+
+EXCEPTION_ENTRY(_insn_page_fault_handler)
+ /* set up parameters for do_page_fault */
+ l.addi r3,r1,0 // pt_regs
+ /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
+ l.ori r5,r0,0x400 // exception vector
+ l.ori r6,r0,0x0 // !write access
+
+ /* call fault.c handler in or32/mm/fault.c */
+ l.jal do_page_fault
+ l.nop
+ l.j _ret_from_exception
+ l.nop
+
+
+/* ---[ 0x500: Timer exception ]----------------------------------------- */
+
+EXCEPTION_ENTRY(_timer_handler)
+ l.jal timer_interrupt
+ l.addi r3,r1,0 /* pt_regs */
+
+ l.j _ret_from_intr
+ l.nop
+
+/* ---[ 0x600: Aligment exception ]-------------------------------------- */
+
+EXCEPTION_ENTRY(_alignment_handler)
+ /* r4: EA of fault (set by EXCEPTION_HANDLE) */
+ l.jal do_unaligned_access
+ l.addi r3,r1,0 /* pt_regs */
+
+ l.j _ret_from_exception
+ l.nop
+
+#if 0
+EXCEPTION_ENTRY(_aligment_handler)
+// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the efective addres */
+ l.addi r2,r4,0
+// l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */
+ l.lwz r5,PT_PC(r1)
+
+ l.lwz r3,0(r5) /* Load insn */
+ l.srli r4,r3,26 /* Shift left to get the insn opcode */
+
+ l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */
+ l.bf jmp
+ l.sfeqi r4,0x01
+ l.bf jmp
+ l.sfeqi r4,0x03
+ l.bf jmp
+ l.sfeqi r4,0x04
+ l.bf jmp
+ l.sfeqi r4,0x11
+ l.bf jr
+ l.sfeqi r4,0x12
+ l.bf jr
+ l.nop
+ l.j 1f
+ l.addi r5,r5,4 /* Increment PC to get return insn address */
+
+jmp:
+ l.slli r4,r3,6 /* Get the signed extended jump length */
+ l.srai r4,r4,4
+
+ l.lwz r3,4(r5) /* Load the real load/store insn */
+
+ l.add r5,r5,r4 /* Calculate jump target address */
+
+ l.j 1f
+ l.srli r4,r3,26 /* Shift left to get the insn opcode */
+
+jr:
+ l.slli r4,r3,9 /* Shift to get the reg nb */
+ l.andi r4,r4,0x7c
+
+ l.lwz r3,4(r5) /* Load the real load/store insn */
+
+ l.add r4,r4,r1 /* Load the jump register value from the stack */
+ l.lwz r5,0(r4)
+
+ l.srli r4,r3,26 /* Shift left to get the insn opcode */
+
+
+1:
+// l.mtspr r0,r5,SPR_EPCR_BASE
+ l.sw PT_PC(r1),r5
+
+ l.sfeqi r4,0x26
+ l.bf lhs
+ l.sfeqi r4,0x25
+ l.bf lhz
+ l.sfeqi r4,0x22
+ l.bf lws
+ l.sfeqi r4,0x21
+ l.bf lwz
+ l.sfeqi r4,0x37
+ l.bf sh
+ l.sfeqi r4,0x35
+ l.bf sw
+ l.nop
+
+1: l.j 1b /* I don't know what to do */
+ l.nop
+
+lhs: l.lbs r5,0(r2)
+ l.slli r5,r5,8
+ l.lbz r6,1(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
+
+lhz: l.lbz r5,0(r2)
+ l.slli r5,r5,8
+ l.lbz r6,1(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
+
+lws: l.lbs 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
+
+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
+ 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 */
+ /* This is used by do_signal to determine whether to check for
+ * syscall restart or not */
+ l.sw PT_SYSCALLNO(r1),r11
+
+_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_SYSCALLNO(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
+
+ /* _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
+
+/* Since syscalls don't save call-clobbered registers, the args to
+ * kernel_thread_helper will need to be passed through callee-saved
+ * registers and copied to the parameter registers when the thread
+ * begins running.
+ *
+ * See arch/openrisc/kernel/process.c:
+ * The args are passed as follows:
+ * arg1 (r3) : passed in r20
+ * arg2 (r4) : passed in r22
+ */
+
+ENTRY(_kernel_thread_helper)
+ l.or r3,r20,r0
+ l.or r4,r22,r0
+ l.movhi r31,hi(kernel_thread_helper)
+ l.ori r31,r31,lo(kernel_thread_helper)
+ l.jr r31
+ 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 can be
+ * either schedule() or return_from_fork()... */
+ 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_execve)
+ l.j _sys_execve
+ l.addi r6,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 r30,0(r4)
+ l.lwz r28,0(r5)
+ l.sw 0(r4),r28
+ l.sw 0(r5),r30
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r0,r0
+
+/* ============================================================[ EOF ]=== */
--- /dev/null
+/*
+ * 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 ]=== */
--- /dev/null
+/*
+ * OpenRISC setup.c
+ *
+ * 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.
+ *
+ * This file handles the architecture-dependent parts of initialization
+ */
+
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/bootmem.h>
+#include <linux/seq_file.h>
+#include <linux/serial.h>
+#include <linux/initrd.h>
+#include <linux/of_fdt.h>
+#include <linux/of.h>
+#include <linux/memblock.h>
+#include <linux/device.h>
+#include <linux/of_platform.h>
+
+#include <asm/segment.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/types.h>
+#include <asm/setup.h>
+#include <asm/io.h>
+#include <asm/cpuinfo.h>
+#include <asm/delay.h>
+
+#include "vmlinux.h"
+
+char __initdata cmd_line[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
+
+static unsigned long __init setup_memory(void)
+{
+ unsigned long bootmap_size;
+ unsigned long ram_start_pfn;
+ unsigned long free_ram_start_pfn;
+ unsigned long ram_end_pfn;
+ phys_addr_t memory_start, memory_end;
+ struct memblock_region *region;
+
+ memory_end = memory_start = 0;
+
+ /* Find main memory where is the kernel */
+ for_each_memblock(memory, region) {
+ memory_start = region->base;
+ memory_end = region->base + region->size;
+ printk(KERN_INFO "%s: Memory: 0x%x-0x%x\n", __func__,
+ memory_start, memory_end);
+ }
+
+ if (!memory_end) {
+ panic("No memory!");
+ }
+
+ ram_start_pfn = PFN_UP(memory_start);
+ /* free_ram_start_pfn is first page after kernel */
+ free_ram_start_pfn = PFN_UP(__pa(&_end));
+ ram_end_pfn = PFN_DOWN(memblock_end_of_DRAM());
+
+ max_pfn = ram_end_pfn;
+
+ /*
+ * initialize the boot-time allocator (with low memory only).
+ *
+ * This makes the memory from the end of the kernel to the end of
+ * RAM usable.
+ * init_bootmem sets the global values min_low_pfn, max_low_pfn.
+ */
+ bootmap_size = init_bootmem(free_ram_start_pfn,
+ ram_end_pfn - ram_start_pfn);
+ free_bootmem(PFN_PHYS(free_ram_start_pfn),
+ (ram_end_pfn - free_ram_start_pfn) << PAGE_SHIFT);
+ reserve_bootmem(PFN_PHYS(free_ram_start_pfn), bootmap_size,
+ BOOTMEM_DEFAULT);
+
+ for_each_memblock(reserved, region) {
+ printk(KERN_INFO "Reserved - 0x%08x-0x%08x\n",
+ (u32) region->base, (u32) region->size);
+ reserve_bootmem(region->base, region->size, BOOTMEM_DEFAULT);
+ }
+
+ return ram_end_pfn;
+}
+
+struct cpuinfo cpuinfo;
+
+static void print_cpuinfo(void)
+{
+ unsigned long upr = mfspr(SPR_UPR);
+ unsigned long vr = mfspr(SPR_VR);
+ unsigned int version;
+ unsigned int revision;
+
+ version = (vr & SPR_VR_VER) >> 24;
+ revision = (vr & SPR_VR_REV);
+
+ printk(KERN_INFO "CPU: OpenRISC-%x (revision %d) @%d MHz\n",
+ version, revision, cpuinfo.clock_frequency / 1000000);
+
+ if (!(upr & SPR_UPR_UP)) {
+ printk(KERN_INFO
+ "-- no UPR register... unable to detect configuration\n");
+ return;
+ }
+
+ if (upr & SPR_UPR_DCP)
+ printk(KERN_INFO
+ "-- dcache: %4d bytes total, %2d bytes/line, %d way(s)\n",
+ cpuinfo.dcache_size, cpuinfo.dcache_block_size, 1);
+ else
+ printk(KERN_INFO "-- dcache disabled\n");
+ if (upr & SPR_UPR_ICP)
+ printk(KERN_INFO
+ "-- icache: %4d bytes total, %2d bytes/line, %d way(s)\n",
+ cpuinfo.icache_size, cpuinfo.icache_block_size, 1);
+ else
+ printk(KERN_INFO "-- icache disabled\n");
+
+ if (upr & SPR_UPR_DMP)
+ printk(KERN_INFO "-- dmmu: %4d entries, %lu way(s)\n",
+ 1 << ((mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_NTS) >> 2),
+ 1 + (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_NTW));
+ if (upr & SPR_UPR_IMP)
+ printk(KERN_INFO "-- immu: %4d entries, %lu way(s)\n",
+ 1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> 2),
+ 1 + (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTW));
+
+ printk(KERN_INFO "-- additional features:\n");
+ if (upr & SPR_UPR_DUP)
+ printk(KERN_INFO "-- debug unit\n");
+ if (upr & SPR_UPR_PCUP)
+ printk(KERN_INFO "-- performance counters\n");
+ if (upr & SPR_UPR_PMP)
+ printk(KERN_INFO "-- power management\n");
+ if (upr & SPR_UPR_PICP)
+ printk(KERN_INFO "-- PIC\n");
+ if (upr & SPR_UPR_TTP)
+ printk(KERN_INFO "-- timer\n");
+ if (upr & SPR_UPR_CUP)
+ printk(KERN_INFO "-- custom unit(s)\n");
+}
+
+void __init setup_cpuinfo(void)
+{
+ struct device_node *cpu;
+ unsigned long iccfgr, dccfgr;
+ unsigned long cache_set_size, cache_ways;
+
+ cpu = of_find_compatible_node(NULL, NULL, "opencores,or1200-rtlsvn481");
+ if (!cpu)
+ panic("No compatible CPU found in device tree...\n");
+
+ iccfgr = mfspr(SPR_ICCFGR);
+ cache_ways = 1 << (iccfgr & SPR_ICCFGR_NCW);
+ cache_set_size = 1 << ((iccfgr & SPR_ICCFGR_NCS) >> 3);
+ cpuinfo.icache_block_size = 16 << ((iccfgr & SPR_ICCFGR_CBS) >> 7);
+ cpuinfo.icache_size =
+ cache_set_size * cache_ways * cpuinfo.icache_block_size;
+
+ dccfgr = mfspr(SPR_DCCFGR);
+ cache_ways = 1 << (dccfgr & SPR_DCCFGR_NCW);
+ cache_set_size = 1 << ((dccfgr & SPR_DCCFGR_NCS) >> 3);
+ cpuinfo.dcache_block_size = 16 << ((dccfgr & SPR_DCCFGR_CBS) >> 7);
+ cpuinfo.dcache_size =
+ cache_set_size * cache_ways * cpuinfo.dcache_block_size;
+
+ if (of_property_read_u32(cpu, "clock-frequency",
+ &cpuinfo.clock_frequency)) {
+ printk(KERN_WARNING
+ "Device tree missing CPU 'clock-frequency' parameter."
+ "Assuming frequency 25MHZ"
+ "This is probably not what you want.");
+ }
+
+ of_node_put(cpu);
+
+ print_cpuinfo();
+}
+
+/**
+ * or32_early_setup
+ *
+ * Handles the pointer to the device tree that this kernel is to use
+ * for establishing the available platform devices.
+ *
+ * For now, this is limited to using the built-in device tree. In the future,
+ * it is intended that this function will take a pointer to the device tree
+ * that is potentially built-in, but potentially also passed in by the
+ * bootloader, or discovered by some equally clever means...
+ */
+
+void __init or32_early_setup(void)
+{
+
+ early_init_devtree(__dtb_start);
+
+ printk(KERN_INFO "Compiled-in FDT at 0x%p\n", __dtb_start);
+}
+
+static int __init openrisc_device_probe(void)
+{
+ of_platform_populate(NULL, NULL, NULL, NULL);
+
+ return 0;
+}
+
+device_initcall(openrisc_device_probe);
+
+static inline unsigned long extract_value_bits(unsigned long reg,
+ short bit_nr, short width)
+{
+ return (reg >> bit_nr) & (0 << width);
+}
+
+static inline unsigned long extract_value(unsigned long reg, unsigned long mask)
+{
+ while (!(mask & 0x1)) {
+ reg = reg >> 1;
+ mask = mask >> 1;
+ }
+ return mask & reg;
+}
+
+void __init detect_unit_config(unsigned long upr, unsigned long mask,
+ char *text, void (*func) (void))
+{
+ if (text != NULL)
+ printk("%s", text);
+
+ if (upr & mask) {
+ if (func != NULL)
+ func();
+ else
+ printk("present\n");
+ } else
+ printk("not present\n");
+}
+
+/*
+ * calibrate_delay
+ *
+ * Lightweight calibrate_delay implementation that calculates loops_per_jiffy
+ * from the clock frequency passed in via the device tree
+ *
+ */
+
+void __cpuinit calibrate_delay(void)
+{
+ const int *val;
+ struct device_node *cpu = NULL;
+ cpu = of_find_compatible_node(NULL, NULL, "opencores,or1200-rtlsvn481");
+ val = of_get_property(cpu, "clock-frequency", NULL);
+ if (!val)
+ panic("no cpu 'clock-frequency' parameter in device tree");
+ loops_per_jiffy = *val / HZ;
+ pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n",
+ loops_per_jiffy / (500000 / HZ),
+ (loops_per_jiffy / (5000 / HZ)) % 100, loops_per_jiffy);
+}
+
+void __init setup_arch(char **cmdline_p)
+{
+ unsigned long max_low_pfn;
+
+ unflatten_device_tree();
+
+ setup_cpuinfo();
+
+ /* process 1's initial memory region is the kernel code/data */
+ init_mm.start_code = (unsigned long)&_stext;
+ init_mm.end_code = (unsigned long)&_etext;
+ init_mm.end_data = (unsigned long)&_edata;
+ init_mm.brk = (unsigned long)&_end;
+
+#ifdef CONFIG_BLK_DEV_INITRD
+ initrd_start = (unsigned long)&__initrd_start;
+ initrd_end = (unsigned long)&__initrd_end;
+ if (initrd_start == initrd_end) {
+ initrd_start = 0;
+ initrd_end = 0;
+ }
+ initrd_below_start_ok = 1;
+#endif
+
+ /* setup bootmem allocator */
+ max_low_pfn = setup_memory();
+
+ /* paging_init() sets up the MMU and marks all pages as reserved */
+ paging_init();
+
+#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
+ if (!conswitchp)
+ conswitchp = &dummy_con;
+#endif
+
+ *cmdline_p = cmd_line;
+
+ printk(KERN_INFO "OpenRISC Linux -- http://openrisc.net\n");
+}
+
+static int show_cpuinfo(struct seq_file *m, void *v)
+{
+ unsigned long vr;
+ int version, revision;
+
+ vr = mfspr(SPR_VR);
+ version = (vr & SPR_VR_VER) >> 24;
+ revision = vr & SPR_VR_REV;
+
+ return seq_printf(m,
+ "cpu\t\t: OpenRISC-%x\n"
+ "revision\t: %d\n"
+ "frequency\t: %ld\n"
+ "dcache size\t: %d bytes\n"
+ "dcache block size\t: %d bytes\n"
+ "icache size\t: %d bytes\n"
+ "icache block size\t: %d bytes\n"
+ "immu\t\t: %d entries, %lu ways\n"
+ "dmmu\t\t: %d entries, %lu ways\n"
+ "bogomips\t: %lu.%02lu\n",
+ version,
+ revision,
+ loops_per_jiffy * HZ,
+ cpuinfo.dcache_size,
+ cpuinfo.dcache_block_size,
+ cpuinfo.icache_size,
+ cpuinfo.icache_block_size,
+ 1 << ((mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_NTS) >> 2),
+ 1 + (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_NTW),
+ 1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> 2),
+ 1 + (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTW),
+ (loops_per_jiffy * HZ) / 500000,
+ ((loops_per_jiffy * HZ) / 5000) % 100);
+}
+
+static void *c_start(struct seq_file *m, loff_t * pos)
+{
+ /* We only have one CPU... */
+ return *pos < 1 ? (void *)1 : NULL;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t * pos)
+{
+ ++*pos;
+ return NULL;
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+const struct seq_operations cpuinfo_op = {
+ .start = c_start,
+ .next = c_next,
+ .stop = c_stop,
+ .show = show_cpuinfo,
+};
projects / linux-beck.git / commitdiff