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+/*
+ * 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 ]=== */
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * Trace irq on/off creating a stack frame.
+ */
+#define TRACE_IRQS_OP(trace_op) \
+ l.sw -8(r1),r2 /* store frame pointer */ ;\
+ l.sw -4(r1),r9 /* store return address */ ;\
+ l.addi r2,r1,0 /* move sp to fp */ ;\
+ l.jal trace_op ;\
+ l.addi r1,r1,-8 ;\
+ l.ori r1,r2,0 /* restore sp */ ;\
+ l.lwz r9,-4(r1) /* restore return address */ ;\
+ l.lwz r2,-8(r1) /* restore fp */ ;\
+/*
+ * Trace irq on/off and save registers we need that would otherwise be
+ * clobbered.
+ */
+#define TRACE_IRQS_SAVE(t1,trace_op) \
+ l.sw -12(r1),t1 /* save extra reg */ ;\
+ l.sw -8(r1),r2 /* store frame pointer */ ;\
+ l.sw -4(r1),r9 /* store return address */ ;\
+ l.addi r2,r1,0 /* move sp to fp */ ;\
+ l.jal trace_op ;\
+ l.addi r1,r1,-12 ;\
+ l.ori r1,r2,0 /* restore sp */ ;\
+ l.lwz r9,-4(r1) /* restore return address */ ;\
+ l.lwz r2,-8(r1) /* restore fp */ ;\
+ l.lwz t1,-12(r1) /* restore extra reg */
+
+#define TRACE_IRQS_OFF TRACE_IRQS_OP(trace_hardirqs_off)
+#define TRACE_IRQS_ON TRACE_IRQS_OP(trace_hardirqs_on)
+#define TRACE_IRQS_ON_SYSCALL \
+ TRACE_IRQS_SAVE(r10,trace_hardirqs_on) ;\
+ 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 r11,PT_GPR11(r1)
+#define TRACE_IRQS_OFF_ENTRY \
+ l.lwz r5,PT_SR(r1) ;\
+ l.andi r3,r5,(SPR_SR_IEE|SPR_SR_TEE) ;\
+ l.sfeq r5,r0 /* skip trace if irqs were already off */;\
+ l.bf 1f ;\
+ l.nop ;\
+ TRACE_IRQS_SAVE(r4,trace_hardirqs_off) ;\
+1:
+#else
+#define TRACE_IRQS_OFF
+#define TRACE_IRQS_ON
+#define TRACE_IRQS_OFF_ENTRY
+#define TRACE_IRQS_ON_SYSCALL
+#endif
+
+/*
+ * 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 ;\
+ /* 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 ;\
+ TRACE_IRQS_OFF_ENTRY ;\
+ /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
+ l.addi r30,r0,-1 ;\
+ l.sw PT_ORIG_GPR11(r1),r30
+
+#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_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 */ ;\
+ /* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
+ l.addi r30,r0,-1 ;\
+ l.sw PT_ORIG_GPR11(r1),r30 ;\
+ 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
+
+/* clobbers 'reg' */
+#define CLEAR_LWA_FLAG(reg) \
+ l.movhi reg,hi(lwa_flag) ;\
+ l.ori reg,reg,lo(lwa_flag) ;\
+ l.sw 0(reg),r0
+/*
+ * 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/openrisc/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)
+ CLEAR_LWA_FLAG(r3)
+ /* 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(_dtlb_miss_page_fault_handler)
+ CLEAR_LWA_FLAG(r3)
+ l.and r5,r5,r0
+ l.j 1f
+ l.nop
+
+EXCEPTION_ENTRY(_data_page_fault_handler)
+ CLEAR_LWA_FLAG(r3)
+ /* set up parameters for do_page_fault */
+ l.ori r5,r0,0x300 // exception vector
+1:
+ l.addi r3,r1,0 // pt_regs
+ /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
+
+#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: // offending insn is in delay slot
+ 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: // offending instruction opcode loaded in r6
+
+#else
+
+ l.mfspr r6,r0,SPR_SR // SR
+ l.andi r6,r6,SPR_SR_DSX // check for delay slot exception
+ l.sfne r6,r0 // 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 r6,0x33 // 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(_itlb_miss_page_fault_handler)
+ CLEAR_LWA_FLAG(r3)
+ l.and r5,r5,r0
+ l.j 1f
+ l.nop
+
+EXCEPTION_ENTRY(_insn_page_fault_handler)
+ CLEAR_LWA_FLAG(r3)
+ /* set up parameters for do_page_fault */
+ l.ori r5,r0,0x400 // exception vector
+1:
+ l.addi r3,r1,0 // pt_regs
+ /* r4 set be EXCEPTION_HANDLE */ // effective address of fault
+ 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)
+ CLEAR_LWA_FLAG(r3)
+ l.jal timer_interrupt
+ l.addi r3,r1,0 /* pt_regs */
+
+ l.j _ret_from_intr
+ l.nop
+
+/* ---[ 0x600: Alignment exception ]-------------------------------------- */
+
+EXCEPTION_ENTRY(_alignment_handler)
+ CLEAR_LWA_FLAG(r3)
+ /* 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(_alignment_handler)
+// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the effective address */
+ 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
+
+#ifdef CONFIG_PRINTK
+ 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
+#endif
+
+ l.ori r4,r4,SPR_SR_IEE // fix the bug
+// l.sw PT_SR(r1),r4
+1:
+#endif
+ CLEAR_LWA_FLAG(r3)
+ 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)
+ /* 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, use it as screatch reg and
+ * then load the original r4
+ */
+ CLEAR_LWA_FLAG(r4)
+ l.lwz r4,PT_GPR4(r1)
+ l.sw PT_GPR5(r1),r5
+ l.sw PT_GPR6(r1),r6
+ l.sw PT_GPR7(r1),r7
+ l.sw PT_GPR8(r1),r8
+ l.sw PT_GPR9(r1),r9
+ /* r10 already saved */
+ l.sw PT_GPR11(r1),r11
+ /* orig_gpr11 must be set for syscalls */
+ l.sw PT_ORIG_GPR11(r1),r11
+ /* r12,r13 already saved */
+
+ /* r14-r28 (even) aren't touched by the syscall fast path below
+ * so we don't need to save them. However, the functions that return
+ * to userspace via a call to switch() DO need to save these because
+ * switch() effectively clobbers them... saving these registers for
+ * such functions is handled in their syscall wrappers (see fork, vfork,
+ * and clone, below).
+
+ /* r30 is the only register we clobber in the fast path */
+ /* r30 already saved */
+/* l.sw PT_GPR30(r1),r30 */
+
+_syscall_check_trace_enter:
+ /* syscalls run with interrupts enabled */
+ TRACE_IRQS_ON_SYSCALL
+ ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
+
+ /* 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)
+ TRACE_IRQS_OFF
+ l.lwz r30,TI_FLAGS(r10)
+ l.andi r30,r30,_TIF_WORK_MASK
+ l.sfne r30,r0
+
+ l.bnf _syscall_resume_userspace
+ l.nop
+
+ /* Work pending follows a different return path, so we need to
+ * make sure that all the call-saved registers get into pt_regs
+ * before branching...
+ */
+ l.sw PT_GPR14(r1),r14
+ l.sw PT_GPR16(r1),r16
+ l.sw PT_GPR18(r1),r18
+ l.sw PT_GPR20(r1),r20
+ l.sw PT_GPR22(r1),r22
+ l.sw PT_GPR24(r1),r24
+ l.sw PT_GPR26(r1),r26
+ l.sw PT_GPR28(r1),r28
+
+ /* _work_pending needs to be called with interrupts disabled */
+ l.j _work_pending
+ l.nop
+
+_syscall_resume_userspace:
+// ENABLE_INTERRUPTS(r29)
+
+
+/* This is the hot path for returning to userspace from a syscall. If there's
+ * work to be done and the branch to _work_pending was taken above, then the
+ * return to userspace will be done via the normal exception return path...
+ * that path restores _all_ registers and will overwrite the "clobbered"
+ * registers with whatever garbage is in pt_regs -- that's OK because those
+ * registers are clobbered anyway and because the extra work is insignificant
+ * in the context of the extra work that _work_pending is doing.
+
+/* Once again, syscalls are special and only guarantee to preserve the
+ * same registers as a normal function call */
+
+/* The assumption here is that the registers r14-r28 (even) are untouched and
+ * don't need to be restored... be sure that that's really the case!
+ */
+
+/* This is still too much... we should only be restoring what we actually
+ * clobbered... we should even be using 'scratch' (odd) regs above so that
+ * we don't need to restore anything, hardly...
+ */
+
+ l.lwz r2,PT_GPR2(r1)
+
+ /* Restore args */
+ /* r3-r8 are technically clobbered, but syscall restart needs these
+ * to be restored...
+ */
+ l.lwz r3,PT_GPR3(r1)
+ l.lwz r4,PT_GPR4(r1)
+ l.lwz r5,PT_GPR5(r1)
+ l.lwz r6,PT_GPR6(r1)
+ l.lwz r7,PT_GPR7(r1)
+ l.lwz r8,PT_GPR8(r1)
+
+ l.lwz r9,PT_GPR9(r1)
+ l.lwz r10,PT_GPR10(r1)
+ l.lwz r11,PT_GPR11(r1)
+
+ /* r30 is the only register we clobber in the fast path */
+ l.lwz r30,PT_GPR30(r1)
+
+ /* Here we use r13-r19 (odd) as scratch regs */
+ l.lwz r13,PT_PC(r1)
+ l.lwz r15,PT_SR(r1)
+ l.lwz r1,PT_SP(r1)
+ /* Interrupts need to be disabled for setting EPCR and ESR
+ * so that another interrupt doesn't come in here and clobber
+ * them before we can use them for our l.rfe */
+ DISABLE_INTERRUPTS(r17,r19)
+ l.mtspr r0,r13,SPR_EPCR_BASE
+ l.mtspr r0,r15,SPR_ESR_BASE
+ l.rfe
+
+/* End of hot path!
+ * Keep the below tracing and error handling out of the hot path...
+*/
+
+_syscall_trace_enter:
+ /* Here we pass pt_regs to do_syscall_trace_enter. Make sure
+ * that function is really getting all the info it needs as
+ * pt_regs isn't a complete set of userspace regs, just the
+ * ones relevant to the syscall...
+ *
+ * Note use of delay slot for setting argument.
+ */
+ l.jal do_syscall_trace_enter
+ l.addi r3,r1,0
+
+ /* Restore arguments (not preserved across do_syscall_trace_enter)
+ * so that we can do the syscall for real and return to the syscall
+ * hot path.
+ */
+ l.lwz r11,PT_GPR11(r1)
+ l.lwz r3,PT_GPR3(r1)
+ l.lwz r4,PT_GPR4(r1)
+ l.lwz r5,PT_GPR5(r1)
+ l.lwz r6,PT_GPR6(r1)
+ l.lwz r7,PT_GPR7(r1)
+
+ l.j _syscall_check
+ l.lwz r8,PT_GPR8(r1)
+
+_syscall_trace_leave:
+ l.jal do_syscall_trace_leave
+ l.addi r3,r1,0
+
+ l.j _syscall_check_work
+ l.nop
+
+_syscall_badsys:
+ /* Here we effectively pretend to have executed an imaginary
+ * syscall that returns -ENOSYS and then return to the regular
+ * syscall hot path.
+ * Note that "return value" is set in the delay slot...
+ */
+ l.j _syscall_return
+ l.addi r11,r0,-ENOSYS
+
+/******* END SYSCALL HANDLING *******/
+
+/* ---[ 0xd00: Trap exception ]------------------------------------------ */
+
+UNHANDLED_EXCEPTION(_vector_0xd00,0xd00)
+
+/* ---[ 0xe00: Trap exception ]------------------------------------------ */
+
+EXCEPTION_ENTRY(_trap_handler)
+ CLEAR_LWA_FLAG(r3)
+ /* r4: EA of fault (set by EXCEPTION_HANDLE) */
+ l.jal do_trap
+ l.addi r3,r1,0 /* pt_regs */
+
+ l.j _ret_from_exception
+ l.nop
+
+/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0xf00,0xf00)
+
+/* ---[ 0x1000: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1000,0x1000)
+
+/* ---[ 0x1100: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1100,0x1100)
+
+/* ---[ 0x1200: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1200,0x1200)
+
+/* ---[ 0x1300: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1300,0x1300)
+
+/* ---[ 0x1400: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1400,0x1400)
+
+/* ---[ 0x1500: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1500,0x1500)
+
+/* ---[ 0x1600: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1600,0x1600)
+
+/* ---[ 0x1700: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1700,0x1700)
+
+/* ---[ 0x1800: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1800,0x1800)
+
+/* ---[ 0x1900: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1900,0x1900)
+
+/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00)
+
+/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00)
+
+/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00)
+
+/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00)
+
+/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00)
+
+/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
+
+UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00)
+
+/* ========================================================[ return ] === */
+
+_resume_userspace:
+ DISABLE_INTERRUPTS(r3,r4)
+ TRACE_IRQS_OFF
+ l.lwz r4,TI_FLAGS(r10)
+ l.andi r13,r4,_TIF_WORK_MASK
+ l.sfeqi r13,0
+ l.bf _restore_all
+ l.nop
+
+_work_pending:
+ l.lwz r5,PT_ORIG_GPR11(r1)
+ l.sfltsi r5,0
+ l.bnf 1f
+ l.nop
+ l.andi r5,r5,0
+1:
+ l.jal do_work_pending
+ l.ori r3,r1,0 /* pt_regs */
+
+ l.sfeqi r11,0
+ l.bf _restore_all
+ l.nop
+ l.sfltsi r11,0
+ l.bnf 1f
+ l.nop
+ l.and r11,r11,r0
+ l.ori r11,r11,__NR_restart_syscall
+ l.j _syscall_check_trace_enter
+ l.nop
+1:
+ l.lwz r11,PT_ORIG_GPR11(r1)
+ /* Restore arg registers */
+ l.lwz r3,PT_GPR3(r1)
+ l.lwz r4,PT_GPR4(r1)
+ l.lwz r5,PT_GPR5(r1)
+ l.lwz r6,PT_GPR6(r1)
+ l.lwz r7,PT_GPR7(r1)
+ l.j _syscall_check_trace_enter
+ l.lwz r8,PT_GPR8(r1)
+
+_restore_all:
+#ifdef CONFIG_TRACE_IRQFLAGS
+ l.lwz r4,PT_SR(r1)
+ l.andi r3,r4,(SPR_SR_IEE|SPR_SR_TEE)
+ l.sfeq r3,r0 /* skip trace if irqs were off */
+ l.bf skip_hardirqs_on
+ l.nop
+ TRACE_IRQS_ON
+skip_hardirqs_on:
+#endif
+ RESTORE_ALL
+ /* This returns to userspace code */
+
+
+ENTRY(_ret_from_intr)
+ENTRY(_ret_from_exception)
+ l.lwz r4,PT_SR(r1)
+ l.andi r3,r4,SPR_SR_SM
+ l.sfeqi r3,0
+ l.bnf _restore_all
+ l.nop
+ l.j _resume_userspace
+ l.nop
+
+ENTRY(ret_from_fork)
+ l.jal schedule_tail
+ l.nop
+
+ /* Check if we are a kernel thread */
+ l.sfeqi r20,0
+ l.bf 1f
+ l.nop
+
+ /* ...we are a kernel thread so invoke the requested callback */
+ l.jalr r20
+ l.or r3,r22,r0
+
+1:
+ /* _syscall_returns expect r11 to contain return value */
+ l.lwz r11,PT_GPR11(r1)
+
+ /* The syscall fast path return expects call-saved registers
+ * r12-r28 to be untouched, so we restore them here as they
+ * will have been effectively clobbered when arriving here
+ * via the call to switch()
+ */
+ l.lwz r12,PT_GPR12(r1)
+ l.lwz r14,PT_GPR14(r1)
+ l.lwz r16,PT_GPR16(r1)
+ l.lwz r18,PT_GPR18(r1)
+ l.lwz r20,PT_GPR20(r1)
+ l.lwz r22,PT_GPR22(r1)
+ l.lwz r24,PT_GPR24(r1)
+ l.lwz r26,PT_GPR26(r1)
+ l.lwz r28,PT_GPR28(r1)
+
+ l.j _syscall_return
+ l.nop
+
+/* ========================================================[ switch ] === */
+
+/*
+ * This routine switches between two different tasks. The process
+ * state of one is saved on its kernel stack. Then the state
+ * of the other is restored from its kernel stack. The memory
+ * management hardware is updated to the second process's state.
+ * Finally, we can return to the second process, via the 'return'.
+ *
+ * Note: there are two ways to get to the "going out" portion
+ * of this code; either by coming in via the entry (_switch)
+ * or via "fork" which must set up an environment equivalent
+ * to the "_switch" path. If you change this (or in particular, the
+ * SAVE_REGS macro), you'll have to change the fork code also.
+ */
+
+
+/* _switch MUST never lay on page boundry, cause it runs from
+ * effective addresses and beeing interrupted by iTLB miss would kill it.
+ * dTLB miss seams to never accour in the bad place since data accesses
+ * are from task structures which are always page aligned.
+ *
+ * The problem happens in RESTORE_ALL_NO_R11 where we first set the EPCR
+ * register, then load the previous register values and only at the end call
+ * the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets
+ * garbled and we end up calling l.rfe with the wrong EPCR. (same probably
+ * holds for ESR)
+ *
+ * To avoid this problems it is sufficient to align _switch to
+ * some nice round number smaller than it's size...
+ */
+
+/* ABI rules apply here... we either enter _switch via schedule() or via
+ * an imaginary call to which we shall return at return_from_fork. Either
+ * way, we are a function call and only need to preserve the callee-saved
+ * registers when we return. As such, we don't need to save the registers
+ * on the stack that we won't be returning as they were...
+ */
+
+ .align 0x400
+ENTRY(_switch)
+ /* We don't store SR as _switch only gets called in a context where
+ * the SR will be the same going in and coming out... */
+
+ /* Set up new pt_regs struct for saving task state */
+ l.addi r1,r1,-(INT_FRAME_SIZE)
+
+ /* No need to store r1/PT_SP as it goes into KSP below */
+ l.sw PT_GPR2(r1),r2
+ l.sw PT_GPR9(r1),r9
+ /* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
+ * and expects r12 to be callee-saved... */
+ l.sw PT_GPR12(r1),r12
+ l.sw PT_GPR14(r1),r14
+ l.sw PT_GPR16(r1),r16
+ l.sw PT_GPR18(r1),r18
+ l.sw PT_GPR20(r1),r20
+ l.sw PT_GPR22(r1),r22
+ l.sw PT_GPR24(r1),r24
+ l.sw PT_GPR26(r1),r26
+ l.sw PT_GPR28(r1),r28
+ l.sw PT_GPR30(r1),r30
+
+ l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/
+
+ /* We use thread_info->ksp for storing the address of the above
+ * structure so that we can get back to it later... we don't want
+ * to lose the value of thread_info->ksp, though, so store it as
+ * pt_regs->sp so that we can easily restore it when we are made
+ * live again...
+ */
+
+ /* Save the old value of thread_info->ksp as pt_regs->sp */
+ l.lwz r29,TI_KSP(r10)
+ l.sw PT_SP(r1),r29
+
+ /* Swap kernel stack pointers */
+ l.sw TI_KSP(r10),r1 /* Save old stack pointer */
+ l.or r10,r4,r0 /* Set up new current_thread_info */
+ l.lwz r1,TI_KSP(r10) /* Load new stack pointer */
+
+ /* Restore the old value of thread_info->ksp */
+ l.lwz r29,PT_SP(r1)
+ l.sw TI_KSP(r10),r29
+
+ /* ...and restore the registers, except r11 because the return value
+ * has already been set above.
+ */
+ l.lwz r2,PT_GPR2(r1)
+ l.lwz r9,PT_GPR9(r1)
+ /* No need to restore r10 */
+ /* ...and do not restore r11 */
+
+ /* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
+ * and expects r12 to be callee-saved... */
+ l.lwz r12,PT_GPR12(r1)
+ l.lwz r14,PT_GPR14(r1)
+ l.lwz r16,PT_GPR16(r1)
+ l.lwz r18,PT_GPR18(r1)
+ l.lwz r20,PT_GPR20(r1)
+ l.lwz r22,PT_GPR22(r1)
+ l.lwz r24,PT_GPR24(r1)
+ l.lwz r26,PT_GPR26(r1)
+ l.lwz r28,PT_GPR28(r1)
+ l.lwz r30,PT_GPR30(r1)
+
+ /* Unwind stack to pre-switch state */
+ l.addi r1,r1,(INT_FRAME_SIZE)
+
+ /* Return via the link-register back to where we 'came from', where
+ * that may be either schedule(), ret_from_fork(), or
+ * ret_from_kernel_thread(). If we are returning to a new thread,
+ * we are expected to have set up the arg to schedule_tail already,
+ * hence we do so here unconditionally:
+ */
+ l.lwz r3,TI_TASK(r3) /* Load 'prev' as schedule_tail arg */
+ l.jr r9
+ l.nop
+
+/* ==================================================================== */
+
+/* These all use the delay slot for setting the argument register, so the
+ * jump is always happening after the l.addi instruction.
+ *
+ * These are all just wrappers that don't touch the link-register r9, so the
+ * return from the "real" syscall function will return back to the syscall
+ * code that did the l.jal that brought us here.
+ */
+
+/* fork requires that we save all the callee-saved registers because they
+ * are all effectively clobbered by the call to _switch. Here we store
+ * all the registers that aren't touched by the syscall fast path and thus
+ * weren't saved there.
+ */
+
+_fork_save_extra_regs_and_call:
+ l.sw PT_GPR14(r1),r14
+ l.sw PT_GPR16(r1),r16
+ l.sw PT_GPR18(r1),r18
+ l.sw PT_GPR20(r1),r20
+ l.sw PT_GPR22(r1),r22
+ l.sw PT_GPR24(r1),r24
+ l.sw PT_GPR26(r1),r26
+ l.jr r29
+ l.sw PT_GPR28(r1),r28
+
+ENTRY(__sys_clone)
+ l.movhi r29,hi(sys_clone)
+ l.ori r29,r29,lo(sys_clone)
+ l.j _fork_save_extra_regs_and_call
+ l.nop
+
+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.nop
+
+ENTRY(sys_rt_sigreturn)
+ l.jal _sys_rt_sigreturn
+ l.addi r3,r1,0
+ l.sfne r30,r0
+ l.bnf _no_syscall_trace
+ l.nop
+ l.jal do_syscall_trace_leave
+ l.addi r3,r1,0
+_no_syscall_trace:
+ l.j _resume_userspace
+ l.nop
+
+/* This is a catch-all syscall for atomic instructions for the OpenRISC 1000.
+ * The functions takes a variable number of parameters depending on which
+ * particular flavour of atomic you want... parameter 1 is a flag identifying
+ * the atomic in question. Currently, this function implements the
+ * following variants:
+ *
+ * XCHG:
+ * @flag: 1
+ * @ptr1:
+ * @ptr2:
+ * Atomically exchange the values in pointers 1 and 2.
+ *
+ */
+
+ENTRY(sys_or1k_atomic)
+ /* FIXME: This ignores r3 and always does an XCHG */
+ DISABLE_INTERRUPTS(r17,r19)
+ l.lwz r29,0(r4)
+ l.lwz r27,0(r5)
+ l.sw 0(r4),r27
+ l.sw 0(r5),r29
+ ENABLE_INTERRUPTS(r17)
+ l.jr r9
+ l.or r11,r0,r0
+
+/* ============================================================[ EOF ]=== */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-30 21:36:12 +0000