source: mainline/kernel/arch/ppc32/src/exception.S

#
# Copyright (c) 2006 Martin Decky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

#include <abi/asmtool.h>
#include <arch/asm/regname.h>
#include <arch/msr.h>
#include <arch/mm/page.h>
#include <arch/istate_struct.h>
#include <arch/stack.h>
#include <align.h>

.section K_UNMAPPED_TEXT_START, "ax"

.macro CONTEXT_STORE

        # save r12 in SPRG1, backup CR in r12
        # save SP in SPRG2

        mtsprg1 r12
        mfcr r12
        mtsprg2 sp

        # check whether the previous mode was user or kernel

        mfsrr1 sp # use sp as a temporary register to hold SRR1
        andi. sp, sp, MSR_PR
        bne 1f
                # previous mode was kernel

                mfsprg2 sp
                subis sp, sp, 0x8000
        b 2f

        1:
                # previous mode was user

                mfsprg0 sp
        2:

        subi sp, sp, ALIGN_UP(ISTATE_SIZE, STACK_ALIGNMENT)
        stw r0, ISTATE_OFFSET_R0(sp)
        stw r2, ISTATE_OFFSET_R2(sp)
        stw r3, ISTATE_OFFSET_R3(sp)
        stw r4, ISTATE_OFFSET_R4(sp)
        stw r5, ISTATE_OFFSET_R5(sp)
        stw r6, ISTATE_OFFSET_R6(sp)
        stw r7, ISTATE_OFFSET_R7(sp)
        stw r8, ISTATE_OFFSET_R8(sp)
        stw r9, ISTATE_OFFSET_R9(sp)
        stw r10, ISTATE_OFFSET_R10(sp)
        stw r11, ISTATE_OFFSET_R11(sp)
        stw r13, ISTATE_OFFSET_R13(sp)
        stw r14, ISTATE_OFFSET_R14(sp)
        stw r15, ISTATE_OFFSET_R15(sp)
        stw r16, ISTATE_OFFSET_R16(sp)
        stw r17, ISTATE_OFFSET_R17(sp)
        stw r18, ISTATE_OFFSET_R18(sp)
        stw r19, ISTATE_OFFSET_R19(sp)
        stw r20, ISTATE_OFFSET_R20(sp)
        stw r21, ISTATE_OFFSET_R21(sp)
        stw r22, ISTATE_OFFSET_R22(sp)
        stw r23, ISTATE_OFFSET_R23(sp)
        stw r24, ISTATE_OFFSET_R24(sp)
        stw r25, ISTATE_OFFSET_R25(sp)
        stw r26, ISTATE_OFFSET_R26(sp)
        stw r27, ISTATE_OFFSET_R27(sp)
        stw r28, ISTATE_OFFSET_R28(sp)
        stw r29, ISTATE_OFFSET_R29(sp)
        stw r30, ISTATE_OFFSET_R30(sp)
        stw r31, ISTATE_OFFSET_R31(sp)

        stw r12, ISTATE_OFFSET_CR(sp)

        mfsrr0 r12
        stw r12, ISTATE_OFFSET_PC(sp)

        mfsrr1 r12
        stw r12, ISTATE_OFFSET_SRR1(sp)

        mflr r12
        stw r12, ISTATE_OFFSET_LR(sp)

        mfctr r12
        stw r12, ISTATE_OFFSET_CTR(sp)

        mfxer r12
        stw r12, ISTATE_OFFSET_XER(sp)

        mfdar r12
        stw r12, ISTATE_OFFSET_DAR(sp)

        mfsprg1 r12
        stw r12, ISTATE_OFFSET_R12(sp)

        mfsprg2 r12
        stw r12, ISTATE_OFFSET_SP(sp)

        li r12, 0
        stw r12, ISTATE_OFFSET_LR_FRAME(sp)
        stw r12, ISTATE_OFFSET_SP_FRAME(sp)
.endm

// NOTE: K_UNMAPPED_TEXT_START section starts at 0x100,
// so all the following .org directives are relative to that.
#define ABSOLUTE(x) ((x) - 0x100)

.org ABSOLUTE(0x100)
SYMBOL(exc_system_reset)
        CONTEXT_STORE

        li r3, 0
        b jump_to_kernel

.org ABSOLUTE(0x200)
SYMBOL(exc_machine_check)
        CONTEXT_STORE

        li r3, 1
        b jump_to_kernel

.org ABSOLUTE(0x300)
SYMBOL(exc_data_storage)
        CONTEXT_STORE

        li r3, 2
        b jump_to_kernel

.org ABSOLUTE(0x400)
SYMBOL(exc_instruction_storage)
        CONTEXT_STORE

        li r3, 3
        b jump_to_kernel

.org ABSOLUTE(0x500)
SYMBOL(exc_external)
        CONTEXT_STORE

        li r3, 4
        b jump_to_kernel

.org ABSOLUTE(0x600)
SYMBOL(exc_alignment)
        CONTEXT_STORE

        li r3, 5
        b jump_to_kernel

.org ABSOLUTE(0x700)
SYMBOL(exc_program)
        CONTEXT_STORE

        li r3, 6
        b jump_to_kernel

.org ABSOLUTE(0x800)
SYMBOL(exc_fp_unavailable)
        CONTEXT_STORE

        li r3, 7
        b jump_to_kernel

.org ABSOLUTE(0x900)
SYMBOL(exc_decrementer)
        CONTEXT_STORE

        li r3, 8
        b jump_to_kernel

.org ABSOLUTE(0xa00)
SYMBOL(exc_reserved0)
        CONTEXT_STORE

        li r3, 9
        b jump_to_kernel

.org ABSOLUTE(0xb00)
SYMBOL(exc_reserved1)
        CONTEXT_STORE

        li r3, 10
        b jump_to_kernel

.org ABSOLUTE(0xc00)
SYMBOL(exc_syscall)
        CONTEXT_STORE

        b jump_to_kernel_syscall

.org ABSOLUTE(0xd00)
SYMBOL(exc_trace)
        CONTEXT_STORE

        li r3, 12
        b jump_to_kernel

.org ABSOLUTE(0x1000)
SYMBOL(exc_itlb_miss)
        CONTEXT_STORE

        li r3, 13
        b jump_to_kernel

.org ABSOLUTE(0x1100)
SYMBOL(exc_dtlb_miss_load)
        CONTEXT_STORE

        li r3, 14
        b jump_to_kernel

.org ABSOLUTE(0x1200)
SYMBOL(exc_dtlb_miss_store)
        CONTEXT_STORE

        li r3, 15
        b jump_to_kernel

.org ABSOLUTE(0x4000)
jump_to_kernel:
        mfsrr1 r5
        andi. r5, r5, MSR_PR
        bne 1f
                # Previous mode was kernel.
                # We can construct a proper frame linkage.

                mfsrr0 r12
                stw r12, ISTATE_OFFSET_LR_FRAME(sp)
                mfsprg2 r12
                stw r12, ISTATE_OFFSET_SP_FRAME(sp)
        1:

        lis r12, iret@ha
        addi r12, r12, iret@l
        mtlr r12

        lis r12, exc_dispatch@ha
        addi r12, r12, exc_dispatch@l
        mtsrr0 r12

        mfmsr r12
        mfsrr1 r5
        andi. r5, r5, MSR_FP
        or r12, r12, r5         # Propagate MSR_FP from SRR1 to MSR
        ori r12, r12, (MSR_IR | MSR_DR)
        mtsrr1 r12

        addis sp, sp, 0x8000
        mr r4, sp

        rfi

jump_to_kernel_syscall:
        lis r12, syscall_handler@ha
        addi r12, r12, syscall_handler@l
        mtsrr0 r12

        lis r12, iret_syscall@ha
        addi r12, r12, iret_syscall@l
        mtlr r12

        mfsrr1 r0
        andi. r0, r0, MSR_FP
        mfmsr r12
        or r12, r12, r0         # Propagate MSR_FP from SRR1 to MSR
        ori r12, r12, (MSR_IR | MSR_DR | MSR_EE)
        mtsrr1 r12

        addis sp, sp, 0x8000
        rfi

/* Rest is for stack. */

.org ABSOLUTE(0x8000)