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Atmosphere/thermosphere/src/start.s

125 lines
3.1 KiB
ArmAsm

/*
* Copyright (c) 2019 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "asm_macros.s"
.section .crt0, "ax", %progbits
.align 3
.global _start
.type _start, %function
_start:
b start
b start2
.global g_initialKernelEntrypoint
g_initialKernelEntrypoint:
.quad 0
start:
mov x19, #1
b _startCommon
start2:
mov x19, xzr
_startCommon:
// Disable interrupts, select sp_el0 before mmu is enabled
mrs x20, cntpct_el0
msr daifset, 0b1111
msr spsel, #0
// Set sctlr_el2 ASAP to disable mmu/caching if not already done.
mov x1, #0x0838
movk x1, #0x30C5,lsl #16
msr sctlr_el2, x1
dsb sy
isb
// Save x0
mov x21, x0
bl cacheClearLocalDataCacheOnBoot
cbz x19, 1f
// "Boot core only" stuff:
bl cacheClearSharedDataCachesOnBoot
ic iallu
dsb nsh
isb
// Temporarily use temp end region as stack, then create the translation table
// The stack top is also equal to the mmu table address...
adr x0, g_loadImageLayout
ldp x2, x3, [x0, #0x10]
add x1, x2, x3
mov sp, x1
bl memoryMapSetupMmu
1:
// Enable MMU, note that the function is not allowed to use any stack
adr x0, g_loadImageLayout
ldr x18, =_postMmuEnableReturnAddr
bl memoryMapEnableMmu
// This is where we will land on exception return after enabling the MMU:
_postMmuEnableReturnAddr:
// Select sp_el2
msr spsel, #1
// Get core ID
mrs x8, mpidr_el1
and x8, x8, #0xFF
mov w0, w8
bl memoryMapGetStackTop
mov sp, x0
// Set up x18, other sysregs, BSS, etc.
// Don't call init array to save space?
mov w0, w8
mov w1, w19
mov x2, x21
bl initSystem
// Save x18, reserve space for exception frame
stp x18, xzr, [sp, #-0x10]!
sub sp, sp, #EXCEP_STACK_FRAME_SIZE
mov x0, sp
mov x1, x20
str x0, [x18, #CORECTX_GUEST_FRAME_OFFSET]
bl thermosphereMain
prfm pldl1keep, [x18]
prfm pstl1keep, [x18, #0x40]
dsb sy
isb
// Jump to kernel
mov x0, sp
bl exceptionReturnPreprocess
b _restoreAllRegisters
.pool
.global g_loadImageLayout
g_loadImageLayout:
.quad __start_pa__
.quad __image_size__
.quad __temp_pa__
.quad __max_temp_size__
.quad __temp_size__
.quad __vectors_start__