mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-11-30 08:46:43 +07:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
129 lines
3.9 KiB
ArmAsm
129 lines
3.9 KiB
ArmAsm
/*
|
|
* arch/v850/kernel/head.S -- Lowest-level startup code
|
|
*
|
|
* Copyright (C) 2001,02,03 NEC Electronics Corporation
|
|
* Copyright (C) 2001,02,03 Miles Bader <miles@gnu.org>
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General
|
|
* Public License. See the file COPYING in the main directory of this
|
|
* archive for more details.
|
|
*
|
|
* Written by Miles Bader <miles@gnu.org>
|
|
*/
|
|
|
|
#include <asm/clinkage.h>
|
|
#include <asm/current.h>
|
|
#include <asm/entry.h>
|
|
#include <asm/thread_info.h>
|
|
#include <asm/irq.h>
|
|
|
|
|
|
/* Make a slightly more convenient alias for C_SYMBOL_NAME. */
|
|
#define CSYM C_SYMBOL_NAME
|
|
|
|
|
|
.text
|
|
|
|
// Define `mach_early_init' as a weak symbol
|
|
.global CSYM(mach_early_init)
|
|
.weak CSYM(mach_early_init)
|
|
|
|
C_ENTRY(start):
|
|
// Make sure interrupts are turned off, just in case
|
|
di
|
|
|
|
#ifdef CONFIG_RESET_GUARD
|
|
// See if we got here via an unexpected reset
|
|
ld.w RESET_GUARD, r19 // Check current value of reset guard
|
|
mov RESET_GUARD_ACTIVE, r20
|
|
cmp r19, r20
|
|
bne 1f // Guard was not active
|
|
|
|
// If we get here, the reset guard was active. Load up some
|
|
// interesting values as arguments, and jump to the handler.
|
|
st.w r0, RESET_GUARD // Allow further resets to succeed
|
|
mov lp, r6 // Arg 0: return address
|
|
ld.b KM, r7 // Arg 1: kernel mode
|
|
mov sp, r9 // Arg 3: stack pointer
|
|
ld.w KSP, r19 // maybe switch to kernel stack
|
|
cmp r7, r0 // see if already in kernel mode
|
|
cmov z, r19, sp, sp // and switch to kernel stack if not
|
|
GET_CURRENT_TASK(r8) // Arg 2: task pointer
|
|
jr CSYM(unexpected_reset)
|
|
|
|
1: st.w r20, RESET_GUARD // Turn on reset guard
|
|
#endif /* CONFIG_RESET_GUARD */
|
|
|
|
// Setup a temporary stack for doing pre-initialization function calls.
|
|
//
|
|
// We can't use the initial kernel stack, because (1) it may be
|
|
// located in memory we're not allowed to touch, and (2) since
|
|
// it's in the data segment, calling memcpy to initialize that
|
|
// area from ROM will overwrite memcpy's return address.
|
|
mov hilo(CSYM(_init_stack_end) - 4), sp
|
|
|
|
// See if there's a platform-specific early-initialization routine
|
|
// defined; it's a weak symbol, so it will have an address of zero if
|
|
// there's not.
|
|
mov hilo(CSYM(mach_early_init)), r6
|
|
cmp r6, r0
|
|
bz 3f
|
|
|
|
// There is one, so call it. If this function is written in C, it
|
|
// should be very careful -- the stack pointer is valid, but very
|
|
// little else is (e.g., bss is not zeroed yet, and initialized data
|
|
// hasn't been).
|
|
jarl 2f, lp // first figure out return address
|
|
2: add 3f - ., lp
|
|
jmp [r6] // do call
|
|
3:
|
|
|
|
#ifdef CONFIG_ROM_KERNEL
|
|
// Copy the data area from ROM to RAM
|
|
mov hilo(CSYM(_rom_copy_dst_start)), r6
|
|
mov hilo(CSYM(_rom_copy_src_start)), r7
|
|
mov hilo(CSYM(_rom_copy_dst_end)), r8
|
|
sub r6, r8
|
|
jarl CSYM(memcpy), lp
|
|
#endif
|
|
|
|
// Load the initial thread's stack, and current task pointer (in r16)
|
|
mov hilo(CSYM(init_thread_union)), r19
|
|
movea THREAD_SIZE, r19, sp
|
|
ld.w TI_TASK[r19], CURRENT_TASK
|
|
|
|
#ifdef CONFIG_TIME_BOOTUP
|
|
/* This stuff must come after mach_early_init, because interrupts may
|
|
not work until after its been called. */
|
|
jarl CSYM(highres_timer_reset), lp
|
|
jarl CSYM(highres_timer_start), lp
|
|
#endif
|
|
|
|
// Kernel stack pointer save location
|
|
st.w sp, KSP
|
|
|
|
// Assert that we're in `kernel mode'
|
|
mov 1, r19
|
|
st.w r19, KM
|
|
|
|
#ifdef CONFIG_ZERO_BSS
|
|
// Zero bss area, since we can't rely upon any loader to do so
|
|
mov hilo(CSYM(_sbss)), r6
|
|
mov r0, r7
|
|
mov hilo(CSYM(_ebss)), r8
|
|
sub r6, r8
|
|
jarl CSYM(memset), lp
|
|
#endif
|
|
|
|
// What happens if the main kernel function returns (it shouldn't)
|
|
mov hilo(CSYM(machine_halt)), lp
|
|
|
|
// Start the linux kernel. We use an indirect jump to get extra
|
|
// range, because on some platforms this initial startup code
|
|
// (and the associated platform-specific code in mach_early_init)
|
|
// are located far away from the main kernel, e.g. so that they
|
|
// can initialize RAM first and copy the kernel or something.
|
|
mov hilo(CSYM(start_kernel)), r12
|
|
jmp [r12]
|
|
C_END(start)
|