diff options
Diffstat (limited to 'arch/arc/kernel/head.S')
| -rw-r--r-- | arch/arc/kernel/head.S | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S new file mode 100644 index 00000000000..006dec3fc35 --- /dev/null +++ b/arch/arc/kernel/head.S @@ -0,0 +1,111 @@ +/* + * ARC CPU startup Code + * + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Vineetg: Dec 2007 + * -Check if we are running on Simulator or on real hardware + * to skip certain things during boot on simulator + */ + +#include <asm/asm-offsets.h> +#include <asm/entry.h> +#include <linux/linkage.h> +#include <asm/arcregs.h> + + .cpu A7 + + .section .init.text, "ax",@progbits + .type stext, @function + .globl stext +stext: + ;------------------------------------------------------------------- + ; Don't clobber r0-r4 yet. It might have bootloader provided info + ;------------------------------------------------------------------- + +#ifdef CONFIG_SMP + ; Only Boot (Master) proceeds. Others wait in platform dependent way + ; IDENTITY Reg [ 3 2 1 0 ] + ; (cpu-id) ^^^ => Zero for UP ARC700 + ; => #Core-ID if SMP (Master 0) + GET_CPU_ID r5 + cmp r5, 0 + jnz arc_platform_smp_wait_to_boot +#endif + ; Clear BSS before updating any globals + ; XXX: use ZOL here + mov r5, __bss_start + mov r6, __bss_stop +1: + st.ab 0, [r5,4] + brlt r5, r6, 1b + +#ifdef CONFIG_CMDLINE_UBOOT + ; support for bootloader provided cmdline + ; If cmdline passed by u-boot, then + ; r0 = 1 (because ATAGS parsing, now retired, used to use 0) + ; r1 = magic number (board identity) + ; r2 = addr of cmdline string (somewhere in memory/flash) + + brne r0, 1, .Lother_bootup_chores ; u-boot didn't pass cmdline + breq r2, 0, .Lother_bootup_chores ; or cmdline is NULL + + mov r5, @command_line +1: + ldb.ab r6, [r2, 1] + breq r6, 0, .Lother_bootup_chores + b.d 1b + stb.ab r6, [r5, 1] +#endif + +.Lother_bootup_chores: + + ; Identify if running on ISS vs Silicon + ; IDENTITY Reg [ 3 2 1 0 ] + ; (chip-id) ^^^^^ ==> 0xffff for ISS + lr r0, [identity] + lsr r3, r0, 16 + cmp r3, 0xffff + mov.z r4, 0 + mov.nz r4, 1 + st r4, [@running_on_hw] + + ; setup "current" tsk and optionally cache it in dedicated r25 + mov r9, @init_task + SET_CURR_TASK_ON_CPU r9, r0 ; r9 = tsk, r0 = scratch + + ; setup stack (fp, sp) + mov fp, 0 + + ; tsk->thread_info is really a PAGE, whose bottom hoists stack + GET_TSK_STACK_BASE r9, sp ; r9 = tsk, sp = stack base(output) + + j start_kernel ; "C" entry point + +#ifdef CONFIG_SMP +;---------------------------------------------------------------- +; First lines of code run by secondary before jumping to 'C' +;---------------------------------------------------------------- + .section .init.text, "ax",@progbits + .type first_lines_of_secondary, @function + .globl first_lines_of_secondary + +first_lines_of_secondary: + + ; setup per-cpu idle task as "current" on this CPU + ld r0, [@secondary_idle_tsk] + SET_CURR_TASK_ON_CPU r0, r1 + + ; setup stack (fp, sp) + mov fp, 0 + + ; set it's stack base to tsk->thread_info bottom + GET_TSK_STACK_BASE r0, sp + + j start_kernel_secondary + +#endif |