diff options
Diffstat (limited to 'arch/sh/kernel/head_32.S')
| -rw-r--r-- | arch/sh/kernel/head_32.S | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/arch/sh/kernel/head_32.S b/arch/sh/kernel/head_32.S new file mode 100644 index 00000000000..d67d7ed09f2 --- /dev/null +++ b/arch/sh/kernel/head_32.S @@ -0,0 +1,124 @@ +/* $Id: head.S,v 1.7 2003/09/01 17:58:19 lethal Exp $ + * + * arch/sh/kernel/head.S + * + * Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima + * + * 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. + * + * Head.S contains the SH exception handlers and startup code. + */ +#include <linux/linkage.h> +#include <asm/thread_info.h> + +#ifdef CONFIG_CPU_SH4A +#define SYNCO() synco + +#define PREFI(label, reg) \ + mov.l label, reg; \ + prefi @reg +#else +#define SYNCO() +#define PREFI(label, reg) +#endif + + .section .empty_zero_page, "aw" +ENTRY(empty_zero_page) + .long 1 /* MOUNT_ROOT_RDONLY */ + .long 0 /* RAMDISK_FLAGS */ + .long 0x0200 /* ORIG_ROOT_DEV */ + .long 1 /* LOADER_TYPE */ + .long 0x00360000 /* INITRD_START */ + .long 0x000a0000 /* INITRD_SIZE */ +#ifdef CONFIG_32BIT + .long 0x53453f00 + 32 /* "SE?" = 32 bit */ +#else + .long 0x53453f00 + 29 /* "SE?" = 29 bit */ +#endif +1: + .skip PAGE_SIZE - empty_zero_page - 1b + + .section .text.head, "ax" + +/* + * Condition at the entry of _stext: + * + * BSC has already been initialized. + * INTC may or may not be initialized. + * VBR may or may not be initialized. + * MMU may or may not be initialized. + * Cache may or may not be initialized. + * Hardware (including on-chip modules) may or may not be initialized. + * + */ +ENTRY(_stext) + ! Initialize Status Register + mov.l 1f, r0 ! MD=1, RB=0, BL=0, IMASK=0xF + ldc r0, sr + ! Initialize global interrupt mask +#ifdef CONFIG_CPU_HAS_SR_RB + mov #0, r0 + ldc r0, r6_bank +#endif + + /* + * Prefetch if possible to reduce cache miss penalty. + * + * We do this early on for SH-4A as a micro-optimization, + * as later on we will have speculative execution enabled + * and this will become less of an issue. + */ + PREFI(5f, r0) + PREFI(6f, r0) + + ! + mov.l 2f, r0 + mov r0, r15 ! Set initial r15 (stack pointer) +#ifdef CONFIG_CPU_HAS_SR_RB + mov.l 7f, r0 + ldc r0, r7_bank ! ... and initial thread_info +#endif + + ! Clear BSS area +#ifdef CONFIG_SMP + mov.l 3f, r0 + cmp/eq #0, r0 ! skip clear if set to zero + bt 10f +#endif + + mov.l 3f, r1 + add #4, r1 + mov.l 4f, r2 + mov #0, r0 +9: cmp/hs r2, r1 + bf/s 9b ! while (r1 < r2) + mov.l r0,@-r2 + +10: + ! Additional CPU initialization + mov.l 6f, r0 + jsr @r0 + nop + + SYNCO() ! Wait for pending instructions.. + + ! Start kernel + mov.l 5f, r0 + jmp @r0 + nop + + .balign 4 +#if defined(CONFIG_CPU_SH2) +1: .long 0x000000F0 ! IMASK=0xF +#else +1: .long 0x400080F0 ! MD=1, RB=0, BL=0, FD=1, IMASK=0xF +#endif +ENTRY(stack_start) +2: .long init_thread_union+THREAD_SIZE +3: .long __bss_start +4: .long _end +5: .long start_kernel +6: .long sh_cpu_init +7: .long init_thread_union |