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发表于 2005-6-16 11:13:22
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谢谢回复，但是接下来的问题是这样的::::
SMDK2410的板子不用修改，编译就能运行，看见启动信息了。我照坐，就是不行!!!
Copy linux kernel from 0x00030000 to 0x30008000, size = 0x001c0000 ... done
zImage magic = 0x016f2818
Setup linux parameters at 0x30000100
linux command line is: "noinitrd root=/dev/mtdblock/3 init=/linuxrc console=ttySAC0 mac=00:0e:3a:aa:bb:cc"
MACH_TYPE = 193
NOW, Booting Linux......
Uncompressing Linux.............................................................
. done, booting the kernel.
在优龙的板子上跑2.6.11都没有问题。看他们的硬件和我们手头上的几乎是一样的
，在存储器配置和硬件地址分配上。SDRAM从0x30000000.
我追踪内核启动到arch\arm\kernel\head.S文件里.基本内容如下:
/*
* Kernel startup entry point.
* ---------------------------
*
* This is normally called from the decompressor code. The requirements
* are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0,
* r1 = machine nr.
*
* This code is mostly position independent, so if you link the kernel at
* 0xc0008000, you call this at __pa(0xc0008000).
*
* See linux/arch/arm/tools/mach-types for the complete list of machine
* numbers for r1.
*
* We're trying to keep crap to a minimum; DO NOT add any machine specific
* crap here - that's what the boot loader (or in extreme, well justified
* circumstances, zImage) is for.
*/
__INIT
.type stext, %function
ENTRY(stext)
msr cpsr_c, #PSR_F_BIT | PSR_I_BIT | MODE_SVC @ ensure svc mode
@ and irqs disabled
bl __lookup_processor_type @ r5=procinfo r9=cpuid
movs r10, r5 @ invalid processor (r5=0)?
moveq r0, #'p' @ yes, error 'p'
beq __error
bl __lookup_machine_type @ r5=machinfo
movs r8, r5 @ invalid machine (r5=0)?
moveq r0, #'a' @ yes, error 'a'
beq __error
bl __create_page_tables
/*
moveq r0, #'1'
bl printch
*/
/*
* The following calls CPU specific code in a position independent
* manner. See arch/arm/mm/proc-*.S for details. r10 = base of
* xxx_proc_info structure selected by __lookup_machine_type
* above. On return, the CPU will be ready for the MMU to be
* turned on, and r0 will hold the CPU control register value.
*/
ldr r13, __switch_data @ address to jump to after
@ mmu has been enabled
adr lr, __enable_mmu @ return (PIC) address
add pc, r10, #PROCINFO_INITFUNC
.type __switch_data, %object
__switch_data:
.long __mmap_switched
.long __data_loc @ r4
.long __data_start @ r5
.long __bss_start @ r6
.long _end @ r7
.long processor_id @ r4
.long __machine_arch_type @ r5
.long cr_alignment @ r6
.long init_thread_union+8192 @ sp
/*
* The following fragment of code is executed with the MMU on, and uses
* absolute addresses; this is not position independent.
*
* r0 = cp#15 control register
* r1 = machine ID
* r9 = processor ID
*/
.type __mmap_switched, %function
__mmap_switched:
adr r3, __switch_data + 4
ldmia r3!, {r4, r5, r6, r7}
cmp r4, r5 @ Copy data segment if needed
1: cmpne r5, r6
ldrne fp, [r4], #4
strne fp, [r5], #4
bne 1b
mov fp, #0 @ Clear BSS (and zero fp)
1: cmp r6, r7
strcc fp, [r6],#4
bcc 1b
ldmia r3, {r4, r5, r6, sp}
str r9, [r4] @ Save processor ID
str r1, [r5] @ Save machine type
bic r4, r0, #CR_A @ Clear 'A' bit
stmia r6, {r0, r4} @ Save control register values
b start_kernel
假如以上的代码执行无误，应该开始跳到C的入口start_kernel了。
我在这个之前插入打印
moveq r0, #'1'
bl printch
在b start_kernel前发现能执行到这里.输出"1"这个字符了。然后我移除这两条语句.
然后就应该执行/init/main.c里的start_kernel函数了
于是我跳到main.c的start_kernel函数，
/*
* Activate the first processor.
*/
/* we can deal with the case the UARTs are being run
* in FIFO mode, so that we don't hold up our execution
* waiting for tx to happen...
*/
asmlinkage void __init start_kernel(void)
{
char * command_line;
extern struct kernel_param __start___param[], __stop___param[];
/*
* Interrupts are still disabled. Do necessary setups, then
* enable them
*/
printk("kdjsfhskf\n");
mdelay(1000);
lock_kernel();
page_address_init();
printk(linux_banner);
setup_arch(&command_line);
setup_per_cpu_areas();
/*
* Mark the boot cpu "online" so that it can call console drivers in
* printk() and can access its per-cpu storage.
*/
smp_prepare_boot_cpu();
/*
* Set up the scheduler prior starting any interrupts (such as the
* timer interrupt). Full topology setup happens at smp_init()
* time - but meanwhile we still have a functioning scheduler.
*/
sched_init();
/*
* Disable preemption - early bootup scheduling is extremely
* fragile until we cpu_idle() for the first time.
*/
preempt_disable();
build_all_zonelists();
page_alloc_init();
printk("Kernel command line: %s\n", saved_command_line);
parse_early_param();
parse_args("Booting kernel", command_line, __start___param,
__stop___param - __start___param,
&unknown_bootoption);
sort_main_extable();
trap_init();
.....................
粗体的使我添加的。但是串口没有打印我插入的打印文字.......
难道，在head.S里没有正确跳转到start_kernel还是 printk()函数没有作用?????
继续研究哟!!! |
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