ARM Linux中断机制分析

~/arch/arm/kernel/traps.c line783

void __init early_trap_init(void)

{

#if defined(CONFIG_CPU_USE_DOMAINS)

unsigned longvectors = CONFIG_VECTORS_BASE; //vectors是中断向量基地址

#else

unsigned long vectors = (unsigned long)vectors_page;

#endif

/*以下这些都在arch/arm/kernel/entry-armv.S下定义*/

extern char __stubs_start[], __stubs_end[];

extern char __vectors_start[], __vectors_end[];

extern char __kuser_helper_start[], __kuser_helper_end[];

int kuser_sz = __kuser_helper_end - __kuser_helper_start;

/*

* Copy the vectors, stubs and kuser helpers (in entry-armv.S)

* into the vector page, mapped at 0xffff0000, and ensure these

* are visible to the instruction stream.

*/

/*__vectors_end至__vectors_start之间为异常向量表。__stubs_end至__stubs_start之间是异常处理的位置。这些变量定义都在arch/arm/kernel/entry-armv.S中*/

memcpy((void *)vectors, __vectors_start, __vectors_end - __vectors_start);

memcpy((void *)vectors + 0x200, __stubs_start, __stubs_end - __stubs_start);

memcpy((void *)vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);

/*

* Do processor specific fixups for the kuser helpers

*/

kuser_get_tls_init(vectors);

/*

* Copy signal return handlers into the vector page, and

* set sigreturn to be a pointer to these.

*/

memcpy((void *)(vectors + KERN_SIGRETURN_CODE - CONFIG_VECTORS_BASE),

sigreturn_codes, sizeof(sigreturn_codes));

memcpy((void *)(vectors + KERN_RESTART_CODE - CONFIG_VECTORS_BASE),

syscall_restart_code, sizeof(syscall_restart_code));

flush_icache_range(vectors, vectors + PAGE_SIZE);

modify_domain(DOMAIN_USER, DOMAIN_CLIENT);

}

arch/arm/kernel/entry-armv.S

.globl__vectors_start

__vectors_start:

ARM( swi SYS_ERROR0 )

THUMB( svc #0 )

THUMB( nop )

W(b) vector_und + stubs_offset

W(ldr) pc, .LCvswi + stubs_offset

W(b) vector_pabt + stubs_offset

W(b) vector_dabt + stubs_offset

W(b) vector_addrexcptn + stubs_offset

W(b) vector_irq + stubs_offset

W(b) vector_fiq + stubs_offset

.globl__vectors_end

.globl__stubs_start