Linux异常体系之vector

ARM-Linux汇编的宏定义语法说明如下：

使用注意：

1.宏定义以.macro开始，以.endm结束

2.可带参数，参数可有默认值

3.直接使用参数的名字\arg

vector_stub宏的功能：

计算处理完异常的返回地址；

保存寄存器(r0，lr，spsr)

进入管理模式；

最后根据进入异常前的模式跳转到相应的某个分支。

 /*

  * Vector stubs.

  *

  * This code is copied to 0xffff0200 so we can use branches in the

  * vectors, rather than ldr's.  Note that this code must not

  * exceed 0x300 bytes.

  *

  * Common stub entry macro:

  *   Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC

  *

  * SP points to a minimal amount of processor-private memory, the address

  * of which is copied into r0 for the mode specific abort handler.

  */

     .macro    vector_stub, name, mode, correction=

     .align    

 vector_\name:

     .if \correction

     sub    lr, lr, #\correction

     .endif

     @

     @ Save r0, lr_<exception> (parent PC) and spsr_<exception>

     @ (parent CPSR)

     @

     stmia    sp, {r0, lr}        @ save r0, lr

     mrs    lr, spsr

     str    lr, [sp, #]        @ save spsr

     @

     @ Prepare for SVC32 mode.  IRQs remain disabled.

     @

     mrs    r0, cpsr

     eor    r0, r0, #(\mode ^ SVC_MODE)

     msr    spsr_cxsf, r0

     @

     @ the branch table must immediately follow this code

     @

     and    lr, lr, #0x0f

     mov    r0, sp

     ldr    lr, [pc, lr, lsl #]

     movs    pc, lr            @ branch to handler in SVC mode

     .endm

展开

 /*

  * Interrupt dispatcher

  */

     vector_stub    irq, IRQ_MODE, 

     .long    __irq_usr            @    (USR_26 / USR_32)

     .long    __irq_invalid            @    (FIQ_26 / FIQ_32)

     .long    __irq_invalid            @    (IRQ_26 / IRQ_32)

     .long    __irq_svc            @    (SVC_26 / SVC_32)

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @  a

     .long    __irq_invalid            @  b

     .long    __irq_invalid            @  c

     .long    __irq_invalid            @  d

     .long    __irq_invalid            @  e

     .long    __irq_invalid            @  f

后得到

 /*

  * Interrupt dispatcher

  */

     .align    

 vector_irq:

     sub    lr, lr, #               //保存irq返回地址

     @

     @ Save r0, lr_<exception> (parent PC) and spsr_<exception>

     @ (parent CPSR)

     @

     stmia    sp, {r0, lr}        @ save r0, lr

     mrs    lr, spsr

     str    lr, [sp, #]        @ save spsr

     @

     @ Prepare for SVC32 mode.  IRQs remain disabled.

     @

     mrs    r0, cpsr

     eor    r0, r0, #(\mode ^ SVC_MODE)

     msr    spsr_cxsf, r0 //对spsr的所有控制位进行写操作,将r0的值全部注入spsr，进入svc模式

     @

     @ the branch table must immediately follow this code

     @

     and    lr, lr, #0x0f  //根据进入中断前的模式跳转到相应的中断处理函数

     mov    r0, sp

     ldr    lr, [pc, lr, lsl #]

     movs    pc, lr            @ branch to handler in SVC mode

     .long    __irq_usr            @    (USR_26 / USR_32)

     .long    __irq_invalid            @    (FIQ_26 / FIQ_32)

     .long    __irq_invalid            @    (IRQ_26 / IRQ_32)

     .long    __irq_svc            @    (SVC_26 / SVC_32)

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @

     .long    __irq_invalid            @  a

     .long    __irq_invalid            @  b

     .long    __irq_invalid            @  c

     .long    __irq_invalid            @  d

     .long    __irq_invalid            @  e

     .long    __irq_invalid            @  f

巴特西

Linux异常体系之vector_stub宏解析

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