請教個ARM的Kernel panic的pc指針問題

fire_vr

看過很多資料，說Arm Kernel在panic或者oops錯誤時，由于流水線的關(guān)系，實際運行指令是打印出來的PC指針減去8。

但我自己做個簡單的模塊試試，看上去，PC指針指向的就是代碼錯誤的地方，不需要減去8呀。
請高手指教，謝謝！
我的Kernel是3.4，ARM A5架構(gòu)。

1. int msm_hello_init(void)
   
2. {
   
3.         char *testptr = 0x98;
   
4.        
   
5.         printk("111Hello Cruel World wewewe!\n");
   
6.          
   
7.         *testptr = 0x1234;
   
8.    
   
9.         return 0;
   
10. }
    

復(fù)制代碼

Kernel反匯編的相關(guān)代碼為：

1. c001f114 <msm_hello_init>:
   
2. c001f114:        e1a0c00d         mov        ip, sp
   
3. c001f118:        e92dd800         push        {fp, ip, lr, pc}
   
4. c001f11c:        e24cb004         sub        fp, ip, #4
   
5. c001f120:        e52de004         push        {lr}                ; (str lr, [sp, #-4]!)
   
6. c001f124:        ebffbd9f         bl        c000e7a8 <__gnu_mcount_nc>
   
7. c001f128:        e59f0010         ldr        r0, [pc, #16]        ; c001f140 <msm_hello_init+0x2c>
   
8. c001f12c:        eb188804         bl        c0641144 <printk>
   
9. c001f130:        e3a00000         mov        r0, #0
   
10. c001f134:        e3a03034         mov        r3, #52        ; 0x34
    
11. c001f138:        e5c03098         strb        r3, [r0, #152]        ; 0x98
    
12. c001f13c:        e89da800         ldm        sp, {fp, sp, pc}
    
13. c001f140:        c077f0b0         .word        0xc077f0b0
    

復(fù)制代碼

打印出來的panic是：
[    2.861010] Internal error: Oops: 805 [#1] PREEMPT ARM
[    2.866107] Modules linked in:
[    2.869159] CPU: 0    Not tainted  (3.4.91-a91ac065df_d3ff0ee36f #1)
[    2.875507] PC is at msm_hello_init+0x24/0x30
[    2.879841] LR is at console_unlock+0x25c/0x274
[    2.884358] pc : [<c001f138>]    lr : [<c005d644>]    psr: 60000013
[    2.884358] sp : cf033f28  ip : cf033e40  fp : cf033f34
[    2.895803] r10: c001f114  r9 : 00000000  r8 : 00000119
[    2.900991] r7 : c09e5000  r6 : c09480c0  r5 : c0927a38  r4 : 00000007
[    2.907523] r3 : 00000034  r2 : c096dc80  r1 : 00000000  r0 : 00000000
[    2.914024] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
[    2.921318] Control: 10c5387d  Table: 40804059  DAC: 00000015
[    2.927056] Process swapper (pid: 1, stack limit = 0xcf0322e
[    2.932855] Stack: (0xcf033f28 to 0xcf034000)
[    2.937219] 3f20:                   cf033f74 cf033f38 c00085f0 c001f120 00000007 00000007
[    2.945368] 3f40: 00000119 c08720d4 cf033f74 00000007 c0927a38 c09480c0 c09e5000 00000119
[    2.953547] 3f60: 00000000 c0927a40 cf033ff4 cf033f78 c08f99b0 c0008558 00000007 00000007
[    2.961696] 3f80: c08f9268 00000000 cf033fac cf033f98 c00891e0 c0088dac 00000000 00000000
[    2.969845] 3fa0: 00000000 cf033fb0 c000e734 c00891d4 00000000 00000000 00000000 00000000
[    2.978025] 3fc0: 00000000 c08f986c c000f770 00000013 00000000 c08f986c c000f770 00000013
[    2.986174] 3fe0: 00000000 00000000 00000000 cf033ff8 c000f770 c08f9878 9dcfdd76 de7fffb4
[    2.994353] [<c001f138>] (msm_hello_init+0x24/0x30) from [<c00085f0>] (do_one_initcall+0xa4/0x174)
[    3.003296] [<c00085f0>] (do_one_initcall+0xa4/0x174) from [<c08f99b0>] (kernel_init+0x144/0x234)
[    3.012147] [<c08f99b0>] (kernel_init+0x144/0x234) from [<c000f770>] (kernel_thread_exit+0x0/0x
[    3.020967] Code: e59f0010 eb188804 e3a00000 e3a03034 (e5c0309
[    3.027132] ---[ end trace 44db375dc1d37124 ]---
[    3.031710] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

fire_vr

ding.........