线程 ppc_PowerPC

启动线程转到system_call的故障

发布于 2021-09-14 11:05:18 浏览：988 订阅该版

1 个回答

出出啊 2021-09-14

恃人不如自恃，人之为己者不如己之自为也

derekjoon 2021-09-14

Remember for give, for get, for given.

去了`static void System_Call(void)`，此函数原本是`{COND_TRAP(31,0,0);}`
我改成：`{rt_hw_systemcall_entry();}`，然后进了`Unalign_Access()`，死了。

```asm
rt_hw_systemcall_entry:
    mtspr   SPRG0,r3                            /* save r3 to SPRG0 */
    mtspr   SPRG1,r4                            /* save r4 to SPRG1 */

lis     r3,rt_thread_switch_interrput_flag@h
    ori     r3,r3,rt_thread_switch_interrput_flag@l
    lwz     r4,0(r3)
    cmpi    cr0,0,r4,0x0                        /* whether is 0     */
    beq     _no_switch                          /* no switch, exit  */
    li      r4,0x0                              /* set rt_thread_switch_interrput_flag to 0 */
    stw     r4,0(r3)

/* load from thread to r3 */
    lis     r3,rt_interrupt_from_thread@h       /* set rt_interrupt_from_thread */
    ori     r3,r3,rt_interrupt_from_thread@l
    lwz     r3,0(r3)

cmpi    cr0,0,r3,0x0                        /* whether is 0 */
    beq     _restore                            /* it's first switch, goto _restore */

/* save r1:sp to thread[from] stack pointer */
    subi    r1, r1, STACK_FRAME_SIZE
    stw     r1, 0(r3)

/* restore r3, r4 from SPRG */
    mfspr   r3,SPRG0
    mfspr   r4,SPRG0

/* save registers   */
    stw     r0,GPR0(r1)                         /* save general purpose registers 0    */
    stmw    r2,GPR2(r1)                         /* save general purpose registers 2-31 */

mfusprg0 r0                                 /* save usprg0  */
    stw     r0,USPRG0(r1)
    mfcr    r0,                                 /* save cr      */
    stw     r0,CR(r1)
    mfxer   r0                                  /* save xer     */
    stw     r0,XER(r1)
    mfctr   r0                                  /* save ctr     */
    stw     r0,CTR(r1)
    mflr    r0                                  /* save lr      */
    stw     r0, LR(r1)

mfsrr0  r0                                  /* save SRR0 and SRR1   */
    stw     r0,SRR0(r1)
    mfsrr1  r0
    stw     r0,SRR1(r1)
```

```asm
_restore:
    /* get thread[to] stack pointer */
    lis     r4,rt_interrupt_to_thread@h
    ori     r4,r4,rt_interrupt_to_thread@l
    lwz     r1,0(r4)
    lwz     r1,0(r1)

lwz     r0,SRR1(r1)                         /* restore SRR1 and SRR0   */
    mtsrr1  r0
    lwz     r0,SRR0(r1)
    mtsrr0  r0

lwz     r0,LR(r1)                           /* restore lr       */
    mtlr    r0
    lwz     r0,CTR(r1)                          /* restore ctr     */
    mtctr   r0
    lwz     r0,XER(r1)                          /* restore xer     */
    mtxer   r0
    lwz     r0,CR(r1)                           /* restore cr      */
    mtcr    r0
    lwz     r0,USPRG0(r1)                       /* restore usprg0  */
    // mtusprg0 r0

lmw     r2, GPR2(r1)                        /* restore general register */
    lwz     r0,GPR0(r1)
    addi    r1, r1, STACK_FRAME_SIZE
    /* RFI will restore status register and thus the correct priority*/
    rfi
```

```asm
_no_switch:
    /* restore r3, r4 from SPRG */
    mfspr   r3,SPRG0
    mfspr   r4,SPRG0
    rfi
```