Re: [seL4] sel4test data abort when boot strap test program

Hi Joyce,

On 09/05/17 17:15, Joyce Peng(彭美僑) wrote:

Hi all,

I tried to run seL4 test suite on my ARM Cortex-A7 target board.

What is the name of the board you have? How do you build and run sel4test?

There is no error message when boot up seL4 kernel and boot strap test program on seL4 user land.

But I got a “data abort” message after call sel4utils_map_page(..vaddr) and do memset(vaddr, 0, PAGE_SIZE_4K);

There are some debug information list below.

<1> I add debug message before the program that happen data abort

diff --git a/libsel4utils/src/vspace/bootstrap.c b/libsel4utils/src/vspace/bootstrap.c

index c366a35..70d378a 100644

--- a/libsel4utils/src/vspace/bootstrap.c

+++ b/libsel4utils/src/vspace/bootstrap.c

@@ -107,13 +107,13 @@ static void *alloc_and_map(vspace_t *vspace, size_t size) {

         error = sel4utils_map_page(data->vka, data->vspace_root, 

frame.cptr, vaddr,

seL4_AllRights, 1, objects, &num);

• LOG_ERROR("my-hacker\n");

         if (error) {
  
  

vka_free_object(data->vka, &frame);

LOG_ERROR("Failed to map bootstrap frame at %p, error: %d", vaddr, error);

             return NULL;

         }

• LOG_ERROR("my-hacker alloc_and_map() before memset vaddr=0x%x\n",vaddr);

         /* Zero the memory */
  
  

memset(vaddr, 0, PAGE_SIZE_4K);

<2>Printed messages:

ELF-loader started on CPU: ARM Ltd. Cortex-A7 r0p5

paddr=[20000000..2051881f]

ELF-loading image 'kernel'

paddr=[22000000..22032fff]

vaddr=[e0000000..e0032fff]

virt_entry=e0000000

ELF-loading image 'sel4test-driver'

paddr=[22033000..22463fff]

vaddr=[8000..438fff]

virt_entry=15f50

Enabling MMU and paging

Jumping to kernel-image entry point...

Bootstrapping kernel

Booting all finished, dropped to user space

Warning: using printf before serial is set up. This only works as your

printf is backed by seL4_Debug_PutChar()

alloc_and_map@bootstrap.c:111 my-hacker

alloc_and_map@bootstrap.c:119 my-hacker alloc_and_map() before memset() vaddr=0xdf7fe000

<3>When happen data abort, the value of CPU registers:

r1:0

r3:0xdf7fe000

lr:0xcbe8

<4>Objdump sel4test-driver.

0000cbc8 <memset>:

cbc8:       e3520000        cmp     r2, #0

cbcc: e92d4030        push    {r4, r5, lr}

cbd0: 08bd8030        popeq   {r4, r5, pc}

cbd4: e0803002        add     r3, r0, r2

cbd8: e6ef1071        uxtb    r1, r1

cbdc: e3520002        cmp     r2, #2

cbe0: e5431001 strb r1, [r3, #-1]

cbe4: e5c01000        strb    r1, [r0]

cbe8: 98bd8030        popls   {r4, r5, pc}

cbec: e3520006        cmp     r2, #6

It seems to write virtual address 0xdf7ff000.

<5>The virtual address 0xdf7fe000 is not map in page table

It seems sel4utils_map_page() not create page table for user land program correctly.

Can anyonehelp me, how to solve this problem? Thanks!

Joyce Peng(彭美僑)

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Cheers, Hesham