Re: Machine check exception. 2.6.20 powerpc tree.

On Jul 17, 2007, at 9:21 AM, Ramirez-Ortiz, Jorge wrote:

Running our multithreaded application on ppc8548 (E500 core) =20
generates a machine check exception when trying to access some =20
ASIC=92s registers mapped on the PCI space (This application maps a =20=

PCI device to access its registers)



machine_check_exception: task my_process, MCSR=3D0x10008, =

NIP=3D0x10153530

Machine check in user mode.

Caused by (from MCSR=3D10008): Guarded Load or Cache-Inhibited stwcx.

Bus - Read Data Bus Error



Here is the assembly dump of the region of code containing the =20
offending instruction in user-space, with SRR0 pointing us at =20
0x10153530 when the exception is raised:



0x10153528 <_ZN2vk7in_le32EPVKj+16>:    lwz     r0,8(r31)

0x1015352c <_ZN2vk7in_le32EPVKj+20>:    lwz     r9,8(r31)

0x10153530 <_ZN2vk7in_le32EPVKj+24>:    lwbrx   r0,0,r0

0x10153534 <_ZN2vk7in_le32EPVKj+28>:    twi     0,r0,0

0x10153538 <_ZN2vk7in_le32EPVKj+32>:    isync

Can you get the code to dump the value of r0.  I'm wondering if =20
you're really getting a read data bus error due to the fact that r0 =20
is pointing to a PCI address that doesn't have a device that will =20
respond.

- k