[haiku-development] Question on the arch_cpu_user_memcpy function
- From: David McPaul <dlmcpaul@xxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Fri, 2 Oct 2009 11:06:57 +1000
Hello,
I am tracing through an issue I am having when using the profile tool
to profile media add-ons
I get a General Protection Fault code 0x0 in the arch_cpu_user_memcpy
function when the profiler is trying to get the frame stack details
The registers printed in the error stack trace show that the src ptr is NULL
My reading of the code suggests that the error should be trapped and
-1 returned by the function.
Am I wrong here, does the fault handler added not handle a null pointer?
FUNCTION(arch_cpu_user_memcpy):
pushl %esi
pushl %edi
movl 12(%esp),%edi /* dest */
movl 16(%esp),%esi /* source */
movl 20(%esp),%ecx /* count */
/* set the fault handler */
movl 24(%esp),%edx /* fault handler */
movl (%edx),%eax
movl $.L_user_memcpy_error, (%edx)
/* move by words */
cld
shrl $2,%ecx
rep
movsl
/* move any remaining data by bytes */
movl 20(%esp),%ecx
andl $3,%ecx
rep
movsb
/* restore the old fault handler */
movl %eax,(%edx)
xor %eax,%eax
popl %edi
popl %esi
ret
/* error condition */
.L_user_memcpy_error:
/* restore the old fault handler */
movl %eax,(%edx)
movl $-1,%eax /* return a generic error, the wrapper routine
will
deal with it */
popl %edi
popl %esi
ret
FUNCTION_END(arch_cpu_user_memcpy)
--
Cheers
David
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