On 03/06/2013 09:29 AM, Jens Rottmann wrote:
Hi Martin (and all),
I wrote:
You dereference dev in line 132, so if it's really 0, will you then ever reach this check?? (I don't know if in romstage *NULL is caught.)
You wrote:
yes, if it's 0, we still reach the code. I've changed it to not dereference it before checking it though.
Per default, after any *ptr, GCC assumes a SEGFAULT would occur if ptr was ==0, so if control flow does reach the following code ptr must be !=0. ==> After any *ptr GCC will optimize away all ptr==0 or !=0 checks. I know that because I recently hunted a related bug for a week (U-Boot, ARM, different project) until I looked at the actual assembly code.
Are you sure romstage (or maybe even ramstage?) will *NULL without segfaulting and just continue? And is romstage compiled with GCC (+ CAR) or is romcc used?
In that case "-fno-delete-null-pointer-checks" must be added to the GCC options. http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
I greped a bit, looks like it's not in any Makefiles yet.
Could someone who knows Coreboot's make/build system better than me maybe help, please?
Thanks Jens
Jens, I'm pretty sure, but I'm not *COMPLETELY* positive about this. I had to add this check because I kept getting null pointers due to an issue with the unterminated #pragma pack(1) in the porting.h file - that was messing my pointers up pretty badly. I'll work on checking this issue directly and respond back with what I find out. Martin