Porting vrouter.ko to powerPC platform

[Dineshkumarparameswaran]

I am porting vrouter-agent to powerpc platform.While compiling the kernel module i am getting following warnings. While inserting the kernel module it throws the same error.

WARNING: "__sync_fetch_and_add_8" undefined
WARNING: "__sync_sub_and_fetch_8" undefined

Can anyone please comment on this

[pedro-r-marques]

Dinesh,
The dev mailing list (http://lists.opencontrail.org/mailman/listinfo/dev_lists.opencontrail.org) would be a better way to get help... if i recall correctly _sync_fetch_and_add are symbols for atomic instructions on x86. You will have to search for the equivalents in the architecture you are using.

[srajag]

From https://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Atomic-Builtins.html

"Not all operations are supported by all target processors. If a particular operation cannot be implemented on the target processor, a warning will be generated and a call an external function will be generated. The external function will carry the same name as the builtin, with an additional suffix `_n' where n is the size of the data type."

Looks like ppc is not supported by gcc for these atomic builtins.

[VigneshwaranRM]

Hi,

Where the definition of these two files, __sync_fetch_and_add and __sync_sub_and_fetch.. It is not present with the contrail-agent source code. If so it will in the kernel source code ??

[srajag]

Those are compiler built-ins i.e. gcc implements them.

[VigneshwaranRM]

So, we will not have any definition for this functions ??

[srajag]

yes

[VigneshwaranRM]

What I thought was, to see the definition of the function and change accordingly to support ppc.. If that is not possible, what could be the solution??

I saw in a forum like, by replacing _sync_fetch to _atomic will solve this problem, will this work ??

or any other solution you know ?? If so please help

[srajag]

You can add an ifdef for PPC and add equivalent code.

[VigneshwaranRM]

ok let me try. thanks