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A question about backport jump label

DISCUSSION Li Yu 1 participant 1 message Apr 11, 2012

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Li Yu

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Hi,

We want to backport jump label for 2.6.32 x86_64 kernel on
RHEL5/RHEL6. Such two systems use old versions of gcc 4.1 and 4.4, so they have not "asm goto" support, which is required for jump label.

I tried some ways to implement jump label without any
modification of core implementation, but all are failed.

My tries are focus on x86's arch_static_branch() modification.
So far, I don't found out any good alternative solution of "asm goto" in old gcc. The last try is failed since its my implementation can't be invoked at same function multi times. The reason is GNU as does not assign different addresses on same symbol.

My question, is possible to implement to jump label under such
constraints? It's best to keep same interface with upstream tree.

Any suggestions is welcome, thanks.

Yu