Messages in this thread | | | Date | Tue, 21 Sep 2010 11:58:56 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 03/10] jump label v11: base patch |
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On 09/21/2010 11:55 AM, Konrad Rzeszutek Wilk wrote: >>> +early_initcall(init_jump_label); >> >> Is there any danger of not patching the instructions with NOPs before >> early_initcall is called? I guess for your uses (tracing) there won't. >> And even if there are not patched it will just call the function. > > Ah, nevermind - if you don't patch the addresses which are in > _jump_label section, the untouched code will just do far jump (jmpq) > to right after the macro, which is ok.
Technical point of order: jmpq is *NOT* a far jump. A far jump (called ljmp in gas) is a completely different x86 instruction with *very* different semantics.
-hpa
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