On Fri, Jun 12, 2015 at 05:00:50PM +0100, Pedro Alves wrote: > On 06/12/2015 03:10 PM, Josh Poimboeuf wrote: > > That said, the kernel has much more custom features than other projects. > > There are some sneaky macros, like _ASM_EXTABLE and ALTERNATIVE, which > > hide code in various sections. Unless we're able to somehow either stop > > using these macros or isolate them to a few places, I doubt that such a > > general purpose assembler option would work. > > How does the asmvalidator handle these? They're not easy to deal with... The ALTERNATIVE macro creates some instructions which can be patched in at runtime, to replace some original instructions, if the CPU supports certain features. So we have to look up those replacement instructions in another section and consider them to be potentially part of the original function when doing the analysis and generation. The _ASM_EXTABLE macro creates code which is executed after an exception. Similarly to the ALTERNATIVE macro, we have to look up those instructions and consider them to be part of the original function. -- Josh -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
