On 20/11/2019 16:40, Jürgen Groß wrote: > On 20.11.19 17:30, Jan Beulich wrote: >> On 08.11.2019 12:18, Jan Beulich wrote: >>> The .file assembler directives generated by the compiler do not include >>> any path components (gcc) or just the ones specified on the command >>> line >>> (clang, at least version 5), and hence multiple identically named >>> source >>> files (in different directories) may produce identically named static >>> symbols (in their kallsyms representation). The binary diffing >>> algorithm >>> used by xen-livepatch, however, depends on having unique symbols. >>> >>> Make the ENFORCE_UNIQUE_SYMBOLS Kconfig option control the (build) >>> behavior, and if enabled use objcopy to prepend the (relative to the >>> xen/ subdirectory) path to the compiler invoked STT_FILE symbols. Note >>> that this build option is made no longer depend on LIVEPATCH, but >>> merely >>> defaults to its setting now. >>> >>> Conditionalize explicit .file directive insertion in C files where it >>> exists just to disambiguate names in a less generic manner; note that >>> at the same time the redundant emission of STT_FILE symbols gets >>> suppressed for clang. Assembler files as well as multiply compiled C >>> ones using __OBJECT_FILE__ are left alone for the time being. >>> >>> Since we now expect there not to be any duplicates anymore, also don't >>> force the selection of the option to 'n' anymore in allrandom.config. >>> Similarly COVERAGE no longer suppresses duplicate symbol warnings if >>> enforcement is in effect, which in turn allows >>> SUPPRESS_DUPLICATE_SYMBOL_WARNINGS to simply depend on >>> !ENFORCE_UNIQUE_SYMBOLS. >>> >>> Signed-off-by: Jan Beulich <jbeul...@suse.com> >> >> I've got acks from Konrad and Wei, but still need an x86 and a release >> one here. Andrew? Or alternatively - Jürgen, would you rather not see >> this go in anymore? > > In case the needed x86 Ack is coming in before RC3 I'm fine to give my > Release-ack, but I'm hesitant to take it later.
Has anyone actually tried building a livepatch with this change in place? I ask, because there is 0 testing of livepatches, and already one major regression in 4.13 which forces XenServer to revert back to older build tools. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
