Zola Bridges los ntawm Google rau LLVM compiler teeb, ib thaj nrog kev siv ntawm SESES (Speculative Execution Side Effect Suppression) kev tiv thaiv, uas pab thaiv kev tawm tsam ntawm kev xav txog kev ua tiav hauv Intel CPUs, xws li . Txoj kev tiv thaiv yog siv nyob rau theem compiler thiab yog raws li kev ntxiv cov lus qhia los ntawm compiler thaum tsim tshuab code , uas tau muab tso ua ntej txhua lub cim xeeb nyeem lossis sau cov lus qhia, nrog rau ua ntej thawj ceg qhia hauv pawg lus qhia uas xaus qhov thaiv.
LFENCE cov lus qhia tos rau tag nrho cov cim xeeb yav dhau los nyeem kom ua txhaum thiab tsis ua haujlwm preemption ntawm cov lus qhia tom ntej tom qab LFENCE kom txog thaum qhov kev cog lus tiav. Kev siv LFENCE ua rau muaj kev poob qis hauv kev ua haujlwm, yog li kev tiv thaiv yog npaj los siv rau hauv cov xwm txheej hnyav rau cov cai tshwj xeeb. Ntxiv nrog rau kev tiv thaiv tag nrho, lub thaj muaj peb tus chij uas tso cai rau koj xaiv lov tes taw qee qhov kev tiv thaiv kom txo tau qhov tsis zoo ntawm kev ua haujlwm.
Hauv kev sim ua, kev siv SESES kev tiv thaiv rau pob BoringSSL tau ua rau txo qis ntawm cov haujlwm hauv ib lub thib ob uas tau ua los ntawm lub tsev qiv ntawv los ntawm 14 zaug - qhov kev ua tau zoo ntawm kev tiv thaiv ntawm lub tsev qiv ntawv yog qhov nruab nrab tsuas yog 7.1% ntawm cov unprotected version (variation nyob ntawm qhov kev xeem los ntawm 4% mus rau 23%).
Rau kev sib piv, Yav dhau los, rau GNU Assembler, lub tshuab ua haujlwm LFENCE hloov pauv tom qab txhua lub cim xeeb thauj khoom thiab ua ntej qee cov lus qhia ntawm ceg tau pom qhov ua tau zoo ntawm 5 zaug (22% ntawm cov cai tsis muaj kev tiv thaiv). Txoj kev tiv thaiv kuj yog ΠΈ los ntawm Intel engineers, tab sis cov txiaj ntsig kev xeem rau nws tseem tsis tau luam tawm. Thaum pib, cov kws tshawb fawb uas tau txheeb xyuas qhov kev tawm tsam LVI tau kwv yees 2- txog 19-fold txo qis hauv kev ua haujlwm thaum siv kev tiv thaiv tag nrho.
Tau qhov twg los: opennet.ru