{"id":2207,"date":"2018-02-01T09:06:06","date_gmt":"2018-02-01T17:06:06","guid":{"rendered":"http:\/\/rglinuxtech.com\/?p=2207"},"modified":"2018-02-01T09:06:06","modified_gmt":"2018-02-01T17:06:06","slug":"kernel-gcc-and-retpoline","status":"publish","type":"post","link":"https:\/\/rglinuxtech.com\/?p=2207","title":{"rendered":"Kernel &#8211; GCC and &#8216;Retpoline&#8217;.."},"content":{"rendered":"<p>The recent summary of Kernel 4.15 mentioned the test for &#8216;compliant&#8217; versions of GCC which fully support the <em>retpoline<\/em> mitigation, but only gave an example of non-compliance:<\/p>\n<p>With GCC 7.2:<\/p>\n<p><code><strong><span style=\"font-family: courier\\ new, courier;\">~]$ cat \/sys\/devices\/system\/cpu\/vulnerabilities\/spectre_v2<\/span><\/strong><br \/>\n<strong><span style=\"font-family: courier\\ new, courier;\">\u00a0Vulnerable: Minimal generic ASM retpoline<\/span><\/strong><\/code><\/p>\n<p>I re-created Fedora (<em>Rawhide<\/em>) GCC <strong>7.3.1<\/strong> for Fedora 27, and it gives the following, after Kernel 4.15 compilation\/boot:<\/p>\n<p><code><strong><span style=\"font-family: courier\\ new, courier;\">~]$ cat \/sys\/devices\/system\/cpu\/vulnerabilities\/spectre_v2<\/span><\/strong><br \/>\n<strong><span style=\"font-family: courier\\ new, courier;\">\u00a0Mitigation: Full generic retpoline<\/span><\/strong><\/code><\/p>\n<p>GCC 7.3.x should be available for Fedora 27 and other Distros, soon..<\/p>\n<p><em>Robert Gadsdon.\u00a0 February 1, 2018.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The recent summary of Kernel 4.15 mentioned the test for &#8216;compliant&#8217; versions of GCC which fully support the retpoline mitigation, but only gave an example of non-compliance: With GCC 7.2: ~]$ cat \/sys\/devices\/system\/cpu\/vulnerabilities\/spectre_v2 \u00a0Vulnerable: Minimal generic ASM retpoline I re-created Fedora (Rawhide) GCC 7.3.1 for Fedora 27, and it gives the following, after Kernel 4.15 compilation\/boot: ~]$ <span class=\"excerpt-dots\">&hellip;<\/span> <a class=\"more-link\" href=\"https:\/\/rglinuxtech.com\/?p=2207\"><span class=\"more-msg\">Continue reading &rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[5,1617,1323,14,15,20,1813],"tags":[1816,1817,1042,1173,242,1815,1810,1814],"class_list":["post-2207","post","type-post","status-publish","format-standard","hentry","category-compilation","category-gcc","category-intel","category-kernel","category-linux-2","category-performance-2","category-retpoline","tag-7-3-1","tag-backport","tag-gcc","tag-kernel","tag-linux","tag-mitigation","tag-retpoline","tag-spectre2"],"_links":{"self":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/2207","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2207"}],"version-history":[{"count":2,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/2207\/revisions"}],"predecessor-version":[{"id":2209,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=\/wp\/v2\/posts\/2207\/revisions\/2209"}],"wp:attachment":[{"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2207"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2207"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rglinuxtech.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2207"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}