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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-07 12:02:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-07 12:02:24 -0700
commitddc4e6d232d6b625a5686ec1aafe42b9e0109a4c (patch)
tree53f865760ca450fdb1789377516053980d96a837 /arch
parentbc75450cc3db3485db1e289fef8c1028ba38296a (diff)
parent2992ef29ae01af998399d55ed7c692a2505fb8af (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching
Pull livepatching updates from Jiri Kosina: - fix for patching modules that contain .altinstructions or .parainstructions sections, from Jessica Yu - make TAINT_LIVEPATCH a per-module flag (so that it's immediately clear which module caused the taint), from Josh Poimboeuf * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching: livepatch/module: make TAINT_LIVEPATCH module-specific Documentation: livepatch: add section about arch-specific code livepatch/x86: apply alternatives and paravirt patches after relocations livepatch: use arch_klp_init_object_loaded() to finish arch-specific tasks
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/Makefile1
-rw-r--r--arch/x86/kernel/livepatch.c65
2 files changed, 66 insertions, 0 deletions
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 45257cf84370..4dd5d500eb60 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -83,6 +83,7 @@ obj-$(CONFIG_X86_MPPARSE) += mpparse.o
obj-y += apic/
obj-$(CONFIG_X86_REBOOTFIXUPS) += reboot_fixups_32.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
+obj-$(CONFIG_LIVEPATCH) += livepatch.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o
obj-$(CONFIG_X86_TSC) += trace_clock.o
diff --git a/arch/x86/kernel/livepatch.c b/arch/x86/kernel/livepatch.c
new file mode 100644
index 000000000000..e9d252d873aa
--- /dev/null
+++ b/arch/x86/kernel/livepatch.c
@@ -0,0 +1,65 @@
+/*
+ * livepatch.c - x86-specific Kernel Live Patching Core
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/livepatch.h>
+#include <asm/text-patching.h>
+
+/* Apply per-object alternatives. Based on x86 module_finalize() */
+void arch_klp_init_object_loaded(struct klp_patch *patch,
+ struct klp_object *obj)
+{
+ int cnt;
+ struct klp_modinfo *info;
+ Elf_Shdr *s, *alt = NULL, *para = NULL;
+ void *aseg, *pseg;
+ const char *objname;
+ char sec_objname[MODULE_NAME_LEN];
+ char secname[KSYM_NAME_LEN];
+
+ info = patch->mod->klp_info;
+ objname = obj->name ? obj->name : "vmlinux";
+
+ /* See livepatch core code for BUILD_BUG_ON() explanation */
+ BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
+
+ for (s = info->sechdrs; s < info->sechdrs + info->hdr.e_shnum; s++) {
+ /* Apply per-object .klp.arch sections */
+ cnt = sscanf(info->secstrings + s->sh_name,
+ ".klp.arch.%55[^.].%127s",
+ sec_objname, secname);
+ if (cnt != 2)
+ continue;
+ if (strcmp(sec_objname, objname))
+ continue;
+ if (!strcmp(".altinstructions", secname))
+ alt = s;
+ if (!strcmp(".parainstructions", secname))
+ para = s;
+ }
+
+ if (alt) {
+ aseg = (void *) alt->sh_addr;
+ apply_alternatives(aseg, aseg + alt->sh_size);
+ }
+
+ if (para) {
+ pseg = (void *) para->sh_addr;
+ apply_paravirt(pseg, pseg + para->sh_size);
+ }
+}