objtool fixes

GIT PULL Ingo Molnar 1 participant 1 message Mar 1, 2017

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x86 Kbuild Module support objtool

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Ingo Molnar

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2017-03-01 22:09 UTC #0 lore raw

Linus,

Please pull the latest core-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git core-urgent-for-linus

# HEAD: e390f9a9689a42f477a6073e2e7df530a4c1b740 objtool, modules: Discard objtool annotation sections for modules

These two fixes related to the module loading regression introduced by the recent objtool changes.

Thanks,

Ingo

------------------>
Josh Poimboeuf (2):
objtool, compiler.h: Fix __unreachable section relocation size objtool, modules: Discard objtool annotation sections for modules

 arch/x86/kernel/vmlinux.lds.S | 2 --
 include/linux/compiler-gcc.h  | 4 ++--
 include/linux/frame.h         | 2 +-
 scripts/mod/modpost.c         | 1 +
 scripts/module-common.lds     | 5 ++++-
 tools/objtool/builtin-check.c | 6 +++---
 6 files changed, 11 insertions(+), 9 deletions(-)

arch/x86/kernel/vmlinux.lds.S +0 -2

index ad0118fbce90..c74ae9ce8dc4 100644
@@ -345,8 +345,6 @@ SECTIONS
 	DISCARDS
 	/DISCARD/ : {
 		*(.eh_frame)
-		*(__func_stack_frame_non_standard)
-		*(__unreachable)
 	}
 }

include/linux/compiler-gcc.h +2 -2

index 76e28c229805..0efef9cf014f 100644
@@ -200,8 +200,8 @@
 #ifdef CONFIG_STACK_VALIDATION
 #define annotate_unreachable() ({					\
 	asm("%c0:\t\n"							\
-	    ".pushsection __unreachable, \"a\"\t\n"			\
-	    ".long %c0b\t\n"						\
+	    ".pushsection .discard.unreachable\t\n"			\
+	    ".long %c0b - .\t\n"					\
 	    ".popsection\t\n" : : "i" (__LINE__));			\
 })
 #else

include/linux/frame.h +1 -1

index e6baaba3f1ae..d772c61c31da 100644
@@ -11,7 +11,7 @@
  * For more information, see tools/objtool/Documentation/stack-validation.txt.
  */
 #define STACK_FRAME_NON_STANDARD(func) \
-	static void __used __section(__func_stack_frame_non_standard) \
+	static void __used __section(.discard.func_stack_frame_non_standard) \
 		*__func_stack_frame_non_standard_##func = func
 
 #else /* !CONFIG_STACK_VALIDATION */

scripts/mod/modpost.c +1 -0

index 4dedd0d3d3a7..30d752a4a6a6 100644
@@ -854,6 +854,7 @@ static const char *const section_white_list[] =
 	".cmem*",			/* EZchip */
 	".fmt_slot*",			/* EZchip */
 	".gnu.lto*",
+	".discard.*",
 	NULL
 };

scripts/module-common.lds +4 -1

index 73a2c7da0e55..cf7e52e4781b 100644
@@ -4,7 +4,10 @@
  * combine them automatically.
  */
 SECTIONS {
-	/DISCARD/ : { *(.discard) }
+	/DISCARD/ : {
+		*(.discard)
+		*(.discard.*)
+	}
 
 	__ksymtab		0 : { *(SORT(___ksymtab+*)) }
 	__ksymtab_gpl		0 : { *(SORT(___ksymtab_gpl+*)) }

tools/objtool/builtin-check.c +3 -3

index 5fc52ee3264c..4cfdbb5b6967 100644
@@ -339,13 +339,13 @@ static int add_dead_ends(struct objtool_file *file)
 	struct instruction *insn;
 	bool found;
 
-	sec = find_section_by_name(file->elf, ".rela__unreachable");
+	sec = find_section_by_name(file->elf, ".rela.discard.unreachable");
 	if (!sec)
 		return 0;
 
 	list_for_each_entry(rela, &sec->rela_list, list) {
 		if (rela->sym->type != STT_SECTION) {
-			WARN("unexpected relocation symbol type in .rela__unreachable");
+			WARN("unexpected relocation symbol type in %s", sec->name);
 			return -1;
 		}
 		insn = find_insn(file, rela->sym->sec, rela->addend);

@@ -1272,7 +1272,7 @@ int cmd_check(int argc, const char **argv)
 
 	INIT_LIST_HEAD(&file.insn_list);
 	hash_init(file.insn_hash);
-	file.whitelist = find_section_by_name(file.elf, "__func_stack_frame_non_standard");
+	file.whitelist = find_section_by_name(file.elf, ".discard.func_stack_frame_non_standard");
 	file.rodata = find_section_by_name(file.elf, ".rodata");
 	file.ignore_unreachables = false;
 	file.c_file = find_section_by_name(file.elf, ".comment");