[GIT PULL] objtool fixes

From: Ingo Molnar
Date: Wed Mar 01 2017 - 17:09:35 EST


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(-)

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index ad0118fbce90..c74ae9ce8dc4 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -345,8 +345,6 @@ SECTIONS
DISCARDS
/DISCARD/ : {
*(.eh_frame)
- *(__func_stack_frame_non_standard)
- *(__unreachable)
}
}

diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 76e28c229805..0efef9cf014f 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -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
diff --git a/include/linux/frame.h b/include/linux/frame.h
index e6baaba3f1ae..d772c61c31da 100644
--- a/include/linux/frame.h
+++ b/include/linux/frame.h
@@ -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 */
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 4dedd0d3d3a7..30d752a4a6a6 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -854,6 +854,7 @@ static const char *const section_white_list[] =
".cmem*", /* EZchip */
".fmt_slot*", /* EZchip */
".gnu.lto*",
+ ".discard.*",
NULL
};

diff --git a/scripts/module-common.lds b/scripts/module-common.lds
index 73a2c7da0e55..cf7e52e4781b 100644
--- a/scripts/module-common.lds
+++ b/scripts/module-common.lds
@@ -4,7 +4,10 @@
* combine them automatically.
*/
SECTIONS {
- /DISCARD/ : { *(.discard) }
+ /DISCARD/ : {
+ *(.discard)
+ *(.discard.*)
+ }

__ksymtab 0 : { *(SORT(___ksymtab+*)) }
__ksymtab_gpl 0 : { *(SORT(___ksymtab_gpl+*)) }
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 5fc52ee3264c..4cfdbb5b6967 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -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");