From 55149d06534ae2a7ba5f7a078353deb89b3fe891 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2017 00:05:04 -0600 Subject: objtool, compiler.h: Fix __unreachable section relocation size Linus reported the following commit broke module loading on his laptop: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends") It showed errors like the following: module: overflow in relocation type 10 val ffffffffc02afc81 module: 'nvme' likely not compiled with -mcmodel=kernel The problem is that the __unreachable section addresses are stored using the '.long' asm directive, which isn't big enough for .text section kernel addresses. Use relative addresses instead: ".long %c0b - .\t\n" Suggested-by: Linus Torvalds Reported-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Cc: Peter Zijlstra Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends") Link: http://lkml.kernel.org/r/20170301060504.oltm3iws6fmubnom@treble Signed-off-by: Ingo Molnar --- include/linux/compiler-gcc.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index 76e28c229805..b6bb9019d87f 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -201,7 +201,7 @@ #define annotate_unreachable() ({ \ asm("%c0:\t\n" \ ".pushsection __unreachable, \"a\"\t\n" \ - ".long %c0b\t\n" \ + ".long %c0b - .\t\n" \ ".popsection\t\n" : : "i" (__LINE__)); \ }) #else -- cgit v1.2.1 From e390f9a9689a42f477a6073e2e7df530a4c1b740 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Wed, 1 Mar 2017 12:04:44 -0600 Subject: objtool, modules: Discard objtool annotation sections for modules The '__unreachable' and '__func_stack_frame_non_standard' sections are only used at compile time. They're discarded for vmlinux but they should also be discarded for modules. Since this is a recurring pattern, prefix the section names with ".discard.". It's a nice convention and vmlinux.lds.h already discards such sections. Also remove the 'a' (allocatable) flag from the __unreachable section since it doesn't make sense for a discarded section. Suggested-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Cc: Jessica Yu Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends") Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble Signed-off-by: Ingo Molnar --- include/linux/compiler-gcc.h | 2 +- include/linux/frame.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h index b6bb9019d87f..0efef9cf014f 100644 --- a/include/linux/compiler-gcc.h +++ b/include/linux/compiler-gcc.h @@ -200,7 +200,7 @@ #ifdef CONFIG_STACK_VALIDATION #define annotate_unreachable() ({ \ asm("%c0:\t\n" \ - ".pushsection __unreachable, \"a\"\t\n" \ + ".pushsection .discard.unreachable\t\n" \ ".long %c0b - .\t\n" \ ".popsection\t\n" : : "i" (__LINE__)); \ }) 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 */ -- cgit v1.2.1