Messages in this thread Patch in this message | | | Date | Tue, 26 May 2009 06:09:50 GMT | From | tip-bot for Tejun Heo <> | Subject | [tip:x86/urgent] x86, relocs: ignore R_386_NONE in kernel relocation entries |
| |
Commit-ID: 46176b4f6bac19454b7b5c35f68594b85850a600 Gitweb: http://git.kernel.org/tip/46176b4f6bac19454b7b5c35f68594b85850a600 Author: Tejun Heo <tj@kernel.org> AuthorDate: Tue, 26 May 2009 14:42:40 +0900 Committer: H. Peter Anvin <hpa@zytor.com> CommitDate: Mon, 25 May 2009 22:52:49 -0700
x86, relocs: ignore R_386_NONE in kernel relocation entries
For relocatable 32bit kernels, boot/compressed/relocs.c processes relocation entries in the kernel image and appends it to the kernel image such that boot/compressed/head_32.S can relocate the kernel. The kernel image is one statically linked object and only uses two relocation types - R_386_PC32 and R_386_32, of the two only the latter needs massaging during kernel relocation and thus handled by relocs. R_386_PC32 is ignored and all other relocation types are considered error.
When the target of a relocation resides in a discarded section, binutils doesn't throw away the relocation record but nullifies it by changing it to R_386_NONE, which unfortunately makes relocs fail.
The problem was triggered by yet out-of-tree x86 stack unwind patches but given the binutils behavior, ignoring R_386_NONE is the right thing to do.
The problem has been tracked down to binutils behavior by Jan Beulich.
[ Impact: fix build with certain binutils by ignoring R_386_NONE ]
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Beulich <JBeulich@novell.com> Cc: Ingo Molnar <mingo@elte.hu> LKML-Reference: <4A1B8150.40702@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
--- arch/x86/boot/compressed/relocs.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c index 857e492..bbeb0c3 100644 --- a/arch/x86/boot/compressed/relocs.c +++ b/arch/x86/boot/compressed/relocs.c @@ -504,8 +504,11 @@ static void walk_relocs(void (*visit)(Elf32_Rel *rel, Elf32_Sym *sym)) if (sym->st_shndx == SHN_ABS) { continue; } - if (r_type == R_386_PC32) { - /* PC relative relocations don't need to be adjusted */ + if (r_type == R_386_NONE || r_type == R_386_PC32) { + /* + * NONE can be ignored and and PC relative + * relocations don't need to be adjusted. + */ } else if (r_type == R_386_32) { /* Visit relocations that need to be adjusted */
| |