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authorTejun Heo <tj@kernel.org>2009-05-26 01:42:40 -0400
committerH. Peter Anvin <hpa@zytor.com>2009-05-26 01:52:49 -0400
commit46176b4f6bac19454b7b5c35f68594b85850a600 (patch)
treec67571802f614aa361726d513e9a8fcaee603fb1 /arch/x86/boot/compressed/relocs.c
parent71c9d8b68b299bef614afc7907393564a9f1476f (diff)
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>
Diffstat (limited to 'arch/x86/boot/compressed/relocs.c')
-rw-r--r--arch/x86/boot/compressed/relocs.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/boot/compressed/relocs.c b/arch/x86/boot/compressed/relocs.c
index 857e492c571e..bbeb0c3fbd90 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))
504 if (sym->st_shndx == SHN_ABS) { 504 if (sym->st_shndx == SHN_ABS) {
505 continue; 505 continue;
506 } 506 }
507 if (r_type == R_386_PC32) { 507 if (r_type == R_386_NONE || r_type == R_386_PC32) {
508 /* PC relative relocations don't need to be adjusted */ 508 /*
509 * NONE can be ignored and and PC relative
510 * relocations don't need to be adjusted.
511 */
509 } 512 }
510 else if (r_type == R_386_32) { 513 else if (r_type == R_386_32) {
511 /* Visit relocations that need to be adjusted */ 514 /* Visit relocations that need to be adjusted */