[PATCH resend 1/4] ARM: handle interworking and out-of-range relocations separately
From: Ard Biesheuvel <hidden>
Date: 2015-01-31 19:49:16
Subsystem:
arm port, the rest · Maintainers:
Russell King, Linus Torvalds
Currently, interworking calls on module boundaries are not supported, and are handled by the same error handling code path as non-interworking calls whose targets are simply out of range. Before modifying the handling of those out-of-range jump and call relocations in a subsequent patch, move the handling of interworking restrictions out of it. Acked-by: Nicolas Pitre <redacted> Signed-off-by: Ard Biesheuvel <redacted> --- arch/arm/kernel/module.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 6a4dffefd357..16804df4857c 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c@@ -98,14 +98,19 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, case R_ARM_PC24: case R_ARM_CALL: case R_ARM_JUMP24: + if (sym->st_value & 3) { + pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (ARM -> Thumb)\n", + module->name, relindex, i, symname); + return -ENOEXEC; + } + offset = __mem_to_opcode_arm(*(u32 *)loc); offset = (offset & 0x00ffffff) << 2; if (offset & 0x02000000) offset -= 0x04000000; offset += sym->st_value - loc; - if (offset & 3 || - offset <= (s32)0xfe000000 || + if (offset <= (s32)0xfe000000 || offset >= (s32)0x02000000) { pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", module->name, relindex, i, symname,
@@ -155,6 +160,22 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, #ifdef CONFIG_THUMB2_KERNEL case R_ARM_THM_CALL: case R_ARM_THM_JUMP24: + /* + * For function symbols, only Thumb addresses are + * allowed (no interworking). + * + * For non-function symbols, the destination + * has no specific ARM/Thumb disposition, so + * the branch is resolved under the assumption + * that interworking is not required. + */ + if (ELF32_ST_TYPE(sym->st_info) == STT_FUNC && + !(sym->st_value & 1)) { + pr_err("%s: section %u reloc %u sym '%s': unsupported interworking call (Thumb -> ARM)\n", + module->name, relindex, i, symname); + return -ENOEXEC; + } + upper = __mem_to_opcode_thumb16(*(u16 *)loc); lower = __mem_to_opcode_thumb16(*(u16 *)(loc + 2));
@@ -182,18 +203,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, offset -= 0x02000000; offset += sym->st_value - loc; - /* - * For function symbols, only Thumb addresses are - * allowed (no interworking). - * - * For non-function symbols, the destination - * has no specific ARM/Thumb disposition, so - * the branch is resolved under the assumption - * that interworking is not required. - */ - if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC && - !(offset & 1)) || - offset <= (s32)0xff000000 || + if (offset <= (s32)0xff000000 || offset >= (s32)0x01000000) { pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", module->name, relindex, i, symname,
--
1.8.3.2