ARM: 8219/1: handle interworking and out-of-range relocations separately

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 <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 2e11961..af791f4 100644 (file)
--- 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,