3 files changed, 29 insertions, 7 deletions

diff --git a/arch/powerpc/include/asm/module.h b/arch/powerpc/include/asm/module.h
index 08454880a2c0..0192a4ee2bc2 100644
--- a/arch/powerpc/include/asm/module.h
+++ b/arch/powerpc/include/asm/module.h
@@ -87,5 +87,10 @@ struct exception_table_entry;
 void sort_ex_table(struct exception_table_entry *start,
                    struct exception_table_entry *finish);
 
+#ifdef CONFIG_MODVERSIONS
+#define ARCH_RELOCATES_KCRCTAB
+
+extern const unsigned long reloc_start[];
+#endif
 #endif /* __KERNEL__ */
 #endif  /* _ASM_POWERPC_MODULE_H */
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 27735a7ac12b..dcd01c82e701 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -38,6 +38,9 @@ jiffies = jiffies_64 + 4;
 #endif
 SECTIONS
 {
+        . = 0;
+        reloc_start = .;
+
         . = KERNELBASE;
 
 /*
diff --git a/kernel/module.c b/kernel/module.c
index 12afc5a3ddd3..a65dc787a27b 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -880,11 +880,23 @@ static int try_to_force_load(struct module *mod, const char *reason)
 }
 
 #ifdef CONFIG_MODVERSIONS
+/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
+static unsigned long maybe_relocated(unsigned long crc,
+                                     const struct module *crc_owner)
+{
+#ifdef ARCH_RELOCATES_KCRCTAB
+        if (crc_owner == NULL)
+                return crc - (unsigned long)reloc_start;
+#endif
+        return crc;
+}
+
 static int check_version(Elf_Shdr *sechdrs,
                          unsigned int versindex,
                          const char *symname,
                          struct module *mod, 
-                         const unsigned long *crc)
+                         const unsigned long *crc,
+                         const struct module *crc_owner)
 {
         unsigned int i, num_versions;
         struct modversion_info *versions;
@@ -905,10 +917,10 @@ static int check_version(Elf_Shdr *sechdrs,
                 if (strcmp(versions[i].name, symname) != 0)
                         continue;
 
-                if (versions[i].crc == *crc)
+                if (versions[i].crc == maybe_relocated(*crc, crc_owner))
                         return 1;
                 DEBUGP("Found checksum %lX vs module %lX\n",
-                       *crc, versions[i].crc);
+                       maybe_relocated(*crc, crc_owner), versions[i].crc);
                 goto bad_version;
         }
 
@@ -931,7 +943,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
         if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL,
                          &crc, true, false))
                 BUG();
-        return check_version(sechdrs, versindex, "module_layout", mod, crc);
+        return check_version(sechdrs, versindex, "module_layout", mod, crc,
+                             NULL);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -949,7 +962,8 @@ static inline int check_version(Elf_Shdr *sechdrs,
                                 unsigned int versindex,
                                 const char *symname,
                                 struct module *mod, 
-                                const unsigned long *crc)
+                                const unsigned long *crc,
+                                const struct module *crc_owner)
 {
         return 1;
 }
@@ -984,8 +998,8 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
         /* use_module can fail due to OOM,
            or module initialization or unloading */
         if (sym) {
-                if (!check_version(sechdrs, versindex, name, mod, crc) ||
-                    !use_module(mod, owner))
+                if (!check_version(sechdrs, versindex, name, mod, crc, owner)
+                    || !use_module(mod, owner))
                         sym = NULL;
         }
         return sym;