MN10300: Add support for new ELF relocs in kernel modules

Add support for new relocs which may show up in MN10300 kernel modules due to
linker relaxation.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 38 insertions, 3 deletions

diff --git a/arch/mn10300/include/asm/elf.h b/arch/mn10300/include/asm/elf.h
index 49105462e6fc..75a70aa9fd6f 100644
--- a/arch/mn10300/include/asm/elf.h
+++ b/arch/mn10300/include/asm/elf.h
@@ -28,6 +28,8 @@
 #define R_MN10300_PCREL8        6       /* PC-relative 8-bit signed.  */
 #define R_MN10300_24            9       /* Direct 24 bit.  */
 #define R_MN10300_RELATIVE      23      /* Adjust by program base.  */
+#define R_MN10300_SYM_DIFF      33      /* Adjustment when relaxing. */
+#define R_MN10300_ALIGN         34      /* Alignment requirement. */
 
 /*
  * ELF register definitions..
diff --git a/arch/mn10300/kernel/module.c b/arch/mn10300/kernel/module.c
index 4fa0e3648d8e..6aea7fd76993 100644
--- a/arch/mn10300/kernel/module.c
+++ b/arch/mn10300/kernel/module.c
@@ -1,6 +1,6 @@
 /* MN10300 Kernel module helper routines
  *
- * Copyright (C) 2007, 2008 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2007, 2008, 2009 Red Hat, Inc. All Rights Reserved.
  * Written by Mark Salter (msalter@redhat.com)
  * - Derived from arch/i386/kernel/module.c
  *
@@ -103,10 +103,10 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
                        unsigned int relsec,
                        struct module *me)
 {
-        unsigned int i;
+        unsigned int i, sym_diff_seen = 0;
         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
         Elf32_Sym *sym;
-        Elf32_Addr relocation;
+        Elf32_Addr relocation, sym_diff_val = 0;
         uint8_t *location;
         uint32_t value;
 
@@ -126,6 +126,22 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
                 /* this is the adjustment to be made */
                 relocation = sym->st_value + rel[i].r_addend;
 
+                if (sym_diff_seen) {
+                        switch (ELF32_R_TYPE(rel[i].r_info)) {
+                        case R_MN10300_32:
+                        case R_MN10300_24:
+                        case R_MN10300_16:
+                        case R_MN10300_8:
+                                relocation -= sym_diff_val;
+                                sym_diff_seen = 0;
+                                break;
+                        default:
+                                printk(KERN_ERR "module %s: Unexpected SYM_DIFF relocation: %u\n",
+                                       me->name, ELF32_R_TYPE(rel[i].r_info));
+                                return -ENOEXEC;
+                        }
+                }
+
                 switch (ELF32_R_TYPE(rel[i].r_info)) {
                         /* for the first four relocation types, we simply
                          * store the adjustment at the location given */
@@ -157,12 +173,29 @@ int apply_relocate_add(Elf32_Shdr *sechdrs,
                         *location = relocation - (uint32_t) location;
                         break;
 
+                case R_MN10300_SYM_DIFF:
+                        /* This is used to adjust the next reloc as required
+                         * by relaxation. */
+                        sym_diff_seen = 1;
+                        sym_diff_val = sym->st_value;
+                        break;
+
+                case R_MN10300_ALIGN:
+                        /* Just ignore the ALIGN relocs.
+                         * Only interesting if kernel performed relaxation. */
+                        continue;
+
                 default:
                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
                                me->name, ELF32_R_TYPE(rel[i].r_info));
                         return -ENOEXEC;
                 }
         }
+        if (sym_diff_seen) {
+                printk(KERN_ERR "module %s: Nothing follows SYM_DIFF relocation: %u\n",
+                                       me->name, ELF32_R_TYPE(rel[i].r_info));
+                return -ENOEXEC;
+        }
         return 0;
 }