MN10300: Add support for new ELF relocs in kernel modules
Mark Salter [Wed, 17 Jun 2009 21:51:11 +0000 (22:51 +0100)]
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>

arch/mn10300/include/asm/elf.h
arch/mn10300/kernel/module.c

index 4910546..75a70aa 100644 (file)
@@ -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..
index 4fa0e36..6aea7fd 100644 (file)
@@ -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;
 }