ARM: improve module relocation fixup diagnostics

Current diagnostics are rather poor when things go wrong:
  ipv6: relocation out of range, section 2 reloc 0 sym 'snmp_mib_free'

Let's include a little more information about the problem:
  ipv6: section 2 reloc 0 sym 'snmp_mib_free': relocation 28 out of range (0xbf0000a4 -> 0xc11b4858)

so that we show exactly what the problem is - not only what type of
relocation but also the offending address range too.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 14 insertions, 13 deletions

diff --git a/arch/arm/kernel/module.c b/arch/arm/kernel/module.c
index 2cfe816..980fe20 100644
--- a/arch/arm/kernel/module.c
+++ b/arch/arm/kernel/module.c
@@ -75,6 +75,7 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 	for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) {
 		unsigned long loc;
 		Elf32_Sym *sym;
+		const char *symname;
 		s32 offset;
 #ifdef CONFIG_THUMB2_KERNEL
 		u32 upper, lower, sign, j1, j2;
@@ -82,18 +83,18 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 
 		offset = ELF32_R_SYM(rel->r_info);
 		if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) {
-			printk(KERN_ERR "%s: bad relocation, section %d reloc %d\n",
+			pr_err("%s: section %u reloc %u: bad relocation sym offset\n",
 				module->name, relindex, i);
 			return -ENOEXEC;
 		}
 
 		sym = ((Elf32_Sym *)symsec->sh_addr) + offset;
+		symname = strtab + sym->st_name;
 
 		if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) {
-			printk(KERN_ERR "%s: out of bounds relocation, "
-				"section %d reloc %d offset %d size %d\n",
-				module->name, relindex, i, rel->r_offset,
-				dstsec->sh_size);
+			pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n",
+			       module->name, relindex, i, symname,
+			       rel->r_offset, dstsec->sh_size);
 			return -ENOEXEC;
 		}
 
@@ -119,10 +120,10 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 			if (offset & 3 ||
 			    offset <= (s32)0xfe000000 ||
 			    offset >= (s32)0x02000000) {
-				printk(KERN_ERR
-				       "%s: relocation out of range, section "
-				       "%d reloc %d sym '%s'\n", module->name,
-				       relindex, i, strtab + sym->st_name);
+				pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
+				       module->name, relindex, i, symname,
+				       ELF32_R_TYPE(rel->r_info), loc,
+				       sym->st_value);
 				return -ENOEXEC;
 			}
 
@@ -195,10 +196,10 @@ apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex,
 			if (!(offset & 1) ||
 			    offset <= (s32)0xff000000 ||
 			    offset >= (s32)0x01000000) {
-				printk(KERN_ERR
-				       "%s: relocation out of range, section "
-				       "%d reloc %d sym '%s'\n", module->name,
-				       relindex, i, strtab + sym->st_name);
+				pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n",
+				       module->name, relindex, i, symname,
+				       ELF32_R_TYPE(rel->r_info), loc,
+				       sym->st_value);
 				return -ENOEXEC;
 			}