I have not done extensive tests yet, but this patch appears to
be working. I'd appreciate people giving it a try and let me
know how it goes.
There is one worrisome "FIXME" in that file, which is not clear
to me. Ralf?
Jun
diff -Nru linux/arch/mips/kernel/module-elf32.c.orig linux/arch/mips/kernel/module-elf32.c
--- linux/arch/mips/kernel/module-elf32.c.orig Fri Jul 25 15:49:23 2003
+++ linux/arch/mips/kernel/module-elf32.c Fri Jan 23 17:58:42 2004
@@ -23,14 +23,11 @@
#include <linux/string.h>
#include <linux/kernel.h>
-struct mips_hi16 {
- struct mips_hi16 *next;
+struct mips_hilo16 {
Elf32_Addr *addr;
Elf32_Addr value;
};
-static struct mips_hi16 *mips_hi16_list;
-
#if 0
#define DEBUGP printk
#else
@@ -78,6 +75,35 @@
return 0;
}
+/*
+ * For the hi16, we should set ((AHL+S) - (short)(AHL+S)) >> 16
+ * For the lo16, we should set (AHL+S) & 0xffff
+ * where
+ * AHL = (AHI << 16 ) + (short)ALO
+ * whereis
+ * AHI = *(hi16 instr loc) & 0xffff // before reloc
+ * ALO = *(lo16 instr loc) & 0xffff // before reloc
+ */
+#define U32_TO_SHORT(x) (((x & 0xffff) ^ 0x8000) - 0x8000)
+static void relocate_hilo16(struct mips_hilo16 *hi, struct mips_hilo16 *lo)
+{
+ u32 AHI, ALO, AHL_S, res_hi, res_lo;
+
+ AHI = *(hi->addr) & 0xffff;
+ ALO = *(lo->addr) & 0xffff;
+ AHL_S = (AHI << 16) + U32_TO_SHORT(ALO) + hi->value;
+
+ res_lo = AHL_S & 0xffff;
+ res_hi = (AHL_S >> 16) + ((res_lo & 0x8000)==0 ? 0 : 1);
+ res_hi &= 0xffff;
+
+ *hi->addr = (*hi->addr & ~0xffff) | res_hi;
+ *lo->addr = (*lo->addr & ~0xffff) | res_lo;
+}
+
+#undef KERN_ERR
+#define KERN_ERR
+
int apply_relocate(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
@@ -85,19 +111,20 @@
struct module *me)
{
unsigned int i;
- Elf32_Rel *rel = (void *)sechdrs[relsec].sh_offset;
+ Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym;
uint32_t *location;
Elf32_Addr v;
+ struct mips_hilo16 hi16, lo16;
DEBUGP("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* This is where to make the change */
- location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_offset
+ location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
/* This is the symbol it is referring to */
- sym = (Elf32_Sym *)sechdrs[symindex].sh_offset
+ sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rel[i].r_info);
if (!sym->st_value) {
printk(KERN_WARNING "%s: Unknown symbol %s\n",
@@ -116,99 +143,52 @@
break;
case R_MIPS_26:
- if (v % 4)
+ if (v % 4) {
printk(KERN_ERR
"module %s: dangerous relocation\n",
me->name);
return -ENOEXEC;
+ }
if ((v & 0xf0000000) !=
- (((unsigned long)location + 4) & 0xf0000000))
+ (((unsigned long)location + 4) & 0xf0000000)) {
printk(KERN_ERR
"module %s: relocation overflow\n",
me->name);
return -ENOEXEC;
+ }
*location = (*location & ~0x03ffffff) |
((*location + (v >> 2)) & 0x03ffffff);
break;
- case R_MIPS_HI16: {
- struct mips_hi16 *n;
-
+ case R_MIPS_HI16:
/*
* We cannot relocate this one now because we don't
* know the value of the carry we need to add. Save
* the information, and let LO16 do the actual
* relocation.
*/
- n = (struct mips_hi16 *) kmalloc(sizeof *n, GFP_KERNEL);
- n->addr = location;
- n->value = v;
- n->next = mips_hi16_list;
- mips_hi16_list = n;
+ hi16.addr = location;
+ hi16.value = v;
break;
- }
-
- case R_MIPS_LO16: {
- unsigned long insnlo = *location;
- Elf32_Addr val, vallo;
-
- /* Sign extend the addend we extract from the lo insn. */
- vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
-
- if (mips_hi16_list != NULL) {
- struct mips_hi16 *l;
-
- l = mips_hi16_list;
- while (l != NULL) {
- struct mips_hi16 *next;
- unsigned long insn;
-
- /*
- * The value for the HI16 had best be
- * the same.
- */
- printk(KERN_ERR "module %s: dangerous "
- "relocation\n", me->name);
- return -ENOEXEC;
-
- /*
- * Do the HI16 relocation. Note that
- * we actually don't need to know
- * anything about the LO16 itself,
- * except where to find the low 16 bits
- * of the addend needed by the LO16.
- */
- insn = *l->addr;
- val = ((insn & 0xffff) << 16) + vallo;
- val += v;
-
- /*
- * Account for the sign extension that
- * will happen in the low bits.
- */
- val = ((val >> 16) + ((val & 0x8000) !=
- 0)) & 0xffff;
-
- insn = (insn & ~0xffff) | val;
- *l->addr = insn;
-
- next = l->next;
- kfree(l);
- l = next;
- }
-
- mips_hi16_list = NULL;
- }
+ case R_MIPS_LO16:
/*
- * Ok, we're done with the HI16 relocs. Now deal with
- * the LO16.
+ * This lo16 entry must have the same value as
+ * the preceeding or last hi16 entry.
*/
- val = v + vallo;
- insnlo = (insnlo & ~0xffff) | (val & 0xffff);
- *location = insnlo;
+ if (v != hi16.value) {
+ printk(KERN_ERR "module %s: HI16/LO16 value mistmatch : %08x vs %08x\n",
+ me->name,
+ hi16.value,
+ v);
+ return -ENOEXEC;
+ }
+
+ lo16.addr = location;
+ lo16.value = v;
+
+ relocate_hilo16(&hi16, &lo16);
break;
- }
default:
printk(KERN_ERR "module %s: Unknown relocation: %u\n",
@@ -225,6 +205,9 @@
unsigned int relsec,
struct module *me)
{
+ if (sechdrs[relsec].sh_size == 0)
+ return 0;
+
printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
me->name);
return -ENOEXEC;
