powerpc: modules: change r2 save/restore offset for ELFv2 ABI.

ELFv2 uses a different stack offset (24 vs 40) to save r2.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 05b27a5efc7e47c942d2607a14e58c4ff2145cb8..8bfcf1b8b6d400975a11076b02f793641a4aa623 100644 (file)
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -41,6 +41,12 @@
 #define DEBUGP(fmt , ...)
 #endif
 
+#if defined(_CALL_ELF) && _CALL_ELF == 2
+#define R2_STACK_OFFSET 24
+#else
+#define R2_STACK_OFFSET 40
+#endif
+
 /* Like PPC32, we need little trampolines to do > 24-bit jumps (into
    the kernel itself).  But on PPC64, these need to be used for every
    jump, actually, to reset r2 (TOC+0x8000). */
@@ -61,14 +67,14 @@ struct ppc64_stub_entry
    r2) into the stub. */
 static struct ppc64_stub_entry ppc64_stub =
 { .jump = {
-       0x3d820000, /* addis   r12,r2, <high> */
-       0x398c0000, /* addi    r12,r12, <low> */
+       0x3d820000,                     /* addis   r12,r2, <high> */
+       0x398c0000,                     /* addi    r12,r12, <low> */
        /* Save current r2 value in magic place on the stack. */
-       0xf8410028, /* std     r2,40(r1) */
-       0xe96c0020, /* ld      r11,32(r12) */
-       0xe84c0028, /* ld      r2,40(r12) */
-       0x7d6903a6, /* mtctr   r11 */
-       0x4e800420  /* bctr */
+       0xf8410000|R2_STACK_OFFSET,     /* std     r2,R2_STACK_OFFSET(r1) */
+       0xe96c0020,                     /* ld      r11,32(r12) */
+       0xe84c0028,                     /* ld      r2,40(r12) */
+       0x7d6903a6,                     /* mtctr   r11 */
+       0x4e800420                      /* bctr */
 } };
 
 /* Count how many different 24-bit relocations (different symbol,
@@ -338,7 +344,8 @@ static int restore_r2(u32 *instruction, struct module *me)
                       me->name, *instruction);
                return 0;
        }
-       *instruction = 0xe8410028;      /* ld r2,40(r1) */
+       /* ld r2,R2_STACK_OFFSET(r1) */
+       *instruction = 0xe8410000 | R2_STACK_OFFSET;
        return 1;
 }