1 files changed, 19 insertions, 21 deletions

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 78cdd7fbecd0..f202d0731b06 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -292,19 +292,24 @@ static int
 __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
         unsigned int op[2];
-        unsigned long ip = rec->ip;
+        void *ip = (void *)rec->ip;
 
         /* read where this goes */
-        if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2))
+        if (probe_kernel_read(op, ip, sizeof(op)))
                 return -EFAULT;
 
         /*
-         * It should be pointing to two nops or
-         *  b +8; ld r2,40(r1)
+         * We expect to see:
+         *
+         * b +8
+         * ld r2,XX(r1)
+         *
+         * The load offset is different depending on the ABI. For simplicity
+         * just mask it out when doing the compare.
          */
-        if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) &&
-            ((op[0] != PPC_INST_NOP) || (op[1] != PPC_INST_NOP))) {
-                printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]);
+        if ((op[0] != 0x48000008) || ((op[1] & 0xffff00000) != 0xe8410000)) {
+                printk(KERN_ERR "Unexpected call sequence: %x %x\n",
+                        op[0], op[1]);
                 return -EINVAL;
         }
 
@@ -314,23 +319,16 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
                 return -EINVAL;
         }
 
-        /* create the branch to the trampoline */
-        op[0] = create_branch((unsigned int *)ip,
-                              rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
-        if (!op[0]) {
-                printk(KERN_ERR "REL24 out of range!\n");
+        /* Ensure branch is within 24 bits */
+        if (create_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) {
+                printk(KERN_ERR "Branch out of range");
                 return -EINVAL;
         }
 
-        /* ld r2,40(r1) */
-        op[1] = 0xe8410028;
-
-        pr_devel("write to %lx\n", rec->ip);
-
-        if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
-                return -EPERM;
-
-        flush_icache_range(ip, ip + 8);
+        if (patch_branch(ip, rec->arch.mod->arch.tramp, BRANCH_SET_LINK)) {
+                printk(KERN_ERR "REL24 out of range!\n");
+                return -EINVAL;
+        }
 
         return 0;
 }