1 files changed, 38 insertions, 2 deletions

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 37c59654c133..78054a41d134 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -118,6 +118,34 @@ umalloc(size_t size)
         return addr;
 }
 
+static unsigned char ideal_nop5_x86_64[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
+static unsigned char ideal_nop5_x86_32[5] = { 0x3e, 0x8d, 0x74, 0x26, 0x00 };
+static unsigned char *ideal_nop;
+
+static char rel_type_nop;
+
+static int (*make_nop)(void *map, size_t const offset);
+
+static int make_nop_x86(void *map, size_t const offset)
+{
+        uint32_t *ptr;
+        unsigned char *op;
+
+        /* Confirm we have 0xe8 0x0 0x0 0x0 0x0 */
+        ptr = map + offset;
+        if (*ptr != 0)
+                return -1;
+
+        op = map + offset - 1;
+        if (*op != 0xe8)
+                return -1;
+
+        /* convert to nop */
+        ulseek(fd_map, offset - 1, SEEK_SET);
+        uwrite(fd_map, ideal_nop, 5);
+        return 0;
+}
+
 /*
  * Get the whole file as a programming convenience in order to avoid
  * malloc+lseek+read+free of many pieces.  If successful, then mmap
@@ -301,7 +329,11 @@ do_file(char const *const fname)
                         w2(ehdr->e_machine), fname);
                 fail_file();
                 break;
-        case EM_386:     reltype = R_386_32;                   break;
+        case EM_386:
+                reltype = R_386_32;
+                make_nop = make_nop_x86;
+                ideal_nop = ideal_nop5_x86_32;
+                break;
         case EM_ARM:     reltype = R_ARM_ABS32;
                          altmcount = "__gnu_mcount_nc";
                          break;
@@ -312,7 +344,11 @@ do_file(char const *const fname)
         case EM_S390:    /* reltype: e_class    */ gpfx = '_'; break;
         case EM_SH:      reltype = R_SH_DIR32;                 break;
         case EM_SPARCV9: reltype = R_SPARC_64;     gpfx = '_'; break;
-        case EM_X86_64:  reltype = R_X86_64_64;                break;
+        case EM_X86_64:
+                make_nop = make_nop_x86;
+                ideal_nop = ideal_nop5_x86_64;
+                reltype = R_X86_64_64;
+                break;
         }  /* end switch */
 
         switch (ehdr->e_ident[EI_CLASS]) {