ftrace/x86: mcount offset calculation

Do the mcount offset adjustment in the recordmcount.pl/recordmcount.[ch] at compile time and not in ftrace_call_adjust at run time. Signed-off-by: Martin Schwidefsky <[email protected]> Signed-off-by: Steven Rostedt <[email protected]>
diverger · May 16, 2011 · 521ccb5 · 521ccb5
1 parent 07d8b59
commit 521ccb5
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Showing 3 changed files with 7 additions and 4 deletions.
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
@@ -38,11 +38,10 @@ extern void mcount(void);
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
 	/*
-	 * call mcount is "e8 <4 byte offset>"
-	 * The addr points to the 4 byte offset and the caller of this
-	 * function wants the pointer to e8. Simply subtract one.
+	 * addr is the address of the mcount call instruction.
+	 * recordmcount does the necessary offset calculation.
 	 */
-	return addr - 1;
+	return addr;
 }
 
 #ifdef CONFIG_DYNAMIC_FTRACE

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
@@ -335,6 +335,7 @@ do_file(char const *const fname)
 		reltype = R_386_32;
 		make_nop = make_nop_x86;
 		ideal_nop = ideal_nop5_x86_32;
+		mcount_adjust_32 = -1;
 		break;
 	case EM_ARM:	 reltype = R_ARM_ABS32;
 			 altmcount = "__gnu_mcount_nc";
@@ -350,6 +351,7 @@ do_file(char const *const fname)
 		make_nop = make_nop_x86;
 		ideal_nop = ideal_nop5_x86_64;
 		reltype = R_X86_64_64;
+		mcount_adjust_64 = -1;
 		break;
 	}  /* end switch */
 

diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
@@ -223,6 +223,7 @@ sub check_objcopy
     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
     $type = ".quad";
     $alignment = 8;
+    $mcount_adjust = -1;
 
     # force flags for this arch
     $ld .= " -m elf_x86_64";
@@ -232,6 +233,7 @@ sub check_objcopy
 
 } elsif ($arch eq "i386") {
     $alignment = 4;
+    $mcount_adjust = -1;
 
     # force flags for this arch
     $ld .= " -m elf_i386";