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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 <schwidefsky@de.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Martin Schwidefsky 2011-05-10 10:10:41 +02:00 committed by Steven Rostedt
parent 07d8b595f3
commit 521ccb5c4a
3 changed files with 7 additions and 4 deletions
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7
arch/x86/include/asm/ftrace.h
View File

@ -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

2
scripts/recordmcount.c
View File

@ -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 */

2
scripts/recordmcount.pl
View File

@ -223,6 +223,7 @@ if ($arch eq "x86_64") {
$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
$ld .= " -m elf_x86_64";
@ -232,6 +233,7 @@ if ($arch eq "x86_64") {
} elsif ($arch eq "i386") {
$alignment = 4;
$mcount_adjust = -1;
# force flags for this arch
$ld .= " -m elf_i386";