On 03/13/2014 09:38 PM, Will Deacon wrote:
On Thu, Mar 13, 2014 at 10:13:46AM +0000, AKASHI Takahiro wrote:
Recordmcount utility under scripts is run, after compiling each object,
to find out all the locations of calling _mcount() and put them into
specific seciton named __mcount_loc.
Then linker collects all such information into a table in the kernel image
(between __start_mcount_loc and __stop_mcount_loc) for later use by ftrace.
This patch adds arm64 specific definitions to identify such locations.
There are two types of implementation, C and Perl. On arm64, only C version
is used to build the kernel now that CONFIG_HAVE_C_RECORDMCOUNT is on.
But Perl version is also maintained.
This patch also contains a workaround just in case where a header file,
elf.h, on host machine doesn't have definitions of EM_AARCH64 nor
R_AARCH64_ABS64. Without them, compiling C version of recordmcount will
fail.
[...]
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 9c22317..047c8cd 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -40,6 +40,11 @@
#define R_METAG_NONE 3
#endif
+#ifndef EM_AARCH64
+#define EM_AARCH64 183
+#define R_AARCH64_ABS64 257
+#endif
+
static int fd_map; /* File descriptor for file being modified. */
static int mmap_failed; /* Boolean flag. */
static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */
@@ -347,6 +352,10 @@ do_file(char const *const fname)
case EM_ARM: reltype = R_ARM_ABS32;
altmcount = "__gnu_mcount_nc";
break;
+ case EM_AARCH64:
+ reltype = R_AARCH64_ABS64;
+ altmcount = "_mcount";
Shouldn't you be setting gpfx = '_' instead of overriding altmcount like
this?
Yep. Fix it.
+ break;
case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
case EM_METAG: reltype = R_METAG_ADDR32;
altmcount = "_mcount_wrapper";
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 91280b8..397b6b8 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -279,6 +279,11 @@ if ($arch eq "x86_64") {
$mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24|THM_CALL)" .
"\\s+(__gnu_mcount_nc|mcount)\$";
+} elsif ($arch eq "arm64") {
+ $alignment = 3;
+ $section_type = '%progbits';
+ $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_AARCH64_CALL26\\s+_mcount\$";
What about "mcount" (i.e. no underscore)?
I don't think it works since such regex doesn't match to "CALL26 _mcount".
Thanks,
-Takahiro AKASHI
Will
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