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Commit af64d2aa authored by AKASHI Takahiro's avatar AKASHI Takahiro Committed by Will Deacon
Browse files

ftrace: Add arm64 support to recordmcount 



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.

Acked-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAKASHI Takahiro <takahiro.akashi@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 26e2ae39

arch/arm64/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -30,12 +30,14 @@ config ARM64 
	select HAVE_ARCH_JUMP_LABEL

	select HAVE_ARCH_KGDB

	select HAVE_ARCH_TRACEHOOK

	select HAVE_C_RECORDMCOUNT

	select HAVE_DEBUG_BUGVERBOSE

	select HAVE_DEBUG_KMEMLEAK

	select HAVE_DMA_API_DEBUG

	select HAVE_DMA_ATTRS

	select HAVE_DMA_CONTIGUOUS

	select HAVE_EFFICIENT_UNALIGNED_ACCESS

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_GENERIC_DMA_COHERENT

	select HAVE_HW_BREAKPOINT if PERF_EVENTS

	select HAVE_MEMBLOCK

scripts/recordmcount.c

+7 −0
Original line number Diff line number Diff line
@@ -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 +352,8 @@ 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; gpfx = '_'; break;

	case EM_IA_64:	 reltype = R_IA64_IMM64;   gpfx = '_'; break;

	case EM_METAG:	 reltype = R_METAG_ADDR32;

			 altmcount = "_mcount_wrapper";

scripts/recordmcount.pl

+5 −0
Original line number Diff line number Diff line
@@ -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\$";

    $type = ".quad";

} elsif ($arch eq "ia64") {

    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$";

    $type = "data8";