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Subject[PATCH 1/6] riscv/ftrace: Add RECORD_MCOUNT support
Date
Now recordmcount.pl recognizes RISC-V object files. For the mechanism to
work, we have to disable the linker relaxation. This is because
relaxation happens after the script records offsets of _mcount call
sites, resulting in a unreliable record.

Cc: Greentime Hu <greentime@andestech.com>
Signed-off-by: Alan Kao <alankao@andestech.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/Makefile | 6 +++++-
scripts/recordmcount.pl | 5 +++++
3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 504ba386b22e..346dd1b0fb05 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -112,6 +112,7 @@ config ARCH_RV64I
select 64BIT
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_FTRACE_MCOUNT_RECORD

endchoice

diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 6719dd30ec5b..2bc39c6d9662 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -10,7 +10,11 @@

LDFLAGS :=
OBJCOPYFLAGS := -O binary
-LDFLAGS_vmlinux :=
+ifeq ($(CONFIG_DYNAMIC_FTRACE),y)
+ LDFLAGS_vmlinux := --no-relax
+else
+ LDFLAGS_vmlinux :=
+endif
KBUILD_AFLAGS_MODULE += -fPIC
KBUILD_CFLAGS_MODULE += -fPIC

diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 2033af758173..d44d55db7c06 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -376,6 +376,11 @@ if ($arch eq "x86_64") {
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s__mcount\$";
$type = ".quad";
$alignment = 8;
+} elsif ($arch eq "riscv") {
+ $function_regex = "^([0-9a-fA-F]+)\\s+<([^.0-9][0-9a-zA-Z_\\.]+)>:";
+ $mcount_regex = "^\\s*([0-9a-fA-F]+):\\sR_RISCV_CALL\\s_mcount\$";
+ $type = ".quad";
+ $alignment = 2;
} else {
die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
}
--
2.15.1
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