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From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	 Steven Rostedt <rostedt@goodmis.org>,
	Mark Rutland <mark.rutland@arm.com>
Cc: Torsten Duwe <duwe@suse.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: [PATCH 3/3] arm64: use -fpatchable-function-entry if available
Date: Mon, 19 Aug 2019 11:29:02 +0000	[thread overview]
Message-ID: <20190819191759.04bf63d7@xhacker.debian> (raw)
In-Reply-To: <20190819191530.0f47b9b1@xhacker.debian>

From: Torsten Duwe <duwe@suse.de>

Test whether gcc supports -fpatchable-function-entry and use it to promote
DYNAMIC_FTRACE to DYNAMIC_FTRACE_WITH_REGS. Amend support for the new
object section that holds the locations (__patchable_function_entries) and
define a proper "notrace" attribute to switch it off.

Signed-off-by: Torsten Duwe <duwe@suse.de>
---
 arch/arm64/Kconfig  | 2 ++
 arch/arm64/Makefile | 5 +++++
 kernel/module.c     | 7 ++++++-
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3adcec05b1f6..663392d1eae2 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -144,6 +144,8 @@ config ARM64
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DMA_CONTIGUOUS
 	select HAVE_DYNAMIC_FTRACE
+	select HAVE_DYNAMIC_FTRACE_WITH_REGS \
+		if $(cc-option,-fpatchable-function-entry=2)
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	select HAVE_FAST_GUP
 	select HAVE_FTRACE_MCOUNT_RECORD
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 61de992bbea3..e827ad0298ab 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -104,6 +104,11 @@ ifeq ($(CONFIG_ARM64_MODULE_PLTS),y)
 KBUILD_LDFLAGS_MODULE	+= -T $(srctree)/arch/arm64/kernel/module.lds
 endif
 
+ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)
+  KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
+  CC_FLAGS_FTRACE := -fpatchable-function-entry=2
+endif
+
 # Default value
 head-y		:= arch/arm64/kernel/head.o
 
diff --git a/kernel/module.c b/kernel/module.c
index 5933395af9a0..0759f89adbd3 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3136,7 +3136,12 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 #endif
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 	/* sechdrs[0].sh_size is always zero */
-	mod->ftrace_callsites = section_objs(info, "__mcount_loc",
+	mod->ftrace_callsites = section_objs(info,
+#ifdef CC_USING_PATCHABLE_FUNCTION_ENTRY
+					     "__patchable_function_entries",
+#else
+					     "__mcount_loc",
+#endif
 					     sizeof(*mod->ftrace_callsites),
 					     &mod->num_ftrace_callsites);
 #endif
-- 
2.23.0.rc1


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      parent reply	other threads:[~2019-08-19 11:29 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-19 11:26 [PATCH 0/3] arm64: ftrace with regs Jisheng Zhang
2019-08-19 11:27 ` [PATCH 1/3] ftrace: introdue ftrace_call_init Jisheng Zhang
2019-08-19 11:30   ` Jisheng Zhang
2019-08-20  9:27   ` Miroslav Benes
2019-08-21  2:12     ` Jisheng Zhang
2019-08-26 10:14     ` Jisheng Zhang
2019-08-19 11:28 ` [PATCH 2/3] arm64: implement ftrace with regs Jisheng Zhang
2019-08-19 11:29 ` Jisheng Zhang [this message]

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