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From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, "Martin KaFai Lau" <kafai@fb.com>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"John Fastabend" <john.fastabend@gmail.com>,
	"KP Singh" <kpsingh@chromium.org>,
	"Stanislav Fomichev" <sdf@google.com>,
	"Hao Luo" <haoluo@google.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Björn Töpel" <bjorn@kernel.org>,
	"Steven Rostedt" <rostedt@goodmis.org>
Subject: [PATCHv3 bpf-next 1/2] ftrace: Add HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
Date: Sat,  3 Sep 2022 15:11:53 +0200	[thread overview]
Message-ID: <20220903131154.420467-2-jolsa@kernel.org> (raw)
In-Reply-To: <20220903131154.420467-1-jolsa@kernel.org>

From: "Peter Zijlstra (Intel)" <peterz@infradead.org>

x86 will shortly start using -fpatchable-function-entry for purposes
other than ftrace, make sure the __patchable_function_entry section
isn't merged in the mcount_loc section.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 include/asm-generic/vmlinux.lds.h | 11 ++++++++++-
 kernel/trace/Kconfig              |  6 ++++++
 tools/objtool/check.c             |  3 ++-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 7515a465ec03..13b197ef0d63 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -154,6 +154,14 @@
 #define MEM_DISCARD(sec) *(.mem##sec)
 #endif
 
+#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
+#define KEEP_PATCHABLE		KEEP(*(__patchable_function_entries))
+#define PATCHABLE_DISCARDS
+#else
+#define KEEP_PATCHABLE
+#define PATCHABLE_DISCARDS	*(__patchable_function_entries)
+#endif
+
 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
 /*
  * The ftrace call sites are logged to a section whose name depends on the
@@ -172,7 +180,7 @@
 #define MCOUNT_REC()	. = ALIGN(8);				\
 			__start_mcount_loc = .;			\
 			KEEP(*(__mcount_loc))			\
-			KEEP(*(__patchable_function_entries))	\
+			KEEP_PATCHABLE				\
 			__stop_mcount_loc = .;			\
 			ftrace_stub_graph = ftrace_stub;	\
 			ftrace_ops_list_func = arch_ftrace_ops_list_func;
@@ -1024,6 +1032,7 @@
 
 #define COMMON_DISCARDS							\
 	SANITIZER_DISCARDS						\
+	PATCHABLE_DISCARDS						\
 	*(.discard)							\
 	*(.discard.*)							\
 	*(.modinfo)							\
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 1052126bdca2..e9e95c790b8e 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -51,6 +51,12 @@ config HAVE_DYNAMIC_FTRACE_WITH_ARGS
 	 This allows for use of regs_get_kernel_argument() and
 	 kernel_stack_pointer().
 
+config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
+	bool
+	help
+	  If the architecture generates __patchable_function_entries sections
+	  but does not want them included in the ftrace locations.
+
 config HAVE_FTRACE_MCOUNT_RECORD
 	bool
 	help
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 0cec74da7ffe..f23e8d11f6d4 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4110,7 +4110,8 @@ static int validate_ibt(struct objtool_file *file)
 		    !strcmp(sec->name, "__bug_table")			||
 		    !strcmp(sec->name, "__ex_table")			||
 		    !strcmp(sec->name, "__jump_table")			||
-		    !strcmp(sec->name, "__mcount_loc"))
+		    !strcmp(sec->name, "__mcount_loc")			||
+		    strstr(sec->name, "__patchable_function_entries"))
 			continue;
 
 		list_for_each_entry(reloc, &sec->reloc->reloc_list, list)
-- 
2.37.2


  reply	other threads:[~2022-09-03 13:12 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-03 13:11 [PATCHv3 bpf-next 0/2] bpf,ftrace: bpf dispatcher function fix Jiri Olsa
2022-09-03 13:11 ` Jiri Olsa [this message]
2022-09-03 13:11 ` [PATCHv3 bpf-next 2/2] bpf: Move bpf_dispatcher function out of ftrace locations Jiri Olsa
2022-09-05 15:23   ` Steven Rostedt
2022-09-06 10:07     ` Jiri Olsa
2022-09-06 11:32   ` Peter Zijlstra
2022-09-16 20:30 ` [PATCHv3 bpf-next 0/2] bpf,ftrace: bpf dispatcher function fix patchwork-bot+netdevbpf

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