All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: linux-kernel@vger.kernel.org
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>, Kees Cook <keescook@chromium.org>,
	Will Deacon <will.deacon@arm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Thomas Garnier <thgarnie@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Russell King <linux@armlinux.org.uk>,
	Paul Mackerras <paulus@samba.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Petr Mladek <pmladek@suse.com>, Ingo Molnar <mingo@redhat.com>,
	James Morris <jmorris@namei.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nicolas Pitre <nico@linaro.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jessica Yu <jeyu@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: [PATCH v10 6/6] kernel: tracepoints: add support for relative references
Date: Wed,  4 Jul 2018 10:36:51 +0200	[thread overview]
Message-ID: <20180704083651.24360-7-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20180704083651.24360-1-ard.biesheuvel@linaro.org>

To avoid the need for relocating absolute references to tracepoint
structures at boot time when running relocatable kernels (which may
take a disproportionate amount of space), add the option to emit
these tables as relative references instead.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/tracepoint.h | 19 ++++++--
 kernel/tracepoint.c        | 49 +++++++++++---------
 2 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 19a690b559ca..b130e40d82cb 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -225,6 +225,19 @@ extern void syscall_unregfunc(void);
 		return static_key_false(&__tracepoint_##name.key);	\
 	}
 
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define __TRACEPOINT_ENTRY(name)					\
+	asm("	.section \"__tracepoints_ptrs\", \"a\"		\n"	\
+	    "	.balign 4					\n"	\
+	    "	.long 	__tracepoint_" #name " - .		\n"	\
+	    "	.previous					\n")
+#else
+#define __TRACEPOINT_ENTRY(name)					 \
+	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
+	__attribute__((section("__tracepoints_ptrs"))) =		 \
+		&__tracepoint_##name
+#endif
+
 /*
  * We have no guarantee that gcc and the linker won't up-align the tracepoint
  * structures, so we create an array of pointers that will be used for iteration
@@ -234,11 +247,9 @@ extern void syscall_unregfunc(void);
 	static const char __tpstrtab_##name[]				 \
 	__attribute__((section("__tracepoints_strings"))) = #name;	 \
 	struct tracepoint __tracepoint_##name				 \
-	__attribute__((section("__tracepoints"))) =			 \
+	__attribute__((section("__tracepoints"), used)) =		 \
 		{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
-	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
-	__attribute__((section("__tracepoints_ptrs"))) =		 \
-		&__tracepoint_##name;
+	__TRACEPOINT_ENTRY(name);
 
 #define DEFINE_TRACE(name)						\
 	DEFINE_TRACE_FN(name, NULL, NULL);
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 6dc6356c3327..451c8f5e8345 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -325,6 +325,27 @@ int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
 }
 EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 
+static void for_each_tracepoint_range(struct tracepoint * const *begin,
+		struct tracepoint * const *end,
+		void (*fct)(struct tracepoint *tp, void *priv),
+		void *priv)
+{
+	if (!begin)
+		return;
+
+	if (IS_ENABLED(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)) {
+		const int *iter;
+
+		for (iter = (const int *)begin; iter < (const int *)end; iter++)
+			fct(offset_to_ptr(iter), priv);
+	} else {
+		struct tracepoint * const *iter;
+
+		for (iter = begin; iter < end; iter++)
+			fct(*iter, priv);
+	}
+}
+
 #ifdef CONFIG_MODULES
 bool trace_module_has_bad_taint(struct module *mod)
 {
@@ -389,15 +410,9 @@ EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
  * Ensure the tracer unregistered the module's probes before the module
  * teardown is performed. Prevents leaks of probe and data pointers.
  */
-static void tp_module_going_check_quiescent(struct tracepoint * const *begin,
-		struct tracepoint * const *end)
+static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
 {
-	struct tracepoint * const *iter;
-
-	if (!begin)
-		return;
-	for (iter = begin; iter < end; iter++)
-		WARN_ON_ONCE((*iter)->funcs);
+	WARN_ON_ONCE(tp->funcs);
 }
 
 static int tracepoint_module_coming(struct module *mod)
@@ -448,8 +463,9 @@ static void tracepoint_module_going(struct module *mod)
 			 * Called the going notifier before checking for
 			 * quiescence.
 			 */
-			tp_module_going_check_quiescent(mod->tracepoints_ptrs,
-				mod->tracepoints_ptrs + mod->num_tracepoints);
+			for_each_tracepoint_range(mod->tracepoints_ptrs,
+				mod->tracepoints_ptrs + mod->num_tracepoints,
+				tp_module_going_check_quiescent, NULL);
 			break;
 		}
 	}
@@ -501,19 +517,6 @@ static __init int init_tracepoints(void)
 __initcall(init_tracepoints);
 #endif /* CONFIG_MODULES */
 
-static void for_each_tracepoint_range(struct tracepoint * const *begin,
-		struct tracepoint * const *end,
-		void (*fct)(struct tracepoint *tp, void *priv),
-		void *priv)
-{
-	struct tracepoint * const *iter;
-
-	if (!begin)
-		return;
-	for (iter = begin; iter < end; iter++)
-		fct(*iter, priv);
-}
-
 /**
  * for_each_kernel_tracepoint - iteration on all kernel tracepoints
  * @fct: callback
-- 
2.17.1


WARNING: multiple messages have this Message-ID
From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v10 6/6] kernel: tracepoints: add support for relative references
Date: Wed,  4 Jul 2018 10:36:51 +0200	[thread overview]
Message-ID: <20180704083651.24360-7-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <20180704083651.24360-1-ard.biesheuvel@linaro.org>

To avoid the need for relocating absolute references to tracepoint
structures at boot time when running relocatable kernels (which may
take a disproportionate amount of space), add the option to emit
these tables as relative references instead.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/tracepoint.h | 19 ++++++--
 kernel/tracepoint.c        | 49 +++++++++++---------
 2 files changed, 41 insertions(+), 27 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 19a690b559ca..b130e40d82cb 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -225,6 +225,19 @@ extern void syscall_unregfunc(void);
 		return static_key_false(&__tracepoint_##name.key);	\
 	}
 
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define __TRACEPOINT_ENTRY(name)					\
+	asm("	.section \"__tracepoints_ptrs\", \"a\"		\n"	\
+	    "	.balign 4					\n"	\
+	    "	.long 	__tracepoint_" #name " - .		\n"	\
+	    "	.previous					\n")
+#else
+#define __TRACEPOINT_ENTRY(name)					 \
+	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
+	__attribute__((section("__tracepoints_ptrs"))) =		 \
+		&__tracepoint_##name
+#endif
+
 /*
  * We have no guarantee that gcc and the linker won't up-align the tracepoint
  * structures, so we create an array of pointers that will be used for iteration
@@ -234,11 +247,9 @@ extern void syscall_unregfunc(void);
 	static const char __tpstrtab_##name[]				 \
 	__attribute__((section("__tracepoints_strings"))) = #name;	 \
 	struct tracepoint __tracepoint_##name				 \
-	__attribute__((section("__tracepoints"))) =			 \
+	__attribute__((section("__tracepoints"), used)) =		 \
 		{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
-	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
-	__attribute__((section("__tracepoints_ptrs"))) =		 \
-		&__tracepoint_##name;
+	__TRACEPOINT_ENTRY(name);
 
 #define DEFINE_TRACE(name)						\
 	DEFINE_TRACE_FN(name, NULL, NULL);
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 6dc6356c3327..451c8f5e8345 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -325,6 +325,27 @@ int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
 }
 EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 
+static void for_each_tracepoint_range(struct tracepoint * const *begin,
+		struct tracepoint * const *end,
+		void (*fct)(struct tracepoint *tp, void *priv),
+		void *priv)
+{
+	if (!begin)
+		return;
+
+	if (IS_ENABLED(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)) {
+		const int *iter;
+
+		for (iter = (const int *)begin; iter < (const int *)end; iter++)
+			fct(offset_to_ptr(iter), priv);
+	} else {
+		struct tracepoint * const *iter;
+
+		for (iter = begin; iter < end; iter++)
+			fct(*iter, priv);
+	}
+}
+
 #ifdef CONFIG_MODULES
 bool trace_module_has_bad_taint(struct module *mod)
 {
@@ -389,15 +410,9 @@ EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
  * Ensure the tracer unregistered the module's probes before the module
  * teardown is performed. Prevents leaks of probe and data pointers.
  */
-static void tp_module_going_check_quiescent(struct tracepoint * const *begin,
-		struct tracepoint * const *end)
+static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
 {
-	struct tracepoint * const *iter;
-
-	if (!begin)
-		return;
-	for (iter = begin; iter < end; iter++)
-		WARN_ON_ONCE((*iter)->funcs);
+	WARN_ON_ONCE(tp->funcs);
 }
 
 static int tracepoint_module_coming(struct module *mod)
@@ -448,8 +463,9 @@ static void tracepoint_module_going(struct module *mod)
 			 * Called the going notifier before checking for
 			 * quiescence.
 			 */
-			tp_module_going_check_quiescent(mod->tracepoints_ptrs,
-				mod->tracepoints_ptrs + mod->num_tracepoints);
+			for_each_tracepoint_range(mod->tracepoints_ptrs,
+				mod->tracepoints_ptrs + mod->num_tracepoints,
+				tp_module_going_check_quiescent, NULL);
 			break;
 		}
 	}
@@ -501,19 +517,6 @@ static __init int init_tracepoints(void)
 __initcall(init_tracepoints);
 #endif /* CONFIG_MODULES */
 
-static void for_each_tracepoint_range(struct tracepoint * const *begin,
-		struct tracepoint * const *end,
-		void (*fct)(struct tracepoint *tp, void *priv),
-		void *priv)
-{
-	struct tracepoint * const *iter;
-
-	if (!begin)
-		return;
-	for (iter = begin; iter < end; iter++)
-		fct(*iter, priv);
-}
-
 /**
  * for_each_kernel_tracepoint - iteration on all kernel tracepoints
  * @fct: callback
-- 
2.17.1

  parent reply	other threads:[~2018-07-04  8:42 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-04  8:36 [PATCH v10 0/6] add support for relative references in special sections Ard Biesheuvel
2018-07-04  8:36 ` Ard Biesheuvel
2018-07-04  8:36 ` [PATCH v10 1/6] arch: enable relative relocations for arm64, power and x86 Ard Biesheuvel
2018-07-04  8:36   ` Ard Biesheuvel
2018-07-04  8:36 ` [PATCH v10 2/6] module: allow symbol exports to be disabled Ard Biesheuvel
2018-07-04  8:36   ` Ard Biesheuvel
2018-07-04  8:36 ` [PATCH v10 3/6] module: use relative references for __ksymtab entries Ard Biesheuvel
2018-07-04  8:36   ` Ard Biesheuvel
2018-07-04  8:36 ` [PATCH v10 4/6] init: allow initcall tables to be emitted using relative references Ard Biesheuvel
2018-07-04  8:36   ` Ard Biesheuvel
2018-07-04  8:36 ` [PATCH v10 5/6] PCI: Add support for relative addressing in quirk tables Ard Biesheuvel
2018-07-04  8:36   ` Ard Biesheuvel
2018-07-04  8:36 ` Ard Biesheuvel [this message]
2018-07-04  8:36   ` [PATCH v10 6/6] kernel: tracepoints: add support for relative references Ard Biesheuvel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180704083651.24360-7-ard.biesheuvel@linaro.org \
    --to=ard.biesheuvel@linaro.org \
    --cc=akpm@linux-foundation.org \
    --cc=arnd@arndb.de \
    --cc=benh@kernel.crashing.org \
    --cc=bhelgaas@google.com \
    --cc=catalin.marinas@arm.com \
    --cc=jeyu@kernel.org \
    --cc=jmorris@namei.org \
    --cc=jpoimboe@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mingo@redhat.com \
    --cc=mpe@ellerman.id.au \
    --cc=nico@linaro.org \
    --cc=paulus@samba.org \
    --cc=pmladek@suse.com \
    --cc=rostedt@goodmis.org \
    --cc=serge@hallyn.com \
    --cc=sergey.senozhatsky@gmail.com \
    --cc=tglx@linutronix.de \
    --cc=thgarnie@google.com \
    --cc=torvalds@linux-foundation.org \
    --cc=will.deacon@arm.com \
    --cc=x86@kernel.org \
    --subject='Re: [PATCH v10 6/6] kernel: tracepoints: add support for relative references' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.