diff mbox

[v9,4/6] init: allow initcall tables to be emitted using relative references

Message ID 20180626182802.19932-5-ard.biesheuvel@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

Ard Biesheuvel June 26, 2018, 6:27 p.m. UTC 
Allow the initcall tables to be emitted using relative references that
are only half the size on 64-bit architectures and don't require fixups
at runtime on relocatable kernels.

Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/init.h   | 44 +++++++++++++++-----
 init/main.c            | 32 +++++++-------
 kernel/printk/printk.c | 16 +++----
 security/security.c    | 17 ++++----
 4 files changed, 68 insertions(+), 41 deletions(-)

Comments

James Morris June 26, 2018, 7:13 p.m. UTC | #1 
On Tue, 26 Jun 2018, Ard Biesheuvel wrote:

> Allow the initcall tables to be emitted using relative references that
> are only half the size on 64-bit architectures and don't require fixups
> at runtime on relocatable kernels.
> 
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: James Morris <jmorris@namei.org>
> Cc: "Serge E. Hallyn" <serge@hallyn.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  include/linux/init.h   | 44 +++++++++++++++-----
>  init/main.c            | 32 +++++++-------
>  kernel/printk/printk.c | 16 +++----
>  security/security.c    | 17 ++++----
>  4 files changed, 68 insertions(+), 41 deletions(-)


Acked-by: James Morris <james.morris@microsoft.com>
Sergey Senozhatsky June 27, 2018, 2:20 p.m. UTC | #2 
On (06/26/18 20:27), Ard Biesheuvel wrote:
>  /*
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 247808333ba4..688a27b0888c 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -2772,7 +2772,8 @@ EXPORT_SYMBOL(unregister_console);
>  void __init console_init(void)
>  {
>  	int ret;
> -	initcall_t *call;
> +	initcall_t call;
> +	initcall_entry_t *ce;
>  
>  	/* Setup the default TTY line discipline. */
>  	n_tty_init();
> @@ -2781,13 +2782,14 @@ void __init console_init(void)
>  	 * set up the console device so that later boot sequences can
>  	 * inform about problems etc..
>  	 */
> -	call = __con_initcall_start;
> +	ce = __con_initcall_start;
>  	trace_initcall_level("console");
> -	while (call < __con_initcall_end) {
> -		trace_initcall_start((*call));
> -		ret = (*call)();
> -		trace_initcall_finish((*call), ret);
> -		call++;
> +	while (ce < __con_initcall_end) {
> +		call = initcall_from_entry(ce);
> +		trace_initcall_start(call);
> +		ret = call();
> +		trace_initcall_finish(call, ret);
> +		ce++;
>  	}
>  }

printk bits look OK to me.
The patch set works fine on my x86_64 and does reduce the size of vmlinux.

Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

	-ss
Petr Mladek June 27, 2018, 3:22 p.m. UTC | #3 
On Tue 2018-06-26 20:27:59, Ard Biesheuvel wrote:
> Allow the initcall tables to be emitted using relative references that
> are only half the size on 64-bit architectures and don't require fixups
> at runtime on relocatable kernels.
> 
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: James Morris <jmorris@namei.org>
> Cc: "Serge E. Hallyn" <serge@hallyn.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  include/linux/init.h   | 44 +++++++++++++++-----
>  init/main.c            | 32 +++++++-------
>  kernel/printk/printk.c | 16 +++----
>  security/security.c    | 17 ++++----
>  4 files changed, 68 insertions(+), 41 deletions(-)

For the printk stuff:

Acked-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr
kernel test robot June 30, 2018, 10:16 a.m. UTC | #4 
Hi Ard,

I love your patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.18-rc2 next-20180629]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/arch-enable-relative-relocations-for-arm64-power-and-x86/20180627-025148
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.2.0 make.cross ARCH=powerpc 

All errors (new ones prefixed by >>):

   {standard input}: Assembler messages:
>> {standard input}: Error: .size expression for .discard does not evaluate to a constant

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
diff mbox

Patch

diff --git a/include/linux/init.h b/include/linux/init.h
index bc27cf03c41e..2538d176dd1f 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -116,8 +116,24 @@ 
 typedef int (*initcall_t)(void);
 typedef void (*exitcall_t)(void);
 
-extern initcall_t __con_initcall_start[], __con_initcall_end[];
-extern initcall_t __security_initcall_start[], __security_initcall_end[];
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+typedef int initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+	return offset_to_ptr(entry);
+}
+#else
+typedef initcall_t initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+	return *entry;
+}
+#endif
+
+extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
+extern initcall_entry_t __security_initcall_start[], __security_initcall_end[];
 
 /* Used for contructor calls. */
 typedef void (*ctor_fn_t)(void);
@@ -167,9 +183,20 @@  extern bool initcall_debug;
  * as KEEP() in the linker script.
  */
 
-#define __define_initcall(fn, id) \
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define ___define_initcall(fn, id, __sec)			\
+	__ADDRESSABLE(fn)					\
+	asm(".section	\"" #__sec ".init\", \"a\"	\n"	\
+	"__initcall_" #fn #id ":			\n"	\
+	    ".long	" #fn " - .			\n"	\
+	    ".previous					\n");
+#else
+#define ___define_initcall(fn, id, __sec) \
 	static initcall_t __initcall_##fn##id __used \
-	__attribute__((__section__(".initcall" #id ".init"))) = fn;
+		__attribute__((__section__(#__sec ".init"))) = fn;
+#endif
+
+#define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
 
 /*
  * Early initcalls run before initializing SMP.
@@ -208,13 +235,8 @@  extern bool initcall_debug;
 #define __exitcall(fn)						\
 	static exitcall_t __exitcall_##fn __exit_call = fn
 
-#define console_initcall(fn)					\
-	static initcall_t __initcall_##fn			\
-	__used __section(.con_initcall.init) = fn
-
-#define security_initcall(fn)					\
-	static initcall_t __initcall_##fn			\
-	__used __section(.security_initcall.init) = fn
+#define console_initcall(fn)	___define_initcall(fn,, .con_initcall)
+#define security_initcall(fn)	___define_initcall(fn,, .security_initcall)
 
 struct obs_kernel_param {
 	const char *str;
diff --git a/init/main.c b/init/main.c
index 3b4ada11ed52..e59a01f163d6 100644
--- a/init/main.c
+++ b/init/main.c
@@ -901,18 +901,18 @@  int __init_or_module do_one_initcall(initcall_t fn)
 }
 
 
-extern initcall_t __initcall_start[];
-extern initcall_t __initcall0_start[];
-extern initcall_t __initcall1_start[];
-extern initcall_t __initcall2_start[];
-extern initcall_t __initcall3_start[];
-extern initcall_t __initcall4_start[];
-extern initcall_t __initcall5_start[];
-extern initcall_t __initcall6_start[];
-extern initcall_t __initcall7_start[];
-extern initcall_t __initcall_end[];
-
-static initcall_t *initcall_levels[] __initdata = {
+extern initcall_entry_t __initcall_start[];
+extern initcall_entry_t __initcall0_start[];
+extern initcall_entry_t __initcall1_start[];
+extern initcall_entry_t __initcall2_start[];
+extern initcall_entry_t __initcall3_start[];
+extern initcall_entry_t __initcall4_start[];
+extern initcall_entry_t __initcall5_start[];
+extern initcall_entry_t __initcall6_start[];
+extern initcall_entry_t __initcall7_start[];
+extern initcall_entry_t __initcall_end[];
+
+static initcall_entry_t *initcall_levels[] __initdata = {
 	__initcall0_start,
 	__initcall1_start,
 	__initcall2_start,
@@ -938,7 +938,7 @@  static char *initcall_level_names[] __initdata = {
 
 static void __init do_initcall_level(int level)
 {
-	initcall_t *fn;
+	initcall_entry_t *fn;
 
 	strcpy(initcall_command_line, saved_command_line);
 	parse_args(initcall_level_names[level],
@@ -949,7 +949,7 @@  static void __init do_initcall_level(int level)
 
 	trace_initcall_level(initcall_level_names[level]);
 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
-		do_one_initcall(*fn);
+		do_one_initcall(initcall_from_entry(fn));
 }
 
 static void __init do_initcalls(void)
@@ -980,11 +980,11 @@  static void __init do_basic_setup(void)
 
 static void __init do_pre_smp_initcalls(void)
 {
-	initcall_t *fn;
+	initcall_entry_t *fn;
 
 	trace_initcall_level("early");
 	for (fn = __initcall_start; fn < __initcall0_start; fn++)
-		do_one_initcall(*fn);
+		do_one_initcall(initcall_from_entry(fn));
 }
 
 /*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 247808333ba4..688a27b0888c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2772,7 +2772,8 @@  EXPORT_SYMBOL(unregister_console);
 void __init console_init(void)
 {
 	int ret;
-	initcall_t *call;
+	initcall_t call;
+	initcall_entry_t *ce;
 
 	/* Setup the default TTY line discipline. */
 	n_tty_init();
@@ -2781,13 +2782,14 @@  void __init console_init(void)
 	 * set up the console device so that later boot sequences can
 	 * inform about problems etc..
 	 */
-	call = __con_initcall_start;
+	ce = __con_initcall_start;
 	trace_initcall_level("console");
-	while (call < __con_initcall_end) {
-		trace_initcall_start((*call));
-		ret = (*call)();
-		trace_initcall_finish((*call), ret);
-		call++;
+	while (ce < __con_initcall_end) {
+		call = initcall_from_entry(ce);
+		trace_initcall_start(call);
+		ret = call();
+		trace_initcall_finish(call, ret);
+		ce++;
 	}
 }
 
diff --git a/security/security.c b/security/security.c
index 68f46d849abe..1e7b1486d82a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -48,14 +48,17 @@  static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
 static void __init do_security_initcalls(void)
 {
 	int ret;
-	initcall_t *call;
-	call = __security_initcall_start;
+	initcall_t call;
+	initcall_entry_t *ce;
+
+	ce = __security_initcall_start;
 	trace_initcall_level("security");
-	while (call < __security_initcall_end) {
-		trace_initcall_start((*call));
-		ret = (*call) ();
-		trace_initcall_finish((*call), ret);
-		call++;
+	while (ce < __security_initcall_end) {
+		call = initcall_from_entry(ce);
+		trace_initcall_start(call);
+		ret = call();
+		trace_initcall_finish(call, ret);
+		ce++;
 	}
 }