Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755737AbYFCJ1x (ORCPT ); Tue, 3 Jun 2008 05:27:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752336AbYFCJ1n (ORCPT ); Tue, 3 Jun 2008 05:27:43 -0400 Received: from hellhawk.shadowen.org ([80.68.90.175]:1257 "EHLO hellhawk.shadowen.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752284AbYFCJ1m (ORCPT ); Tue, 3 Jun 2008 05:27:42 -0400 From: Andy Whitcroft To: Andrew Morton Cc: David Brownell , pavel@suse.cz, linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, mingo@elte.hu Subject: [PATCH] add a printk_init variant storing format strings in __initdata References: <20080529162257.03426e48.akpm@linux-foundation.org> InReply-To: <20080529162257.03426e48.akpm@linux-foundation.org> Date: Tue, 3 Jun 2008 10:27:32 +0100 Message-Id: <1212485252.0@pinky> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3219 Lines: 84 [As gcc seems unable to help us out selecting the appropriate data segment for the code, how about we did something like this?] When using printk from __init functions it would be desirable to place the printk format strings in __initdata. Add a printk_init() variant which does this. This printk_init() is necessarily a #define so that we can declare the format string in static scope and mark it __initdata. We then call a newly introduced __printk_init() variant which is identicle to printk() but marked __init itself. By ensuring that an __init variant of printk is used we get proper section violation warnings when this is used incorrectly: WARNING: vmlinux.o(.text+0x3): Section mismatch in reference from the function something() to the variable .init.data:__printk_init_fmt.31426 The function something() references the variable __initdata __printk_init_fmt.31426. This is often because something lacks a __initdata annotation or the annotation of __printk_init_fmt.31426 is wrong. Note I have followed printk's pattern for __cold annotations. Signed-off-by: Andy Whitcroft --- include/linux/kernel.h | 10 ++++++++++ kernel/printk.c | 12 ++++++++++++ 2 files changed, 22 insertions(+), 0 deletions(-) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 792bf0a..7754196 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -180,6 +180,13 @@ struct pid; extern struct pid *session_of_pgrp(struct pid *pgrp); #ifdef CONFIG_PRINTK +#define printk_init(fmt, args...) \ +do { \ + static char __printk_init_fmt[] __initdata = fmt; \ + __printk_init(__printk_init_fmt, ##args); \ +} while (0) +asmlinkage int __printk_init(const char * fmt, ...) + __attribute__ ((format (printf, 1, 2))) __cold; asmlinkage int vprintk(const char *fmt, va_list args) __attribute__ ((format (printf, 1, 0))); asmlinkage int printk(const char * fmt, ...) @@ -196,6 +203,9 @@ extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst); extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); #else +asmlinkage int printk_init(const char * fmt, ...) + __attribute__ ((format (printf, 1, 2))) __cold; +static inline int __cold printk_init(const char *s, ...) { return 0; } static inline int vprintk(const char *s, va_list args) __attribute__ ((format (printf, 1, 0))); static inline int vprintk(const char *s, va_list args) { return 0; } diff --git a/kernel/printk.c b/kernel/printk.c index 8fb01c3..992a5c0 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -616,6 +616,18 @@ asmlinkage int printk(const char *fmt, ...) return r; } +asmlinkage __init int __printk_init(const char *fmt, ...) +{ + va_list args; + int r; + + va_start(args, fmt); + r = vprintk(fmt, args); + va_end(args); + + return r; +} + /* cpu currently holding logbuf_lock */ static volatile unsigned int printk_cpu = UINT_MAX; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/