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[PATCH] clean up kernel messages 

Arrange for all kernel printks to be no-ops.  Only available if
CONFIG_EMBEDDED.

This patch saves about 375k on my laptop config and nearly 100k on minimal
configs.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Matt Mackall 2005-05-01 08:59:02 -07:00 committed by Linus Torvalds
parent cd7619d6bf
commit d59745ce3e
4 changed files with 43 additions and 6 deletions
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2
arch/i386/kernel/head.S
View File

@ -380,6 +380,7 @@ rp_sidt:
ALIGN
ignore_int:
cld
#ifdef CONFIG_PRINTK
pushl %eax
pushl %ecx
pushl %edx
@ -400,6 +401,7 @@ ignore_int:
popl %edx
popl %ecx
popl %eax
#endif
iret
/*

9
include/linux/kernel.h
View File

@ -115,10 +115,19 @@ extern int __kernel_text_address(unsigned long addr);
extern int kernel_text_address(unsigned long addr);
extern int session_of_pgrp(int pgrp);
#ifdef CONFIG_PRINTK
asmlinkage int vprintk(const char *fmt, va_list args)
__attribute__ ((format (printf, 1, 0)));
asmlinkage int printk(const char * fmt, ...)
__attribute__ ((format (printf, 1, 2)));
#else
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; }
static inline int printk(const char *s, ...)
__attribute__ ((format (printf, 1, 2)));
static inline int printk(const char *s, ...) { return 0; }
#endif
unsigned long int_sqrt(unsigned long);

11
init/Kconfig
View File

@ -275,6 +275,17 @@ config KALLSYMS_EXTRA_PASS
reported. KALLSYMS_EXTRA_PASS is only a temporary workaround while
you wait for kallsyms to be fixed.
config PRINTK
default y
bool "Enable support for printk" if EMBEDDED
help
This option enables normal printk support. Removing it
eliminates most of the message strings from the kernel image
and makes the kernel more or less silent. As this makes it
very difficult to diagnose system problems, saying N here is
strongly discouraged.
config BUG
bool "BUG() support" if EMBEDDED
default y

27
kernel/printk.c
View File

@ -85,10 +85,6 @@ static int console_locked;
*/
static DEFINE_SPINLOCK(logbuf_lock);
static char __log_buf[__LOG_BUF_LEN];
static char *log_buf = __log_buf;
static int log_buf_len = __LOG_BUF_LEN;
#define LOG_BUF_MASK (log_buf_len-1)
#define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
@ -99,7 +95,6 @@ static int log_buf_len = __LOG_BUF_LEN;
static unsigned long log_start; /* Index into log_buf: next char to be read by syslog() */
static unsigned long con_start; /* Index into log_buf: next char to be sent to consoles */
static unsigned long log_end; /* Index into log_buf: most-recently-written-char + 1 */
static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
/*
* Array of consoles built from command line options (console=)
@ -120,6 +115,13 @@ static int preferred_console = -1;
/* Flag: console code may call schedule() */
static int console_may_schedule;
#ifdef CONFIG_PRINTK
static char __log_buf[__LOG_BUF_LEN];
static char *log_buf = __log_buf;
static int log_buf_len = __LOG_BUF_LEN;
static unsigned long logged_chars; /* Number of chars produced since last read+clear operation */
/*
* Setup a list of consoles. Called from init/main.c
*/
@ -535,6 +537,7 @@ __setup("time", printk_time_setup);
* then changes console_loglevel may break. This is because console_loglevel
* is inspected when the actual printing occurs.
*/
asmlinkage int printk(const char *fmt, ...)
{
va_list args;
@ -655,6 +658,18 @@ asmlinkage int vprintk(const char *fmt, va_list args)
EXPORT_SYMBOL(printk);
EXPORT_SYMBOL(vprintk);
#else
asmlinkage long sys_syslog(int type, char __user * buf, int len)
{
return 0;
}
int do_syslog(int type, char __user * buf, int len) { return 0; }
static void call_console_drivers(unsigned long start, unsigned long end) {}
#endif
/**
* acquire_console_sem - lock the console system for exclusive use.
*
@ -931,7 +946,7 @@ int unregister_console(struct console * console)
return res;
}
EXPORT_SYMBOL(unregister_console);
/**
* tty_write_message - write a message to a certain tty, not just the console.
*