diff options
authorAlon Bar-Lev <alon.barlev@gmail.com>2007-02-12 00:53:52 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-12 09:48:37 -0800
commit30d7e0d466b3ac0b5ef77e4062bf9385f0d72270 (patch)
parent[PATCH] sched: avoid div in rebalance_tick (diff)
[PATCH] Dynamic kernel command-line: common
Current implementation stores a static command-line buffer allocated to COMMAND_LINE_SIZE size. Most architectures stores two copies of this buffer, one for future reference and one for parameter parsing. Current kernel command-line size for most architecture is much too small for module parameters, video settings, initramfs paramters and much more. The problem is that setting COMMAND_LINE_SIZE to a grater value, allocates static buffers. In order to allow a greater command-line size, these buffers should be dynamically allocated or marked as init disposable buffers, so unused memory can be released. This patch renames the static saved_command_line variable into boot_command_line adding __initdata attribute, so that it can be disposed after initialization. This rename is required so applications that use saved_command_line will not be affected by this change. It reintroduces saved_command_line as dynamically allocated buffer to match the data in boot_command_line. It also mark secondary command-line buffer as __initdata, and copies it to dynamically allocated static_command_line buffer components may hold reference to it after initialization. This patch is for linux-2.6.20-rc4-mm1 and is divided to target each architecture. I could not check this in any architecture so please forgive me if I got it wrong. The per-architecture modification is very simple, use boot_command_line in place of saved_command_line. The common code is the change into dynamic command-line. This patch: 1. Rename saved_command_line into boot_command_line, mark as init disposable. 2. Add dynamic allocated saved_command_line. 3. Add dynamic allocated static_command_line. 4. During startup copy: boot_command_line into saved_command_line. arch command_line into static_command_line. 5. Parse static_command_line and not arch command_line, so arch command_line may be freed. Signed-off-by: Alon Bar-Lev <alon.barlev@gmail.com> Cc: Andi Kleen <ak@muc.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ian Molton <spyro@f2s.com> Cc: Mikael Starvik <starvik@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp> Cc: Richard Curnow <rc@rc0.org.uk> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp> Cc: Chris Zankel <chris@zankel.net> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2 files changed, 27 insertions, 7 deletions
diff --git a/include/linux/init.h b/include/linux/init.h
index c65f5107d512..e290a010e3f2 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -67,7 +67,8 @@ extern initcall_t __con_initcall_start[], __con_initcall_end[];
extern initcall_t __security_initcall_start[], __security_initcall_end[];
/* Defined in init/main.c */
-extern char saved_command_line[];
+extern char __initdata boot_command_line[];
+extern char *saved_command_line;
extern unsigned int reset_devices;
/* used by init/main.c */
@@ -164,7 +165,7 @@ struct obs_kernel_param {
#define early_param(str, fn) \
__setup_param(str, fn, fn, 1)
-/* Relies on saved_command_line being set */
+/* Relies on boot_command_line being set */
void __init parse_early_param(void);
#endif /* __ASSEMBLY__ */
diff --git a/init/main.c b/init/main.c
index 4e88bddfbebf..4e9e92bb2b89 100644
--- a/init/main.c
+++ b/init/main.c
@@ -121,8 +121,12 @@ extern void time_init(void);
void (*late_time_init)(void);
extern void softirq_init(void);
-/* Untouched command line (eg. for /proc) saved by arch-specific code. */
-char saved_command_line[COMMAND_LINE_SIZE];
+/* Untouched command line saved by arch-specific code. */
+char __initdata boot_command_line[COMMAND_LINE_SIZE];
+/* Untouched saved command line (eg. for /proc) */
+char *saved_command_line;
+/* Command line for parameter parsing */
+static char *static_command_line;
static char *execute_command;
static char *ramdisk_execute_command;
@@ -400,6 +404,20 @@ static void __init smp_init(void)
+ * We need to store the untouched command line for future reference.
+ * We also need to store the touched command line since the parameter
+ * parsing is performed in place, and we should allow a component to
+ * store reference of name/value for future reference.
+ */
+static void __init setup_command_line(char *command_line)
+ saved_command_line = alloc_bootmem(strlen (boot_command_line)+1);
+ static_command_line = alloc_bootmem(strlen (command_line)+1);
+ strcpy (saved_command_line, boot_command_line);
+ strcpy (static_command_line, command_line);
* We need to finalize in a non-__init function or else race conditions
* between the root thread and the init thread may cause start_kernel to
* be reaped by free_initmem before the root thread has proceeded to
@@ -453,7 +471,7 @@ void __init parse_early_param(void)
/* All fall through to do_early_param. */
- strlcpy(tmp_cmdline, saved_command_line, COMMAND_LINE_SIZE);
+ strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
parse_args("early options", tmp_cmdline, NULL, 0, do_early_param);
done = 1;
@@ -503,6 +521,7 @@ asmlinkage void __init start_kernel(void)
+ setup_command_line(command_line);
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */
@@ -520,9 +539,9 @@ asmlinkage void __init start_kernel(void)
- printk(KERN_NOTICE "Kernel command line: %s\n", saved_command_line);
+ printk(KERN_NOTICE "Kernel command line: %s\n", boot_command_line);
- parse_args("Booting kernel", command_line, __start___param,
+ parse_args("Booting kernel", static_command_line, __start___param,
__stop___param - __start___param,
if (!irqs_disabled()) {