core_param: call these really, really early.

core_param: call these really, really early.

[Rusty Russell]

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As soon as we have command line, so even before early_param.  Theyjust set vars, so it makes sense to do them as early as possible.
This allows them to replace early_param, and fixes a bug in the newcpu_alloc implementation patches which was a complete PITA to find.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>--- include/asm-generic/vmlinux.lds.h |    3 +++ include/linux/moduleparam.h       |   26 ++++++++++++++++---------- init/main.c                       |   25 ++++++++++++++++++++++++- kernel/params.c                   |   20 ++++++++++---------- 4 files changed, 53 insertions(+), 21 deletions(-)
diff -r 65aebfe44ef1 include/asm-generic/vmlinux.lds.h--- a/include/asm-generic/vmlinux.lds.h	Wed Nov 19 22:47:52 2008 +1030+++ b/include/asm-generic/vmlinux.lds.h	Wed Nov 19 23:58:08 2008 +1030@@ -213,6 +213,9 @@ 		VMLINUX_SYMBOL(__start___param) = .;			\ 		*(__param)						\ 		VMLINUX_SYMBOL(__stop___param) = .;			\+		VMLINUX_SYMBOL(__start___core_param) = .;		\+		*(__core_param)						\+		VMLINUX_SYMBOL(__stop___core_param) = .;		\ 		. = ALIGN((align));					\ 		VMLINUX_SYMBOL(__end_rodata) = .;			\ 	}								\diff -r 65aebfe44ef1 include/linux/moduleparam.h--- a/include/linux/moduleparam.h	Wed Nov 19 22:47:52 2008 +1030+++ b/include/linux/moduleparam.h	Wed Nov 19 23:58:08 2008 +1030@@ -79,7 +79,7 @@    parameters.  perm sets the visibility in sysfs: 000 means it's    not there, read bits mean it's readable, write bits mean it's    writable. */-#define __module_param_call(prefix, name, set, get, arg, perm)		\+#define __module_param_call(prefix, section, name, set, get, arg, perm)	\ 	/* Default value instead of permissions? */			\ 	static int __param_perm_check_##name __attribute__((unused)) =	\ 	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))	\@@ -87,11 +87,12 @@ 	static const char __param_str_##name[] = prefix #name;		\ 	static struct kernel_param __moduleparam_const __param_##name	\ 	__used								\-    __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \+    __attribute__ ((unused, __section__(section), aligned(sizeof(void *)))) \ 	= { __param_str_##name, perm, set, get, { arg } }  #define module_param_call(name, set, get, arg, perm)			      \-	__module_param_call(MODULE_PARAM_PREFIX, name, set, get, arg, perm)+	__module_param_call(MODULE_PARAM_PREFIX, "__param",		      \+			    name, set, get, arg, perm)  /* Helper functions: type is byte, short, ushort, int, uint, long,    ulong, charp, bool or invbool, or XXX if you define param_get_XXX,@@ -106,21 +107,22 @@  #ifndef MODULE /**- * core_param - define a historical core kernel parameter.+ * core_param - define a core kernel parameter to be set very early  * @name: the name of the cmdline and sysfs parameter (often the same as var)  * @var: the variable  * @type: the type (for param_set_##type and param_get_##type)  * @perm: visibility in sysfs  *- * core_param is just like module_param(), but cannot be modular and- * doesn't add a prefix (such as "printk.").  This is for compatibility- * with __setup(), and it makes sense as truly core parameters aren't- * tied to the particular file they're in.+ * core_param is just like module_param(), but cannot be modular,+ * doesn't add a prefix (such as "printk.") and is called insanely+ * early in boot.  This is for compatibility with __setup(), and it+ * makes sense as truly core parameters aren't tied to the particular+ * file they're in.  */ #define core_param(name, var, type, perm)				\ 	param_check_##type(name, &(var));				\-	__module_param_call("", name, param_set_##type, param_get_##type, \-			    &var, perm)+	__module_param_call("", "__core_param", name, param_set_##type, \+			    param_get_##type, &var, perm) #endif /* !MODULE */  /* Actually copy string: maxlen param is usually sizeof(string). */@@ -224,4 +226,8 @@ { } #endif +/* Created by include/asm-generic/vmlinux.lds.h */+extern struct kernel_param __start___core_param[], __stop___core_param[];+extern struct kernel_param __start___param[], __stop___param[];+ #endif /* _LINUX_MODULE_PARAMS_H */diff -r 65aebfe44ef1 init/main.c--- a/init/main.c	Wed Nov 19 22:47:52 2008 +1030+++ b/init/main.c	Wed Nov 19 23:58:08 2008 +1030@@ -256,12 +256,32 @@  early_param("loglevel", loglevel); +static bool __init is_core_param(const char *param)+{+	const struct kernel_param *i;++	for (i = __start___core_param; i < __stop___core_param; i++)+		if (strcmp(param, i->name) == 0)+			return true;+	return false;+}++/* We can ignore options not found in core params. */+static int __init unknown_core_ok(char *param, char *val)+{+	return 0;+}+ /*  * Unknown boot options get handed to init, unless they look like  * failed parameters  */ static int __init unknown_bootoption(char *param, char *val) {+	/* Already handled as a core param? */+	if (is_core_param(param))+		return 0;+ 	/* Change NUL term back to "=", to make "param" the whole string. */ 	if (val) { 		/* param=val or param="val"? */@@ -539,7 +559,6 @@ asmlinkage void __init start_kernel(void) { 	char * command_line;-	extern struct kernel_param __start___param[], __stop___param[];  	smp_setup_processor_id(); @@ -569,6 +588,10 @@ 	setup_arch(&command_line); 	mm_init_owner(&init_mm, &init_task); 	setup_command_line(command_line);+	parse_args("Core params", command_line, __start___core_param,+		   __stop___core_param - __start___core_param,+		   unknown_core_ok);+ 	unwind_setup(); 	setup_per_cpu_areas(); 	setup_nr_cpu_ids();diff -r 65aebfe44ef1 kernel/params.c--- a/kernel/params.c	Wed Nov 19 22:47:52 2008 +1030+++ b/kernel/params.c	Wed Nov 19 23:58:08 2008 +1030@@ -376,8 +376,6 @@ #define to_module_attr(n) container_of(n, struct module_attribute, attr); #define to_module_kobject(n) container_of(n, struct module_kobject, kobj); -extern struct kernel_param __start___param[], __stop___param[];- struct param_attribute { 	struct module_attribute mattr;@@ -636,15 +634,17 @@ 			continue;  		dot = strchr(kp->name, '.');-		if (!dot) {-			/* This happens for core_param() */-			strcpy(modname, "kernel");-			name_len = 0;-		} else {-			name_len = dot - kp->name + 1;-			strlcpy(modname, kp->name, name_len);-		}+		BUG_ON(!dot);+		name_len = dot - kp->name + 1;+		strlcpy(modname, kp->name, name_len); 		kernel_add_sysfs_param(modname, kp, name_len);+	}++	for (kp = __start___core_param; kp < __stop___core_param; kp++) {+		if (kp->perm == 0)+			continue;++		kernel_add_sysfs_param("kernel", kp, 0); 	} } \0ÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥

Re: core_param: call these really, really early.

[Heiko Carstens]

On Thu, Nov 20, 2008 at 01:23:41AM +1030, Rusty Russell wrote:
> As soon as we have command line, so even before early_param.  They
> just set vars, so it makes sense to do them as early as possible.
> 
> This allows them to replace early_param, and fixes a bug in the new
> cpu_alloc implementation patches which was a complete PITA to find.
> 
> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

[...]

> diff -r 65aebfe44ef1 init/main.c
> --- a/init/main.c	Wed Nov 19 22:47:52 2008 +1030
> +++ b/init/main.c	Wed Nov 19 23:58:08 2008 +1030
> @@ -569,6 +588,10 @@
>  	setup_arch(&command_line);
>  	mm_init_owner(&init_mm, &init_task);
>  	setup_command_line(command_line);
> +	parse_args("Core params", command_line, __start___core_param,
> +		   __stop___core_param - __start___core_param,
> +		   unknown_core_ok);
> +
>  	unwind_setup();
>  	setup_per_cpu_areas();
>  	setup_nr_cpu_ids();

...but setup_arch() calls parse_early_param(). So how is this earlier
than early_param?

Re: core_param: call these really, really early.

[Rusty Russell]

On Wednesday 26 November 2008 18:38:46 Heiko Carstens wrote:
> On Thu, Nov 20, 2008 at 01:23:41AM +1030, Rusty Russell wrote:
> > As soon as we have command line, so even before early_param.  They
> > just set vars, so it makes sense to do them as early as possible.
> >
> > This allows them to replace early_param, and fixes a bug in the new
> > cpu_alloc implementation patches which was a complete PITA to find.
> >
> > Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
>
> [...]
>
> > diff -r 65aebfe44ef1 init/main.c
> > --- a/init/main.c	Wed Nov 19 22:47:52 2008 +1030
> > +++ b/init/main.c	Wed Nov 19 23:58:08 2008 +1030
> > @@ -569,6 +588,10 @@
> >  	setup_arch(&command_line);
> >  	mm_init_owner(&init_mm, &init_task);
> >  	setup_command_line(command_line);
> > +	parse_args("Core params", command_line, __start___core_param,
> > +		   __stop___core_param - __start___core_param,
> > +		   unknown_core_ok);
> > +
> >  	unwind_setup();
> >  	setup_per_cpu_areas();
> >  	setup_nr_cpu_ids();
>
> ...but setup_arch() calls parse_early_param(). So how is this earlier
> than early_param?

True, I'd forgotten that most setup_arch()s call parse_early_param (there's a 
general call lower down in start_kernel).

I actually think start_kernel should take a char *params as a parameter, but 
that's a big multi-arch change I wasn't prepared to hack up just yet.

OK, now have three patches which clean up cmdline handling.  They're big :(  
Will test a little and post...

Cheers,
Rusty.