Re: [PATCH] bootup: Add built-in kernel command line for x86 (v2)
* Tim Bird <[EMAIL PROTECTED]> wrote: > + To compile command line arguments into the kernel, > + set this option to 'Y', then fill in the FYI, this tab-to-space whitespace error caused this build failure in -tip testing: arch/x86/Kconfig:1500: unknown option "set" arch/x86/Kconfig:1501: unknown option "the" arch/x86/Kconfig:1503: unknown option "Systems" arch/x86/Kconfig:1504: unknown option "should" arch/x86/Kconfig:1519: unknown option "In" arch/x86/Kconfig:1520: unknown option "by" arch/x86/Kconfig:1521: unknown option "file" i fixed it up. This line was broken too: > + In most cases, the command line (whether built-in or provided Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86 (v2)
* Tim Bird <[EMAIL PROTECTED]> wrote: > Allow x86 to support a built-in kernel command line. The built-in > command line can override the one provided by the boot loader, for > those cases where the boot loader is broken or it is difficult to > change the command line in the the boot loader. > > Signed-off-by: Tim Bird <[EMAIL PROTECTED]> applied to tip/x86/commandline for v2.6.28 merging - thanks Tim! Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86 (v2)
Allow x86 to support a built-in kernel command line. The built-in
command line can override the one provided by the boot loader, for
those cases where the boot loader is broken or it is difficult
to change the command line in the the boot loader.
Signed-off-by: Tim Bird <[EMAIL PROTECTED]>
---
arch/x86/Kconfig| 45 +
arch/x86/kernel/setup.c | 16
2 files changed, 61 insertions(+), 0 deletions(-)
H. Peter Anvin wrote:
> Ingo Molnar wrote:
>> Best would be to make it really apparent in the code that nothing
>> changes if this config option is not set. Preferably there should be
>> no extra code at all in that case.
>>
>
> I would like to see this:
[...Nested ifdefs...]
OK. This version changes absolutely nothing if CONFIG_CMDLINE_BOOL is not
set (the default). Also, no space is appended even when CONFIG_CMDLINE_BOOL
is set, but the builtin string is empty. This is less sloppy all the way
around, IMHO.
Note that I use the same option names as on other arches for
this feature.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 3d0f2b6..f7bbbd7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1393,6 +1393,51 @@ config COMPAT_VDSO
If unsure, say Y.
+config CMDLINE_BOOL
+ bool "Built-in kernel command line"
+ default n
+ help
+ Allow for specifying boot arguments to the kernel at
+ build time. On some systems (e.g. embedded ones), it is
+ necessary or convenient to provide some or all of the
+ kernel boot arguments with the kernel itself (that is,
+ to not rely on the boot loader to provide them.)
+
+ To compile command line arguments into the kernel,
+ set this option to 'Y', then fill in the
+ the boot arguments in CONFIG_CMDLINE.
+
+ Systems with fully functional boot loaders (i.e. non-embedded)
+ should leave this option set to 'N'.
+
+config CMDLINE
+ string "Built-in kernel command string"
+ depends on CMDLINE_BOOL
+ default ""
+ help
+ Enter arguments here that should be compiled into the kernel
+ image and used at boot time. If the boot loader provides a
+ command line at boot time, it is appended to this string to
+ form the full kernel command line, when the system boots.
+
+ However, you can use the CONFIG_CMDLINE_OVERRIDE option to
+ change this behavior.
+
+ In most cases, the command line (whether built-in or provided
+ by the boot loader) should specify the device for the root
+ file system.
+
+config CMDLINE_OVERRIDE
+ bool "Built-in command line overrides boot loader arguments"
+ default n
+ depends on CMDLINE_BOOL
+ help
+ Set this option to 'Y' to have the kernel ignore the boot loader
+ command line, and use ONLY the built-in command line.
+
+ This is used to work around broken boot loaders. This should
+ be set to 'N' under normal conditions.
+
endmenu
config ARCH_ENABLE_MEMORY_HOTPLUG
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 2d88858..492610c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -223,6 +223,9 @@ unsigned long saved_video_mode;
#define RAMDISK_LOAD_FLAG 0x4000
static char __initdata command_line[COMMAND_LINE_SIZE];
+#ifdef CONFIG_CMDLINE_BOOL
+static char __initdata builtin_cmdline[COMMAND_LINE_SIZE] = CONFIG_CMDLINE;
+#endif
#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
struct edd edd;
@@ -665,6 +668,19 @@ void __init setup_arch(char **cmdline_p)
bss_resource.start = virt_to_phys(&__bss_start);
bss_resource.end = virt_to_phys(&__bss_stop)-1;
+#ifdef CONFIG_CMDLINE_BOOL
+#ifdef CONFIG_CMDLINE_OVERRIDE
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+#else
+ if (builtin_cmdline[0]) {
+ /* append boot loader cmdline to builtin */
+ strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
+ strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ }
+#endif
+#endif
+
strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
*cmdline_p = command_line;
--
1.5.6
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Re: [PATCH] bootup: Add built-in kernel command line for x86
H. Peter Anvin wrote:
> Ingo Molnar wrote:
>> * Tim Bird <[EMAIL PROTECTED]> wrote:
>>
>>> Add support for a built-in command line for x86 architectures. The
>>> Kconfig help gives the major rationale for this addition.
>>
>> i have actually used a local hack quite similar to this to inject boot
>> options into bzImages via randconfig - so i would find this feature
>> rather useful.
>>
>> a small observation:
>>
>>> +/* append boot loader cmdline to builtin, unless builtin
>>> overrides it */
>>> +if (builtin_cmdline[0] != '!') {
>>> +strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
>>> +strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
>>> +strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
>>> +} else {
>>> +strlcpy(boot_command_line, &builtin_cmdline[1],
>>> +COMMAND_LINE_SIZE);
>>> +}
>>
>> the default branch changes existing command lines slightly: it appends
>> a space to them. This could break scripts that rely on the precise
>> contents of /proc/cmdline output. (i have some - they are arguably dodgy)
Yeah, I wasn't too comfortable with that.
>> Best would be to make it really apparent in the code that nothing
>> changes if this config option is not set. Preferably there should be
>> no extra code at all in that case.
Agreed.
>
> I would like to see this:
>
> #ifdef CONFIG_BUILTIN_CMDLINE
> # ifdef CONFIG_BUILTIN_CMDLINE_OVERRIDE
> strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
> # else
> if (boot_command_line) {
> strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
> strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> }
> # endif
> #endif
You missed copying builtin_cmdline back to boot_command_line, but
in general this looks OK to me. If nobody objects to the ifdef
multiplicity, I'll work up a version tomorrow for review. (Sorry,
I'm a bit swamped today.)
-- Tim
=
Tim Bird
Architecture Group Chair, CE Linux Forum
Senior Staff Engineer, Sony Corporation of America
=
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Re: [PATCH] bootup: Add built-in kernel command line for x86
Ingo Molnar wrote:
* Tim Bird <[EMAIL PROTECTED]> wrote:
Add support for a built-in command line for x86 architectures. The
Kconfig help gives the major rationale for this addition.
i have actually used a local hack quite similar to this to inject boot
options into bzImages via randconfig - so i would find this feature
rather useful.
a small observation:
+ /* append boot loader cmdline to builtin, unless builtin overrides it */
+ if (builtin_cmdline[0] != '!') {
+ strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
+ strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ } else {
+ strlcpy(boot_command_line, &builtin_cmdline[1],
+ COMMAND_LINE_SIZE);
+ }
the default branch changes existing command lines slightly: it appends a
space to them. This could break scripts that rely on the precise
contents of /proc/cmdline output. (i have some - they are arguably
dodgy)
Best would be to make it really apparent in the code that nothing
changes if this config option is not set. Preferably there should be no
extra code at all in that case.
I would like to see this:
#ifdef CONFIG_BUILTIN_CMDLINE
# ifdef CONFIG_BUILTIN_CMDLINE_OVERRIDE
strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
# else
if (boot_command_line) {
strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
}
# endif
#endif
-hpa
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Re: [PATCH] bootup: Add built-in kernel command line for x86
* Tim Bird <[EMAIL PROTECTED]> wrote:
> Add support for a built-in command line for x86 architectures. The
> Kconfig help gives the major rationale for this addition.
i have actually used a local hack quite similar to this to inject boot
options into bzImages via randconfig - so i would find this feature
rather useful.
a small observation:
> + /* append boot loader cmdline to builtin, unless builtin overrides it */
> + if (builtin_cmdline[0] != '!') {
> + strlcat(builtin_cmdline, " ", COMMAND_LINE_SIZE);
> + strlcat(builtin_cmdline, boot_command_line, COMMAND_LINE_SIZE);
> + strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
> + } else {
> + strlcpy(boot_command_line, &builtin_cmdline[1],
> + COMMAND_LINE_SIZE);
> + }
the default branch changes existing command lines slightly: it appends a
space to them. This could break scripts that rely on the precise
contents of /proc/cmdline output. (i have some - they are arguably
dodgy)
Best would be to make it really apparent in the code that nothing
changes if this config option is not set. Preferably there should be no
extra code at all in that case.
Ingo
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Re: [PATCH] bootup: Add built-in kernel command line for x86
Tim Bird wrote: CONFIG_CMDLINE_OVERRIDE is probably more palatable to other architectures. I'd be OK implementing it with an option, rather than a magic char. I was trying to avoid adding too many options, since many kernel developers prefer fewer options where possible. But the magic char makes the code less straightforward. If we ever move towards supporting both prefix and suffice splicing (or even complicated in-the-middle splicing), then the magic char is easier to develop into that. But so far, I can only come up with reasonable cases for append and override, and I don't want to add superfluous handling for non-existent use cases. I think I agree, and the override option would make it easier to make generic. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
Matt Mackall wrote: On Wed, 2008-08-06 at 15:48 -0700, H. Peter Anvin wrote: Tim Bird wrote: One difficulty is that the other arches' command lines are not currently "broken", so there's no real incentive to change them. The only thing novel thing I'm adding here is the addition of the leading '!' to allow for an override. This is needed in some x86 cases I'm familiar with, but I've haven't seen any cases where it would be useful for other arches. (not to say they don't exist - I just haven't seen them.) Note that it could just as easily be done with a CONFIG_CMDLINE_OVERRIDE option, since the initial reason for a magic character was to be able to provide both prefix and suffix splicing. You're right, I had forgotten about the suffix splicing and my brain is a bit foggy on what motivated it. Well, prefix = bootloader overrides; suffix = builtin overrides. CONFIG_CMDLINE_OVERRIDE is probably more palatable to other architectures. Yes, though I doubt we're in danger of introducing any real backwards compatibility issues with the magic '!' at the beginning. Well, it does if we want to make this a generic feature, which I believe we should. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
H. Peter Anvin wrote: > Tim Bird wrote: >> The only thing novel thing I'm adding here is the addition of >> the leading '!' to allow for an override. This is needed >> in some x86 cases I'm familiar with, but I've haven't seen >> any cases where it would be useful for other arches. >> (not to say they don't exist - I just haven't seen them.) >> > > Note that it could just as easily be done with a CONFIG_CMDLINE_OVERRIDE > option, since the initial reason for a magic character was to be able to > provide both prefix and suffix splicing. Agreed. > > CONFIG_CMDLINE_OVERRIDE is probably more palatable to other architectures. I'd be OK implementing it with an option, rather than a magic char. I was trying to avoid adding too many options, since many kernel developers prefer fewer options where possible. But the magic char makes the code less straightforward. If we ever move towards supporting both prefix and suffice splicing (or even complicated in-the-middle splicing), then the magic char is easier to develop into that. But so far, I can only come up with reasonable cases for append and override, and I don't want to add superfluous handling for non-existent use cases. -- Tim = Tim Bird Architecture Group Chair, CE Linux Forum Senior Staff Engineer, Sony Corporation of America = -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
On Wed, 2008-08-06 at 15:48 -0700, H. Peter Anvin wrote: > Tim Bird wrote: > > > > One difficulty is that the other arches' command lines > > are not currently "broken", so there's no real incentive > > to change them. > > > > The only thing novel thing I'm adding here is the addition of > > the leading '!' to allow for an override. This is needed > > in some x86 cases I'm familiar with, but I've haven't seen > > any cases where it would be useful for other arches. > > (not to say they don't exist - I just haven't seen them.) > > > > Note that it could just as easily be done with a CONFIG_CMDLINE_OVERRIDE > option, since the initial reason for a magic character was to be able to > provide both prefix and suffix splicing. You're right, I had forgotten about the suffix splicing and my brain is a bit foggy on what motivated it. > CONFIG_CMDLINE_OVERRIDE is probably more palatable to other architectures. Yes, though I doubt we're in danger of introducing any real backwards compatibility issues with the magic '!' at the beginning. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
On Wed, 2008-08-06 at 15:31 -0700, Tim Bird wrote: > Matt Mackall wrote: > > On Wed, 2008-08-06 at 14:31 -0700, Tim Bird wrote: > >> The default behavior is to append the boot loader string > >> to this one. However, there is a mechanism (leading '!') > >> to force the built-in string to override the boot loader > >> string. > > > > Nice solution. > > > > Where is this relative to early boot option checking? > > parse_early_param() is right AFTER this in the x86 setup_arch() > function (in arch/x86/kernel/setup.c). All the other command-line > handling I could find is after this in init/main.c:start_kernel(). Ok, there are a couple weird outliers outside of that still, but that should make most people satisfied. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
Tim Bird wrote: One difficulty is that the other arches' command lines are not currently "broken", so there's no real incentive to change them. The only thing novel thing I'm adding here is the addition of the leading '!' to allow for an override. This is needed in some x86 cases I'm familiar with, but I've haven't seen any cases where it would be useful for other arches. (not to say they don't exist - I just haven't seen them.) Note that it could just as easily be done with a CONFIG_CMDLINE_OVERRIDE option, since the initial reason for a magic character was to be able to provide both prefix and suffix splicing. CONFIG_CMDLINE_OVERRIDE is probably more palatable to other architectures. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
Matt Mackall wrote: > On Wed, 2008-08-06 at 14:31 -0700, Tim Bird wrote: >> The default behavior is to append the boot loader string >> to this one. However, there is a mechanism (leading '!') >> to force the built-in string to override the boot loader >> string. > > Nice solution. > > Where is this relative to early boot option checking? parse_early_param() is right AFTER this in the x86 setup_arch() function (in arch/x86/kernel/setup.c). All the other command-line handling I could find is after this in init/main.c:start_kernel(). There is some stuff earlier in the setup_arch() routine about boot_params, but that looks like it's related to the old(?) binary data points you can jam into the kernel image. (That is, it doesn't look like it's related to the command line handling). -- Tim = Tim Bird Architecture Group Chair, CE Linux Forum Senior Staff Engineer, Sony Corporation of America = -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
Robert Schwebel wrote: > On Wed, Aug 06, 2008 at 02:31:48PM -0700, Tim Bird wrote: >> Add support for a built-in command line for x86 architectures. >> The Kconfig help gives the major rationale for this addition. > > If this feature is desired on all architectures, shouldn't it go out of > arch/? Different arches handle their command lines differently, but with some elbow grease (and some buy-in from the different arch maintainers), we could try unifying the approach here. One difficulty is that the other arches' command lines are not currently "broken", so there's no real incentive to change them. The only thing novel thing I'm adding here is the addition of the leading '!' to allow for an override. This is needed in some x86 cases I'm familiar with, but I've haven't seen any cases where it would be useful for other arches. (not to say they don't exist - I just haven't seen them.) -- Tim = Tim Bird Architecture Group Chair, CE Linux Forum Senior Staff Engineer, Sony Corporation of America = -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
On Wed, 2008-08-06 at 14:31 -0700, Tim Bird wrote: > The default behavior is to append the boot loader string > to this one. However, there is a mechanism (leading '!') > to force the built-in string to override the boot loader > string. Nice solution. Where is this relative to early boot option checking? -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] bootup: Add built-in kernel command line for x86
On Wed, Aug 06, 2008 at 02:31:48PM -0700, Tim Bird wrote: > Add support for a built-in command line for x86 architectures. > The Kconfig help gives the major rationale for this addition. If this feature is desired on all architectures, shouldn't it go out of arch/? rsc -- Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de Pengutronix - Linux Solutions for Science and Industry Handelsregister: Amtsgericht Hildesheim, HRA 2686 Hannoversche Str. 2, 31134 Hildesheim, Germany Phone: +49-5121-206917-0 | Fax: +49-5121-206917-9 -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
