MIME-Version: 1.0
In-Reply-To: <CAPeXnHsn=VBExn0haFdxqbZT-j8fXROaVe0zVLqK9ooJmev2bQ@mail.gmail.com>
References: <1428518512-13460-1-git-send-email-mjg59@coreos.com>
	<1428611100-23337-1-git-send-email-mjg59@srcf.ucam.org>
	<CAPeXnHuG6k3seK9HPYYPt=MfDt2jN2mdUhMLYye9kdZPJE-4Jg@mail.gmail.com>
	<20150512092821.GA10900@gmail.com>
	<CAPeXnHuyGPoySkF5rh01f=W7g8OiMp3cSC_D=OSR13=ixbzJ=g@mail.gmail.com>
	<CAPeXnHsn=VBExn0haFdxqbZT-j8fXROaVe0zVLqK9ooJmev2bQ@mail.gmail.com>
Date: Tue, 12 May 2015 16:41:22 -0700
Message-ID: <CAE9FiQWuei89mmkpThY-ckMut3oRj=61iWk=R7=z2XO0aTekmg@mail.gmail.com>
Subject: Re: [PATCH V2] x86: Allow built-in command line to work in early
 kernel init
From: Yinghai Lu <yinghai@kernel.org>
To: Matthew Garrett <matthew.garrett@coreos.com>
Cc: Ingo Molnar <mingo@kernel.org>, Matthew Garrett <mjg59@srcf.ucam.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Matthew Garrett <mjg59@coreos.com>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2015
Lines: 77

On Tue, May 12, 2015 at 11:42 AM, Matthew Garrett
<matthew.garrett@coreos.com> wrote:
> Ok, maybe something more like this? It even gets rid of some of the
> #ifdefs in setup.c.
>
> diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
> index 625d21b..9ddffd0 100644
> --- a/arch/x86/boot/cmdline.c
> +++ b/arch/x86/boot/cmdline.c
> @@ -12,8 +12,15 @@
>   * Simple command-line parser for early boot.
>   */
>
> +#include <asm/cmdline_append.h>
>  #include "boot.h"
>
> +#ifdef CONFIG_CMDLINE_BOOL
> +static char builtin_cmdline[] = CONFIG_CMDLINE;
> +#else
> +static char *builtin_cmdline;
> +#endif
> +
>  static inline int myisspace(u8 c)
>  {
>      return c <= ' ';    /* Close enough approximation */
> @@ -156,3 +163,38 @@ int __cmdline_find_option_bool(unsigned long
> cmdline_ptr, const char *option)
>
>      return 0;    /* Buffer overrun */
>  }
> +
> +int __cmdline_init(unsigned long cmdline_ptr, struct boot_params *params)
> +{
> +    addr_t cptr;
> +    int i = 0;
> +
> +    if (!builtin_cmdline)
> +        return 0;
> +
> +    if (!cmdline_ptr)
> +        return -1;      /* No command line */
> +
> +    set_fs(cmdline_ptr >> 4);
> +    cptr = cmdline_ptr & 0xf;
> +
> +    if (append_cmdline) {
> +        while (cptr < 0x10000) {
> +            char c = rdfs8(cptr);
> +            if (!c) {
> +                wrfs8(' ', cptr++);
> +                break;
> +            }
> +            cptr++;
> +        }
> +    }
> +
> +    while (builtin_cmdline[i] && cptr < 0xffff)
> +        wrfs8(builtin_cmdline[i++], cptr++);
> +
> +    wrfs8('\0', cptr);
> +
> +    params->setup_flags |= SETUP_CMDLINE_APPENDED;
> +
> +    return 0;
> +}

You can not assume that you can use buffer after cmd_line from bootloader
blindly.

Thanks

Yinghai
--
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/