linux-kernel - Re: [PATCH] x86: move parse_early_param to earlier code for add_efi

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Date:   Fri, 15 Dec 2017 15:18:22 +0000
From:   Matt Fleming <matt@...eblueprint.co.uk>
To:     Dave Young <dyoung@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-efi@...r.kernel.org,
        mingo@...nel.org, ard.biesheuvel@...aro.org
Subject: Re: [PATCH] x86: move parse_early_param to earlier code for
 add_efi_memmap

On Thu, 14 Dec, at 06:41:19PM, Dave Young wrote:
> On 11/30/17 at 01:23pm, Dave Young wrote:
> > 'add_efi_memmap' is an early param, but do_add_efi_memmap() has no
> > chance to run because the code path is before parse_early_param().
> > I believe it worked when the param was introduced but probably later
> > some other changes caused the wrong order and nobody noticed it.
> > 
> > Move parse_early_param before efi_memblock_x86_reserve_range to fix
> > this.
> > 
> > Signed-off-by: Dave Young <dyoung@...hat.com>
> > ---
> >  arch/x86/kernel/setup.c |   55 ++++++++++++++++++++++++------------------------
> >  1 file changed, 28 insertions(+), 27 deletions(-)
> > 
> > --- linux-x86.orig/arch/x86/kernel/setup.c
> > +++ linux-x86/arch/x86/kernel/setup.c
> > @@ -897,6 +897,34 @@ void __init setup_arch(char **cmdline_p)
> >  	rd_prompt = ((boot_params.hdr.ram_size & RAMDISK_PROMPT_FLAG) != 0);
> >  	rd_doload = ((boot_params.hdr.ram_size & RAMDISK_LOAD_FLAG) != 0);
> >  #endif
> > +
> > +#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;
> > +
> > +	/*
> > +	 * x86_configure_nx() is called before parse_early_param() to detect
> > +	 * whether hardware doesn't support NX (so that the early EHCI debug
> > +	 * console setup can safely call set_fixmap()). It may then be called
> > +	 * again from within noexec_setup() during parsing early parameters
> > +	 * to honor the respective command line option.
> > +	 */
> > +	x86_configure_nx();
> > +
> > +	parse_early_param();
> > +
> >  #ifdef CONFIG_EFI
> >  	if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
> >  		     EFI32_LOADER_SIGNATURE, 4)) {
> > @@ -935,33 +963,6 @@ void __init setup_arch(char **cmdline_p)
> >  	bss_resource.start = __pa_symbol(__bss_start);
> >  	bss_resource.end = __pa_symbol(__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;
> > -
> > -	/*
> > -	 * x86_configure_nx() is called before parse_early_param() to detect
> > -	 * whether hardware doesn't support NX (so that the early EHCI debug
> > -	 * console setup can safely call set_fixmap()). It may then be called
> > -	 * again from within noexec_setup() during parsing early parameters
> > -	 * to honor the respective command line option.
> > -	 */
> > -	x86_configure_nx();
> > -
> > -	parse_early_param();
> > -
> >  #ifdef CONFIG_MEMORY_HOTPLUG
> >  	/*
> >  	 * Memory used by the kernel cannot be hot-removed because Linux
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-efi" in
> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> Ping for review..
> 
> Another way is move "efi_memblock_x86_reserve_range" to later code
> Maybe below is better?
> 
> ---
>  arch/x86/kernel/setup.c |    5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> --- linux-x86.orig/arch/x86/kernel/setup.c
> +++ linux-x86/arch/x86/kernel/setup.c
> @@ -906,9 +906,6 @@ void __init setup_arch(char **cmdline_p)
>  		set_bit(EFI_BOOT, &efi.flags);
>  		set_bit(EFI_64BIT, &efi.flags);
>  	}
> -
> -	if (efi_enabled(EFI_BOOT))
> -		efi_memblock_x86_reserve_range();
>  #endif
>  
>  	x86_init.oem.arch_setup();
> @@ -962,6 +959,8 @@ void __init setup_arch(char **cmdline_p)
>  
>  	parse_early_param();
>  
> +	if (efi_enabled(EFI_BOOT))
> +		efi_memblock_x86_reserve_range();
>  #ifdef CONFIG_MEMORY_HOTPLUG
>  	/*
>  	 * Memory used by the kernel cannot be hot-removed because Linux
> 

I prefer this version. Please re-send a full patch and update the
subject line to include the "fix" somewhere; it wasn't obvious to me
from the start that this is a bug fix.