linux-kernel - Re: [PATCH 08/29] x86/boot/e820: Print E820_TYPE

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Message-ID: <aAc_7Zm1PqeRmKMW@kernel.org>
Date: Tue, 22 Apr 2025 10:06:21 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org, Andy Shevchenko <andy@...nel.org>,
	Arnd Bergmann <arnd@...nel.org>, Borislav Petkov <bp@...en8.de>,
	Juergen Gross <jgross@...e.com>, "H . Peter Anvin" <hpa@...or.com>,
	Kees Cook <keescook@...omium.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Paul Menzel <pmenzel@...gen.mpg.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	David Woodhouse <dwmw@...zon.co.uk>
Subject: Re: [PATCH 08/29] x86/boot/e820: Print E820_TYPE_RAM entries as ...
 RAM entries

On Mon, Apr 21, 2025 at 08:51:48PM +0200, Ingo Molnar wrote:
> So it is a bit weird that the actual RAM entries of the E820 table
> are not actually called RAM, but 'usable':
> 
> 	BIOS-e820: [mem 0x0000000000100000-0x000000007ffdbfff]    1.9 GB usable
> 
> 'usable' is pretty passive-aggressive in that context and ambiguous,
> most E820 entries denote 'usable' address ranges - reserved ranges
> may be used by devices, or the platform.
> 
> Clarify and disambiguate this by making the boot log entry
> explicitly say 'kernel usable RAM':
> 
> 	BIOS-e820: [mem 0x0000000000100000-0x000000007ffdbfff]    1.9 GB kernel usable RAM
> 
> Signed-off-by: Ingo Molnar <mingo@...nel.org>
> Cc: Andy Shevchenko <andy@...nel.org>
> Cc: Arnd Bergmann <arnd@...nel.org>
> Cc: David Woodhouse <dwmw@...zon.co.uk>
> Cc: H. Peter Anvin <hpa@...or.com>
> Cc: Kees Cook <keescook@...omium.org>
> Cc: Linus Torvalds <torvalds@...ux-foundation.org>
> Cc: Mike Rapoport (Microsoft) <rppt@...nel.org>
> ---
>  arch/x86/kernel/e820.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
> index 8ee89962fcbf..99f997ae88dc 100644
> --- a/arch/x86/kernel/e820.c
> +++ b/arch/x86/kernel/e820.c
> @@ -187,7 +187,7 @@ void __init e820__range_add(u64 start, u64 size, enum e820_type type)
>  static void __init e820_print_type(enum e820_type type)
>  {
>  	switch (type) {
> -	case E820_TYPE_RAM:		pr_cont(" usable");			break;
> +	case E820_TYPE_RAM:		pr_cont(" kernel usable RAM");		break;
>  	case E820_TYPE_RESERVED:	pr_cont(" reserved");			break;
>  	case E820_TYPE_SOFT_RESERVED:	pr_cont(" soft reserved");		break;
>  	case E820_TYPE_ACPI:		pr_cont(" ACPI data");			break;

We have e820_type_to_string(), IMO the whole switch here can be replaced by

	pr_cont(" %s", e820_type_to_string(type));

> -- 
> 2.45.2
> 

-- 
Sincerely yours,
Mike.