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From: Joerg Roedel <jroedel@suse.de>
To: Arvind Sankar <nivedita@alum.mit.edu>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/5] x86/boot: Initialize boot_params in startup code
Date: Thu, 8 Oct 2020 11:04:20 +0200	[thread overview]
Message-ID: <20201008090420.GD3209@suse.de> (raw)
In-Reply-To: <20201007195351.776555-2-nivedita@alum.mit.edu>

On Wed, Oct 07, 2020 at 03:53:47PM -0400, Arvind Sankar wrote:
> Save the boot_params pointer passed in by the bootloader in
> startup_32/64. This avoids having to initialize it in two different
> places in C code, and having to preserve SI through the early assembly
> code.
> 
> Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>

Nice cleanup!

>  /*
>   * Jump to the extracted kernel.
>   */
> -	xorl	%ebx, %ebx
> +	movl	boot_params@GOTOFF(%ebx), %esi
>  	jmp	*%eax
>  SYM_FUNC_END(.Lrelocated)
>  
> @@ -209,6 +208,8 @@ SYM_DATA_START_LOCAL(gdt)
>  	.quad	0x00cf92000000ffff	/* __KERNEL_DS */
>  SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)
>  
> +SYM_DATA(boot_params, .long 0)
> +

You should add a comment here that boot_params needs to be in the .data
section because in .bss it would get zeroed out again later. Same
applies to the 64bit version of this.

With that changed:

Reviewed-by: Joerg Roedel <jroedel@suse.de>


  reply	other threads:[~2020-10-08  9:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07 19:53 [PATCH 0/5] Couple of bugfixes to sev-es series Arvind Sankar
2020-10-07 19:53 ` [PATCH 1/5] x86/boot: Initialize boot_params in startup code Arvind Sankar
2020-10-08  9:04   ` Joerg Roedel [this message]
2020-10-08 13:44     ` Arvind Sankar
2020-10-07 19:53 ` [PATCH 2/5] x86/boot: Move get_cmd_line_ptr() and COMMAND_LINE_SIZE into misc.h Arvind Sankar
2020-10-08  9:11   ` Joerg Roedel
2020-10-08  9:30   ` Borislav Petkov
2020-10-08 13:47     ` Arvind Sankar
2020-10-08 15:10       ` Borislav Petkov
2020-10-08 15:30         ` Arvind Sankar
2020-10-08 16:16           ` Borislav Petkov
2020-10-07 19:53 ` [PATCH 3/5] x86/boot/64: Change add_identity_map() to take size for ease of use Arvind Sankar
2020-10-08  9:14   ` Joerg Roedel
2020-10-08 13:49     ` Arvind Sankar
2020-10-07 19:53 ` [PATCH 4/5] x86/boot/64: Explicitly map boot_params and command line Arvind Sankar
2020-10-08  9:17   ` Joerg Roedel
2020-10-08  9:48   ` Joerg Roedel
2020-10-08 13:57     ` Arvind Sankar
2020-10-07 19:53 ` [PATCH 5/5] x86/head/64: Disable stack protection for head$(BITS).o Arvind Sankar
2020-10-08  8:42   ` Joerg Roedel
2020-10-08 14:52     ` Arvind Sankar

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