linux-kernel - Re: [PATCH 10/20] x86_64: wakeup.S Remove dead code

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Message-ID: <20061118001443.GB9188@elf.ucw.cz>
Date:	Sat, 18 Nov 2006 01:14:43 +0100
From:	Pavel Machek <pavel@....cz>
To:	Vivek Goyal <vgoyal@...ibm.com>
Cc:	linux kernel mailing list <linux-kernel@...r.kernel.org>,
	Reloc Kernel List <fastboot@...ts.osdl.org>,
	ebiederm@...ssion.com, akpm@...l.org, ak@...e.de, hpa@...or.com,
	magnus.damm@...il.com, lwang@...hat.com, dzickus@...hat.com,
	rjw@...k.pl
Subject: Re: [PATCH 10/20] x86_64: wakeup.S Remove dead code

On Fri 2006-11-17 17:47:02, Vivek Goyal wrote:
> 
> 
> o Get rid of dead code in wakeup.S
> 
> o We never restore from saved_gdt, saved_idt, saved_ltd, saved_tss, saved_cr3,
>   saved_cr4, saved_cr0, real_save_gdt, saved_efer, saved_efer2. Get rid
>   of of associated code.
> 
> o Get rid of bogus_magic, bogus_31_magic and bogus_magic2. No longer being
>   used.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@...ssion.com>
> Signed-off-by: Vivek Goyal <vgoyal@...ibm.com>

ACK and thanks.

> diff -puN arch/x86_64/kernel/acpi/wakeup.S~x86_64-get-rid-of-dead-code-in-suspend-resume arch/x86_64/kernel/acpi/wakeup.S
> --- linux-2.6.19-rc6-reloc/arch/x86_64/kernel/acpi/wakeup.S~x86_64-get-rid-of-dead-code-in-suspend-resume	2006-11-17 00:09:05.000000000 -0500
> +++ linux-2.6.19-rc6-reloc-root/arch/x86_64/kernel/acpi/wakeup.S	2006-11-17 00:09:05.000000000 -0500
> @@ -258,8 +258,6 @@ gdt_48a:
>  	.word	0, 0				# gdt base (filled in later)
>  	
>  	
> -real_save_gdt:	.word 0
> -		.quad 0
>  real_magic:	.quad 0
>  video_mode:	.quad 0
>  video_flags:	.quad 0
> @@ -272,10 +270,6 @@ bogus_32_magic:
>  	movb	$0xb3,%al	;  outb %al,$0x80
>  	jmp bogus_32_magic
>  
> -bogus_31_magic:
> -	movb	$0xb1,%al	;  outb %al,$0x80
> -	jmp bogus_31_magic
> -
>  bogus_cpu:
>  	movb	$0xbc,%al	;  outb %al,$0x80
>  	jmp bogus_cpu
> @@ -346,16 +340,6 @@ check_vesaa:
>  
>  _setbada: jmp setbada
>  
> -	.code64
> -bogus_magic:
> -	movw	$0x0e00 + 'B', %ds:(0xb8018)
> -	jmp bogus_magic
> -
> -bogus_magic2:
> -	movw	$0x0e00 + '2', %ds:(0xb8018)
> -	jmp bogus_magic2
> -	
> -
>  wakeup_stack_begin:	# Stack grows down
>  
>  .org	0xff0
> @@ -373,28 +357,11 @@ ENTRY(wakeup_end)
>  #
>  # Returned address is location of code in low memory (past data and stack)
>  #
> +	.code64
>  ENTRY(acpi_copy_wakeup_routine)
>  	pushq	%rax
> -	pushq	%rcx
>  	pushq	%rdx
>  
> -	sgdt	saved_gdt
> -	sidt	saved_idt
> -	sldt	saved_ldt
> -	str	saved_tss
> -
> -	movq    %cr3, %rdx
> -	movq    %rdx, saved_cr3
> -	movq    %cr4, %rdx
> -	movq    %rdx, saved_cr4
> -	movq	%cr0, %rdx
> -	movq	%rdx, saved_cr0
> -	sgdt    real_save_gdt - wakeup_start (,%rdi)
> -	movl	$MSR_EFER, %ecx
> -	rdmsr
> -	movl	%eax, saved_efer
> -	movl	%edx, saved_efer2
> -
>  	movl	saved_video_mode, %edx
>  	movl	%edx, video_mode - wakeup_start (,%rdi)
>  	movl	acpi_video_flags, %edx
> @@ -407,17 +374,8 @@ ENTRY(acpi_copy_wakeup_routine)
>  	cmpl	$0x9abcdef0, %eax
>  	jne	bogus_32_magic
>  
> -	# make sure %cr4 is set correctly (features, etc)
> -	movl	saved_cr4 - __START_KERNEL_map, %eax
> -	movq	%rax, %cr4
> -
> -	movl	saved_cr0 - __START_KERNEL_map, %eax
> -	movq	%rax, %cr0
> -	jmp	1f		# Flush pipelines
> -1:
>  	# restore the regs we used
>  	popq	%rdx
> -	popq	%rcx
>  	popq	%rax
>  ENTRY(do_suspend_lowlevel_s4bios)
>  	ret
> @@ -512,16 +470,3 @@ ENTRY(saved_eip)	.quad	0
>  ENTRY(saved_esp)	.quad	0
>  
>  ENTRY(saved_magic)	.quad	0
> -
> -ALIGN
> -# saved registers
> -saved_gdt:	.quad	0,0
> -saved_idt:	.quad	0,0
> -saved_ldt:	.quad	0
> -saved_tss:	.quad	0
> -
> -saved_cr0:	.quad 0
> -saved_cr3:	.quad 0
> -saved_cr4:	.quad 0
> -saved_efer:	.quad 0
> -saved_efer2:	.quad 0
> _

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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