linux-kernel - Re: [PATCHv11 05/19] x86/relocate_kernel: Use named labels for less confusion

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Message-ID: <1e1d1aea-7346-4022-9f5f-402d171adfda@suse.com>
Date: Wed, 29 May 2024 13:47:50 +0300
From: Nikolay Borisov <nik.borisov@...e.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
 Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 x86@...nel.org
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
 Peter Zijlstra <peterz@...radead.org>,
 Adrian Hunter <adrian.hunter@...el.com>,
 Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
 Elena Reshetova <elena.reshetova@...el.com>,
 Jun Nakajima <jun.nakajima@...el.com>,
 Rick Edgecombe <rick.p.edgecombe@...el.com>,
 Tom Lendacky <thomas.lendacky@....com>, "Kalra, Ashish"
 <ashish.kalra@....com>, Sean Christopherson <seanjc@...gle.com>,
 "Huang, Kai" <kai.huang@...el.com>, Ard Biesheuvel <ardb@...nel.org>,
 Baoquan He <bhe@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
 "K. Y. Srinivasan" <kys@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, kexec@...ts.infradead.org,
 linux-hyperv@...r.kernel.org, linux-acpi@...r.kernel.org,
 linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv11 05/19] x86/relocate_kernel: Use named labels for less
 confusion

On 28.05.24 г. 12:55 ч., Kirill A. Shutemov wrote:
> From: Borislav Petkov <bp@...en8.de>
> 
> That identity_mapped() functions was loving that "1" label to the point
> of completely confusing its readers.
> 
> Use named labels in each place for clarity.
> 
> No functional changes.
> 
> Signed-off-by: Borislav Petkov (AMD) <bp@...en8.de>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
> ---
>   arch/x86/kernel/relocate_kernel_64.S | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kernel/relocate_kernel_64.S b/arch/x86/kernel/relocate_kernel_64.S
> index 56cab1bb25f5..085eef5c3904 100644
> --- a/arch/x86/kernel/relocate_kernel_64.S
> +++ b/arch/x86/kernel/relocate_kernel_64.S
> @@ -148,9 +148,10 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
>   	 */
>   	movl	$X86_CR4_PAE, %eax
>   	testq	$X86_CR4_LA57, %r13
> -	jz	1f
> +	jz	.Lno_la57
>   	orl	$X86_CR4_LA57, %eax
> -1:
> +.Lno_la57:
> +
>   	movq	%rax, %cr4
>   
>   	jmp 1f

That jmp 1f becomes redundant now as it simply jumps 1 line below.

> @@ -165,9 +166,9 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
>   	 * used by kexec. Flush the caches before copying the kernel.
>   	 */
>   	testq	%r12, %r12
> -	jz 1f
> +	jz .Lsme_off
>   	wbinvd
> -1:
> +.Lsme_off:
>   
>   	movq	%rcx, %r11
>   	call	swap_pages
> @@ -187,7 +188,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
>   	 */
>   
>   	testq	%r11, %r11
> -	jnz 1f
> +	jnz .Lrelocate
>   	xorl	%eax, %eax
>   	xorl	%ebx, %ebx
>   	xorl    %ecx, %ecx
> @@ -208,7 +209,7 @@ SYM_CODE_START_LOCAL_NOALIGN(identity_mapped)
>   	ret
>   	int3
>   
> -1:
> +.Lrelocate:
>   	popq	%rdx
>   	leaq	PAGE_SIZE(%r10), %rsp
>   	ANNOTATE_RETPOLINE_SAFE