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From: Nikolay Borisov <nik.borisov@suse.com>
To: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>, x86@kernel.org
Cc: David Kaplan <david.kaplan@amd.com>,
	linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Josh Poimboeuf <jpoimboe@kernel.org>
Subject: Re: [PATCH v3 3/7] x86/bugs: Exit early if return thunk is already set
Date: Fri, 23 May 2025 13:28:58 +0300	[thread overview]
Message-ID: <6b4a225e-c7ff-45e9-a2bb-62454927de57@suse.com> (raw)
In-Reply-To: <20250522-eibrs-fix-v3-3-12704e291e1e@linux.intel.com>



On 5/23/25 04:21, Pawan Gupta wrote:
> When the exact same return thunk is already set, avoid the warning and exit
> early. This is to prepare for ITS to also set CDT return thunk independent
> of retbleed.

Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>

> 
> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
> ---
>   arch/x86/kernel/cpu/bugs.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index 94d0de3e61aec32b3b67c8d21f89a8c67b93dff3..354593065025fd7c5727e955d76523777b3da9ee 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -113,6 +113,9 @@ void (*x86_return_thunk)(void) __ro_after_init = __x86_return_thunk;
>   
>   static void __init set_return_thunk(void *thunk)
>   {
> +	if (thunk == x86_return_thunk)
> +		return;
> +
>   	if (x86_return_thunk != __x86_return_thunk)
>   		pr_warn("x86/bugs: return thunk changed\n");
>   
> 


  reply	other threads:[~2025-05-23 10:29 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-23  1:20 [PATCH v3 0/7] eIBRS fixes Pawan Gupta
2025-05-23  1:20 ` [PATCH v3 1/7] x86/retbleed: Avoid AUTO after the select step Pawan Gupta
2025-05-24  9:29   ` Borislav Petkov
2025-05-23  1:20 ` [PATCH v3 2/7] x86/retbleed: Simplify the =stuff checks Pawan Gupta
2025-05-24 11:16   ` Borislav Petkov
2025-05-23  1:21 ` [PATCH v3 3/7] x86/bugs: Exit early if return thunk is already set Pawan Gupta
2025-05-23 10:28   ` Nikolay Borisov [this message]
2025-05-24 11:27   ` Borislav Petkov
2025-05-28 21:55     ` Pawan Gupta
2025-05-23  1:21 ` [PATCH v3 4/7] x86/its: Use switch/case to apply mitigation Pawan Gupta
2025-05-23  1:21 ` [PATCH v3 5/7] x86/retbleed: Introduce cdt_possible() Pawan Gupta
2025-05-23  1:21 ` [PATCH v3 6/7] x86/its: Remove =stuff dependency on retbleed Pawan Gupta
2025-05-23  1:22 ` [PATCH v3 7/7] x86/its: Allow stuffing in eIBRS+retpoline mode also Pawan Gupta

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