linux-kernel - [tip: objtool/core] x86,bugs: Unconditionally allow spectre

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Date:   Fri, 29 Oct 2021 08:02:56 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Alexei Starovoitov <ast@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: objtool/core] x86,bugs: Unconditionally allow spectre_v2=retpoline,amd

The following commit has been merged into the objtool/core branch of tip:

Commit-ID:     f8a66d608a3e471e1202778c2a36cbdc96bae73b
Gitweb:        https://git.kernel.org/tip/f8a66d608a3e471e1202778c2a36cbdc96bae73b
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Tue, 26 Oct 2021 14:01:46 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Thu, 28 Oct 2021 23:25:29 +02:00

x86,bugs: Unconditionally allow spectre_v2=retpoline,amd

Currently Linux prevents usage of retpoline,amd on !AMD hardware, this
is unfriendly and gets in the way of testing. Remove this restriction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Reviewed-by: Borislav Petkov <bp@...e.de>
Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>
Tested-by: Alexei Starovoitov <ast@...nel.org>
Link: https://lore.kernel.org/r/20211026120310.487348118@infradead.org
---
 arch/x86/kernel/cpu/bugs.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index ecfca3b..ba43597 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -882,13 +882,6 @@ static enum spectre_v2_mitigation_cmd __init spectre_v2_parse_cmdline(void)
 		return SPECTRE_V2_CMD_AUTO;
 	}
 
-	if (cmd == SPECTRE_V2_CMD_RETPOLINE_AMD &&
-	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON &&
-	    boot_cpu_data.x86_vendor != X86_VENDOR_AMD) {
-		pr_err("retpoline,amd selected but CPU is not AMD. Switching to AUTO select\n");
-		return SPECTRE_V2_CMD_AUTO;
-	}
-
 	spec_v2_print_cond(mitigation_options[i].option,
 			   mitigation_options[i].secure);
 	return cmd;