linux-kernel - [PATCH v2 08/14] x86/fault: Skip erratum #93 workaround on new CPUs

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Message-Id: <8969c688ee663e99901cf4b0383bc6662ce79707.1612924255.git.luto@kernel.org>
Date:   Tue,  9 Feb 2021 18:33:40 -0800
From:   Andy Lutomirski <luto@...nel.org>
To:     x86@...nel.org
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Yonghong Song <yhs@...com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Andy Lutomirski <luto@...nel.org>
Subject: [PATCH v2 08/14] x86/fault: Skip erratum #93 workaround on new CPUs

Erratum #93 applies to the first generation of AMD K8 CPUs.  Skip the
workaround on newer CPUs.

Signed-off-by: Andy Lutomirski <luto@...nel.org>
---
 arch/x86/mm/fault.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index cbb1a9754473..3fe2f4800b69 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -442,9 +442,8 @@ static void dump_pagetable(unsigned long address)
  */
 static int is_errata93(struct pt_regs *regs, unsigned long address)
 {
-#if defined(CONFIG_X86_64) && defined(CONFIG_CPU_SUP_AMD)
-	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD
-	    || boot_cpu_data.x86 != 0xf)
+#if defined(CONFIG_X86_64)
+	if (!is_amd_k8_pre_npt())
 		return 0;
 
 	if (user_mode(regs))
-- 
2.29.2