linux-kernel - [PATCH V4 06/10] x86/fault: Adjust WARN

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Message-Id: <20210322053020.2287058-7-ira.weiny@intel.com>
Date:   Sun, 21 Mar 2021 22:30:16 -0700
From:   ira.weiny@...el.com
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Ira Weiny <ira.weiny@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Fenghua Yu <fenghua.yu@...el.com>,
        linux-doc@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: [PATCH V4 06/10] x86/fault: Adjust WARN_ON for PKey fault

From: Ira Weiny <ira.weiny@...el.com>

PKey faults may now happen on kernel mappings if the feature is enabled.
Remove the warning in the fault path if PKS is enabled.

Reviewed-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
 arch/x86/mm/fault.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a73347e2cdfc..731ec90ed413 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1141,11 +1141,12 @@ do_kern_addr_fault(struct pt_regs *regs, unsigned long hw_error_code,
 		   unsigned long address)
 {
 	/*
-	 * Protection keys exceptions only happen on user pages.  We
-	 * have no user pages in the kernel portion of the address
-	 * space, so do not expect them here.
+	 * PF_PK is expected on kernel addresses when supervisor pkeys are
+	 * enabled.
 	 */
-	WARN_ON_ONCE(hw_error_code & X86_PF_PK);
+	if (!cpu_feature_enabled(X86_FEATURE_PKS))
+		WARN_ON_ONCE(hw_error_code & X86_PF_PK);
+
 
 #ifdef CONFIG_X86_32
 	/*
-- 
2.28.0.rc0.12.gb6a658bd00c9