linux-kernel - [tip: x86/fpu] x86/pkru: Provide pkru_get_init

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Message-ID: <162448615063.395.10363501284970136257.tip-bot2@tip-bot2>
Date:   Wed, 23 Jun 2021 22:09:10 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>, Borislav Petkov <bp@...e.de>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/fpu] x86/pkru: Provide pkru_get_init_value()

The following commit has been merged into the x86/fpu branch of tip:

Commit-ID:     739e2eec0f4849eb411567407d61491f923db405
Gitweb:        https://git.kernel.org/tip/739e2eec0f4849eb411567407d61491f923db405
Author:        Thomas Gleixner <tglx@...utronix.de>
AuthorDate:    Wed, 23 Jun 2021 14:02:08 +02:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Wed, 23 Jun 2021 19:02:49 +02:00

x86/pkru: Provide pkru_get_init_value()

When CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS is disabled then the following
code fails to compile:

     if (cpu_feature_enabled(X86_FEATURE_OSPKE)) {
     	u32 pkru = READ_ONCE(init_pkru_value);
	..
     }

because init_pkru_value is defined as '0' which makes READ_ONCE() upset.

Provide an accessor macro to avoid #ifdeffery all over the place.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lkml.kernel.org/r/20210623121455.404880646@linutronix.de
---
 arch/x86/include/asm/pkru.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h
index ec8dd28..19d3d7b 100644
--- a/arch/x86/include/asm/pkru.h
+++ b/arch/x86/include/asm/pkru.h
@@ -10,8 +10,10 @@
 
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
 extern u32 init_pkru_value;
+#define pkru_get_init_value()	READ_ONCE(init_pkru_value)
 #else
 #define init_pkru_value	0
+#define pkru_get_init_value()	0
 #endif
 
 static inline bool __pkru_allows_read(u32 pkru, u16 pkey)