linux-kernel - [PATCH V8 04/44] x86/pkeys: Add additional PKEY helper macros

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Date:   Thu, 27 Jan 2022 09:54:25 -0800
From:   ira.weiny@...el.com
To:     Dave Hansen <dave.hansen@...ux.intel.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     Ira Weiny <ira.weiny@...el.com>, Fenghua Yu <fenghua.yu@...el.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH V8 04/44] x86/pkeys: Add additional PKEY helper macros

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

Avoid open coding shift and mask operations by defining and using helper
macros for PKey operations.

Suggested-by: Dan Williams <dan.j.williams@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>

---
Changes for V8
	Move ahead of other patches.
	Simplify to only the macros used in the series
---
 arch/x86/include/asm/pkeys_common.h | 5 ++++-
 arch/x86/include/asm/pkru.h         | 8 ++------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/pkeys_common.h b/arch/x86/include/asm/pkeys_common.h
index 08c736669244..d02ab5bc3fff 100644
--- a/arch/x86/include/asm/pkeys_common.h
+++ b/arch/x86/include/asm/pkeys_common.h
@@ -6,6 +6,9 @@
 #define PKR_WD_BIT 0x2u
 #define PKR_BITS_PER_PKEY 2
 
-#define PKR_AD_KEY(pkey)	(PKR_AD_BIT << ((pkey) * PKR_BITS_PER_PKEY))
+#define PKR_PKEY_SHIFT(pkey)	(pkey * PKR_BITS_PER_PKEY)
+
+#define PKR_AD_KEY(pkey)	(PKR_AD_BIT << PKR_PKEY_SHIFT(pkey))
+#define PKR_WD_KEY(pkey)	(PKR_WD_BIT << PKR_PKEY_SHIFT(pkey))
 
 #endif /*_ASM_X86_PKEYS_COMMON_H */
diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h
index 06980dd42946..81ddf88ac3c9 100644
--- a/arch/x86/include/asm/pkru.h
+++ b/arch/x86/include/asm/pkru.h
@@ -15,17 +15,13 @@ extern u32 init_pkru_value;
 
 static inline bool __pkru_allows_read(u32 pkru, u16 pkey)
 {
-	int pkru_pkey_bits = pkey * PKR_BITS_PER_PKEY;
-
-	return !(pkru & (PKR_AD_BIT << pkru_pkey_bits));
+	return !(pkru & PKR_AD_KEY(pkey));
 }
 
 static inline bool __pkru_allows_write(u32 pkru, u16 pkey)
 {
-	int pkru_pkey_bits = pkey * PKR_BITS_PER_PKEY;
-
 	/* Access-disable disables writes too so check both bits here. */
-	return !(pkru & ((PKR_AD_BIT|PKR_WD_BIT) << pkru_pkey_bits));
+	return !(pkru & (PKR_AD_KEY(pkey) | PKR_WD_KEY(pkey)));
 }
 
 static inline u32 read_pkru(void)
-- 
2.31.1