linux-kernel - [PATCH V7 03/18] x86/pks: Add additional PKEY helper macros

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Message-Id: <20210804043231.2655537-4-ira.weiny@intel.com>
Date:   Tue,  3 Aug 2021 21:32:16 -0700
From:   ira.weiny@...el.com
To:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     Ira Weiny <ira.weiny@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, nvdimm@...ts.linux.dev,
        linux-mm@...ck.org
Subject: [PATCH V7 03/18] x86/pks: 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.

Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
 arch/x86/include/asm/pkeys_common.h | 6 +++++-
 arch/x86/include/asm/pkru.h         | 6 ++----
 arch/x86/mm/pkeys.c                 | 8 +++-----
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/pkeys_common.h b/arch/x86/include/asm/pkeys_common.h
index f3277717faeb..8a3c6d2e6a8a 100644
--- a/arch/x86/include/asm/pkeys_common.h
+++ b/arch/x86/include/asm/pkeys_common.h
@@ -6,6 +6,10 @@
 #define PKR_WD_BIT 0x2
 #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_PKEY_MASK(pkey)  (((1 << PKR_BITS_PER_PKEY) - 1) << PKR_PKEY_SHIFT(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 a74325b0d1df..fb44ff542028 100644
--- a/arch/x86/include/asm/pkru.h
+++ b/arch/x86/include/asm/pkru.h
@@ -15,15 +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)
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index ca2e20b18645..75437aa8fc56 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -200,16 +200,14 @@ __setup("init_pkru=", setup_init_pkru);
  */
 u32 update_pkey_val(u32 pk_reg, int pkey, unsigned int flags)
 {
-	int pkey_shift = pkey * PKR_BITS_PER_PKEY;
-
 	/*  Mask out old bit values */
-	pk_reg &= ~(((1 << PKR_BITS_PER_PKEY) - 1) << pkey_shift);
+	pk_reg &= ~PKR_PKEY_MASK(pkey);
 
 	/*  Or in new values */
 	if (flags & PKEY_DISABLE_ACCESS)
-		pk_reg |= PKR_AD_BIT << pkey_shift;
+		pk_reg |= PKR_AD_KEY(pkey);
 	if (flags & PKEY_DISABLE_WRITE)
-		pk_reg |= PKR_WD_BIT << pkey_shift;
+		pk_reg |= PKR_WD_KEY(pkey);
 
 	return pk_reg;
 }
-- 
2.28.0.rc0.12.gb6a658bd00c9