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Subject[PATCH V5 03/10] x86/pks: Add additional PKEY helper macros
Date
From: Ira Weiny <ira.weiny@intel.com>

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

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

---
Changes from V3:
new patch suggested by Dan Williams to use macros better.
---
arch/x86/include/asm/pgtable.h | 7 ++-----
arch/x86/include/asm/pkeys_common.h | 11 ++++++++---
arch/x86/mm/pkeys.c | 8 +++-----
3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index bfbfb951fe65..b1529b44a996 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1370,19 +1370,16 @@ 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 we need to 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 u16 pte_flags_pkey(unsigned long pte_flags)
diff --git a/arch/x86/include/asm/pkeys_common.h b/arch/x86/include/asm/pkeys_common.h
index e40b0ced733f..0681522974ba 100644
--- a/arch/x86/include/asm/pkeys_common.h
+++ b/arch/x86/include/asm/pkeys_common.h
@@ -6,10 +6,15 @@
#define PKR_WD_BIT 0x2
#define PKR_BITS_PER_PKEY 2

+#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))
+
/*
- * Generate an Access-Disable mask for the given pkey. Several of these can be
- * OR'd together to generate pkey register values.
+ * Generate an Access-Disable and Write-Disable mask for the given pkey.
+ * Several of the AD's are OR'd together to generate a default pkey register
+ * value.
*/
-#define PKR_AD_KEY(pkey) (PKR_AD_BIT << ((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/mm/pkeys.c b/arch/x86/mm/pkeys.c
index d1dfe743e79f..fc8c7e2bb21b 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -218,16 +218,14 @@ __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
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