diff mbox series

[RFC,V3,1/9] x86/pkeys: Create pkeys_common.h

Message ID 20201009194258.3207172-2-ira.weiny@intel.com (mailing list archive)
State New, archived
Headers show
Series PKS: Add Protection Keys Supervisor (PKS) support RFC v3 | expand

Commit Message

Ira Weiny Oct. 9, 2020, 7:42 p.m. UTC 
From: Ira Weiny <ira.weiny@intel.com>

Protection Keys User (PKU) and Protection Keys Supervisor (PKS) work in
similar fashions and can share common defines.  Normally, these defines
would be put in asm/pkeys.h to be used internally and externally to the
arch code.  However, the defines are required in pgtable.h and inclusion
of pkeys.h in that header creates complex dependencies which are best
resolved in a separate header.

Share these defines by moving those them into a new header, change their
names to reflect the common use, and include the header where needed.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
NOTE: The initialization of init_pkru_value cause checkpatch errors
because of the space after the '(' in the macros.  We leave this as is
because it is more readable in this format.  And it was existing code.
---
 arch/x86/include/asm/pgtable.h      | 13 ++++++-------
 arch/x86/include/asm/pkeys.h        |  2 ++
 arch/x86/include/asm/pkeys_common.h | 11 +++++++++++
 arch/x86/kernel/fpu/xstate.c        |  8 ++++----
 arch/x86/mm/pkeys.c                 | 14 ++++++--------
 5 files changed, 29 insertions(+), 19 deletions(-)
 create mode 100644 arch/x86/include/asm/pkeys_common.h

Comments

Dave Hansen Oct. 13, 2020, 5:46 p.m. UTC | #1 
On 10/9/20 12:42 PM, ira.weiny@intel.com wrote:
> Protection Keys User (PKU) and Protection Keys Supervisor (PKS) work
> in similar fashions and can share common defines.

Could we be a bit less abstract?  PKS and PKU each have:
1. A single control register
2. The same number of keys
3. The same number of bits in the register per key
4. Access and Write disable in the same bit locations

That means that we can share all the macros that synthesize and
manipulate register values between the two features.

> +++ b/arch/x86/include/asm/pkeys_common.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _ASM_X86_PKEYS_INTERNAL_H
> +#define _ASM_X86_PKEYS_INTERNAL_H
> +
> +#define PKR_AD_BIT 0x1
> +#define PKR_WD_BIT 0x2
> +#define PKR_BITS_PER_PKEY 2
> +
> +#define PKR_AD_KEY(pkey)	(PKR_AD_BIT << ((pkey) * PKR_BITS_PER_PKEY))

Now that this has moved away from its use-site, it's a bit less
self-documenting.  Let's add a comment:

/*
 * Generate an Access-Disable mask for the given pkey.  Several of these
 * can be OR'd together to generate pkey register values.
 */

Once that's in place, along with the updated changelog:

Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Ira Weiny Oct. 13, 2020, 7:44 p.m. UTC | #2 
On Tue, Oct 13, 2020 at 10:46:16AM -0700, Dave Hansen wrote:
> On 10/9/20 12:42 PM, ira.weiny@intel.com wrote:
> > Protection Keys User (PKU) and Protection Keys Supervisor (PKS) work
> > in similar fashions and can share common defines.
> 
> Could we be a bit less abstract?  PKS and PKU each have:
> 1. A single control register
> 2. The same number of keys
> 3. The same number of bits in the register per key
> 4. Access and Write disable in the same bit locations
> 
> That means that we can share all the macros that synthesize and
> manipulate register values between the two features.

Sure.  Done.

> 
> > +++ b/arch/x86/include/asm/pkeys_common.h
> > @@ -0,0 +1,11 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _ASM_X86_PKEYS_INTERNAL_H
> > +#define _ASM_X86_PKEYS_INTERNAL_H
> > +
> > +#define PKR_AD_BIT 0x1
> > +#define PKR_WD_BIT 0x2
> > +#define PKR_BITS_PER_PKEY 2
> > +
> > +#define PKR_AD_KEY(pkey)	(PKR_AD_BIT << ((pkey) * PKR_BITS_PER_PKEY))
> 
> Now that this has moved away from its use-site, it's a bit less
> self-documenting.  Let's add a comment:
> 
> /*
>  * Generate an Access-Disable mask for the given pkey.  Several of these
>  * can be OR'd together to generate pkey register values.
>  */

Fair enough. done.

> 
> Once that's in place, along with the updated changelog:
> 
> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>

Thanks,
Ira
diff mbox series

Patch

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index b836138ce852..2576154be6cf 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1361,9 +1361,7 @@  static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd)
 }
 #endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */
 
-#define PKRU_AD_BIT 0x1
-#define PKRU_WD_BIT 0x2
-#define PKRU_BITS_PER_PKEY 2
+#include <asm/pkeys_common.h>
 
 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
 extern u32 init_pkru_value;
@@ -1373,18 +1371,19 @@  extern u32 init_pkru_value;
 
 static inline bool __pkru_allows_read(u32 pkru, u16 pkey)
 {
-	int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;
-	return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits));
+	int pkru_pkey_bits = pkey * PKR_BITS_PER_PKEY;
+
+	return !(pkru & (PKR_AD_BIT << pkru_pkey_bits));
 }
 
 static inline bool __pkru_allows_write(u32 pkru, u16 pkey)
 {
-	int pkru_pkey_bits = pkey * PKRU_BITS_PER_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 & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits));
+	return !(pkru & ((PKR_AD_BIT|PKR_WD_BIT) << pkru_pkey_bits));
 }
 
 static inline u16 pte_flags_pkey(unsigned long pte_flags)
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index 2ff9b98812b7..f9feba80894b 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -2,6 +2,8 @@ 
 #ifndef _ASM_X86_PKEYS_H
 #define _ASM_X86_PKEYS_H
 
+#include <asm/pkeys_common.h>
+
 #define ARCH_DEFAULT_PKEY	0
 
 /*
diff --git a/arch/x86/include/asm/pkeys_common.h b/arch/x86/include/asm/pkeys_common.h
new file mode 100644
index 000000000000..a9f086f1e4b4
--- /dev/null
+++ b/arch/x86/include/asm/pkeys_common.h
@@ -0,0 +1,11 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_PKEYS_INTERNAL_H
+#define _ASM_X86_PKEYS_INTERNAL_H
+
+#define PKR_AD_BIT 0x1
+#define PKR_WD_BIT 0x2
+#define PKR_BITS_PER_PKEY 2
+
+#define PKR_AD_KEY(pkey)	(PKR_AD_BIT << ((pkey) * PKR_BITS_PER_PKEY))
+
+#endif /*_ASM_X86_PKEYS_INTERNAL_H */
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 038e19c0019e..b55cf3acd82a 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -991,7 +991,7 @@  int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 		unsigned long init_val)
 {
 	u32 old_pkru;
-	int pkey_shift = (pkey * PKRU_BITS_PER_PKEY);
+	int pkey_shift = (pkey * PKR_BITS_PER_PKEY);
 	u32 new_pkru_bits = 0;
 
 	/*
@@ -1010,16 +1010,16 @@  int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 
 	/* Set the bits we need in PKRU:  */
 	if (init_val & PKEY_DISABLE_ACCESS)
-		new_pkru_bits |= PKRU_AD_BIT;
+		new_pkru_bits |= PKR_AD_BIT;
 	if (init_val & PKEY_DISABLE_WRITE)
-		new_pkru_bits |= PKRU_WD_BIT;
+		new_pkru_bits |= PKR_WD_BIT;
 
 	/* Shift the bits in to the correct place in PKRU for pkey: */
 	new_pkru_bits <<= pkey_shift;
 
 	/* Get old PKRU and mask off any old bits in place: */
 	old_pkru = read_pkru();
-	old_pkru &= ~((PKRU_AD_BIT|PKRU_WD_BIT) << pkey_shift);
+	old_pkru &= ~((PKR_AD_BIT|PKR_WD_BIT) << pkey_shift);
 
 	/* Write old part along with new part: */
 	write_pkru(old_pkru | new_pkru_bits);
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 8873ed1438a9..f5efb4007e74 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -111,19 +111,17 @@  int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey
 	return vma_pkey(vma);
 }
 
-#define PKRU_AD_KEY(pkey)	(PKRU_AD_BIT << ((pkey) * PKRU_BITS_PER_PKEY))
-
 /*
  * Make the default PKRU value (at execve() time) as restrictive
  * as possible.  This ensures that any threads clone()'d early
  * in the process's lifetime will not accidentally get access
  * to data which is pkey-protected later on.
  */
-u32 init_pkru_value = PKRU_AD_KEY( 1) | PKRU_AD_KEY( 2) | PKRU_AD_KEY( 3) |
-		      PKRU_AD_KEY( 4) | PKRU_AD_KEY( 5) | PKRU_AD_KEY( 6) |
-		      PKRU_AD_KEY( 7) | PKRU_AD_KEY( 8) | PKRU_AD_KEY( 9) |
-		      PKRU_AD_KEY(10) | PKRU_AD_KEY(11) | PKRU_AD_KEY(12) |
-		      PKRU_AD_KEY(13) | PKRU_AD_KEY(14) | PKRU_AD_KEY(15);
+u32 init_pkru_value = PKR_AD_KEY( 1) | PKR_AD_KEY( 2) | PKR_AD_KEY( 3) |
+		      PKR_AD_KEY( 4) | PKR_AD_KEY( 5) | PKR_AD_KEY( 6) |
+		      PKR_AD_KEY( 7) | PKR_AD_KEY( 8) | PKR_AD_KEY( 9) |
+		      PKR_AD_KEY(10) | PKR_AD_KEY(11) | PKR_AD_KEY(12) |
+		      PKR_AD_KEY(13) | PKR_AD_KEY(14) | PKR_AD_KEY(15);
 
 /*
  * Called from the FPU code when creating a fresh set of FPU
@@ -173,7 +171,7 @@  static ssize_t init_pkru_write_file(struct file *file,
 	 * up immediately if someone attempts to disable access
 	 * or writes to pkey 0.
 	 */
-	if (new_init_pkru & (PKRU_AD_BIT|PKRU_WD_BIT))
+	if (new_init_pkru & (PKR_AD_BIT|PKR_WD_BIT))
 		return -EINVAL;
 
 	WRITE_ONCE(init_pkru_value, new_init_pkru);