[patch V2 33/52] x86/pkeys: Move read_pkru() and write_pkru()

Thomas Gleixner
2021-06-14T16:39:46Z

From: Dave Hansen <dave.hansen@linux.intel.com>

write_pkru() was originally used just to write to the PKRU register. It
was mercifully short and sweet and was not out of place in pgtable.h with
some other pkey-related code.

But, later work included a requirement to also modify the task XSAVE
buffer when updating the register. This really is more related to the
XSAVE architecture than to paging.

Move the read/write_pkru() to asm/pkru.h. pgtable.h won't miss them.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/fpu/xstate.h | 1
arch/x86/include/asm/pgtable.h | 57 -----------------------------------
arch/x86/include/asm/pkru.h | 61 ++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/process_64.c | 1
arch/x86/kvm/svm/sev.c | 1
arch/x86/kvm/x86.c | 1
arch/x86/mm/pkeys.c | 1
7 files changed, 67 insertions(+), 56 deletions(-)

--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -6,6 +6,7 @@
#include <linux/types.h>

#include <asm/processor.h>
+#include <asm/fpu/api.h>
#include <asm/user.h>

/* Bit 63 of XCR0 is reserved for future expansion */
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -23,7 +23,7 @@

#ifndef __ASSEMBLY__
#include <asm/x86_init.h>
-#include <asm/fpu/xstate.h>
+#include <asm/pkru.h>
#include <asm/fpu/api.h>
#include <asm-generic/pgtable_uffd.h>

@@ -126,35 +126,6 @@ static inline int pte_dirty(pte_t pte)
return pte_flags(pte) & _PAGE_DIRTY;
}

-
-static inline u32 read_pkru(void)
-{
- if (boot_cpu_has(X86_FEATURE_OSPKE))
- return rdpkru();
- return 0;
-}
-
-static inline void write_pkru(u32 pkru)
-{
- struct pkru_state *pk;
-
- if (!boot_cpu_has(X86_FEATURE_OSPKE))
- return;
-
- pk = get_xsave_addr(&current->thread.fpu.state.xsave, XFEATURE_PKRU);
-
- /*
- * The PKRU value in xstate needs to be in sync with the value that is
- * written to the CPU. The FPU restore on return to userland would
- * otherwise load the previous value again.
- */
- fpregs_lock();
- if (pk)
- pk->pkru = pkru;
- __write_pkru(pkru);
- fpregs_unlock();
-}
-
static inline int pte_young(pte_t pte)
{
return pte_flags(pte) & _PAGE_ACCESSED;
@@ -1360,32 +1331,6 @@ static inline pmd_t pmd_swp_clear_uffd_w
}
#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */

-#define PKRU_AD_BIT 0x1
-#define PKRU_WD_BIT 0x2
-#define PKRU_BITS_PER_PKEY 2
-
-#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
-extern u32 init_pkru_value;
-#else
-#define init_pkru_value 0
-#endif
-
-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));
-}
-
-static inline bool __pkru_allows_write(u32 pkru, u16 pkey)
-{
- int pkru_pkey_bits = pkey * PKRU_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));
-}
-
static inline u16 pte_flags_pkey(unsigned long pte_flags)
{
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
--- /dev/null
+++ b/arch/x86/include/asm/pkru.h
@@ -0,0 +1,61 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_PKRU_H
+#define _ASM_X86_PKRU_H
+
+#include <asm/fpu/xstate.h>
+
+#define PKRU_AD_BIT 0x1
+#define PKRU_WD_BIT 0x2
+#define PKRU_BITS_PER_PKEY 2
+
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+extern u32 init_pkru_value;
+#else
+#define init_pkru_value 0
+#endif
+
+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));
+}
+
+static inline bool __pkru_allows_write(u32 pkru, u16 pkey)
+{
+ int pkru_pkey_bits = pkey * PKRU_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));
+}
+
+static inline u32 read_pkru(void)
+{
+ if (boot_cpu_has(X86_FEATURE_OSPKE))
+ return rdpkru();
+ return 0;
+}
+
+static inline void write_pkru(u32 pkru)
+{
+ struct pkru_state *pk;
+
+ if (!boot_cpu_has(X86_FEATURE_OSPKE))
+ return;
+
+ pk = get_xsave_addr(&current->thread.fpu.state.xsave, XFEATURE_PKRU);
+
+ /*
+ * The PKRU value in xstate needs to be in sync with the value that is
+ * written to the CPU. The FPU restore on return to userland would
+ * otherwise load the previous value again.
+ */
+ fpregs_lock();
+ if (pk)
+ pk->pkru = pkru;
+ __write_pkru(pkru);
+ fpregs_unlock();
+}
+
+#endif
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -41,6 +41,7 @@
#include <linux/syscalls.h>

#include <asm/processor.h>
+#include <asm/pkru.h>
#include <asm/fpu/internal.h>
#include <asm/mmu_context.h>
#include <asm/prctl.h>
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -19,6 +19,7 @@
#include <linux/trace_events.h>
#include <asm/fpu/internal.h>

+#include <asm/pkru.h>
#include <asm/trapnr.h>

#include "x86.h"
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -65,6 +65,7 @@
#include <asm/msr.h>
#include <asm/desc.h>
#include <asm/mce.h>
+#include <asm/pkru.h>
#include <linux/kernel_stat.h>
#include <asm/fpu/internal.h> /* Ugh! */
#include <asm/pvclock.h>
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -10,6 +10,7 @@

#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/mmu_context.h> /* vma_pkey() */
+#include <asm/pkru.h> /* read/write_pkru() */

int __execute_only_pkey(struct mm_struct *mm)
{