x86/pkeys: Move read_pkru() and write_pkru()

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>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.102647114@linutronix.de

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 7de2384..5764cbe 100644 (file)
--- 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 */

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index b1099f2..ec0d8e1 100644 (file)
--- 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_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
-
-#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

diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h
new file mode 100644 (file)
index 0000000..35ffcfd
--- /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

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index d08307d..4651ab0 100644 (file)
--- 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>

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8d36f0c..62926f1 100644 (file)
--- 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"

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6f651b9..07f7888 100644 (file)
--- 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>

diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index a840ac7..a02cfcf 100644 (file)
--- 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)
 {