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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/x86/include/asm/pkru.h
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/include/asm/pkru.h')
-rw-r--r--arch/x86/include/asm/pkru.h62
1 files changed, 62 insertions, 0 deletions
diff --git a/arch/x86/include/asm/pkru.h b/arch/x86/include/asm/pkru.h
new file mode 100644
index 000000000..74f0a2d34
--- /dev/null
+++ b/arch/x86/include/asm/pkru.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_PKRU_H
+#define _ASM_X86_PKRU_H
+
+#include <asm/cpufeature.h>
+
+#define PKRU_AD_BIT 0x1u
+#define PKRU_WD_BIT 0x2u
+#define PKRU_BITS_PER_PKEY 2
+
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+extern u32 init_pkru_value;
+#define pkru_get_init_value() READ_ONCE(init_pkru_value)
+#else
+#define init_pkru_value 0
+#define pkru_get_init_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 (cpu_feature_enabled(X86_FEATURE_OSPKE))
+ return rdpkru();
+ return 0;
+}
+
+static inline void write_pkru(u32 pkru)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
+ return;
+ /*
+ * WRPKRU is relatively expensive compared to RDPKRU.
+ * Avoid WRPKRU when it would not change the value.
+ */
+ if (pkru != rdpkru())
+ wrpkru(pkru);
+}
+
+static inline void pkru_write_default(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_OSPKE))
+ return;
+
+ wrpkru(pkru_get_init_value());
+}
+
+#endif