From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
The syscall-level code is passed a protection key and need to
return an appropriate error code if the protection key is bogus.
We will be using this in subsequent patches.
Note that this also begins a series of arch-specific calls that
we need to expose in otherwise arch-independent code. We create
a linux/pkeys.h header where we will put *all* the stubs for
these functions.
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
b/arch/x86/Kconfig | 1 +
b/arch/x86/include/asm/pkeys.h | 6 ++++++
b/include/linux/pkeys.h | 25 +++++++++++++++++++++++++
b/mm/Kconfig | 2 ++
4 files changed, 34 insertions(+)
diff -puN /dev/null arch/x86/include/asm/pkeys.h
--- /dev/null 2015-12-10 15:28:13.322405854 -0800
+++ b/arch/x86/include/asm/pkeys.h 2016-02-12 10:44:26.560718780 -0800
@@ -0,0 +1,6 @@
+#ifndef _ASM_X86_PKEYS_H
+#define _ASM_X86_PKEYS_H
+
+#define arch_max_pkey() (boot_cpu_has(X86_FEATURE_OSPKE) ? 16 : 1)
+
+#endif /*_ASM_X86_PKEYS_H */
diff -puN arch/x86/Kconfig~pkeys-71-arch_validate_pkey arch/x86/Kconfig
--- a/arch/x86/Kconfig~pkeys-71-arch_validate_pkey 2016-02-12 10:44:26.555718551 -0800
+++ b/arch/x86/Kconfig 2016-02-12 10:44:26.561718825 -0800
@@ -156,6 +156,7 @@ config X86
select X86_DEV_DMA_OPS if X86_64
select X86_FEATURE_NAMES if PROC_FS
select ARCH_USES_HIGH_VMA_FLAGS if X86_INTEL_MEMORY_PROTECTION_KEYS
+ select ARCH_HAS_PKEYS if X86_INTEL_MEMORY_PROTECTION_KEYS
config INSTRUCTION_DECODER
def_bool y
diff -puN /dev/null include/linux/pkeys.h
--- /dev/null 2015-12-10 15:28:13.322405854 -0800
+++ b/include/linux/pkeys.h 2016-02-12 10:44:26.561718825 -0800
@@ -0,0 +1,25 @@
+#ifndef _LINUX_PKEYS_H
+#define _LINUX_PKEYS_H
+
+#include <linux/mm_types.h>
+#include <asm/mmu_context.h>
+
+#ifdef CONFIG_ARCH_HAS_PKEYS
+#include <asm/pkeys.h>
+#else /* ! CONFIG_ARCH_HAS_PKEYS */
+#define arch_max_pkey() (1)
+#endif /* ! CONFIG_ARCH_HAS_PKEYS */
+
+/*
+ * This is called from mprotect_pkey().
+ *
+ * Returns true if the protection keys is valid.
+ */
+static inline bool validate_pkey(int pkey)
+{
+ if (pkey < 0)
+ return false;
+ return (pkey < arch_max_pkey());
+}
+
+#endif /* _LINUX_PKEYS_H */
diff -puN mm/Kconfig~pkeys-71-arch_validate_pkey mm/Kconfig
--- a/mm/Kconfig~pkeys-71-arch_validate_pkey 2016-02-12 10:44:26.557718643 -0800
+++ b/mm/Kconfig 2016-02-12 10:44:26.562718871 -0800
@@ -672,3 +672,5 @@ config FRAME_VECTOR
config ARCH_USES_HIGH_VMA_FLAGS
bool
+config ARCH_HAS_PKEYS
+ bool
_
--
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