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Date: Tue, 19 Apr 2022 10:06:15 -0700
From: ira.weiny@...el.com
To: Dave Hansen <dave.hansen@...ux.intel.com>,
"H. Peter Anvin" <hpa@...or.com>,
Dan Williams <dan.j.williams@...el.com>
Cc: Ira Weiny <ira.weiny@...el.com>, Fenghua Yu <fenghua.yu@...el.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
"Shankar, Ravi V" <ravi.v.shankar@...el.com>,
linux-kernel@...r.kernel.org
Subject: [PATCH V10 10/44] x86/pkeys: Enable PKS on cpus which support it
From: Ira Weiny <ira.weiny@...el.com>
Protection Keys for Supervisor pages (PKS) enables fast, hardware thread
specific, manipulation of permission restrictions on supervisor page
mappings. It uses a supervisor specific MSR to assign permissions to
the pkeys.
When PKS is configured and the cpu supports PKS, initialize the MSR, and
enable the hardware.
Add asm/pks.h to store new internal functions and structures such as
pks_setup().
Co-developed-by: Fenghua Yu <fenghua.yu@...el.com>
Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
Signed-off-by: Ira Weiny <ira.weiny@...el.com>
---
Changes for V10
Update to latest master branch
Changes for V9
Reword commit message
Move this after the patch defining PKS_INIT_VALUE
Changes for V8
Move setup_pks() into this patch with a default of all access
for all pkeys.
From Thomas
s/setup_pks/pks_setup/
Update Change log to better reflect exactly what this patch does.
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/include/asm/pks.h | 15 +++++++++++++++
arch/x86/include/uapi/asm/processor-flags.h | 2 ++
arch/x86/kernel/cpu/common.c | 2 ++
arch/x86/mm/pkeys.c | 17 +++++++++++++++++
5 files changed, 37 insertions(+)
create mode 100644 arch/x86/include/asm/pks.h
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index ee15311b6be1..e8e33b5ed507 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -809,6 +809,7 @@
#define MSR_IA32_TSC_DEADLINE 0x000006E0
+#define MSR_IA32_PKRS 0x000006E1
#define MSR_TSX_FORCE_ABORT 0x0000010F
diff --git a/arch/x86/include/asm/pks.h b/arch/x86/include/asm/pks.h
new file mode 100644
index 000000000000..8180fc59790b
--- /dev/null
+++ b/arch/x86/include/asm/pks.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_PKS_H
+#define _ASM_X86_PKS_H
+
+#ifdef CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS
+
+void pks_setup(void);
+
+#else /* !CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS */
+
+static inline void pks_setup(void) { }
+
+#endif /* CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS */
+
+#endif /* _ASM_X86_PKS_H */
diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
index c47cc7f2feeb..21b7783885b3 100644
--- a/arch/x86/include/uapi/asm/processor-flags.h
+++ b/arch/x86/include/uapi/asm/processor-flags.h
@@ -132,6 +132,8 @@
#define X86_CR4_PKE _BITUL(X86_CR4_PKE_BIT)
#define X86_CR4_CET_BIT 23 /* enable Control-flow Enforcement Technology */
#define X86_CR4_CET _BITUL(X86_CR4_CET_BIT)
+#define X86_CR4_PKS_BIT 24 /* enable Protection Keys for Supervisor */
+#define X86_CR4_PKS _BITUL(X86_CR4_PKS_BIT)
/*
* x86-64 Task Priority Register, CR8
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index e342ae4db3c4..4c0623783bd8 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -60,6 +60,7 @@
#include <asm/uv/uv.h>
#include <asm/sigframe.h>
#include <asm/traps.h>
+#include <asm/pks.h>
#include "cpu.h"
@@ -1764,6 +1765,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
x86_init_rdrand(c);
setup_pku(c);
setup_cet(c);
+ pks_setup();
/*
* Clear/Set all flags overridden by options, need do it
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 7c90b2188c5f..f904376570f4 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -6,6 +6,7 @@
#include <linux/debugfs.h> /* debugfs_create_u32() */
#include <linux/mm_types.h> /* mm_struct, vma, etc... */
#include <linux/pkeys.h> /* PKEY_* */
+#include <linux/pks-keys.h>
#include <uapi/asm-generic/mman-common.h>
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
@@ -209,3 +210,19 @@ u32 pkey_update_pkval(u32 pkval, u8 pkey, u32 accessbits)
pkval &= ~(PKEY_ACCESS_MASK << shift);
return pkval | accessbits << shift;
}
+
+#ifdef CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS
+
+/*
+ * PKS is independent of PKU and either or both may be supported on a CPU.
+ */
+void pks_setup(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_PKS))
+ return;
+
+ wrmsrl(MSR_IA32_PKRS, PKS_INIT_VALUE);
+ cr4_set_bits(X86_CR4_PKS);
+}
+
+#endif /* CONFIG_ARCH_ENABLE_SUPERVISOR_PKEYS */
--
2.35.1
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