Linux-kselftest Archive on lore.kernel.org
 help / color / Atom feed
From: ira.weiny@intel.com
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-mm@kvack.org,
	linux-kselftest@vger.kernel.org
Subject: [PATCH 03/10] x86/pks: Enable Protection Keys Supervisor (PKS)
Date: Thu, 22 Oct 2020 15:26:54 -0700
Message-ID: <20201022222701.887660-4-ira.weiny@intel.com> (raw)
In-Reply-To: <20201022222701.887660-1-ira.weiny@intel.com>

From: Fenghua Yu <fenghua.yu@intel.com>

Protection Keys for Supervisor pages (PKS) enables fast, hardware thread
specific, manipulation of permission restrictions on supervisor page
mappings.  It uses the same mechanism of Protection Keys as those on
User mappings but applies that mechanism to supervisor mappings using a
supervisor specific MSR.

Kernel users can thus defines 'domains' of page mappings which have an
extra level of protection beyond those specified in the supervisor page
table entries.

Define ARCH_HAS_SUPERVISOR_PKEYS to distinguish this functionality from
the existing ARCH_HAS_PKEYS and then enable PKS when configured and
indicated by the CPU instance.  While not strictly necessary in this
patch, ARCH_HAS_SUPERVISOR_PKEYS separates this functionality through
the patch series so it is introduced here.

Co-developed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

---
Changes since RFC V3
	Per Dave Hansen
		Update comment
		Add X86_FEATURE_PKS to disabled-features.h
	Rebase based on latest TIP tree
---
 arch/x86/Kconfig                            |  1 +
 arch/x86/include/asm/cpufeatures.h          |  1 +
 arch/x86/include/asm/disabled-features.h    |  8 +++++++-
 arch/x86/include/uapi/asm/processor-flags.h |  2 ++
 arch/x86/kernel/cpu/common.c                | 13 +++++++++++++
 mm/Kconfig                                  |  2 ++
 6 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index f6946b81f74a..78c4c749c6a9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1876,6 +1876,7 @@ config X86_INTEL_MEMORY_PROTECTION_KEYS
 	depends on X86_64 && (CPU_SUP_INTEL || CPU_SUP_AMD)
 	select ARCH_USES_HIGH_VMA_FLAGS
 	select ARCH_HAS_PKEYS
+	select ARCH_HAS_SUPERVISOR_PKEYS
 	help
 	  Memory Protection Keys provides a mechanism for enforcing
 	  page-based protections, but without requiring modification of the
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index dad350d42ecf..4deb580324e8 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -356,6 +356,7 @@
 #define X86_FEATURE_MOVDIRI		(16*32+27) /* MOVDIRI instruction */
 #define X86_FEATURE_MOVDIR64B		(16*32+28) /* MOVDIR64B instruction */
 #define X86_FEATURE_ENQCMD		(16*32+29) /* ENQCMD and ENQCMDS instructions */
+#define X86_FEATURE_PKS			(16*32+31) /* Protection Keys for Supervisor pages */
 
 /* AMD-defined CPU features, CPUID level 0x80000007 (EBX), word 17 */
 #define X86_FEATURE_OVERFLOW_RECOV	(17*32+ 0) /* MCA overflow recovery support */
diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
index 5861d34f9771..82540f0c5b6c 100644
--- a/arch/x86/include/asm/disabled-features.h
+++ b/arch/x86/include/asm/disabled-features.h
@@ -44,6 +44,12 @@
 # define DISABLE_OSPKE		(1<<(X86_FEATURE_OSPKE & 31))
 #endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */
 
+#ifdef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS
+# define DISABLE_PKS		0
+#else
+# define DISABLE_PKS		(1<<(X86_FEATURE_PKS & 31))
+#endif
+
 #ifdef CONFIG_X86_5LEVEL
 # define DISABLE_LA57	0
 #else
@@ -82,7 +88,7 @@
 #define DISABLED_MASK14	0
 #define DISABLED_MASK15	0
 #define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \
-			 DISABLE_ENQCMD)
+			 DISABLE_ENQCMD|DISABLE_PKS)
 #define DISABLED_MASK17	0
 #define DISABLED_MASK18	0
 #define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 19)
diff --git a/arch/x86/include/uapi/asm/processor-flags.h b/arch/x86/include/uapi/asm/processor-flags.h
index bcba3c643e63..191c574b2390 100644
--- a/arch/x86/include/uapi/asm/processor-flags.h
+++ b/arch/x86/include/uapi/asm/processor-flags.h
@@ -130,6 +130,8 @@
 #define X86_CR4_SMAP		_BITUL(X86_CR4_SMAP_BIT)
 #define X86_CR4_PKE_BIT		22 /* enable Protection Keys support */
 #define X86_CR4_PKE		_BITUL(X86_CR4_PKE_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 35ad8480c464..6a9ca938d9a9 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1494,6 +1494,18 @@ static void validate_apic_and_package_id(struct cpuinfo_x86 *c)
 #endif
 }
 
+/*
+ * PKS is independent of PKU and either or both may be supported on a CPU.
+ * Configure PKS if the CPU supports the feature.
+ */
+static void setup_pks(void)
+{
+	if (!cpu_feature_enabled(X86_FEATURE_PKS))
+		return;
+
+	cr4_set_bits(X86_CR4_PKS);
+}
+
 /*
  * This does the hard work of actually picking apart the CPU stuff...
  */
@@ -1591,6 +1603,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
 
 	x86_init_rdrand(c);
 	setup_pku(c);
+	setup_pks();
 
 	/*
 	 * Clear/Set all flags overridden by options, need do it
diff --git a/mm/Kconfig b/mm/Kconfig
index d42423f884a7..fc9ce7f65683 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -826,6 +826,8 @@ config ARCH_USES_HIGH_VMA_FLAGS
 	bool
 config ARCH_HAS_PKEYS
 	bool
+config ARCH_HAS_SUPERVISOR_PKEYS
+	bool
 
 config PERCPU_STATS
 	bool "Collect percpu memory statistics"
-- 
2.28.0.rc0.12.gb6a658bd00c9


  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-22 22:26 [PATCH 00/10] PKS: Add Protection Keys Supervisor (PKS) support ira.weiny
2020-10-22 22:26 ` [PATCH 01/10] x86/pkeys: Create pkeys_common.h ira.weiny
2020-10-22 22:26 ` [PATCH 02/10] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-10-22 22:26 ` ira.weiny [this message]
2020-10-22 22:26 ` [PATCH 04/10] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-10-22 22:26 ` [PATCH 05/10] x86/pks: Add PKS kernel API ira.weiny
2020-10-22 22:26 ` [PATCH 06/10] x86/entry: Move nmi entry/exit into common code ira.weiny
2020-10-23 21:50   ` Thomas Gleixner
2020-10-27  7:07     ` Ira Weiny
2020-10-27 14:18       ` Thomas Gleixner
2020-10-22 22:26 ` [PATCH 07/10] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-10-23 21:56   ` Thomas Gleixner
2020-10-27  7:11     ` Ira Weiny
2020-10-22 22:26 ` [PATCH 08/10] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-10-22 22:27 ` [PATCH 09/10] x86/fault: Report the PKRS state on fault ira.weiny
2020-10-22 22:27 ` [PATCH 10/10] x86/pks: Add PKS test code ira.weiny

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201022222701.887660-4-ira.weiny@intel.com \
    --to=ira.weiny@intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=bp@alien8.de \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=fenghua.yu@intel.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-kselftest Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-kselftest/0 linux-kselftest/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-kselftest linux-kselftest/ https://lore.kernel.org/linux-kselftest \
		linux-kselftest@vger.kernel.org
	public-inbox-index linux-kselftest

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kselftest


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git