From: "tip-bot2 for Ira Weiny" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Ira Weiny <ira.weiny@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: x86/mm] Documentation/protection-keys: Clean up documentation for User Space pkeys
Date: Tue, 07 Jun 2022 23:09:53 -0000 [thread overview]
Message-ID: <165464339351.4207.13791430848488231130.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20220419170649.1022246-2-ira.weiny@intel.com>
The following commit has been merged into the x86/mm branch of tip:
Commit-ID: f8c1d4ca55177326adad1fdc6bf602423a507542
Gitweb: https://git.kernel.org/tip/f8c1d4ca55177326adad1fdc6bf602423a507542
Author: Ira Weiny <ira.weiny@intel.com>
AuthorDate: Tue, 19 Apr 2022 10:06:06 -07:00
Committer: Dave Hansen <dave.hansen@linux.intel.com>
CommitterDate: Tue, 07 Jun 2022 16:06:22 -07:00
Documentation/protection-keys: Clean up documentation for User Space pkeys
The documentation for user space pkeys was a bit dated including things
such as Amazon and distribution testing information which is irrelevant
now.
Update the documentation. This also streamlines adding the Supervisor
pkey documentation later on.
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20220419170649.1022246-2-ira.weiny@intel.com
---
Documentation/core-api/protection-keys.rst | 44 ++++++++++-----------
1 file changed, 21 insertions(+), 23 deletions(-)
diff --git a/Documentation/core-api/protection-keys.rst b/Documentation/core-api/protection-keys.rst
index ec575e7..bf28ac0 100644
--- a/Documentation/core-api/protection-keys.rst
+++ b/Documentation/core-api/protection-keys.rst
@@ -4,31 +4,29 @@
Memory Protection Keys
======================
-Memory Protection Keys for Userspace (PKU aka PKEYs) is a feature
-which is found on Intel's Skylake (and later) "Scalable Processor"
-Server CPUs. It will be available in future non-server Intel parts
-and future AMD processors.
-
-For anyone wishing to test or use this feature, it is available in
-Amazon's EC2 C5 instances and is known to work there using an Ubuntu
-17.04 image.
-
-Memory Protection Keys provides a mechanism for enforcing page-based
-protections, but without requiring modification of the page tables
-when an application changes protection domains. It works by
-dedicating 4 previously ignored bits in each page table entry to a
-"protection key", giving 16 possible keys.
-
-There is also a new user-accessible register (PKRU) with two separate
-bits (Access Disable and Write Disable) for each key. Being a CPU
-register, PKRU is inherently thread-local, potentially giving each
+Memory Protection Keys provide a mechanism for enforcing page-based
+protections, but without requiring modification of the page tables when an
+application changes protection domains.
+
+Pkeys Userspace (PKU) is a feature which can be found on:
+ * Intel server CPUs, Skylake and later
+ * Intel client CPUs, Tiger Lake (11th Gen Core) and later
+ * Future AMD CPUs
+
+Pkeys work by dedicating 4 previously Reserved bits in each page table entry to
+a "protection key", giving 16 possible keys.
+
+Protections for each key are defined with a per-CPU user-accessible register
+(PKRU). Each of these is a 32-bit register storing two bits (Access Disable
+and Write Disable) for each of 16 keys.
+
+Being a CPU register, PKRU is inherently thread-local, potentially giving each
thread a different set of protections from every other thread.
-There are two new instructions (RDPKRU/WRPKRU) for reading and writing
-to the new register. The feature is only available in 64-bit mode,
-even though there is theoretically space in the PAE PTEs. These
-permissions are enforced on data access only and have no effect on
-instruction fetches.
+There are two instructions (RDPKRU/WRPKRU) for reading and writing to the
+register. The feature is only available in 64-bit mode, even though there is
+theoretically space in the PAE PTEs. These permissions are enforced on data
+access only and have no effect on instruction fetches.
Syscalls
========
next prev parent reply other threads:[~2022-06-08 2:03 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 17:06 [PATCH V10 00/44] PKS/PMEM: Add Stray Write Protection ira.weiny
2022-04-19 17:06 ` [PATCH V10 01/44] Documentation/protection-keys: Clean up documentation for User Space pkeys ira.weiny
2022-06-07 23:09 ` tip-bot2 for Ira Weiny [this message]
2022-04-19 17:06 ` [PATCH V10 02/44] x86/pkeys: Clarify PKRU_AD_KEY macro ira.weiny
2022-06-07 23:09 ` [tip: x86/mm] " tip-bot2 for Ira Weiny
2022-04-19 17:06 ` [PATCH V10 03/44] x86/pkeys: Make PKRU macros generic ira.weiny
2022-04-19 17:06 ` [PATCH V10 04/44] x86/fpu: Refactor arch_set_user_pkey_access() ira.weiny
2022-04-19 17:06 ` [PATCH V10 05/44] mm/pkeys: Add Kconfig options for PKS ira.weiny
2022-04-19 17:06 ` [PATCH V10 06/44] x86/pkeys: Add PKS CPU feature bit ira.weiny
2022-04-19 17:06 ` [PATCH V10 07/44] x86/fault: Adjust WARN_ON for pkey fault ira.weiny
2022-04-19 17:06 ` [PATCH V10 08/44] Documentation/pkeys: Add initial PKS documentation ira.weiny
2022-05-09 22:03 ` Kees Cook
2022-05-10 17:18 ` Ira Weiny
2022-05-10 20:17 ` Kees Cook
2022-04-19 17:06 ` [PATCH V10 09/44] mm/pkeys: Provide for PKS key allocation ira.weiny
2022-04-19 17:06 ` [PATCH V10 10/44] x86/pkeys: Enable PKS on cpus which support it ira.weiny
2022-04-19 17:06 ` [PATCH V10 11/44] mm/pkeys: Define PKS page table macros ira.weiny
2022-04-19 17:06 ` [PATCH V10 12/44] x86/pkeys: Introduce pks_write_pkrs() ira.weiny
2022-04-19 17:06 ` [PATCH V10 13/44] x86/pkeys: Preserve the PKS MSR on context switch ira.weiny
2022-04-19 17:06 ` [PATCH V10 14/44] mm/pkeys: Introduce pks_set_readwrite() ira.weiny
2022-05-09 21:38 ` Kees Cook
2022-05-10 21:33 ` Ira Weiny
2022-05-10 22:08 ` Kees Cook
2022-05-10 22:26 ` Edgecombe, Rick P
2022-05-11 3:15 ` Kees Cook
2022-05-11 17:59 ` Ira Weiny
2022-04-19 17:06 ` [PATCH V10 15/44] mm/pkeys: Introduce pks_set_noaccess() ira.weiny
2022-04-19 17:06 ` [PATCH V10 16/44] mm/pkeys: Introduce PKS fault callbacks ira.weiny
2022-04-19 17:06 ` [PATCH V10 17/44] x86/entry: Add auxiliary pt_regs space ira.weiny
2022-04-19 17:06 ` [PATCH V10 18/44] entry: Pass pt_regs to irqentry_exit_cond_resched() ira.weiny
2022-04-19 17:06 ` [PATCH V10 19/44] entry: Add calls for save/restore auxiliary pt_regs ira.weiny
2022-04-19 17:06 ` [PATCH V10 20/44] x86/entry: Define arch_{save|restore}_auxiliary_pt_regs() ira.weiny
2022-04-19 17:06 ` [PATCH V10 21/44] x86/pkeys: Preserve PKRS MSR across exceptions ira.weiny
2022-04-19 17:06 ` [PATCH V10 22/44] x86/fault: Print PKS MSR on fault ira.weiny
2022-04-19 17:06 ` [PATCH V10 23/44] mm/pkeys: Introduce pks_update_exception() ira.weiny
2022-04-19 17:06 ` [PATCH V10 24/44] mm/pkeys: Add pks_available() ira.weiny
2022-04-19 17:06 ` [PATCH V10 25/44] memremap_pages: Add Kconfig for DEVMAP_ACCESS_PROTECTION ira.weiny
2022-04-19 17:06 ` [PATCH V10 26/44] memremap_pages: Introduce pgmap_protection_available() ira.weiny
2022-04-19 17:06 ` [PATCH V10 27/44] memremap_pages: Introduce a PGMAP_PROTECTION flag ira.weiny
2022-04-19 17:06 ` [PATCH V10 28/44] memremap_pages: Introduce devmap_protected() ira.weiny
2022-04-19 17:06 ` [PATCH V10 29/44] memremap_pages: Reserve a PKS pkey for eventual use by PMEM ira.weiny
2022-04-19 17:06 ` [PATCH V10 30/44] memremap_pages: Set PKS pkey in PTEs if requested ira.weiny
2022-04-19 17:06 ` [PATCH V10 31/44] memremap_pages: Define pgmap_set_{readwrite|noaccess}() calls ira.weiny
2022-04-19 17:06 ` [PATCH V10 32/44] memremap_pages: Add memremap.pks_fault_mode ira.weiny
2022-04-19 17:06 ` [PATCH V10 33/44] kmap: Make kmap work for devmap protected pages ira.weiny
2022-04-28 15:50 ` Christoph Hellwig
2022-05-12 1:25 ` Ira Weiny
2022-05-17 22:46 ` Ira Weiny
2022-05-18 7:33 ` Christoph Hellwig
2022-05-19 20:29 ` Ira Weiny
2022-04-19 17:06 ` [PATCH V10 34/44] dax: Stray access protection for dax_direct_access() ira.weiny
2022-04-19 17:06 ` [PATCH V10 35/44] nvdimm/pmem: Enable stray access protection ira.weiny
2022-04-19 17:06 ` [PATCH V10 36/44] devdax: " ira.weiny
2022-04-19 17:06 ` [PATCH V10 37/44] mm/pkeys: PKS testing, add initial test code ira.weiny
2022-04-19 17:06 ` [PATCH V10 38/44] x86/selftests: Add test_pks ira.weiny
2022-04-19 17:06 ` [PATCH V10 39/44] mm/pkeys: PKS testing, add a fault call back ira.weiny
2022-04-19 17:06 ` [PATCH V10 40/44] mm/pkeys: PKS testing, add pks_set_*() tests ira.weiny
2022-04-19 17:06 ` [PATCH V10 41/44] mm/pkeys: PKS testing, test context switching ira.weiny
2022-04-19 17:06 ` [PATCH V10 42/44] mm/pkeys: PKS testing, Add exception test ira.weiny
2022-04-19 17:06 ` [PATCH V10 43/44] mm/pkeys: PKS testing, test pks_update_exception() ira.weiny
2022-04-19 17:06 ` [PATCH V10 44/44] mm/pkeys: PKS testing, add test for all keys ira.weiny
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