From: Dave Hansen <dave@sr71.net> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, Dave Hansen <dave@sr71.net>, dave.hansen@linux.intel.com Subject: [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Date: Wed, 06 Jan 2016 16:01:38 -0800 [thread overview] Message-ID: <20160107000138.E8A63FF9@viggo.jf.intel.com> (raw) In-Reply-To: <20160107000104.1A105322@viggo.jf.intel.com> From: Dave Hansen <dave.hansen@linux.intel.com> This sets the bit in 'cr4' to actually enable the protection keys feature. We also include a boot-time disable for the feature "nopku". Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE cpuid bit to appear set. At this point in boot, identify_cpu() has already run the actual CPUID instructions and populated the "cpu features" structures. We need to go back and re-run identify_cpu() to make sure it gets updated values. We *could* simply re-populate the 11th word of the cpuid data, but this is probably quick enough. Also note that with the cpu_has() check and X86_FEATURE_PKU present in disabled-features.h, we do not need an #ifdef for setup_pku(). Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> --- b/Documentation/kernel-parameters.txt | 3 ++ b/arch/x86/kernel/cpu/common.c | 41 ++++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff -puN arch/x86/kernel/cpu/common.c~pkeys-50-should-be-last-patch arch/x86/kernel/cpu/common.c --- a/arch/x86/kernel/cpu/common.c~pkeys-50-should-be-last-patch 2016-01-06 15:50:13.522512707 -0800 +++ b/arch/x86/kernel/cpu/common.c 2016-01-06 15:50:13.528512977 -0800 @@ -289,6 +289,46 @@ static __always_inline void setup_smap(s } /* + * Protection Keys are not available in 32-bit mode. + */ +static bool pku_disabled; +static __always_inline void setup_pku(struct cpuinfo_x86 *c) +{ + if (!cpu_has(c, X86_FEATURE_PKU)) + return; + if (pku_disabled) + return; + + cr4_set_bits(X86_CR4_PKE); + /* + * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE + * cpuid bit to be set. We need to ensure that we + * update that bit in this CPU's "cpu_info". + */ + get_cpu_cap(c); +} +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +static __init int setup_disable_pku(char *arg) +{ + /* + * Do not clear the X86_FEATURE_PKU bit. All of the + * runtime checks are against OSPKE so clearing the + * bit does nothing. + * + * This way, we will see "pku" in cpuinfo, but not + * "ospke", which is exactly what we want. It shows + * that the CPU has PKU, but the OS has not enabled it. + * This happens to be exactly how a system would look + * if we disabled the config option. + */ + pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n"); + pku_disabled = true; + return 1; +} +__setup("nopku", setup_disable_pku); +#endif /* CONFIG_X86_64 */ + +/* * Some CPU features depend on higher CPUID levels, which may not always * be available due to CPUID level capping or broken virtualization * software. Add those features to this table to auto-disable them. @@ -948,6 +988,7 @@ static void identify_cpu(struct cpuinfo_ init_hypervisor(c); x86_init_rdrand(c); x86_init_cache_qos(c); + setup_pku(c); /* * Clear/Set all flags overriden by options, need do it diff -puN Documentation/kernel-parameters.txt~pkeys-50-should-be-last-patch Documentation/kernel-parameters.txt --- a/Documentation/kernel-parameters.txt~pkeys-50-should-be-last-patch 2016-01-06 15:50:13.524512797 -0800 +++ b/Documentation/kernel-parameters.txt 2016-01-06 15:50:13.529513023 -0800 @@ -958,6 +958,9 @@ bytes respectively. Such letter suffixes See Documentation/x86/intel_mpx.txt for more information about the feature. + nopku [X86] Disable Memory Protection Keys CPU feature found + in some Intel CPUs. + eagerfpu= [X86] on enable eager fpu restore off disable eager fpu restore _
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@sr71.net> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, x86@kernel.org, Dave Hansen <dave@sr71.net>, dave.hansen@linux.intel.com Subject: [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Date: Wed, 06 Jan 2016 16:01:38 -0800 [thread overview] Message-ID: <20160107000138.E8A63FF9@viggo.jf.intel.com> (raw) In-Reply-To: <20160107000104.1A105322@viggo.jf.intel.com> From: Dave Hansen <dave.hansen@linux.intel.com> This sets the bit in 'cr4' to actually enable the protection keys feature. We also include a boot-time disable for the feature "nopku". Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE cpuid bit to appear set. At this point in boot, identify_cpu() has already run the actual CPUID instructions and populated the "cpu features" structures. We need to go back and re-run identify_cpu() to make sure it gets updated values. We *could* simply re-populate the 11th word of the cpuid data, but this is probably quick enough. Also note that with the cpu_has() check and X86_FEATURE_PKU present in disabled-features.h, we do not need an #ifdef for setup_pku(). Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> --- b/Documentation/kernel-parameters.txt | 3 ++ b/arch/x86/kernel/cpu/common.c | 41 ++++++++++++++++++++++++++++++++++ 2 files changed, 44 insertions(+) diff -puN arch/x86/kernel/cpu/common.c~pkeys-50-should-be-last-patch arch/x86/kernel/cpu/common.c --- a/arch/x86/kernel/cpu/common.c~pkeys-50-should-be-last-patch 2016-01-06 15:50:13.522512707 -0800 +++ b/arch/x86/kernel/cpu/common.c 2016-01-06 15:50:13.528512977 -0800 @@ -289,6 +289,46 @@ static __always_inline void setup_smap(s } /* + * Protection Keys are not available in 32-bit mode. + */ +static bool pku_disabled; +static __always_inline void setup_pku(struct cpuinfo_x86 *c) +{ + if (!cpu_has(c, X86_FEATURE_PKU)) + return; + if (pku_disabled) + return; + + cr4_set_bits(X86_CR4_PKE); + /* + * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE + * cpuid bit to be set. We need to ensure that we + * update that bit in this CPU's "cpu_info". + */ + get_cpu_cap(c); +} +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +static __init int setup_disable_pku(char *arg) +{ + /* + * Do not clear the X86_FEATURE_PKU bit. All of the + * runtime checks are against OSPKE so clearing the + * bit does nothing. + * + * This way, we will see "pku" in cpuinfo, but not + * "ospke", which is exactly what we want. It shows + * that the CPU has PKU, but the OS has not enabled it. + * This happens to be exactly how a system would look + * if we disabled the config option. + */ + pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n"); + pku_disabled = true; + return 1; +} +__setup("nopku", setup_disable_pku); +#endif /* CONFIG_X86_64 */ + +/* * Some CPU features depend on higher CPUID levels, which may not always * be available due to CPUID level capping or broken virtualization * software. Add those features to this table to auto-disable them. @@ -948,6 +988,7 @@ static void identify_cpu(struct cpuinfo_ init_hypervisor(c); x86_init_rdrand(c); x86_init_cache_qos(c); + setup_pku(c); /* * Clear/Set all flags overriden by options, need do it diff -puN Documentation/kernel-parameters.txt~pkeys-50-should-be-last-patch Documentation/kernel-parameters.txt --- a/Documentation/kernel-parameters.txt~pkeys-50-should-be-last-patch 2016-01-06 15:50:13.524512797 -0800 +++ b/Documentation/kernel-parameters.txt 2016-01-06 15:50:13.529513023 -0800 @@ -958,6 +958,9 @@ bytes respectively. Such letter suffixes See Documentation/x86/intel_mpx.txt for more information about the feature. + nopku [X86] Disable Memory Protection Keys CPU feature found + in some Intel CPUs. + eagerfpu= [X86] on enable eager fpu restore off disable eager fpu restore _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-01-07 0:03 UTC|newest] Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-01-07 0:01 [PATCH 00/31] x86: Memory Protection Keys (v8) Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 01/31] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-13 19:00 ` Vlastimil Babka 2016-01-13 19:00 ` Vlastimil Babka 2016-01-13 19:16 ` Dave Hansen 2016-01-13 19:16 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 02/31] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 03/31] x86, pkeys: Add Kconfig option Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 04/31] x86, pkeys: cpuid bit definition Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 05/31] x86, pkeys: define new CR4 bit Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 06/31] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 07/31] x86, pkeys: PTE bits for storing protection key Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 08/31] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 09/31] x86, pkeys: store protection in high VMA flags Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 10/31] x86, pkeys: arch-specific protection bits Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-08 19:31 ` Thomas Gleixner 2016-01-07 0:01 ` [PATCH 11/31] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 12/31] signals, pkeys: notify userspace about protection key faults Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 13/31] x86, pkeys: fill in pkey field in siginfo Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 14/31] x86, pkeys: add functions to fetch PKRU Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-08 19:32 ` Thomas Gleixner 2016-01-07 0:01 ` [PATCH 15/31] mm: factor out VMA fault permission checking Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 16/31] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 17/31] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 18/31] mm: add gup flag to indicate "foreign" mm access Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 19/31] x86, pkeys: optimize fault handling in access_error() Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 20/31] x86, pkeys: differentiate instruction fetches Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 21/31] x86, pkeys: dump PKRU with other kernel registers Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 23/31] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` Dave Hansen [this message] 2016-01-07 0:01 ` [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen 2016-01-07 0:01 ` [PATCH 25/31] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 26/31] x86, pkeys: add arch_validate_pkey() Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-08 19:34 ` Thomas Gleixner 2016-01-07 0:01 ` [PATCH 27/31] x86: separate out LDT init from context init Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 28/31] x86, fpu: allow setting of XSAVE state Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 0:01 ` [PATCH 29/31] x86, pkeys: allow kernel to modify user pkey rights register Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-08 19:40 ` Thomas Gleixner 2016-01-07 0:01 ` [PATCH 30/31] x86, pkeys: create an x86 arch_calc_vm_prot_bits() for VMA flags Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-08 19:40 ` Thomas Gleixner 2016-01-07 0:01 ` [PATCH 31/31] x86, pkeys: execute-only support Dave Hansen 2016-01-07 0:01 ` Dave Hansen 2016-01-07 21:02 ` Kees Cook 2016-01-07 21:02 ` Kees Cook 2016-01-07 22:25 ` Dave Hansen 2016-01-07 22:25 ` Dave Hansen 2016-01-07 21:10 ` Andy Lutomirski 2016-01-07 21:10 ` Andy Lutomirski 2016-01-07 22:13 ` Dave Hansen 2016-01-07 22:13 ` Dave Hansen 2016-01-07 22:44 ` Andy Lutomirski 2016-01-07 22:44 ` Andy Lutomirski 2016-01-08 19:51 ` Thomas Gleixner 2016-01-08 19:51 ` Thomas Gleixner 2016-01-29 18:16 [PATCH 00/31] x86: Memory Protection Keys (v9) Dave Hansen 2016-01-29 18:17 ` [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen 2016-01-29 18:17 ` Dave Hansen
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=20160107000138.E8A63FF9@viggo.jf.intel.com \ --to=dave@sr71.net \ --cc=dave.hansen@linux.intel.com \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --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: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.