From: Borislav Petkov <bp@alien8.de>
To: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Andy Lutomirski <luto@amacapital.net>,
Balbir Singh <bsingharora@gmail.com>,
Cyrill Gorcunov <gorcunov@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Eugene Syromiatnikov <esyr@redhat.com>,
Florian Weimer <fweimer@redhat.com>,
"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Kees Cook <keescook@chromium.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Nadav Amit <nadav.amit@gmail.com>,
Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Randy Dunlap <rdunlap@infradead.org>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>
Subject: Re: [PATCH v5 02/27] x86/fpu/xstate: Change names to separate XSAVES system and user states
Date: Mon, 15 Oct 2018 19:03:20 +0200 [thread overview]
Message-ID: <20181015170320.GF11434@zn.tnic> (raw)
Message-ID: <20181015170320.bpvxeutlYM0E2IWGSYxK8VMuv1HAYfZDvTnrSdVl1H4@z> (raw)
In-Reply-To: <20181011151523.27101-3-yu-cheng.yu@intel.com>
On Thu, Oct 11, 2018 at 08:14:58AM -0700, Yu-cheng Yu wrote:
> Control Flow Enforcement (CET) MSRs are XSAVES system/supervisor
> states. To support CET, we introduce XSAVES system states first.
>
> XSAVES is a "supervisor" instruction and, comparing to XSAVE, saves
> additional "supervisor" states that can be modified only from CPL 0.
> However, these states are per-task and not kernel's own. Rename
> "supervisor" states to "system" states to clearly separate them from
> "user" states.
>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
> ---
> arch/x86/include/asm/fpu/internal.h | 4 +-
> arch/x86/include/asm/fpu/xstate.h | 20 +++----
> arch/x86/kernel/fpu/core.c | 4 +-
> arch/x86/kernel/fpu/init.c | 2 +-
> arch/x86/kernel/fpu/signal.c | 6 +--
> arch/x86/kernel/fpu/xstate.c | 82 ++++++++++++++---------------
> 6 files changed, 57 insertions(+), 61 deletions(-)
...
> diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
> index 87a57b7642d3..e7cbaed12ef1 100644
> --- a/arch/x86/kernel/fpu/xstate.c
> +++ b/arch/x86/kernel/fpu/xstate.c
> @@ -51,13 +51,14 @@ static short xsave_cpuid_features[] __initdata = {
> };
>
> /*
> - * Mask of xstate features supported by the CPU and the kernel:
> + * Mask of supported 'user' xstate features derived from boot_cpu_has() and
> + * SUPPORTED_XFEATURES_MASK.
<--- This comment here looks like a good place to put some blurb about
user and system states, what they are, what the distinction is and so
on.
> */
> -u64 xfeatures_mask __read_mostly;
> +u64 xfeatures_mask_user __read_mostly;
>
> static unsigned int xstate_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1};
> static unsigned int xstate_sizes[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] = -1};
> -static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
> +static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask_user)*8];
>
> /*
> * The XSAVE area of kernel can be in standard or compacted format;
> @@ -82,7 +83,7 @@ void fpu__xstate_clear_all_cpu_caps(void)
> */
> int cpu_has_xfeatures(u64 xfeatures_needed, const char **feature_name)
> {
> - u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask;
> + u64 xfeatures_missing = xfeatures_needed & ~xfeatures_mask_user;
>
> if (unlikely(feature_name)) {
> long xfeature_idx, max_idx;
> @@ -113,14 +114,11 @@ int cpu_has_xfeatures(u64 xfeatures_needed, const char **feature_name)
> }
> EXPORT_SYMBOL_GPL(cpu_has_xfeatures);
>
> -static int xfeature_is_supervisor(int xfeature_nr)
> +static int xfeature_is_system(int xfeature_nr)
> {
> /*
> - * We currently do not support supervisor states, but if
> - * we did, we could find out like this.
> - *
> * SDM says: If state component 'i' is a user state component,
> - * ECX[0] return 0; if state component i is a supervisor
> + * ECX[0] return 0; if state component i is a system
is 0
> * state component, ECX[0] returns 1.
is 1.
> */
> u32 eax, ebx, ecx, edx;
...
> @@ -242,7 +238,7 @@ void fpu__init_cpu_xstate(void)
> */
> static int xfeature_enabled(enum xfeature xfeature)
> {
> - return !!(xfeatures_mask & (1UL << xfeature));
> + return !!(xfeatures_mask_user & BIT_ULL(xfeature));
> }
>
> /*
> @@ -272,7 +268,7 @@ static void __init setup_xstate_features(void)
> cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
>
> /*
> - * If an xfeature is supervisor state, the offset
> + * If an xfeature is system state, the offset
is a system state, ...
> * in EBX is invalid. We leave it to -1.
> */
> if (xfeature_is_user(i))
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
next prev parent reply other threads:[~2018-10-16 0:49 UTC|newest]
Thread overview: 160+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 15:14 [PATCH v5 00/27] Control Flow Enforcement: Shadow Stack Yu-cheng Yu
2018-10-11 15:14 ` Yu-cheng Yu
2018-10-11 15:14 ` [PATCH v5 01/27] x86/cpufeatures: Add CPUIDs for Control Flow Enforcement Technology (CET) Yu-cheng Yu
2018-10-11 15:14 ` Yu-cheng Yu
2018-10-11 16:43 ` Borislav Petkov
2018-10-11 16:43 ` Borislav Petkov
2018-10-11 16:45 ` Yu-cheng Yu
2018-10-11 16:45 ` Yu-cheng Yu
2018-10-11 15:14 ` [PATCH v5 02/27] x86/fpu/xstate: Change names to separate XSAVES system and user states Yu-cheng Yu
2018-10-11 15:14 ` Yu-cheng Yu
2018-10-15 17:03 ` Borislav Petkov [this message]
2018-10-15 17:03 ` Borislav Petkov
2018-10-11 15:14 ` [PATCH v5 03/27] x86/fpu/xstate: Introduce XSAVES system states Yu-cheng Yu
2018-10-11 15:14 ` Yu-cheng Yu
2018-10-17 10:41 ` Borislav Petkov
2018-10-17 10:41 ` Borislav Petkov
2018-10-17 22:39 ` Randy Dunlap
2018-10-17 22:39 ` Randy Dunlap
2018-10-17 22:58 ` Borislav Petkov
2018-10-17 22:58 ` Borislav Petkov
2018-10-17 23:17 ` Randy Dunlap
2018-10-17 23:17 ` Randy Dunlap
2018-10-18 9:26 ` Borislav Petkov
2018-10-18 9:26 ` Borislav Petkov
2018-10-18 9:31 ` Pavel Machek
2018-10-18 9:31 ` Pavel Machek
2018-10-18 12:10 ` Borislav Petkov
2018-10-18 12:10 ` Borislav Petkov
2018-10-18 18:33 ` Randy Dunlap
2018-10-18 18:33 ` Randy Dunlap
2018-10-18 9:24 ` Pavel Machek
2018-10-18 9:24 ` Pavel Machek
2018-10-11 15:15 ` [PATCH v5 04/27] x86/fpu/xstate: Add XSAVES system states for shadow stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-11-08 18:40 ` Borislav Petkov
2018-11-08 18:40 ` Borislav Petkov
2018-11-08 20:40 ` Yu-cheng Yu
2018-11-08 20:40 ` Yu-cheng Yu
2018-11-08 23:52 ` Borislav Petkov
2018-11-08 23:52 ` Borislav Petkov
2018-11-11 11:31 ` Pavel Machek
2018-11-11 11:31 ` Pavel Machek
2018-11-11 11:31 ` Pavel Machek
2018-11-11 11:31 ` Pavel Machek
2018-11-11 14:59 ` Andy Lutomirski
2018-11-11 14:59 ` Andy Lutomirski
2018-11-11 19:02 ` Pavel Machek
2018-11-11 19:02 ` Pavel Machek
2018-11-08 20:46 ` Andy Lutomirski
2018-11-08 20:46 ` Andy Lutomirski
2018-11-08 21:01 ` Yu-cheng Yu
2018-11-08 21:01 ` Yu-cheng Yu
2018-11-08 21:22 ` Andy Lutomirski
2018-11-08 21:22 ` Andy Lutomirski
2018-11-08 21:31 ` Cyrill Gorcunov
2018-11-08 21:31 ` Cyrill Gorcunov
2018-11-08 22:01 ` Andy Lutomirski
2018-11-08 22:01 ` Andy Lutomirski
2018-11-08 22:18 ` Cyrill Gorcunov
2018-11-08 22:18 ` Cyrill Gorcunov
2018-11-08 21:48 ` Dave Hansen
2018-11-08 21:48 ` Dave Hansen
2018-11-08 22:00 ` Matthew Wilcox
2018-11-08 22:00 ` Matthew Wilcox
2018-11-08 23:35 ` Dave Hansen
2018-11-08 23:35 ` Dave Hansen
2018-11-09 0:32 ` Matthew Wilcox
2018-11-09 0:32 ` Matthew Wilcox
2018-11-09 0:45 ` Andy Lutomirski
2018-11-09 0:45 ` Andy Lutomirski
2018-11-09 17:13 ` Dave Hansen
2018-11-09 17:13 ` Dave Hansen
2018-11-09 17:17 ` Matthew Wilcox
2018-11-09 17:17 ` Matthew Wilcox
2018-11-09 17:20 ` Dave Hansen
2018-11-09 17:20 ` Dave Hansen
2018-11-09 17:28 ` Dave Hansen
2018-11-09 17:28 ` Dave Hansen
2018-11-11 11:31 ` Pavel Machek
2018-11-11 11:31 ` Pavel Machek
2018-10-11 15:15 ` [PATCH v5 05/27] Documentation/x86: Add CET description Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-11-13 18:43 ` Borislav Petkov
2018-11-13 18:43 ` Borislav Petkov
2018-11-13 21:02 ` Yu-cheng Yu
2018-11-13 21:02 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 06/27] x86/cet: Control protection exception handler Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-11-14 18:44 ` Borislav Petkov
2018-11-14 18:44 ` Borislav Petkov
2018-11-14 20:19 ` Yu-cheng Yu
2018-11-14 20:19 ` Yu-cheng Yu
2018-11-14 20:28 ` Borislav Petkov
2018-11-14 20:28 ` Borislav Petkov
2018-10-11 15:15 ` [PATCH v5 07/27] mm/mmap: Create a guard area between VMAs Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 20:39 ` Jann Horn
2018-10-11 20:39 ` Jann Horn
2018-10-11 20:49 ` Yu-cheng Yu
2018-10-11 20:49 ` Yu-cheng Yu
2018-10-11 20:55 ` Andy Lutomirski
2018-10-11 20:55 ` Andy Lutomirski
2018-10-12 21:49 ` Yu-cheng Yu
2018-10-12 21:49 ` Yu-cheng Yu
2018-10-12 13:17 ` Matthew Wilcox
2018-10-12 13:17 ` Matthew Wilcox
2018-10-11 20:49 ` Dave Hansen
2018-10-11 20:49 ` Dave Hansen
2018-10-12 10:24 ` Florian Weimer
2018-10-12 10:24 ` Florian Weimer
2018-10-11 15:15 ` [PATCH v5 08/27] x86/cet/shstk: Add Kconfig option for user-mode shadow stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 09/27] mm: Introduce VM_SHSTK for shadow stack memory Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 10/27] mm/mmap: Prevent Shadow Stack VMA merges Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 11/27] x86/mm: Change _PAGE_DIRTY to _PAGE_DIRTY_HW Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 12/27] x86/mm: Introduce _PAGE_DIRTY_SW Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 13/27] drm/i915/gvt: Update _PAGE_DIRTY to _PAGE_DIRTY_BITS Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 14/27] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 15/27] x86/mm: Shadow stack page fault error checking Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 16/27] mm: Handle shadow stack page fault Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 17/27] mm: Handle THP/HugeTLB " Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 18/27] mm: Update can_follow_write_pte/pmd for shadow stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 19/27] mm: Introduce do_mmap_locked() Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 20/27] x86/cet/shstk: User-mode shadow stack support Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 21/27] x86/cet/shstk: Introduce WRUSS instruction Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-11-06 18:43 ` Dave Hansen
2018-11-06 18:43 ` Dave Hansen
2018-11-06 18:55 ` Andy Lutomirski
2018-11-06 18:55 ` Andy Lutomirski
2018-11-06 20:21 ` Yu-cheng Yu
2018-11-06 20:21 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 22/27] x86/cet/shstk: Signal handling for shadow stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 23/27] x86/cet/shstk: ELF header parsing of Shadow Stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 24/27] x86/cet/shstk: Handle thread shadow stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 25/27] mm/mmap: Add Shadow stack pages to memory accounting Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 26/27] x86/cet/shstk: Add arch_prctl functions for Shadow Stack Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 15:15 ` [PATCH v5 27/27] x86/cet/shstk: Add Shadow Stack instructions to opcode map Yu-cheng Yu
2018-10-11 15:15 ` Yu-cheng Yu
2018-10-11 19:21 ` [PATCH v5 00/27] Control Flow Enforcement: Shadow Stack Dave Hansen
2018-10-11 19:21 ` Dave Hansen
2018-10-11 19:29 ` Yu-cheng Yu
2018-10-11 19:29 ` Yu-cheng Yu
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