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From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Edgecombe, Rick P <rick.p.edgecombe@intel.com>,
	Andrew Cooper <andrew.cooper3@citrix.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Kees Cook <kees@kernel.org>,
	Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
	Borislav Petkov <bp@alien8.de>, Thomas Gleixner <tglx@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>
Subject: [RFC][PATCH 15/24] x86/task: Hook up arch hook to detect shadow stack enabling
Date: Wed, 21 Oct 2026 12:51:41 -0700	[thread overview]
Message-ID: <20261021195141.2A1FD9F9@davehans-spike.ostc.intel.com> (raw)
In-Reply-To: <20261021195120.E61EC737@davehans-spike.ostc.intel.com>


Provide an x86 definition for arch_kernel_shstk_enabled(), used in the
generic code to skip any attempts to clear shadow stack pages.

---

 b/arch/x86/include/asm/thread_info.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff -puN arch/x86/include/asm/thread_info.h~x86-shadow-stacks-enabled arch/x86/include/asm/thread_info.h
--- a/arch/x86/include/asm/thread_info.h~x86-shadow-stacks-enabled	2026-10-21 12:36:39.920884876 -0700
+++ b/arch/x86/include/asm/thread_info.h	2026-10-21 12:36:39.922884879 -0700
@@ -231,6 +231,12 @@ extern void arch_setup_new_exec(void);
 struct thread_stacks;
 extern void arch_init_thread_stacks(struct thread_stacks *ts);
 #define arch_init_thread_stacks arch_init_thread_stacks
+
+static inline bool arch_kernel_shstk_enabled(void)
+{
+	return cpu_feature_enabled(X86_FEATURE_KERN_SHSTK);
+}
+#define arch_kernel_shstk_enabled arch_kernel_shstk_enabled
 #endif
 
 #endif	/* !__ASSEMBLER__ */
_

  parent reply	other threads:[~2026-10-21 19:51 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-21 19:51 [RFC][PATCH 00/24] x86 Kernel Shadow Stacks Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 01/24] kernel/fork: Break out vmap task allocation into helper Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 02/24] kernel/fork: Use sizeof() union instead of TASK_SIZE Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 03/24] kernel/sched: Move thread stack to its own structure Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 04/24] kernel/fork: Allow arch-specific stack initialization Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 05/24] kernel/task: Add shadow stack to thread structure Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 06/24] kernel/task: Add "runtime" check for shadow stack support Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 07/24] kernel/fork: Clear shadow stacks alongside normal stacks Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 08/24] x86/cpu: Add basic x86 kernel shadow stack infrastructure Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 09/24] x86/cea: Refactor "CEA" macros to deal with multiple stacks Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 10/24] x86/cea: Refactor stack mapping macros Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 11/24] x86/mm: Add kernel shadow stack permission macros Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 12/24] x86/cea: Map and use FRED exception shadow stacks Dave Hansen
2026-10-21 21:40   ` Peter Zijlstra
2026-10-21 19:51 ` [RFC][PATCH 13/24] x86/task: Grow thread_union for " Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 14/24] x86/mm: Establish shadow stack permissions in thread mapping Dave Hansen
2026-10-21 19:51 ` Dave Hansen [this message]
2026-10-21 19:51 ` [RFC][PATCH 16/24] x86/mm: Kill shadow stack page permission warning Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 17/24] x86/task: Context switch the kernel shadow stack register value Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 18/24] kernel/task: Add a helper to get the thread_union Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 19/24] x86/process: Initialize cloned task shadow stack Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 20/24] x86/entry: Stash kernel SSP on FRED entry Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 21/24] x86/extable: Update shadow stack entry frame during RIP overwrites Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 22/24] kernel/task: Add a helper to locate the top of the shadow stack Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 23/24] x86/entry: Populate FRED register for user=>kernel transitions Dave Hansen
2026-10-21 19:51 ` [RFC][PATCH 24/24] [DO NOT MERGE] x86/shstk: Depend out everything incompatible with kernel shadow stacks Dave Hansen
2026-10-21 21:36 ` [RFC][PATCH 00/24] x86 Kernel Shadow Stacks Peter Zijlstra
2026-10-21 21:53 ` Peter Zijlstra

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