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 18/24] kernel/task: Add a helper to get the thread_union
Date: Wed, 21 Oct 2026 12:51:45 -0700 [thread overview]
Message-ID: <20261021195145.40C0CF76@davehans-spike.ostc.intel.com> (raw)
In-Reply-To: <20261021195120.E61EC737@davehans-spike.ostc.intel.com>
There's currently no helper that, given a task, can work back to the
"outer" thread_union. Add one to help locating the shadow stack
mapping location.
---
b/include/linux/sched/task_stack.h | 5 +++++
1 file changed, 5 insertions(+)
diff -puN include/linux/sched/task_stack.h~generic-task_thread_union include/linux/sched/task_stack.h
--- a/include/linux/sched/task_stack.h~generic-task_thread_union 2026-10-21 12:36:41.575888044 -0700
+++ b/include/linux/sched/task_stack.h 2026-10-21 12:36:41.577888048 -0700
@@ -23,6 +23,11 @@ static __always_inline void *task_stack_
return task->stack;
}
+static inline union thread_union *task_thread_union(struct task_struct *tsk)
+{
+ return (union thread_union *)task_stack_page(tsk);
+}
+
#define setup_thread_stack(new,old) do { } while(0)
static __always_inline unsigned long *end_of_stack(const struct task_struct *task)
_
next prev parent reply other threads:[~2026-10-21 19:51 UTC|newest]
Thread overview: 29+ 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 22:59 ` Dave Hansen
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 ` [RFC][PATCH 15/24] x86/task: Hook up arch hook to detect shadow stack enabling Dave Hansen
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 ` Dave Hansen [this message]
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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