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From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
To: linux-kernel@vger.kernel.org
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
	Aaron Lu <aaron.lwe@gmail.com>,
	Aubrey Li <aubrey.li@linux.intel.com>,
	Julien Desfossez <jdesfossez@digitalocean.com>,
	Kees Cook <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Paul Turner <pjt@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Tim Chen <tim.c.chen@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Vineeth Pillai <viremana@linux.microsoft.com>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	fweisbec@gmail.com, kerrnel@google.com,
	Phil Auld <pauld@redhat.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Chen Yu <yu.c.chen@intel.com>,
	Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH RFC 03/12] arch/x86: Add a new TIF flag for untrusted tasks
Date: Fri, 14 Aug 2020 23:18:59 -0400
Message-ID: <20200815031908.1015049-4-joel@joelfernandes.org> (raw)
In-Reply-To: <20200815031908.1015049-1-joel@joelfernandes.org>

Add a new TIF flag to indicate whether the kernel needs to be careful
and take additional steps to mitigate micro-architectural issues during
entry into user or guest mode.

This new flag will be used by the series to determine if waiting is
needed or not, during exit to user or guest mode.

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 arch/x86/include/asm/thread_info.h | 2 ++
 kernel/sched/sched.h               | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 267701ae3d86..42e63969acb3 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -98,6 +98,7 @@ struct thread_info {
 #define TIF_IO_BITMAP		22	/* uses I/O bitmap */
 #define TIF_FORCED_TF		24	/* true if TF in eflags artificially */
 #define TIF_BLOCKSTEP		25	/* set when we want DEBUGCTLMSR_BTF */
+#define TIF_UNSAFE_RET   	26	/* On return to process/guest, perform safety checks. */
 #define TIF_LAZY_MMU_UPDATES	27	/* task is updating the mmu lazily */
 #define TIF_SYSCALL_TRACEPOINT	28	/* syscall tracepoint instrumentation */
 #define TIF_ADDR32		29	/* 32-bit address space on 64 bits */
@@ -127,6 +128,7 @@ struct thread_info {
 #define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)
 #define _TIF_FORCED_TF		(1 << TIF_FORCED_TF)
 #define _TIF_BLOCKSTEP		(1 << TIF_BLOCKSTEP)
+#define _TIF_UNSAFE_RET 	(1 << TIF_UNSAFE_RET)
 #define _TIF_LAZY_MMU_UPDATES	(1 << TIF_LAZY_MMU_UPDATES)
 #define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
 #define _TIF_ADDR32		(1 << TIF_ADDR32)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 3575edc7dc43..1901d11a6f41 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2680,3 +2680,9 @@ static inline bool is_per_cpu_kthread(struct task_struct *p)
 
 void swake_up_all_locked(struct swait_queue_head *q);
 void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
+
+#ifdef CONFIG_SCHED_CORE
+#ifndef TIF_UNSAFE_RET
+#define TIF_UNSAFE_RET (0)
+#endif
+#endif
-- 
2.28.0.220.ged08abb693-goog


  parent reply index

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-15  3:18 [PATCH RFC 00/12] Core-sched v6+: kernel protection and hotplug fixes Joel Fernandes (Google)
2020-08-15  3:18 ` [PATCH RFC 01/12] irq_work: Add support to detect if work is pending Joel Fernandes (Google)
2020-08-15  8:13   ` peterz
2020-08-17  2:04     ` Joel Fernandes
2020-08-15  3:18 ` [PATCH RFC 02/12] entry/idle: Add a common function for activites during idle entry/exit Joel Fernandes (Google)
2020-08-15  8:14   ` peterz
2020-08-17  2:17     ` Joel Fernandes
2020-08-15  3:18 ` Joel Fernandes (Google) [this message]
2020-08-15  3:19 ` [PATCH RFC 04/12] kernel/entry: Add support for core-wide protection of kernel-mode Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 05/12] entry/idle: Enter and exit kernel protection during idle entry and exit Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 06/12] entry/kvm: Protect the kernel when entering from guest Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 07/12] bitops: Introduce find_next_or_bit Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 08/12] cpumask: Introduce a new iterator for_each_cpu_wrap_or Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 09/12] sched/coresched: Use for_each_cpu(_wrap)_or for pick_next_task Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 10/12] sched/coresched: Make core_pick_seq per run-queue Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 11/12] sched/coresched: Check for dynamic changes in smt_mask Joel Fernandes (Google)
2020-08-15  3:19 ` [PATCH RFC 12/12] sched/coresched: rq->core should be set only if not previously set Joel Fernandes (Google)
2020-08-19 18:26 ` [PATCH RFC 00/12] Core-sched v6+: kernel protection and hotplug fixes Kees Cook
2020-08-20  1:44   ` Joel Fernandes
2020-08-22 20:22 ` Joel Fernandes

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