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| author |   Balbir Singh <sblbir@amazon.com> | 2021-04-26 21:59:11 +0200 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2021-07-28 11:42:24 +0200 |
| commit | 58e106e725eed59896b9141a1c9a917d2f67962a (patch) | |
| tree | ed070e440c19cd31bd32342673065af6b48f636d | |
| parent | x86/mm: Refactor cond_ibpb() to support other use cases (diff) | |
| download | linux-dev-58e106e725eed59896b9141a1c9a917d2f67962a.tar.xz linux-dev-58e106e725eed59896b9141a1c9a917d2f67962a.zip | |
sched: Add task_work callback for paranoid L1D flush
The upcoming paranoid L1D flush infrastructure allows to conditionally
(opt-in) flush L1D in switch_mm() as a defense against potential new side
channels or for paranoia reasons. As the flush makes only sense when a task
runs on a non-SMT enabled core, because SMT siblings share L1, the
switch_mm() logic will kill a task which is flagged for L1D flush when it
is running on a SMT thread.
Add a taskwork callback so switch_mm() can queue a SIG_KILL command which
is invoked when the task tries to return to user space.
Signed-off-by: Balbir Singh <sblbir@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210108121056.21940-1-sblbir@amazon.com
| -rw-r--r-- | arch/Kconfig | 3 | ||||
| -rw-r--r-- | include/linux/sched.h | 10 |
2 files changed, 13 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 129df498a8e1..98db63496bab 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1282,6 +1282,9 @@ config ARCH_SPLIT_ARG64 config ARCH_HAS_ELFCORE_COMPAT bool +config ARCH_HAS_PARANOID_L1D_FLUSH + bool + source "kernel/gcov/Kconfig" source "scripts/gcc-plugins/Kconfig" diff --git a/include/linux/sched.h b/include/linux/sched.h index ec8d07d88641..c048e59d3fbd 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1400,6 +1400,16 @@ struct task_struct { struct llist_head kretprobe_instances; #endif +#ifdef CONFIG_ARCH_HAS_PARANOID_L1D_FLUSH + /* + * If L1D flush is supported on mm context switch + * then we use this callback head to queue kill work + * to kill tasks that are not running on SMT disabled + * cores + */ + struct callback_head l1d_flush_kill; +#endif + /* * New fields for task_struct should be added above here, so that * they are included in the randomized portion of task_struct. |