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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-08-30 15:00:33 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-08-30 15:00:33 -0700 |
| commit | 0a096f240aa1992ddac65f8e704f7b0c0795fe1c (patch) | |
| tree | 04c64aca17b94b0862214e09784fc23b413df578 /include | |
| parent | 7d6e3fa87e732ec1e7761bf325c0907685c8571b (diff) | |
| parent | b7fe54f6c2d437082dcbecfbd832f38edd9caaf4 (diff) | |
Merge tag 'x86-cpu-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cache flush updates from Thomas Gleixner:
"A reworked version of the opt-in L1D flush mechanism.
This is a stop gap for potential future speculation related hardware
vulnerabilities and a mechanism for truly security paranoid
applications.
It allows a task to request that the L1D cache is flushed when the
kernel switches to a different mm. This can be requested via prctl().
Changes vs the previous versions:
- Get rid of the software flush fallback
- Make the handling consistent with other mitigations
- Kill the task when it ends up on a SMT enabled core which defeats
the purpose of L1D flushing obviously"
* tag 'x86-cpu-2021-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation: Add L1D flushing Documentation
x86, prctl: Hook L1D flushing in via prctl
x86/mm: Prepare for opt-in based L1D flush in switch_mm()
x86/process: Make room for TIF_SPEC_L1D_FLUSH
sched: Add task_work callback for paranoid L1D flush
x86/mm: Refactor cond_ibpb() to support other use cases
x86/smp: Add a per-cpu view of SMT state
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 10 | ||||
| -rw-r--r-- | include/uapi/linux/prctl.h | 1 |
2 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index af7179f8572c..1780260f237b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1474,6 +1474,16 @@ 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. diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 967d9c55323d..964c41ed303e 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -213,6 +213,7 @@ struct prctl_mm_map { /* Speculation control variants */ # define PR_SPEC_STORE_BYPASS 0 # define PR_SPEC_INDIRECT_BRANCH 1 +# define PR_SPEC_L1D_FLUSH 2 /* Return and control values for PR_SET/GET_SPECULATION_CTRL */ # define PR_SPEC_NOT_AFFECTED 0 # define PR_SPEC_PRCTL (1UL << 0) |