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authorThomas Gleixner <tglx@linutronix.de>2018-05-04 15:12:06 +0200
committerThomas Gleixner <tglx@linutronix.de>2018-05-05 00:51:44 +0200
commit8bf37d8c067bb7eb8e7c381bdadf9bd89182b6bc (patch)
treeac991511615d563b0141782cba95fc2482a68afc /kernel/seccomp.c
parent00a02d0c502a06d15e07b857f8ff921e3e402675 (diff)
downloadlinux-stericsson-8bf37d8c067bb7eb8e7c381bdadf9bd89182b6bc.tar.gz
seccomp: Move speculation migitation control to arch code
The migitation control is simpler to implement in architecture code as it avoids the extra function call to check the mode. Aside of that having an explicit seccomp enabled mode in the architecture mitigations would require even more workarounds. Move it into architecture code and provide a weak function in the seccomp code. Remove the 'which' argument as this allows the architecture to decide which mitigations are relevant for seccomp. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/seccomp.c')
-rw-r--r--kernel/seccomp.c15
1 files changed, 2 insertions, 13 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 53eb946120c1..e691d9a6c58d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -229,18 +229,7 @@ static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
return true;
}
-/*
- * If a given speculation mitigation is opt-in (prctl()-controlled),
- * select it, by disabling speculation (enabling mitigation).
- */
-static inline void spec_mitigate(struct task_struct *task,
- unsigned long which)
-{
- int state = arch_prctl_spec_ctrl_get(task, which);
-
- if (state > 0 && (state & PR_SPEC_PRCTL))
- arch_prctl_spec_ctrl_set(task, which, PR_SPEC_FORCE_DISABLE);
-}
+void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { }
static inline void seccomp_assign_mode(struct task_struct *task,
unsigned long seccomp_mode,
@@ -256,7 +245,7 @@ static inline void seccomp_assign_mode(struct task_struct *task,
smp_mb__before_atomic();
/* Assume default seccomp processes want spec flaw mitigation. */
if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0)
- spec_mitigate(task, PR_SPEC_STORE_BYPASS);
+ arch_seccomp_spec_mitigate(task);
set_tsk_thread_flag(task, TIF_SECCOMP);
}