diff options
| -rw-r--r-- | include/linux/rseq_types.h | 4 | ||||
| -rw-r--r-- | include/linux/sched.h | 6 | ||||
| -rw-r--r-- | kernel/sched/core.c | 10 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 59 |
4 files changed, 75 insertions, 4 deletions
diff --git a/include/linux/rseq_types.h b/include/linux/rseq_types.h index 574aba6fe97c..87854effe1ad 100644 --- a/include/linux/rseq_types.h +++ b/include/linux/rseq_types.h @@ -92,7 +92,9 @@ struct rseq_data { }; #ifdef CONFIG_SCHED_MM_CID -#define MM_CID_UNSET (~0U) +#define MM_CID_UNSET BIT(31) +#define MM_CID_ONCPU BIT(30) +#define MM_CID_TRANSIT BIT(29) /** * struct sched_mm_cid - Storage for per task MM CID data diff --git a/include/linux/sched.h b/include/linux/sched.h index c411ae021bc5..9eec409745f8 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2299,16 +2299,16 @@ void sched_mm_cid_before_execve(struct task_struct *t); void sched_mm_cid_after_execve(struct task_struct *t); void sched_mm_cid_fork(struct task_struct *t); void sched_mm_cid_exit(struct task_struct *t); -static inline int task_mm_cid(struct task_struct *t) +static __always_inline int task_mm_cid(struct task_struct *t) { - return t->mm_cid.cid; + return t->mm_cid.cid & ~(MM_CID_ONCPU | MM_CID_TRANSIT); } #else static inline void sched_mm_cid_before_execve(struct task_struct *t) { } static inline void sched_mm_cid_after_execve(struct task_struct *t) { } static inline void sched_mm_cid_fork(struct task_struct *t) { } static inline void sched_mm_cid_exit(struct task_struct *t) { } -static inline int task_mm_cid(struct task_struct *t) +static __always_inline int task_mm_cid(struct task_struct *t) { /* * Use the processor id as a fall-back when the mm cid feature is diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 01903cf03ab2..55bb9c9ae32c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -10386,6 +10386,16 @@ void call_trace_sched_update_nr_running(struct rq *rq, int count) * * The mm::mm_cid:pcpu per CPU storage is protected by the CPUs runqueue * lock. + * + * CID ownership: + * + * A CID is either owned by a task (stored in task_struct::mm_cid.cid) or + * by a CPU (stored in mm::mm_cid.pcpu::cid). CIDs owned by CPUs have the + * MM_CID_ONCPU bit set. During transition from CPU to task ownership mode, + * MM_CID_TRANSIT is set on the per task CIDs. When this bit is set the + * task needs to drop the CID into the pool when scheduling out. Both bits + * (ONCPU and TRANSIT) are filtered out by task_cid() when the CID is + * actually handed over to user space in the RSEQ memory. */ /* diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index d539fb269957..4b49284504fb 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -3540,6 +3540,65 @@ extern void sched_dynamic_update(int mode); extern const char *preempt_modes[]; #ifdef CONFIG_SCHED_MM_CID + +static __always_inline bool cid_on_cpu(unsigned int cid) +{ + return cid & MM_CID_ONCPU; +} + +static __always_inline bool cid_in_transit(unsigned int cid) +{ + return cid & MM_CID_TRANSIT; +} + +static __always_inline unsigned int cpu_cid_to_cid(unsigned int cid) +{ + return cid & ~MM_CID_ONCPU; +} + +static __always_inline unsigned int cid_to_cpu_cid(unsigned int cid) +{ + return cid | MM_CID_ONCPU; +} + +static __always_inline unsigned int cid_to_transit_cid(unsigned int cid) +{ + return cid | MM_CID_TRANSIT; +} + +static __always_inline unsigned int cid_from_transit_cid(unsigned int cid) +{ + return cid & ~MM_CID_TRANSIT; +} + +static __always_inline bool cid_on_task(unsigned int cid) +{ + /* True if none of the MM_CID_ONCPU, MM_CID_TRANSIT, MM_CID_UNSET bits is set */ + return cid < MM_CID_TRANSIT; +} + +static __always_inline void mm_drop_cid(struct mm_struct *mm, unsigned int cid) +{ + clear_bit(cid, mm_cidmask(mm)); +} + +static __always_inline void mm_unset_cid_on_task(struct task_struct *t) +{ + unsigned int cid = t->mm_cid.cid; + + t->mm_cid.cid = MM_CID_UNSET; + if (cid_on_task(cid)) + mm_drop_cid(t->mm, cid); +} + +static __always_inline void mm_drop_cid_on_cpu(struct mm_struct *mm, struct mm_cid_pcpu *pcp) +{ + /* Clear the ONCPU bit, but do not set UNSET in the per CPU storage */ + pcp->cid = cpu_cid_to_cid(pcp->cid); + mm_drop_cid(mm, pcp->cid); +} + +/* Active implementation */ static inline void init_sched_mm_cid(struct task_struct *t) { struct mm_struct *mm = t->mm; |