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Split out vfp_new_thread

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To keep the vfp thread creation code in one place move into vfp.c. This
will also help with adding SVE support as it depends on VFP.

Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D35615
This commit is contained in:
Andrew Turner 2022-06-24 11:53:15 +00:00
parent cf337fcd74
commit baf8f20a4a
3 changed files with 32 additions and 5 deletions
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26
sys/arm64/arm64/vfp.c
View File

@ -199,6 +199,32 @@ vfp_save_state(struct thread *td, struct pcb *pcb)
critical_exit();
}
/*
* Update the VFP state for a forked process or new thread. The PCB will
* have been copied from the old thread.
*/
void
vfp_new_thread(struct thread *newtd, struct thread *oldtd, bool fork)
{
struct pcb *newpcb;
newpcb = newtd->td_pcb;
/* Kernel threads start with clean VFP */
if ((oldtd->td_pflags & TDP_KTHREAD) != 0) {
newpcb->pcb_fpflags &=
~(PCB_FP_STARTED | PCB_FP_KERN | PCB_FP_NOSAVE);
} else {
MPASS((newpcb->pcb_fpflags & (PCB_FP_KERN|PCB_FP_NOSAVE)) == 0);
if (!fork) {
newpcb->pcb_fpflags &= ~PCB_FP_STARTED;
}
}
newpcb->pcb_fpusaved = &newpcb->pcb_fpustate;
newpcb->pcb_vfpcpu = UINT_MAX;
}
/*
* Reset the FP state to avoid leaking state from the parent process across
* execve() (and to ensure that we get a consistent floating point environment

10
sys/arm64/arm64/vm_machdep.c
View File

@ -109,8 +109,8 @@ cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
td2->td_pcb->pcb_x[20] = (uintptr_t)td2;
td2->td_pcb->pcb_lr = (uintptr_t)fork_trampoline;
td2->td_pcb->pcb_sp = (uintptr_t)td2->td_frame;
td2->td_pcb->pcb_fpusaved = &td2->td_pcb->pcb_fpustate;
td2->td_pcb->pcb_vfpcpu = UINT_MAX;
vfp_new_thread(td2, td1, true);
/* Setup to release spin count in fork_exit(). */
td2->td_md.md_spinlock_count = 1;
@ -187,9 +187,9 @@ cpu_copy_thread(struct thread *td, struct thread *td0)
td->td_pcb->pcb_x[20] = (uintptr_t)td;
td->td_pcb->pcb_lr = (uintptr_t)fork_trampoline;
td->td_pcb->pcb_sp = (uintptr_t)td->td_frame;
td->td_pcb->pcb_fpflags &= ~(PCB_FP_STARTED | PCB_FP_KERN | PCB_FP_NOSAVE);
td->td_pcb->pcb_fpusaved = &td->td_pcb->pcb_fpustate;
td->td_pcb->pcb_vfpcpu = UINT_MAX;
/* Update VFP state for the new thread */
vfp_new_thread(td, td0, false);
/* Setup to release spin count in fork_exit(). */
td->td_md.md_spinlock_count = 1;

1
sys/arm64/include/vfp.h
View File

@ -68,6 +68,7 @@ struct thread;
void vfp_init(void);
void vfp_discard(struct thread *);
void vfp_new_thread(struct thread *, struct thread *, bool);
void vfp_reset_state(struct thread *, struct pcb *);
void vfp_restore_state(void);
void vfp_save_state(struct thread *, struct pcb *);