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diff --git a/sys/arm64/arm64/trap.c b/sys/arm64/arm64/trap.c
--- a/sys/arm64/arm64/trap.c
+++ b/sys/arm64/arm64/trap.c
@@ -246,7 +246,6 @@
uint64_t far, int lower)
{
struct vm_map *map;
- struct proc *p;
struct pcb *pcb;
vm_prot_t ftype;
int error, sig, ucode;
@@ -268,28 +267,44 @@
}
#endif
- pcb = td->td_pcb;
- p = td->td_proc;
- if (lower)
- map = &p->p_vmspace->vm_map;
- else {
- intr_enable();
-
+ if (lower) {
+ map = &td->td_proc->p_vmspace->vm_map;
+ } else if (!ADDR_IS_CANONICAL(far)) {
/* We received a TBI/PAC/etc. fault from the kernel */
- if (!ADDR_IS_CANONICAL(far)) {
- error = KERN_INVALID_ADDRESS;
- goto bad_far;
+ error = KERN_INVALID_ADDRESS;
+ goto bad_far;
+ } else if (ADDR_IS_KERNEL(far)) {
+ /*
+ * Handle a special case: the data abort was caused by accessing
+ * a thread structure while its mapping was being promoted or
+ * demoted, as a consequence of the break-before-make rule. It
+ * is not safe to enable interrupts or dereference "td" before
+ * this case is handled.
+ *
+ * In principle, if pmap_klookup() fails, there is no need to
+ * call pmap_fault() below, but avoiding that call is not worth
+ * the effort.
+ */
+ if (ESR_ELx_EXCEPTION(esr) == EXCP_DATA_ABORT) {
+ switch (esr & ISS_DATA_DFSC_MASK) {
+ case ISS_DATA_DFSC_TF_L0:
+ case ISS_DATA_DFSC_TF_L1:
+ case ISS_DATA_DFSC_TF_L2:
+ case ISS_DATA_DFSC_TF_L3:
+ if (pmap_klookup(far, NULL))
+ return;
+ break;
+ }
}
-
- /* The top bit tells us which range to use */
- if (ADDR_IS_KERNEL(far)) {
+ intr_enable();
+ map = kernel_map;
+ } else {
+ intr_enable();
+ map = &td->td_proc->p_vmspace->vm_map;
+ if (map == NULL)
map = kernel_map;
- } else {
- map = &p->p_vmspace->vm_map;
- if (map == NULL)
- map = kernel_map;
- }
}
+ pcb = td->td_pcb;
/*
* Try to handle translation, access flag, and permission faults.
@@ -334,11 +349,11 @@
/* Fault in the page. */
error = vm_fault_trap(map, far, ftype, VM_FAULT_NORMAL, &sig, &ucode);
if (error != KERN_SUCCESS) {
-bad_far:
if (lower) {
call_trapsignal(td, sig, ucode, (void *)far,
ESR_ELx_EXCEPTION(esr));
} else {
+bad_far:
if (td->td_intr_nesting_level == 0 &&
pcb->pcb_onfault != 0) {
frame->tf_x[0] = error;
diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -503,7 +503,6 @@
{
u_long i;
lwpid_t tid0;
- uint32_t flags;
/*
* Place an upper limit on threads which can be allocated.
@@ -531,20 +530,9 @@
if (tid0 != THREAD0_TID)
panic("tid0 %d != %d\n", tid0, THREAD0_TID);
- flags = UMA_ZONE_NOFREE;
-#ifdef __aarch64__
- /*
- * Force thread structures to be allocated from the direct map.
- * Otherwise, superpage promotions and demotions may temporarily
- * invalidate thread structure mappings. For most dynamically allocated
- * structures this is not a problem, but translation faults cannot be
- * handled without accessing curthread.
- */
- flags |= UMA_ZONE_CONTIG;
-#endif
thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
thread_ctor, thread_dtor, thread_init, thread_fini,
- 32 - 1, flags);
+ 32 - 1, UMA_ZONE_NOFREE);
tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
tidhashlock = (tidhash + 1) / 64;
if (tidhashlock > 0)

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