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Index: sys/arm64/arm64/mp_machdep.c
===================================================================
--- sys/arm64/arm64/mp_machdep.c
+++ sys/arm64/arm64/mp_machdep.c
@@ -146,6 +146,13 @@
/* Set to 1 once we're ready to let the APs out of the pen. */
static volatile int aps_ready;
+static vm_offset_t pcpu_mem[MAXMEMDOM];
+static vm_offset_t pcpu_off[MAXMEMDOM];
+#ifdef INVARIANTS
+static int pcpu_alloc_id;
+vm_offset_t pcpu_allocations[MAXCPU];
+#endif
+
/* Temporary variables for init_secondary() */
void *dpcpu[MAXCPU - 1];
@@ -484,6 +491,49 @@
return (1);
}
+/*
+ * Allocate memory for the PCPU and DPCPU data. We allocate a level 2
+ * sized and aligned region so later allocations won't cause this memory
+ * to be promoted to a level 2 block. This can cause recursive exceptions
+ * as the exception handler needs to dereference the PCPU region and
+ * the promotion code needs to temporary mark the mapping invalid in the
+ * page table before marking the new level 2 block valid. This is normally
+ * fine as this is fast so the memory has been remapped by the time the
+ * exception handler is run, however when running on a VM we may exit to the
+ * host while this mapping is invalid meaning the memory is not remapped
+ * in time.
+ *
+ * Work around this by making sure the allocation takes an entire level 2
+ * block so won't be promoted. To reduce the wasted memory reuse this for
+ * as many CPUs in the same comain as possible.
+ */
+static vm_offset_t
+alloc_pcpu(int domain, vm_size_t size)
+{
+ vm_offset_t addr;
+
+ domain = domain % MAXMEMDOM;
+
+ if (pcpu_mem[domain] == 0 ||
+ (pcpu_off[domain] + size) >= (pcpu_mem[domain] + L2_SIZE)) {
+ pcpu_mem[domain] = kmem_alloc_contig_domainset(
+ DOMAINSET_PREF(domain), L2_SIZE, M_WAITOK | M_ZERO,
+ 0, ~(vm_paddr_t)0, L2_SIZE, 0, VM_MEMATTR_DEFAULT);
+ pcpu_off[domain] = pcpu_mem[domain];
+#ifdef INVARIANTS
+ /* Record the allocation to check we don't promote it */
+ pcpu_allocations[pcpu_alloc_id] = pcpu_mem[domain];
+ pcpu_alloc_id++;
+#endif
+ }
+
+ addr = pcpu_off[domain];
+ /* Align the next allocation */
+ pcpu_off[domain] = roundup2(addr + size, _Alignof(void *));
+
+ return (addr);
+}
+
/*
* Starts a given CPU. If the CPU is already running, i.e. it is the boot CPU,
* do nothing. Returns true if the CPU is present and running.
@@ -505,13 +555,11 @@
KASSERT(cpuid < MAXCPU, ("Too many CPUs"));
- pcpup = (void *)kmem_malloc_domainset(DOMAINSET_PREF(domain),
- sizeof(*pcpup), M_WAITOK | M_ZERO);
+ pcpup = (void *)alloc_pcpu(domain, sizeof(*pcpup));
pcpu_init(pcpup, cpuid, sizeof(struct pcpu));
pcpup->pc_mpidr = target_cpu & CPU_AFF_MASK;
- dpcpu[cpuid - 1] = (void *)kmem_malloc_domainset(
- DOMAINSET_PREF(domain), DPCPU_SIZE, M_WAITOK | M_ZERO);
+ dpcpu[cpuid - 1] = (void *)alloc_pcpu(domain, DPCPU_SIZE);
dpcpu_init(dpcpu[cpuid - 1], cpuid);
bootstacks[cpuid] = (void *)kmem_malloc_domainset(
@@ -535,7 +583,6 @@
cpuid, target_cpu, err));
pcpu_destroy(pcpup);
- kmem_free((vm_offset_t)dpcpu[cpuid - 1], DPCPU_SIZE);
dpcpu[cpuid - 1] = NULL;
kmem_free((vm_offset_t)bootstacks[cpuid], PAGE_SIZE);
bootstacks[cpuid] = NULL;
Index: sys/arm64/arm64/pmap.c
===================================================================
--- sys/arm64/arm64/pmap.c
+++ sys/arm64/arm64/pmap.c
@@ -3639,6 +3639,20 @@
PMAP_LOCK_ASSERT(pmap, MA_OWNED);
+#ifdef INVARIANTS
+ for (int i = 0; i < MAXCPU && pcpu_allocations[i] != 0; i++) {
+ if (va < pcpu_allocations[i]) {
+ KASSERT(va + size < pcpu_allocations[i],
+ ("%s: Updating start of pcpu: %lx-%lx %lx",
+ __func__, va, va + size, pcpu_allocations[i]));
+ } else {
+ KASSERT(va >= pcpu_allocations[i] + L2_SIZE,
+ ("%s: Updating end of pcpu: %lx-%lx %lx", __func__,
+ va, va+size, pcpu_allocations[i] + L2_SIZE));
+ }
+ }
+#endif
+
/*
* Ensure we don't get switched out with the page table in an
* inconsistent state. We also need to ensure no interrupts fire
Index: sys/arm64/include/machdep.h
===================================================================
--- sys/arm64/include/machdep.h
+++ sys/arm64/include/machdep.h
@@ -48,6 +48,11 @@
ARM64_BUS_ACPI,
};
+/* Used by pmap.c to check we don't promote/demote any pcpu memory */
+#ifdef INVARIANTS
+extern vm_offset_t pcpu_allocations[MAXCPU];
+#endif
+
extern enum arm64_bus arm64_bus_method;
void dbg_init(void);

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