3 files changed, 15 insertions, 3 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 8927c878544d..a7c80a6e8622 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -123,6 +123,8 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 {
         unsigned long pfn, offset, vaddr;
         resource_size_t last_addr;
+        const resource_size_t unaligned_phys_addr = phys_addr;
+        const unsigned long unaligned_size = size;
         struct vm_struct *area;
         unsigned long new_prot_val;
         pgprot_t prot;
@@ -236,7 +238,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
         }
 
         ret_addr = (void __iomem *) (vaddr + offset);
-        mmiotrace_ioremap(phys_addr, size, ret_addr);
+        mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);
 
         return ret_addr;
 }
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 6a92d9111b64..93b1797666cb 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -351,11 +351,19 @@ static void release_kmmio_fault_page(unsigned long page,
         }
 }
 
+/*
+ * With page-unaligned ioremaps, one or two armed pages may contain
+ * addresses from outside the intended mapping. Events for these addresses
+ * are currently silently dropped. The events may result only from programming
+ * mistakes by accessing addresses before the beginning or past the end of a
+ * mapping.
+ */
 int register_kmmio_probe(struct kmmio_probe *p)
 {
         unsigned long flags;
         int ret = 0;
         unsigned long size = 0;
+        const unsigned long size_lim = p->len + (p->addr & ~PAGE_MASK);
 
         spin_lock_irqsave(&kmmio_lock, flags);
         if (get_kmmio_probe(p->addr)) {
@@ -364,7 +372,7 @@ int register_kmmio_probe(struct kmmio_probe *p)
         }
         kmmio_count++;
         list_add_rcu(&p->list, &kmmio_probes);
-        while (size < p->len) {
+        while (size < size_lim) {
                 if (add_kmmio_fault_page(p->addr + size))
                         pr_err("kmmio: Unable to set page fault.\n");
                 size += PAGE_SIZE;
@@ -436,11 +444,12 @@ void unregister_kmmio_probe(struct kmmio_probe *p)
 {
         unsigned long flags;
         unsigned long size = 0;
+        const unsigned long size_lim = p->len + (p->addr & ~PAGE_MASK);
         struct kmmio_fault_page *release_list = NULL;
         struct kmmio_delayed_release *drelease;
 
         spin_lock_irqsave(&kmmio_lock, flags);
-        while (size < p->len) {
+        while (size < size_lim) {
                 release_kmmio_fault_page(p->addr + size, &release_list);
                 size += PAGE_SIZE;
         }
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index a8d2a0019da4..278998c1998f 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -280,6 +280,7 @@ static void ioremap_trace_core(unsigned long offset, unsigned long size,
 {
         static atomic_t next_id;
         struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
+        /* These are page-unaligned. */
         struct mmiotrace_map map = {
                 .phys = offset,
                 .virt = (unsigned long)addr,