1 files changed, 33 insertions, 25 deletions

diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 16ccbd77917f..5d0e67fff1a6 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -5,6 +5,8 @@
  *     2008 Pekka Paalanen <pq@iki.fi>
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/spinlock.h>
@@ -19,6 +21,7 @@
 #include <linux/kdebug.h>
 #include <linux/mutex.h>
 #include <linux/io.h>
+#include <linux/slab.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 #include <linux/errno.h>
@@ -136,7 +139,7 @@ static int clear_page_presence(struct kmmio_fault_page *f, bool clear)
         pte_t *pte = lookup_address(f->page, &level);
 
         if (!pte) {
-                pr_err("kmmio: no pte for page 0x%08lx\n", f->page);
+                pr_err("no pte for page 0x%08lx\n", f->page);
                 return -1;
         }
 
@@ -148,7 +151,7 @@ static int clear_page_presence(struct kmmio_fault_page *f, bool clear)
                 clear_pte_presence(pte, clear, &f->old_presence);
                 break;
         default:
-                pr_err("kmmio: unexpected page level 0x%x.\n", level);
+                pr_err("unexpected page level 0x%x.\n", level);
                 return -1;
         }
 
@@ -170,13 +173,14 @@ static int clear_page_presence(struct kmmio_fault_page *f, bool clear)
 static int arm_kmmio_fault_page(struct kmmio_fault_page *f)
 {
         int ret;
-        WARN_ONCE(f->armed, KERN_ERR "kmmio page already armed.\n");
+        WARN_ONCE(f->armed, KERN_ERR pr_fmt("kmmio page already armed.\n"));
         if (f->armed) {
-                pr_warning("kmmio double-arm: page 0x%08lx, ref %d, old %d\n",
-                                        f->page, f->count, !!f->old_presence);
+                pr_warning("double-arm: page 0x%08lx, ref %d, old %d\n",
+                           f->page, f->count, !!f->old_presence);
         }
         ret = clear_page_presence(f, true);
-        WARN_ONCE(ret < 0, KERN_ERR "kmmio arming 0x%08lx failed.\n", f->page);
+        WARN_ONCE(ret < 0, KERN_ERR pr_fmt("arming 0x%08lx failed.\n"),
+                  f->page);
         f->armed = true;
         return ret;
 }
@@ -203,7 +207,7 @@ static void disarm_kmmio_fault_page(struct kmmio_fault_page *f)
  */
 /*
  * Interrupts are disabled on entry as trap3 is an interrupt gate
- * and they remain disabled thorough out this function.
+ * and they remain disabled throughout this function.
  */
 int kmmio_handler(struct pt_regs *regs, unsigned long addr)
 {
@@ -240,24 +244,21 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr)
                          * condition needs handling by do_page_fault(), the
                          * page really not being present is the most common.
                          */
-                        pr_debug("kmmio: secondary hit for 0x%08lx CPU %d.\n",
-                                        addr, smp_processor_id());
+                        pr_debug("secondary hit for 0x%08lx CPU %d.\n",
+                                 addr, smp_processor_id());
 
                         if (!faultpage->old_presence)
-                                pr_info("kmmio: unexpected secondary hit for "
-                                        "address 0x%08lx on CPU %d.\n", addr,
-                                        smp_processor_id());
+                                pr_info("unexpected secondary hit for address 0x%08lx on CPU %d.\n",
+                                        addr, smp_processor_id());
                 } else {
                         /*
                          * Prevent overwriting already in-flight context.
                          * This should not happen, let's hope disarming at
                          * least prevents a panic.
                          */
-                        pr_emerg("kmmio: recursive probe hit on CPU %d, "
-                                        "for address 0x%08lx. Ignoring.\n",
-                                        smp_processor_id(), addr);
-                        pr_emerg("kmmio: previous hit was at 0x%08lx.\n",
-                                                ctx->addr);
+                        pr_emerg("recursive probe hit on CPU %d, for address 0x%08lx. Ignoring.\n",
+                                 smp_processor_id(), addr);
+                        pr_emerg("previous hit was at 0x%08lx.\n", ctx->addr);
                         disarm_kmmio_fault_page(faultpage);
                 }
                 goto no_kmmio_ctx;
@@ -302,7 +303,7 @@ no_kmmio:
 
 /*
  * Interrupts are disabled on entry as trap1 is an interrupt gate
- * and they remain disabled thorough out this function.
+ * and they remain disabled throughout this function.
  * This must always get called as the pair to kmmio_handler().
  */
 static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs)
@@ -316,8 +317,8 @@ static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs)
                  * something external causing them (f.e. using a debugger while
                  * mmio tracing enabled), or erroneous behaviour
                  */
-                pr_warning("kmmio: unexpected debug trap on CPU %d.\n",
-                                                        smp_processor_id());
+                pr_warning("unexpected debug trap on CPU %d.\n",
+                           smp_processor_id());
                 goto out;
         }
 
@@ -425,7 +426,7 @@ int register_kmmio_probe(struct kmmio_probe *p)
         list_add_rcu(&p->list, &kmmio_probes);
         while (size < size_lim) {
                 if (add_kmmio_fault_page(p->addr + size))
-                        pr_err("kmmio: Unable to set page fault.\n");
+                        pr_err("Unable to set page fault.\n");
                 size += PAGE_SIZE;
         }
 out:
@@ -490,7 +491,7 @@ static void remove_kmmio_fault_pages(struct rcu_head *head)
  * 2. remove_kmmio_fault_pages()
  *    Remove the pages from kmmio_page_table.
  * 3. rcu_free_kmmio_fault_pages()
- *    Actally free the kmmio_fault_page structs as with RCU.
+ *    Actually free the kmmio_fault_page structs as with RCU.
  */
 void unregister_kmmio_probe(struct kmmio_probe *p)
 {
@@ -511,7 +512,7 @@ void unregister_kmmio_probe(struct kmmio_probe *p)
 
         drelease = kmalloc(sizeof(*drelease), GFP_ATOMIC);
         if (!drelease) {
-                pr_crit("kmmio: leaking kmmio_fault_page objects.\n");
+                pr_crit("leaking kmmio_fault_page objects.\n");
                 return;
         }
         drelease->release_list = release_list;
@@ -538,10 +539,17 @@ static int
 kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)
 {
         struct die_args *arg = args;
+        unsigned long* dr6_p = (unsigned long *)ERR_PTR(arg->err);
 
-        if (val == DIE_DEBUG && (arg->err & DR_STEP))
-                if (post_kmmio_handler(arg->err, arg->regs) == 1)
+        if (val == DIE_DEBUG && (*dr6_p & DR_STEP))
+                if (post_kmmio_handler(*dr6_p, arg->regs) == 1) {
+                        /*
+                         * Reset the BS bit in dr6 (pointed by args->err) to
+                         * denote completion of processing
+                         */
+                        *dr6_p &= ~DR_STEP;
                         return NOTIFY_STOP;
+                }
 
         return NOTIFY_DONE;
 }