3 files changed, 42 insertions, 7 deletions

diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 58176b56354e..294ed4392a0e 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -14,6 +14,7 @@
 #define pr_fmt(fmt) "AGP: " fmt
 
 #include <linux/kernel.h>
+#include <linux/kcore.h>
 #include <linux/types.h>
 #include <linux/init.h>
 #include <linux/memblock.h>
@@ -57,7 +58,7 @@ int fallback_aper_force __initdata;
 
 int fix_aperture __initdata = 1;
 
-#ifdef CONFIG_PROC_VMCORE
+#if defined(CONFIG_PROC_VMCORE) || defined(CONFIG_PROC_KCORE)
 /*
  * If the first kernel maps the aperture over e820 RAM, the kdump kernel will
  * use the same range because it will remain configured in the northbridge.
@@ -66,20 +67,25 @@ int fix_aperture __initdata = 1;
  */
 static unsigned long aperture_pfn_start, aperture_page_count;
 
-static int gart_oldmem_pfn_is_ram(unsigned long pfn)
+static int gart_mem_pfn_is_ram(unsigned long pfn)
 {
         return likely((pfn < aperture_pfn_start) ||
                       (pfn >= aperture_pfn_start + aperture_page_count));
 }
 
-static void exclude_from_vmcore(u64 aper_base, u32 aper_order)
+static void __init exclude_from_core(u64 aper_base, u32 aper_order)
 {
         aperture_pfn_start = aper_base >> PAGE_SHIFT;
         aperture_page_count = (32 * 1024 * 1024) << aper_order >> PAGE_SHIFT;
-        WARN_ON(register_oldmem_pfn_is_ram(&gart_oldmem_pfn_is_ram));
+#ifdef CONFIG_PROC_VMCORE
+        WARN_ON(register_oldmem_pfn_is_ram(&gart_mem_pfn_is_ram));
+#endif
+#ifdef CONFIG_PROC_KCORE
+        WARN_ON(register_mem_pfn_is_ram(&gart_mem_pfn_is_ram));
+#endif
 }
 #else
-static void exclude_from_vmcore(u64 aper_base, u32 aper_order)
+static void exclude_from_core(u64 aper_base, u32 aper_order)
 {
 }
 #endif
@@ -474,7 +480,7 @@ out:
                          * may have allocated the range over its e820 RAM
                          * and fixed up the northbridge
                          */
-                        exclude_from_vmcore(last_aper_base, last_aper_order);
+                        exclude_from_core(last_aper_base, last_aper_order);
 
                         return 1;
                 }
@@ -520,7 +526,7 @@ out:
          * overlap with the first kernel's memory. We can't access the
          * range through vmcore even though it should be part of the dump.
          */
-        exclude_from_vmcore(aper_alloc, aper_order);
+        exclude_from_core(aper_alloc, aper_order);
 
         /* Fix up the north bridges */
         for (i = 0; i < amd_nb_bus_dev_ranges[i].dev_limit; i++) {
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index bbcc185062bb..d29d869abec1 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -54,6 +54,28 @@ static LIST_HEAD(kclist_head);
 static DECLARE_RWSEM(kclist_lock);
 static int kcore_need_update = 1;
 
+/*
+ * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
+ * Same as oldmem_pfn_is_ram in vmcore
+ */
+static int (*mem_pfn_is_ram)(unsigned long pfn);
+
+int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn))
+{
+        if (mem_pfn_is_ram)
+                return -EBUSY;
+        mem_pfn_is_ram = fn;
+        return 0;
+}
+
+static int pfn_is_ram(unsigned long pfn)
+{
+        if (mem_pfn_is_ram)
+                return mem_pfn_is_ram(pfn);
+        else
+                return 1;
+}
+
 /* This doesn't grab kclist_lock, so it should only be used at init time. */
 void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
                        int type)
@@ -465,6 +487,11 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
                                 goto out;
                         }
                         m = NULL;       /* skip the list anchor */
+                } else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {
+                        if (clear_user(buffer, tsz)) {
+                                ret = -EFAULT;
+                                goto out;
+                        }
                 } else if (m->type == KCORE_VMALLOC) {
                         vread(buf, (char *)start, tsz);
                         /* we have to zero-fill user buffer even if no read */
diff --git a/include/linux/kcore.h b/include/linux/kcore.h
index 8c3f8c14eeaa..c843f4a9c512 100644
--- a/include/linux/kcore.h
+++ b/include/linux/kcore.h
@@ -44,6 +44,8 @@ void kclist_add_remap(struct kcore_list *m, void *addr, void *vaddr, size_t sz)
         m->vaddr = (unsigned long)vaddr;
         kclist_add(m, addr, sz, KCORE_REMAP);
 }
+
+extern int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn));
 #else
 static inline
 void kclist_add(struct kcore_list *new, void *addr, size_t size, int type)