kcore: register vmemmap range

Benjamin Herrenschmidt <benh@kernel.crashing.org> pointed out that vmemmap
range is not included in KCORE_RAM, KCORE_VMALLOC ....

This adds KCORE_VMEMMAP if SPARSEMEM_VMEMMAP is used.  By this, vmemmap
can be readable via /proc/kcore

Because it's not vmalloc area, vread/vwrite cannot be used.  But the range
is static against the memory layout, this patch handles vmemmap area by
the same scheme with physical memory.

This patch assumes SPARSEMEM_VMEMMAP range is not in VMALLOC range.  It's
correct now.

[akpm@linux-foundation.org: fix typo]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 802de33d634102470004173d6c962d57cdca9bb6..78970e6f715c04e8eb0fd0a16a45854102820e68 100644 (file)
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -103,7 +103,7 @@ static void free_kclist_ents(struct list_head *head)
        }
 }
 /*
- * Replace all KCORE_RAM information with passed list.
+ * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list.
  */
 static void __kcore_update_ram(struct list_head *list)
 {
@@ -113,7 +113,8 @@ static void __kcore_update_ram(struct list_head *list)
        write_lock(&kclist_lock);
        if (kcore_need_update) {
                list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
-                       if (pos->type == KCORE_RAM)
+                       if (pos->type == KCORE_RAM
+                               || pos->type == KCORE_VMEMMAP)
                                list_move(&pos->list, &garbage);
                }
                list_splice_tail(list, &kclist_head);
@@ -151,6 +152,47 @@ static int kcore_update_ram(void)
 
 #else /* !CONFIG_HIGHMEM */
 
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+/* calculate vmemmap's address from given system ram pfn and register it */
+int get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+       unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
+       unsigned long nr_pages = ent->size >> PAGE_SHIFT;
+       unsigned long start, end;
+       struct kcore_list *vmm, *tmp;
+
+
+       start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
+       end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
+       end = ALIGN(end, PAGE_SIZE);
+       /* overlap check (because we have to align page */
+       list_for_each_entry(tmp, head, list) {
+               if (tmp->type != KCORE_VMEMMAP)
+                       continue;
+               if (start < tmp->addr + tmp->size)
+                       if (end > tmp->addr)
+                               end = tmp->addr;
+       }
+       if (start < end) {
+               vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
+               if (!vmm)
+                       return 0;
+               vmm->addr = start;
+               vmm->size = end - start;
+               vmm->type = KCORE_VMEMMAP;
+               list_add_tail(&vmm->list, head);
+       }
+       return 1;
+
+}
+#else
+int get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+       return 1;
+}
+
+#endif
+
 static int
 kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
 {
@@ -181,6 +223,12 @@ kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
 
        ent->type = KCORE_RAM;
        list_add_tail(&ent->list, head);
+
+       if (!get_sparsemem_vmemmap_info(ent, head)) {
+               list_del(&ent->list);
+               goto free_out;
+       }
+
        return 0;
 free_out:
        kfree(ent);

diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index bd7b840765a0327e784fd6ead4fa07bcdd13b35b..379eaed72d4b447d7e3b5098ab48e65d7bd959f9 100644 (file)
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -82,6 +82,7 @@ enum kcore_type {
        KCORE_TEXT,
        KCORE_VMALLOC,
        KCORE_RAM,
+       KCORE_VMEMMAP,
        KCORE_OTHER,
 };