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Subject[PATCH 7/8][mmotm] kcore register vmemmap range
This new patch is for enhancement.
=
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

---
fs/proc/kcore.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++--
include/linux/proc_fs.h | 1
2 files changed, 51 insertions(+), 2 deletions(-)

Index: mmotm-2.6.31-Aug27/fs/proc/kcore.c
===================================================================
--- mmotm-2.6.31-Aug27.orig/fs/proc/kcore.c
+++ mmotm-2.6.31-Aug27/fs/proc/kcore.c
@@ -103,7 +103,7 @@ static void free_kclist_ents(struct list
}
}
/*
- * 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 li
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_vmemamp_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, un

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);
Index: mmotm-2.6.31-Aug27/include/linux/proc_fs.h
===================================================================
--- mmotm-2.6.31-Aug27.orig/include/linux/proc_fs.h
+++ mmotm-2.6.31-Aug27/include/linux/proc_fs.h
@@ -82,6 +82,7 @@ enum kcore_type {
KCORE_TEXT,
KCORE_VMALLOC,
KCORE_RAM,
+ KCORE_VMEMMAP,
KCORE_OTHER,
};



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