We need to keep track of the backing pages that get allocated by
vmemmap_populate() so that when we use kdump, the dump-capture kernel can
find these pages in memory.
We use a linked list of structures that contain the physical address of the
backing page and corresponding virtual address to track the backing pages.
And we use a simple spinlock to protect the vmemmap_list.
Signed-off-by: Mark Nelson <ma...@au1.ibm.com>
---
arch/powerpc/include/asm/pgalloc-64.h | 7 +++++++
arch/powerpc/mm/init_64.c | 27 +++++++++++++++++++++++++++
2 files changed, 34 insertions(+)
Index: upstream/arch/powerpc/include/asm/pgalloc-64.h
===================================================================
--- upstream.orig/arch/powerpc/include/asm/pgalloc-64.h
+++ upstream/arch/powerpc/include/asm/pgalloc-64.h
@@ -10,6 +10,13 @@
#include <linux/slab.h>
#include <linux/cpumask.h>
#include <linux/percpu.h>
+#include <linux/list.h>
+
+struct vmemmap_backing {
+ unsigned long phys;
+ unsigned long virt_addr;
+ struct list_head list;
+};
/*
* Functions that deal with pagetables that could be at any level of
Index: upstream/arch/powerpc/mm/init_64.c
===================================================================
--- upstream.orig/arch/powerpc/mm/init_64.c
+++ upstream/arch/powerpc/mm/init_64.c
@@ -42,6 +42,7 @@
#include <linux/poison.h>
#include <linux/lmb.h>
#include <linux/hugetlb.h>
+#include <linux/list.h>
#include <asm/pgalloc.h>
#include <asm/page.h>
@@ -251,6 +252,30 @@ static void __meminit vmemmap_create_map
}
#endif /* CONFIG_PPC_BOOK3E */
+LIST_HEAD(vmemmap_list);
+DEFINE_SPINLOCK(vmemmap_list_lock);
+
+static __meminit void vmemmap_list_populate(unsigned long phys,
+ unsigned long start,
+ int node)
+{
+ struct vmemmap_backing *vmem_back;
+
+ vmem_back = vmemmap_alloc_block(sizeof(struct vmemmap_backing), node);
+ if (unlikely(!vmem_back)) {
+ WARN_ON(1);
+ return;
+ }
+
+ vmem_back->phys = phys;
+ vmem_back->virt_addr = start;
+ INIT_LIST_HEAD(&vmem_back->list);
+
+ spin_lock(&vmemmap_list_lock);
+ list_add(&vmem_back->list, &vmemmap_list);
+ spin_unlock(&vmemmap_list_lock);
+}
+
int __meminit vmemmap_populate(struct page *start_page,
unsigned long nr_pages, int node)
{
@@ -275,6 +300,8 @@ int __meminit vmemmap_populate(struct pa
if (!p)
return -ENOMEM;
+ vmemmap_list_populate(__pa(p), start, node);
+
pr_debug(" * %016lx..%016lx allocated at %p\n",
start, start + page_size, p);
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