[PATCH v2 1/2] makedumpfile: Adapt code to get value of phys_base

[Baoquan He]

Kernel code only exports virtual address of phys_base now and it's helpless
for Crash and Makedumpfile. Below patch which changes code to export value
of phys_base has been posted to upstream. So adapt code to get it.

kexec: Change to export the value of phys_base instead of symbol address
marc.info/?l=linux-kernel&m=147856863629624&w=2

Signed-off-by: Baoquan He <bhe at redhat.com>
---
v1->v2:
    Patch v1 is not compatible with the old kernel. Change code in
    get_phys_base_x86_64 and vtop4_x86_64 to avoid that according to
    Atsushi's suggestion. 

 arch/x86_64.c  | 12 +++++-------
 makedumpfile.c |  5 ++---
 makedumpfile.h |  2 +-
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/arch/x86_64.c b/arch/x86_64.c
index 3ef33ae..010ea10 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -62,6 +62,10 @@ get_phys_base_x86_64(void)
 	 * Get the relocatable offset
 	 */
 	info->phys_base = 0; /* default/traditional */
+	if (NUMBER(phys_base) != NOT_FOUND_NUMBER) {
+		info->phys_base = NUMBER(phys_base);
+		return TRUE;
+	}
 
 	for (i = 0; get_pt_load(i, &phys_start, NULL, &virt_start, NULL); i++) {
 		if (virt_start >= __START_KERNEL_map) {
@@ -187,12 +191,6 @@ vtop4_x86_64(unsigned long vaddr)
 {
 	unsigned long page_dir, pml4, pgd_paddr, pgd_pte, pmd_paddr, pmd_pte;
 	unsigned long pte_paddr, pte;
-	unsigned long phys_base;
-
-	if (SYMBOL(phys_base) != NOT_FOUND_SYMBOL)
-		phys_base = info->phys_base;
-	else
-		phys_base = 0;
 
 	if (SYMBOL(init_level4_pgt) == NOT_FOUND_SYMBOL) {
 		ERRMSG("Can't get the symbol of init_level4_pgt.\n");
@@ -202,7 +200,7 @@ vtop4_x86_64(unsigned long vaddr)
 	/*
 	 * Get PGD.
 	 */
-	page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map + phys_base;
+	page_dir = SYMBOL(init_level4_pgt) - __START_KERNEL_map + info->phys_base;
 	page_dir += pml4_index(vaddr) * sizeof(unsigned long);
 	if (!readmem(PADDR, page_dir, &pml4, sizeof pml4)) {
 		ERRMSG("Can't get pml4 (page_dir:%lx).\n", page_dir);
diff --git a/makedumpfile.c b/makedumpfile.c
index b916dfb..a3f711e 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -1507,7 +1507,6 @@ get_symbol_info(void)
 	SYMBOL_INIT(init_level4_pgt, "init_level4_pgt");
 	SYMBOL_INIT(vmlist, "vmlist");
 	SYMBOL_INIT(vmap_area_list, "vmap_area_list");
-	SYMBOL_INIT(phys_base, "phys_base");
 	SYMBOL_INIT(node_online_map, "node_online_map");
 	SYMBOL_INIT(node_states, "node_states");
 	SYMBOL_INIT(node_memblk, "node_memblk");
@@ -2134,7 +2133,6 @@ write_vmcoreinfo_data(void)
 	WRITE_SYMBOL("init_level4_pgt", init_level4_pgt);
 	WRITE_SYMBOL("vmlist", vmlist);
 	WRITE_SYMBOL("vmap_area_list", vmap_area_list);
-	WRITE_SYMBOL("phys_base", phys_base);
 	WRITE_SYMBOL("node_online_map", node_online_map);
 	WRITE_SYMBOL("node_states", node_states);
 	WRITE_SYMBOL("node_data", node_data);
@@ -2261,6 +2259,7 @@ write_vmcoreinfo_data(void)
 
 	WRITE_NUMBER("PAGE_BUDDY_MAPCOUNT_VALUE", PAGE_BUDDY_MAPCOUNT_VALUE);
 	WRITE_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE);
+	WRITE_NUMBER("phys_base", phys_base);
 
 	WRITE_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR);
 
@@ -2488,7 +2487,6 @@ read_vmcoreinfo(void)
 	READ_SYMBOL("init_level4_pgt", init_level4_pgt);
 	READ_SYMBOL("vmlist", vmlist);
 	READ_SYMBOL("vmap_area_list", vmap_area_list);
-	READ_SYMBOL("phys_base", phys_base);
 	READ_SYMBOL("node_online_map", node_online_map);
 	READ_SYMBOL("node_states", node_states);
 	READ_SYMBOL("node_data", node_data);
@@ -2609,6 +2607,7 @@ read_vmcoreinfo(void)
 
 	READ_NUMBER("PAGE_BUDDY_MAPCOUNT_VALUE", PAGE_BUDDY_MAPCOUNT_VALUE);
 	READ_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE);
+	READ_NUMBER("phys_base", phys_base);
 
 	READ_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR);
 
diff --git a/makedumpfile.h b/makedumpfile.h
index 338c651..422b6be 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -1394,7 +1394,6 @@ struct symbol_table {
 	unsigned long long	init_level4_pgt;
 	unsigned long long	vmlist;
 	unsigned long long	vmap_area_list;
-	unsigned long long	phys_base;
 	unsigned long long	node_online_map;
 	unsigned long long	node_states;
 	unsigned long long	node_memblk;
@@ -1718,6 +1717,7 @@ struct number_table {
 	long	SECTION_SIZE_BITS;
 	long	MAX_PHYSMEM_BITS;
 	long    HUGETLB_PAGE_DTOR;
+	long	phys_base;
 };
 
 struct srcfile_table {
-- 
2.5.5