[PATCH] makedumpfile: s390x: Obtain the vmalloc_start value from high_memory for s390x arch.

[Mahesh J Salgaonkar]

From: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>

Currently the vmalloc_start address for s390x is obtained by using
vmlist.addr symbol, which is not correct. The correct vmalloc_start address
can be obtained using 'high_memory' symbol. Even crash utility is depend
on high_memory symbol to get vmalloc_start address for s390x arch.

Without this patch makedumpfile fails to translate some virtual addresses to
to physical addresses on s390x.

[root at h4245043 makedumpfile]# ./makedumpfile -d 16 -x /root/dump.makedumpfile_problem/vmlinux /root/dump.makedumpfile_problem/vmcore /tmp/out.dump
The kernel version is not supported.
The created dumpfile may be incomplete.
Checking for memory holes          : [100 %] readmem: Can't convert a physical address(3d2805c1830) to offset.
readmem: type_addr: 0, addr:3d2805c1830, size:8
reset_bitmap_of_free_pages: Can't get prev list_head.

makedumpfile Failed.
[root at h4245043 makedumpfile]#

Signed-off-by: Mahesh Salgaonkar <mahesh at linux.vnet.ibm.com>
---
 arch/s390x.c   |   19 ++++++-------------
 makedumpfile.c |    3 +++
 makedumpfile.h |    5 +++++
 3 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/arch/s390x.c b/arch/s390x.c
index e7d7603..9237eaa 100644
--- a/arch/s390x.c
+++ b/arch/s390x.c
@@ -62,7 +62,7 @@
 int
 get_machdep_info_s390x(void)
 {
-	unsigned long vmlist, vmalloc_start;
+	unsigned long vmalloc_start;
 	char *term_str = getenv("TERM");
 
 	if (term_str && strcmp(term_str, "dumb") == 0)
@@ -81,19 +81,13 @@ get_machdep_info_s390x(void)
 	DEBUG_MSG("kernel_start : %lx\n", info->kernel_start);
 
 	/*
-	 * For the compatibility, makedumpfile should run without the symbol
-	 * vmlist and the offset of vm_struct.addr if they are not necessary.
+	 * Obtain the vmalloc_start address from high_memory symbol.
 	 */
-	if ((SYMBOL(vmlist) == NOT_FOUND_SYMBOL)
-	    || (OFFSET(vm_struct.addr) == NOT_FOUND_STRUCTURE)) {
+	if (SYMBOL(high_memory) == NOT_FOUND_SYMBOL) {
 		return TRUE;
 	}
-	if (!readmem(VADDR, SYMBOL(vmlist), &vmlist, sizeof(vmlist))) {
-		ERRMSG("Can't get vmlist.\n");
-		return FALSE;
-	}
-	if (!readmem(VADDR, vmlist + OFFSET(vm_struct.addr), &vmalloc_start,
-	    sizeof(vmalloc_start))) {
+	if (!readmem(VADDR, SYMBOL(high_memory), &vmalloc_start,
+			sizeof(vmalloc_start))) {
 		ERRMSG("Can't get vmalloc_start.\n");
 		return FALSE;
 	}
@@ -265,8 +259,7 @@ vaddr_to_paddr_s390x(unsigned long vaddr)
 	if (paddr != NOT_PADDR)
 		return paddr;
 
-	if ((SYMBOL(vmlist) == NOT_FOUND_SYMBOL)
-	    || (OFFSET(vm_struct.addr) == NOT_FOUND_STRUCTURE)) {
+	if (SYMBOL(high_memory) == NOT_FOUND_SYMBOL) {
 		ERRMSG("Can't get necessary information for vmalloc "
 			"translation.\n");
 		return NOT_PADDR;
diff --git a/makedumpfile.c b/makedumpfile.c
index 7b7c266..67f1a10 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -797,6 +797,7 @@ get_symbol_info(void)
 	SYMBOL_INIT(log_end, "log_end");
 	SYMBOL_INIT(max_pfn, "max_pfn");
 	SYMBOL_INIT(modules, "modules");
+	SYMBOL_INIT(high_memory, "high_memory");
 
 	if (SYMBOL(node_data) != NOT_FOUND_SYMBOL)
 		SYMBOL_ARRAY_TYPE_INIT(node_data, "node_data");
@@ -1108,6 +1109,7 @@ generate_vmcoreinfo(void)
 	WRITE_SYMBOL("log_buf_len", log_buf_len);
 	WRITE_SYMBOL("log_end", log_end);
 	WRITE_SYMBOL("max_pfn", max_pfn);
+	WRITE_SYMBOL("high_memory", high_memory);
 
 	/*
 	 * write the structure size of 1st kernel
@@ -1366,6 +1368,7 @@ read_vmcoreinfo(void)
 	READ_SYMBOL("log_buf_len", log_buf_len);
 	READ_SYMBOL("log_end", log_end);
 	READ_SYMBOL("max_pfn", max_pfn);
+	READ_SYMBOL("high_memory", high_memory);
 
 	READ_STRUCTURE_SIZE("page", page);
 	READ_STRUCTURE_SIZE("mem_section", mem_section);
diff --git a/makedumpfile.h b/makedumpfile.h
index f0e5da8..b3de521 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -974,6 +974,11 @@ struct symbol_table {
 	 */
 
 	unsigned long long	modules;
+
+	/*
+	 * vmalloc_start address on s390x arch
+	 */
+	unsigned long long	high_memory;
 };
 
 struct size_table {