[PATCH v2 3/3] makedumpfile: Add support for MM randomization

[Baoquan He]

In kernel patchset "x86/mm: memory area address KASLR", PAGE_OFFSET,
VMALLOC_START and VMEMMAP_START are all randomized. Please check below
link:
	https://lwn.net/Articles/692289/

And these need be exported into vmcoreinfo and tell makedumpfile. In
this patch get and handle them to support MM randomization.

Signed-off-by: Baoquan He <bhe at redhat.com>
---
 arch/x86_64.c  | 51 ++++++++++++++++++++++++++++++++++-----------------
 makedumpfile.c | 15 +++++++--------
 makedumpfile.h |  7 +++----
 3 files changed, 44 insertions(+), 29 deletions(-)

diff --git a/arch/x86_64.c b/arch/x86_64.c
index ddf7be6..1fd193f 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -146,8 +146,9 @@ get_machdep_info_x86_64(void)
 	return TRUE;
 }
 
-int
-get_versiondep_info_x86_64(void)
+#define VMALLOC_SIZE            (0x200000000000)
+#define VMEMMAP_SIZE            (0x10000000000)
+int get_versiondep_info_x86_64(void)
 {
 	/*
 	 * On linux-2.6.26, MAX_PHYSMEM_BITS is changed to 44 from 40.
@@ -159,22 +160,38 @@ get_versiondep_info_x86_64(void)
 	else
 		info->max_physmem_bits  = _MAX_PHYSMEM_BITS_2_6_31;
 
-	if (info->kernel_version < KERNEL_VERSION(2, 6, 27))
-		info->page_offset = __PAGE_OFFSET_ORIG;
-	else
-		info->page_offset = __PAGE_OFFSET_2_6_27;
-
-	if (info->kernel_version < KERNEL_VERSION(2, 6, 31)) {
-		info->vmalloc_start = VMALLOC_START_ORIG;
-		info->vmalloc_end   = VMALLOC_END_ORIG;
-		info->vmemmap_start = VMEMMAP_START_ORIG;
-		info->vmemmap_end   = VMEMMAP_END_ORIG;
-	} else {
-		info->vmalloc_start = VMALLOC_START_2_6_31;
-		info->vmalloc_end   = VMALLOC_END_2_6_31;
-		info->vmemmap_start = VMEMMAP_START_2_6_31;
-		info->vmemmap_end   = VMEMMAP_END_2_6_31;
+	if (NUMBER(KERNEL_IMAGE_SIZE) == NOT_FOUND_NUMBER) {
+		if (info->kernel_version < KERNEL_VERSION(2, 6, 26))
+			NUMBER(KERNEL_IMAGE_SIZE) = KERNEL_IMAGE_SIZE_ORIG;
+		else
+			NUMBER(KERNEL_IMAGE_SIZE) = KERNEL_IMAGE_SIZE_2_6_26;
+	}
+	if (NUMBER(page_offset) == NOT_FOUND_NUMBER) {
+		if (info->kernel_version < KERNEL_VERSION(2, 6, 27))
+			NUMBER(page_offset) = __PAGE_OFFSET_ORIG;
+		else
+			NUMBER(page_offset) = __PAGE_OFFSET_2_6_27;
 	}
+	if (NUMBER(vmalloc_start) == NOT_FOUND_NUMBER) {
+		if (info->kernel_version < KERNEL_VERSION(2, 6, 31)) {
+			NUMBER(vmalloc_start) = VMALLOC_START_ORIG;
+		} else {
+			NUMBER(vmalloc_start) = VMALLOC_START_2_6_31;
+		}
+	}
+	if (NUMBER(vmemmap_start) == NOT_FOUND_NUMBER) {
+		if (info->kernel_version < KERNEL_VERSION(2, 6, 31))
+			NUMBER(vmemmap_start) = VMEMMAP_START_ORIG;
+		else
+			NUMBER(vmemmap_start) = VMEMMAP_START_2_6_31;
+	}
+
+	info->page_offset = NUMBER(page_offset);
+
+	info->vmalloc_start = NUMBER(vmalloc_start);
+	info->vmalloc_end   = info->vmalloc_start + VMALLOC_SIZE - 1;
+	info->vmemmap_start = NUMBER(vmemmap_start);
+	info->vmemmap_end   = info->vmemmap_start + VMEMMAP_SIZE - 1;
 
 	return TRUE;
 }
diff --git a/makedumpfile.c b/makedumpfile.c
index e132550..bf990f1 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -1985,14 +1985,7 @@ get_value_for_old_linux(void)
 			NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) =
 			PAGE_BUDDY_MAPCOUNT_VALUE_v2_6_39_to_latest_version;
 	}
-#ifdef __x86_64__
-	if (NUMBER(KERNEL_IMAGE_SIZE) == NOT_FOUND_NUMBER) {
-		if (info->kernel_version < KERNEL_VERSION(2, 6, 26))
-			NUMBER(KERNEL_IMAGE_SIZE) = KERNEL_IMAGE_SIZE_ORIG;
-		else
-			NUMBER(KERNEL_IMAGE_SIZE) = KERNEL_IMAGE_SIZE_2_6_26;
-	}
-#endif
+
 	if (SIZE(pageflags) == NOT_FOUND_STRUCTURE) {
 		if (info->kernel_version >= KERNEL_VERSION(2, 6, 27))
 			SIZE(pageflags) =
@@ -2249,6 +2242,9 @@ write_vmcoreinfo_data(void)
 
 	WRITE_NUMBER("PAGE_BUDDY_MAPCOUNT_VALUE", PAGE_BUDDY_MAPCOUNT_VALUE);
 	WRITE_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE);
+	WRITE_NUMBER("PAGE_OFFSET", page_offset);
+	WRITE_NUMBER("VMALLOC_START", vmalloc_start);
+	WRITE_NUMBER("VMEMMAP_START", vmemmap_start);
 
 	WRITE_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR);
 
@@ -2595,6 +2591,9 @@ read_vmcoreinfo(void)
 
 	READ_NUMBER("PAGE_BUDDY_MAPCOUNT_VALUE", PAGE_BUDDY_MAPCOUNT_VALUE);
 	READ_NUMBER("KERNEL_IMAGE_SIZE", KERNEL_IMAGE_SIZE);
+	READ_NUMBER("PAGE_OFFSET", page_offset);
+	READ_NUMBER("VMALLOC_START", vmalloc_start);
+	READ_NUMBER("VMEMMAP_START", vmemmap_start);
 
 	READ_NUMBER("HUGETLB_PAGE_DTOR", HUGETLB_PAGE_DTOR);
 
diff --git a/makedumpfile.h b/makedumpfile.h
index 1814139..17f71a3 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -564,13 +564,9 @@ int get_va_bits_arm64(void);
 
 #define VMALLOC_START_ORIG	(0xffffc20000000000) /* 2.6.30, or former */
 #define VMALLOC_START_2_6_31	(0xffffc90000000000) /* 2.6.31, or later  */
-#define VMALLOC_END_ORIG	(0xffffe1ffffffffff) /* 2.6.30, or former */
-#define VMALLOC_END_2_6_31	(0xffffe8ffffffffff) /* 2.6.31, or later  */
 
 #define VMEMMAP_START_ORIG	(0xffffe20000000000) /* 2.6.30, or former */
 #define VMEMMAP_START_2_6_31	(0xffffea0000000000) /* 2.6.31, or later  */
-#define VMEMMAP_END_ORIG	(0xffffe2ffffffffff) /* 2.6.30, or former */
-#define VMEMMAP_END_2_6_31	(0xffffeaffffffffff) /* 2.6.31, or later  */
 
 #define __START_KERNEL_map	(0xffffffff80000000)
 #define KERNEL_IMAGE_SIZE_ORIG		(0x0000000008000000) /* 2.6.25, or former */
@@ -1685,6 +1681,9 @@ struct number_table {
 
 	long	PAGE_BUDDY_MAPCOUNT_VALUE;
 	long	KERNEL_IMAGE_SIZE;
+	long	page_offset;
+	long	vmalloc_start;
+	long	vmemmap_start;
 	long	SECTION_SIZE_BITS;
 	long	MAX_PHYSMEM_BITS;
 	long    HUGETLB_PAGE_DTOR;
-- 
2.5.5