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

[Atsushi Kumagai]

Hello Baoquan,

Thanks for your work, I have some comments below.

>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  | 26 +++++++++-----------------
> makedumpfile.c | 29 ++++++++++++++++++++++++++++-
> makedumpfile.h |  3 +++
> 3 files changed, 40 insertions(+), 18 deletions(-)
>
>diff --git a/arch/x86_64.c b/arch/x86_64.c
>index ddf7be6..ff787cc 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 +160,13 @@ 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;
>+	info->page_offset = NUMBER(page_offset);
>
>-	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;
>-	}

These *_END_* are no longer used, it's better to remove the definitions
of them.

>+
>+	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 2713f8a..6b0c6ab 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -1985,6 +1985,7 @@ get_value_for_old_linux(void)
> 			NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) =
> 			PAGE_BUDDY_MAPCOUNT_VALUE_v2_6_39_to_latest_version;
> 	}
>+	ERRMSG("info->kernel_version=%d\n", info->kernel_version);

Is this just a debug message ?

> #ifdef __x86_64__
> 	if (NUMBER(KERNEL_IMAGE_SIZE) == NOT_FOUND_NUMBER) {
> 		if (info->kernel_version < KERNEL_VERSION(2, 6, 26))
>@@ -1992,6 +1993,26 @@ get_value_for_old_linux(void)
> 		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;
>+	}
>+

(I should have said this when you post the early kaslr patch.)
This logic is only for x86_64, I don't like to take it out to 
here(general pass) with #ifdef. Is there any necessity to write
this code here ?

> #endif
> 	if (SIZE(pageflags) == NOT_FOUND_STRUCTURE) {
> 		if (info->kernel_version >= KERNEL_VERSION(2, 6, 27))
>@@ -2249,6 +2270,9 @@ 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 +2619,9 @@ 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);
>
>@@ -3826,7 +3853,7 @@ initial(void)
> 		debug_info = TRUE;
> 	}
>
>-	info->kernel_version = get_kernel_version(info.release);
>+	info->kernel_version = get_kernel_version(info->release);

Why don't you write "info->release" in [PATCH 1/3] ?

Thanks,
Atsushi Kumagai

> 	if (info->kernel_version == FALSE) {
> 		ERRMSG("Can't get the kernel version.\n");
> 		return FALSE;
>diff --git a/makedumpfile.h b/makedumpfile.h
>index 533e5b8..0e34fae 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -1685,6 +1685,9 @@ 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
>
>
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