Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 kdump update from Ingo Molnar: "Add the AMD SME mask to the vmcoreinfo, and also document our vmcoreinfo fields" * 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kdump: Document kernel data exported in the vmcoreinfo note x86/kdump: Export the SME mask to vmcoreinfo
This commit is contained in:
Linus Torvalds
Коммит
d2cb698f68
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@ -0,0 +1,495 @@
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================================================================
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VMCOREINFO
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|
================================================================
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|
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||||||
|
===========
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|
What is it?
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||||||
|
===========
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||||||
|
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||||||
|
VMCOREINFO is a special ELF note section. It contains various
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|
information from the kernel like structure size, page size, symbol
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|
values, field offsets, etc. These data are packed into an ELF note
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|
section and used by user-space tools like crash and makedumpfile to
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|
analyze a kernel's memory layout.
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|
|
||||||
|
================
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||||||
|
Common variables
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||||||
|
================
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|
|
||||||
|
init_uts_ns.name.release
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||||||
|
------------------------
|
||||||
|
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||||||
|
The version of the Linux kernel. Used to find the corresponding source
|
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|
code from which the kernel has been built. For example, crash uses it to
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|
find the corresponding vmlinux in order to process vmcore.
|
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|
|
||||||
|
PAGE_SIZE
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||||||
|
---------
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|
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|
The size of a page. It is the smallest unit of data used by the memory
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|
management facilities. It is usually 4096 bytes of size and a page is
|
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|
aligned on 4096 bytes. Used for computing page addresses.
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||||||
|
|
||||||
|
init_uts_ns
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||||||
|
-----------
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||||||
|
|
||||||
|
The UTS namespace which is used to isolate two specific elements of the
|
||||||
|
system that relate to the uname(2) system call. It is named after the
|
||||||
|
data structure used to store information returned by the uname(2) system
|
||||||
|
call.
|
||||||
|
|
||||||
|
User-space tools can get the kernel name, host name, kernel release
|
||||||
|
number, kernel version, architecture name and OS type from it.
|
||||||
|
|
||||||
|
node_online_map
|
||||||
|
---------------
|
||||||
|
|
||||||
|
An array node_states[N_ONLINE] which represents the set of online nodes
|
||||||
|
in a system, one bit position per node number. Used to keep track of
|
||||||
|
which nodes are in the system and online.
|
||||||
|
|
||||||
|
swapper_pg_dir
|
||||||
|
-------------
|
||||||
|
|
||||||
|
The global page directory pointer of the kernel. Used to translate
|
||||||
|
virtual to physical addresses.
|
||||||
|
|
||||||
|
_stext
|
||||||
|
------
|
||||||
|
|
||||||
|
Defines the beginning of the text section. In general, _stext indicates
|
||||||
|
the kernel start address. Used to convert a virtual address from the
|
||||||
|
direct kernel map to a physical address.
|
||||||
|
|
||||||
|
vmap_area_list
|
||||||
|
--------------
|
||||||
|
|
||||||
|
Stores the virtual area list. makedumpfile gets the vmalloc start value
|
||||||
|
from this variable and its value is necessary for vmalloc translation.
|
||||||
|
|
||||||
|
mem_map
|
||||||
|
-------
|
||||||
|
|
||||||
|
Physical addresses are translated to struct pages by treating them as
|
||||||
|
an index into the mem_map array. Right-shifting a physical address
|
||||||
|
PAGE_SHIFT bits converts it into a page frame number which is an index
|
||||||
|
into that mem_map array.
|
||||||
|
|
||||||
|
Used to map an address to the corresponding struct page.
|
||||||
|
|
||||||
|
contig_page_data
|
||||||
|
----------------
|
||||||
|
|
||||||
|
Makedumpfile gets the pglist_data structure from this symbol, which is
|
||||||
|
used to describe the memory layout.
|
||||||
|
|
||||||
|
User-space tools use this to exclude free pages when dumping memory.
|
||||||
|
|
||||||
|
mem_section|(mem_section, NR_SECTION_ROOTS)|(mem_section, section_mem_map)
|
||||||
|
--------------------------------------------------------------------------
|
||||||
|
|
||||||
|
The address of the mem_section array, its length, structure size, and
|
||||||
|
the section_mem_map offset.
|
||||||
|
|
||||||
|
It exists in the sparse memory mapping model, and it is also somewhat
|
||||||
|
similar to the mem_map variable, both of them are used to translate an
|
||||||
|
address.
|
||||||
|
|
||||||
|
page
|
||||||
|
----
|
||||||
|
|
||||||
|
The size of a page structure. struct page is an important data structure
|
||||||
|
and it is widely used to compute contiguous memory.
|
||||||
|
|
||||||
|
pglist_data
|
||||||
|
-----------
|
||||||
|
|
||||||
|
The size of a pglist_data structure. This value is used to check if the
|
||||||
|
pglist_data structure is valid. It is also used for checking the memory
|
||||||
|
type.
|
||||||
|
|
||||||
|
zone
|
||||||
|
----
|
||||||
|
|
||||||
|
The size of a zone structure. This value is used to check if the zone
|
||||||
|
structure has been found. It is also used for excluding free pages.
|
||||||
|
|
||||||
|
free_area
|
||||||
|
---------
|
||||||
|
|
||||||
|
The size of a free_area structure. It indicates whether the free_area
|
||||||
|
structure is valid or not. Useful when excluding free pages.
|
||||||
|
|
||||||
|
list_head
|
||||||
|
---------
|
||||||
|
|
||||||
|
The size of a list_head structure. Used when iterating lists in a
|
||||||
|
post-mortem analysis session.
|
||||||
|
|
||||||
|
nodemask_t
|
||||||
|
----------
|
||||||
|
|
||||||
|
The size of a nodemask_t type. Used to compute the number of online
|
||||||
|
nodes.
|
||||||
|
|
||||||
|
(page, flags|_refcount|mapping|lru|_mapcount|private|compound_dtor|
|
||||||
|
compound_order|compound_head)
|
||||||
|
-------------------------------------------------------------------
|
||||||
|
|
||||||
|
User-space tools compute their values based on the offset of these
|
||||||
|
variables. The variables are used when excluding unnecessary pages.
|
||||||
|
|
||||||
|
(pglist_data, node_zones|nr_zones|node_mem_map|node_start_pfn|node_
|
||||||
|
spanned_pages|node_id)
|
||||||
|
-------------------------------------------------------------------
|
||||||
|
|
||||||
|
On NUMA machines, each NUMA node has a pg_data_t to describe its memory
|
||||||
|
layout. On UMA machines there is a single pglist_data which describes the
|
||||||
|
whole memory.
|
||||||
|
|
||||||
|
These values are used to check the memory type and to compute the
|
||||||
|
virtual address for memory map.
|
||||||
|
|
||||||
|
(zone, free_area|vm_stat|spanned_pages)
|
||||||
|
---------------------------------------
|
||||||
|
|
||||||
|
Each node is divided into a number of blocks called zones which
|
||||||
|
represent ranges within memory. A zone is described by a structure zone.
|
||||||
|
|
||||||
|
User-space tools compute required values based on the offset of these
|
||||||
|
variables.
|
||||||
|
|
||||||
|
(free_area, free_list)
|
||||||
|
----------------------
|
||||||
|
|
||||||
|
Offset of the free_list's member. This value is used to compute the number
|
||||||
|
of free pages.
|
||||||
|
|
||||||
|
Each zone has a free_area structure array called free_area[MAX_ORDER].
|
||||||
|
The free_list represents a linked list of free page blocks.
|
||||||
|
|
||||||
|
(list_head, next|prev)
|
||||||
|
----------------------
|
||||||
|
|
||||||
|
Offsets of the list_head's members. list_head is used to define a
|
||||||
|
circular linked list. User-space tools need these in order to traverse
|
||||||
|
lists.
|
||||||
|
|
||||||
|
(vmap_area, va_start|list)
|
||||||
|
--------------------------
|
||||||
|
|
||||||
|
Offsets of the vmap_area's members. They carry vmalloc-specific
|
||||||
|
information. Makedumpfile gets the start address of the vmalloc region
|
||||||
|
from this.
|
||||||
|
|
||||||
|
(zone.free_area, MAX_ORDER)
|
||||||
|
---------------------------
|
||||||
|
|
||||||
|
Free areas descriptor. User-space tools use this value to iterate the
|
||||||
|
free_area ranges. MAX_ORDER is used by the zone buddy allocator.
|
||||||
|
|
||||||
|
log_first_idx
|
||||||
|
-------------
|
||||||
|
|
||||||
|
Index of the first record stored in the buffer log_buf. Used by
|
||||||
|
user-space tools to read the strings in the log_buf.
|
||||||
|
|
||||||
|
log_buf
|
||||||
|
-------
|
||||||
|
|
||||||
|
Console output is written to the ring buffer log_buf at index
|
||||||
|
log_first_idx. Used to get the kernel log.
|
||||||
|
|
||||||
|
log_buf_len
|
||||||
|
-----------
|
||||||
|
|
||||||
|
log_buf's length.
|
||||||
|
|
||||||
|
clear_idx
|
||||||
|
---------
|
||||||
|
|
||||||
|
The index that the next printk() record to read after the last clear
|
||||||
|
command. It indicates the first record after the last SYSLOG_ACTION
|
||||||
|
_CLEAR, like issued by 'dmesg -c'. Used by user-space tools to dump
|
||||||
|
the dmesg log.
|
||||||
|
|
||||||
|
log_next_idx
|
||||||
|
------------
|
||||||
|
|
||||||
|
The index of the next record to store in the buffer log_buf. Used to
|
||||||
|
compute the index of the current buffer position.
|
||||||
|
|
||||||
|
printk_log
|
||||||
|
----------
|
||||||
|
|
||||||
|
The size of a structure printk_log. Used to compute the size of
|
||||||
|
messages, and extract dmesg log. It encapsulates header information for
|
||||||
|
log_buf, such as timestamp, syslog level, etc.
|
||||||
|
|
||||||
|
(printk_log, ts_nsec|len|text_len|dict_len)
|
||||||
|
-------------------------------------------
|
||||||
|
|
||||||
|
It represents field offsets in struct printk_log. User space tools
|
||||||
|
parse it and check whether the values of printk_log's members have been
|
||||||
|
changed.
|
||||||
|
|
||||||
|
(free_area.free_list, MIGRATE_TYPES)
|
||||||
|
------------------------------------
|
||||||
|
|
||||||
|
The number of migrate types for pages. The free_list is described by the
|
||||||
|
array. Used by tools to compute the number of free pages.
|
||||||
|
|
||||||
|
NR_FREE_PAGES
|
||||||
|
-------------
|
||||||
|
|
||||||
|
On linux-2.6.21 or later, the number of free pages is in
|
||||||
|
vm_stat[NR_FREE_PAGES]. Used to get the number of free pages.
|
||||||
|
|
||||||
|
PG_lru|PG_private|PG_swapcache|PG_swapbacked|PG_slab|PG_hwpoision
|
||||||
|
|PG_head_mask|PAGE_BUDDY_MAPCOUNT_VALUE(~PG_buddy)
|
||||||
|
|PAGE_OFFLINE_MAPCOUNT_VALUE(~PG_offline)
|
||||||
|
-----------------------------------------------------------------
|
||||||
|
|
||||||
|
Page attributes. These flags are used to filter various unnecessary for
|
||||||
|
dumping pages.
|
||||||
|
|
||||||
|
HUGETLB_PAGE_DTOR
|
||||||
|
-----------------
|
||||||
|
|
||||||
|
The HUGETLB_PAGE_DTOR flag denotes hugetlbfs pages. Makedumpfile
|
||||||
|
excludes these pages.
|
||||||
|
|
||||||
|
======
|
||||||
|
x86_64
|
||||||
|
======
|
||||||
|
|
||||||
|
phys_base
|
||||||
|
---------
|
||||||
|
|
||||||
|
Used to convert the virtual address of an exported kernel symbol to its
|
||||||
|
corresponding physical address.
|
||||||
|
|
||||||
|
init_top_pgt
|
||||||
|
------------
|
||||||
|
|
||||||
|
Used to walk through the whole page table and convert virtual addresses
|
||||||
|
to physical addresses. The init_top_pgt is somewhat similar to
|
||||||
|
swapper_pg_dir, but it is only used in x86_64.
|
||||||
|
|
||||||
|
pgtable_l5_enabled
|
||||||
|
------------------
|
||||||
|
|
||||||
|
User-space tools need to know whether the crash kernel was in 5-level
|
||||||
|
paging mode.
|
||||||
|
|
||||||
|
node_data
|
||||||
|
---------
|
||||||
|
|
||||||
|
This is a struct pglist_data array and stores all NUMA nodes
|
||||||
|
information. Makedumpfile gets the pglist_data structure from it.
|
||||||
|
|
||||||
|
(node_data, MAX_NUMNODES)
|
||||||
|
-------------------------
|
||||||
|
|
||||||
|
The maximum number of nodes in system.
|
||||||
|
|
||||||
|
KERNELOFFSET
|
||||||
|
------------
|
||||||
|
|
||||||
|
The kernel randomization offset. Used to compute the page offset. If
|
||||||
|
KASLR is disabled, this value is zero.
|
||||||
|
|
||||||
|
KERNEL_IMAGE_SIZE
|
||||||
|
-----------------
|
||||||
|
|
||||||
|
Currently unused by Makedumpfile. Used to compute the module virtual
|
||||||
|
address by Crash.
|
||||||
|
|
||||||
|
sme_mask
|
||||||
|
--------
|
||||||
|
|
||||||
|
AMD-specific with SME support: it indicates the secure memory encryption
|
||||||
|
mask. Makedumpfile tools need to know whether the crash kernel was
|
||||||
|
encrypted. If SME is enabled in the first kernel, the crash kernel's
|
||||||
|
page table entries (pgd/pud/pmd/pte) contain the memory encryption
|
||||||
|
mask. This is used to remove the SME mask and obtain the true physical
|
||||||
|
address.
|
||||||
|
|
||||||
|
Currently, sme_mask stores the value of the C-bit position. If needed,
|
||||||
|
additional SME-relevant info can be placed in that variable.
|
||||||
|
|
||||||
|
For example:
|
||||||
|
[ misc ][ enc bit ][ other misc SME info ]
|
||||||
|
0000_0000_0000_0000_1000_0000_0000_0000_0000_0000_..._0000
|
||||||
|
63 59 55 51 47 43 39 35 31 27 ... 3
|
||||||
|
|
||||||
|
======
|
||||||
|
x86_32
|
||||||
|
======
|
||||||
|
|
||||||
|
X86_PAE
|
||||||
|
-------
|
||||||
|
|
||||||
|
Denotes whether physical address extensions are enabled. It has the cost
|
||||||
|
of a higher page table lookup overhead, and also consumes more page
|
||||||
|
table space per process. Used to check whether PAE was enabled in the
|
||||||
|
crash kernel when converting virtual addresses to physical addresses.
|
||||||
|
|
||||||
|
====
|
||||||
|
ia64
|
||||||
|
====
|
||||||
|
|
||||||
|
pgdat_list|(pgdat_list, MAX_NUMNODES)
|
||||||
|
-------------------------------------
|
||||||
|
|
||||||
|
pg_data_t array storing all NUMA nodes information. MAX_NUMNODES
|
||||||
|
indicates the number of the nodes.
|
||||||
|
|
||||||
|
node_memblk|(node_memblk, NR_NODE_MEMBLKS)
|
||||||
|
------------------------------------------
|
||||||
|
|
||||||
|
List of node memory chunks. Filled when parsing the SRAT table to obtain
|
||||||
|
information about memory nodes. NR_NODE_MEMBLKS indicates the number of
|
||||||
|
node memory chunks.
|
||||||
|
|
||||||
|
These values are used to compute the number of nodes the crashed kernel used.
|
||||||
|
|
||||||
|
node_memblk_s|(node_memblk_s, start_paddr)|(node_memblk_s, size)
|
||||||
|
----------------------------------------------------------------
|
||||||
|
|
||||||
|
The size of a struct node_memblk_s and the offsets of the
|
||||||
|
node_memblk_s's members. Used to compute the number of nodes.
|
||||||
|
|
||||||
|
PGTABLE_3|PGTABLE_4
|
||||||
|
-------------------
|
||||||
|
|
||||||
|
User-space tools need to know whether the crash kernel was in 3-level or
|
||||||
|
4-level paging mode. Used to distinguish the page table.
|
||||||
|
|
||||||
|
=====
|
||||||
|
ARM64
|
||||||
|
=====
|
||||||
|
|
||||||
|
VA_BITS
|
||||||
|
-------
|
||||||
|
|
||||||
|
The maximum number of bits for virtual addresses. Used to compute the
|
||||||
|
virtual memory ranges.
|
||||||
|
|
||||||
|
kimage_voffset
|
||||||
|
--------------
|
||||||
|
|
||||||
|
The offset between the kernel virtual and physical mappings. Used to
|
||||||
|
translate virtual to physical addresses.
|
||||||
|
|
||||||
|
PHYS_OFFSET
|
||||||
|
-----------
|
||||||
|
|
||||||
|
Indicates the physical address of the start of memory. Similar to
|
||||||
|
kimage_voffset, which is used to translate virtual to physical
|
||||||
|
addresses.
|
||||||
|
|
||||||
|
KERNELOFFSET
|
||||||
|
------------
|
||||||
|
|
||||||
|
The kernel randomization offset. Used to compute the page offset. If
|
||||||
|
KASLR is disabled, this value is zero.
|
||||||
|
|
||||||
|
====
|
||||||
|
arm
|
||||||
|
====
|
||||||
|
|
||||||
|
ARM_LPAE
|
||||||
|
--------
|
||||||
|
|
||||||
|
It indicates whether the crash kernel supports large physical address
|
||||||
|
extensions. Used to translate virtual to physical addresses.
|
||||||
|
|
||||||
|
====
|
||||||
|
s390
|
||||||
|
====
|
||||||
|
|
||||||
|
lowcore_ptr
|
||||||
|
----------
|
||||||
|
|
||||||
|
An array with a pointer to the lowcore of every CPU. Used to print the
|
||||||
|
psw and all registers information.
|
||||||
|
|
||||||
|
high_memory
|
||||||
|
-----------
|
||||||
|
|
||||||
|
Used to get the vmalloc_start address from the high_memory symbol.
|
||||||
|
|
||||||
|
(lowcore_ptr, NR_CPUS)
|
||||||
|
----------------------
|
||||||
|
|
||||||
|
The maximum number of CPUs.
|
||||||
|
|
||||||
|
=======
|
||||||
|
powerpc
|
||||||
|
=======
|
||||||
|
|
||||||
|
|
||||||
|
node_data|(node_data, MAX_NUMNODES)
|
||||||
|
-----------------------------------
|
||||||
|
|
||||||
|
See above.
|
||||||
|
|
||||||
|
contig_page_data
|
||||||
|
----------------
|
||||||
|
|
||||||
|
See above.
|
||||||
|
|
||||||
|
vmemmap_list
|
||||||
|
------------
|
||||||
|
|
||||||
|
The vmemmap_list maintains the entire vmemmap physical mapping. Used
|
||||||
|
to get vmemmap list count and populated vmemmap regions info. If the
|
||||||
|
vmemmap address translation information is stored in the crash kernel,
|
||||||
|
it is used to translate vmemmap kernel virtual addresses.
|
||||||
|
|
||||||
|
mmu_vmemmap_psize
|
||||||
|
-----------------
|
||||||
|
|
||||||
|
The size of a page. Used to translate virtual to physical addresses.
|
||||||
|
|
||||||
|
mmu_psize_defs
|
||||||
|
--------------
|
||||||
|
|
||||||
|
Page size definitions, i.e. 4k, 64k, or 16M.
|
||||||
|
|
||||||
|
Used to make vtop translations.
|
||||||
|
|
||||||
|
vmemmap_backing|(vmemmap_backing, list)|(vmemmap_backing, phys)|
|
||||||
|
(vmemmap_backing, virt_addr)
|
||||||
|
----------------------------------------------------------------
|
||||||
|
|
||||||
|
The vmemmap virtual address space management does not have a traditional
|
||||||
|
page table to track which virtual struct pages are backed by a physical
|
||||||
|
mapping. The virtual to physical mappings are tracked in a simple linked
|
||||||
|
list format.
|
||||||
|
|
||||||
|
User-space tools need to know the offset of list, phys and virt_addr
|
||||||
|
when computing the count of vmemmap regions.
|
||||||
|
|
||||||
|
mmu_psize_def|(mmu_psize_def, shift)
|
||||||
|
------------------------------------
|
||||||
|
|
||||||
|
The size of a struct mmu_psize_def and the offset of mmu_psize_def's
|
||||||
|
member.
|
||||||
|
|
||||||
|
Used in vtop translations.
|
||||||
|
|
||||||
|
==
|
||||||
|
sh
|
||||||
|
==
|
||||||
|
|
||||||
|
node_data|(node_data, MAX_NUMNODES)
|
||||||
|
-----------------------------------
|
||||||
|
|
||||||
|
See above.
|
||||||
|
|
||||||
|
X2TLB
|
||||||
|
-----
|
||||||
|
|
||||||
|
Indicates whether the crashed kernel enabled SH extended mode.
|
||||||
|
|
@ -352,6 +352,8 @@ void machine_kexec(struct kimage *image)
|
||||||
|
|
||||||
void arch_crash_save_vmcoreinfo(void)
|
void arch_crash_save_vmcoreinfo(void)
|
||||||
{
|
{
|
||||||
|
u64 sme_mask = sme_me_mask;
|
||||||
|
|
||||||
VMCOREINFO_NUMBER(phys_base);
|
VMCOREINFO_NUMBER(phys_base);
|
||||||
VMCOREINFO_SYMBOL(init_top_pgt);
|
VMCOREINFO_SYMBOL(init_top_pgt);
|
||||||
vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
|
vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
|
||||||
|
|
@ -364,6 +366,7 @@ void arch_crash_save_vmcoreinfo(void)
|
||||||
vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
|
vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
|
||||||
kaslr_offset());
|
kaslr_offset());
|
||||||
VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
|
VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
|
||||||
|
VMCOREINFO_NUMBER(sme_mask);
|
||||||
}
|
}
|
||||||
|
|
||||||
/* arch-dependent functionality related to kexec file-based syscall */
|
/* arch-dependent functionality related to kexec file-based syscall */
|
||||||
|
|
|
||||||
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