linux-toradex.git/fs/proc/vmcore.c, branch v3.11.2

s390/kdump: Disable mmap for s390

2013-07-18T11:40:18+00:00

The kdump mmap patch series (git commit 83086978c63afd7c73e1c) directly
map the PT_LOADs to memory. On s390 this does not work because the
copy_from_oldmem() function swaps [0,crashkernel size] with
[crashkernel base, crashkernel base+crashkernel size]. The swap
int copy_from_oldmem() was done in order correctly implement /dev/oldmem.

See: http://marc.info/?l=kexec&m=136940802511603&w=2

Signed-off-by: Michael Holzheu 
Signed-off-by: Martin Schwidefsky

vmcore: support mmap() on /proc/vmcore

2013-07-03T23:07:30+00:00

This patch introduces mmap_vmcore().

Don't permit writable nor executable mapping even with mprotect()
because this mmap() is aimed at reading crash dump memory.  Non-writable
mapping is also requirement of remap_pfn_range() when mapping linear
pages on non-consecutive physical pages; see is_cow_mapping().

Set VM_MIXEDMAP flag to remap memory by remap_pfn_range and by
remap_vmalloc_range_pertial at the same time for a single vma.
do_munmap() can correctly clean partially remapped vma with two
functions in abnormal case.  See zap_pte_range(), vm_normal_page() and
their comments for details.

On x86-32 PAE kernels, mmap() supports at most 16TB memory only.  This
limitation comes from the fact that the third argument of
remap_pfn_range(), pfn, is of 32-bit length on x86-32: unsigned long.

[akpm@linux-foundation.org: use min(), switch to conventional error-unwinding approach]
Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Tested-by: Maxim Uvarov 
Cc: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmcore: calculate vmcore file size from buffer size and total size of vmcore objects

2013-07-03T23:07:30+00:00

The previous patches newly added holes before each chunk of memory and
the holes need to be count in vmcore file size.  There are two ways to
count file size in such a way:

1) suppose m is a poitner to the last vmcore object in vmcore_list.
   Then file size is (m->offset + m->size), or

2) calculate sum of size of buffers for ELF header, program headers,
   ELF note segments and objects in vmcore_list.

Although 1) is more direct and simpler than 2), 2) seems better in that
it reflects internal object structure of /proc/vmcore.  Thus, this patch
changes get_vmcore_size_elf{64, 32} so that it calculates size in the
way of 2).

As a result, both get_vmcore_size_elf{64, 32} have the same definition.
Merge them as get_vmcore_size.

Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmcore: allow user process to remap ELF note segment buffer

2013-07-03T23:07:30+00:00

Now ELF note segment has been copied in the buffer on vmalloc memory.
To allow user process to remap the ELF note segment buffer with
remap_vmalloc_page, the corresponding VM area object has to have
VM_USERMAP flag set.

[akpm@linux-foundation.org: use the conventional comment layout]
Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmcore: allocate ELF note segment in the 2nd kernel vmalloc memory

2013-07-03T23:07:30+00:00

The reasons why we don't allocate ELF note segment in the 1st kernel
(old memory) on page boundary is to keep backward compatibility for old
kernels, and that if doing so, we waste not a little memory due to
round-up operation to fit the memory to page boundary since most of the
buffers are in per-cpu area.

ELF notes are per-cpu, so total size of ELF note segments depends on
number of CPUs.  The current maximum number of CPUs on x86_64 is 5192,
and there's already system with 4192 CPUs in SGI, where total size
amounts to 1MB.  This can be larger in the near future or possibly even
now on another architecture that has larger size of note per a single
cpu.  Thus, to avoid the case where memory allocation for large block
fails, we allocate vmcore objects on vmalloc memory.

This patch adds elfnotes_buf and elfnotes_sz variables to keep pointer
to the ELF note segment buffer and its size.  There's no longer the
vmcore object that corresponds to the ELF note segment in vmcore_list.
Accordingly, read_vmcore() has new case for ELF note segment and
set_vmcore_list_offsets_elf{64,32}() and other helper functions starts
calculating offset from sum of size of ELF headers and size of ELF note
segment.

[akpm@linux-foundation.org: use min(), fix error-path vzalloc() leaks]
Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmcore: treat memory chunks referenced by PT_LOAD program header entries in page-size boundary in vmcore_list

2013-07-03T23:07:30+00:00

Treat memory chunks referenced by PT_LOAD program header entries in
page-size boundary in vmcore_list.  Formally, for each range [start,
end], we set up the corresponding vmcore object in vmcore_list to
[rounddown(start, PAGE_SIZE), roundup(end, PAGE_SIZE)].

This change affects layout of /proc/vmcore.  The gaps generated by the
rearrangement are newly made visible to applications as holes.
Concretely, they are two ranges [rounddown(start, PAGE_SIZE), start] and
[end, roundup(end, PAGE_SIZE)].

Suppose variable m points at a vmcore object in vmcore_list, and
variable phdr points at the program header of PT_LOAD type the variable
m corresponds to.  Then, pictorially:

  m->offset                    +---------------+
                               | hole          |
phdr->p_offset =               +---------------+
  m->offset + (paddr - start)  |               |\
                               | kernel memory | phdr->p_memsz
                               |               |/
                               +---------------+
                               | hole          |
  m->offset + m->size          +---------------+

where m->offset and m->offset + m->size are always page-size aligned.

Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmcore: allocate buffer for ELF headers on page-size alignment

2013-07-03T23:07:30+00:00

Allocate ELF headers on page-size boundary using __get_free_pages()
instead of kmalloc().

Later patch will merge PT_NOTE entries into a single unique one and
decrease the buffer size actually used.  Keep original buffer size in
variable elfcorebuf_sz_orig to kfree the buffer later and actually used
buffer size with rounded up to page-size boundary in variable
elfcorebuf_sz separately.

The size of part of the ELF buffer exported from /proc/vmcore is
elfcorebuf_sz.

The merged, removed PT_NOTE entries, i.e.  the range [elfcorebuf_sz,
elfcorebuf_sz_orig], is filled with 0.

Use size of the ELF headers as an initial offset value in
set_vmcore_list_offsets_elf{64,32} and
process_ptload_program_headers_elf{64,32} in order to indicate that the
offset includes the holes towards the page boundary.

As a result, both set_vmcore_list_offsets_elf{64,32} have the same
definition.  Merge them as set_vmcore_list_offsets.

[akpm@linux-foundation.org: add free_elfcorebuf(), cleanups]
Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmcore: clean up read_vmcore()

2013-07-03T23:07:30+00:00

Rewrite part of read_vmcore() that reads objects in vmcore_list in the
same way as part reading ELF headers, by which some duplicated and
redundant codes are removed.

Signed-off-by: HATAYAMA Daisuke 
Acked-by: Vivek Goyal 
Cc: KOSAKI Motohiro 
Cc: Atsushi Kumagai 
Cc: Lisa Mitchell 
Cc: Zhang Yanfei 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: Supply a function to remove a proc entry by PDE

2013-05-01T21:29:46+00:00

Supply a function (proc_remove()) to remove a proc entry (and any subtree
rooted there) by proc_dir_entry pointer rather than by name and (optionally)
root dir entry pointer.  This allows us to eliminate all remaining pde->name
accesses outside of procfs.

Signed-off-by: David Howells 
Acked-by: Grant Likely 
cc: linux-acpi@vger.kernel.org
cc: openipmi-developer@lists.sourceforge.net
cc: devicetree-discuss@lists.ozlabs.org
cc: linux-pci@vger.kernel.org
cc: netdev@vger.kernel.org
cc: netfilter-devel@vger.kernel.org
cc: alsa-devel@alsa-project.org
Signed-off-by: Al Viro

proc: Split kcore bits from linux/procfs.h into linux/kcore.h

2013-04-29T19:42:02+00:00

Split kcore bits from linux/procfs.h into linux/kcore.h.

Signed-off-by: David Howells 
Acked-by: KOSAKI Motohiro 
Acked-by: Ralf Baechle 
cc: linux-mips@linux-mips.org
cc: sparclinux@vger.kernel.org
cc: x86@kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Al Viro