linux-bl808/fs
Eric W. Biederman c39ab6de22 coredump: Document coredump code exclusively used by cell spufs
Oleg Nesterov recently asked[1] why is there an unshare_files in
do_coredump.  After digging through all of the callers of lookup_fd it
turns out that it is
arch/powerpc/platforms/cell/spufs/coredump.c:coredump_next_context
that needs the unshare_files in do_coredump.

Looking at the history[2] this code was also the only piece of coredump code
that required the unshare_files when the unshare_files was added.

Looking at that code it turns out that cell is also the only
architecture that implements elf_coredump_extra_notes_size and
elf_coredump_extra_notes_write.

I looked at the gdb repo[3] support for cell has been removed[4] in binutils
2.34.  Geoff Levand reports he is still getting questions on how to
run modern kernels on the PS3, from people using 3rd party firmware so
this code is not dead.  According to Wikipedia the last PS3 shipped in
Japan sometime in 2017.  So it will probably be a little while before
everyone's hardware dies.

Add some comments briefly documenting the coredump code that exists
only to support cell spufs to make it easier to understand the
coredump code.  Eventually the hardware will be dead, or their won't
be userspace tools, or the coredump code will be refactored and it
will be too difficult to update a dead architecture and these comments
make it easy to tell where to pull to remove cell spufs support.

[1] https://lkml.kernel.org/r/20201123175052.GA20279@redhat.com
[2] 179e037fc1 ("do_coredump(): make sure that descriptor table isn't shared")
[3] git://sourceware.org/git/binutils-gdb.git
[4] abf516c6931a ("Remove Cell Broadband Engine debugging support").
Link: https://lkml.kernel.org/r/87h7pdnlzv.fsf_-_@x220.int.ebiederm.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-12-10 12:57:08 -06:00
..
9p Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
adfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
affs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
afs
autofs file: Replace ksys_close with close_fd 2020-12-10 12:42:59 -06:00
befs
bfs
btrfs
cachefiles
ceph Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
cifs cifs: update internal module version number 2020-10-23 23:41:49 -05:00
coda
configfs
cramfs
crypto
debugfs
devpts
dlm
ecryptfs
efivarfs
efs
erofs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
exfat Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
exportfs
ext2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
ext4 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
f2fs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
fat
freevxfs
fscache
fuse
gfs2
hfs
hfsplus Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
hostfs
hpfs
hugetlbfs
iomap
isofs
jbd2
jffs2
jfs
kernfs
lockd
minix
nfs
nfs_common
nfsd
nilfs2 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
nls
notify file: Rename fcheck lookup_fd_rcu 2020-12-10 12:40:07 -06:00
ntfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
ocfs2
omfs
openpromfs
orangefs
overlayfs
proc proc/fd: In fdinfo seq_show don't use get_files_struct 2020-12-10 12:42:58 -06:00
pstore
qnx4
qnx6
quota
ramfs
reiserfs
romfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
squashfs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
sysfs
sysv
tracefs
ubifs
udf Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
ufs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
unicode
vboxsf
verity
xfs treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
zonefs Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
aio.c
anon_inodes.c
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf.c coredump: Document coredump code exclusively used by cell spufs 2020-12-10 12:57:08 -06:00
binfmt_elf_fdpic.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
block_dev.c
buffer.c
char_dev.c
compat_binfmt_elf.c
coredump.c coredump: Document coredump code exclusively used by cell spufs 2020-12-10 12:57:08 -06:00
d_path.c
dax.c
dcache.c
dcookies.c
direct-io.c
drop_caches.c
eventfd.c
eventpoll.c
exec.c exec: Simplify unshare_files 2020-12-10 12:39:32 -06:00
fcntl.c
fhandle.c
file.c file: Remove get_files_struct 2020-12-10 12:42:59 -06:00
file_table.c
filesystems.c
fs-writeback.c
fs_context.c
fs_parser.c
fs_pin.c
fs_struct.c
fs_types.c
fsopen.c
init.c
inode.c
internal.h
io-wq.c
io-wq.h
io_uring.c file: Rename __close_fd_get_file close_fd_get_file 2020-12-10 12:42:59 -06:00
ioctl.c
Kconfig
Kconfig.binfmt
kernel_read_file.c
libfs.c
locks.c file: Factor files_lookup_fd_locked out of fcheck_files 2020-12-10 12:39:59 -06:00
Makefile
mbcache.c
mount.h
mpage.c
namei.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
namespace.c Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-24 12:26:05 -07:00
no-block.c
nsfs.c
open.c file: Rename __close_fd to close_fd and remove the files parameter 2020-12-10 12:42:59 -06:00
pipe.c
pnode.c
pnode.h
posix_acl.c
proc_namespace.c
read_write.c
readdir.c
remap_range.c
select.c
seq_file.c
signalfd.c
splice.c io_uring-5.10-2020-10-24 2020-10-24 12:40:18 -07:00
stack.c
stat.c
statfs.c
super.c
sync.c
timerfd.c
userfaultfd.c
utimes.c
xattr.c