| Age | Commit message (Collapse) | Author | Files | Lines |
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In case a file has an invalid context set, in an AVC record generated
upon access to such file, the target context is always reported as
unlabeled. This patch adds new optional fields to the AVC record
(srawcon and trawcon) that report the actual context string if it
differs from the one reported in scontext/tcontext. This is useful for
diagnosing SELinux denials involving invalid contexts.
To trigger an AVC that illustrates this situation:
# setenforce 0
# touch /tmp/testfile
# setfattr -n security.selinux -v system_u:object_r:banana_t:s0 /tmp/testfile
# runcon system_u:system_r:sshd_t:s0 cat /tmp/testfile
AVC before:
type=AVC msg=audit(1547801083.248:11): avc: denied { open } for pid=1149 comm="cat" path="/tmp/testfile" dev="tmpfs" ino=6608 scontext=system_u:system_r:sshd_t:s0 tcontext=system_u:object_r:unlabeled_t:s15:c0.c1023 tclass=file permissive=1
AVC after:
type=AVC msg=audit(1547801083.248:11): avc: denied { open } for pid=1149 comm="cat" path="/tmp/testfile" dev="tmpfs" ino=6608 scontext=system_u:system_r:sshd_t:s0 tcontext=system_u:object_r:unlabeled_t:s15:c0.c1023 tclass=file permissive=1 trawcon=system_u:object_r:banana_t:s0
Note that it is also possible to encounter this situation with the
'scontext' field - e.g. when a new policy is loaded while a process is
running, whose context is not valid in the new policy.
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1135683
Cc: Daniel Walsh <dwalsh@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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We don't need to crash the machine in these cases. Let's just detect the
buggy state early and error out with a warning.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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avc_dump_av() and avc_dump_query() are each used only in one place. Get
rid of them and open code their contents in the call sites.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Ignore all selinux_inode_notifysecctx() calls on mounts with SBLABEL_MNT
flag unset. This is achived by returning -EOPNOTSUPP for this case in
selinux_inode_setsecurtity() (because that function should not be called
in such case anyway) and translating this error to 0 in
selinux_inode_notifysecctx().
This fixes behavior of kernfs-based filesystems when mounted with the
'context=' option. Before this patch, if a node's context had been
explicitly set to a non-default value and later the filesystem has been
remounted with the 'context=' option, then this node would show up as
having the manually-set context and not the mount-specified one.
Steps to reproduce:
# mount -t cgroup2 cgroup2 /sys/fs/cgroup/unified
# chcon unconfined_u:object_r:user_home_t:s0 /sys/fs/cgroup/unified/cgroup.stat
# ls -lZ /sys/fs/cgroup/unified
total 0
-r--r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Dec 13 10:41 cgroup.controllers
-rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Dec 13 10:41 cgroup.max.depth
-rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Dec 13 10:41 cgroup.max.descendants
-rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Dec 13 10:41 cgroup.procs
-r--r--r--. 1 root root unconfined_u:object_r:user_home_t:s0 0 Dec 13 10:41 cgroup.stat
-rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Dec 13 10:41 cgroup.subtree_control
-rw-r--r--. 1 root root system_u:object_r:cgroup_t:s0 0 Dec 13 10:41 cgroup.threads
# umount /sys/fs/cgroup/unified
# mount -o context=system_u:object_r:tmpfs_t:s0 -t cgroup2 cgroup2 /sys/fs/cgroup/unified
Result before:
# ls -lZ /sys/fs/cgroup/unified
total 0
-r--r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.controllers
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.max.depth
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.max.descendants
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.procs
-r--r--r--. 1 root root unconfined_u:object_r:user_home_t:s0 0 Dec 13 10:41 cgroup.stat
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.subtree_control
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.threads
Result after:
# ls -lZ /sys/fs/cgroup/unified
total 0
-r--r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.controllers
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.max.depth
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.max.descendants
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.procs
-r--r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.stat
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.subtree_control
-rw-r--r--. 1 root root system_u:object_r:tmpfs_t:s0 0 Dec 13 10:41 cgroup.threads
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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In the SECURITY_FS_USE_MNTPOINT case we never want to allow relabeling
files/directories, so we should never set the SBLABEL_MNT flag. The
'special handling' in selinux_is_sblabel_mnt() is only intended for when
the behavior is set to SECURITY_FS_USE_GENFS.
While there, make the logic in selinux_is_sblabel_mnt() more explicit
and add a BUILD_BUG_ON() to make sure that introducing a new
SECURITY_FS_USE_* forces a review of the logic.
Fixes: d5f3a5f6e7e7 ("selinux: add security in-core xattr support for pstore and debugfs")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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commit bda0be7ad9948 ("security: make inode_follow_link RCU-walk aware")
switched selinux_inode_follow_link() to use avc_has_perm_flags() and
pass down the MAY_NOT_BLOCK flag if called during RCU walk. However,
the only test of MAY_NOT_BLOCK occurs during slow_avc_audit()
and only if passing an inode as audit data (LSM_AUDIT_DATA_INODE). Since
selinux_inode_follow_link() passes a dentry directly, passing MAY_NOT_BLOCK
here serves no purpose. Switch selinux_inode_follow_link() to use
avc_has_perm() and drop avc_has_perm_flags() since there are no other
users.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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commit 0dc1ba24f7fff6 ("SELINUX: Make selinux cache VFS RCU walks safe")
results in no audit messages at all if in permissive mode because the
cache is updated during the rcu walk and thus no denial occurs on
the subsequent ref walk. Fix this by not updating the cache when
performing a non-blocking permission check. This only affects search
and symlink read checks during rcu walk.
Fixes: 0dc1ba24f7fff6 ("SELINUX: Make selinux cache VFS RCU walks safe")
Reported-by: BMK <bmktuwien@gmail.com>
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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The semantics of what "in core" means for the mincore() system call are
somewhat unclear, but Linux has always (since 2.3.52, which is when
mincore() was initially done) treated it as "page is available in page
cache" rather than "page is mapped in the mapping".
The problem with that traditional semantic is that it exposes a lot of
system cache state that it really probably shouldn't, and that users
shouldn't really even care about.
So let's try to avoid that information leak by simply changing the
semantics to be that mincore() counts actual mapped pages, not pages
that might be cheaply mapped if they were faulted (note the "might be"
part of the old semantics: being in the cache doesn't actually guarantee
that you can access them without IO anyway, since things like network
filesystems may have to revalidate the cache before use).
In many ways the old semantics were somewhat insane even aside from the
information leak issue. From the very beginning (and that beginning is
a long time ago: 2.3.52 was released in March 2000, I think), the code
had a comment saying
Later we can get more picky about what "in core" means precisely.
and this is that "later". Admittedly it is much later than is really
comfortable.
NOTE! This is a real semantic change, and it is for example known to
change the output of "fincore", since that program literally does a
mmmap without populating it, and then doing "mincore()" on that mapping
that doesn't actually have any pages in it.
I'm hoping that nobody actually has any workflow that cares, and the
info leak is real.
We may have to do something different if it turns out that people have
valid reasons to want the old semantics, and if we can limit the
information leak sanely.
Cc: Kevin Easton <kevin@guarana.org>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Masatake YAMATO <yamato@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit 594cc251fdd0 ("make 'user_access_begin()' do 'access_ok()'")
broke both alpha and SH booting in qemu, as noticed by Guenter Roeck.
It turns out that the bug wasn't actually in that commit itself (which
would have been surprising: it was mostly a no-op), but in how the
addition of access_ok() to the strncpy_from_user() and strnlen_user()
functions now triggered the case where those functions would test the
access of the very last byte of the user address space.
The string functions actually did that user range test before too, but
they did it manually by just comparing against user_addr_max(). But
with user_access_begin() doing the check (using "access_ok()"), it now
exposed problems in the architecture implementations of that function.
For example, on alpha, the access_ok() helper macro looked like this:
#define __access_ok(addr, size) \
((get_fs().seg & (addr | size | (addr+size))) == 0)
and what it basically tests is of any of the high bits get set (the
USER_DS masking value is 0xfffffc0000000000).
And that's completely wrong for the "addr+size" check. Because it's
off-by-one for the case where we check to the very end of the user
address space, which is exactly what the strn*_user() functions do.
Why? Because "addr+size" will be exactly the size of the address space,
so trying to access the last byte of the user address space will fail
the __access_ok() check, even though it shouldn't. As a result, the
user string accessor functions failed consistently - because they
literally don't know how long the string is going to be, and the max
access is going to be that last byte of the user address space.
Side note: that alpha macro is buggy for another reason too - it re-uses
the arguments twice.
And SH has another version of almost the exact same bug:
#define __addr_ok(addr) \
((unsigned long __force)(addr) < current_thread_info()->addr_limit.seg)
so far so good: yes, a user address must be below the limit. But then:
#define __access_ok(addr, size) \
(__addr_ok((addr) + (size)))
is wrong with the exact same off-by-one case: the case when "addr+size"
is exactly _equal_ to the limit is actually perfectly fine (think "one
byte access at the last address of the user address space")
The SH version is actually seriously buggy in another way: it doesn't
actually check for overflow, even though it did copy the _comment_ that
talks about overflow.
So it turns out that both SH and alpha actually have completely buggy
implementations of access_ok(), but they happened to work in practice
(although the SH overflow one is a serious serious security bug, not
that anybody likely cares about SH security).
This fixes the problems by using a similar macro on both alpha and SH.
It isn't trying to be clever, the end address is based on this logic:
unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;
which basically says "add start and length, and then subtract one unless
the length was zero". We can't subtract one for a zero length, or we'd
just hit an underflow instead.
For a lot of access_ok() users the length is a constant, so this isn't
actually as expensive as it initially looks.
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add support for the Adiantum encryption mode to fscrypt. Adiantum is a
tweakable, length-preserving encryption mode with security provably
reducible to that of XChaCha12 and AES-256, subject to a security bound.
It's also a true wide-block mode, unlike XTS. See the paper
"Adiantum: length-preserving encryption for entry-level processors"
(https://eprint.iacr.org/2018/720.pdf) for more details. Also see
commit 059c2a4d8e16 ("crypto: adiantum - add Adiantum support").
On sufficiently long messages, Adiantum's bottlenecks are XChaCha12 and
the NH hash function. These algorithms are fast even on processors
without dedicated crypto instructions. Adiantum makes it feasible to
enable storage encryption on low-end mobile devices that lack AES
instructions; currently such devices are unencrypted. On ARM Cortex-A7,
on 4096-byte messages Adiantum encryption is about 4 times faster than
AES-256-XTS encryption; decryption is about 5 times faster.
In fscrypt, Adiantum is suitable for encrypting both file contents and
names. With filenames, it fixes a known weakness: when two filenames in
a directory share a common prefix of >= 16 bytes, with CTS-CBC their
encrypted filenames share a common prefix too, leaking information.
Adiantum does not have this problem.
Since Adiantum also accepts long tweaks (IVs), it's also safe to use the
master key directly for Adiantum encryption rather than deriving
per-file keys, provided that the per-file nonce is included in the IVs
and the master key isn't used for any other encryption mode. This
configuration saves memory and improves performance. A new fscrypt
policy flag is added to allow users to opt-in to this configuration.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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Remove the dot-prefixing since it is just a matter of the
.gitignore file.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Make simply skips a missing rule when it is marked as .PHONY.
Remove the dummy targets.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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You do not have to use define ... endef for filechk_* rules.
For simple cases, the use of assignment looks cleaner, IMHO.
I updated the usage for scripts/Kbuild.include in case somebody
misunderstands the 'define ... endif' is the requirement.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
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Now that Kbuild automatically creates asm-generic wrappers for missing
mandatory headers, it is redundant to list the same headers in
generic-y and mandatory-y.
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
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Some time ago, Sam pointed out a certain degree of overwrap between
generic-y and mandatory-y. (https://lkml.org/lkml/2017/7/10/121)
I tweaked the meaning of mandatory-y a little bit; now it defines the
minimum set of ASM headers that all architectures must have.
If arch does not have specific implementation of a mandatory header,
Kbuild will let it fallback to the asm-generic one by automatically
generating a wrapper. This will allow to drop lots of redundant
generic-y defines.
Previously, "mandatory" was used in the context of UAPI, but I guess
this can be extended to kernel space ASM headers.
Suggested-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
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These comments are leftovers of commit fcc8487d477a ("uapi: export all
headers under uapi directories").
Prior to that commit, exported headers must be explicitly added to
header-y. Now, all headers under the uapi/ directories are exported.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This commit removes redundant generic-y defines in
arch/riscv/include/asm/Kbuild.
[1] It is redundant to define the same generic-y in both
arch/$(ARCH)/include/asm/Kbuild and
arch/$(ARCH)/include/uapi/asm/Kbuild.
Remove the following generic-y:
errno.h
fcntl.h
ioctl.h
ioctls.h
ipcbuf.h
mman.h
msgbuf.h
param.h
poll.h
posix_types.h
resource.h
sembuf.h
setup.h
shmbuf.h
signal.h
socket.h
sockios.h
stat.h
statfs.h
swab.h
termbits.h
termios.h
types.h
[2] It is redundant to define generic-y when arch-specific
implementation exists in arch/$(ARCH)/include/asm/*.h
Remove the following generic-y:
cacheflush.h
module.h
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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filechk_* rules often consist of multiple 'echo' lines. They must be
surrounded with { } or ( ) to work correctly. Otherwise, only the
string from the last 'echo' would be written into the target.
Let's take care of that in the 'filechk' in scripts/Kbuild.include
to clean up filechk_* rules.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special
target"), the target file is automatically deleted on failure.
The boilerplate code
... || { rm -f $@; false; }
is unneeded.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Commit 3a2429e1faf4 ("kbuild: change if_changed_rule for multi-line
recipe") and commit 4f0e3a57d6eb ("kbuild: Add support for DT binding
schema checks") came in via different sub-systems.
This is a follow-up cleanup.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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The only/last user of UIMAGE_IN/OUT was removed by commit 4722a3e6b716
("microblaze: fix multiple bugs in arch/microblaze/boot/Makefile").
The input and output should always be $< and $@.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Currently, CONFIG_JUMP_LABEL just means "I _want_ to use jump label".
The jump label is controlled by HAVE_JUMP_LABEL, which is defined
like this:
#if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL)
# define HAVE_JUMP_LABEL
#endif
We can improve this by testing 'asm goto' support in Kconfig, then
make JUMP_LABEL depend on CC_HAS_ASM_GOTO.
Ugly #ifdef HAVE_JUMP_LABEL will go away, and CONFIG_JUMP_LABEL will
match to the real kernel capability.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
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As mentioned in the info pages of gas, the '.align' pseudo op's
interpretation of the alignment value is architecture specific.
It might either be a byte value or taken to the power of two.
On ARM it's actually the latter which leads to unnecessary large
alignments of 16 bytes for 32 bit builds or 256 bytes for 64 bit
builds.
Fix this by switching to '.balign' instead which is consistent
across all architectures.
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Coccinelle doesn't always have access to the values of named
(#define) constants, and they may likely often be bound to true
and false values anyway, resulting in false positives. So stop
warning about them.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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Avoid reporting on the use of an iterator index variable when
the variable is redeclared.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This has never been used.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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This commit removes redundant generic-y defines in
arch/nds32/include/asm/Kbuild.
[1] It is redundant to define the same generic-y in both
arch/$(ARCH)/include/asm/Kbuild and
arch/$(ARCH)/include/uapi/asm/Kbuild.
Remove the following generic-y:
bitsperlong.h
bpf_perf_event.h
errno.h
fcntl.h
ioctl.h
ioctls.h
mman.h
shmbuf.h
stat.h
[2] It is redundant to define generic-y when arch-specific
implementation exists in arch/$(ARCH)/include/asm/*.h
Remove the following generic-y:
ftrace.h
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
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kernel/dma/Kconfig globally defines HAS_DMA as follows:
config HAS_DMA
bool
depends on !NO_DMA
default y
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
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Fixes build break on most ARM/ARM64 defconfigs:
lib/genalloc.c: In function 'gen_pool_add_virt':
lib/genalloc.c:190:10: error: implicit declaration of function 'vzalloc_node'; did you mean 'kzalloc_node'?
lib/genalloc.c:190:8: warning: assignment to 'struct gen_pool_chunk *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
lib/genalloc.c: In function 'gen_pool_destroy':
lib/genalloc.c:254:3: error: implicit declaration of function 'vfree'; did you mean 'kfree'?
Fixes: 6862d2fc8185 ('lib/genalloc.c: use vzalloc_node() to allocate the bitmap')
Cc: Huang Shijie <sjhuang@iluvatar.ai>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Skidanov <alexey.skidanov@intel.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We need to return a dma_addr_t even if we don't have a kernel mapping.
Do so by consolidating the phys_to_dma call in a single place and jump
to it from all the branches that return successfully.
Fixes: bfd56cd60521 ("dma-mapping: support highmem in the generic remap allocator")
Reported-by: Liviu Dudau <liviu@dudau.co.uk
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Liviu Dudau <liviu@dudau.co.uk>
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In many cases we don't have to create a GART mapping at all, which
also means there is nothing to unmap. Fix the range check that was
incorrectly modified when removing the mapping_error method.
Fixes: 9e8aa6b546 ("x86/amd_gart: remove the mapping_error dma_map_ops method")
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Michal Kubecek <mkubecek@suse.cz>
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Some non-generic ia64 configs don't build swiotlb, and thus should not
pull in the generic non-coherent DMA infrastructure.
Fixes: 68c608345c ("swiotlb: remove dma_mark_clean")
Reported-by: Tony Luck <tony.luck@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This has been broken forever, and nobody ever really noticed because
it's purely a performance issue.
Long long ago, in commit 6175ddf06b61 ("x86: Clean up mem*io functions")
Brian Gerst simplified the memory copies to and from iomem, since on
x86, the instructions to access iomem are exactly the same as the
regular instructions.
That is technically true, and things worked, and nobody said anything.
Besides, back then the regular memcpy was pretty simple and worked fine.
Nobody noticed except for David Laight, that is. David has a testing a
TLP monitor he was writing for an FPGA, and has been occasionally
complaining about how memcpy_toio() writes things one byte at a time.
Which is completely unacceptable from a performance standpoint, even if
it happens to technically work.
The reason it's writing one byte at a time is because while it's
technically true that accesses to iomem are the same as accesses to
regular memory on x86, the _granularity_ (and ordering) of accesses
matter to iomem in ways that they don't matter to regular cached memory.
In particular, when ERMS is set, we default to using "rep movsb" for
larger memory copies. That is indeed perfectly fine for real memory,
since the whole point is that the CPU is going to do cacheline
optimizations and executes the memory copy efficiently for cached
memory.
With iomem? Not so much. With iomem, "rep movsb" will indeed work, but
it will copy things one byte at a time. Slowly and ponderously.
Now, originally, back in 2010 when commit 6175ddf06b61 was done, we
didn't use ERMS, and this was much less noticeable.
Our normal memcpy() was simpler in other ways too.
Because in fact, it's not just about using the string instructions. Our
memcpy() these days does things like "read and write overlapping values"
to handle the last bytes of the copy. Again, for normal memory,
overlapping accesses isn't an issue. For iomem? It can be.
So this re-introduces the specialized memcpy_toio(), memcpy_fromio() and
memset_io() functions. It doesn't particularly optimize them, but it
tries to at least not be horrid, or do overlapping accesses. In fact,
this uses the existing __inline_memcpy() function that we still had
lying around that uses our very traditional "rep movsl" loop followed by
movsw/movsb for the final bytes.
Somebody may decide to try to improve on it, but if we've gone almost a
decade with only one person really ever noticing and complaining, maybe
it's not worth worrying about further, once it's not _completely_ broken?
Reported-by: David Laight <David.Laight@aculab.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This actually enables the __put_user_goto() functionality in
unsafe_put_user().
For an example of the effect of this, this is the code generated for the
unsafe_put_user(signo, &infop->si_signo, Efault);
in the waitid() system call:
movl %ecx,(%rbx) # signo, MEM[(struct __large_struct *)_2]
It's just one single store instruction, along with generating an
exception table entry pointing to the Efault label case in case that
instruction faults.
Before, we would generate this:
xorl %edx, %edx
movl %ecx,(%rbx) # signo, MEM[(struct __large_struct *)_3]
testl %edx, %edx
jne .L309
with the exception table generated for that 'mov' instruction causing us
to jump to a stub that set %edx to -EFAULT and then jumped back to the
'testl' instruction.
So not only do we now get rid of the extra code in the normal sequence,
we also avoid unnecessarily keeping that extra error register live
across it all.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is finally the actual reason for the odd error handling in the
"unsafe_get/put_user()" functions, introduced over three years ago.
Using a "jump to error label" interface is somewhat odd, but very
convenient as a programming interface, and more importantly, it fits
very well with simply making the target be the exception handler address
directly from the inline asm.
The reason it took over three years to actually do this? We need "asm
goto" support for it, which only became the default on x86 last year.
It's now been a year that we've forced asm goto support (see commit
e501ce957a78 "x86: Force asm-goto"), and so let's just do it here too.
[ Side note: this commit was originally done back in 2016. The above
commentary about timing is obviously about it only now getting merged
into my real upstream tree - Linus ]
Sadly, gcc still only supports "asm goto" with asms that do not have any
outputs, so we are limited to only the put_user case for this. Maybe in
several more years we can do the get_user case too.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The alternative coding patch for parisc in kernel 4.20 broke booting
machines with PA8500-PA8700 CPUs. The problem is, that for such machines
the parisc kernel automatically utilizes huge pages to access kernel
text code, but the set_kernel_text_rw() function, which is used shortly
before applying any alternative patches, didn't used the correctly
hugepage-aligned addresses to remap the kernel text read-writeable.
Fixes: 3847dab77421 ("parisc: Add alternative coding infrastructure")
Cc: <stable@vger.kernel.org> [4.20]
Signed-off-by: Helge Deller <deller@gmx.de>
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Enable the UniPhier MIO DMAC driver. This is used as the DMA engine
for accelerating the SD/eMMC controller drivers.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
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Signed-off-by: Jens Axboe <axboe@kernel.dk>
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swap_readpage() wants to do polling to bring in pages if asked to, but
it doesn't mark the bio as being polled. Additionally, the looping
around the blk_poll() check isn't correct - if we get a zero return, we
should call io_schedule(), we can't just assume that the bio has
completed. The regular bio->bi_private check should be used for that.
Link: http://lkml.kernel.org/r/e15243a8-2cdf-c32c-ecee-f289377c8ef9@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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As per Documentation/process/submitting-patches, Co-developed-by is a
valid signature.
This commit removes the warning.
Link: http://lkml.kernel.org/r/1544808928-20002-3-git-send-email-jorge.ramirez-ortiz@linaro.org
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Himanshu Jha <himanshujha199640@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The accepted terminology will be Co-developed-by therefore lose the
capital letter from now on.
Link: http://lkml.kernel.org/r/1544808928-20002-2-git-send-email-jorge.ramirez-ortiz@linaro.org
Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Acked-by: Himanshu Jha <himanshujha199640@gmail.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Niklas Cassel <niklas.cassel@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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unreferenced object 0xffff808ec6dc5a80 (size 128):
comm "swapper/0", pid 1, jiffies 4294938063 (age 2560.530s)
hex dump (first 32 bytes):
ff ff ff ff 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b ........kkkkkkkk
6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
backtrace:
[<00000000476dcf8c>] kmem_cache_alloc_trace+0x430/0x500
[<000000004f708d37>] platform_device_register_full+0xbc/0x1e8
[<000000006c2a7ec7>] acpi_create_platform_device+0x370/0x450
[<00000000ef135642>] acpi_default_enumeration+0x34/0x78
[<000000003bd9a052>] acpi_bus_attach+0x2dc/0x3e0
[<000000003cf4f7f2>] acpi_bus_attach+0x108/0x3e0
[<000000003cf4f7f2>] acpi_bus_attach+0x108/0x3e0
[<000000002968643e>] acpi_bus_scan+0xb0/0x110
[<0000000010dd0bd7>] acpi_scan_init+0x1a8/0x410
[<00000000965b3c5a>] acpi_init+0x408/0x49c
[<00000000ed4b9fe2>] do_one_initcall+0x178/0x7f4
[<00000000a5ac5a74>] kernel_init_freeable+0x9d4/0xa9c
[<0000000070ea6c15>] kernel_init+0x18/0x138
[<00000000fb8fff06>] ret_from_fork+0x10/0x1c
[<0000000041273a0d>] 0xffffffffffffffff
Then, faddr2line pointed out this line,
/*
* This memory isn't freed when the device is put,
* I don't have a nice idea for that though. Conceptually
* dma_mask in struct device should not be a pointer.
* See http://thread.gmane.org/gmane.linux.kernel.pci/9081
*/
pdev->dev.dma_mask =
kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);
Since this leak has existed for more than 8 years and it does not
reference other parts of the memory, let kmemleak ignore it, so users
don't need to waste time reporting this in the future.
Link: http://lkml.kernel.org/r/20181206160751.36211-1-cai@gmx.us
Signed-off-by: Qian Cai <cai@gmx.us>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Multiple filesystems open code lru_to_page(). Rectify this by moving
the macro from mm_inline (which is specific to lru stuff) to the more
generic mm.h header and start using the macro where appropriate.
No functional changes.
Link: http://lkml.kernel.org/r/20181129104810.23361-1-nborisov@suse.com
Link: https://lkml.kernel.org/r/20181129075301.29087-1-nborisov@suse.com
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Pankaj gupta <pagupta@redhat.com>
Acked-by: "Yan, Zheng" <zyan@redhat.com> [ceph]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is already done for us internally by the signal machinery.
[akpm@linux-foundation.org: fix fs/buffer.c]
Link: http://lkml.kernel.org/r/20181116002713.8474-7-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is already done for us internally by the signal machinery.
Link: http://lkml.kernel.org/r/20181116002713.8474-5-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is already done for us internally by the signal machinery.
Link: http://lkml.kernel.org/r/20181116002713.8474-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is already done for us internally by the signal machinery.
Link: http://lkml.kernel.org/r/20181116002713.8474-3-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This is already done for us internally by the signal machinery.
Link: http://lkml.kernel.org/r/20181116002713.8474-2-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Moving page-tables at the PMD-level on x86 is known to be safe. Enable
this option so that we can do fast mremap when possible.
Link: http://lkml.kernel.org/r/20181108181201.88826-4-joelaf@google.com
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Suggested-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ondrej Mosnacek
Stephen Smalley
Linus Torvalds
Eric Biggers
Masahiro Yamada
Mathias Krause
Julia Lawall
Olof Johansson
Christoph Hellwig
Helge Deller
Jens Axboe
Jorge Ramirez-Ortiz
Qian Cai
Nikolay Borisov
Davidlohr Bueso
Joel Fernandes (Google)