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This clarifies the rules for min()/max()/clamp() type checking and makes
them a much more efficient macro expansion.
In particular, we now look at the type and range of the inputs to see
whether they work together, generating a mask of acceptable comparisons,
and then just verifying that the inputs have a shared case:
- an expression with a signed type can be used for
(1) signed comparisons
(2) unsigned comparisons if it is statically known to have a
non-negative value
- an expression with an unsigned type can be used for
(3) unsigned comparison
(4) signed comparisons if the type is smaller than 'int' and thus
the C integer promotion rules will make it signed anyway
Here rule (1) and (3) are obvious, and rule (2) is important in order to
allow obvious trivial constants to be used together with unsigned
values.
Rule (4) is not necessarily a good idea, but matches what we used to do,
and we have extant cases of this situation in the kernel. Notably with
bcachefs having an expression like
min(bch2_bucket_sectors_dirty(a), ca->mi.bucket_size)
where bch2_bucket_sectors_dirty() returns an 's64', and
'ca->mi.bucket_size' is of type 'u16'.
Technically that bcachefs comparison is clearly sensible on a C type
level, because the 'u16' will go through the normal C integer promotion,
and become 'int', and then we're comparing two signed values and
everything looks sane.
However, it's not entirely clear that a 'min(s64,u16)' operation makes a
lot of conceptual sense, and it's possible that we will remove rule (4).
After all, the _reason_ we have these complicated type checks is exactly
that the C type promotion rules are not very intuitive.
But at least for now the rule is in place for backwards compatibility.
Also note that rule (2) existed before, but is hugely relaxed by this
commit. It used to be true only for the simplest compile-time
non-negative integer constants. The new macro model will allow cases
where the compiler can trivially see that an expression is non-negative
even if it isn't necessarily a constant.
For example, the amdgpu driver does
min_t(size_t, sizeof(fru_info->serial), pia[addr] & 0x3F));
because our old 'min()' macro would see that 'pia[addr] & 0x3F' is of
type 'int' and clearly not a C constant expression, so doing a 'min()'
with a 'size_t' is a signedness violation.
Our new 'min()' macro still sees that 'pia[addr] & 0x3F' is of type
'int', but is smart enough to also see that it is clearly non-negative,
and thus would allow that case without any complaints.
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The 'mptcp_subflow_context' structure has two items related to the
backup flags:
- 'backup': the subflow has been marked as backup by the other peer
- 'request_bkup': the backup flag has been set by the host
Before this patch, the scheduler was only looking at the 'backup' flag.
That can make sense in some cases, but it looks like that's not what we
wanted for the general use, because either the path-manager was setting
both of them when sending an MP_PRIO, or the receiver was duplicating
the 'backup' flag in the subflow request.
Note that the use of these two flags in the path-manager are going to be
fixed in the next commits, but this change here is needed not to modify
the behaviour.
Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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We had a nice name scheme in ALSA sequencer UMP binding for each
sequencer port referring to each assigned Function Block name, while
the legacy rawmidi refers only to the UMP Endpoint name. It's better
to align both.
This patch moves the UMP Group attribute update functions into the
core UMP code from the sequencer binding code, and improve the
substream name of the legacy rawmidi.
Link: https://patch.msgid.link/20240729141315.18253-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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struct snd_kcontrol contains a flex array of snd_kcontrol_volatile
objects at its end, and the array size is stored in count field.
This can be annotated gracefully with __counted_by() for catching
possible array overflows.
One additional change is the order of the count field initialization;
The assignment of the count field is moved before assignment of vd[]
elements for avoiding false-positive warnings from compilers.
Link: https://patch.msgid.link/20240726152840.8629-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Pull outstanding commits from 6.11 queue into fixes.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Unit tests are more ergonomic and simpler to understand if they don't
have to hoist a bunch of code into the test harness init and exit
functions. Add some test managed wrappers for the clk APIs so that clk
unit tests can write more code in the actual test and less code in the
harness.
Only add APIs that are used for now. More wrappers can be added in the
future as necessary.
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-7-sboyd@kernel.org
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Introduce KUnit resource wrappers around platform_driver_register(),
platform_device_alloc(), and platform_device_add() so that test authors
can register platform drivers/devices from their tests and have the
drivers/devices automatically be unregistered when the test is done.
This makes test setup code simpler when a platform driver or platform
device is needed. Add a few test cases at the same time to make sure the
APIs work as intended.
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-6-sboyd@kernel.org
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Add test managed wrappers for of_overlay_apply() that automatically
removes the overlay when the test is finished. This API is intended for
use by KUnit tests that test code which relies on 'struct device_node's
and of_*() APIs.
KUnit tests will call of_overlay_apply_kunit() to load an overlay that's
been built into the kernel image. When the test is complete, the overlay
will be removed.
This has a few benefits:
1) It keeps the tests hermetic because the overlay is removed when the
test is complete. Tests won't even be aware that an overlay was
loaded in another test.
2) The overlay code can live right next to the unit test that loads it.
The overlay and the unit test can be compiled into one kernel module
if desired.
3) We can test different device tree configurations by loading
different overlays. The overlays can be written for a specific test,
and there can be many of them loaded per-test without needing to jam
all possible combinations into one DTB.
4) It also allows KUnit to test device tree dependent code on any
architecture, not just UML. This allows KUnit tests to test
architecture specific device tree code.
There are some potential pitfalls though. Test authors need to be
careful to not overwrite properties in the live tree. The easiest way to
do this is to add and remove nodes with a 'kunit-' prefix, almost
guaranteeing that the same node won't be present in the tree loaded at
boot.
Suggested-by: Rob Herring <robh@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Saravana Kannan <saravanak@google.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20240718210513.3801024-3-sboyd@kernel.org
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Introduce the function ata_dev_print_quirks() to print the quirk flags
that will be applied to a scanned device. This new function is called
from ata_dev_quirks() when a match on a device model or device model
and revision is found for a device in the __ata_dev_quirks array.
To implement this function, the ATA_QUIRK_ flags are redefined using
the new enum ata_quirk which defines the bit shift for each quirk
flag. The array of strings ata_quirk_names is used to define the name
of each flag, which are printed by ata_dev_print_quirks().
Example output for a device listed in the __ata_dev_quirks array and
which has the ATA_QUIRK_DISABLE flag applied:
[10193.461270] ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
[10193.469190] ata1.00: Model 'ASMT109x- Config', rev '2143 5', applying quirks: disable
[10193.469195] ata1.00: unsupported device, disabling
[10193.481564] ata1.00: disable device
enum ata_quirk also defines the __ATA_QUIRK_MAX value as one plus the
last quirk flag defined. This value is used in ata_dev_quirks() to add a
build time check that all quirk flags fit within the unsigned int
(32-bits) quirks field of struct ata_device.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Igor Pylypiv <ipylypiv@google.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
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According to Wiktionary, the verb "hork" is computing slang defined as
"To foul up; to be occupied with difficulty, tangle, or unpleasantness;
to be broken" (https://en.wiktionary.org/wiki/hork#Verb). libata uses
this with the term "horkage" to refer to broken device features. Given
that this term is not widely used and its meaning unknown to many,
rename it to the more commonly used term "quirk", similar to many other
places in the kernel.
The renaming done is:
1) Rename all ATA_HORKAGE_XXX flags to ATA_QUIRK_XXX
2) Rename struct ata_device horkage field to quirks
3) Rename struct ata_blacklist_entry to struct ata_dev_quirks_entry. The
array of these structures defining quirks for known devices is
renamed __ata_dev_quirks.
4) The functions ata_dev_blacklisted() and ata_force_horkage() are
renamed to ata_dev_quirks() and ata_force_quirks() respectively.
5) All the force_horkage_xxx() macros are renamed to force_quirk_xxx()
And while at it, make sure that the type "unsigned int" is used
consistantly for quirk flags variables and data structure fields.
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Igor Pylypiv <ipylypiv@google.com>
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GCC and LLVM define a no_caller_saved_registers function attribute.
This attribute means that function scratches only some of
the caller saved registers defined by ABI.
For BPF the set of such registers could be defined as follows:
- R0 is scratched only if function is non-void;
- R1-R5 are scratched only if corresponding parameter type is defined
in the function prototype.
This commit introduces flag bpf_func_prot->allow_nocsr.
If this flag is set for some helper function, verifier assumes that
it follows no_caller_saved_registers calling convention.
The contract between kernel and clang allows to simultaneously use
such functions and maintain backwards compatibility with old
kernels that don't understand no_caller_saved_registers calls
(nocsr for short):
- clang generates a simple pattern for nocsr calls, e.g.:
r1 = 1;
r2 = 2;
*(u64 *)(r10 - 8) = r1;
*(u64 *)(r10 - 16) = r2;
call %[to_be_inlined]
r2 = *(u64 *)(r10 - 16);
r1 = *(u64 *)(r10 - 8);
r0 = r1;
r0 += r2;
exit;
- kernel removes unnecessary spills and fills, if called function is
inlined by verifier or current JIT (with assumption that patch
inserted by verifier or JIT honors nocsr contract, e.g. does not
scratch r3-r5 for the example above), e.g. the code above would be
transformed to:
r1 = 1;
r2 = 2;
call %[to_be_inlined]
r0 = r1;
r0 += r2;
exit;
Technically, the transformation is split into the following phases:
- function mark_nocsr_patterns(), called from bpf_check()
searches and marks potential patterns in instruction auxiliary data;
- upon stack read or write access,
function check_nocsr_stack_contract() is used to verify if
stack offsets, presumably reserved for nocsr patterns, are used
only from those patterns;
- function remove_nocsr_spills_fills(), called from bpf_check(),
applies the rewrite for valid patterns.
See comment in mark_nocsr_pattern_for_call() for more details.
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240722233844.1406874-3-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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syzbot reported a kernel crash due to
commit 1f1e864b6555 ("bpf: Handle sign-extenstin ctx member accesses").
The reason is due to sign-extension of 32-bit load for
packet data/data_end/data_meta uapi field.
The original code looks like:
r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */
r3 = *(u32 *)(r1 + 80) /* load __sk_buff->data_end */
r0 = r2
r0 += 8
if r3 > r0 goto +1
...
Note that __sk_buff->data load has 32-bit sign extension.
After verification and convert_ctx_accesses(), the final asm code looks like:
r2 = *(u64 *)(r1 +208)
r2 = (s32)r2
r3 = *(u64 *)(r1 +80)
r0 = r2
r0 += 8
if r3 > r0 goto pc+1
...
Note that 'r2 = (s32)r2' may make the kernel __sk_buff->data address invalid
which may cause runtime failure.
Currently, in C code, typically we have
void *data = (void *)(long)skb->data;
void *data_end = (void *)(long)skb->data_end;
...
and it will generate
r2 = *(u64 *)(r1 +208)
r3 = *(u64 *)(r1 +80)
r0 = r2
r0 += 8
if r3 > r0 goto pc+1
If we allow sign-extension,
void *data = (void *)(long)(int)skb->data;
void *data_end = (void *)(long)skb->data_end;
...
the generated code looks like
r2 = *(u64 *)(r1 +208)
r2 <<= 32
r2 s>>= 32
r3 = *(u64 *)(r1 +80)
r0 = r2
r0 += 8
if r3 > r0 goto pc+1
and this will cause verification failure since "r2 <<= 32" is not allowed
as "r2" is a packet pointer.
To fix this issue for case
r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */
this patch added additional checking in is_valid_access() callback
function for packet data/data_end/data_meta access. If those accesses
are with sign-extenstion, the verification will fail.
[1] https://lore.kernel.org/bpf/000000000000c90eee061d236d37@google.com/
Reported-by: syzbot+ad9ec60c8eaf69e6f99c@syzkaller.appspotmail.com
Fixes: 1f1e864b6555 ("bpf: Handle sign-extenstin ctx member accesses")
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240723153439.2429035-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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Move management of the perf_event->security blob out of the individual
security modules and into the security infrastructure. Instead of
allocating the blobs from within the modules the modules tell the
infrastructure how much space is required, and the space is allocated
there. There are no longer any modules that require the perf_event_free()
hook. The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Move management of the infiniband security blob out of the individual
security modules and into the LSM infrastructure. The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the ib_free() hook.
The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Move management of the dev_tun security blob out of the individual
security modules and into the LSM infrastructure. The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the dev_tun_free hook.
The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Move management of the key->security blob out of the individual security
modules and into the security infrastructure. Instead of allocating the
blobs from within the modules the modules tell the infrastructure how
much space is required, and the space is allocated there. There are
no existing modules that require a key_free hook, so the call to it and
the definition for it have been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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Move management of the sock->sk_security blob out
of the individual security modules and into the security
infrastructure. Instead of allocating the blobs from within
the modules the modules tell the infrastructure how much
space is required, and the space is allocated there.
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
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bpf progs can be attached to kernel functions, and the attached functions
can take different parameters or return different return values. If
prog attached to one kernel function tail calls prog attached to another
kernel function, the ctx access or return value verification could be
bypassed.
For example, if prog1 is attached to func1 which takes only 1 parameter
and prog2 is attached to func2 which takes two parameters. Since verifier
assumes the bpf ctx passed to prog2 is constructed based on func2's
prototype, verifier allows prog2 to access the second parameter from
the bpf ctx passed to it. The problem is that verifier does not prevent
prog1 from passing its bpf ctx to prog2 via tail call. In this case,
the bpf ctx passed to prog2 is constructed from func1 instead of func2,
that is, the assumption for ctx access verification is bypassed.
Another example, if BPF LSM prog1 is attached to hook file_alloc_security,
and BPF LSM prog2 is attached to hook bpf_lsm_audit_rule_known. Verifier
knows the return value rules for these two hooks, e.g. it is legal for
bpf_lsm_audit_rule_known to return positive number 1, and it is illegal
for file_alloc_security to return positive number. So verifier allows
prog2 to return positive number 1, but does not allow prog1 to return
positive number. The problem is that verifier does not prevent prog1
from calling prog2 via tail call. In this case, prog2's return value 1
will be used as the return value for prog1's hook file_alloc_security.
That is, the return value rule is bypassed.
This patch adds restriction for tail call to prevent such bypasses.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Link: https://lore.kernel.org/r/20240719110059.797546-4-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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A bpf prog returning a positive number attached to file_alloc_security
hook makes kernel panic.
This happens because file system can not filter out the positive number
returned by the LSM prog using IS_ERR, and misinterprets this positive
number as a file pointer.
Given that hook file_alloc_security never returned positive number
before the introduction of BPF LSM, and other BPF LSM hooks may
encounter similar issues, this patch adds LSM return value check
in verifier, to ensure no unexpected value is returned.
Fixes: 520b7aa00d8c ("bpf: lsm: Initialize the BPF LSM hooks")
Reported-by: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20240719110059.797546-3-xukuohai@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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The task pointer which is handed to dequeue_signal() is always current. The
argument along with the first comment about signalfd in that function is
confusing at best. Remove it and use current internally.
Update the stale comment for dequeue_signal() while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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No requirement for a real list. Spare a few bytes.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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The bpf_tcp_ca struct_ops currently uses a "u32 unsupported_ops[]"
array to track which ops is not supported.
After cfi_stubs had been added, the function pointer in cfi_stubs is
also NULL for the unsupported ops. Thus, the "u32 unsupported_ops[]"
becomes redundant. This observation was originally brought up in the
bpf/cfi discussion:
https://lore.kernel.org/bpf/CAADnVQJoEkdjyCEJRPASjBw1QGsKYrF33QdMGc1RZa9b88bAEA@mail.gmail.com/
The recent bpf qdisc patch (https://lore.kernel.org/bpf/20240714175130.4051012-6-amery.hung@bytedance.com/)
also needs to specify quite many unsupported ops. It is a good time
to clean it up.
This patch removes the need of "u32 unsupported_ops[]" and tests for null-ness
in the cfi_stubs instead.
Testing the cfi_stubs is done in a new function bpf_struct_ops_supported().
The verifier will call bpf_struct_ops_supported() when loading the
struct_ops program. The ".check_member" is removed from the bpf_tcp_ca
in this patch. ".check_member" could still be useful for other subsytems
to enforce other restrictions (e.g. sched_ext checks for prog->sleepable).
To keep the same error return, ENOTSUPP is used.
Cc: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240722183049.2254692-2-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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Pull virtio fixes from Michael Tsirkin:
"The biggest thing here is the adminq change - but it looks like the
only way to avoid headq blocking causing indefinite stalls.
This fixes three issues:
- Prevent admin commands on one VF blocking another.
This prevents a bad VF from blocking a good one, as well as fixing
a scalability issue with large # of VFs
- Correctly return error on command failure on octeon. We used to
treat failed commands as a success.
- Fix modpost warning when building virtio_dma_buf. Harmless, but the
fix is trivial"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
virtio_pci_modern: remove admin queue serialization lock
virtio_pci_modern: use completion instead of busy loop to wait on admin cmd result
virtio_pci_modern: pass cmd as an identification token
virtio_pci_modern: create admin queue of queried size
virtio: create admin queues alongside other virtqueues
virtio_pci: pass vq info as an argument to vp_setup_vq()
virtio: push out code to vp_avq_index()
virtio_pci_modern: treat vp_dev->admin_vq.info.vq pointer as static
virtio_pci: introduce vector allocation fallback for slow path virtqueues
virtio_pci: pass vector policy enum to vp_find_one_vq_msix()
virtio_pci: pass vector policy enum to vp_find_vqs_msix()
virtio_pci: simplify vp_request_msix_vectors() call a bit
virtio_pci: push out single vq find code to vp_find_one_vq_msix()
vdpa/octeon_ep: Fix error code in octep_process_mbox()
virtio: add missing MODULE_DESCRIPTION() macro
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Use bpf_verifier_state->jmp_history to track which registers were
updated by find_equal_scalars() (renamed to collect_linked_regs())
when conditional jump was verified. Use recorded information in
backtrack_insn() to propagate precision.
E.g. for the following program:
while verifying instructions
1: r1 = r0 |
2: if r1 < 8 goto ... | push r0,r1 as linked registers in jmp_history
3: if r0 > 16 goto ... | push r0,r1 as linked registers in jmp_history
4: r2 = r10 |
5: r2 += r0 v mark_chain_precision(r0)
while doing mark_chain_precision(r0)
5: r2 += r0 | mark r0 precise
4: r2 = r10 |
3: if r0 > 16 goto ... | mark r0,r1 as precise
2: if r1 < 8 goto ... | mark r0,r1 as precise
1: r1 = r0 v
Technically, do this as follows:
- Use 10 bits to identify each register that gains range because of
sync_linked_regs():
- 3 bits for frame number;
- 6 bits for register or stack slot number;
- 1 bit to indicate if register is spilled.
- Use u64 as a vector of 6 such records + 4 bits for vector length.
- Augment struct bpf_jmp_history_entry with a field 'linked_regs'
representing such vector.
- When doing check_cond_jmp_op() remember up to 6 registers that
gain range because of sync_linked_regs() in such a vector.
- Don't propagate range information and reset IDs for registers that
don't fit in 6-value vector.
- Push a pair {instruction index, linked registers vector}
to bpf_verifier_state->jmp_history.
- When doing backtrack_insn() check if any of recorded linked
registers is currently marked precise, if so mark all linked
registers as precise.
This also requires fixes for two test_verifier tests:
- precise: test 1
- precise: test 2
Both tests contain the following instruction sequence:
19: (bf) r2 = r9 ; R2=scalar(id=3) R9=scalar(id=3)
20: (a5) if r2 < 0x8 goto pc+1 ; R2=scalar(id=3,umin=8)
21: (95) exit
22: (07) r2 += 1 ; R2_w=scalar(id=3+1,...)
23: (bf) r1 = r10 ; R1_w=fp0 R10=fp0
24: (07) r1 += -8 ; R1_w=fp-8
25: (b7) r3 = 0 ; R3_w=0
26: (85) call bpf_probe_read_kernel#113
The call to bpf_probe_read_kernel() at (26) forces r2 to be precise.
Previously, this forced all registers with same id to become precise
immediately when mark_chain_precision() is called.
After this change, the precision is propagated to registers sharing
same id only when 'if' instruction is backtracked.
Hence verification log for both tests is changed:
regs=r2,r9 -> regs=r2 for instructions 25..20.
Fixes: 904e6ddf4133 ("bpf: Use scalar ids in mark_chain_precision()")
Reported-by: Hao Sun <sunhao.th@gmail.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240718202357.1746514-2-eddyz87@gmail.com
Closes: https://lore.kernel.org/bpf/CAEf4BzZ0xidVCqB47XnkXcNhkPWF6_nTV7yt+_Lf0kcFEut2Mg@mail.gmail.com/
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'masklength' is supposed to be an IIO private member. However, drivers
(often in trigger handlers) need to access it to iterate over the
enabled channels for example (there are other reasons). Hence, a couple
of new accessors are being added:
* iio_for_each_active_channel() - Iterates over the active channels;
* iio_get_masklength() - Get length of the channels mask.
The goal of these new accessors is to annotate 'masklength' as private
as soon as all drivers accessing it are converted to use the new
helpers.
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Alexandru Ardelean <aardelean@baylibre.com>
Link: https://patch.msgid.link/20240702-dev-iio-masklength-private-v1-1-98193bf536a6@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
|
|
This is the really old legacy kernel profiling code, which has long
since been obviated by "real profiling" (ie 'prof' and company), and
mainly remains as a source of syzbot reports.
There are anecdotal reports that people still use it for boot-time
profiling, but it's unlikely that such use would care about the old NUMA
optimizations in this code from 2004 (commit ad02973d42: "profile: 512x
Altix timer interrupt livelock fix" in the BK import archive at [1])
So in order to head off future syzbot reports, let's try to simplify
this code and get rid of the per-cpu profile buffers that are quite a
large portion of the complexity footprint of this thing (including CPU
hotplug callbacks etc).
It's unlikely anybody will actually notice, or possibly, as Thomas put
it: "Only people who indulge in nostalgia will notice :)".
That said, if it turns out that this code is actually actively used by
somebody, we can always revert this removal. Thus the "attempt" in the
summary line.
[ Note: in a small nod to "the profiling code can cause NUMA problems",
this also removes the "increment the last entry in the profiling array
on any unknown hits" logic. That would account any program counter in
a module to that single counter location, and might exacerbate any
NUMA cacheline bouncing issues ]
Link: https://lore.kernel.org/all/CAHk-=wgs52BxT4Zjmjz8aNvHWKxf5_ThBY4bYL1Y6CTaNL2dTw@mail.gmail.com/
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git [1]
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Various PCI controllers that mux MSIs onto a single IRQ line produce these
"IRQ%d: set affinity failed" warnings when entering suspend. This has been
discussed before [1] [2] and an example test case is included at the end of
this commit message.
Controller drivers that create MSI IRQ domain with
MSI_FLAG_USE_DEF_CHIP_OPS and do not override the .irq_set_affinity()
irqchip callback get assigned the default msi_domain_set_affinity()
callback. That is not desired on controllers where it is not possible to
set affinity of each MSI IRQ line to a specific CPU core due to hardware
limitation.
Introduce flag MSI_FLAG_NO_AFFINITY, which keeps .irq_set_affinity() unset
if the controller driver did not assign it. This way, migrate_one_irq()
can exit right away, without printing the warning. The .irq_set_affinity()
implementations which only return -EINVAL can be removed from multiple
controller drivers.
$ grep 25 /proc/interrupts
25: 0 0 0 0 0 0 0 0 PCIe MSI 0 Edge PCIe PME
$ echo core > /sys/power/pm_test ; echo mem > /sys/power/state
...
Disabling non-boot CPUs ...
IRQ25: set affinity failed(-22). <---------- This is being silenced here
psci: CPU7 killed (polled 4 ms)
...
[1] https://lore.kernel.org/all/d4a6eea3c5e33a3a4056885419df95a7@kernel.org/
[2] https://lore.kernel.org/all/5f4947b18bf381615a37aa81c2242477@kernel.org/
Link: https://lore.kernel.org/r/20240723132958.41320-2-marek.vasut+renesas@mailbox.org
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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again
When btrfs makes a block group read-only, it adds all free regions in the
block group to space_info->bytes_readonly. That free space excludes
reserved and pinned regions. OTOH, when btrfs makes the block group
read-write again, it moves all the unused regions into the block group's
zone_unusable. That unused region includes reserved and pinned regions.
As a result, it counts too much zone_unusable bytes.
Fortunately (or unfortunately), having erroneous zone_unusable does not
affect the calculation of space_info->bytes_readonly, because free
space (num_bytes in btrfs_dec_block_group_ro) calculation is done based on
the erroneous zone_unusable and it reduces the num_bytes just to cancel the
error.
This behavior can be easily discovered by adding a WARN_ON to check e.g,
"bg->pinned > 0" in btrfs_dec_block_group_ro(), and running fstests test
case like btrfs/282.
Fix it by properly considering pinned and reserved in
btrfs_dec_block_group_ro(). Also, add a WARN_ON and introduce
btrfs_space_info_update_bytes_zone_unusable() to catch a similar mistake.
Fixes: 169e0da91a21 ("btrfs: zoned: track unusable bytes for zones")
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Add clock IDs for the eARC Rx device found on sm1 SoCs
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240719093934.3985139-2-jbrunet@baylibre.com
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
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* Use simple CFS pick_task for DL pick_task
DL server's pick_task calls CFS's pick_next_task_fair(), this is wrong
because core scheduling's pick_task only calls CFS's pick_task() for
evaluation / checking of the CFS task (comparing across CPUs), not for
actually affirmatively picking the next task. This causes RB tree
corruption issues in CFS that were found by syzbot.
* Make pick_task_fair clear DL server
A DL task pick might set ->dl_server, but it is possible the task will
never run (say the other HT has a stop task). If the CFS task is picked
in the future directly (say without DL server), ->dl_server will be
set. So clear it in pick_task_fair().
This fixes the KASAN issue reported by syzbot in set_next_entity().
(DL refactoring suggestions by Vineeth Pillai).
Reported-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vineeth Pillai <vineeth@bitbyteword.org>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/b10489ab1f03d23e08e6097acea47442e7d6466f.1716811044.git.bristot@kernel.org
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Among the motivations for the DL servers is the real-time throttling
mechanism. This mechanism works by throttling the rt_rq after
running for a long period without leaving space for fair tasks.
The base dl server avoids this problem by boosting fair tasks instead
of throttling the rt_rq. The point is that it boosts without waiting
for potential starvation, causing some non-intuitive cases.
For example, an IRQ dispatches two tasks on an idle system, a fair
and an RT. The DL server will be activated, running the fair task
before the RT one. This problem can be avoided by deferring the
dl server activation.
By setting the defer option, the dl_server will dispatch an
SCHED_DEADLINE reservation with replenished runtime, but throttled.
The dl_timer will be set for the defer time at (period - runtime) ns
from start time. Thus boosting the fair rq at defer time.
If the fair scheduler has the opportunity to run while waiting
for defer time, the dl server runtime will be consumed. If
the runtime is completely consumed before the defer time, the
server will be replenished while still in a throttled state. Then,
the dl_timer will be reset to the new defer time
If the fair server reaches the defer time without consuming
its runtime, the server will start running, following CBS rules
(thus without breaking SCHED_DEADLINE). Then the server will
continue the running state (without deferring) until it fair
tasks are able to execute as regular fair scheduler (end of
the starvation).
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/r/dd175943c72533cd9f0b87767c6499204879cc38.1716811044.git.bristot@kernel.org
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Add an explanation for the newly added variable.
Fixes: 63ba8422f876 ("sched/deadline: Introduce deadline servers")
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/147f7aa8cb8fd925f36aa8059af6a35aad08b45a.1716811044.git.bristot@kernel.org
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Start a new section for AUX PMUs in hw_perf_event.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Add a new .note section containing type, size, offset and flags of every
xfeature that is present.
This information will be used by debuggers to understand the XSAVE layout of
the machine where the core file has been dumped, and to read XSAVE registers,
especially during cross-platform debugging.
The XSAVE layouts of modern AMD and Intel CPUs differ, especially since
Memory Protection Keys and the AVX-512 features have been inculcated into
the AMD CPUs.
Since AMD never adopted (and hence never left room in the XSAVE layout for)
the Intel MPX feature, tools like GDB had assumed a fixed XSAVE layout
matching that of Intel (based on the XCR0 mask).
Hence, core dumps from AMD CPUs didn't match the known size for the XCR0 mask.
This resulted in GDB and other tools not being able to access the values of
the AVX-512 and PKRU registers on AMD CPUs.
To solve this, an interim solution has been accepted into GDB, and is already
a part of GDB 14, see
https://sourceware.org/pipermail/gdb-patches/2023-March/198081.html.
But it depends on heuristics based on the total XSAVE register set size
and the XCR0 mask to infer the layouts of the various register blocks
for core dumps, and hence, is not a foolproof mechanism to determine the
layout of the XSAVE area.
Therefore, add a new core dump note in order to allow GDB/LLDB and other
relevant tools to determine the layout of the XSAVE area of the machine where
the corefile was dumped.
The new core dump note (which is being proposed as a per-process .note
section), NT_X86_XSAVE_LAYOUT (0x205) contains an array of structures.
Each structure describes an individual extended feature containing
offset, size and flags in this format:
struct x86_xfeat_component {
u32 type;
u32 size;
u32 offset;
u32 flags;
};
and in an independent manner, allowing for future extensions without depending
on hw arch specifics like CPUID etc.
[ bp: Massage commit message, zap trailing whitespace. ]
Co-developed-by: Jini Susan George <jinisusan.george@amd.com>
Signed-off-by: Jini Susan George <jinisusan.george@amd.com>
Co-developed-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Vignesh Balasubramanian <vigbalas@amd.com>
Link: https://lore.kernel.org/r/20240725161017.112111-2-vigbalas@amd.com
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In a future patch HAS_IOPORT=n will disable inb()/outb() and friends at
compile time. We thus need to #ifdef functions and their callsites which
unconditionally use these I/O accessors. In the include/video/vga.h
these are conveniently all those functions with the vga_io_* prefix.
Co-developed-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Helge Deller <deller@gmx.de>
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Backmerging to get a late RC of v6.10 before moving into v6.11.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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Add new PCI device IDs into the root IDs and miscellaneous IDs lists to
provide support for the latest generation of AMD 1Ah family 60h processor
models.
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Link: https://lore.kernel.org/r/20240722092801.3480266-1-Shyam-sundar.S-k@amd.com
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Now that we no longer have any C constant expression contexts (ie array
size declarations or static initializers) that use min() or max(), we
can simpify the implementation by not having to worry about the result
staying as a C constant expression.
So now we can unconditionally just use temporary variables of the right
type, and get rid of the excessive expansion that used to come from the
use of
__builtin_choose_expr(__is_constexpr(...), ..
to pick the specialized code for constant expressions.
Another expansion simplification is to pass the temporary variables (in
addition to the original expression) to our __types_ok() macro. That
may superficially look like it complicates the macro, but when we only
want the type of the expression, expanding the temporary variable names
is much simpler and smaller than expanding the potentially complicated
original expression.
As a result, on my machine, doing a
$ time make drivers/staging/media/atomisp/pci/isp/kernels/ynr/ynr_1.0/ia_css_ynr.host.i
goes from
real 0m16.621s
user 0m15.360s
sys 0m1.221s
to
real 0m2.532s
user 0m2.091s
sys 0m0.452s
because the token expansion goes down dramatically.
In particular, the longest line expansion (which was line 71 of that
'ia_css_ynr.host.c' file) shrinks from 23,338kB (yes, 23MB for one
single line) to "just" 1,444kB (now "only" 1.4MB).
And yes, that line is still the line from hell, because it's doing
multiple levels of "min()/max()" expansion thanks to some of them being
hidden inside the uDIGIT_FITTING() macro.
Lorenzo has a nice cleanup patch that makes that driver use inline
functions instead of macros for sDIGIT_FITTING() and uDIGIT_FITTING(),
which will fix that line once and for all, but the 16-fold reduction in
this case does show why we need to simplify these helpers.
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This state excerpt from the (de-)offloading state machine was used to
implement an ad-hoc kthread parking of rcuo kthreads. This code has
been removed and therefore the related state can be erased as well.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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RCU core can't be running anymore while in the middle of (de-)offloading
since this sort of transition now only applies to offline CPUs.
The SEGCBLIST_RCU_CORE state can therefore be removed.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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Checking for races against concurrent (de-)offloading implies the
creation of !CONFIG_RCU_NOCB_CPU stubs to check if each relevant lock
is held. For now this only implies the nocb_lock but more are to be
expected.
Create instead a NOCB specific version of RCU_LOCKDEP_WARN() to avoid
the proliferation of stubs.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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ct_rcu_watching_cpu_acquire()
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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The symbols relating to the CT_STATE part of context_tracking.state are now
all prefixed with CT_STATE.
The RCU dynticks counter part of that atomic variable still involves
symbols with different prefixes, align them all to be prefixed with
CT_RCU_WATCHING.
Suggested-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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Context tracking state related symbols currently use a mix of the
CONTEXT_ (e.g. CONTEXT_KERNEL) and CT_SATE_ (e.g. CT_STATE_MASK) prefixes.
Clean up the naming and make the ctx_state enum use the CT_STATE_ prefix.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
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Some SPI peripherals may require strict MOSI line state when the controller
is not clocking out data. Implement support for MOSI idle state
configuration (low or high) by setting the data output line level on
controller setup and after transfers. Bitbang operations now call
controller specific set_mosi_idle() callback to set MOSI to its idle state.
The MOSI line is kept at its idle state if no tx buffer is provided.
Acked-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
Link: https://patch.msgid.link/de61a600b56ed9cb714d5ea87afa88948e70041e.1720810545.git.marcelo.schmitt@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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The behavior of an SPI controller data output line (SDO or MOSI or COPI
(Controller Output Peripheral Input) for disambiguation) is usually not
specified when the controller is not clocking out data on SCLK edges.
However, there do exist SPI peripherals that require specific MOSI line
state when data is not being clocked out of the controller.
Conventional SPI controllers may set the MOSI line on SCLK edges then bring
it low when no data is going out or leave the line the state of the last
transfer bit. More elaborated controllers are capable to set the MOSI idle
state according to different configurable levels and thus are more suitable
for interfacing with demanding peripherals.
Add SPI mode bits to allow peripherals to request explicit MOSI idle state
when needed.
When supporting a particular MOSI idle configuration, the data output line
state is expected to remain at the configured level when the controller is
not clocking out data. When a device that needs a specific MOSI idle state
is identified, its driver should request the MOSI idle configuration by
setting the proper SPI mode bit.
Acked-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Tested-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
Link: https://patch.msgid.link/9802160b5e5baed7f83ee43ac819cb757a19be55.1720810545.git.marcelo.schmitt@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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The struct snd_soc_pcm_runtime has a flex array of snd_soc_component
objects at its end, and the size is kept in num_components field.
We can add __counted_by() annotation for compiler's assistance to
catch array overflows.
A slight additional change is the assignment of rtd->components[];
the array counter has to be incremented at first for avoiding
false-positive reports from compilers.
Also, the allocation size of snd_soc_pcm_runtime is cleaned up with
the standard struct_size() helper, too.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20240726155237.21961-1-tiwai@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>
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This just standardizes the use of MIN() and MAX() macros, with the very
traditional semantics. The goal is to use these for C constant
expressions and for top-level / static initializers, and so be able to
simplify the min()/max() macros.
These macro names were used by various kernel code - they are very
traditional, after all - and all such users have been fixed up, with a
few different approaches:
- trivial duplicated macro definitions have been removed
Note that 'trivial' here means that it's obviously kernel code that
already included all the major kernel headers, and thus gets the new
generic MIN/MAX macros automatically.
- non-trivial duplicated macro definitions are guarded with #ifndef
This is the "yes, they define their own versions, but no, the include
situation is not entirely obvious, and maybe they don't get the
generic version automatically" case.
- strange use case #1
A couple of drivers decided that the way they want to describe their
versioning is with
#define MAJ 1
#define MIN 2
#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)
which adds zero value and I just did my Alexander the Great
impersonation, and rewrote that pointless Gordian knot as
#define DRV_VERSION "1.2"
instead.
- strange use case #2
A couple of drivers thought that it's a good idea to have a random
'MIN' or 'MAX' define for a value or index into a table, rather than
the traditional macro that takes arguments.
These values were re-written as C enum's instead. The new
function-line macros only expand when followed by an open
parenthesis, and thus don't clash with enum use.
Happily, there weren't really all that many of these cases, and a lot of
users already had the pattern of using '#ifndef' guarding (or in one
case just using '#undef MIN') before defining their own private version
that does the same thing. I left such cases alone.
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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