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Global UUID registry, cleanup, simplification #9261

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merged 13 commits into from
Jul 5, 2024

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andyross
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@andyross andyross commented Jun 26, 2024

This is a situation where scratching an itch (trying to get a clean mapping of component "names" I could track with some topology tooling I was experimenting with) turned into a big bleeding wound. But the healing is probably worth it.

Basically SOF's UUID hygiene had broken down in a bunch of places, and the cleanup led to a global registry that should be simpler to maintain in the long term. There's lots of code motion here but no signficant behavior changes, just a new and cleaner API. Please read the commit messages carefully, but the executive summary is:

  • No more typing UUIDs into C code. All IDs are defined with unique names via SOF_DEFINE_REG_UUID(name);

  • A handful of spots where we had colliding names and (gulp) IDs have been corrected.

  • IDs are specified in a minimally complicated text file at the top of the source tree. The build time C header generation automatically validates this file so it will stay clean.

  • UUID string names (for IDs referenced by the build) are available at runtime in Zephyr builds via the pre-existing sof_uuid_entry struct, and you can enumerate over them via the Zephyr iterable sections API. XTOS builds remain compatible, but don't get the new feature. (This does have an image size cost of ~1-2k in existing firmware builds.)

  • There remain a few spots where separate components share UUIDs. These have been left in place for compatibility, though obviously they can't (and haven't been) be built into a single image. The names of those IDs have been unified, however.

Longer term the hope is that this can be unified with things like topology and manifest generation, both to prevent errors due to miscopied IDs and to simplify tooling by giving users the ability to use a plaintext name instead.

Note also that this requires a Zephyr PR to build successfully, which corrects some mistakes with "snippets" in the Intel and NXP linker scripts. Builds without them drop the runtime UUID structs into invalid or orphan addresses (which are linker warnings, but not errors) and will cause crashes at runtime: zephyrproject-rtos/zephyr#75055

Actually all that's needed is the ROM_SECTIONS PR that already merged upstream, my fixup crossed, and there's no reason not to use the variant that merged. The next Zephyr uprev (e.g. to the 3.7.0 LTS version which is mere hours from shipping) should catch this automatically

@andyross
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Heh, look at all the reviewers. Tree-wide changes add basically everyone, I guess. FWIW I don't expect this to progress that quickly, it'll likely take a while to duplicate and resolve all the CI failures I haven't run locally. And as mentioned there's a Zephyr PR that needs to merge first anyway. Please review though.

* \param uuid_name UUID symbol name declared with DECLARE_SOF_UUID() or
* DECLARE_SOF_RT_UUID().
*/
#define SOF_UUID(uuid_name) (&(uuid_name ## _ldc))
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Oops, squashme patch wasn't and got left in, will fix

@marc-hb
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marc-hb commented Jun 28, 2024

You fix "stuff breaks with changes" by maximizing software robustness and simplifying design, not by refusing to change stuff.

Very happy you're volunteering to fix all the tests and infrastructure. We need more people like you!

For a start, there is a lot that can/should be done in https://github.com/thesofproject/sof-test - which you already know since you've been using it regularly?

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marc-hb commented Jun 28, 2024

You could, in theory, stop at any one of them. But you wouldn't want to.

Yes you do for simple testing purposes. It's called "Continuous" Integration.

And many of them are treewide, large API changes that would be harder to review sequentially without context.

There are multiple levels of reviews. There is (at least):

  • the great picture
  • the tedious, line-by-line bug catching.

This giant PR successfully provides the first one. Smaller PRs solve the second one.

The sof-logger/smex tools and the .ldc formats are all dead code in
Zephyr builds.  The logging/trace macros don't emit the correct
metadata anymore, using Zephry logging instead (and I don't think they
ever did?), and the resulting .ldc files are degenerate containing
just the header and the records for component UUIDs, which nothing
uses.

Save a few milliseconds of build time and a few bytes of output, and
free up the evolution path by not having to support legacy tools.

Signed-off-by: Andy Ross <andyross@google.com>
Stumbled on this.  Too hard to fix with the existing macros and very
low priority given existing DSP architectures, but IMHO important to
note.

Also remove the spurious extra zero byte from the entity_name
initializer.  String literals are already null-terminated and string
initializers are already defined to zero-fill the trailing bytes.
This is a noop, except that it will cause the compiler to emit a
string length overflow warning one byte earlier than necessary.

Signed-off-by: Andy Ross <andyross@google.com>
@andyross andyross force-pushed the uuid-registry branch 2 times, most recently from a9d2117 to 25cd28c Compare July 4, 2024 15:19
DECLARE_SOF_UUID() and the newer DECLARE_SOF_RT_UUID() were doing
exactly the same thing.  They create a sof_uuid_entry struct to link
into the ".static_uuids" section, which is treated specially by the
linker and not included in the firmware binary.

The only difference is the "_RT_" function also create a duplicate of
that struct that lives in .rodata to which it assigns the same symbol
name as DECLARE_SOF_UUID() uses (and creates an internal "_ldc" symbol
for the hidden struct) that is usable at runtime (hence the name).

But SOF is linked with -fdata-sections, so the extra struct will be
dropped at link time anyway if unused.  And the symbol name is
identical and visible in both variants even though it's only legally
used in one.

There's no reason to carry two different APIs around, unify.

Signed-off-by: Andy Ross <andyross@google.com>
Complete the unification of the diverged UUID APIs with a big rename.
Call it "DEFINE" instead of "DECLARE" since this is in fact a C struct
definition and not just a declaration of a type or extern symbol.

Signed-off-by: Andy Ross <andyross@google.com>
Zephyr has a similar trick to the .static_uuids trick SOF had been
playing that works in a (mostly) portable way and has some nice
features like runtime FOREACH iteration.

Use that for the UUID table, allowing it to be linked in globally in
Zephyr builds in a uniform way.

Also includes some general cleanup to try to reduce the amount of
backslashery required to express the various macros.

Signed-off-by: Andy Ross <andyross@google.com>
UUIDs are defined with both a string name (used mostly just for trace
output on legacy xtos builds) and a symbol name used as a global
variable to tie the struct to e.g. component driver definitions.  And
because human beings are allowed to type them in, they have been
somewhat inconsistently defined.  Normalize them so the string name
and the symbol name match (the symbol has a "_uuid" suffix).

Some of these rules are fairly regular:

* Some of the component drivers added a "_comp" to the global symbol
  name and some didn't.  Strip the ones that included it.

* Some naming liked dashes where underscores would be present in a
  symbol name (e.g. "dw-dma" for dw_dma_uuid).  Unify the conventions
  so all name strings are valid C symbols.

* Applying those rules produces a collision between "dai" UUIDs
  defined in dai.c, dai_legacy.c and dai_zephyr.c, so the latter two
  have been renamed to "dai_legacy" and "dai_zephyr".

And in a handful of spots the code just wasn't consistent.  These
UUIDs have been manually renamed, generally trying to pick a name the
corresponds to the original string name, or to the C file that defines
them if that seems impractical:

    Orig. String Name      Orig. Symbol     New Unified Name
    =================      ============     ================
    Maxim DSM              smart_amp        maxim_dsm
    Passthru Amp           smart_amp        passthru_smart_amp
    agent_work             agent_work_task  agent_work
    cadence_codec          cadence          cadence_codec
    channel_map            chmap            chmap
    comp_task              idc_comp_task    idc_comp
    component              comp             component
    dp_schedule            dp_sched         dp_sched
    dts_codec              dts              dts
    edf_schedule           edf_sched        edf_sched
    google_hotword_detect  ghd              google_hotword
    ipcgw                  ipcgtw           ipcgw
    irq_818x               irq_mt818x       irq_mt818x
    kd_test                keyword          keyword
    ll_schedule            ll_sched         ll_sched
    memory                 mem              mem
    micfil_dai             micfil           micfil
    mix_in                 mixin            mixin
    mix_out                mixout           mixout
    modules                intel            modules
    passthrough_codec      passthrough      passthrough
    pga                    volume           volume
    posix_ipc_task         ipc_task         ipc_task
    schedule               sch              schedule
    spi_completion         spi_compl_task   spi_completion
    waves_codec            waves            waves
    zll_schedule           zll_sched        zll_sched

Signed-off-by: Andy Ross <andyross@google.com>
If UUIDs are by definition unique, then the stored names that refer to
them must also be unique (otherwise there's no value in trying to
assign unique identifiers to them in the first place).  Fix this up by
changing names (not IDs) where needed.

The common antipatterns here are:

1. Cut-and-paste copies of drivers where the UUID values themselves
   were changed for the new driver but the code around them was not.
   These are resolved by including the platform/variant name in the
   UUID name.

2. Variant UUIDs for IPC3/IPC4 builds.  The reason isn't clear to me,
   but some drivers build with different UUID values depending on the
   build-time protocol configuration.  But these then name themselves
   identically, producing a collision.  Resolved by putting a "4"
   suffix on the IPC4 symbol name.

Signed-off-by: Andy Ross <andyross@google.com>
In a few cases we have multiple component code trying to reuse the
same UUID value for differing purposes and with different names.  But
we can resolve that by sharing names rather than changing a permanent
UUID assignment:

* Post-name-normalization, the "dai-legacy" and "dai-zephyr"
  components share a single UUID with different names (they both used
  to be "dai"), AND with the trace context of another "dai" that has a
  different (!)  ID value in src/lib.  Fix this by using a single UUID
  for the former two that collide, and renaming the latter "dai_lib".

* A single UUID got cut/pasted between the irq drivers of mt8195, imx
  "irqsteer" and imx "generic".  Since these will never be used in a
  single image, give them all the single name "interrupt" and let them
  share the UUID value.

Signed-off-by: Andy Ross <andyross@google.com>
The library code edf_sched and ll_sched_lib components were generated
with UUIDs that collide with the core EDF scheduler component, which
is illegal.  This is test code though and doesn't need to match
external artifacts, so just renumber.

Signed-off-by: Andy Ross <andyross@google.com>
This DAI driver got labelled with the same UUID as the "hsdai"
component, which is illegal.  Generate a new UUID.

This is relatively safe, as DAIs are fixed with hardware and don't get
referenced by ID in external topology.  Still frustrating to have to
do.

Signed-off-by: Andy Ross <andyross@google.com>
These two drivers both got cloned UUIDs from the acp_hs component,
which is illegal.

Renumber them.  This is relatively safe, as clock and DMA drivers are
specific to a platform and not referenced via external files like
topology.

Signed-off-by: Andy Ross <andyross@google.com>
Add a very simple uuid-registry.txt file containing all known UUIDs in
the tree, use it to generate a C header (the script validates it in
the process) that can then be used for a simplified
SOF_DEFINE_REG_UUID() mechanism that avoids the risk and temptation
temptation of components incorrectly implementing UUIDs.

The intent is that in the longer term, this file can be used by other
downstream tooling (manifest and topology generation) to more easily
reference known IDs by name in a way that avoids duplication and
error.

Signed-off-by: Andy Ross <andyross@google.com>
Strip out all the literall UUID management from existing C code (the
API itself still works for any out-of-tree or test code users) and
exclusively use the new, much simpler, SOF_DEFINE_REG_UUID() macro
which sources IDs from the registry by name.

Signed-off-by: Andy Ross <andyross@google.com>
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andyross commented Jul 4, 2024

Rebased. One more separate-toplevel-cmake spot for sof-logger needed. Cleaned up some of the checkpatch warnings. CI looked good otherwise as of the last update. Removing draft status.

@andyross andyross marked this pull request as ready for review July 4, 2024 15:52
@lgirdwood lgirdwood merged commit 17f46a7 into thesofproject:main Jul 5, 2024
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@lgirdwood
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Merging due to large surface area of string changes to reduce conflicts.

@andyross
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andyross commented Jul 5, 2024

Wow, that was fast. Will push a cleanup patch to sof-test that removes the final error (which is by-design now), maybe in combination with some more logging cleanup to more firmly wall off the old dma-trace code from Zephyr builds such that they don't need the (ignored) trace-context UUIDs in core at all.

@lyakh
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lyakh commented Jul 8, 2024

Wow, that was fast. Will push a cleanup patch to sof-test that removes the final error (which is by-design now), maybe in combination with some more logging cleanup to more firmly wall off the old dma-trace code from Zephyr builds such that they don't need the (ignored) trace-context UUIDs in core at all.

@andyross please also add support for LLEXT UUIDs

@lgirdwood
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Wow, that was fast. Will push a cleanup patch to sof-test that removes the final error (which is by-design now), maybe in combination with some more logging cleanup to more firmly wall off the old dma-trace code from Zephyr builds such that they don't need the (ignored) trace-context UUIDs in core at all.

@andyross please also add support for LLEXT UUIDs

Thanks @andyross - yeah, lets deal with the final error as the next step and follow up with llext and more cleanup.

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6 participants