Make the function ZSTD_compressSequencesAndLiterals() available in kernel
space. This will be used by Intel QAT driver.

Additionally, (1) expose the function ZSTD_CCtx_setParameter(), which is
required to set parameters before calling ZSTD_compressSequencesAndLiterals(),
(2) update the build process to include `compress/zstd_preSplit.o` and
(3) replace `asm/unaligned.h` with `linux/unaligned.h`.

Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>

naming convention: Type names should start with a Capital letter (after the prefix)

ZSTD_resetDStream() is deprecated and replaced by ZSTD_DCtx_reset().
This removes deprecation warnings from the kernel build.

This change is a no-op, see the docs suggesting this replacement.

https://github.com/facebook/zstd/blob/fcbf2fde9ac7ce1562c7b3a394350e764bcb580f/lib/zstd.h#L2655-L2663

Linux started providing intptr_t in <linux/types.h> so we no longer need
to define it here.

https://lkml.kernel.org/r/ed66b9e4-1fb7-45be-9bb9-d4bc291c691f@p183

Backport upstream fix of the assert definition. This code is currently unused, and can be enabled for testing, which is why it wasn't caught.

https://lore.kernel.org/lkml/20230129131436.1343228-1-j.neuschaefer@gmx.net/

* Fixes zstd-dll build (https://github.com/facebook/zstd/issues/3492):
- Adds pool.o and threading.o dependency to the zstd-dll target
- Moves custom allocation functions into header to avoid needing to add dependency on common.o
- Adds test target for zstd-dll
- Adds github workflow that buildis zstd-dll

Remove all Huffman functions that aren't used by zstd.

```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora -o -path ./tests/regression/data-cache -o -path ./tests/regression/cache \) -prune -o -type f); do sed -i '/Copyright .* \(Yann Collet\)\|\(Meta Platforms\)/ s/Copyright .*/Copyright (c) Meta Platforms, Inc. and affiliates./' $f; done

git checkout HEAD -- build/VS2010/libzstd-dll/libzstd-dll.rc build/VS2010/zstd/zstd.rc tests/test-license.py contrib/linux-kernel/test/include/linux/xxhash.h examples/streaming_compression_thread_pool.c lib/legacy/zstd_v0*.c lib/legacy/zstd_v0*.h
nano ./programs/windres/zstd.rc
nano ./build/VS2010/zstd/zstd.rc
nano ./build/VS2010/libzstd-dll/libzstd-dll.rc
```

Apparently it's better. Somehow.

```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora -o -path ./tests/regression/data-cache -o -path ./tests/regression/cache \) -prune -o -type f); do echo $f; sed -i 's/\-present/-2022/' $f; done

g co HEAD -- build/meson/
```

```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora -o -path ./tests/regression/data-cache -o -path ./tests/regression/cache \) -prune -o -type f);
do
  sed -i 's/\-2021/-present/' $f;
done

g co HEAD -- .github/workflows/dev-short-tests.yml # fix bad match
```

```
for f in $(find . \( -path ./.git -o -path ./tests/fuzz/corpora \) -prune -o -type f);
do
  sed -i 's/Facebook, Inc\./Meta Platforms, Inc. and affiliates./' $f;
done
```

1. Follow the scheme introduced in PR #2501 for both `zdict.h` and `zstd_errors.h`.
2. If the `*_VISIBLE` macro isn't set, but the `*_VISIBILITY` macro is, use that.
   Also make this change for `zstd.h`, since we probably shouldn't have changed
   that macro name without backward compatibility in the first place.
3. Change all references to `*_VISIBILITY` to `*_VISIBLE`.

Fixes #3359.

Instead of using packed attribute hack, just use aligned attribute. It
improves code generation on armv6 and armv7, and slightly improves code
generation on aarch64. GCC generates identical code to regular aligned
access on ARMv6 for all versions between 4.5 and trunk, except GCC 5
which is buggy and generates the same (bad) code as packed access:
https://gcc.godbolt.org/z/hq37rz7sb

Newer gcc versions were getting smart and omitting the `memset()`.
Get around this issue by outlining the `memset()` into a different
function. This test is still hacky, but it works...

Disable ASM in the kernel for now. It requires a few changes & setup to
get working. Instead of doing it in a zstd version update, I'd prefer to
package that change as a single patch, and propose it separately from
the version update. This makes the version update easier, and reduces
some risk.

The zstd_common module was added upstream in commit
https://github.com/torvalds/linux/commit/637a642f5ca5e850186bb64ac75ebb0f124b458d.

But the kernel specific code was inlined into the library. This commit
switches it to use the out of line method that we use for the other
modules.

Add a `--spdx` option to the freestanding script to prefix
files with a line like (for `.c` files):

    // SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause

or (for `.h` and `.S` files):

    /* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */

Given the style of the line to be used depends on the extension,
a simple `sed` insert command would not work.

It also skips the file if an existing SPDX line is there,
as well as raising an error if an unexpected SPDX line appears
anywhere else in the file, as well as for unexpected
file extensions.

I double-checked that all currently generated files appear
to be license as expected with:

    grep -LRF 'This source code is licensed under both the BSD-style license (found in the'  linux/lib/zstd
    grep -LRF 'LICENSE file in the root directory of this source tree) and the GPLv2 (found' linux/lib/zstd

but somebody knowledgable on the licensing of the project should
double-check this is the intended case.

Fixes: https://github.com/facebook/zstd/issues/3293


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

- As referenced by Nick Terrelln ~ the ZSTD maintainer in the linux kernel, making zstd_reset_cstream() functionally identical to ZSTD_resetCStream() would be the perfect way to fix the warning without touching any core functions or breaking other parts of the code.

Suggested-by: Nick Terrell <terrelln@fb.com>
Signed-off-by: Cyber Knight <cyberknight755@gmail.com>

- The previous patch throws the following warning:

 ../linux/lib/zstd/zstd_compress_module.c: In function ‘zstd_reset_cstream’:
../linux/lib/zstd/zstd_compress_module.c:136:34: error: enum conversion when passing argument 2 of ‘ZSTD_CCtx_reset’ is invalid in C++ [-Werror=c++-compat]
  136 |  return ZSTD_CCtx_reset(cstream, pledged_src_size);
      |                                  ^~~~~~~~~~~~~~~~
In file included from ../linux/include/linux/zstd.h:26,
                 from ../linux/lib/zstd/zstd_compress_module.c:15:
../linux/include/linux/zstd_lib.h:501:20: note: expected ‘ZSTD_ResetDirective’ {aka ‘enum <anonymous>’} but argument is of type ‘long long unsigned int’
  501 | ZSTDLIB_API size_t ZSTD_CCtx_reset(ZSTD_CCtx* cctx, ZSTD_ResetDirective reset);
      |                    ^~~~~~~~~~~~~~~
cc1: all warnings being treated as errors

Since we have a choice to either use ZSTD_CCtx_reset or ZSTD_CCtx_setPledgedSrcSize instead of ZSTD_resetCStream, let's switch to ZSTD_CCtx_setPledgedSrcSize to not have any unnecessary warns alongside the kernel build and CI test build.

Signed-off-by: Cyber Knight <cyberknight755@gmail.com>

- This fixes the below warning:

../lib/zstd/zstd_compress_module.c: In function 'zstd_reset_cstream':
../lib/zstd/zstd_compress_module.c:136:9: warning: 'ZSTD_resetCStream' is deprecated [-Wdeprecated-declarations]
  136 |         return ZSTD_resetCStream(cstream, pledged_src_size);
      |         ^~~~~~
In file included from ../include/linux/zstd.h:26,
                 from ../lib/zstd/zstd_compress_module.c:15:
../include/linux/zstd_lib.h:2277:8: note: declared here
 2277 | size_t ZSTD_resetCStream(ZSTD_CStream* zcs, unsigned long long pledgedSrcSize);
      |        ^~~~~~~~~~~~~~~~~

ZSTD_resetCstream is deprecated and zstd_CCtx_reset is suggested to use hence let's switch to it.

Signed-off-by: Cyber Knight <cyberknight755@gmail.com>

* Add `-Wa,--noexecstack` to both `ASFLAGS` and `CFLAGS`
* Pass `ASFLAGS` to `.S` compilation instead of `CFLAGS`

Fixes #3006.

To make code more expressive, add U8 and S8 typedefs

Move portability macros to `lib/common/portability_macros.h`. This file
only contains platform/feature detection (e.g. 0/1 macros). This file is
shared between C and ASM code, so it cannot include any C code.

Rename `HUF_` ASM macros to be `ZSTD_` prefixed, and move to the new
header.

Restrict `ZSTD_ASM_SUPPORTED` to `__GNUC__`, because we need the GAS
assembler.

Finally, only include the ASM code if we are actually going to use it.
This disables it on all Windows platforms, which should resolve the
problem brought up in Issue #2789.

It is no longer necessary to get good performance, there is only a small
speed difference between -O2 and -O3, so just stick to the default of
-O2. I've measured neutral compression speed and a ~3% decompression
speed loss in userspace with clang & gcc. I've also measured neutral
compression speed and a ~1% decompression speed loss in the kernel
benchmarks.

This also fixes the stack space usage on parisc. The compiler was buggy
for -O3 and used ~3KB of stack space for several functions. With -O2 the
problem is completely resolved, and stack space is back to a few hundred
bytes.

Additionally, we get a large code size win on gcc:

| Compiler | Before (Bytes) | After (Bytes) | Delta (Bytes) |
|----------|----------------|---------------|---------------|
| gcc-11   |         952754 |        738954 |       -213800 |
| clang-12 |         976290 |        938826 |        -37464 |

The optimal parser is unlikely to be used in the linux kernel in
practice. There is no reason these functions should be force inlined,
since we aren't gaining anything, and are losing build size.

| Compiler | Before (Bytes) | After (Bytes) | Delta (Bytes) |
|----------|----------------|---------------|---------------|
| gcc-11   |        1142090 |        952754 |       -189336 |
| clang-12 |        1228402 |        976290 |       -252112 |

This is a temporary solution pending the resolution of PR #2862 in the
`dev` branch.

Test the kernel build with the standard warnings enabled so that we
don't miss issues like fixed in PR #2802.

Stacked on top of PR #2802 so CI passes, so it includes the fix. But, I
won't merge until it is merged, so @solbjorn gets the credit for the
fix.

Switch to a macro `ZSTD_FALLTHROUGH;` instead of a comment. On supported
compilers this uses an attribute, otherwise it becomes a comment.

This is necessary to be compatible with clang's `-Wfall-through`, and
gcc's `-Wfall-through=2` which don't support comments. Without this the
linux build emits a bunch of warnings.

Also add a test to CI to ensure that we don't regress.

Commit a5f2c455 ("Huffman ASM") added a new ASM source file,
but it wasn't added to the kernel Makefile despite that it received
support for Huffman ASM according to the internal definitions. This
leads to undefined references, as huf_decompress.o now calls those
ASM functions.
Add it to the list of sources when building inside the kernel tree.
Kbuild can handle .S files just fine, so none additional rules
needed.

Fixes: a5f2c455 ("Huffman ASM")
Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Linux 5.15 introduces a new Kconfig option, CONFIG_WERROR, which
forces -Werror for the entire kernel.
Current in-kernel ZSTD implementation uses functions deprecated
in 1.5.0, and thus fails on -Wdeprecated-declarations.
Turn this particular error into warning to be able to build the
kernel with CONFIG_WERROR. I'm not disabling them completely to
make sure they'll be visible and [hopefully] fixed sooner or later.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Instead of calling `ZSTD_compress_advanced()` and
`ZSTD_initCStream_advanced()`, which each take a `ZSTD_parameters` by
value, use the new advanced API.

Stack usage went from 2024 -> 1944.

Correctly identify that we are GPL v2+ or BSD 3 clause, as pointed out
in issue #2663.