net: mvpp2: debugfs: remove redundant parameter check in three functions

As per the comment above debugfs_create_dir(), it is not expected to
return an error, so an extra error check is not needed.
Drop the return check of debugfs_create_dir() in
mvpp2_dbgfs_c2_entry_init(), mvpp2_dbgfs_flow_tbl_entry_init()
and mvpp2_dbgfs_cls_init().

Signed-off-by: Minjie Du <duminjie@vivo.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20230717025538.2848-1-duminjie@vivo.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: mvpp2: fix mvpp2 debugfs leak

When mvpp2 is unloaded, the driver specific debugfs directory is not
removed, which technically leads to a memory leak. However, this
directory is only created when the first device is probed, so the
hardware is present. Removing the module is only something a developer
would to when e.g. testing out changes, so the module would be
reloaded. So this memory leak is minor.

The original attempt in commit fe2c9c61f668 ("net: mvpp2: debugfs: fix
memory leak when using debugfs_lookup()") that was labelled as a memory
leak fix was not, it fixed a refcount leak, but in doing so created a
problem when the module is reloaded - the directory already exists, but
mvpp2_root is NULL, so we lose all debugfs entries. This fix has been
reverted.

This is the alternative fix, where we remove the offending directory
whenever the driver is unloaded.

Fixes: 21da57a23125 ("net: mvpp2: add a debugfs interface for the Header Parser")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Marcin Wojtas <mw@semihalf.com>
Link: https://lore.kernel.org/r/E1ofOAB-00CzkG-UO@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Revert "net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()"

This reverts commit fe2c9c61f668cde28dac2b188028c5299cedcc1e.

On Tue, Sep 13, 2022 at 05:48:58PM +0100, Russell King (Oracle) wrote:
>What happens if this is built as a module, and the module is loaded,
>binds (and creates the directory), then is removed, and then re-
>inserted? Nothing removes the old directory, so doesn't
>debugfs_create_dir() fail, resulting in subsequent failure to add
>any subsequent debugfs entries?
>
>I don't think this patch should be backported to stable trees until
>this point is addressed.

Revert until a proper fix is available as the original behavior was
better.

Cc: Marcin Wojtas <mw@semihalf.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: stable@kernel.org
Reported-by: Russell King <linux@armlinux.org.uk>
Fixes: fe2c9c61f668 ("net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20220923234736.657413-1-sashal@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: mvpp2: debugfs: fix memory leak when using debugfs_lookup()

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time. Fix this up to be much
simpler logic and only create the root debugfs directory once when the
driver is first accessed. That resolves the memory leak and makes
things more obvious as to what the intent is.

Cc: Marcin Wojtas <mw@semihalf.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: netdev@vger.kernel.org
Cc: stable <stable@kernel.org>
Fixes: 21da57a23125 ("net: mvpp2: add a debugfs interface for the Header Parser")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

mvpp2: no need to check return value of debugfs_create functions

When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Huckleberry <nhuck@google.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: Add pmap to fs dump

There was an unused variable 'mvpp2_dbgfs_prs_pmap_fops'
Added a usage consistent with other fops to dump pmap
to userspace.

Cc: clang-built-linux@googlegroups.com
Link: https://github.com/ClangBuiltLinux/linux/issues/529
Signed-off-by: Nathan Huckleberry <nhuck@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: cls: Rename the flow table macros

The Flow Table dictates what lookups will be issued for each flow type.
The lookup sequence for each flow is similar, and the index of each
lookup is computed by some macros.

There are similar mechanisms for the C2 TCAM lookups, so in order to
avoid confusion, rename the flow table index computing macros with a
common prefix.

The only difference in behaviour is that we now use the very first entry
in the flow for the RSS lookup (the first entry was previously unused).

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: Allow reading the C2 engine table from debugfs

PPv2's Classifier uses multiple engines to perform classification. So
far, only the C2 engine is used, which has a 256 entries TCAM.

So far, we only accessed the relevant entries from the C2 engines, which
are the one implementing RSS. To implement and debug ntuple
classification offload, beaing able to see the hit count for each C2
entry is helpful, so this commit moves the logic to a dedicated
directory allowing to access each entry.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: Allow reading the flow table from debugfs

The Classifier flow table is the central part of the PPv2 Classifier,
since it describes all classification steps performed for each flow.

It has 512 entries, shared between all ports, which are divided into
sequences that are pointed-to by the decoding table. Being able to see
which entries in the flow table were hit is a key point when
implementing and debugging classification offload.

This commit allows reading each flow table entry's hit count
independently, with a clear-on-read behaviour.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: Store debugfs entries data in mvpp2 struct

The current way to store the required private data needed to access
various debugfs entries is to alloc them on the fly, share them within
the entries that need to access them, and finally have one entry free
that data upon closing. This leads to hard to maintain code, and is very
error-prone.

This commit stores all debugfs related data in the same place, making
sure this is allocated only when the debugfs directory is successfully
created, so that we don't waste memory when we don't use this feature.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: cls: Make the flow definitions const

The cls_flow table represent the overall configuration of the
classifier, used to match the different traffic classes in the Parsing
and Classification engines.

This configuration is static, and applies to all PPv2 instances, we must
therefore keep it const so that no modifications of this table are
performed at runtime.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: cls: Rename MVPP2_N_FLOWS to MVPP2_N_PRS_FLOWS

The macro definition MVPP2_N_FLOWS is ambiguous because it really
represents the number of entries in the Header Parser that are used to
identify the classification flows.

Rename the macro to clearly state that we represent the number of flows
in the Header Parser.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: fix incorrect bitwise operator

The use of the | operator always leads to true, which looks rather
suspect in this case.

Fix this by using & instead.

Addresses-Coverity-ID: 1471903 ("Wrong operator used")
Fixes: dba1d918da02 ("net: mvpp2: debugfs: add entries for classifier flows")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: add classifier hit counters

The classification operations that are used for RSS make use of several
lookup tables. Having hit counters for these tables is really helpful
to determine what flows were matched by ingress traffic, and see the
path of packets among all the classifier tables.

This commit adds hit counters for the 3 tables used at the moment :

- The decoding table (also called lookup_id table), that links flows
identified by the Header Parser to the flow table.

There's one entry per flow, located at :
.../mvpp2/<controller>/flows/XX/dec_hits

Note that there are 21 flows in the decoding table, whereas there are
52 flows in the Header Parser. That's because there are several kind
of traffic that will match a given flow. Reading the hit counter from
one sub-flow will clear all hit counter that have the same flow_id.

This also applies to the flow_hits.

- The flow table, that contains all the different lookups to be
performed by the classifier for each packet of a given flow. The match
is done on the first entry of the flow sequence.

- The C2 engine entries, that are used to assign the default rx queue,
and enable or disable RSS for a given port.

There's one entry per flow, located at:
.../mvpp2/<controller>/flows/XX/flow_hits

There is one C2 entry per port, so the c2 hit counter is located at :
.../mvpp2/<controller>/ethX/c2_hits

All hit counter values are 16-bits clear-on-read values.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: add entries for classifier flows

The classifier configuration for RSS is quite complex, with several
lookup tables being used. This commit adds useful info in debugfs to
see how the different tables are configured :

Added 2 new entries in the per-port directory :

- .../eth0/default_rxq : The default rx queue on that port
- .../eth0/rss_enable : Indicates if RSS is enabled in the C2 entry

Added the 'flows' directory :

It contains one entry per sub-flow. a 'sub-flow' is a unique path from
Header Parser to the flow table. Multiple sub-flows can point to the
same 'flow' (each flow has an id from 8 to 29, which is its index in the
Lookup Id table) :

- .../flows/00/...
/01/...
...
/51/id : The flow id. There are 21 unique flows. There's one
flow per combination of the following parameters :
- L4 protocol (TCP, UDP, none)
- L3 protocol (IPv4, IPv6)
- L3 parameters (Fragmented or not)
- L2 parameters (Vlan tag presence or not)
.../type : The flow type. This is an even higher level flow,
that we manipulate with ethtool. It can be :
"udp4" "tcp4" "udp6" "tcp6" "ipv4" "ipv6" "other".
.../eth0/...
.../eth1/engine : The hash generation engine used for this
flow on the given port
.../hash_opts : The hash generation options indicating on
what data we base the hash (vlan tag, src
IP, src port, etc.)

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: debugfs: add hit counter stats for Header Parser entries

One helpful feature to help debug the Header Parser TCAM filter in PPv2
is to be able to see if the entries did match something when a packet
comes in. This can be done by using the built-in hit counter for TCAM
entries.

This commit implements reading the counter, and exposing its value on
debugfs for each filter entry.

The counter is a 16-bits clear-on-read value, located at:
.../mvpp2/<controller>/parser/XXX/hits

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: mvpp2: add a debugfs interface for the Header Parser

Marvell PPv2 Packer Header Parser has a TCAM based filter, that is not
trivial to configure and debug. Being able to dump TCAM entries from
userspace can be really helpful to help development of new features
and debug existing ones.

This commit adds a basic debugfs interface for the PPv2 driver, focusing
on TCAM related features.

<mnt>/mvpp2/ --- f2000000.ethernet
\- f4000000.ethernet --- parser --- 000 ...
| \- 001
| \- ...
| \- 255 --- ai
| \- header_data
| \- lookup_id
| \- sram
| \- valid
\- eth1 ...
\- eth2 --- mac_filter
\- parser_entries
\- vid_filter

There's one directory per PPv2 instance, named after pdev->name to make
sure names are uniques. In each of these directories, there's :

- one directory per interface on the controller, each containing :

- "mac_filter", which lists all filtered addresses for this port
(based on TCAM, not on the kernel's uc / mc lists)

- "parser_entries", which lists the indices of all valid TCAM
entries that have this port in their port map

- "vid_filter", which lists the vids allowed on this port, based on
TCAM

- one "parser" directory (the parser is common to all ports), containing :

- one directory per TCAM entry (256 of them, from 0 to 255), each
containing :

- "ai" : Contains the 1 byte Additional Info field from TCAM, and

- "header_data" : Contains the 8 bytes Header Data extracted from
the packet

- "lookup_id" : Contains the 4 bits LU_ID

- "sram" : contains the raw SRAM data, which is the result of the TCAM
lookup. This readonly at the moment.

- "valid" : Indicates if the entry is valid of not.

All entries are read-only, and everything is output in hex form.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>