mlxsw: Use size_mul() in call to struct_size()

If, for any reason, the open-coded arithmetic causes a wraparound, the
protection that `struct_size()` adds against potential integer overflows
is defeated. Fix this by hardening call to `struct_size()` with `size_mul()`.

Fixes: 2285ec872d9d ("mlxsw: spectrum_acl_bloom_filter: use struct_size() in kzalloc()")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw: spectrum_acl_bloom_filter: Add support for Spectrum-4 calculation

Spectrum-4 will calculate hash function for bloom filter differently
from the existing ASICs.

First, two hash functions will be used to calculate 16 bits result.
The final result will be combination of the two results - 6 bits which
are result of CRC-6 will be used as MSB and 10 bits which are result of
CRC-10 will be used as LSB.

Second, while in Spectrum{2,3}, there is a padding in each chunk, so the
chunks use a sequence of whole bytes, in Spectrum-4 there is no padding,
so each chunk use 20 bytes minus 2 bits, so it is necessary to align the
chunks to be without holes.

Add dedicated 'mlxsw_sp_acl_bf_ops' for Spectrum-4 and add the required
tables for CRC calculations.

All the details are documented as part of the code for future use.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: Add operations structure for bloom filter calculation

Spectrum-4 will calculate hash function for bloom filter differently from
the existing ASICs.

There are two changes:
1. Instead of using one hash function to calculate 16 bits output (CRC-16),
two functions will be used.
2. The chunks will be built differently, without padding.

As preparation for support of Spectrum-4 bloom filter, add 'ops'
structure to allow handling different calculation for different ASICs.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: spectrum_acl_bloom_filter: Rename Spectrum-2 specific objects for future use

Spectrum-4 will calculate hash function for bloom filter differently from
the existing ASICs.

There are two changes:
1. Instead of using one hash function to calculate 16 bits output (CRC-16),
two functions will be used.
2. The chunks will be built differently, without padding.

As preparation for support of Spectrum-4 bloom filter, rename CRC table
to include "sp2" prefix and "crc16", as next patch will add two additional
tables. In addition, rename all the dedicated functions and defines for
Spectrum-{2,3} to include "sp2" prefix.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: spectrum_acl_bloom_filter: Make mlxsw_sp_acl_bf_key_encode() more flexible

Spectrum-4 will calculate hash function for bloom filter differently from
the existing ASICs.

One of the changes is related to the way that the chunks will be build -
without padding.

As preparation for support of Spectrum-4 bloom filter, make
mlxsw_sp_acl_bf_key_encode() more flexible, so it will be able to use it
for Spectrum-4 as well.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: spectrum_acl_bloom_filter: Reorder functions to make the code more aesthetic

Currently, mlxsw_sp_acl_bf_rule_count_index_get() is implemented before
mlxsw_sp_acl_bf_index_get() but is used after it.

Adding a new function for Spectrum-4 would make them further apart still.
Fix by moving them around.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

mlxsw: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Tested-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw: spectrum_acl: Introduce mutex to guard Bloom Filter updates

Bloom filter is shared within multiple regions. For updates, it needs to
be guarded by a separate mutex. Do that in order to not rely on RTNL
mutex.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw: spectrum_acl: Include delta bits into hashtable key

Currently only ERP mask masked bits in key are considered for
the hashtable key. That leads to false negative collisions
and fallbacks to C-TCAM in case two keys differ only in delta bits.

Fix this by taking full encoded key as a hashtable key,
including delta bits.

Reported-by: Nir Dotan <nird@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw: spectrum_acl_bloom_filter: use struct_size() in kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
int stuff;
void *entry[];
};

instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This issue was detected with the help of Coccinelle.

Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw: spectrum_acl: Add Bloom filter handling

Spectrum-2 HW uses Bloom filter in order to skip lookups on specific
eRPs. It uses crc-16-Msbit-first calculation over a specific layout
of a rule's key fields combined with eRP ID as well as region ID.
Per potential lookup, iff the Bloom filter entry of the calculated
index is empty, then the lookup can be skipped. Hence, the mlxsw
driver should update the Bloom filter entry per each rule insertion
or deletion when rules are part of an eRP.

Add functions for adding and deleting entries in the Bloom filter.
In order to do so also add crc-16 computation based on the specific
Spectrum-2 polynomial and a function for encoding the crc-16 input
in the manner dictated by HW implementation.

Signed-off-by: Nir Dotan <nird@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

mlxsw: spectrum_acl: Introduce Bloom filter

Lay the foundations for Bloom filter handling. Introduce a new file for
Bloom filter actions.

Add struct mlxsw_sp_acl_bf to struct mlxsw_sp_acl_erp_core and initialize
the Bloom filter data structure. Also take care of proper destruction when
terminating.

Signed-off-by: Nir Dotan <nird@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>