Re: [PATCH v4 net-next 02/14] net: enetc: extract common helpers for MAC hash filter configuration

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Fallback from exact match to hash table filter programs raw MAC address bytes as the hash bitmap due to a union overlay.
--

--- Patch [2]: [PATCH v4 net-next 02/14] net: enetc: extract common helpers for MAC hash filter configuration ---
commit b257fa43e9724b5d1d7798562be99893baa1b8d9
Author: Wei Fang <wei.fang@nxp.com>

net: enetc: extract common helpers for MAC hash filter configuration
    
This commit extracts MAC hash filter configuration code into common
helper functions to share the implementation between the ENETC v1 and v4
drivers.

> diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c b/drivers/net/ethernet/freescale/enetc/enetc_pf.c
> index a97d2e2dd07b7..db2a800a7aaf0 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c

[ ... ]

> @@ -135,7 +108,7 @@ static void enetc_sync_mac_filters(struct enetc_pf *pf)
>  		if (em) {
>  			int err;
>  
> -			enetc_clear_mac_ht_flt(si, 0, UC);
> +			enetc_set_si_uc_hash_filter(si, 0, 0);
>  
>  			err = enetc_set_mac_flt_entry(si, pos, f->mac_addr,
>  						      BIT(0));
> @@ -147,11 +120,15 @@ static void enetc_sync_mac_filters(struct enetc_pf *pf)
>  				 err);
>  		}
>  
> +		bitmap_to_arr64(&hash, f->mac_hash_table,
> +				ENETC_MADDR_HASH_TBL_SZ);

[Severity: High]
This is a pre-existing issue, but I noticed a potential problem in this
fallback path when an exact match filter fails.

In struct enetc_mac_filter, mac_addr and mac_hash_table share a union:

struct enetc_mac_filter {
    union {
        char mac_addr[ETH_ALEN];
        DECLARE_BITMAP(mac_hash_table, ENETC_MADDR_HASH_TBL_SZ);
    };
    int mac_addr_cnt;
};

If enetc_set_mac_flt_entry() above fails to program the exact match filter
(where f->mac_addr is currently populated), the code logs a warning and falls
back to using the hash table filter.

Because of the union overlay, doesn't bitmap_to_arr64() end up reading the
raw MAC address bytes from the exact match attempt and incorrectly programming
them as the hardware's 64-bit hash filter?

>  		/* hash table filter, clear EM filter for UC entries */
> -		if (i == UC)
> +		if (i == UC) {
>  			enetc_clear_mac_flt_entry(si, pos);
> -
> -		enetc_set_mac_ht_flt(si, 0, i, *f->mac_hash_table);
> +			enetc_set_si_uc_hash_filter(si, 0, hash);
> +		} else {
> +			enetc_set_si_mc_hash_filter(si, 0, hash);
> +		}
>  	}
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260707081834.710730-1-wei.fang@oss.nxp.com?part=2