On 4/26/2024 11:19 AM, Florian Fainelli wrote:
On 4/25/24 15:27, Doug Berger wrote:
The UMAC_CMD register is written from different execution
contexts and has insufficient synchronization protections to
prevent possible corruption. Of particular concern are the
acceses from the phy_device delayed work context used by the
adjust_link call and the BH context that may be used by the
ndo_set_rx_mode call.
A spinlock is added to the driver to protect contended register
accesses (i.e. reg_lock) and it is used to synchronize accesses
to UMAC_CMD.
Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
Acked-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>
As a bug fix this is totally fine. I believe there could be an
improvement made in 'net-next' whereby we introduce an
unimac_rmw_locked() or something that essentially does:
void unimac_rmw_locked(struct bcmgenet_priv *priv, u32 offset, u32
mask_clear, u32 mask_set)
{
u32 reg;
spin_lock_bh(&priv->reg_lock);
reg = bcmgenet_umac_readl(priv, offset);
reg &= ~mask_clear;
reg |= mask_set;
bcmgenet_umac_writel(priv, reg, offset);
spin_unlock_bh(&priv->reg_lock);
}
At least a couple of callers could benefit from it. Thanks!
The only issue I see is enforcing the 2us delay in reset_umac(). A
scenario where a different context might attempt to modify UMAC_CMD
during that window is admittedly contrived, but the approach of this
commit provides better protection.
-Doug
