Hi Dan,
On Mon, Feb 15, 2021 at 04:00:04PM +0300, Dan Carpenter wrote:
> db->index is less than db->num_ports which 32 or less but sometimes it
> comes from the device tree so who knows.
The destination port mask is copied into a 12-bit field of the packet,
starting at bit offset 67 and ending at 56:
static inline void ocelot_ifh_set_dest(void *injection, u64 dest)
{
packing(injection, &dest, 67, 56, OCELOT_TAG_LEN, PACK, 0);
}
So this DSA tagging protocol supports at most 12 bits, which is clearly
less than 32. Attempting to send to a port number > 12 will cause the
packing() call to truncate way before there will be 32-bit truncation
due to type promotion of the BIT(port) argument towards u64.
> The ocelot_ifh_set_dest() function takes a u64 though and that
> suggests that BIT() should be changed to BIT_ULL().
I understand that you want to silence the warning, which fundamentally
comes from the packing() API which works with u64 values and nothing of
a smaller size. So I can send a patch which replaces BIT(port) with
BIT_ULL(port), even if in practice both are equally fine.
