sfc: Fix oops in register dump after mapping change

Commit 747df2258b1b9a2e25929ef496262c339c380009 ('sfc: Always map MCDI
shared memory as uncacheable') introduced a separate mapping for the
MCDI shared memory (MC_TREG_SMEM).  This means we can no longer easily
include it in the register dump.  Since it is not particularly useful
in debugging, substitute a recognisable dummy value.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/net/sfc/nic.c b/drivers/net/sfc/nic.c
index 10f1cb79c147..9b29a8d7c449 100644
--- a/drivers/net/sfc/nic.c
+++ b/drivers/net/sfc/nic.c
@@ -1937,6 +1937,13 @@ void efx_nic_get_regs(struct efx_nic *efx, void *buf)
 
                 size = min_t(size_t, table->step, 16);
 
+                if (table->offset >= efx->type->mem_map_size) {
+                        /* No longer mapped; return dummy data */
+                        memcpy(buf, "\xde\xc0\xad\xde", 4);
+                        buf += table->rows * size;
+                        continue;
+                }
+
                 for (i = 0; i < table->rows; i++) {
                         switch (table->step) {
                         case 4: /* 32-bit register or SRAM */