[PATCH v1] EDAC/bluefield - fix potential integer overflow

[David Thompson]

The 64-bit argument for the "get DIMM info" SMC call consists of
"mem_ctrl_idx" left-shifted 16 bits and OR-ed with DIMM index.
With "mem_ctrl_idx" defined as 32-bits wide the left-shift operation
truncates the upper 16 bits of information during the calculation
of the SMC argument. The "mem_ctrl_idx" stack variable must be
defined as 64-bits wide to prevent any potential integer overflow,
i.e. loss of data from upper 16 bits.

Fixes: 82413e562ea6 ("EDAC, mellanox: Add ECC support for BlueField DDR4")
Reviewed-by: Shravan Kumar Ramani <shravankr@xxxxxxxxxx>
Signed-off-by: David Thompson <davthompson@xxxxxxxxxx>
---
 drivers/edac/bluefield_edac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/edac/bluefield_edac.c b/drivers/edac/bluefield_edac.c
index 5b3164560648..0e539c107351 100644
--- a/drivers/edac/bluefield_edac.c
+++ b/drivers/edac/bluefield_edac.c
@@ -180,7 +180,7 @@ static void bluefield_edac_check(struct mem_ctl_info *mci)
 static void bluefield_edac_init_dimms(struct mem_ctl_info *mci)
 {
 	struct bluefield_edac_priv *priv = mci->pvt_info;
-	int mem_ctrl_idx = mci->mc_idx;
+	u64 mem_ctrl_idx = mci->mc_idx;
 	struct dimm_info *dimm;
 	u64 smc_info, smc_arg;
 	int is_empty = 1, i;
-- 
2.30.1