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net: stmmac_tc: use 64-bit arithmetic instead of 32-bit

PATCH Applied Gustavo A. R. Silva 3 participants 3 messages Jul 2, 2018 – Jul 3, 2018

Subsystems (4)
Networking Network drivers Arm STM32 stmmac Ethernet driver
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Gustavo A. R. Silva

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#0 lore raw

PATCH 1/1 net: stmmac_tc: use 64-bit arithmetic instead of 32-bit

Add suffix UL to constant 1024 in order to give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64 (64 bits, unsigned) and following expressions are currently being evaluated using 32-bit arithmetic:

qopt->idleslope * 1024 * ptr
qopt->hicredit * 1024 * 8
qopt->locredit * 1024 * 8

Addresses-Coverity-ID: 1470246 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1470248 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1470249 ("Unintentional integer overflow")

Signed-off-by Gustavo A. R. Silva <[email protected]>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c +3 -3
index 0b0fca0..8fedc28 100644
@@ -321,7 +321,7 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 	speed_div = (priv->speed == SPEED_100) ? 100000 : 1000000;
 
 	/* Final adjustments for HW */
-	value = qopt->idleslope * 1024 * ptr;
+	value = qopt->idleslope * 1024UL * ptr;
 	do_div(value, speed_div);
 	priv->plat->tx_queues_cfg[queue].idle_slope = value & GENMASK(31, 0);
 

@@ -329,10 +329,10 @@ static int tc_setup_cbs(struct stmmac_priv *priv,
 	do_div(value, speed_div);
 	priv->plat->tx_queues_cfg[queue].send_slope = value & GENMASK(31, 0);
 
-	value = qopt->hicredit * 1024 * 8;
+	value = qopt->hicredit * 1024UL * 8;
 	priv->plat->tx_queues_cfg[queue].high_credit = value & GENMASK(31, 0);
 
-	value = qopt->locredit * 1024 * 8;
+	value = qopt->locredit * 1024UL * 8;
 	priv->plat->tx_queues_cfg[queue].low_credit = value & GENMASK(31, 0);
 
 	ret = stmmac_config_cbs(priv, priv->hw,
Signature · 1 line
2.7.4
Acked-by on v1 1/1
#1 lore raw
Quoted 6 lines · Gustavo A. R. Silva

Add suffix UL to constant 1024 in order to give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64 (64 bits, unsigned) and following expressions are currently being evaluated using 32-bit arithmetic:

Quoted 9 lines

qopt->idleslope * 1024 * ptr
qopt->hicredit * 1024 * 8
qopt->locredit * 1024 * 8

Addresses-Coverity-ID: 1470246 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1470248 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1470249 ("Unintentional integer overflow")

Signed-off-by Gustavo A. R. Silva <[email protected]>
Acked-by Jose Abreu <[email protected]>

Thanks!

Best Regards,
Jose Miguel Abreu

maintainer Applied
#2 lore raw
In reply to Gustavo A. R. Silva

From: "Gustavo A. R. Silva" <[email protected]>
Date: Mon, 2 Jul 2018 07:09:32 -0500

Quoted 6 lines

Add suffix UL to constant 1024 in order to give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64 (64 bits, unsigned) and following expressions are currently being evaluated using 32-bit arithmetic:

Quoted 8 lines

qopt->idleslope * 1024 * ptr
qopt->hicredit * 1024 * 8
qopt->locredit * 1024 * 8

Addresses-Coverity-ID: 1470246 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1470248 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1470249 ("Unintentional integer overflow")

Signed-off-by Gustavo A. R. Silva <[email protected]>

Applied.