2020-08-13 14:40:20

by Christophe Leroy

Subject: [PATCH] sfc_ef100: Fix build failure on powerpc

ppc6xx_defconfig fails building sfc.ko module, complaining
about the lack of _umoddi3 symbol.

This is due to the following test

if (EFX_MIN_DMAQ_SIZE % reader->value) {

Because reader->value is u64.

As EFX_MIN_DMAQ_SIZE value is 512, reader->value is obviously small
enough for an u32 calculation, so cast it as (u32) for the test, to
avoid the need for _umoddi3.

Fixes: adcfc3482fff ("sfc_ef100: read Design Parameters at probe time")
Signed-off-by: Christophe Leroy <[email protected]>
---
drivers/net/ethernet/sfc/ef100_nic.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/sfc/ef100_nic.c b/drivers/net/ethernet/sfc/ef100_nic.c
index 36598d0542ed..234400b69b07 100644
--- a/drivers/net/ethernet/sfc/ef100_nic.c
+++ b/drivers/net/ethernet/sfc/ef100_nic.c
@@ -979,7 +979,7 @@ static int ef100_process_design_param(struct efx_nic *efx,
* EFX_MIN_DMAQ_SIZE is divisible by GRANULARITY.
* This is very unlikely to fail.
*/
- if (EFX_MIN_DMAQ_SIZE % reader->value) {
+ if (EFX_MIN_DMAQ_SIZE % (u32)reader->value) {
netif_err(efx, probe, efx->net_dev,
"%s size granularity is %llu, can't guarantee safety\n",
reader->type == ESE_EF100_DP_GZ_RXQ_SIZE_GRANULARITY ? "RXQ" : "TXQ",
--
2.25.0

2020-08-13 14:59:14

by Edward Cree

Subject: Re: [PATCH] sfc_ef100: Fix build failure on powerpc

On 13/08/2020 15:39, Christophe Leroy wrote:
> ppc6xx_defconfig fails building sfc.ko module, complaining
> about the lack of _umoddi3 symbol.
>
> This is due to the following test
>
> if (EFX_MIN_DMAQ_SIZE % reader->value) {
>
> Because reader->value is u64.
Already fixed in net.git by 41077c990266 ("sfc: fix ef100 design-param checking").
But thanks anyway.

2020-08-13 15:58:56

by Segher Boessenkool

Subject: Re: [PATCH] sfc_ef100: Fix build failure on powerpc

On Thu, Aug 13, 2020 at 02:39:10PM +0000, Christophe Leroy wrote:
> ppc6xx_defconfig fails building sfc.ko module, complaining
> about the lack of _umoddi3 symbol.
>
> This is due to the following test
>
> if (EFX_MIN_DMAQ_SIZE % reader->value) {
>
> Because reader->value is u64.
>
> As EFX_MIN_DMAQ_SIZE value is 512, reader->value is obviously small
> enough for an u32 calculation, so cast it as (u32) for the test, to
> avoid the need for _umoddi3.

That isn't the same e.g. if reader->value is 2**32 + small. Which
probably cannot happen, but :-)


Segher