On Google gs101, the number of UTP transfer request slots (nutrs) is
32, and in this case the driver ends up programming the UTRL_NEXUS_TYPE
incorrectly as 0.

This is because the left hand side of the shift is 1, which is of type
int, i.e. 31 bits wide. Shifting by more than that width results in
undefined behaviour.

Fix this by switching to the BIT() macro, which applies correct type
casting as required. This ensures the correct value is written to
UTRL_NEXUS_TYPE (0xffffffff on gs101), and it also fixes a UBSAN shift
warning:
    UBSAN: shift-out-of-bounds in drivers/ufs/host/ufs-exynos.c:1113:21
    shift exponent 32 is too large for 32-bit type 'int'

For consistency, apply the same change to the nutmrs / UTMRL_NEXUS_TYPE
write.

Fixes: 55f4b1f73631 ("scsi: ufs: ufs-exynos: Add UFS host support for Exynos SoCs")
Cc: stable@vger.kernel.org
Signed-off-by: André Draszik <andre.draszik@linaro.org>
---
 drivers/ufs/host/ufs-exynos.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/host/ufs-exynos.c b/drivers/ufs/host/ufs-exynos.c
index 3e545af536e53e06b66c624ed0dc6dc7de13549f..f0adcd9dd553d2e630c75e8c3220e21bc5f7c8d8 100644
--- a/drivers/ufs/host/ufs-exynos.c
+++ b/drivers/ufs/host/ufs-exynos.c
@@ -1110,8 +1110,8 @@ static int exynos_ufs_post_link(struct ufs_hba *hba)
 	hci_writel(ufs, val, HCI_TXPRDT_ENTRY_SIZE);
 
 	hci_writel(ufs, ilog2(DATA_UNIT_SIZE), HCI_RXPRDT_ENTRY_SIZE);
-	hci_writel(ufs, (1 << hba->nutrs) - 1, HCI_UTRL_NEXUS_TYPE);
-	hci_writel(ufs, (1 << hba->nutmrs) - 1, HCI_UTMRL_NEXUS_TYPE);
+	hci_writel(ufs, BIT(hba->nutrs) - 1, HCI_UTRL_NEXUS_TYPE);
+	hci_writel(ufs, BIT(hba->nutmrs) - 1, HCI_UTMRL_NEXUS_TYPE);
 	hci_writel(ufs, 0xf, HCI_AXIDMA_RWDATA_BURST_LEN);
 
 	if (ufs->opts & EXYNOS_UFS_OPT_SKIP_CONNECTION_ESTAB)

---
base-commit: 50c8770a42faf8b1c7abe93e7c114337f580a97d
change-id: 20250707-ufs-exynos-shift-b6d1084e28c4

Best regards,
-- 
André Draszik <andre.draszik@linaro.org>

On Mon, 07 Jul 2025 18:05:27 +0100, André Draszik wrote:

> On Google gs101, the number of UTP transfer request slots (nutrs) is
> 32, and in this case the driver ends up programming the UTRL_NEXUS_TYPE
> incorrectly as 0.
> 
> This is because the left hand side of the shift is 1, which is of type
> int, i.e. 31 bits wide. Shifting by more than that width results in
> undefined behaviour.
> 
> [...]

Applied to 6.17/scsi-queue, thanks!

[1/1] scsi: ufs: exynos: fix programming of HCI_UTRL_NEXUS_TYPE
      https://git.kernel.org/mkp/scsi/c/01aad16c2257

-- 
Martin K. Petersen	Oracle Linux Engineering

André,

> On Google gs101, the number of UTP transfer request slots (nutrs) is
> 32, and in this case the driver ends up programming the UTRL_NEXUS_TYPE
> incorrectly as 0.

Applied to 6.17/scsi-staging, thanks!

-- 
Martin K. Petersen

On Mon, 7 Jul 2025 at 18:05, André Draszik <andre.draszik@linaro.org> wrote:
>
> On Google gs101, the number of UTP transfer request slots (nutrs) is
> 32, and in this case the driver ends up programming the UTRL_NEXUS_TYPE
> incorrectly as 0.
>
> This is because the left hand side of the shift is 1, which is of type
> int, i.e. 31 bits wide. Shifting by more than that width results in
> undefined behaviour.
>
> Fix this by switching to the BIT() macro, which applies correct type
> casting as required. This ensures the correct value is written to
> UTRL_NEXUS_TYPE (0xffffffff on gs101), and it also fixes a UBSAN shift
> warning:
>     UBSAN: shift-out-of-bounds in drivers/ufs/host/ufs-exynos.c:1113:21
>     shift exponent 32 is too large for 32-bit type 'int'
>
> For consistency, apply the same change to the nutmrs / UTMRL_NEXUS_TYPE
> write.
>
> Fixes: 55f4b1f73631 ("scsi: ufs: ufs-exynos: Add UFS host support for Exynos SoCs")
> Cc: stable@vger.kernel.org
> Signed-off-by: André Draszik <andre.draszik@linaro.org>
> ---

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>

On 7/7/25 10:05 AM, André Draszik wrote:
> On Google gs101, the number of UTP transfer request slots (nutrs) is
> 32, and in this case the driver ends up programming the UTRL_NEXUS_TYPE
> incorrectly as 0.
> 
> This is because the left hand side of the shift is 1, which is of type
> int, i.e. 31 bits wide. Shifting by more than that width results in
> undefined behaviour.
> 
> Fix this by switching to the BIT() macro, which applies correct type
> casting as required. This ensures the correct value is written to
> UTRL_NEXUS_TYPE (0xffffffff on gs101), and it also fixes a UBSAN shift
> warning:
>      UBSAN: shift-out-of-bounds in drivers/ufs/host/ufs-exynos.c:1113:21
>      shift exponent 32 is too large for 32-bit type 'int'
> 
> For consistency, apply the same change to the nutmrs / UTMRL_NEXUS_TYPE
> write.
> 
> Fixes: 55f4b1f73631 ("scsi: ufs: ufs-exynos: Add UFS host support for Exynos SoCs")
> Cc: stable@vger.kernel.org
> Signed-off-by: André Draszik <andre.draszik@linaro.org>
> ---
>   drivers/ufs/host/ufs-exynos.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ufs/host/ufs-exynos.c b/drivers/ufs/host/ufs-exynos.c
> index 3e545af536e53e06b66c624ed0dc6dc7de13549f..f0adcd9dd553d2e630c75e8c3220e21bc5f7c8d8 100644
> --- a/drivers/ufs/host/ufs-exynos.c
> +++ b/drivers/ufs/host/ufs-exynos.c
> @@ -1110,8 +1110,8 @@ static int exynos_ufs_post_link(struct ufs_hba *hba)
>   	hci_writel(ufs, val, HCI_TXPRDT_ENTRY_SIZE);
>   
>   	hci_writel(ufs, ilog2(DATA_UNIT_SIZE), HCI_RXPRDT_ENTRY_SIZE);
> -	hci_writel(ufs, (1 << hba->nutrs) - 1, HCI_UTRL_NEXUS_TYPE);
> -	hci_writel(ufs, (1 << hba->nutmrs) - 1, HCI_UTMRL_NEXUS_TYPE);
> +	hci_writel(ufs, BIT(hba->nutrs) - 1, HCI_UTRL_NEXUS_TYPE);
> +	hci_writel(ufs, BIT(hba->nutmrs) - 1, HCI_UTMRL_NEXUS_TYPE);
>   	hci_writel(ufs, 0xf, HCI_AXIDMA_RWDATA_BURST_LEN);
>   
>   	if (ufs->opts & EXYNOS_UFS_OPT_SKIP_CONNECTION_ESTAB)

Reviewed-by: Bart Van Assche <bvanassche@acm.org>