On 04-02-2025 21:06, Thierry Reding wrote:
On Thu, Jan 16, 2025 at 09:50:32PM +0530, Mohan Kumar D wrote:
Kernel test robot reported the build errors on 32-bit platforms due to
plain 64-by-32 division. Following build erros were reported.
"ERROR: modpost: "__udivdi3" [drivers/dma/tegra210-adma.ko] undefined!
ld: drivers/dma/tegra210-adma.o: in function `tegra_adma_probe':
tegra210-adma.c:(.text+0x12cf): undefined reference to `__udivdi3'"
This can be fixed by using lower_32_bits() for the adma address space as
the offset is constrained to the lower 32 bits
Fixes: 68811c928f88 ("dmaengine: tegra210-adma: Support channel page")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-kbuild-all/202412250204.GCQhdKe3-lkp@xxxxxxxxx/
Signed-off-by: Mohan Kumar D <mkumard@xxxxxxxxxx>
---
drivers/dma/tegra210-adma.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
index 6896da8ac7ef..258220c9cb50 100644
--- a/drivers/dma/tegra210-adma.c
+++ b/drivers/dma/tegra210-adma.c
@@ -887,7 +887,8 @@ static int tegra_adma_probe(struct platform_device *pdev)
const struct tegra_adma_chip_data *cdata;
struct tegra_adma *tdma;
struct resource *res_page, *res_base;
- int ret, i, page_no;
+ unsigned int page_no, page_offset;
+ int ret, i;
cdata = of_device_get_match_data(&pdev->dev);
if (!cdata) {
@@ -914,9 +915,16 @@ static int tegra_adma_probe(struct platform_device *pdev)
res_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "global");
if (res_base) {
- page_no = (res_page->start - res_base->start) / cdata->ch_base_offset;
- if (page_no <= 0)
+ if (WARN_ON(lower_32_bits(res_page->start) <=
+ lower_32_bits(res_base->start)))
Don't we technically also want to check that
res_page->start <= res_base->start
because otherwise people might put in something that's completely out of
range? I guess maybe you could argue that the DT is then just broken,
but since we're checking anyway, might as well check for all corner
cases.
Thierry
ADMA Address range for all Tegra chip falls within 32bit range. Do you
think still we need to have this extra check which seems like redundant
for now.
+ return -EINVAL;
+
+ page_offset = lower_32_bits(res_page->start) -
+ lower_32_bits(res_base->start);
+ page_no = page_offset / cdata->ch_base_offset;
+ if (page_no == 0)
return -EINVAL;
+
tdma->ch_page_no = page_no - 1;
tdma->base_addr = devm_ioremap_resource(&pdev->dev, res_base);
if (IS_ERR(tdma->base_addr))
--
2.25.1
