diff options
| author | Nathan Chancellor <nathan@kernel.org> | 2025-10-15 11:43:09 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-10-22 10:58:32 +0200 |
| commit | 93741bd104ce07a790519ecee3a331ee7cf61ae3 (patch) | |
| tree | 234a7c6253f778291c1410d2d0f307e151169d34 /drivers/usb | |
| parent | 832c8d3fce77cf03cc225fc555c1bffa1c547ba1 (diff) | |
| download | tip-93741bd104ce07a790519ecee3a331ee7cf61ae3.tar.gz | |
usb: uhci: Work around bogus clang shift overflow warning from DMA_BIT_MASK(64)
After commit 18a9ec886d32 ("usb: uhci: Add Aspeed AST2700 support"),
clang incorrectly warns:
In file included from drivers/usb/host/uhci-hcd.c:855:
drivers/usb/host/uhci-platform.c:69:32: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
69 | static const u64 dma_mask_64 = DMA_BIT_MASK(64);
| ^~~~~~~~~~~~~~~~
include/linux/dma-mapping.h:93:54: note: expanded from macro 'DMA_BIT_MASK'
93 | #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
| ^ ~~~
clang has a long outstanding and complicated problem [1] with generating
a proper control flow graph at global scope, resulting in it being
unable to understand that this shift can never happen due to the
'n == 64' check.
Restructure the code to only use DMA_BIT_MASK() within
uhci_hcd_platform_probe() (i.e., function scope) to avoid this global
scope issue, similar to the approach of commit 274f2232a94f ("usb: ehci:
Add Aspeed AST2700 support").
Closes: https://github.com/ClangBuiltLinux/linux/issues/2136
Link: https://github.com/ClangBuiltLinux/linux/issues/92 [1]
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Ryan Chen <ryan_chen@aspeedtech.com>
Link: https://patch.msgid.link/20251015-usb-uhci-avoid-bogus-clang-shift-warning-v2-1-68532d2f6114@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/host/uhci-platform.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/drivers/usb/host/uhci-platform.c b/drivers/usb/host/uhci-platform.c index 37607f985cc012..5e02f2ceafb6ee 100644 --- a/drivers/usb/host/uhci-platform.c +++ b/drivers/usb/host/uhci-platform.c @@ -65,13 +65,10 @@ static const struct hc_driver uhci_platform_hc_driver = { .hub_control = uhci_hub_control, }; -static const u64 dma_mask_32 = DMA_BIT_MASK(32); -static const u64 dma_mask_64 = DMA_BIT_MASK(64); - static int uhci_hcd_platform_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; - const u64 *dma_mask_ptr; + bool dma_mask_64 = false; struct usb_hcd *hcd; struct uhci_hcd *uhci; struct resource *res; @@ -85,11 +82,11 @@ static int uhci_hcd_platform_probe(struct platform_device *pdev) * Since shared usb code relies on it, set it here for now. * Once we have dma capability bindings this can go away. */ - dma_mask_ptr = (u64 *)of_device_get_match_data(&pdev->dev); - if (!dma_mask_ptr) - dma_mask_ptr = &dma_mask_32; + if (of_device_get_match_data(&pdev->dev)) + dma_mask_64 = true; - ret = dma_coerce_mask_and_coherent(&pdev->dev, *dma_mask_ptr); + ret = dma_coerce_mask_and_coherent(&pdev->dev, + dma_mask_64 ? DMA_BIT_MASK(64) : DMA_BIT_MASK(32)); if (ret) return ret; @@ -200,7 +197,7 @@ static void uhci_hcd_platform_shutdown(struct platform_device *op) static const struct of_device_id platform_uhci_ids[] = { { .compatible = "generic-uhci", }, { .compatible = "platform-uhci", }, - { .compatible = "aspeed,ast2700-uhci", .data = &dma_mask_64}, + { .compatible = "aspeed,ast2700-uhci", .data = (void *)1 }, {} }; MODULE_DEVICE_TABLE(of, platform_uhci_ids); |