Messages in this thread Patch in this message |  | | From | Guodong Xu <> | | Date | Tue, 05 May 2026 09:53:34 -0400 | | Subject | [PATCH] spi: spacemit: add u64 cast to NSEC_PER_SEC to avoid 32-bit overflow |
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NSEC_PER_SEC expands to the long constant 1000000000L, so NSEC_PER_SEC * BITS_PER_BYTE (8 * 10^9) overflows on 32-bit-long architectures before the result reaches the u64 nsec_per_word.
Promote the multiplication to u64 by casting the first operand, which is NSEC_PER_SEC.
Fixes: efcd8b9d1111 ("spi: spacemit: introduce SpacemiT K1 SPI controller driver") Suggested-by: Alex Elder <elder@riscstar.com> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202605050437.RS6mmV2b-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202605050317.Tf9j487w-lkp@intel.com/ Signed-off-by: Guodong Xu <guodong@riscstar.com> --- Hi, Mark
This is an incremental fix on top of your for-7.2, addressing the overflow warning.
Verified on BPI-F3 with a GD25Q64E SPI NOR, read/write/erase still work.
Thank you. Guodong --- drivers/spi/spi-spacemit-k1.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/spi/spi-spacemit-k1.c b/drivers/spi/spi-spacemit-k1.c index 99db429db0b26..215fe66d27b4d 100644 --- a/drivers/spi/spi-spacemit-k1.c +++ b/drivers/spi/spi-spacemit-k1.c @@ -390,7 +390,7 @@ static int k1_spi_set_speed(struct k1_spi_driver_data *drv_data, * ticks_per_word = BITS_PER_BYTE * drv_data->bytes; * We do the divide last for better accuracy. */ - nsec_per_word = NSEC_PER_SEC * BITS_PER_BYTE * drv_data->bytes; + nsec_per_word = (u64)NSEC_PER_SEC * BITS_PER_BYTE * drv_data->bytes; nsec_per_word = DIV_ROUND_UP_ULL(nsec_per_word, drv_data->rate); /* --- base-commit: efcd8b9d111177d48c841d09beca43b15d5b9e5f change-id: 20260505-spi-spacemit-k1-fix-overflow-8799dbc2ae97 Best regards, -- Guodong Xu <guodong@riscstar.com>
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