6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefan Wahren <wahrenst@xxxxxxx> [ Upstream commit fa8ecda9876ac1e7b29257aa82af1fd0695496e2 ] The target value of scldiv is just a byte, but its calculation in fsl_lpspi_set_bitrate could be negative. So use an adequate type to store the result and avoid overflows. After that this needs range check adjustments, but this should make the code less opaque. Signed-off-by: Stefan Wahren <wahrenst@xxxxxxx> Reviewed-by: Frank Li <Frank.Li@xxxxxxx> Link: https://patch.msgid.link/20240930093056.93418-2-wahrenst@xxxxxxx Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/spi/spi-fsl-lpspi.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c index 9573b8fa4fbfc..29b9676fe43d8 100644 --- a/drivers/spi/spi-fsl-lpspi.c +++ b/drivers/spi/spi-fsl-lpspi.c @@ -315,9 +315,10 @@ static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi) static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) { struct lpspi_config config = fsl_lpspi->config; - unsigned int perclk_rate, scldiv, div; + unsigned int perclk_rate, div; u8 prescale_max; u8 prescale; + int scldiv; perclk_rate = clk_get_rate(fsl_lpspi->clk_per); prescale_max = fsl_lpspi->devtype_data->prescale_max; @@ -338,13 +339,13 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) for (prescale = 0; prescale <= prescale_max; prescale++) { scldiv = div / (1 << prescale) - 2; - if (scldiv < 256) { + if (scldiv >= 0 && scldiv < 256) { fsl_lpspi->config.prescale = prescale; break; } } - if (scldiv >= 256) + if (scldiv < 0 || scldiv >= 256) return -EINVAL; writel(scldiv | (scldiv << 8) | ((scldiv >> 1) << 16), -- 2.43.0
