From: Colin Ian King colin.king@canonical.com
[ Upstream commit dc9e47160626cdb58d5c39a4f43dcfdb27a5c004 ]
Shifting a u8 by 24 will cause the value to be promoted to an integer. If the top bit of the u8 is set then the following conversion to an unsigned long will sign extend the value causing the upper 32 bits to be set in the result.
Fix this by casting the u8 value to an unsigned long before the shift.
Detected by CoverityScan, CID#144925-144928 ("Unintended sign extension")
Fixes: 008b30408c40 ("mfd: Add rtc support to 88pm860x") Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/rtc/rtc-88pm860x.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/rtc/rtc-88pm860x.c b/drivers/rtc/rtc-88pm860x.c index fbcf13bbbd8d..73697e4b18a9 100644 --- a/drivers/rtc/rtc-88pm860x.c +++ b/drivers/rtc/rtc-88pm860x.c @@ -115,11 +115,13 @@ static int pm860x_rtc_read_time(struct device *dev, struct rtc_time *tm) pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf); dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]); - base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7]; + base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) | + (buf[5] << 8) | buf[7];
/* load 32-bit read-only counter */ pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; ticks = base + data; dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); @@ -145,7 +147,8 @@ static int pm860x_rtc_set_time(struct device *dev, struct rtc_time *tm)
/* load 32-bit read-only counter */ pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; base = ticks - data; dev_dbg(info->dev, "set base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); @@ -170,10 +173,12 @@ static int pm860x_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf); dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]); - base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7]; + base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) | + (buf[5] << 8) | buf[7];
pm860x_bulk_read(info->i2c, PM8607_RTC_EXPIRE1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; ticks = base + data; dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks); @@ -198,11 +203,13 @@ static int pm860x_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) pm860x_page_bulk_read(info->i2c, REG0_ADDR, 8, buf); dev_dbg(info->dev, "%x-%x-%x-%x-%x-%x-%x-%x\n", buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7]); - base = (buf[1] << 24) | (buf[3] << 16) | (buf[5] << 8) | buf[7]; + base = ((unsigned long)buf[1] << 24) | (buf[3] << 16) | + (buf[5] << 8) | buf[7];
/* load 32-bit read-only counter */ pm860x_bulk_read(info->i2c, PM8607_RTC_COUNTER1, 4, buf); - data = (buf[3] << 24) | (buf[2] << 16) | (buf[1] << 8) | buf[0]; + data = ((unsigned long)buf[3] << 24) | (buf[2] << 16) | + (buf[1] << 8) | buf[0]; ticks = base + data; dev_dbg(info->dev, "get base:0x%lx, RO count:0x%lx, ticks:0x%lx\n", base, data, ticks);