From: Priyanka Singh <priyanka.singh@xxxxxxx>
Fix undefined behavior caused by left-shifting a negative value in the
expression:
cap_high ^ (1 << (bad_data_bit - 32))
The variable 'bad_data_bit' ranges from 0 to 63. When 'bad_data_bit' is
less than 32, 'bad_data_bit - 32' becomes negative, and left-shifting by a
negative value in C is undefined behavior.
Fix this by combining 'cap_high' and 'cap_low' into a 64-bit variable.
Fixes: ea2eb9a8b620 ("EDAC, fsl-ddr: Separate FSL DDR driver from MPC85xx")
Signed-off-by: Priyanka Singh <priyanka.singh@xxxxxxx>
Reviewed-by: Sherry Sun <sherry.sun@xxxxxxx>
Signed-off-by: Li Yang <leoyang.li@xxxxxxx>
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
drivers/edac/fsl_ddr_edac.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/edac/fsl_ddr_edac.c b/drivers/edac/fsl_ddr_edac.c
index 7a9fb1202f1a0..846a4ba25342a 100644
--- a/drivers/edac/fsl_ddr_edac.c
+++ b/drivers/edac/fsl_ddr_edac.c
@@ -328,6 +328,9 @@ static void fsl_mc_check(struct mem_ctl_info *mci)
* TODO: Add support for 32-bit wide buses
*/
if ((err_detect & DDR_EDE_SBE) && (bus_width == 64)) {
+ u64 cap = (u64)cap_high << 32 | (u64)cap_low;
+ u32 s = syndrome;
+
sbe_ecc_decode(cap_high, cap_low, syndrome,
&bad_data_bit, &bad_ecc_bit);
@@ -338,11 +341,15 @@ static void fsl_mc_check(struct mem_ctl_info *mci)
fsl_mc_printk(mci, KERN_ERR,
"Faulty ECC bit: %d\n", bad_ecc_bit);
+ if (bad_data_bit >= 0)
+ cap ^= 1ULL << bad_data_bit;
+
+ if (bad_ecc_bit >= 0)
+ s ^= 1 << bad_ecc_bit;
+
fsl_mc_printk(mci, KERN_ERR,
"Expected Data / ECC:\t%#8.8x_%08x / %#2.2x\n",
- cap_high ^ (1 << (bad_data_bit - 32)),
- cap_low ^ (1 << bad_data_bit),
- syndrome ^ (1 << bad_ecc_bit));
+ upper_32_bits(cap), lower_32_bits(cap), s);
}
fsl_mc_printk(mci, KERN_ERR,
--
2.34.1
