6.6-stable review patch. If anyone has any objections, please let me know.
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From: Priyanka Singh priyanka.singh@nxp.com
[ Upstream commit 9ec22ac4fe766c6abba845290d5139a3fbe0153b ]
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 it 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.
[ bp: Massage commit message, simplify error bits handling. ]
Fixes: ea2eb9a8b620 ("EDAC, fsl-ddr: Separate FSL DDR driver from MPC85xx") Signed-off-by: Priyanka Singh priyanka.singh@nxp.com Signed-off-by: Li Yang leoyang.li@nxp.com Signed-off-by: Frank Li Frank.Li@nxp.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Link: https://lore.kernel.org/r/20241016-imx95_edac-v3-3-86ae6fc2756a@nxp.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/edac/fsl_ddr_edac.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/edac/fsl_ddr_edac.c b/drivers/edac/fsl_ddr_edac.c index b81757555a8a9..7809427c2dbeb 100644 --- a/drivers/edac/fsl_ddr_edac.c +++ b/drivers/edac/fsl_ddr_edac.c @@ -328,21 +328,25 @@ 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 | cap_low; + u32 s = syndrome; + sbe_ecc_decode(cap_high, cap_low, syndrome, &bad_data_bit, &bad_ecc_bit);
- if (bad_data_bit != -1) - fsl_mc_printk(mci, KERN_ERR, - "Faulty Data bit: %d\n", bad_data_bit); - if (bad_ecc_bit != -1) - fsl_mc_printk(mci, KERN_ERR, - "Faulty ECC bit: %d\n", bad_ecc_bit); + if (bad_data_bit >= 0) { + fsl_mc_printk(mci, KERN_ERR, "Faulty Data bit: %d\n", bad_data_bit); + cap ^= 1ULL << bad_data_bit; + } + + if (bad_ecc_bit >= 0) { + fsl_mc_printk(mci, KERN_ERR, "Faulty ECC bit: %d\n", bad_ecc_bit); + 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,