This is a note to let you know that I've just added the patch titled
mtd: cfi_cmdset_0001: Byte swap OTP info
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mtd-cfi_cmdset_0001-byte-swap-otp-info.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 565fe150624ee77dc63a735cc1b3bff5101f38a3 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
Date: Fri, 20 Oct 2023 22:30:29 +0200
Subject: mtd: cfi_cmdset_0001: Byte swap OTP info
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
commit 565fe150624ee77dc63a735cc1b3bff5101f38a3 upstream.
Currently the offset into the device when looking for OTP
bits can go outside of the address of the MTD NOR devices,
and if that memory isn't readable, bad things happen
on the IXP4xx (added prints that illustrate the problem before
the crash):
cfi_intelext_otp_walk walk OTP on chip 0 start at reg_prot_offset 0x00000100
ixp4xx_copy_from copy from 0x00000100 to 0xc880dd78
cfi_intelext_otp_walk walk OTP on chip 0 start at reg_prot_offset 0x12000000
ixp4xx_copy_from copy from 0x12000000 to 0xc880dd78
8<--- cut here ---
Unable to handle kernel paging request at virtual address db000000
[db000000] *pgd=00000000
(...)
This happens in this case because the IXP4xx is big endian and
the 32- and 16-bit fields in the struct cfi_intelext_otpinfo are not
properly byteswapped. Compare to how the code in read_pri_intelext()
byteswaps the fields in struct cfi_pri_intelext.
Adding a small byte swapping loop for the OTP in read_pri_intelext()
and the crash goes away.
The problem went unnoticed for many years until I enabled
CONFIG_MTD_OTP on the IXP4xx as well, triggering the bug.
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Nicolas Pitre <nico@xxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Link: https://lore.kernel.org/linux-mtd/20231020-mtd-otp-byteswap-v4-1-0d132c06aa9d@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/mtd/chips/cfi_cmdset_0001.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -420,9 +420,25 @@ read_pri_intelext(struct map_info *map,
extra_size = 0;
/* Protection Register info */
- if (extp->NumProtectionFields)
+ if (extp->NumProtectionFields) {
+ struct cfi_intelext_otpinfo *otp =
+ (struct cfi_intelext_otpinfo *)&extp->extra[0];
+
extra_size += (extp->NumProtectionFields - 1) *
- sizeof(struct cfi_intelext_otpinfo);
+ sizeof(struct cfi_intelext_otpinfo);
+
+ if (extp_size >= sizeof(*extp) + extra_size) {
+ int i;
+
+ /* Do some byteswapping if necessary */
+ for (i = 0; i < extp->NumProtectionFields - 1; i++) {
+ otp->ProtRegAddr = le32_to_cpu(otp->ProtRegAddr);
+ otp->FactGroups = le16_to_cpu(otp->FactGroups);
+ otp->UserGroups = le16_to_cpu(otp->UserGroups);
+ otp++;
+ }
+ }
+ }
}
if (extp->MinorVersion >= '1') {
Patches currently in stable-queue which might be from linus.walleij@xxxxxxxxxx are
queue-5.10/mtd-cfi_cmdset_0001-byte-swap-otp-info.patch
queue-5.10/net-ethernet-cortina-handle-large-frames.patch
queue-5.10/net-ethernet-cortina-fix-mtu-max-setting.patch
queue-5.10/net-ethernet-cortina-fix-max-rx-frame-define.patch
