mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-01-17 02:15:57 +00:00
138d73b627
The Qualcomm QSPI driver appears to require that any reads using DMA
are a mutliple of 4 bytes. If this isn't true then the controller will
clobber any extra bytes in memory following the last word. Let's
detect this and falback to PIO.
This fixes problems reported by slub_debug=FZPUA, which would complain
about "kmalloc Redzone overwritten". One such instance said:
0xffffff80c29d541a-0xffffff80c29d541b @offset=21530. First byte 0x0 instead of 0xcc
Allocated in mtd_kmalloc_up_to+0x98/0xac age=36 cpu=3 pid=6658
Tracing through what was happening I saw that, while we often did DMA
tranfers of 0x1000 bytes, sometimes we'd end up doing ones of 0x41a
bytes. Those 0x41a byte transfers were the problem.
NOTE: a future change will enable the SPI "mem ops" to help avoid this
case, but it still seems good to add the extra check in the transfer.
Fixes: b5762d95607e ("spi: spi-qcom-qspi: Add DMA mode support")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20230725110226.1.Ia2f980fc7cd0b831e633391f0bb1272914d8f381@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.