Linux kernel source tree
825c78e6a6
RISC-V distinguishes between memory accesses and device I/O and uses FENCE instruction to order them as viewed by other RISC-V harts and external devices or coprocessors. The FENCE instruction can order any combination of device input(I), device output(O), memory reads(R) and memory writes(W). For example, 'fence w, o' is used to ensure all memory writes from instructions preceding the FENCE instruction appear earlier in the global memory order than device output writes from instructions after the FENCE instruction. RISC-V issues IPIs by writing to the IMSIC/ACLINT MMIO registers, which is regarded as device output operation. However, the existing implementation of the IMSIC/ACLINT drivers issue the IPI via writel_relaxed(), which does not guarantee the order of device output operation and preceding memory writes. As a consequence the hart receiving the IPI might not observe the IPI related data. Fix this by replacing writel_relaxed() with writel() when issuing IPIs, which uses 'fence w, o' to ensure all previous writes made by the current hart are visible to other harts before they receive the IPI. Signed-off-by: Xu Lu <luxu.kernel@bytedance.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250127093846.98625-1-luxu.kernel@bytedance.com |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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 reStructuredText 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.