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[ Upstream commit 0b15394475e3bcaf35ca4bf22fc55d56df67224e ] Testing has shown, that when using mainline U-Boot on MT7688 based boards, the system may hang or crash while mounting the root-fs. The main issue here is that mainline U-Boot configures EBase to a value near the end of system memory. And with CONFIG_CPU_MIPSR2_IRQ_VI disabled, trap_init() will not allocate a new area to place the exception handler. The original value will be used and the handler will be copied to this location, which might already be used by some userspace application. The MT7688 supports VI - its config3 register is 0x00002420, so VInt (Bit 5) is set. But without setting CONFIG_CPU_MIPSR2_IRQ_VI this bit will not be evaluated to result in "cpu_has_vi" being set. This patch now selects CONFIG_CPU_MIPSR2_IRQ_VI on MT7620/8 which results trap_init() to allocate some memory for the exception handler. Please note that this issue was not seen with the Mediatek U-Boot version, as it does not touch EBase (stays at default of 0x8000.0000). This is strictly also not correct as the kernel (_text) resides here. Signed-off-by: Stefan Roese <sr@denx.de> [paul.burton@mips.com: s/beeing/being/] Signed-off-by: Paul Burton <paul.burton@mips.com> Cc: John Crispin <blogic@openwrt.org> Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.