Vladimir Murzin
087e96beec
[ Upstream commit2acb909750] It was observed that decompressor running on hardware implementing ARM v8.2 Load/Store Multiple Atomicity and Ordering Control (LSMAOC), say, as guest, would stuck just after: Uncompressing Linux... done, booting the kernel. The reason is that it clears nTLSMD bit when disabling caches: nTLSMD, bit [3] When ARMv8.2-LSMAOC is implemented: No Trap Load Multiple and Store Multiple to Device-nGRE/Device-nGnRE/Device-nGnRnE memory. 0b0 All memory accesses by A32 and T32 Load Multiple and Store Multiple at EL1 or EL0 that are marked at stage 1 as Device-nGRE/Device-nGnRE/Device-nGnRnE memory are trapped and generate a stage 1 Alignment fault. 0b1 All memory accesses by A32 and T32 Load Multiple and Store Multiple at EL1 or EL0 that are marked at stage 1 as Device-nGRE/Device-nGnRE/Device-nGnRnE memory are not trapped. This bit is permitted to be cached in a TLB. This field resets to 1. Otherwise: Reserved, RES1 So as effect we start getting traps we are not quite ready for. Looking into history it seems that mask used for SCTLR clear came from the similar code for ARMv4, where bit[3] is the enable/disable bit for the write buffer. That not applicable to ARMv7 and onwards, so retire that bit from the masks. Fixes:7d09e85448("[ARM] 4393/2: ARMv7: Add uncompressing code for the new CPU Id format") Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> 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.