c6972fb9ba
+. LOONGSON64 use 0x98xx_xxxx_xxxx_xxxx as xphys cached, instread of 0xa8xx_xxxx_xxxx_xxxx +. let CONFIG_MIPS_PGD_C0_CONTEXT depend on 64bit +. cast CAC_BASE into u64 to silence warning on MIPS32 CP0 Context has enough room for wraping pgd into its 41-bit PTEBase field. +. For XPHYS, the trick is that pgd is 4kB aligned, and the PABITS <= 53, only save 53 - 12 = 41 bits, aka : bit[63:59] | 0000 00 | bit[53:12] | 0000 0000 0000 +. for CKSEG0, only save 29 - 12 = 17 bits when switching pgd, only need to save bit[53:12] or bit[28:12] into CP0 Context's bit[63:23], see folling asm generated at run time tlbmiss_handler_setup_pgd: .set push .set noreorder dsra a2, a0, 29 move a3, a0 dins a0, zero, 29, 35 daddiu a2, a2, 4 //for CKSEG0, a2 from 0xfffffffffffffffc //into 0 movn a0, a3, a2 dsll a0, a0, 11 jr ra dmtc0 a0, CP0_CONTEXT .set pop when using it on page walking dmfc0 k0, CP0_CONTEXT dins k0, zero, 0, 23 // zero badv2 ori k0, k0, (CAC_BASE >> 53) // *prefix* with bit[63:59] drotr k0, k0, 11 // kick it in the right place Signed-off-by: Huang Pei <huangpei@loongson.cn> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
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.