Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices:
OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
332ce969b7
To enable/disable kernel access to user space, the 8xx has to modify the properties of access group 1. This is done by writing predefined values into SPRN_Mx_AP registers. As of today, a __put_user() gives: 00000d64 <my_test>: d64: 3d 20 4f ff lis r9,20479 d68: 61 29 ff ff ori r9,r9,65535 d6c: 7d 3a c3 a6 mtspr 794,r9 d70: 39 20 00 00 li r9,0 d74: 90 83 00 00 stw r4,0(r3) d78: 3d 20 6f ff lis r9,28671 d7c: 61 29 ff ff ori r9,r9,65535 d80: 7d 3a c3 a6 mtspr 794,r9 d84: 4e 80 00 20 blr Because only groups 0 and 1 are used, the definition of groups 2 to 15 doesn't matter. By setting unused bits to 0 instead on 1, one instruction is removed for each lock and unlock action: 00000d5c <my_test>: d5c: 3d 20 40 00 lis r9,16384 d60: 7d 3a c3 a6 mtspr 794,r9 d64: 39 20 00 00 li r9,0 d68: 90 83 00 00 stw r4,0(r3) d6c: 3d 20 60 00 lis r9,24576 d70: 7d 3a c3 a6 mtspr 794,r9 d74: 4e 80 00 20 blr Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/57425c33dd72f292b1a23570244b81419072a7aa.1586945153.git.christophe.leroy@c-s.fr |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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 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.