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!)
32ba156df1
On the platform with Arch LBR, the HW raw branch type encoding may leak
to the perf tool when the SAVE_TYPE option is not set.
In the intel_pmu_store_lbr(), the HW raw branch type is stored in
lbr_entries[].type. If the SAVE_TYPE option is set, the
lbr_entries[].type will be converted into the generic PERF_BR_* type
in the intel_pmu_lbr_filter() and exposed to the user tools.
But if the SAVE_TYPE option is NOT set by the user, the current perf
kernel doesn't clear the field. The HW raw branch type leaks.
There are two solutions to fix the issue for the Arch LBR.
One is to clear the field if the SAVE_TYPE option is NOT set.
The other solution is to unconditionally convert the branch type and
expose the generic type to the user tools.
The latter is implemented here, because
- The branch type is valuable information. I don't see a case where
you would not benefit from the branch type. (Stephane Eranian)
- Not having the branch type DOES NOT save any space in the
branch record (Stephane Eranian)
- The Arch LBR HW can retrieve the common branch types from the
LBR_INFO. It doesn't require the high overhead SW disassemble.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| 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.