0300a92e96
Currently in some cases, when the sampled instruction address register
latches to a specific address during sampling, the privilege bits
captured in the sampled event register are incorrect.
For example, a snippet from the perf report on a power10 system is:
Overhead Address Command Shared Object Symbol
........ .................. ............ ................. .......................
2.41% 0x7fff9f94a02c null_syscall [unknown] [k] 0x00007fff9f94a02c
2.20% 0x7fff9f94a02c null_syscall libc.so.6 [.] syscall
perf_get_misc_flags() function looks at the privilege bits to return
the corresponding flags to be used for the address symbol and these
privilege bit details are read from the sampled event register. In the
above snippet, address "0x00007fff9f94a02c" is shown as "k" (kernel) due
to the incorrect privilege bits captured in the sampled event register.
To address this case check whether the sampled address is in the kernel
area. Since this is specific to the latest platform, a new pmu flag
is added called "PPMU_P10" and is used to contain the proposed fix.
PPMU_P10_DD1 marked events are also included under PPMU_P10, hence
remove the code specific to PPMU_P10_DD1 marked events.
Signed-off-by: Anjali K <anjalik@linux.ibm.com>
Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com <mailto:atrajeev@linux.vnet.ibm.com>>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240528040356.2722275-1-anjalik@linux.ibm.com
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 reStructuredText 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.