2c733bb795
commit d3119bc985fb645ad3b2a9cf9952c1d56d9daaa3 upstream.
In order to fix perf's callchain parse error for LoongArch, we implement
perf_arch_fetch_caller_regs() which fills several necessary registers
used for callchain unwinding, including sp, fp, and era. This is similar
to the following commits.
commit b3eac0265bf6:
("arm: perf: Fix callchain parse error with kernel tracepoint events")
commit 5b09a094f2fb:
("arm64: perf: Fix callchain parse error with kernel tracepoint events")
commit 9a7e8ec0d4cc:
("riscv: perf: Fix callchain parse error with kernel tracepoint events")
Test with commands:
perf record -e sched:sched_switch -g --call-graph dwarf
perf report
Without this patch:
Children Self Command Shared Object Symbol
........ ........ ............. ................. ....................
43.41% 43.41% swapper [unknown] [k] 0000000000000000
10.94% 10.94% loong-container [unknown] [k] 0000000000000000
|
|--5.98%--0x12006ba38
|
|--2.56%--0x12006bb84
|
--2.40%--0x12006b6b8
With this patch, callchain can be parsed correctly:
Children Self Command Shared Object Symbol
........ ........ ............. ................. ....................
47.57% 47.57% swapper [kernel.vmlinux] [k] __schedule
|
---__schedule
26.76% 26.76% loong-container [kernel.vmlinux] [k] __schedule
|
|--13.78%--0x12006ba38
| |
| |--9.19%--__schedule
| |
| --4.59%--handle_syscall
| do_syscall
| sys_futex
| do_futex
| futex_wait
| futex_wait_queue_me
| hrtimer_start_range_ns
| __schedule
|
|--8.38%--0x12006bb84
| handle_syscall
| do_syscall
| sys_epoll_pwait
| do_epoll_wait
| schedule_hrtimeout_range_clock
| hrtimer_start_range_ns
| __schedule
|
--4.59%--0x12006b6b8
handle_syscall
do_syscall
sys_nanosleep
hrtimer_nanosleep
do_nanosleep
hrtimer_start_range_ns
__schedule
Cc: stable@vger.kernel.org
Fixes: b37042b2bb7cd751f0 ("LoongArch: Add perf events support")
Reported-by: Youling Tang <tangyouling@kylinos.cn>
Suggested-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.