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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. commitb3eac0265b: ("arm: perf: Fix callchain parse error with kernel tracepoint events") commit5b09a094f2: ("arm64: perf: Fix callchain parse error with kernel tracepoint events") commit9a7e8ec0d4: ("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:b37042b2bb("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.