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1a74833182
Currently, userstacktrace is unsupported for riscv. So use the
perf_callchain_user() code as blueprint to implement the
arch_stack_walk_user() which add userstacktrace support on riscv.
Meanwhile, we can use arch_stack_walk_user() to simplify the implementation
of perf_callchain_user().
A ftrace test case is shown as below:
# cd /sys/kernel/debug/tracing
# echo 1 > options/userstacktrace
# echo 1 > options/sym-userobj
# echo 1 > events/sched/sched_process_fork/enable
# cat trace
......
bash-178 [000] ...1. 97.968395: sched_process_fork: comm=bash pid=178 child_comm=bash child_pid=231
bash-178 [000] ...1. 97.970075: <user stack trace>
=> /lib/libc.so.6[+0xb5090]
Also a simple perf test is ok as below:
# perf record -e cpu-clock --call-graph fp top
# perf report --call-graph
.....
[[31m 66.54%[[m 0.00% top [kernel.kallsyms] [k] ret_from_exception
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---ret_from_exception
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|--[[31m58.97%[[m--do_trap_ecall_u
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| |--[[31m17.34%[[m--__riscv_sys_read
| | ksys_read
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| | --[[31m16.88%[[m--vfs_read
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| | |--[[31m10.90%[[m--seq_read
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Tested-by: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20240708032847.2998158-3-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
39 lines
1.1 KiB
C
39 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2019 Hangzhou C-SKY Microsystems co.,ltd. */
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#include <linux/perf_event.h>
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#include <linux/uaccess.h>
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#include <asm/stacktrace.h>
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static bool fill_callchain(void *entry, unsigned long pc)
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{
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return perf_callchain_store(entry, pc) == 0;
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}
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/*
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* This will be called when the target is in user mode
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* This function will only be called when we use
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* "PERF_SAMPLE_CALLCHAIN" in
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* kernel/events/core.c:perf_prepare_sample()
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*
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* How to trigger perf_callchain_[user/kernel] :
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* $ perf record -e cpu-clock --call-graph fp ./program
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* $ perf report --call-graph
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*
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* On RISC-V platform, the program being sampled and the C library
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* need to be compiled with -fno-omit-frame-pointer, otherwise
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* the user stack will not contain function frame.
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*/
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void perf_callchain_user(struct perf_callchain_entry_ctx *entry,
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struct pt_regs *regs)
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{
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arch_stack_walk_user(fill_callchain, entry, regs);
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}
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void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
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struct pt_regs *regs)
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{
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walk_stackframe(NULL, regs, fill_callchain, entry);
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}
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