From: chenmiao <chenmiao...@gmail.com> Hello erverone,
This patch contains basic ftrace support for OR1K platform. Specifically, function tracer (HAVE_FUNCTION_TRACER), function graph tracer (HAVE_FUNCTION_GRAPH_TRACER), and a frame pointer test (HAVE_FUNCTION_GRAPH_FP_TEST) are implemented following the instructions in Documentation/trace/ftrace-design.txt. Below, I briefly explain why FTRACE_GRAPH was not enabled. During testing, it was found that when fgraph is used with static ftrace, it calls the ftrace_startup_subops function. This function is used by register_ftrace_graph and always returns the EINVAL value in the case of static ftrace. So, we disable the fgraph. *If re-initialization is attempted, it may lead to severe consequences*, leading to the following issues: [ 76.040000] ------------[ cut here ]------------ [ 76.040000] WARNING: CPU: 0 PID: 140 at kernel/trace/fgraph.c:1328 register_ftrace_graph+0x750/0x7e4 [ 76.040000] function graph ops registered again [ 76.040000] Modules linked in: [ 76.040000] CPU: 0 UID: 0 PID: 140 Comm: bash Not tainted 6.17.0-rc3-00014-gda230ee3ff1c #1 NONE [ 76.040000] Call trace: [ 76.040000] [<0b43fbe5>] dump_stack_lvl+0x8c/0xc4 [ 76.040000] [<d2655aeb>] ? register_ftrace_graph+0x750/0x7e4 [ 76.040000] [<22405ca2>] dump_stack+0x1c/0x2c [ 76.040000] [<04b97f00>] __warn+0xcc/0x1ac [ 76.040000] [<d2655aeb>] ? register_ftrace_graph+0x750/0x7e4 [ 76.040000] [<34636c77>] warn_slowpath_fmt+0x1e8/0x1f0 [ 76.040000] [<d2655aeb>] register_ftrace_graph+0x750/0x7e4 [ 76.040000] [<94bcf66b>] ? do_ftrace_graph_caller+0x2c/0x40 [ 76.040000] [<863d51d0>] ? _raw_spin_unlock_irqrestore+0x3c/0x50 [ 76.040000] [<5e3d7fcf>] graph_trace_init+0x60/0xa0 [ 76.040000] [<239e8587>] tracing_set_tracer+0x180/0x29c [ 76.040000] [<0bedd84e>] ? mutex_unlock+0x24/0x80 [ 76.040000] [<21c17ace>] tracing_set_trace_write+0xa4/0x118 [ 76.040000] [<0d244535>] vfs_write+0x108/0x5ac [ 76.040000] [<94bcf66b>] ? do_ftrace_graph_caller+0x2c/0x40 [ 76.040000] [<c15d06f8>] ? fdget_pos+0x20/0x210 [ 76.040000] [<bc6b8897>] ksys_write+0x94/0x150 [ 76.040000] [<06a3d204>] sys_write+0x38/0x4c [ 76.040000] [<2cd910fd>] ? _syscall_return+0x0/0x4 [ 76.040000] ---[ end trace 0000000000000000 ]--- Thanks, Chen Miao chenmiao (1): openrisc: Add the basic static ftrace support arch/openrisc/Kconfig | 1 + arch/openrisc/configs/or1ksim_defconfig | 2 +- arch/openrisc/configs/virt_defconfig | 1 + arch/openrisc/include/asm/ftrace.h | 29 ++++ arch/openrisc/kernel/Makefile | 7 + arch/openrisc/kernel/entry-ftrace.S | 185 ++++++++++++++++++++++++ arch/openrisc/kernel/ftrace.c | 35 +++++ 7 files changed, 259 insertions(+), 1 deletion(-) create mode 100644 arch/openrisc/include/asm/ftrace.h create mode 100644 arch/openrisc/kernel/entry-ftrace.S create mode 100644 arch/openrisc/kernel/ftrace.c -- 2.45.2
