[PATCH v10 03/11] arm64: Make get_wchan() use arch_stack_walk()
From: <hidden>
Date: 2021-10-15 02:59:23
Also in:
live-patching, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
From: "Madhavan T. Venkataraman" <redacted> Currently, get_wchan() in ARM64 code walks the stack using start_backtrace() and unwind_frame(). Make it use arch_stack_walk() instead. This makes maintenance easier. Signed-off-by: Madhavan T. Venkataraman <redacted> --- arch/arm64/kernel/process.c | 38 ++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index c8989b999250..48ed89acce0d 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c@@ -544,11 +544,27 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, return last; } +struct wchan_info { + unsigned long pc; + int count; +}; + +static bool get_wchan_cb(void *arg, unsigned long pc) +{ + struct wchan_info *wchan_info = arg; + + if (!in_sched_functions(pc)) { + wchan_info->pc = pc; + return false; + } + return wchan_info->count++ < 16; +} + unsigned long get_wchan(struct task_struct *p) { - struct stackframe frame; - unsigned long stack_page, ret = 0; - int count = 0; + unsigned long stack_page; + struct wchan_info wchan_info; + if (!p || p == current || task_is_running(p)) return 0;
@@ -556,20 +572,12 @@ unsigned long get_wchan(struct task_struct *p) if (!stack_page) return 0; - start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p)); + wchan_info.pc = 0; + wchan_info.count = 0; + arch_stack_walk(get_wchan_cb, &wchan_info, p, NULL); - do { - if (unwind_frame(p, &frame)) - goto out; - if (!in_sched_functions(frame.pc)) { - ret = frame.pc; - goto out; - } - } while (count++ < 16); - -out: put_task_stack(p); - return ret; + return wchan_info.pc; } unsigned long arch_align_stack(unsigned long sp)
--
2.25.1
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