diff options
Diffstat (limited to 'arch/riscv/kernel/stacktrace.c')
| -rw-r--r-- | arch/riscv/kernel/stacktrace.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c new file mode 100644 index 000000000..9c34735c1 --- /dev/null +++ b/arch/riscv/kernel/stacktrace.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2008 ARM Limited + * Copyright (C) 2014 Regents of the University of California + */ + +#include <linux/export.h> +#include <linux/kallsyms.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/sched/task_stack.h> +#include <linux/stacktrace.h> +#include <linux/ftrace.h> + +register unsigned long sp_in_global __asm__("sp"); + +#ifdef CONFIG_FRAME_POINTER + +struct stackframe { + unsigned long fp; + unsigned long ra; +}; + +void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, + bool (*fn)(unsigned long, void *), void *arg) +{ + unsigned long fp, sp, pc; + + if (regs) { + fp = frame_pointer(regs); + sp = user_stack_pointer(regs); + pc = instruction_pointer(regs); + } else if (task == NULL || task == current) { + const register unsigned long current_sp = sp_in_global; + fp = (unsigned long)__builtin_frame_address(0); + sp = current_sp; + pc = (unsigned long)walk_stackframe; + } else { + /* task blocked in __switch_to */ + fp = task->thread.s[0]; + sp = task->thread.sp; + pc = task->thread.ra; + } + + for (;;) { + unsigned long low, high; + struct stackframe *frame; + + if (unlikely(!__kernel_text_address(pc) || fn(pc, arg))) + break; + + /* Validate frame pointer */ + low = sp + sizeof(struct stackframe); + high = ALIGN(sp, THREAD_SIZE); + if (unlikely(fp < low || fp > high || fp & 0x7)) + break; + /* Unwind stack frame */ + frame = (struct stackframe *)fp - 1; + sp = fp; + if (regs && (regs->epc == pc) && (frame->fp & 0x7)) { + fp = frame->ra; + pc = regs->ra; + } else { + fp = frame->fp; + pc = ftrace_graph_ret_addr(current, NULL, frame->ra, + &frame->ra); + } + + } +} + +#else /* !CONFIG_FRAME_POINTER */ + +void notrace walk_stackframe(struct task_struct *task, + struct pt_regs *regs, bool (*fn)(unsigned long, void *), void *arg) +{ + unsigned long sp, pc; + unsigned long *ksp; + + if (regs) { + sp = user_stack_pointer(regs); + pc = instruction_pointer(regs); + } else if (task == NULL || task == current) { + sp = sp_in_global; + pc = (unsigned long)walk_stackframe; + } else { + /* task blocked in __switch_to */ + sp = task->thread.sp; + pc = task->thread.ra; + } + + if (unlikely(sp & 0x7)) + return; + + ksp = (unsigned long *)sp; + while (!kstack_end(ksp)) { + if (__kernel_text_address(pc) && unlikely(fn(pc, arg))) + break; + pc = READ_ONCE_NOCHECK(*ksp++) - 0x4; + } +} + +#endif /* CONFIG_FRAME_POINTER */ + + +static bool print_trace_address(unsigned long pc, void *arg) +{ + const char *loglvl = arg; + + print_ip_sym(loglvl, pc); + return false; +} + +void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) +{ + pr_cont("Call Trace:\n"); + walk_stackframe(task, NULL, print_trace_address, (void *)loglvl); +} + +static bool save_wchan(unsigned long pc, void *arg) +{ + if (!in_sched_functions(pc)) { + unsigned long *p = arg; + *p = pc; + return true; + } + return false; +} + +unsigned long get_wchan(struct task_struct *task) +{ + unsigned long pc = 0; + + if (likely(task && task != current && task->state != TASK_RUNNING)) + walk_stackframe(task, NULL, save_wchan, &pc); + return pc; +} + + +#ifdef CONFIG_STACKTRACE + +static bool __save_trace(unsigned long pc, void *arg, bool nosched) +{ + struct stack_trace *trace = arg; + + if (unlikely(nosched && in_sched_functions(pc))) + return false; + if (unlikely(trace->skip > 0)) { + trace->skip--; + return false; + } + + trace->entries[trace->nr_entries++] = pc; + return (trace->nr_entries >= trace->max_entries); +} + +static bool save_trace(unsigned long pc, void *arg) +{ + return __save_trace(pc, arg, false); +} + +/* + * Save stack-backtrace addresses into a stack_trace buffer. + */ +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + walk_stackframe(tsk, NULL, save_trace, trace); +} +EXPORT_SYMBOL_GPL(save_stack_trace_tsk); + +void save_stack_trace(struct stack_trace *trace) +{ + save_stack_trace_tsk(NULL, trace); +} +EXPORT_SYMBOL_GPL(save_stack_trace); + +#endif /* CONFIG_STACKTRACE */ |