diff options
Diffstat (limited to 'arch/arm64/kernel/stacktrace.c')
| -rw-r--r-- | arch/arm64/kernel/stacktrace.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c new file mode 100644 index 000000000..bb482ec04 --- /dev/null +++ b/arch/arm64/kernel/stacktrace.c @@ -0,0 +1,196 @@ +/* + * Stack tracing support + * + * Copyright (C) 2012 ARM Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/ftrace.h> +#include <linux/kprobes.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/sched/task_stack.h> +#include <linux/stacktrace.h> + +#include <asm/irq.h> +#include <asm/stack_pointer.h> +#include <asm/stacktrace.h> + +/* + * AArch64 PCS assigns the frame pointer to x29. + * + * A simple function prologue looks like this: + * sub sp, sp, #0x10 + * stp x29, x30, [sp] + * mov x29, sp + * + * A simple function epilogue looks like this: + * mov sp, x29 + * ldp x29, x30, [sp] + * add sp, sp, #0x10 + */ +int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame) +{ + unsigned long fp = frame->fp; + + if (fp & 0xf) + return -EINVAL; + + if (!tsk) + tsk = current; + + if (!on_accessible_stack(tsk, fp, NULL)) + return -EINVAL; + + frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); + frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8)); + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + if (tsk->ret_stack && + (frame->pc == (unsigned long)return_to_handler)) { + if (WARN_ON_ONCE(frame->graph == -1)) + return -EINVAL; + if (frame->graph < -1) + frame->graph += FTRACE_NOTRACE_DEPTH; + + /* + * This is a case where function graph tracer has + * modified a return address (LR) in a stack frame + * to hook a function return. + * So replace it to an original value. + */ + frame->pc = tsk->ret_stack[frame->graph--].ret; + } +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + + /* + * Frames created upon entry from EL0 have NULL FP and PC values, so + * don't bother reporting these. Frames created by __noreturn functions + * might have a valid FP even if PC is bogus, so only terminate where + * both are NULL. + */ + if (!frame->fp && !frame->pc) + return -EINVAL; + + return 0; +} +NOKPROBE_SYMBOL(unwind_frame); + +void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame, + int (*fn)(struct stackframe *, void *), void *data) +{ + while (1) { + int ret; + + if (fn(frame, data)) + break; + ret = unwind_frame(tsk, frame); + if (ret < 0) + break; + } +} +NOKPROBE_SYMBOL(walk_stackframe); + +#ifdef CONFIG_STACKTRACE +struct stack_trace_data { + struct stack_trace *trace; + unsigned int no_sched_functions; + unsigned int skip; +}; + +static int save_trace(struct stackframe *frame, void *d) +{ + struct stack_trace_data *data = d; + struct stack_trace *trace = data->trace; + unsigned long addr = frame->pc; + + if (data->no_sched_functions && in_sched_functions(addr)) + return 0; + if (data->skip) { + data->skip--; + return 0; + } + + trace->entries[trace->nr_entries++] = addr; + + return trace->nr_entries >= trace->max_entries; +} + +void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) +{ + struct stack_trace_data data; + struct stackframe frame; + + data.trace = trace; + data.skip = trace->skip; + data.no_sched_functions = 0; + + frame.fp = regs->regs[29]; + frame.pc = regs->pc; +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + frame.graph = current->curr_ret_stack; +#endif + + walk_stackframe(current, &frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; +} + +static noinline void __save_stack_trace(struct task_struct *tsk, + struct stack_trace *trace, unsigned int nosched) +{ + struct stack_trace_data data; + struct stackframe frame; + + if (!try_get_task_stack(tsk)) + return; + + data.trace = trace; + data.skip = trace->skip; + data.no_sched_functions = nosched; + + if (tsk != current) { + frame.fp = thread_saved_fp(tsk); + frame.pc = thread_saved_pc(tsk); + } else { + /* We don't want this function nor the caller */ + data.skip += 2; + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.pc = (unsigned long)__save_stack_trace; + } +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + frame.graph = tsk->curr_ret_stack; +#endif + + walk_stackframe(tsk, &frame, save_trace, &data); + if (trace->nr_entries < trace->max_entries) + trace->entries[trace->nr_entries++] = ULONG_MAX; + + put_task_stack(tsk); +} +EXPORT_SYMBOL_GPL(save_stack_trace_tsk); + +void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) +{ + __save_stack_trace(tsk, trace, 1); +} + +void save_stack_trace(struct stack_trace *trace) +{ + __save_stack_trace(current, trace, 0); +} + +EXPORT_SYMBOL_GPL(save_stack_trace); +#endif |