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