Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4) #include <linux/sched/debug.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) #include <linux/stacktrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <asm/sections.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <asm/stacktrace.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <asm/traps.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * Unwind the current stack frame and store the new register values in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  * structure passed as argument. Unwinding is equivalent to a function return,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  * hence the new PC value rather than LR should be used for backtrace.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17)  * With framepointer enabled, a simple function prologue looks like this:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18)  *	mov	ip, sp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19)  *	stmdb	sp!, {fp, ip, lr, pc}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20)  *	sub	fp, ip, #4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22)  * A simple function epilogue looks like this:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23)  *	ldm	sp, {fp, sp, pc}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25)  * When compiled with clang, pc and sp are not pushed. A simple function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26)  * prologue looks like this when built with clang:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28)  *	stmdb	{..., fp, lr}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29)  *	add	fp, sp, #x
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30)  *	sub	sp, sp, #y
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  * A simple function epilogue looks like this when built with clang:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34)  *	sub	sp, fp, #x
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  *	ldm	{..., fp, pc}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38)  * Note that with framepointer enabled, even the leaf functions have the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39)  * prologue and epilogue, therefore we can ignore the LR value in this case.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) int notrace unwind_frame(struct stackframe *frame)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	unsigned long high, low;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	unsigned long fp = frame->fp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	/* only go to a higher address on the stack */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	low = frame->sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	high = ALIGN(low, THREAD_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) #ifdef CONFIG_CC_IS_CLANG
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	/* check current frame pointer is within bounds */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	if (fp < low + 4 || fp > high - 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	frame->sp = frame->fp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	frame->fp = *(unsigned long *)(fp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	frame->pc = *(unsigned long *)(fp + 4);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	/* check current frame pointer is within bounds */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	if (fp < low + 12 || fp > high - 4)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 		return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	/* restore the registers from the stack frame */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	frame->fp = *(unsigned long *)(fp - 12);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 	frame->sp = *(unsigned long *)(fp - 8);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	frame->pc = *(unsigned long *)(fp - 4);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) void notrace walk_stackframe(struct stackframe *frame,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		     int (*fn)(struct stackframe *, void *), void *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 		int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		if (fn(frame, data))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 		ret = unwind_frame(frame);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 		if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) EXPORT_SYMBOL(walk_stackframe);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) #ifdef CONFIG_STACKTRACE
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) struct stack_trace_data {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	struct stack_trace *trace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	unsigned int no_sched_functions;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	unsigned int skip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) static int save_trace(struct stackframe *frame, void *d)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	struct stack_trace_data *data = d;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	struct stack_trace *trace = data->trace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	struct pt_regs *regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	unsigned long addr = frame->pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	if (data->no_sched_functions && in_sched_functions(addr))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	if (data->skip) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 		data->skip--;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	trace->entries[trace->nr_entries++] = addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	if (trace->nr_entries >= trace->max_entries)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	if (!in_entry_text(frame->pc))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	regs = (struct pt_regs *)frame->sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	if ((unsigned long)&regs[1] > ALIGN(frame->sp, THREAD_SIZE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	trace->entries[trace->nr_entries++] = regs->ARM_pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	return trace->nr_entries >= trace->max_entries;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) /* This must be noinline to so that our skip calculation works correctly */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) static noinline void __save_stack_trace(struct task_struct *tsk,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	struct stack_trace *trace, unsigned int nosched)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 	struct stack_trace_data data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 	struct stackframe frame;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 	data.trace = trace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	data.skip = trace->skip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	data.no_sched_functions = nosched;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 	if (tsk != current) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) #ifdef CONFIG_SMP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 		 * What guarantees do we have here that 'tsk' is not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		 * running on another CPU?  For now, ignore it as we
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 		 * can't guarantee we won't explode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) #else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		frame.fp = thread_saved_fp(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		frame.sp = thread_saved_sp(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 		frame.lr = 0;		/* recovered from the stack */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 		frame.pc = thread_saved_pc(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		/* We don't want this function nor the caller */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		data.skip += 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 		frame.fp = (unsigned long)__builtin_frame_address(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		frame.sp = current_stack_pointer;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		frame.lr = (unsigned long)__builtin_return_address(0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		frame.pc = (unsigned long)__save_stack_trace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	walk_stackframe(&frame, save_trace, &data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	struct stack_trace_data data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	struct stackframe frame;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	data.trace = trace;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	data.skip = trace->skip;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	data.no_sched_functions = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	frame.fp = regs->ARM_fp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	frame.sp = regs->ARM_sp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	frame.lr = regs->ARM_lr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	frame.pc = regs->ARM_pc;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 	walk_stackframe(&frame, save_trace, &data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	__save_stack_trace(tsk, trace, 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) EXPORT_SYMBOL(save_stack_trace_tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) void save_stack_trace(struct stack_trace *trace)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	__save_stack_trace(current, trace, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) EXPORT_SYMBOL_GPL(save_stack_trace);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) #endif