void notrace op_mips_backtrace(struct pt_regs *const regs, unsigned int depth)
{
	struct stackframe frame = { .sp = regs->regs[29],
				    .pc = regs->cp0_epc,
				    .ra = regs->regs[31] };
	const int userspace = user_mode(regs);
	const unsigned long low_addr = ALIGN(frame.sp, THREAD_SIZE);

	if (userspace)
		do_user_backtrace(low_addr, &frame, depth);
	else
		do_kernel_backtrace(low_addr, &frame, depth);
}
Exemple #2
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static kern_return_t do_kernel_backtrace(
	thread_t thread,
	struct x86_kernel_state *regs, 
	uint64_t *frames,
	mach_msg_type_number_t *start_idx,
	mach_msg_type_number_t max_idx)
{
	uint64_t kernStackMin = (uint64_t)thread->kernel_stack;
    uint64_t kernStackMax = (uint64_t)kernStackMin + kernel_stack_size;
	mach_msg_type_number_t ct = *start_idx;
	kern_return_t kr = KERN_FAILURE;

#if __LP64__
	uint64_t currPC = 0ULL;
	uint64_t currFP = 0ULL;
	uint64_t prevPC = 0ULL;
	uint64_t prevFP = 0ULL;
	if(KERN_SUCCESS != chudxnu_kern_read(&currPC, (vm_offset_t)&(regs->k_rip), sizeof(uint64_t))) {
		return KERN_FAILURE;
	}
	if(KERN_SUCCESS != chudxnu_kern_read(&currFP, (vm_offset_t)&(regs->k_rbp), sizeof(uint64_t))) {
		return KERN_FAILURE;
	}
#else
	uint32_t currPC = 0U;
	uint32_t currFP = 0U;
	uint32_t prevPC = 0U;
	uint32_t prevFP = 0U;
	if(KERN_SUCCESS != chudxnu_kern_read(&currPC, (vm_offset_t)&(regs->k_eip), sizeof(uint32_t))) {
		return KERN_FAILURE;
	}
	if(KERN_SUCCESS != chudxnu_kern_read(&currFP, (vm_offset_t)&(regs->k_ebp), sizeof(uint32_t))) {
		return KERN_FAILURE;
	}
#endif

	if(*start_idx >= max_idx)
		return KERN_RESOURCE_SHORTAGE;	// no frames traced
	
	if(!currPC) {
		return KERN_FAILURE;
	}

	frames[ct++] = (uint64_t)currPC;

	// build a backtrace of this kernel state
#if __LP64__
	while(VALID_STACK_ADDRESS64(TRUE, currFP, kernStackMin, kernStackMax)) {
		// this is the address where caller lives in the user thread
		uint64_t caller = currFP + sizeof(uint64_t);
#else
	while(VALID_STACK_ADDRESS(TRUE, currFP, kernStackMin, kernStackMax)) {
		uint32_t caller = (uint32_t)currFP + sizeof(uint32_t);
#endif

        if(!currFP || !currPC) {
            currPC = 0;
            break;
        }

        if(ct >= max_idx) {
			*start_idx = ct;
            return KERN_RESOURCE_SHORTAGE;
        }

		/* read our caller */
		kr = chudxnu_kern_read(&currPC, (vm_offset_t)caller, sizeof(currPC));

		if(kr != KERN_SUCCESS || !currPC) {
			currPC = 0UL;
			break;
		}

        /* 
         * retrive contents of the frame pointer and advance to the next stack
         * frame if it's valid 
         */
        prevFP = 0;
		kr = chudxnu_kern_read(&prevFP, (vm_offset_t)currFP, sizeof(currPC));

#if __LP64__
        if(VALID_STACK_ADDRESS64(TRUE, prevFP, kernStackMin, kernStackMax)) {
#else
        if(VALID_STACK_ADDRESS(TRUE, prevFP, kernStackMin, kernStackMax)) {
#endif
            frames[ct++] = (uint64_t)currPC;
            prevPC = currPC;
        }
        if(prevFP <= currFP) {
            break;
        } else {
            currFP = prevFP;
        }	
	}

	*start_idx = ct;
	return KERN_SUCCESS;
}



__private_extern__
kern_return_t chudxnu_thread_get_callstack64(
	thread_t		thread,
	uint64_t		*callstack,
	mach_msg_type_number_t	*count,
	boolean_t		user_only)
{
	kern_return_t kr = KERN_FAILURE;
    task_t task = thread->task;
    uint64_t currPC = 0ULL;
	boolean_t supervisor = FALSE;
    mach_msg_type_number_t bufferIndex = 0;
    mach_msg_type_number_t bufferMaxIndex = *count;
	x86_saved_state_t *tagged_regs = NULL;		// kernel register state
	x86_saved_state64_t *regs64 = NULL;
	x86_saved_state32_t *regs32 = NULL;
	x86_saved_state32_t *u_regs32 = NULL;
	x86_saved_state64_t *u_regs64 = NULL;
	struct x86_kernel_state *kregs = NULL;

	if(ml_at_interrupt_context()) {
		
		if(user_only) {
			/* can't backtrace user state on interrupt stack. */
			return KERN_FAILURE;
		}

		/* backtracing at interrupt context? */
		 if(thread == current_thread() && current_cpu_datap()->cpu_int_state) {
			/* 
			 * Locate the registers for the interrupted thread, assuming it is
			 * current_thread(). 
			 */
			tagged_regs = current_cpu_datap()->cpu_int_state;
			
			if(is_saved_state64(tagged_regs)) {
				/* 64 bit registers */
				regs64 = saved_state64(tagged_regs);
				supervisor = ((regs64->isf.cs & SEL_PL) != SEL_PL_U);
			} else {
				/* 32 bit registers */
				regs32 = saved_state32(tagged_regs);
				supervisor = ((regs32->cs & SEL_PL) != SEL_PL_U);
			}
		} 
	}

	if(!ml_at_interrupt_context() && kernel_task == task) {

		if(!thread->kernel_stack) {
			return KERN_FAILURE;
		}

		// Kernel thread not at interrupt context
		kregs = (struct x86_kernel_state *)NULL;

		// nofault read of the thread->kernel_stack pointer
		if(KERN_SUCCESS != chudxnu_kern_read(&kregs, (vm_offset_t)&(thread->kernel_stack), sizeof(void *))) {
			return KERN_FAILURE;
		}

		// Adjust to find the saved kernel state
		kregs = STACK_IKS((vm_offset_t)(uintptr_t)kregs);

		supervisor = TRUE;
	} else if(!tagged_regs) {
		/* 
		 * not at interrupt context, or tracing a different thread than
		 * current_thread() at interrupt context 
		 */
		tagged_regs = USER_STATE(thread);
		if(is_saved_state64(tagged_regs)) {
			/* 64 bit registers */
			regs64 = saved_state64(tagged_regs);
			supervisor = ((regs64->isf.cs & SEL_PL) != SEL_PL_U); 
		} else {
			/* 32 bit registers */
			regs32 = saved_state32(tagged_regs);
			supervisor = ((regs32->cs & SEL_PL) != SEL_PL_U);
		}
	}

	*count = 0; 

	if(supervisor) {
		// the caller only wants a user callstack.
		if(user_only) {
			// bail - we've only got kernel state
			return KERN_FAILURE;
		}
	} else {
		// regs32(64) is not in supervisor mode.
		u_regs32 = regs32;
		u_regs64 = regs64;
		regs32 = NULL;
		regs64 = NULL;
	}

	if (user_only) {
		/* we only want to backtrace the user mode */
		if(!(u_regs32 || u_regs64)) {
			/* no user state to look at */
			return KERN_FAILURE;
		}
	}

	/* 
	 * Order of preference for top of stack:
	 * 64 bit kernel state (not likely)
	 * 32 bit kernel state
	 * 64 bit user land state
	 * 32 bit user land state
	 */

	if(kregs) {
		/*
		 * nofault read of the registers from the kernel stack (as they can
		 * disappear on the fly).
		 */

#if __LP64__
		if(KERN_SUCCESS != chudxnu_kern_read(&currPC, (vm_offset_t)&(kregs->k_rip), sizeof(uint64_t))) {
			return KERN_FAILURE;
		}
#else
		uint32_t tmp;
		if(KERN_SUCCESS != chudxnu_kern_read(&tmp, (vm_offset_t)&(kregs->k_eip), sizeof(uint32_t))) {
			return KERN_FAILURE;
		}
		currPC = (uint64_t)tmp;
#endif
	} else if(regs64) {
		currPC = regs64->isf.rip;
	} else if(regs32) {
		currPC = (uint64_t) regs32->eip;
	} else if(u_regs64) {
		currPC = u_regs64->isf.rip;
	} else if(u_regs32) {
		currPC = (uint64_t) u_regs32->eip;
	}
	
	if(!currPC) {
		/* no top of the stack, bail out */
		return KERN_FAILURE;
	}

	bufferIndex = 0;
		
	if(bufferMaxIndex < 1) {
		*count = 0;
		return KERN_RESOURCE_SHORTAGE;
	}

	/* backtrace kernel */
	if(kregs) {
		addr64_t address = 0ULL;
		size_t size = 0UL;

		// do the backtrace
		kr = do_kernel_backtrace(thread, kregs, callstack, &bufferIndex, bufferMaxIndex);

		// and do a nofault read of (r|e)sp
#if __LP64__
		uint64_t rsp = 0ULL;
		size = sizeof(uint64_t);
		
		if(KERN_SUCCESS != chudxnu_kern_read(&address, (vm_offset_t)&(kregs->k_rsp), size)) {
			address = 0ULL;
		}
#else
		uint32_t rsp = 0ULL, tmp = 0ULL;
		size = sizeof(uint32_t);

		if(KERN_SUCCESS != chudxnu_kern_read(&tmp, (vm_offset_t)&(kregs->k_esp), size)) {
			address = 0ULL;
		} else {
			address = (addr64_t)tmp;
		}
#endif

		if(address && KERN_SUCCESS == chudxnu_kern_read(&rsp, (vm_offset_t)address, size) && bufferIndex < bufferMaxIndex) {
			callstack[bufferIndex++] = (uint64_t)rsp;
		}
	} else if(regs64) {
		uint64_t rsp = 0ULL;

		// backtrace the 64bit side.
		kr = do_backtrace64(task, thread, regs64, callstack, &bufferIndex, 
			bufferMaxIndex, TRUE);

		if(KERN_SUCCESS == chudxnu_kern_read(&rsp, (vm_offset_t) regs64->isf.rsp, sizeof(uint64_t)) && 
			bufferIndex < bufferMaxIndex) {
			callstack[bufferIndex++] = rsp;
		}

	} else if(regs32) {
		uint32_t esp = 0UL;

		// backtrace the 32bit side.
		kr = do_backtrace32(task, thread, regs32, callstack, &bufferIndex, 
			bufferMaxIndex, TRUE);
		
		if(KERN_SUCCESS == chudxnu_kern_read(&esp, (vm_offset_t) regs32->uesp, sizeof(uint32_t)) && 
			bufferIndex < bufferMaxIndex) {
			callstack[bufferIndex++] = (uint64_t) esp;
		}
	} else if(u_regs64) {
		/* backtrace user land */
		uint64_t rsp = 0ULL;
		
		kr = do_backtrace64(task, thread, u_regs64, callstack, &bufferIndex, 
			bufferMaxIndex, FALSE);

		if(KERN_SUCCESS == chudxnu_task_read(task, &rsp, (addr64_t) u_regs64->isf.rsp, sizeof(uint64_t)) && 
			bufferIndex < bufferMaxIndex) {
			callstack[bufferIndex++] = rsp;
		}

	} else if(u_regs32) {
		uint32_t esp = 0UL;
		
		kr = do_backtrace32(task, thread, u_regs32, callstack, &bufferIndex, 
			bufferMaxIndex, FALSE);

		if(KERN_SUCCESS == chudxnu_task_read(task, &esp, (addr64_t) u_regs32->uesp, sizeof(uint32_t)) && 
			bufferIndex < bufferMaxIndex) {
			callstack[bufferIndex++] = (uint64_t) esp;
		}
	}

    *count = bufferIndex;
    return kr;
}