Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/ptrace.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/task_stack.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) #include <asm/syscall.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) static int collect_syscall(struct task_struct *target, struct syscall_info *info)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 	unsigned long args[6] = { };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 	struct pt_regs *regs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 	if (!try_get_task_stack(target)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 		/* Task has no stack, so the task isn't in a syscall. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 		memset(info, 0, sizeof(*info));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 		info->data.nr = -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 	regs = task_pt_regs(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 	if (unlikely(!regs)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 		put_task_stack(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 		return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	info->sp = user_stack_pointer(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	info->data.instruction_pointer = instruction_pointer(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	info->data.nr = syscall_get_nr(target, regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	if (info->data.nr != -1L)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 		syscall_get_arguments(target, regs, args);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 	info->data.args[0] = args[0];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	info->data.args[1] = args[1];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 	info->data.args[2] = args[2];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	info->data.args[3] = args[3];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	info->data.args[4] = args[4];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 	info->data.args[5] = args[5];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 	put_task_stack(target);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)  * task_current_syscall - Discover what a blocked task is doing.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)  * @target:		thread to examine
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)  * @info:		structure with the following fields:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)  *			 .sp        - filled with user stack pointer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)  *			 .data.nr   - filled with system call number or -1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50)  *			 .data.args - filled with @maxargs system call arguments
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)  *			 .data.instruction_pointer - filled with user PC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)  * If @target is blocked in a system call, returns zero with @info.data.nr
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54)  * set to the call's number and @info.data.args filled in with its
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)  * arguments. Registers not used for system call arguments may not be available
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)  * and it is not kosher to use &struct user_regset calls while the system
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)  * call is still in progress.  Note we may get this result if @target
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58)  * has finished its system call but not yet returned to user mode, such
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)  * as when it's stopped for signal handling or syscall exit tracing.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)  * If @target is blocked in the kernel during a fault or exception,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)  * returns zero with *@info.data.nr set to -1 and does not fill in
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63)  * @info.data.args. If so, it's now safe to examine @target using
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)  * &struct user_regset get() calls as long as we're sure @target won't return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)  * to user mode.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67)  * Returns -%EAGAIN if @target does not remain blocked.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) int task_current_syscall(struct task_struct *target, struct syscall_info *info)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) 	long state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 	unsigned long ncsw;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) 	if (target == current)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) 		return collect_syscall(target, info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) 	state = target->state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) 	if (unlikely(!state))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) 		return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) 	ncsw = wait_task_inactive(target, state);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) 	if (unlikely(!ncsw) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) 	    unlikely(collect_syscall(target, info)) ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) 	    unlikely(wait_task_inactive(target, state) != ncsw))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) 		return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) }