1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <linux/module.h>
7#include <linux/ptrace.h>
8#include <linux/sched.h>
9#include <linux/ftrace.h>
10#include <asm/siginfo.h>
11#include <asm/signal.h>
12#include <asm/unistd.h>
13#include <frame_kern.h>
14#include <kern_util.h>
15#include <os.h>
16
17EXPORT_SYMBOL(block_signals);
18EXPORT_SYMBOL(unblock_signals);
19
20void block_signals_trace(void)
21{
22	block_signals();
23	if (current_thread_info())
24		trace_hardirqs_off();
25}
26
27void unblock_signals_trace(void)
28{
29	if (current_thread_info())
30		trace_hardirqs_on();
31	unblock_signals();
32}
33
34void um_trace_signals_on(void)
35{
36	if (current_thread_info())
37		trace_hardirqs_on();
38}
39
40void um_trace_signals_off(void)
41{
42	if (current_thread_info())
43		trace_hardirqs_off();
44}
45
46/*
47 * OK, we're invoking a handler
48 */
49static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
50{
51	sigset_t *oldset = sigmask_to_save();
52	int singlestep = 0;
53	unsigned long sp;
54	int err;
55
56	if (test_thread_flag(TIF_SINGLESTEP) && (current->ptrace & PT_PTRACED))
57		singlestep = 1;
58
59	/* Did we come from a system call? */
60	if (PT_REGS_SYSCALL_NR(regs) >= 0) {
61		/* If so, check system call restarting.. */
62		switch (PT_REGS_SYSCALL_RET(regs)) {
63		case -ERESTART_RESTARTBLOCK:
64		case -ERESTARTNOHAND:
65			PT_REGS_SYSCALL_RET(regs) = -EINTR;
66			break;
67
68		case -ERESTARTSYS:
69			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
70				PT_REGS_SYSCALL_RET(regs) = -EINTR;
71				break;
72			}
73			fallthrough;
74		case -ERESTARTNOINTR:
75			PT_REGS_RESTART_SYSCALL(regs);
76			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
77			break;
78		}
79	}
80
81	sp = PT_REGS_SP(regs);
82	if ((ksig->ka.sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
83		sp = current->sas_ss_sp + current->sas_ss_size;
84
85#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
86	if (!(ksig->ka.sa.sa_flags & SA_SIGINFO))
87		err = setup_signal_stack_sc(sp, ksig, regs, oldset);
88	else
89#endif
90		err = setup_signal_stack_si(sp, ksig, regs, oldset);
91
92	signal_setup_done(err, ksig, singlestep);
93}
94
95void do_signal(struct pt_regs *regs)
96{
97	struct ksignal ksig;
98	int handled_sig = 0;
99
100	while (get_signal(&ksig)) {
101		handled_sig = 1;
102		/* Whee!  Actually deliver the signal.  */
103		handle_signal(&ksig, regs);
104	}
105
106	/* Did we come from a system call? */
107	if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
108		/* Restart the system call - no handlers present */
109		switch (PT_REGS_SYSCALL_RET(regs)) {
110		case -ERESTARTNOHAND:
111		case -ERESTARTSYS:
112		case -ERESTARTNOINTR:
113			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
114			PT_REGS_RESTART_SYSCALL(regs);
115			break;
116		case -ERESTART_RESTARTBLOCK:
117			PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
118			PT_REGS_RESTART_SYSCALL(regs);
119			break;
120		}
121	}
122
123	/*
124	 * if there's no signal to deliver, we just put the saved sigmask
125	 * back
126	 */
127	if (!handled_sig)
128		restore_saved_sigmask();
129}
130