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	 * This closes a way to execute a system call on the host.  If
125	 * you set a breakpoint on a system call instruction and singlestep
126	 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
127	 * rather than PTRACE_SYSCALL it, allowing the system call to execute
128	 * on the host.  The tracing thread will check this flag and
129	 * PTRACE_SYSCALL if necessary.
130	 */
131	if (test_thread_flag(TIF_SINGLESTEP))
132		current->thread.singlestep_syscall =
133			is_syscall(PT_REGS_IP(&current->thread.regs));
134
135	/*
136	 * if there's no signal to deliver, we just put the saved sigmask
137	 * back
138	 */
139	if (!handled_sig)
140		restore_saved_sigmask();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
141}

 
  1/*
  2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include <linux/module.h>
  7#include <linux/ptrace.h>
  8#include <linux/sched.h>
 
  9#include <asm/siginfo.h>
 10#include <asm/signal.h>
 11#include <asm/unistd.h>
 12#include "frame_kern.h"
 13#include "kern_util.h"
 14#include <sysdep/sigcontext.h>
 15
 16EXPORT_SYMBOL(block_signals);
 17EXPORT_SYMBOL(unblock_signals);
 18
 19#define _S(nr) (1<<((nr)-1))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 20
 21#define _BLOCKABLE (~(_S(SIGKILL) | _S(SIGSTOP)))
 
 
 
 
 22
 23/*
 24 * OK, we're invoking a handler
 25 */
 26static int handle_signal(struct pt_regs *regs, unsigned long signr,
 27			 struct k_sigaction *ka, siginfo_t *info,
 28			 sigset_t *oldset)
 29{
 
 
 30	unsigned long sp;
 31	int err;
 32
 33	/* Always make any pending restarted system calls return -EINTR */
 34	current_thread_info()->restart_block.fn = do_no_restart_syscall;
 35
 36	/* Did we come from a system call? */
 37	if (PT_REGS_SYSCALL_NR(regs) >= 0) {
 38		/* If so, check system call restarting.. */
 39		switch (PT_REGS_SYSCALL_RET(regs)) {
 40		case -ERESTART_RESTARTBLOCK:
 41		case -ERESTARTNOHAND:
 42			PT_REGS_SYSCALL_RET(regs) = -EINTR;
 43			break;
 44
 45		case -ERESTARTSYS:
 46			if (!(ka->sa.sa_flags & SA_RESTART)) {
 47				PT_REGS_SYSCALL_RET(regs) = -EINTR;
 48				break;
 49			}
 50		/* fallthrough */
 51		case -ERESTARTNOINTR:
 52			PT_REGS_RESTART_SYSCALL(regs);
 53			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
 54			break;
 55		}
 56	}
 57
 58	sp = PT_REGS_SP(regs);
 59	if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
 60		sp = current->sas_ss_sp + current->sas_ss_size;
 61
 62#ifdef CONFIG_ARCH_HAS_SC_SIGNALS
 63	if (!(ka->sa.sa_flags & SA_SIGINFO))
 64		err = setup_signal_stack_sc(sp, signr, ka, regs, oldset);
 65	else
 66#endif
 67		err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
 68
 69	if (err) {
 70		spin_lock_irq(&current->sighand->siglock);
 71		current->blocked = *oldset;
 72		recalc_sigpending();
 73		spin_unlock_irq(&current->sighand->siglock);
 74		force_sigsegv(signr, current);
 75	} else {
 76		spin_lock_irq(&current->sighand->siglock);
 77		sigorsets(&current->blocked, &current->blocked,
 78			  &ka->sa.sa_mask);
 79		if (!(ka->sa.sa_flags & SA_NODEFER))
 80			sigaddset(&current->blocked, signr);
 81		recalc_sigpending();
 82		spin_unlock_irq(&current->sighand->siglock);
 83	}
 84
 85	return err;
 86}
 87
 88static int kern_do_signal(struct pt_regs *regs)
 89{
 90	struct k_sigaction ka_copy;
 91	siginfo_t info;
 92	sigset_t *oldset;
 93	int sig, handled_sig = 0;
 94
 95	if (test_thread_flag(TIF_RESTORE_SIGMASK))
 96		oldset = &current->saved_sigmask;
 97	else
 98		oldset = &current->blocked;
 99
100	while ((sig = get_signal_to_deliver(&info, &ka_copy, regs, NULL)) > 0) {
101		handled_sig = 1;
102		/* Whee!  Actually deliver the signal.  */
103		if (!handle_signal(regs, sig, &ka_copy, &info, oldset)) {
104			/*
105			 * a signal was successfully delivered; the saved
106			 * sigmask will have been stored in the signal frame,
107			 * and will be restored by sigreturn, so we can simply
108			 * clear the TIF_RESTORE_SIGMASK flag
109			 */
110			if (test_thread_flag(TIF_RESTORE_SIGMASK))
111				clear_thread_flag(TIF_RESTORE_SIGMASK);
112			break;
113		}
114	}
115
116	/* Did we come from a system call? */
117	if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
118		/* Restart the system call - no handlers present */
119		switch (PT_REGS_SYSCALL_RET(regs)) {
120		case -ERESTARTNOHAND:
121		case -ERESTARTSYS:
122		case -ERESTARTNOINTR:
123			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
124			PT_REGS_RESTART_SYSCALL(regs);
125			break;
126		case -ERESTART_RESTARTBLOCK:
127			PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
128			PT_REGS_RESTART_SYSCALL(regs);
129			break;
130		}
131	}
132
133	/*
134	 * This closes a way to execute a system call on the host.  If
135	 * you set a breakpoint on a system call instruction and singlestep
136	 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
137	 * rather than PTRACE_SYSCALL it, allowing the system call to execute
138	 * on the host.  The tracing thread will check this flag and
139	 * PTRACE_SYSCALL if necessary.
140	 */
141	if (current->ptrace & PT_DTRACE)
142		current->thread.singlestep_syscall =
143			is_syscall(PT_REGS_IP(&current->thread.regs));
144
145	/*
146	 * if there's no signal to deliver, we just put the saved sigmask
147	 * back
148	 */
149	if (!handled_sig && test_thread_flag(TIF_RESTORE_SIGMASK)) {
150		clear_thread_flag(TIF_RESTORE_SIGMASK);
151		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
152	}
153	return handled_sig;
154}
155
156int do_signal(void)
157{
158	return kern_do_signal(&current->thread.regs);
159}
160
161/*
162 * Atomically swap in the new signal mask, and wait for a signal.
163 */
164long sys_sigsuspend(int history0, int history1, old_sigset_t mask)
165{
166	mask &= _BLOCKABLE;
167	spin_lock_irq(&current->sighand->siglock);
168	current->saved_sigmask = current->blocked;
169	siginitset(&current->blocked, mask);
170	recalc_sigpending();
171	spin_unlock_irq(&current->sighand->siglock);
172
173	current->state = TASK_INTERRUPTIBLE;
174	schedule();
175	set_thread_flag(TIF_RESTORE_SIGMASK);
176	return -ERESTARTNOHAND;
177}
178
179long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
180{
181	return do_sigaltstack(uss, uoss, PT_REGS_SP(&current->thread.regs));
182}