1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/signal.h>
4 #include <linux/uaccess.h>
5 #include <linux/syscalls.h>
6 #include <linux/tracehook.h>
9 #include <asm/ucontext.h>
12 #include <abi/regdef.h>
14 #ifdef CONFIG_CPU_HAS_FPU
16 static int restore_fpu_state(struct sigcontext __user *sc)
19 struct user_fp user_fp;
21 err = __copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
23 restore_from_user_fp(&user_fp);
28 static int save_fpu_state(struct sigcontext __user *sc)
30 struct user_fp user_fp;
32 save_to_user_fp(&user_fp);
34 return __copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
37 #define restore_fpu_state(sigcontext) (0)
38 #define save_fpu_state(sigcontext) (0)
43 * pad[3] is compatible with the same struct defined in
44 * gcc/libgcc/config/csky/linux-unwind.h
51 static long restore_sigcontext(struct pt_regs *regs,
52 struct sigcontext __user *sc)
56 /* sc_pt_regs is structured the same as the start of pt_regs */
57 err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
59 /* Restore the floating-point state. */
60 err |= restore_fpu_state(sc);
65 SYSCALL_DEFINE0(rt_sigreturn)
67 struct pt_regs *regs = current_pt_regs();
68 struct rt_sigframe __user *frame;
71 /* Always make any pending restarted system calls return -EINTR */
72 current->restart_block.fn = do_no_restart_syscall;
74 frame = (struct rt_sigframe __user *)regs->usp;
76 if (!access_ok(frame, sizeof(*frame)))
79 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
82 set_current_blocked(&set);
84 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
87 if (restore_altstack(&frame->uc.uc_stack))
97 static int setup_sigcontext(struct rt_sigframe __user *frame,
100 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
103 err |= __copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
104 err |= save_fpu_state(sc);
109 static inline void __user *get_sigframe(struct ksignal *ksig,
110 struct pt_regs *regs, size_t framesize)
113 /* Default to using normal stack */
117 * If we are on the alternate signal stack and would overflow it, don't.
118 * Return an always-bogus address instead so we will die with SIGSEGV.
120 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
121 return (void __user __force *)(-1UL);
123 /* This is the X/Open sanctioned signal stack switching. */
124 sp = sigsp(sp, ksig) - framesize;
126 /* Align the stack frame. */
129 return (void __user *)sp;
133 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
135 struct rt_sigframe *frame;
137 struct csky_vdso *vdso = current->mm->context.vdso;
139 frame = get_sigframe(ksig, regs, sizeof(*frame));
140 if (!access_ok(frame, sizeof(*frame)))
143 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
145 /* Create the ucontext. */
146 err |= __put_user(0, &frame->uc.uc_flags);
147 err |= __put_user(NULL, &frame->uc.uc_link);
148 err |= __save_altstack(&frame->uc.uc_stack, regs->usp);
149 err |= setup_sigcontext(frame, regs);
150 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
154 /* Set up to return from userspace. */
155 regs->lr = (unsigned long)(vdso->rt_signal_retcode);
158 * Set up registers for signal handler.
159 * Registers that we don't modify keep the value they had from
160 * user-space at the time we took the signal.
161 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
162 * since some things rely on this (e.g. glibc's debug/segfault.c).
164 regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
165 regs->usp = (unsigned long)frame;
166 regs->a0 = ksig->sig; /* a0: signal number */
167 regs->a1 = (unsigned long)(&(frame->info)); /* a1: siginfo pointer */
168 regs->a2 = (unsigned long)(&(frame->uc)); /* a2: ucontext pointer */
173 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
175 sigset_t *oldset = sigmask_to_save();
178 /* Are we from a system call? */
179 if (in_syscall(regs)) {
180 /* Avoid additional syscall restarting via ret_from_exception */
181 forget_syscall(regs);
183 /* If so, check system call restarting.. */
185 case -ERESTART_RESTARTBLOCK:
186 case -ERESTARTNOHAND:
191 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
196 case -ERESTARTNOINTR:
197 regs->a0 = regs->orig_a0;
198 regs->pc -= TRAP0_SIZE;
203 /* Set up the stack frame */
204 ret = setup_rt_frame(ksig, oldset, regs);
206 signal_setup_done(ret, ksig, 0);
209 static void do_signal(struct pt_regs *regs)
213 if (get_signal(&ksig)) {
214 /* Actually deliver the signal */
215 handle_signal(&ksig, regs);
219 /* Did we come from a system call? */
220 if (in_syscall(regs)) {
221 /* Avoid additional syscall restarting via ret_from_exception */
222 forget_syscall(regs);
224 /* Restart the system call - no handlers present */
226 case -ERESTARTNOHAND:
228 case -ERESTARTNOINTR:
229 regs->a0 = regs->orig_a0;
230 regs->pc -= TRAP0_SIZE;
232 case -ERESTART_RESTARTBLOCK:
233 regs->a0 = regs->orig_a0;
234 regs_syscallid(regs) = __NR_restart_syscall;
235 regs->pc -= TRAP0_SIZE;
241 * If there is no signal to deliver, we just put the saved
244 restore_saved_sigmask();
248 * notification of userspace execution resumption
249 * - triggered by the _TIF_WORK_MASK flags
251 asmlinkage void do_notify_resume(struct pt_regs *regs,
252 unsigned long thread_info_flags)
254 /* Handle pending signal delivery */
255 if (thread_info_flags & _TIF_SIGPENDING)
258 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
259 clear_thread_flag(TIF_NOTIFY_RESUME);
260 tracehook_notify_resume(regs);