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)
55 unsigned long sr = regs->sr;
57 /* sc_pt_regs is structured the same as the start of pt_regs */
58 err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
60 /* BIT(0) of regs->sr is Condition Code/Carry bit */
61 regs->sr = (sr & ~1) | (regs->sr & 1);
63 /* Restore the floating-point state. */
64 err |= restore_fpu_state(sc);
69 SYSCALL_DEFINE0(rt_sigreturn)
71 struct pt_regs *regs = current_pt_regs();
72 struct rt_sigframe __user *frame;
75 /* Always make any pending restarted system calls return -EINTR */
76 current->restart_block.fn = do_no_restart_syscall;
78 frame = (struct rt_sigframe __user *)regs->usp;
80 if (!access_ok(frame, sizeof(*frame)))
83 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
86 set_current_blocked(&set);
88 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
91 if (restore_altstack(&frame->uc.uc_stack))
101 static int setup_sigcontext(struct rt_sigframe __user *frame,
102 struct pt_regs *regs)
104 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
107 err |= __copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
108 err |= save_fpu_state(sc);
113 static inline void __user *get_sigframe(struct ksignal *ksig,
114 struct pt_regs *regs, size_t framesize)
117 /* Default to using normal stack */
121 * If we are on the alternate signal stack and would overflow it, don't.
122 * Return an always-bogus address instead so we will die with SIGSEGV.
124 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
125 return (void __user __force *)(-1UL);
127 /* This is the X/Open sanctioned signal stack switching. */
128 sp = sigsp(sp, ksig) - framesize;
130 /* Align the stack frame. */
133 return (void __user *)sp;
137 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
139 struct rt_sigframe __user *frame;
141 struct csky_vdso *vdso = current->mm->context.vdso;
143 frame = get_sigframe(ksig, regs, sizeof(*frame));
144 if (!access_ok(frame, sizeof(*frame)))
147 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
149 /* Create the ucontext. */
150 err |= __put_user(0, &frame->uc.uc_flags);
151 err |= __put_user(NULL, &frame->uc.uc_link);
152 err |= __save_altstack(&frame->uc.uc_stack, regs->usp);
153 err |= setup_sigcontext(frame, regs);
154 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
158 /* Set up to return from userspace. */
159 regs->lr = (unsigned long)(vdso->rt_signal_retcode);
162 * Set up registers for signal handler.
163 * Registers that we don't modify keep the value they had from
164 * user-space at the time we took the signal.
165 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
166 * since some things rely on this (e.g. glibc's debug/segfault.c).
168 regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
169 regs->usp = (unsigned long)frame;
170 regs->a0 = ksig->sig; /* a0: signal number */
171 regs->a1 = (unsigned long)(&(frame->info)); /* a1: siginfo pointer */
172 regs->a2 = (unsigned long)(&(frame->uc)); /* a2: ucontext pointer */
177 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
179 sigset_t *oldset = sigmask_to_save();
182 rseq_signal_deliver(ksig, regs);
184 /* Are we from a system call? */
185 if (in_syscall(regs)) {
186 /* Avoid additional syscall restarting via ret_from_exception */
187 forget_syscall(regs);
189 /* If so, check system call restarting.. */
191 case -ERESTART_RESTARTBLOCK:
192 case -ERESTARTNOHAND:
197 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
202 case -ERESTARTNOINTR:
203 regs->a0 = regs->orig_a0;
204 regs->pc -= TRAP0_SIZE;
209 /* Set up the stack frame */
210 ret = setup_rt_frame(ksig, oldset, regs);
212 signal_setup_done(ret, ksig, 0);
215 static void do_signal(struct pt_regs *regs)
219 if (get_signal(&ksig)) {
220 /* Actually deliver the signal */
221 handle_signal(&ksig, regs);
225 /* Did we come from a system call? */
226 if (in_syscall(regs)) {
227 /* Avoid additional syscall restarting via ret_from_exception */
228 forget_syscall(regs);
230 /* Restart the system call - no handlers present */
232 case -ERESTARTNOHAND:
234 case -ERESTARTNOINTR:
235 regs->a0 = regs->orig_a0;
236 regs->pc -= TRAP0_SIZE;
238 case -ERESTART_RESTARTBLOCK:
239 regs->a0 = regs->orig_a0;
240 regs_syscallid(regs) = __NR_restart_syscall;
241 regs->pc -= TRAP0_SIZE;
247 * If there is no signal to deliver, we just put the saved
250 restore_saved_sigmask();
254 * notification of userspace execution resumption
255 * - triggered by the _TIF_WORK_MASK flags
257 asmlinkage void do_notify_resume(struct pt_regs *regs,
258 unsigned long thread_info_flags)
260 if (thread_info_flags & _TIF_UPROBE)
261 uprobe_notify_resume(regs);
263 /* Handle pending signal delivery */
264 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
267 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
268 tracehook_notify_resume(regs);
269 rseq_handle_notify_resume(NULL, regs);