1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
4 * Chen Liqin <liqin.chen@sunplusct.com>
5 * Lennox Wu <lennox.wu@sunplusct.com>
6 * Copyright (C) 2012 Regents of the University of California
9 #include <linux/compat.h>
10 #include <linux/signal.h>
11 #include <linux/uaccess.h>
12 #include <linux/syscalls.h>
13 #include <linux/resume_user_mode.h>
14 #include <linux/linkage.h>
16 #include <asm/ucontext.h>
18 #include <asm/signal32.h>
19 #include <asm/switch_to.h>
22 extern u32 __user_rt_sigreturn[2];
30 u32 sigreturn_code[2];
35 static long restore_fp_state(struct pt_regs *regs,
36 union __riscv_fp_state __user *sc_fpregs)
39 struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
42 err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state));
46 fstate_restore(current, regs);
48 /* We support no other extension state at this time. */
49 for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
52 err = __get_user(value, &sc_fpregs->q.reserved[i]);
62 static long save_fp_state(struct pt_regs *regs,
63 union __riscv_fp_state __user *sc_fpregs)
66 struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
69 fstate_save(current, regs);
70 err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state));
74 /* We support no other extension state at this time. */
75 for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
76 err = __put_user(0, &sc_fpregs->q.reserved[i]);
84 #define save_fp_state(task, regs) (0)
85 #define restore_fp_state(task, regs) (0)
88 static long restore_sigcontext(struct pt_regs *regs,
89 struct sigcontext __user *sc)
92 /* sc_regs is structured the same as the start of pt_regs */
93 err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs));
94 /* Restore the floating-point state. */
96 err |= restore_fp_state(regs, &sc->sc_fpregs);
100 SYSCALL_DEFINE0(rt_sigreturn)
102 struct pt_regs *regs = current_pt_regs();
103 struct rt_sigframe __user *frame;
104 struct task_struct *task;
107 /* Always make any pending restarted system calls return -EINTR */
108 current->restart_block.fn = do_no_restart_syscall;
110 frame = (struct rt_sigframe __user *)regs->sp;
112 if (!access_ok(frame, sizeof(*frame)))
115 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
118 set_current_blocked(&set);
120 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
123 if (restore_altstack(&frame->uc.uc_stack))
130 if (show_unhandled_signals) {
132 "%s[%d]: bad frame in %s: frame=%p pc=%p sp=%p\n",
133 task->comm, task_pid_nr(task), __func__,
134 frame, (void *)regs->epc, (void *)regs->sp);
140 static long setup_sigcontext(struct rt_sigframe __user *frame,
141 struct pt_regs *regs)
143 struct sigcontext __user *sc = &frame->uc.uc_mcontext;
145 /* sc_regs is structured the same as the start of pt_regs */
146 err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs));
147 /* Save the floating-point state. */
149 err |= save_fp_state(regs, &sc->sc_fpregs);
153 static inline void __user *get_sigframe(struct ksignal *ksig,
154 struct pt_regs *regs, size_t framesize)
157 /* Default to using normal stack */
161 * If we are on the alternate signal stack and would overflow it, don't.
162 * Return an always-bogus address instead so we will die with SIGSEGV.
164 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
165 return (void __user __force *)(-1UL);
167 /* This is the X/Open sanctioned signal stack switching. */
168 sp = sigsp(sp, ksig) - framesize;
170 /* Align the stack frame. */
173 return (void __user *)sp;
176 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
177 struct pt_regs *regs)
179 struct rt_sigframe __user *frame;
182 frame = get_sigframe(ksig, regs, sizeof(*frame));
183 if (!access_ok(frame, sizeof(*frame)))
186 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
188 /* Create the ucontext. */
189 err |= __put_user(0, &frame->uc.uc_flags);
190 err |= __put_user(NULL, &frame->uc.uc_link);
191 err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
192 err |= setup_sigcontext(frame, regs);
193 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
197 /* Set up to return from userspace. */
199 regs->ra = (unsigned long)VDSO_SYMBOL(
200 current->mm->context.vdso, rt_sigreturn);
203 * For the nommu case we don't have a VDSO. Instead we push two
204 * instructions to call the rt_sigreturn syscall onto the user stack.
206 if (copy_to_user(&frame->sigreturn_code, __user_rt_sigreturn,
207 sizeof(frame->sigreturn_code)))
209 regs->ra = (unsigned long)&frame->sigreturn_code;
210 #endif /* CONFIG_MMU */
213 * Set up registers for signal handler.
214 * Registers that we don't modify keep the value they had from
215 * user-space at the time we took the signal.
216 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
217 * since some things rely on this (e.g. glibc's debug/segfault.c).
219 regs->epc = (unsigned long)ksig->ka.sa.sa_handler;
220 regs->sp = (unsigned long)frame;
221 regs->a0 = ksig->sig; /* a0: signal number */
222 regs->a1 = (unsigned long)(&frame->info); /* a1: siginfo pointer */
223 regs->a2 = (unsigned long)(&frame->uc); /* a2: ucontext pointer */
226 pr_info("SIG deliver (%s:%d): sig=%d pc=%p ra=%p sp=%p\n",
227 current->comm, task_pid_nr(current), ksig->sig,
228 (void *)regs->epc, (void *)regs->ra, frame);
234 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
236 sigset_t *oldset = sigmask_to_save();
239 /* Are we from a system call? */
240 if (regs->cause == EXC_SYSCALL) {
241 /* Avoid additional syscall restarting via ret_from_exception */
243 /* If so, check system call restarting.. */
245 case -ERESTART_RESTARTBLOCK:
246 case -ERESTARTNOHAND:
251 if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
256 case -ERESTARTNOINTR:
257 regs->a0 = regs->orig_a0;
263 rseq_signal_deliver(ksig, regs);
265 /* Set up the stack frame */
266 if (is_compat_task())
267 ret = compat_setup_rt_frame(ksig, oldset, regs);
269 ret = setup_rt_frame(ksig, oldset, regs);
271 signal_setup_done(ret, ksig, 0);
274 static void do_signal(struct pt_regs *regs)
278 if (get_signal(&ksig)) {
279 /* Actually deliver the signal */
280 handle_signal(&ksig, regs);
284 /* Did we come from a system call? */
285 if (regs->cause == EXC_SYSCALL) {
286 /* Avoid additional syscall restarting via ret_from_exception */
289 /* Restart the system call - no handlers present */
291 case -ERESTARTNOHAND:
293 case -ERESTARTNOINTR:
294 regs->a0 = regs->orig_a0;
297 case -ERESTART_RESTARTBLOCK:
298 regs->a0 = regs->orig_a0;
299 regs->a7 = __NR_restart_syscall;
306 * If there is no signal to deliver, we just put the saved
309 restore_saved_sigmask();
313 * notification of userspace execution resumption
314 * - triggered by the _TIF_WORK_MASK flags
316 asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
317 unsigned long thread_info_flags)
319 if (thread_info_flags & _TIF_UPROBE)
320 uprobe_notify_resume(regs);
322 /* Handle pending signal delivery */
323 if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
326 if (thread_info_flags & _TIF_NOTIFY_RESUME)
327 resume_user_mode_work(regs);