1 // SPDX-License-Identifier: GPL-2.0-or-later
3 #include <linux/compat.h>
4 #include <linux/signal.h>
5 #include <linux/uaccess.h>
6 #include <linux/syscalls.h>
7 #include <linux/linkage.h>
10 #include <asm/signal32.h>
11 #include <asm/switch_to.h>
12 #include <asm/ucontext.h>
15 #define COMPAT_DEBUG_SIG 0
17 struct compat_sigcontext {
18 struct compat_user_regs_struct sc_regs;
19 union __riscv_fp_state sc_fpregs;
22 struct compat_ucontext {
23 compat_ulong_t uc_flags;
24 struct compat_ucontext *uc_link;
25 compat_stack_t uc_stack;
27 /* There's some padding here to allow sigset_t to be expanded in the
28 * future. Though this is unlikely, other architectures put uc_sigmask
29 * at the end of this structure and explicitly state it can be
30 * expanded, so we didn't want to box ourselves in here. */
31 __u8 __unused[1024 / 8 - sizeof(sigset_t)];
32 /* We can't put uc_sigmask at the end of this structure because we need
33 * to be able to expand sigcontext in the future. For example, the
34 * vector ISA extension will almost certainly add ISA state. We want
35 * to ensure all user-visible ISA state can be saved and restored via a
36 * ucontext, so we're putting this at the end in order to allow for
37 * infinite extensibility. Since we know this will be extended and we
38 * assume sigset_t won't be extended an extreme amount, we're
39 * prioritizing this. */
40 struct compat_sigcontext uc_mcontext;
43 struct compat_rt_sigframe {
44 struct compat_siginfo info;
45 struct compat_ucontext uc;
49 static long compat_restore_fp_state(struct pt_regs *regs,
50 union __riscv_fp_state __user *sc_fpregs)
53 struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
56 err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state));
60 fstate_restore(current, regs);
62 /* We support no other extension state at this time. */
63 for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
66 err = __get_user(value, &sc_fpregs->q.reserved[i]);
76 static long compat_save_fp_state(struct pt_regs *regs,
77 union __riscv_fp_state __user *sc_fpregs)
80 struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
83 fstate_save(current, regs);
84 err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state));
88 /* We support no other extension state at this time. */
89 for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
90 err = __put_user(0, &sc_fpregs->q.reserved[i]);
98 #define compat_save_fp_state(task, regs) (0)
99 #define compat_restore_fp_state(task, regs) (0)
102 static long compat_restore_sigcontext(struct pt_regs *regs,
103 struct compat_sigcontext __user *sc)
106 struct compat_user_regs_struct cregs;
108 /* sc_regs is structured the same as the start of pt_regs */
109 err = __copy_from_user(&cregs, &sc->sc_regs, sizeof(sc->sc_regs));
111 cregs_to_regs(&cregs, regs);
113 /* Restore the floating-point state. */
115 err |= compat_restore_fp_state(regs, &sc->sc_fpregs);
119 COMPAT_SYSCALL_DEFINE0(rt_sigreturn)
121 struct pt_regs *regs = current_pt_regs();
122 struct compat_rt_sigframe __user *frame;
123 struct task_struct *task;
126 /* Always make any pending restarted system calls return -EINTR */
127 current->restart_block.fn = do_no_restart_syscall;
129 frame = (struct compat_rt_sigframe __user *)regs->sp;
131 if (!access_ok(frame, sizeof(*frame)))
134 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
137 set_current_blocked(&set);
139 if (compat_restore_sigcontext(regs, &frame->uc.uc_mcontext))
142 if (compat_restore_altstack(&frame->uc.uc_stack))
149 if (show_unhandled_signals) {
151 "%s[%d]: bad frame in %s: frame=%p pc=%p sp=%p\n",
152 task->comm, task_pid_nr(task), __func__,
153 frame, (void *)regs->epc, (void *)regs->sp);
159 static long compat_setup_sigcontext(struct compat_rt_sigframe __user *frame,
160 struct pt_regs *regs)
162 struct compat_sigcontext __user *sc = &frame->uc.uc_mcontext;
163 struct compat_user_regs_struct cregs;
166 regs_to_cregs(&cregs, regs);
168 /* sc_regs is structured the same as the start of pt_regs */
169 err = __copy_to_user(&sc->sc_regs, &cregs, sizeof(sc->sc_regs));
170 /* Save the floating-point state. */
172 err |= compat_save_fp_state(regs, &sc->sc_fpregs);
176 static inline void __user *compat_get_sigframe(struct ksignal *ksig,
177 struct pt_regs *regs, size_t framesize)
180 /* Default to using normal stack */
184 * If we are on the alternate signal stack and would overflow it, don't.
185 * Return an always-bogus address instead so we will die with SIGSEGV.
187 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
188 return (void __user __force *)(-1UL);
190 /* This is the X/Open sanctioned signal stack switching. */
191 sp = sigsp(sp, ksig) - framesize;
193 /* Align the stack frame. */
196 return (void __user *)sp;
199 int compat_setup_rt_frame(struct ksignal *ksig, sigset_t *set,
200 struct pt_regs *regs)
202 struct compat_rt_sigframe __user *frame;
205 frame = compat_get_sigframe(ksig, regs, sizeof(*frame));
206 if (!access_ok(frame, sizeof(*frame)))
209 err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
211 /* Create the ucontext. */
212 err |= __put_user(0, &frame->uc.uc_flags);
213 err |= __put_user(NULL, &frame->uc.uc_link);
214 err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
215 err |= compat_setup_sigcontext(frame, regs);
216 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
220 regs->ra = (unsigned long)COMPAT_VDSO_SYMBOL(
221 current->mm->context.vdso, rt_sigreturn);
224 * Set up registers for signal handler.
225 * Registers that we don't modify keep the value they had from
226 * user-space at the time we took the signal.
227 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
228 * since some things rely on this (e.g. glibc's debug/segfault.c).
230 regs->epc = (unsigned long)ksig->ka.sa.sa_handler;
231 regs->sp = (unsigned long)frame;
232 regs->a0 = ksig->sig; /* a0: signal number */
233 regs->a1 = (unsigned long)(&frame->info); /* a1: siginfo pointer */
234 regs->a2 = (unsigned long)(&frame->uc); /* a2: ucontext pointer */
237 pr_info("SIG deliver (%s:%d): sig=%d pc=%p ra=%p sp=%p\n",
238 current->comm, task_pid_nr(current), ksig->sig,
239 (void *)regs->epc, (void *)regs->ra, frame);