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2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376 
 kernel/arch/riscv/kernel/signal.c
....@@ -1,22 +1,9 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
34  *  Chen Liqin <liqin.chen@sunplusct.com>
45  *  Lennox Wu <lennox.wu@sunplusct.com>
56  * Copyright (C) 2012 Regents of the University of California
6
- *
7
- * This program is free software; you can redistribute it and/or modify
8
- * it under the terms of the GNU General Public License as published by
9
- * the Free Software Foundation; either version 2 of the License, or
10
- * (at your option) any later version.
11
- *
12
- * This program is distributed in the hope that it will be useful,
13
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
14
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15
- * GNU General Public License for more details.
16
- *
17
- * You should have received a copy of the GNU General Public License
18
- * along with this program; if not, see the file COPYING, or write
19
- * to the Free Software Foundation, Inc.,
207  */
218 
229 #include <linux/signal.h>
....@@ -30,52 +17,81 @@
3017 #include <asm/switch_to.h>
3118 #include <asm/csr.h>
3219 
20
+extern u32 __user_rt_sigreturn[2];
21
+
3322 #define DEBUG_SIG 0
3423 
3524 struct rt_sigframe {
3625 	struct siginfo info;
3726 	struct ucontext uc;
27
+#ifndef CONFIG_MMU
28
+	u32 sigreturn_code[2];
29
+#endif
3830 };
3931 
40
-static long restore_d_state(struct pt_regs *regs,
41
-	struct __riscv_d_ext_state __user *state)
32
+#ifdef CONFIG_FPU
33
+static long restore_fp_state(struct pt_regs *regs,
34
+			     union __riscv_fp_state __user *sc_fpregs)
4235 {
4336 	long err;
44
-	err = __copy_from_user(&current->thread.fstate, state, sizeof(*state));
45
-	if (likely(!err))
46
-		fstate_restore(current, regs);
47
-	return err;
48
-}
49
-
50
-static long save_d_state(struct pt_regs *regs,
51
-	struct __riscv_d_ext_state __user *state)
52
-{
53
-	fstate_save(current, regs);
54
-	return __copy_to_user(state, &current->thread.fstate, sizeof(*state));
55
-}
56
-
57
-static long restore_sigcontext(struct pt_regs *regs,
58
-	struct sigcontext __user *sc)
59
-{
60
-	long err;
37
+	struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
6138 	size_t i;
62
-	/* sc_regs is structured the same as the start of pt_regs */
63
-	err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs));
39
+
40
+	err = __copy_from_user(&current->thread.fstate, state, sizeof(*state));
6441 	if (unlikely(err))
6542 		return err;
66
-	/* Restore the floating-point state. */
67
-	err = restore_d_state(regs, &sc->sc_fpregs.d);
68
-	if (unlikely(err))
69
-		return err;
43
+
44
+	fstate_restore(current, regs);
45
+
7046 	/* We support no other extension state at this time. */
71
-	for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++) {
47
+	for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
7248 		u32 value;
73
-		err = __get_user(value, &sc->sc_fpregs.q.reserved[i]);
49
+
50
+		err = __get_user(value, &sc_fpregs->q.reserved[i]);
7451 		if (unlikely(err))
7552 			break;
7653 		if (value != 0)
7754 			return -EINVAL;
7855 	}
56
+
57
+	return err;
58
+}
59
+
60
+static long save_fp_state(struct pt_regs *regs,
61
+			  union __riscv_fp_state __user *sc_fpregs)
62
+{
63
+	long err;
64
+	struct __riscv_d_ext_state __user *state = &sc_fpregs->d;
65
+	size_t i;
66
+
67
+	fstate_save(current, regs);
68
+	err = __copy_to_user(state, &current->thread.fstate, sizeof(*state));
69
+	if (unlikely(err))
70
+		return err;
71
+
72
+	/* We support no other extension state at this time. */
73
+	for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) {
74
+		err = __put_user(0, &sc_fpregs->q.reserved[i]);
75
+		if (unlikely(err))
76
+			break;
77
+	}
78
+
79
+	return err;
80
+}
81
+#else
82
+#define save_fp_state(task, regs) (0)
83
+#define restore_fp_state(task, regs) (0)
84
+#endif
85
+
86
+static long restore_sigcontext(struct pt_regs *regs,
87
+	struct sigcontext __user *sc)
88
+{
89
+	long err;
90
+	/* sc_regs is structured the same as the start of pt_regs */
91
+	err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs));
92
+	/* Restore the floating-point state. */
93
+	if (has_fpu)
94
+		err |= restore_fp_state(regs, &sc->sc_fpregs);
7995 	return err;
8096 }
8197 
....@@ -91,7 +107,7 @@
91107 
92108 	frame = (struct rt_sigframe __user *)regs->sp;
93109 
94
-	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
110
+	if (!access_ok(frame, sizeof(*frame)))
95111 		goto badframe;
96112 
97113 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
....@@ -105,6 +121,8 @@
105121 	if (restore_altstack(&frame->uc.uc_stack))
106122 		goto badframe;
107123 
124
+	regs->cause = -1UL;
125
+
108126 	return regs->a0;
109127 
110128 badframe:
....@@ -113,9 +131,9 @@
113131 		pr_info_ratelimited(
114132 			"%s[%d]: bad frame in %s: frame=%p pc=%p sp=%p\n",
115133 			task->comm, task_pid_nr(task), __func__,
116
-			frame, (void *)regs->sepc, (void *)regs->sp);
134
+			frame, (void *)regs->epc, (void *)regs->sp);
117135 	}
118
-	force_sig(SIGSEGV, task);
136
+	force_sig(SIGSEGV);
119137 	return 0;
120138 }
121139 
....@@ -124,14 +142,11 @@
124142 {
125143 	struct sigcontext __user *sc = &frame->uc.uc_mcontext;
126144 	long err;
127
-	size_t i;
128145 	/* sc_regs is structured the same as the start of pt_regs */
129146 	err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs));
130147 	/* Save the floating-point state. */
131
-	err |= save_d_state(regs, &sc->sc_fpregs.d);
132
-	/* We support no other extension state at this time. */
133
-	for (i = 0; i < ARRAY_SIZE(sc->sc_fpregs.q.reserved); i++)
134
-		err |= __put_user(0, &sc->sc_fpregs.q.reserved[i]);
148
+	if (has_fpu)
149
+		err |= save_fp_state(regs, &sc->sc_fpregs);
135150 	return err;
136151 }
137152 
....@@ -158,7 +173,6 @@
158173 	return (void __user *)sp;
159174 }
160175 
161
-
162176 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
163177 	struct pt_regs *regs)
164178 {
....@@ -166,7 +180,7 @@
166180 	long err = 0;
167181 
168182 	frame = get_sigframe(ksig, regs, sizeof(*frame));
169
-	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
183
+	if (!access_ok(frame, sizeof(*frame)))
170184 		return -EFAULT;
171185 
172186 	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
....@@ -181,8 +195,19 @@
181195 		return -EFAULT;
182196 
183197 	/* Set up to return from userspace. */
198
+#ifdef CONFIG_MMU
184199 	regs->ra = (unsigned long)VDSO_SYMBOL(
185200 		current->mm->context.vdso, rt_sigreturn);
201
+#else
202
+	/*
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.
205
+	 */
206
+	if (copy_to_user(&frame->sigreturn_code, __user_rt_sigreturn,
207
+			 sizeof(frame->sigreturn_code)))
208
+		return -EFAULT;
209
+	regs->ra = (unsigned long)&frame->sigreturn_code;
210
+#endif /* CONFIG_MMU */
186211 
187212 	/*
188213 	 * Set up registers for signal handler.
....@@ -191,7 +216,7 @@
191216 	 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
192217 	 * since some things rely on this (e.g. glibc's debug/segfault.c).
193218 	 */
194
-	regs->sepc = (unsigned long)ksig->ka.sa.sa_handler;
219
+	regs->epc = (unsigned long)ksig->ka.sa.sa_handler;
195220 	regs->sp = (unsigned long)frame;
196221 	regs->a0 = ksig->sig;                     /* a0: signal number */
197222 	regs->a1 = (unsigned long)(&frame->info); /* a1: siginfo pointer */
....@@ -200,7 +225,7 @@
200225 #if DEBUG_SIG
201226 	pr_info("SIG deliver (%s:%d): sig=%d pc=%p ra=%p sp=%p\n",
202227 		current->comm, task_pid_nr(current), ksig->sig,
203
-		(void *)regs->sepc, (void *)regs->ra, frame);
228
+		(void *)regs->epc, (void *)regs->ra, frame);
204229 #endif
205230 
206231 	return 0;
....@@ -212,7 +237,9 @@
212237 	int ret;
213238 
214239 	/* Are we from a system call? */
215
-	if (regs->scause == EXC_SYSCALL) {
240
+	if (regs->cause == EXC_SYSCALL) {
241
+		/* Avoid additional syscall restarting via ret_from_exception */
242
+		regs->cause = -1UL;
216243 		/* If so, check system call restarting.. */
217244 		switch (regs->a0) {
218245 		case -ERESTART_RESTARTBLOCK:
....@@ -225,10 +252,10 @@
225252 				regs->a0 = -EINTR;
226253 				break;
227254 			}
228
-			/* fallthrough */
255
+			fallthrough;
229256 		case -ERESTARTNOINTR:
230257                         regs->a0 = regs->orig_a0;
231
-			regs->sepc -= 0x4;
258
+			regs->epc -= 0x4;
232259 			break;
233260 		}
234261 	}
....@@ -250,19 +277,22 @@
250277 	}
251278 
252279 	/* Did we come from a system call? */
253
-	if (regs->scause == EXC_SYSCALL) {
280
+	if (regs->cause == EXC_SYSCALL) {
281
+		/* Avoid additional syscall restarting via ret_from_exception */
282
+		regs->cause = -1UL;
283
+
254284 		/* Restart the system call - no handlers present */
255285 		switch (regs->a0) {
256286 		case -ERESTARTNOHAND:
257287 		case -ERESTARTSYS:
258288 		case -ERESTARTNOINTR:
259289                         regs->a0 = regs->orig_a0;
260
-			regs->sepc -= 0x4;
290
+			regs->epc -= 0x4;
261291 			break;
262292 		case -ERESTART_RESTARTBLOCK:
263293                         regs->a0 = regs->orig_a0;
264294 			regs->a7 = __NR_restart_syscall;
265
-			regs->sepc -= 0x4;
295
+			regs->epc -= 0x4;
266296 			break;
267297 		}
268298 	}
....@@ -278,15 +308,13 @@
278308  * notification of userspace execution resumption
279309  * - triggered by the _TIF_WORK_MASK flags
280310  */
281
-asmlinkage void do_notify_resume(struct pt_regs *regs,
282
-	unsigned long thread_info_flags)
311
+asmlinkage __visible void do_notify_resume(struct pt_regs *regs,
312
+					   unsigned long thread_info_flags)
283313 {
284314 	/* Handle pending signal delivery */
285
-	if (thread_info_flags & _TIF_SIGPENDING)
315
+	if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
286316 		do_signal(regs);
287317 
288
-	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
289
-		clear_thread_flag(TIF_NOTIFY_RESUME);
318
+	if (thread_info_flags & _TIF_NOTIFY_RESUME)
290319 		tracehook_notify_resume(regs);
291
-	}
292320 }