1 /*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1991, 1992 Linus Torvalds
7 * Copyright (C) 1994 - 2000, 2006 Ralf Baechle
8 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
9 * Copyright (C) 2016, Imagination Technologies Ltd.
10 */
11 #include <linux/compiler.h>
12 #include <linux/errno.h>
13 #include <linux/signal.h>
14 #include <linux/sched/signal.h>
15 #include <linux/uaccess.h>
16
17 #include <asm/abi.h>
18 #include <asm/compat-signal.h>
19 #include <asm/dsp.h>
20 #include <asm/sim.h>
21 #include <asm/unistd.h>
22
23 #include "signal-common.h"
24
25 /*
26 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
27 */
28 #define __NR_O32_restart_syscall 4253
29
30 struct sigframe32 {
31 u32 sf_ass[4]; /* argument save space for o32 */
32 u32 sf_pad[2]; /* Was: signal trampoline */
33 struct sigcontext32 sf_sc;
34 compat_sigset_t sf_mask;
35 };
36
37 struct ucontext32 {
38 u32 uc_flags;
39 s32 uc_link;
40 compat_stack_t uc_stack;
41 struct sigcontext32 uc_mcontext;
42 compat_sigset_t uc_sigmask; /* mask last for extensibility */
43 };
44
45 struct rt_sigframe32 {
46 u32 rs_ass[4]; /* argument save space for o32 */
47 u32 rs_pad[2]; /* Was: signal trampoline */
48 compat_siginfo_t rs_info;
49 struct ucontext32 rs_uc;
50 };
51
setup_sigcontext32(struct pt_regs * regs,struct sigcontext32 __user * sc)52 static int setup_sigcontext32(struct pt_regs *regs,
53 struct sigcontext32 __user *sc)
54 {
55 int err = 0;
56 int i;
57
58 err |= __put_user(regs->cp0_epc, &sc->sc_pc);
59
60 err |= __put_user(0, &sc->sc_regs[0]);
61 for (i = 1; i < 32; i++)
62 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
63
64 err |= __put_user(regs->hi, &sc->sc_mdhi);
65 err |= __put_user(regs->lo, &sc->sc_mdlo);
66 if (cpu_has_dsp) {
67 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
68 err |= __put_user(mfhi1(), &sc->sc_hi1);
69 err |= __put_user(mflo1(), &sc->sc_lo1);
70 err |= __put_user(mfhi2(), &sc->sc_hi2);
71 err |= __put_user(mflo2(), &sc->sc_lo2);
72 err |= __put_user(mfhi3(), &sc->sc_hi3);
73 err |= __put_user(mflo3(), &sc->sc_lo3);
74 }
75
76 /*
77 * Save FPU state to signal context. Signal handler
78 * will "inherit" current FPU state.
79 */
80 err |= protected_save_fp_context(sc);
81
82 return err;
83 }
84
restore_sigcontext32(struct pt_regs * regs,struct sigcontext32 __user * sc)85 static int restore_sigcontext32(struct pt_regs *regs,
86 struct sigcontext32 __user *sc)
87 {
88 int err = 0;
89 s32 treg;
90 int i;
91
92 /* Always make any pending restarted system calls return -EINTR */
93 current->restart_block.fn = do_no_restart_syscall;
94
95 err |= __get_user(regs->cp0_epc, &sc->sc_pc);
96 err |= __get_user(regs->hi, &sc->sc_mdhi);
97 err |= __get_user(regs->lo, &sc->sc_mdlo);
98 if (cpu_has_dsp) {
99 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
100 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
101 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
102 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
103 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
104 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
105 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
106 }
107
108 for (i = 1; i < 32; i++)
109 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
110
111 return err ?: protected_restore_fp_context(sc);
112 }
113
setup_frame_32(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)114 static int setup_frame_32(void *sig_return, struct ksignal *ksig,
115 struct pt_regs *regs, sigset_t *set)
116 {
117 struct sigframe32 __user *frame;
118 int err = 0;
119
120 frame = get_sigframe(ksig, regs, sizeof(*frame));
121 if (!access_ok(frame, sizeof (*frame)))
122 return -EFAULT;
123
124 err |= setup_sigcontext32(regs, &frame->sf_sc);
125 err |= __copy_conv_sigset_to_user(&frame->sf_mask, set);
126
127 if (err)
128 return -EFAULT;
129
130 /*
131 * Arguments to signal handler:
132 *
133 * a0 = signal number
134 * a1 = 0 (should be cause)
135 * a2 = pointer to struct sigcontext
136 *
137 * $25 and c0_epc point to the signal handler, $29 points to the
138 * struct sigframe.
139 */
140 regs->regs[ 4] = ksig->sig;
141 regs->regs[ 5] = 0;
142 regs->regs[ 6] = (unsigned long) &frame->sf_sc;
143 regs->regs[29] = (unsigned long) frame;
144 regs->regs[31] = (unsigned long) sig_return;
145 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
146
147 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
148 current->comm, current->pid,
149 frame, regs->cp0_epc, regs->regs[31]);
150
151 return 0;
152 }
153
sys32_rt_sigreturn(void)154 asmlinkage void sys32_rt_sigreturn(void)
155 {
156 struct rt_sigframe32 __user *frame;
157 struct pt_regs *regs;
158 sigset_t set;
159 int sig;
160
161 regs = current_pt_regs();
162 frame = (struct rt_sigframe32 __user *)regs->regs[29];
163 if (!access_ok(frame, sizeof(*frame)))
164 goto badframe;
165 if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
166 goto badframe;
167
168 set_current_blocked(&set);
169
170 sig = restore_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
171 if (sig < 0)
172 goto badframe;
173 else if (sig)
174 force_sig(sig);
175
176 if (compat_restore_altstack(&frame->rs_uc.uc_stack))
177 goto badframe;
178
179 /*
180 * Don't let your children do this ...
181 */
182 __asm__ __volatile__(
183 "move\t$29, %0\n\t"
184 "j\tsyscall_exit"
185 : /* no outputs */
186 : "r" (regs));
187 /* Unreached */
188
189 badframe:
190 force_sig(SIGSEGV);
191 }
192
setup_rt_frame_32(void * sig_return,struct ksignal * ksig,struct pt_regs * regs,sigset_t * set)193 static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
194 struct pt_regs *regs, sigset_t *set)
195 {
196 struct rt_sigframe32 __user *frame;
197 int err = 0;
198
199 frame = get_sigframe(ksig, regs, sizeof(*frame));
200 if (!access_ok(frame, sizeof (*frame)))
201 return -EFAULT;
202
203 /* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
204 err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
205
206 /* Create the ucontext. */
207 err |= __put_user(0, &frame->rs_uc.uc_flags);
208 err |= __put_user(0, &frame->rs_uc.uc_link);
209 err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
210 err |= setup_sigcontext32(regs, &frame->rs_uc.uc_mcontext);
211 err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
212
213 if (err)
214 return -EFAULT;
215
216 /*
217 * Arguments to signal handler:
218 *
219 * a0 = signal number
220 * a1 = 0 (should be cause)
221 * a2 = pointer to ucontext
222 *
223 * $25 and c0_epc point to the signal handler, $29 points to
224 * the struct rt_sigframe32.
225 */
226 regs->regs[ 4] = ksig->sig;
227 regs->regs[ 5] = (unsigned long) &frame->rs_info;
228 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
229 regs->regs[29] = (unsigned long) frame;
230 regs->regs[31] = (unsigned long) sig_return;
231 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
232
233 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
234 current->comm, current->pid,
235 frame, regs->cp0_epc, regs->regs[31]);
236
237 return 0;
238 }
239
240 /*
241 * o32 compatibility on 64-bit kernels, without DSP ASE
242 */
243 struct mips_abi mips_abi_32 = {
244 .setup_frame = setup_frame_32,
245 .setup_rt_frame = setup_rt_frame_32,
246 .restart = __NR_O32_restart_syscall,
247
248 .off_sc_fpregs = offsetof(struct sigcontext32, sc_fpregs),
249 .off_sc_fpc_csr = offsetof(struct sigcontext32, sc_fpc_csr),
250 .off_sc_used_math = offsetof(struct sigcontext32, sc_used_math),
251
252 .vdso = &vdso_image_o32,
253 };
254
255
sys32_sigreturn(void)256 asmlinkage void sys32_sigreturn(void)
257 {
258 struct sigframe32 __user *frame;
259 struct pt_regs *regs;
260 sigset_t blocked;
261 int sig;
262
263 regs = current_pt_regs();
264 frame = (struct sigframe32 __user *)regs->regs[29];
265 if (!access_ok(frame, sizeof(*frame)))
266 goto badframe;
267 if (__copy_conv_sigset_from_user(&blocked, &frame->sf_mask))
268 goto badframe;
269
270 set_current_blocked(&blocked);
271
272 sig = restore_sigcontext32(regs, &frame->sf_sc);
273 if (sig < 0)
274 goto badframe;
275 else if (sig)
276 force_sig(sig);
277
278 /*
279 * Don't let your children do this ...
280 */
281 __asm__ __volatile__(
282 "move\t$29, %0\n\t"
283 "j\tsyscall_exit"
284 : /* no outputs */
285 : "r" (regs));
286 /* Unreached */
287
288 badframe:
289 force_sig(SIGSEGV);
290 }
291