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#include <asm/syscalls.h>
23
24#include "signal-common.h"
25
26/*
27 * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
28 */
29#define __NR_O32_restart_syscall 4253
30
31struct sigframe32 {
32 u32 sf_ass[4]; /* argument save space for o32 */
33 u32 sf_pad[2]; /* Was: signal trampoline */
34 struct sigcontext32 sf_sc;
35 compat_sigset_t sf_mask;
36};
37
38struct ucontext32 {
39 u32 uc_flags;
40 s32 uc_link;
41 compat_stack_t uc_stack;
42 struct sigcontext32 uc_mcontext;
43 compat_sigset_t uc_sigmask; /* mask last for extensibility */
44};
45
46struct rt_sigframe32 {
47 u32 rs_ass[4]; /* argument save space for o32 */
48 u32 rs_pad[2]; /* Was: signal trampoline */
49 compat_siginfo_t rs_info;
50 struct ucontext32 rs_uc;
51};
52
53static int setup_sigcontext32(struct pt_regs *regs,
54 struct sigcontext32 __user *sc)
55{
56 int err = 0;
57 int i;
58
59 err |= __put_user(regs->cp0_epc, &sc->sc_pc);
60
61 err |= __put_user(0, &sc->sc_regs[0]);
62 for (i = 1; i < 32; i++)
63 err |= __put_user(regs->regs[i], &sc->sc_regs[i]);
64
65 err |= __put_user(regs->hi, &sc->sc_mdhi);
66 err |= __put_user(regs->lo, &sc->sc_mdlo);
67 if (cpu_has_dsp) {
68 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
69 err |= __put_user(mfhi1(), &sc->sc_hi1);
70 err |= __put_user(mflo1(), &sc->sc_lo1);
71 err |= __put_user(mfhi2(), &sc->sc_hi2);
72 err |= __put_user(mflo2(), &sc->sc_lo2);
73 err |= __put_user(mfhi3(), &sc->sc_hi3);
74 err |= __put_user(mflo3(), &sc->sc_lo3);
75 }
76
77 /*
78 * Save FPU state to signal context. Signal handler
79 * will "inherit" current FPU state.
80 */
81 err |= protected_save_fp_context(sc);
82
83 return err;
84}
85
86static int restore_sigcontext32(struct pt_regs *regs,
87 struct sigcontext32 __user *sc)
88{
89 int err = 0;
90 s32 treg;
91 int i;
92
93 /* Always make any pending restarted system calls return -EINTR */
94 current->restart_block.fn = do_no_restart_syscall;
95
96 err |= __get_user(regs->cp0_epc, &sc->sc_pc);
97 err |= __get_user(regs->hi, &sc->sc_mdhi);
98 err |= __get_user(regs->lo, &sc->sc_mdlo);
99 if (cpu_has_dsp) {
100 err |= __get_user(treg, &sc->sc_hi1); mthi1(treg);
101 err |= __get_user(treg, &sc->sc_lo1); mtlo1(treg);
102 err |= __get_user(treg, &sc->sc_hi2); mthi2(treg);
103 err |= __get_user(treg, &sc->sc_lo2); mtlo2(treg);
104 err |= __get_user(treg, &sc->sc_hi3); mthi3(treg);
105 err |= __get_user(treg, &sc->sc_lo3); mtlo3(treg);
106 err |= __get_user(treg, &sc->sc_dsp); wrdsp(treg, DSP_MASK);
107 }
108
109 for (i = 1; i < 32; i++)
110 err |= __get_user(regs->regs[i], &sc->sc_regs[i]);
111
112 return err ?: protected_restore_fp_context(sc);
113}
114
115static int setup_frame_32(void *sig_return, struct ksignal *ksig,
116 struct pt_regs *regs, sigset_t *set)
117{
118 struct sigframe32 __user *frame;
119 int err = 0;
120
121 frame = get_sigframe(ksig, regs, frame_size: sizeof(*frame));
122 if (!access_ok(frame, sizeof (*frame)))
123 return -EFAULT;
124
125 err |= setup_sigcontext32(regs, sc: &frame->sf_sc);
126 err |= __copy_conv_sigset_to_user(&frame->sf_mask, set);
127
128 if (err)
129 return -EFAULT;
130
131 /*
132 * Arguments to signal handler:
133 *
134 * a0 = signal number
135 * a1 = 0 (should be cause)
136 * a2 = pointer to struct sigcontext
137 *
138 * $25 and c0_epc point to the signal handler, $29 points to the
139 * struct sigframe.
140 */
141 regs->regs[ 4] = ksig->sig;
142 regs->regs[ 5] = 0;
143 regs->regs[ 6] = (unsigned long) &frame->sf_sc;
144 regs->regs[29] = (unsigned long) frame;
145 regs->regs[31] = (unsigned long) sig_return;
146 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
147
148 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
149 current->comm, current->pid,
150 frame, regs->cp0_epc, regs->regs[31]);
151
152 return 0;
153}
154
155asmlinkage void sys32_rt_sigreturn(void)
156{
157 struct rt_sigframe32 __user *frame;
158 struct pt_regs *regs;
159 sigset_t set;
160 int sig;
161
162 regs = current_pt_regs();
163 frame = (struct rt_sigframe32 __user *)regs->regs[29];
164 if (!access_ok(frame, sizeof(*frame)))
165 goto badframe;
166 if (__copy_conv_sigset_from_user(&set, &frame->rs_uc.uc_sigmask))
167 goto badframe;
168
169 set_current_blocked(&set);
170
171 sig = restore_sigcontext32(regs, sc: &frame->rs_uc.uc_mcontext);
172 if (sig < 0)
173 goto badframe;
174 else if (sig)
175 force_sig(sig);
176
177 if (compat_restore_altstack(&frame->rs_uc.uc_stack))
178 goto badframe;
179
180 /*
181 * Don't let your children do this ...
182 */
183 __asm__ __volatile__(
184 "move\t$29, %0\n\t"
185 "j\tsyscall_exit"
186 : /* no outputs */
187 : "r" (regs));
188 /* Unreached */
189
190badframe:
191 force_sig(SIGSEGV);
192}
193
194static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig,
195 struct pt_regs *regs, sigset_t *set)
196{
197 struct rt_sigframe32 __user *frame;
198 int err = 0;
199
200 frame = get_sigframe(ksig, regs, frame_size: sizeof(*frame));
201 if (!access_ok(frame, sizeof (*frame)))
202 return -EFAULT;
203
204 /* Convert (siginfo_t -> compat_siginfo_t) and copy to user. */
205 err |= copy_siginfo_to_user32(&frame->rs_info, &ksig->info);
206
207 /* Create the ucontext. */
208 err |= __put_user(0, &frame->rs_uc.uc_flags);
209 err |= __put_user(0, &frame->rs_uc.uc_link);
210 err |= __compat_save_altstack(&frame->rs_uc.uc_stack, regs->regs[29]);
211 err |= setup_sigcontext32(regs, sc: &frame->rs_uc.uc_mcontext);
212 err |= __copy_conv_sigset_to_user(&frame->rs_uc.uc_sigmask, set);
213
214 if (err)
215 return -EFAULT;
216
217 /*
218 * Arguments to signal handler:
219 *
220 * a0 = signal number
221 * a1 = 0 (should be cause)
222 * a2 = pointer to ucontext
223 *
224 * $25 and c0_epc point to the signal handler, $29 points to
225 * the struct rt_sigframe32.
226 */
227 regs->regs[ 4] = ksig->sig;
228 regs->regs[ 5] = (unsigned long) &frame->rs_info;
229 regs->regs[ 6] = (unsigned long) &frame->rs_uc;
230 regs->regs[29] = (unsigned long) frame;
231 regs->regs[31] = (unsigned long) sig_return;
232 regs->cp0_epc = regs->regs[25] = (unsigned long) ksig->ka.sa.sa_handler;
233
234 DEBUGP("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%lx\n",
235 current->comm, current->pid,
236 frame, regs->cp0_epc, regs->regs[31]);
237
238 return 0;
239}
240
241/*
242 * o32 compatibility on 64-bit kernels, without DSP ASE
243 */
244struct mips_abi mips_abi_32 = {
245 .setup_frame = setup_frame_32,
246 .setup_rt_frame = setup_rt_frame_32,
247 .restart = __NR_O32_restart_syscall,
248
249 .off_sc_fpregs = offsetof(struct sigcontext32, sc_fpregs),
250 .off_sc_fpc_csr = offsetof(struct sigcontext32, sc_fpc_csr),
251 .off_sc_used_math = offsetof(struct sigcontext32, sc_used_math),
252
253 .vdso = &vdso_image_o32,
254};
255
256
257asmlinkage void sys32_sigreturn(void)
258{
259 struct sigframe32 __user *frame;
260 struct pt_regs *regs;
261 sigset_t blocked;
262 int sig;
263
264 regs = current_pt_regs();
265 frame = (struct sigframe32 __user *)regs->regs[29];
266 if (!access_ok(frame, sizeof(*frame)))
267 goto badframe;
268 if (__copy_conv_sigset_from_user(&blocked, &frame->sf_mask))
269 goto badframe;
270
271 set_current_blocked(&blocked);
272
273 sig = restore_sigcontext32(regs, sc: &frame->sf_sc);
274 if (sig < 0)
275 goto badframe;
276 else if (sig)
277 force_sig(sig);
278
279 /*
280 * Don't let your children do this ...
281 */
282 __asm__ __volatile__(
283 "move\t$29, %0\n\t"
284 "j\tsyscall_exit"
285 : /* no outputs */
286 : "r" (regs));
287 /* Unreached */
288
289badframe:
290 force_sig(SIGSEGV);
291}
292

source code of linux/arch/mips/kernel/signal_o32.c