1 /*
2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
7 *
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
12 * more details.
13 */
14
15 #include <linux/sched.h>
16 #include <linux/mm.h>
17 #include <linux/smp.h>
18 #include <linux/kernel.h>
19 #include <linux/signal.h>
20 #include <linux/errno.h>
21 #include <linux/wait.h>
22 #include <linux/unistd.h>
23 #include <linux/stddef.h>
24 #include <linux/personality.h>
25 #include <linux/suspend.h>
26 #include <linux/ptrace.h>
27 #include <linux/elf.h>
28 #include <linux/compat.h>
29 #include <linux/syscalls.h>
30 #include <linux/uaccess.h>
31 #include <asm/processor.h>
32 #include <asm/ucontext.h>
33 #include <asm/sigframe.h>
34 #include <asm/syscalls.h>
35 #include <asm/vdso.h>
36 #include <arch/interrupts.h>
37
38 struct compat_ucontext {
39 compat_ulong_t uc_flags;
40 compat_uptr_t uc_link;
41 struct compat_sigaltstack uc_stack;
42 struct sigcontext uc_mcontext;
43 sigset_t uc_sigmask; /* mask last for extensibility */
44 };
45
46 struct compat_rt_sigframe {
47 unsigned char save_area[C_ABI_SAVE_AREA_SIZE]; /* caller save area */
48 struct compat_siginfo info;
49 struct compat_ucontext uc;
50 };
51
copy_siginfo_to_user32(struct compat_siginfo __user * to,const siginfo_t * from)52 int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *from)
53 {
54 int err;
55
56 if (!access_ok(VERIFY_WRITE, to, sizeof(struct compat_siginfo)))
57 return -EFAULT;
58
59 /* If you change siginfo_t structure, please make sure that
60 this code is fixed accordingly.
61 It should never copy any pad contained in the structure
62 to avoid security leaks, but must copy the generic
63 3 ints plus the relevant union member. */
64 err = __put_user(from->si_signo, &to->si_signo);
65 err |= __put_user(from->si_errno, &to->si_errno);
66 err |= __put_user((short)from->si_code, &to->si_code);
67
68 if (from->si_code < 0) {
69 err |= __put_user(from->si_pid, &to->si_pid);
70 err |= __put_user(from->si_uid, &to->si_uid);
71 err |= __put_user(from->si_int, &to->si_int);
72 } else {
73 /*
74 * First 32bits of unions are always present:
75 * si_pid === si_band === si_tid === si_addr(LS half)
76 */
77 err |= __put_user(from->_sifields._pad[0],
78 &to->_sifields._pad[0]);
79 switch (from->si_code >> 16) {
80 case __SI_FAULT >> 16:
81 break;
82 case __SI_CHLD >> 16:
83 err |= __put_user(from->si_utime, &to->si_utime);
84 err |= __put_user(from->si_stime, &to->si_stime);
85 err |= __put_user(from->si_status, &to->si_status);
86 /* FALL THROUGH */
87 default:
88 case __SI_KILL >> 16:
89 err |= __put_user(from->si_uid, &to->si_uid);
90 break;
91 case __SI_POLL >> 16:
92 err |= __put_user(from->si_fd, &to->si_fd);
93 break;
94 case __SI_TIMER >> 16:
95 err |= __put_user(from->si_overrun, &to->si_overrun);
96 err |= __put_user(from->si_int, &to->si_int);
97 break;
98 /* This is not generated by the kernel as of now. */
99 case __SI_RT >> 16:
100 case __SI_MESGQ >> 16:
101 err |= __put_user(from->si_uid, &to->si_uid);
102 err |= __put_user(from->si_int, &to->si_int);
103 break;
104 }
105 }
106 return err;
107 }
108
copy_siginfo_from_user32(siginfo_t * to,struct compat_siginfo __user * from)109 int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
110 {
111 int err;
112
113 if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
114 return -EFAULT;
115
116 err = __get_user(to->si_signo, &from->si_signo);
117 err |= __get_user(to->si_errno, &from->si_errno);
118 err |= __get_user(to->si_code, &from->si_code);
119
120 err |= __get_user(to->si_pid, &from->si_pid);
121 err |= __get_user(to->si_uid, &from->si_uid);
122 err |= __get_user(to->si_int, &from->si_int);
123
124 return err;
125 }
126
127 /* The assembly shim for this function arranges to ignore the return value. */
compat_sys_rt_sigreturn(void)128 long compat_sys_rt_sigreturn(void)
129 {
130 struct pt_regs *regs = current_pt_regs();
131 struct compat_rt_sigframe __user *frame =
132 (struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
133 sigset_t set;
134
135 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
136 goto badframe;
137 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
138 goto badframe;
139
140 set_current_blocked(&set);
141
142 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
143 goto badframe;
144
145 if (compat_restore_altstack(&frame->uc.uc_stack))
146 goto badframe;
147
148 return 0;
149
150 badframe:
151 signal_fault("bad sigreturn frame", regs, frame, 0);
152 return 0;
153 }
154
155 /*
156 * Determine which stack to use..
157 */
compat_get_sigframe(struct k_sigaction * ka,struct pt_regs * regs,size_t frame_size)158 static inline void __user *compat_get_sigframe(struct k_sigaction *ka,
159 struct pt_regs *regs,
160 size_t frame_size)
161 {
162 unsigned long sp;
163
164 /* Default to using normal stack */
165 sp = (unsigned long)compat_ptr(regs->sp);
166
167 /*
168 * If we are on the alternate signal stack and would overflow
169 * it, don't. Return an always-bogus address instead so we
170 * will die with SIGSEGV.
171 */
172 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
173 return (void __user __force *)-1UL;
174
175 /* This is the X/Open sanctioned signal stack switching. */
176 if (ka->sa.sa_flags & SA_ONSTACK) {
177 if (sas_ss_flags(sp) == 0)
178 sp = current->sas_ss_sp + current->sas_ss_size;
179 }
180
181 sp -= frame_size;
182 /*
183 * Align the stack pointer according to the TILE ABI,
184 * i.e. so that on function entry (sp & 15) == 0.
185 */
186 sp &= -16UL;
187 return (void __user *) sp;
188 }
189
compat_setup_rt_frame(struct ksignal * ksig,sigset_t * set,struct pt_regs * regs)190 int compat_setup_rt_frame(struct ksignal *ksig, sigset_t *set,
191 struct pt_regs *regs)
192 {
193 unsigned long restorer;
194 struct compat_rt_sigframe __user *frame;
195 int err = 0, sig = ksig->sig;
196
197 frame = compat_get_sigframe(&ksig->ka, regs, sizeof(*frame));
198
199 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
200 goto err;
201
202 /* Always write at least the signal number for the stack backtracer. */
203 if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
204 /* At sigreturn time, restore the callee-save registers too. */
205 err |= copy_siginfo_to_user32(&frame->info, &ksig->info);
206 regs->flags |= PT_FLAGS_RESTORE_REGS;
207 } else {
208 err |= __put_user(ksig->info.si_signo, &frame->info.si_signo);
209 }
210
211 /* Create the ucontext. */
212 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
213 err |= __put_user(0, &frame->uc.uc_flags);
214 err |= __put_user(0, &frame->uc.uc_link);
215 err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
216 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
217 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
218 if (err)
219 goto err;
220
221 restorer = VDSO_SYM(&__vdso_rt_sigreturn);
222 if (ksig->ka.sa.sa_flags & SA_RESTORER)
223 restorer = ptr_to_compat_reg(ksig->ka.sa.sa_restorer);
224
225 /*
226 * Set up registers for signal handler.
227 * Registers that we don't modify keep the value they had from
228 * user-space at the time we took the signal.
229 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
230 * since some things rely on this (e.g. glibc's debug/segfault.c).
231 */
232 regs->pc = ptr_to_compat_reg(ksig->ka.sa.sa_handler);
233 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
234 regs->sp = ptr_to_compat_reg(frame);
235 regs->lr = restorer;
236 regs->regs[0] = (unsigned long) sig;
237 regs->regs[1] = ptr_to_compat_reg(&frame->info);
238 regs->regs[2] = ptr_to_compat_reg(&frame->uc);
239 regs->flags |= PT_FLAGS_CALLER_SAVES;
240 return 0;
241
242 err:
243 trace_unhandled_signal("bad sigreturn frame", regs,
244 (unsigned long)frame, SIGSEGV);
245 return -EFAULT;
246 }
247