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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
38struct 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
46struct 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
52int 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(ptr_to_compat(from->si_ptr), &to->si_ptr);
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(ptr_to_compat(from->si_ptr),
97 &to->si_ptr);
98 break;
99 /* This is not generated by the kernel as of now. */
100 case __SI_RT >> 16:
101 case __SI_MESGQ >> 16:
102 err |= __put_user(from->si_uid, &to->si_uid);
103 err |= __put_user(from->si_int, &to->si_int);
104 break;
105 }
106 }
107 return err;
108}
109
110int copy_siginfo_from_user32(siginfo_t *to, struct compat_siginfo __user *from)
111{
112 int err;
113 u32 ptr32;
114
115 if (!access_ok(VERIFY_READ, from, sizeof(struct compat_siginfo)))
116 return -EFAULT;
117
118 err = __get_user(to->si_signo, &from->si_signo);
119 err |= __get_user(to->si_errno, &from->si_errno);
120 err |= __get_user(to->si_code, &from->si_code);
121
122 err |= __get_user(to->si_pid, &from->si_pid);
123 err |= __get_user(to->si_uid, &from->si_uid);
124 err |= __get_user(ptr32, &from->si_ptr);
125 to->si_ptr = compat_ptr(ptr32);
126
127 return err;
128}
129
130/* The assembly shim for this function arranges to ignore the return value. */
131long compat_sys_rt_sigreturn(void)
132{
133 struct pt_regs *regs = current_pt_regs();
134 struct compat_rt_sigframe __user *frame =
135 (struct compat_rt_sigframe __user *) compat_ptr(regs->sp);
136 sigset_t set;
137
138 if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
139 goto badframe;
140 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
141 goto badframe;
142
143 set_current_blocked(&set);
144
145 if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
146 goto badframe;
147
148 if (compat_restore_altstack(&frame->uc.uc_stack))
149 goto badframe;
150
151 return 0;
152
153badframe:
154 signal_fault("bad sigreturn frame", regs, frame, 0);
155 return 0;
156}
157
158/*
159 * Determine which stack to use..
160 */
161static inline void __user *compat_get_sigframe(struct k_sigaction *ka,
162 struct pt_regs *regs,
163 size_t frame_size)
164{
165 unsigned long sp;
166
167 /* Default to using normal stack */
168 sp = (unsigned long)compat_ptr(regs->sp);
169
170 /*
171 * If we are on the alternate signal stack and would overflow
172 * it, don't. Return an always-bogus address instead so we
173 * will die with SIGSEGV.
174 */
175 if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
176 return (void __user __force *)-1UL;
177
178 /* This is the X/Open sanctioned signal stack switching. */
179 if (ka->sa.sa_flags & SA_ONSTACK) {
180 if (sas_ss_flags(sp) == 0)
181 sp = current->sas_ss_sp + current->sas_ss_size;
182 }
183
184 sp -= frame_size;
185 /*
186 * Align the stack pointer according to the TILE ABI,
187 * i.e. so that on function entry (sp & 15) == 0.
188 */
189 sp &= -16UL;
190 return (void __user *) sp;
191}
192
193int compat_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
194 sigset_t *set, struct pt_regs *regs)
195{
196 unsigned long restorer;
197 struct compat_rt_sigframe __user *frame;
198 int err = 0;
199 int usig;
200
201 frame = compat_get_sigframe(ka, regs, sizeof(*frame));
202
203 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
204 goto give_sigsegv;
205
206 usig = current_thread_info()->exec_domain
207 && current_thread_info()->exec_domain->signal_invmap
208 && sig < 32
209 ? current_thread_info()->exec_domain->signal_invmap[sig]
210 : sig;
211
212 /* Always write at least the signal number for the stack backtracer. */
213 if (ka->sa.sa_flags & SA_SIGINFO) {
214 /* At sigreturn time, restore the callee-save registers too. */
215 err |= copy_siginfo_to_user32(&frame->info, info);
216 regs->flags |= PT_FLAGS_RESTORE_REGS;
217 } else {
218 err |= __put_user(info->si_signo, &frame->info.si_signo);
219 }
220
221 /* Create the ucontext. */
222 err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
223 err |= __put_user(0, &frame->uc.uc_flags);
224 err |= __put_user(0, &frame->uc.uc_link);
225 err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
226 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
227 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
228 if (err)
229 goto give_sigsegv;
230
231 restorer = VDSO_SYM(&__vdso_rt_sigreturn);
232 if (ka->sa.sa_flags & SA_RESTORER)
233 restorer = ptr_to_compat_reg(ka->sa.sa_restorer);
234
235 /*
236 * Set up registers for signal handler.
237 * Registers that we don't modify keep the value they had from
238 * user-space at the time we took the signal.
239 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
240 * since some things rely on this (e.g. glibc's debug/segfault.c).
241 */
242 regs->pc = ptr_to_compat_reg(ka->sa.sa_handler);
243 regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
244 regs->sp = ptr_to_compat_reg(frame);
245 regs->lr = restorer;
246 regs->regs[0] = (unsigned long) usig;
247 regs->regs[1] = ptr_to_compat_reg(&frame->info);
248 regs->regs[2] = ptr_to_compat_reg(&frame->uc);
249 regs->flags |= PT_FLAGS_CALLER_SAVES;
250 return 0;
251
252give_sigsegv:
253 signal_fault("bad setup frame", regs, frame, sig);
254 return -EFAULT;
255}