1 /*
2 * Copyright (C) 2003 PathScale, Inc.
3 * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
5 */
6
7 #include <linux/personality.h>
8 #include <linux/ptrace.h>
9 #include <asm/unistd.h>
10 #include <asm/uaccess.h>
11 #include <asm/ucontext.h>
12 #include "frame_kern.h"
13 #include "skas.h"
14
15 void copy_sc(struct uml_pt_regs *regs, void *from)
16 {
17 struct sigcontext *sc = from;
18
19 #define GETREG(regs, regno, sc, regname) \
20 (regs)->gp[(regno) / sizeof(unsigned long)] = (sc)->regname
21
22 GETREG(regs, R8, sc, r8);
23 GETREG(regs, R9, sc, r9);
24 GETREG(regs, R10, sc, r10);
25 GETREG(regs, R11, sc, r11);
26 GETREG(regs, R12, sc, r12);
27 GETREG(regs, R13, sc, r13);
28 GETREG(regs, R14, sc, r14);
29 GETREG(regs, R15, sc, r15);
30 GETREG(regs, RDI, sc, di);
31 GETREG(regs, RSI, sc, si);
32 GETREG(regs, RBP, sc, bp);
33 GETREG(regs, RBX, sc, bx);
34 GETREG(regs, RDX, sc, dx);
35 GETREG(regs, RAX, sc, ax);
36 GETREG(regs, RCX, sc, cx);
37 GETREG(regs, RSP, sc, sp);
38 GETREG(regs, RIP, sc, ip);
39 GETREG(regs, EFLAGS, sc, flags);
40 GETREG(regs, CS, sc, cs);
41
42 #undef GETREG
43 }
44
45 static int copy_sc_from_user(struct pt_regs *regs,
46 struct sigcontext __user *from,
47 struct _fpstate __user *fpp)
48 {
49 struct user_i387_struct fp;
50 int err = 0;
51
52 #define GETREG(regs, regno, sc, regname) \
53 __get_user((regs)->regs.gp[(regno) / sizeof(unsigned long)], \
54 &(sc)->regname)
55
56 err |= GETREG(regs, R8, from, r8);
57 err |= GETREG(regs, R9, from, r9);
58 err |= GETREG(regs, R10, from, r10);
59 err |= GETREG(regs, R11, from, r11);
60 err |= GETREG(regs, R12, from, r12);
61 err |= GETREG(regs, R13, from, r13);
62 err |= GETREG(regs, R14, from, r14);
63 err |= GETREG(regs, R15, from, r15);
64 err |= GETREG(regs, RDI, from, di);
65 err |= GETREG(regs, RSI, from, si);
66 err |= GETREG(regs, RBP, from, bp);
67 err |= GETREG(regs, RBX, from, bx);
68 err |= GETREG(regs, RDX, from, dx);
69 err |= GETREG(regs, RAX, from, ax);
70 err |= GETREG(regs, RCX, from, cx);
71 err |= GETREG(regs, RSP, from, sp);
72 err |= GETREG(regs, RIP, from, ip);
73 err |= GETREG(regs, EFLAGS, from, flags);
74 err |= GETREG(regs, CS, from, cs);
75 if (err)
76 return 1;
77
78 #undef GETREG
79
80 err = copy_from_user(&fp, fpp, sizeof(struct user_i387_struct));
81 if (err)
82 return 1;
83
84 err = restore_fp_registers(userspace_pid[current_thread_info()->cpu],
85 (unsigned long *) &fp);
86 if (err < 0) {
87 printk(KERN_ERR "copy_sc_from_user - "
88 "restore_fp_registers failed, errno = %d\n",
89 -err);
90 return 1;
91 }
92
93 return 0;
94 }
95
96 static int copy_sc_to_user(struct sigcontext __user *to,
97 struct _fpstate __user *to_fp, struct pt_regs *regs,
98 unsigned long mask, unsigned long sp)
99 {
100 struct faultinfo * fi = ¤t->thread.arch.faultinfo;
101 struct user_i387_struct fp;
102 int err = 0;
103
104 err |= __put_user(0, &to->gs);
105 err |= __put_user(0, &to->fs);
106
107 #define PUTREG(regs, regno, sc, regname) \
108 __put_user((regs)->regs.gp[(regno) / sizeof(unsigned long)], \
109 &(sc)->regname)
110
111 err |= PUTREG(regs, RDI, to, di);
112 err |= PUTREG(regs, RSI, to, si);
113 err |= PUTREG(regs, RBP, to, bp);
114 /*
115 * Must use original RSP, which is passed in, rather than what's in
116 * the pt_regs, because that's already been updated to point at the
117 * signal frame.
118 */
119 err |= __put_user(sp, &to->sp);
120 err |= PUTREG(regs, RBX, to, bx);
121 err |= PUTREG(regs, RDX, to, dx);
122 err |= PUTREG(regs, RCX, to, cx);
123 err |= PUTREG(regs, RAX, to, ax);
124 err |= PUTREG(regs, R8, to, r8);
125 err |= PUTREG(regs, R9, to, r9);
126 err |= PUTREG(regs, R10, to, r10);
127 err |= PUTREG(regs, R11, to, r11);
128 err |= PUTREG(regs, R12, to, r12);
129 err |= PUTREG(regs, R13, to, r13);
130 err |= PUTREG(regs, R14, to, r14);
131 err |= PUTREG(regs, R15, to, r15);
132 err |= PUTREG(regs, CS, to, cs); /* XXX x86_64 doesn't do this */
133
134 err |= __put_user(fi->cr2, &to->cr2);
135 err |= __put_user(fi->error_code, &to->err);
136 err |= __put_user(fi->trap_no, &to->trapno);
137
138 err |= PUTREG(regs, RIP, to, ip);
139 err |= PUTREG(regs, EFLAGS, to, flags);
140 #undef PUTREG
141
142 err |= __put_user(mask, &to->oldmask);
143 if (err)
144 return 1;
145
146 err = save_fp_registers(userspace_pid[current_thread_info()->cpu],
147 (unsigned long *) &fp);
148 if (err < 0) {
149 printk(KERN_ERR "copy_sc_from_user - restore_fp_registers "
150 "failed, errno = %d\n", -err);
151 return 1;
152 }
153
154 if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
155 return 1;
156
157 return err;
158 }
159
160 struct rt_sigframe
161 {
162 char __user *pretcode;
163 struct ucontext uc;
164 struct siginfo info;
165 struct _fpstate fpstate;
166 };
167
168 #define round_down(m, n) (((m) / (n)) * (n))
169
170 int setup_signal_stack_si(unsigned long stack_top, int sig,
171 struct k_sigaction *ka, struct pt_regs * regs,
172 siginfo_t *info, sigset_t *set)
173 {
174 struct rt_sigframe __user *frame;
175 unsigned long save_sp = PT_REGS_RSP(regs);
176 int err = 0;
177 struct task_struct *me = current;
178
179 frame = (struct rt_sigframe __user *)
180 round_down(stack_top - sizeof(struct rt_sigframe), 16);
181 /* Subtract 128 for a red zone and 8 for proper alignment */
182 frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
183
184 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
185 goto out;
186
187 if (ka->sa.sa_flags & SA_SIGINFO) {
188 err |= copy_siginfo_to_user(&frame->info, info);
189 if (err)
190 goto out;
191 }
192
193 /*
194 * Update SP now because the page fault handler refuses to extend
195 * the stack if the faulting address is too far below the current
196 * SP, which frame now certainly is. If there's an error, the original
197 * value is restored on the way out.
198 * When writing the sigcontext to the stack, we have to write the
199 * original value, so that's passed to copy_sc_to_user, which does
200 * the right thing with it.
201 */
202 PT_REGS_RSP(regs) = (unsigned long) frame;
203
204 /* Create the ucontext. */
205 err |= __put_user(0, &frame->uc.uc_flags);
206 err |= __put_user(0, &frame->uc.uc_link);
207 err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
208 err |= __put_user(sas_ss_flags(save_sp),
209 &frame->uc.uc_stack.ss_flags);
210 err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
211 err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
212 set->sig[0], save_sp);
213 err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);
214 if (sizeof(*set) == 16) {
215 __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
216 __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
217 }
218 else
219 err |= __copy_to_user(&frame->uc.uc_sigmask, set,
220 sizeof(*set));
221
222 /*
223 * Set up to return from userspace. If provided, use a stub
224 * already in userspace.
225 */
226 /* x86-64 should always use SA_RESTORER. */
227 if (ka->sa.sa_flags & SA_RESTORER)
228 err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
229 else
230 /* could use a vstub here */
231 goto restore_sp;
232
233 if (err)
234 goto restore_sp;
235
236 /* Set up registers for signal handler */
237 {
238 struct exec_domain *ed = current_thread_info()->exec_domain;
239 if (unlikely(ed && ed->signal_invmap && sig < 32))
240 sig = ed->signal_invmap[sig];
241 }
242
243 PT_REGS_RDI(regs) = sig;
244 /* In case the signal handler was declared without prototypes */
245 PT_REGS_RAX(regs) = 0;
246
247 /*
248 * This also works for non SA_SIGINFO handlers because they expect the
249 * next argument after the signal number on the stack.
250 */
251 PT_REGS_RSI(regs) = (unsigned long) &frame->info;
252 PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
253 PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
254 out:
255 return err;
256
257 restore_sp:
258 PT_REGS_RSP(regs) = save_sp;
259 return err;
260 }
261
262 long sys_rt_sigreturn(struct pt_regs *regs)
263 {
264 unsigned long sp = PT_REGS_SP(¤t->thread.regs);
265 struct rt_sigframe __user *frame =
266 (struct rt_sigframe __user *)(sp - 8);
267 struct ucontext __user *uc = &frame->uc;
268 sigset_t set;
269
270 if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
271 goto segfault;
272
273 sigdelsetmask(&set, ~_BLOCKABLE);
274
275 spin_lock_irq(¤t->sighand->siglock);
276 current->blocked = set;
277 recalc_sigpending();
278 spin_unlock_irq(¤t->sighand->siglock);
279
280 if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext,
281 &frame->fpstate))
282 goto segfault;
283
284 /* Avoid ERESTART handling */
285 PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
286 return PT_REGS_SYSCALL_RET(¤t->thread.regs);
287
288 segfault:
289 force_sig(SIGSEGV, current);
290 return 0;
291 }
292
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