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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
262d96b0 JH |
2 | /* |
3 | * Copyright (C) 1991,1992 Linus Torvalds | |
4 | * Copyright (C) 2005-2012 Imagination Technologies Ltd. | |
5 | * | |
6 | * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | */ | |
9 | ||
10 | #include <linux/sched.h> | |
68db0cf1 | 11 | #include <linux/sched/task_stack.h> |
262d96b0 JH |
12 | #include <linux/mm.h> |
13 | #include <linux/smp.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/signal.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/wait.h> | |
18 | #include <linux/ptrace.h> | |
19 | #include <linux/unistd.h> | |
20 | #include <linux/stddef.h> | |
21 | #include <linux/personality.h> | |
22 | #include <linux/uaccess.h> | |
23 | #include <linux/tracehook.h> | |
24 | ||
25 | #include <asm/ucontext.h> | |
26 | #include <asm/cacheflush.h> | |
27 | #include <asm/switch.h> | |
28 | #include <asm/syscall.h> | |
29 | #include <asm/syscalls.h> | |
30 | ||
31 | #define REG_FLAGS ctx.SaveMask | |
32 | #define REG_RETVAL ctx.DX[0].U0 | |
33 | #define REG_SYSCALL ctx.DX[0].U1 | |
34 | #define REG_SP ctx.AX[0].U0 | |
35 | #define REG_ARG1 ctx.DX[3].U1 | |
36 | #define REG_ARG2 ctx.DX[3].U0 | |
37 | #define REG_ARG3 ctx.DX[2].U1 | |
38 | #define REG_PC ctx.CurrPC | |
39 | #define REG_RTP ctx.DX[4].U1 | |
40 | ||
41 | struct rt_sigframe { | |
42 | struct siginfo info; | |
43 | struct ucontext uc; | |
44 | unsigned long retcode[2]; | |
45 | }; | |
46 | ||
47 | static int restore_sigcontext(struct pt_regs *regs, | |
48 | struct sigcontext __user *sc) | |
49 | { | |
50 | int err; | |
51 | ||
52 | /* Always make any pending restarted system calls return -EINTR */ | |
f56141e3 | 53 | current->restart_block.fn = do_no_restart_syscall; |
262d96b0 JH |
54 | |
55 | err = metag_gp_regs_copyin(regs, 0, sizeof(struct user_gp_regs), NULL, | |
56 | &sc->regs); | |
57 | if (!err) | |
58 | err = metag_cb_regs_copyin(regs, 0, | |
59 | sizeof(struct user_cb_regs), NULL, | |
60 | &sc->cb); | |
61 | if (!err) | |
62 | err = metag_rp_state_copyin(regs, 0, | |
63 | sizeof(struct user_rp_state), NULL, | |
64 | &sc->rp); | |
65 | ||
66 | /* This is a user-mode context. */ | |
67 | regs->REG_FLAGS |= TBICTX_PRIV_BIT; | |
68 | ||
69 | return err; | |
70 | } | |
71 | ||
72 | long sys_rt_sigreturn(void) | |
73 | { | |
74 | /* NOTE - Meta stack goes UPWARDS - so we wind the stack back */ | |
75 | struct pt_regs *regs = current_pt_regs(); | |
76 | struct rt_sigframe __user *frame; | |
77 | sigset_t set; | |
78 | ||
79 | frame = (__force struct rt_sigframe __user *)(regs->REG_SP - | |
80 | sizeof(*frame)); | |
81 | ||
82 | if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) | |
83 | goto badframe; | |
84 | ||
85 | if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) | |
86 | goto badframe; | |
87 | ||
88 | set_current_blocked(&set); | |
89 | ||
90 | if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) | |
91 | goto badframe; | |
92 | ||
93 | if (restore_altstack(&frame->uc.uc_stack)) | |
94 | goto badframe; | |
95 | ||
96 | return regs->REG_RETVAL; | |
97 | ||
98 | badframe: | |
99 | force_sig(SIGSEGV, current); | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, | |
105 | unsigned long mask) | |
106 | { | |
107 | int err; | |
108 | ||
109 | err = metag_gp_regs_copyout(regs, 0, sizeof(struct user_gp_regs), NULL, | |
110 | &sc->regs); | |
111 | ||
112 | if (!err) | |
113 | err = metag_cb_regs_copyout(regs, 0, | |
114 | sizeof(struct user_cb_regs), NULL, | |
115 | &sc->cb); | |
116 | if (!err) | |
117 | err = metag_rp_state_copyout(regs, 0, | |
118 | sizeof(struct user_rp_state), NULL, | |
119 | &sc->rp); | |
120 | ||
121 | /* OK, clear that cbuf flag in the old context, or our stored | |
122 | * catch buffer will be restored when we go to call the signal | |
123 | * handler. Also clear out the CBRP RA/RD pipe bit incase | |
124 | * that is pending as well! | |
125 | * Note that as we have already stored this context, these | |
126 | * flags will get restored on sigreturn to their original | |
127 | * state. | |
128 | */ | |
129 | regs->REG_FLAGS &= ~(TBICTX_XCBF_BIT | TBICTX_CBUF_BIT | | |
130 | TBICTX_CBRP_BIT); | |
131 | ||
132 | /* Clear out the LSM_STEP bits in case we are in the middle of | |
133 | * and MSET/MGET. | |
134 | */ | |
135 | regs->ctx.Flags &= ~TXSTATUS_LSM_STEP_BITS; | |
136 | ||
137 | err |= __put_user(mask, &sc->oldmask); | |
138 | ||
139 | return err; | |
140 | } | |
141 | ||
142 | /* | |
143 | * Determine which stack to use.. | |
144 | */ | |
d83961b7 | 145 | static void __user *get_sigframe(struct ksignal *ksig, unsigned long sp) |
262d96b0 | 146 | { |
d83961b7 | 147 | sp = sigsp(sp, ksig); |
262d96b0 JH |
148 | sp = (sp + 7) & ~7; /* 8byte align stack */ |
149 | ||
150 | return (void __user *)sp; | |
151 | } | |
152 | ||
d3c7e511 RW |
153 | static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, |
154 | struct pt_regs *regs) | |
262d96b0 JH |
155 | { |
156 | struct rt_sigframe __user *frame; | |
d3c7e511 | 157 | int err; |
262d96b0 JH |
158 | unsigned long code; |
159 | ||
d83961b7 | 160 | frame = get_sigframe(ksig, regs->REG_SP); |
262d96b0 | 161 | if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) |
d3c7e511 | 162 | return -EFAULT; |
262d96b0 | 163 | |
d3c7e511 | 164 | err = copy_siginfo_to_user(&frame->info, &ksig->info); |
262d96b0 JH |
165 | |
166 | /* Create the ucontext. */ | |
167 | err |= __put_user(0, &frame->uc.uc_flags); | |
168 | err |= __put_user(0, (unsigned long __user *)&frame->uc.uc_link); | |
169 | err |= __save_altstack(&frame->uc.uc_stack, regs->REG_SP); | |
170 | err |= setup_sigcontext(&frame->uc.uc_mcontext, | |
171 | regs, set->sig[0]); | |
172 | err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); | |
173 | ||
174 | if (err) | |
d3c7e511 | 175 | return -EFAULT; |
262d96b0 JH |
176 | |
177 | /* Set up to return from userspace. */ | |
178 | ||
179 | /* MOV D1Re0 (D1.0), #__NR_rt_sigreturn */ | |
180 | code = 0x03000004 | (__NR_rt_sigreturn << 3); | |
181 | err |= __put_user(code, (unsigned long __user *)(&frame->retcode[0])); | |
182 | ||
183 | /* SWITCH #__METAG_SW_SYS */ | |
184 | code = __METAG_SW_ENCODING(SYS); | |
185 | err |= __put_user(code, (unsigned long __user *)(&frame->retcode[1])); | |
186 | ||
187 | if (err) | |
d3c7e511 | 188 | return -EFAULT; |
262d96b0 JH |
189 | |
190 | /* Set up registers for signal handler */ | |
191 | regs->REG_RTP = (unsigned long) frame->retcode; | |
192 | regs->REG_SP = (unsigned long) frame + sizeof(*frame); | |
d3c7e511 | 193 | regs->REG_ARG1 = ksig->sig; |
262d96b0 JH |
194 | regs->REG_ARG2 = (unsigned long) &frame->info; |
195 | regs->REG_ARG3 = (unsigned long) &frame->uc; | |
d3c7e511 | 196 | regs->REG_PC = (unsigned long) ksig->ka.sa.sa_handler; |
262d96b0 JH |
197 | |
198 | pr_debug("SIG deliver (%s:%d): sp=%p pc=%08x pr=%08x\n", | |
199 | current->comm, current->pid, frame, regs->REG_PC, | |
200 | regs->REG_RTP); | |
201 | ||
202 | /* Now pass size of 'new code' into sigtramp so we can do a more | |
203 | * effective cache flush - directed rather than 'full flush'. | |
204 | */ | |
205 | flush_cache_sigtramp(regs->REG_RTP, sizeof(frame->retcode)); | |
d3c7e511 | 206 | |
262d96b0 JH |
207 | return 0; |
208 | } | |
209 | ||
d3c7e511 | 210 | static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) |
262d96b0 JH |
211 | { |
212 | sigset_t *oldset = sigmask_to_save(); | |
d3c7e511 | 213 | int ret; |
262d96b0 JH |
214 | |
215 | /* Set up the stack frame */ | |
d3c7e511 | 216 | ret = setup_rt_frame(ksig, oldset, regs); |
262d96b0 | 217 | |
d3c7e511 | 218 | signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); |
262d96b0 JH |
219 | } |
220 | ||
221 | /* | |
222 | * Notes for Meta. | |
223 | * We have moved from the old 2.4.9 SH way of using syscall_nr (in the stored | |
224 | * context) to passing in the syscall flag on the stack. | |
225 | * This is because having syscall_nr in our context does not fit with TBX, and | |
226 | * corrupted the stack. | |
227 | */ | |
228 | static int do_signal(struct pt_regs *regs, int syscall) | |
229 | { | |
230 | unsigned int retval = 0, continue_addr = 0, restart_addr = 0; | |
262d96b0 | 231 | int restart = 0; |
d3c7e511 | 232 | struct ksignal ksig; |
262d96b0 JH |
233 | |
234 | /* | |
235 | * By the end of rt_sigreturn the context describes the point that the | |
236 | * signal was taken (which may happen to be just before a syscall if | |
237 | * it's already been restarted). This should *never* be mistaken for a | |
238 | * system call in need of restarting. | |
239 | */ | |
240 | if (syscall == __NR_rt_sigreturn) | |
241 | syscall = -1; | |
242 | ||
243 | /* Did we come from a system call? */ | |
244 | if (syscall >= 0) { | |
245 | continue_addr = regs->REG_PC; | |
246 | restart_addr = continue_addr - 4; | |
247 | retval = regs->REG_RETVAL; | |
248 | ||
249 | /* | |
250 | * Prepare for system call restart. We do this here so that a | |
251 | * debugger will see the already changed PC. | |
252 | */ | |
253 | switch (retval) { | |
254 | case -ERESTART_RESTARTBLOCK: | |
255 | restart = -2; | |
256 | case -ERESTARTNOHAND: | |
257 | case -ERESTARTSYS: | |
258 | case -ERESTARTNOINTR: | |
259 | ++restart; | |
260 | regs->REG_PC = restart_addr; | |
261 | break; | |
262 | } | |
263 | } | |
264 | ||
265 | /* | |
266 | * Get the signal to deliver. When running under ptrace, at this point | |
267 | * the debugger may change all our registers ... | |
268 | */ | |
d3c7e511 RW |
269 | get_signal(&ksig); |
270 | ||
262d96b0 JH |
271 | /* |
272 | * Depending on the signal settings we may need to revert the decision | |
273 | * to restart the system call. But skip this if a debugger has chosen to | |
274 | * restart at a different PC. | |
275 | */ | |
276 | if (regs->REG_PC != restart_addr) | |
277 | restart = 0; | |
d3c7e511 | 278 | if (ksig.sig > 0) { |
262d96b0 JH |
279 | if (unlikely(restart)) { |
280 | if (retval == -ERESTARTNOHAND | |
281 | || retval == -ERESTART_RESTARTBLOCK | |
282 | || (retval == -ERESTARTSYS | |
d3c7e511 | 283 | && !(ksig.ka.sa.sa_flags & SA_RESTART))) { |
262d96b0 JH |
284 | regs->REG_RETVAL = -EINTR; |
285 | regs->REG_PC = continue_addr; | |
286 | } | |
287 | } | |
288 | ||
289 | /* Whee! Actually deliver the signal. */ | |
d3c7e511 | 290 | handle_signal(&ksig, regs); |
262d96b0 JH |
291 | return 0; |
292 | } | |
293 | ||
294 | /* Handlerless -ERESTART_RESTARTBLOCK re-enters via restart_syscall */ | |
295 | if (unlikely(restart < 0)) | |
296 | regs->REG_SYSCALL = __NR_restart_syscall; | |
297 | ||
298 | /* | |
299 | * If there's no signal to deliver, we just put the saved sigmask back. | |
300 | */ | |
301 | restore_saved_sigmask(); | |
302 | ||
303 | return restart; | |
304 | } | |
305 | ||
306 | int do_work_pending(struct pt_regs *regs, unsigned int thread_flags, | |
307 | int syscall) | |
308 | { | |
309 | do { | |
310 | if (likely(thread_flags & _TIF_NEED_RESCHED)) { | |
311 | schedule(); | |
312 | } else { | |
313 | if (unlikely(!user_mode(regs))) | |
314 | return 0; | |
315 | local_irq_enable(); | |
316 | if (thread_flags & _TIF_SIGPENDING) { | |
317 | int restart = do_signal(regs, syscall); | |
318 | if (unlikely(restart)) { | |
319 | /* | |
320 | * Restart without handlers. | |
321 | * Deal with it without leaving | |
322 | * the kernel space. | |
323 | */ | |
324 | return restart; | |
325 | } | |
326 | syscall = -1; | |
327 | } else { | |
328 | clear_thread_flag(TIF_NOTIFY_RESUME); | |
329 | tracehook_notify_resume(regs); | |
330 | } | |
331 | } | |
332 | local_irq_disable(); | |
333 | thread_flags = current_thread_info()->flags; | |
334 | } while (thread_flags & _TIF_WORK_MASK); | |
335 | return 0; | |
336 | } |