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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) | |
3 | * Licensed under the GPL | |
4 | */ | |
5 | ||
6 | #include <stdlib.h> | |
7 | #include <unistd.h> | |
8 | #include <errno.h> | |
9 | #include <signal.h> | |
10 | #include <setjmp.h> | |
11 | #include <sched.h> | |
12 | #include <sys/wait.h> | |
13 | #include <sys/mman.h> | |
14 | #include <sys/user.h> | |
15 | #include <asm/unistd.h> | |
16 | #include "user.h" | |
17 | #include "ptrace_user.h" | |
18 | #include "time_user.h" | |
19 | #include "sysdep/ptrace.h" | |
20 | #include "user_util.h" | |
21 | #include "kern_util.h" | |
22 | #include "skas.h" | |
23 | #include "sysdep/sigcontext.h" | |
24 | #include "os.h" | |
25 | #include "proc_mm.h" | |
26 | #include "skas_ptrace.h" | |
27 | #include "chan_user.h" | |
28 | #include "signal_user.h" | |
29 | #include "registers.h" | |
30 | ||
31 | int is_skas_winch(int pid, int fd, void *data) | |
32 | { | |
33 | if(pid != os_getpid()) | |
34 | return(0); | |
35 | ||
36 | register_winch_irq(-1, fd, -1, data); | |
37 | return(1); | |
38 | } | |
39 | ||
40 | static void handle_segv(int pid) | |
41 | { | |
42 | struct ptrace_faultinfo fault; | |
43 | int err; | |
44 | ||
45 | err = ptrace(PTRACE_FAULTINFO, pid, 0, &fault); | |
46 | if(err) | |
47 | panic("handle_segv - PTRACE_FAULTINFO failed, errno = %d\n", | |
48 | errno); | |
49 | ||
50 | segv(fault.addr, 0, FAULT_WRITE(fault.is_write), 1, NULL); | |
51 | } | |
52 | ||
53 | /*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ | |
54 | static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) | |
55 | { | |
56 | int err, status; | |
57 | ||
58 | /* Mark this as a syscall */ | |
59 | UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs); | |
60 | ||
61 | if (!local_using_sysemu) | |
62 | { | |
63 | err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); | |
64 | if(err < 0) | |
65 | panic("handle_trap - nullifying syscall failed errno = %d\n", | |
66 | errno); | |
67 | ||
68 | err = ptrace(PTRACE_SYSCALL, pid, 0, 0); | |
69 | if(err < 0) | |
70 | panic("handle_trap - continuing to end of syscall failed, " | |
71 | "errno = %d\n", errno); | |
72 | ||
73 | CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); | |
74 | if((err < 0) || !WIFSTOPPED(status) || | |
75 | (WSTOPSIG(status) != SIGTRAP + 0x80)) | |
76 | panic("handle_trap - failed to wait at end of syscall, " | |
77 | "errno = %d, status = %d\n", errno, status); | |
78 | } | |
79 | ||
80 | handle_syscall(regs); | |
81 | } | |
82 | ||
83 | static int userspace_tramp(void *arg) | |
84 | { | |
85 | init_new_thread_signals(0); | |
86 | enable_timer(); | |
87 | ptrace(PTRACE_TRACEME, 0, 0, 0); | |
88 | os_stop_process(os_getpid()); | |
89 | return(0); | |
90 | } | |
91 | ||
92 | /* Each element set once, and only accessed by a single processor anyway */ | |
93 | #undef NR_CPUS | |
94 | #define NR_CPUS 1 | |
95 | int userspace_pid[NR_CPUS]; | |
96 | ||
97 | void start_userspace(int cpu) | |
98 | { | |
99 | void *stack; | |
100 | unsigned long sp; | |
101 | int pid, status, n; | |
102 | ||
103 | stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, | |
104 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
105 | if(stack == MAP_FAILED) | |
106 | panic("start_userspace : mmap failed, errno = %d", errno); | |
107 | sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *); | |
108 | ||
109 | pid = clone(userspace_tramp, (void *) sp, | |
110 | CLONE_FILES | CLONE_VM | SIGCHLD, NULL); | |
111 | if(pid < 0) | |
112 | panic("start_userspace : clone failed, errno = %d", errno); | |
113 | ||
114 | do { | |
115 | CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED)); | |
116 | if(n < 0) | |
117 | panic("start_userspace : wait failed, errno = %d", | |
118 | errno); | |
119 | } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM)); | |
120 | ||
121 | if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP)) | |
122 | panic("start_userspace : expected SIGSTOP, got status = %d", | |
123 | status); | |
124 | ||
125 | if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0) | |
126 | panic("start_userspace : PTRACE_SETOPTIONS failed, errno=%d\n", | |
127 | errno); | |
128 | ||
129 | if(munmap(stack, PAGE_SIZE) < 0) | |
130 | panic("start_userspace : munmap failed, errno = %d\n", errno); | |
131 | ||
132 | userspace_pid[cpu] = pid; | |
133 | } | |
134 | ||
135 | void userspace(union uml_pt_regs *regs) | |
136 | { | |
137 | int err, status, op, pid = userspace_pid[0]; | |
138 | int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ | |
139 | ||
140 | while(1){ | |
141 | restore_registers(pid, regs); | |
142 | ||
143 | /* Now we set local_using_sysemu to be used for one loop */ | |
144 | local_using_sysemu = get_using_sysemu(); | |
145 | ||
146 | op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); | |
147 | ||
148 | err = ptrace(op, pid, 0, 0); | |
149 | if(err) | |
150 | panic("userspace - could not resume userspace process, " | |
151 | "pid=%d, ptrace operation = %d, errno = %d\n", | |
152 | op, errno); | |
153 | ||
154 | CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED)); | |
155 | if(err < 0) | |
156 | panic("userspace - waitpid failed, errno = %d\n", | |
157 | errno); | |
158 | ||
159 | regs->skas.is_user = 1; | |
160 | save_registers(pid, regs); | |
161 | UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */ | |
162 | ||
163 | if(WIFSTOPPED(status)){ | |
164 | switch(WSTOPSIG(status)){ | |
165 | case SIGSEGV: | |
166 | handle_segv(pid); | |
167 | break; | |
168 | case SIGTRAP + 0x80: | |
169 | handle_trap(pid, regs, local_using_sysemu); | |
170 | break; | |
171 | case SIGTRAP: | |
172 | relay_signal(SIGTRAP, regs); | |
173 | break; | |
174 | case SIGIO: | |
175 | case SIGVTALRM: | |
176 | case SIGILL: | |
177 | case SIGBUS: | |
178 | case SIGFPE: | |
179 | case SIGWINCH: | |
180 | user_signal(WSTOPSIG(status), regs); | |
181 | break; | |
182 | default: | |
183 | printk("userspace - child stopped with signal " | |
184 | "%d\n", WSTOPSIG(status)); | |
185 | } | |
186 | interrupt_end(); | |
187 | ||
188 | /* Avoid -ERESTARTSYS handling in host */ | |
189 | PT_SYSCALL_NR(regs->skas.regs) = -1; | |
190 | } | |
191 | } | |
192 | } | |
193 | ||
194 | void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, | |
195 | void (*handler)(int)) | |
196 | { | |
197 | unsigned long flags; | |
198 | sigjmp_buf switch_buf, fork_buf; | |
199 | ||
200 | *switch_buf_ptr = &switch_buf; | |
201 | *fork_buf_ptr = &fork_buf; | |
202 | ||
203 | /* Somewhat subtle - siglongjmp restores the signal mask before doing | |
204 | * the longjmp. This means that when jumping from one stack to another | |
205 | * when the target stack has interrupts enabled, an interrupt may occur | |
206 | * on the source stack. This is bad when starting up a process because | |
207 | * it's not supposed to get timer ticks until it has been scheduled. | |
208 | * So, we disable interrupts around the sigsetjmp to ensure that | |
209 | * they can't happen until we get back here where they are safe. | |
210 | */ | |
211 | flags = get_signals(); | |
212 | block_signals(); | |
213 | if(sigsetjmp(fork_buf, 1) == 0) | |
214 | new_thread_proc(stack, handler); | |
215 | ||
216 | remove_sigstack(); | |
217 | ||
218 | set_signals(flags); | |
219 | } | |
220 | ||
221 | void thread_wait(void *sw, void *fb) | |
222 | { | |
223 | sigjmp_buf buf, **switch_buf = sw, *fork_buf; | |
224 | ||
225 | *switch_buf = &buf; | |
226 | fork_buf = fb; | |
227 | if(sigsetjmp(buf, 1) == 0) | |
228 | siglongjmp(*fork_buf, 1); | |
229 | } | |
230 | ||
231 | void switch_threads(void *me, void *next) | |
232 | { | |
233 | sigjmp_buf my_buf, **me_ptr = me, *next_buf = next; | |
234 | ||
235 | *me_ptr = &my_buf; | |
236 | if(sigsetjmp(my_buf, 1) == 0) | |
237 | siglongjmp(*next_buf, 1); | |
238 | } | |
239 | ||
240 | static sigjmp_buf initial_jmpbuf; | |
241 | ||
242 | /* XXX Make these percpu */ | |
243 | static void (*cb_proc)(void *arg); | |
244 | static void *cb_arg; | |
245 | static sigjmp_buf *cb_back; | |
246 | ||
247 | int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr) | |
248 | { | |
249 | sigjmp_buf **switch_buf = switch_buf_ptr; | |
250 | int n; | |
251 | ||
252 | *fork_buf_ptr = &initial_jmpbuf; | |
253 | n = sigsetjmp(initial_jmpbuf, 1); | |
254 | if(n == 0) | |
255 | new_thread_proc((void *) stack, new_thread_handler); | |
256 | else if(n == 1) | |
257 | remove_sigstack(); | |
258 | else if(n == 2){ | |
259 | (*cb_proc)(cb_arg); | |
260 | siglongjmp(*cb_back, 1); | |
261 | } | |
262 | else if(n == 3){ | |
263 | kmalloc_ok = 0; | |
264 | return(0); | |
265 | } | |
266 | else if(n == 4){ | |
267 | kmalloc_ok = 0; | |
268 | return(1); | |
269 | } | |
270 | siglongjmp(**switch_buf, 1); | |
271 | } | |
272 | ||
273 | void remove_sigstack(void) | |
274 | { | |
275 | stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE, | |
276 | .ss_sp = NULL, | |
277 | .ss_size = 0 }); | |
278 | ||
279 | if(sigaltstack(&stack, NULL) != 0) | |
280 | panic("disabling signal stack failed, errno = %d\n", errno); | |
281 | } | |
282 | ||
283 | void initial_thread_cb_skas(void (*proc)(void *), void *arg) | |
284 | { | |
285 | sigjmp_buf here; | |
286 | ||
287 | cb_proc = proc; | |
288 | cb_arg = arg; | |
289 | cb_back = &here; | |
290 | ||
291 | block_signals(); | |
292 | if(sigsetjmp(here, 1) == 0) | |
293 | siglongjmp(initial_jmpbuf, 2); | |
294 | unblock_signals(); | |
295 | ||
296 | cb_proc = NULL; | |
297 | cb_arg = NULL; | |
298 | cb_back = NULL; | |
299 | } | |
300 | ||
301 | void halt_skas(void) | |
302 | { | |
303 | block_signals(); | |
304 | siglongjmp(initial_jmpbuf, 3); | |
305 | } | |
306 | ||
307 | void reboot_skas(void) | |
308 | { | |
309 | block_signals(); | |
310 | siglongjmp(initial_jmpbuf, 4); | |
311 | } | |
312 | ||
313 | void switch_mm_skas(int mm_fd) | |
314 | { | |
315 | int err; | |
316 | ||
317 | #warning need cpu pid in switch_mm_skas | |
318 | err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0, mm_fd); | |
319 | if(err) | |
320 | panic("switch_mm_skas - PTRACE_SWITCH_MM failed, errno = %d\n", | |
321 | errno); | |
322 | } | |
323 | ||
324 | void kill_off_processes_skas(void) | |
325 | { | |
326 | #warning need to loop over userspace_pids in kill_off_processes_skas | |
327 | os_kill_ptraced_process(userspace_pid[0], 1); | |
328 | } | |
329 | ||
330 | /* | |
331 | * Overrides for Emacs so that we follow Linus's tabbing style. | |
332 | * Emacs will notice this stuff at the end of the file and automatically | |
333 | * adjust the settings for this buffer only. This must remain at the end | |
334 | * of the file. | |
335 | * --------------------------------------------------------------------------- | |
336 | * Local variables: | |
337 | * c-file-style: "linux" | |
338 | * End: | |
339 | */ |