~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/openrisc/kernel/signal.c

Version: ~ [ linux-6.0-rc6 ] ~ [ linux-5.19.10 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.69 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.144 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.214 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.259 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.294 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.329 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.302 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * OpenRISC signal.c
  3  *
  4  * Linux architectural port borrowing liberally from similar works of
  5  * others.  All original copyrights apply as per the original source
  6  * declaration.
  7  *
  8  * Modifications for the OpenRISC architecture:
  9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 11  *
 12  *      This program is free software; you can redistribute it and/or
 13  *      modify it under the terms of the GNU General Public License
 14  *      as published by the Free Software Foundation; either version
 15  *      2 of the License, or (at your option) any later version.
 16  */
 17 
 18 #include <linux/sched.h>
 19 #include <linux/mm.h>
 20 #include <linux/smp.h>
 21 #include <linux/kernel.h>
 22 #include <linux/signal.h>
 23 #include <linux/errno.h>
 24 #include <linux/wait.h>
 25 #include <linux/ptrace.h>
 26 #include <linux/unistd.h>
 27 #include <linux/stddef.h>
 28 #include <linux/tracehook.h>
 29 
 30 #include <asm/processor.h>
 31 #include <asm/syscall.h>
 32 #include <asm/ucontext.h>
 33 #include <linux/uaccess.h>
 34 
 35 #define DEBUG_SIG 0
 36 
 37 struct rt_sigframe {
 38         struct siginfo info;
 39         struct ucontext uc;
 40         unsigned char retcode[16];      /* trampoline code */
 41 };
 42 
 43 static int restore_sigcontext(struct pt_regs *regs,
 44                               struct sigcontext __user *sc)
 45 {
 46         int err = 0;
 47 
 48         /* Always make any pending restarted system calls return -EINTR */
 49         current->restart_block.fn = do_no_restart_syscall;
 50 
 51         /*
 52          * Restore the regs from &sc->regs.
 53          * (sc is already checked since the sigframe was
 54          *  checked in sys_sigreturn previously)
 55          */
 56         err |= __copy_from_user(regs, sc->regs.gpr, 32 * sizeof(unsigned long));
 57         err |= __copy_from_user(&regs->pc, &sc->regs.pc, sizeof(unsigned long));
 58         err |= __copy_from_user(&regs->sr, &sc->regs.sr, sizeof(unsigned long));
 59 
 60         /* make sure the SM-bit is cleared so user-mode cannot fool us */
 61         regs->sr &= ~SPR_SR_SM;
 62 
 63         regs->orig_gpr11 = -1;  /* Avoid syscall restart checks */
 64 
 65         /* TODO: the other ports use regs->orig_XX to disable syscall checks
 66          * after this completes, but we don't use that mechanism. maybe we can
 67          * use it now ?
 68          */
 69 
 70         return err;
 71 }
 72 
 73 asmlinkage long _sys_rt_sigreturn(struct pt_regs *regs)
 74 {
 75         struct rt_sigframe *frame = (struct rt_sigframe __user *)regs->sp;
 76         sigset_t set;
 77 
 78         /*
 79          * Since we stacked the signal on a dword boundary,
 80          * then frame should be dword aligned here.  If it's
 81          * not, then the user is trying to mess with us.
 82          */
 83         if (((long)frame) & 3)
 84                 goto badframe;
 85 
 86         if (!access_ok(frame, sizeof(*frame)))
 87                 goto badframe;
 88         if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 89                 goto badframe;
 90 
 91         set_current_blocked(&set);
 92 
 93         if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 94                 goto badframe;
 95 
 96         if (restore_altstack(&frame->uc.uc_stack))
 97                 goto badframe;
 98 
 99         return regs->gpr[11];
100 
101 badframe:
102         force_sig(SIGSEGV, current);
103         return 0;
104 }
105 
106 /*
107  * Set up a signal frame.
108  */
109 
110 static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
111 {
112         int err = 0;
113 
114         /* copy the regs */
115         /* There should be no need to save callee-saved registers here...
116          * ...but we save them anyway.  Revisit this
117          */
118         err |= __copy_to_user(sc->regs.gpr, regs, 32 * sizeof(unsigned long));
119         err |= __copy_to_user(&sc->regs.pc, &regs->pc, sizeof(unsigned long));
120         err |= __copy_to_user(&sc->regs.sr, &regs->sr, sizeof(unsigned long));
121 
122         return err;
123 }
124 
125 static inline unsigned long align_sigframe(unsigned long sp)
126 {
127         return sp & ~3UL;
128 }
129 
130 /*
131  * Work out where the signal frame should go.  It's either on the user stack
132  * or the alternate stack.
133  */
134 
135 static inline void __user *get_sigframe(struct ksignal *ksig,
136                                         struct pt_regs *regs, size_t frame_size)
137 {
138         unsigned long sp = regs->sp;
139 
140         /* redzone */
141         sp -= STACK_FRAME_OVERHEAD;
142         sp = sigsp(sp, ksig);
143         sp = align_sigframe(sp - frame_size);
144 
145         return (void __user *)sp;
146 }
147 
148 /* grab and setup a signal frame.
149  *
150  * basically we stack a lot of state info, and arrange for the
151  * user-mode program to return to the kernel using either a
152  * trampoline which performs the syscall sigreturn, or a provided
153  * user-mode trampoline.
154  */
155 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
156                           struct pt_regs *regs)
157 {
158         struct rt_sigframe *frame;
159         unsigned long return_ip;
160         int err = 0;
161 
162         frame = get_sigframe(ksig, regs, sizeof(*frame));
163 
164         if (!access_ok(frame, sizeof(*frame)))
165                 return -EFAULT;
166 
167         /* Create siginfo.  */
168         if (ksig->ka.sa.sa_flags & SA_SIGINFO)
169                 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
170 
171         /* Create the ucontext.  */
172         err |= __put_user(0, &frame->uc.uc_flags);
173         err |= __put_user(NULL, &frame->uc.uc_link);
174         err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
175         err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
176 
177         err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
178 
179         if (err)
180                 return -EFAULT;
181 
182         /* trampoline - the desired return ip is the retcode itself */
183         return_ip = (unsigned long)&frame->retcode;
184         /* This is:
185                 l.ori r11,r0,__NR_sigreturn
186                 l.sys 1
187          */
188         err |= __put_user(0xa960,             (short *)(frame->retcode + 0));
189         err |= __put_user(__NR_rt_sigreturn,  (short *)(frame->retcode + 2));
190         err |= __put_user(0x20000001, (unsigned long *)(frame->retcode + 4));
191         err |= __put_user(0x15000000, (unsigned long *)(frame->retcode + 8));
192 
193         if (err)
194                 return -EFAULT;
195 
196         /* Set up registers for signal handler */
197         regs->pc = (unsigned long)ksig->ka.sa.sa_handler; /* what we enter NOW */
198         regs->gpr[9] = (unsigned long)return_ip;     /* what we enter LATER */
199         regs->gpr[3] = (unsigned long)ksig->sig;           /* arg 1: signo */
200         regs->gpr[4] = (unsigned long)&frame->info;  /* arg 2: (siginfo_t*) */
201         regs->gpr[5] = (unsigned long)&frame->uc;    /* arg 3: ucontext */
202 
203         /* actually move the usp to reflect the stacked frame */
204         regs->sp = (unsigned long)frame;
205 
206         return 0;
207 }
208 
209 static inline void
210 handle_signal(struct ksignal *ksig, struct pt_regs *regs)
211 {
212         int ret;
213 
214         ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
215 
216         signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
217 }
218 
219 /*
220  * Note that 'init' is a special process: it doesn't get signals it doesn't
221  * want to handle. Thus you cannot kill init even with a SIGKILL even by
222  * mistake.
223  *
224  * Also note that the regs structure given here as an argument, is the latest
225  * pushed pt_regs. It may or may not be the same as the first pushed registers
226  * when the initial usermode->kernelmode transition took place. Therefore
227  * we can use user_mode(regs) to see if we came directly from kernel or user
228  * mode below.
229  */
230 
231 int do_signal(struct pt_regs *regs, int syscall)
232 {
233         struct ksignal ksig;
234         unsigned long continue_addr = 0;
235         unsigned long restart_addr = 0;
236         unsigned long retval = 0;
237         int restart = 0;
238 
239         if (syscall) {
240                 continue_addr = regs->pc;
241                 restart_addr = continue_addr - 4;
242                 retval = regs->gpr[11];
243 
244                 /*
245                  * Setup syscall restart here so that a debugger will
246                  * see the already changed PC.
247                  */
248                 switch (retval) {
249                 case -ERESTART_RESTARTBLOCK:
250                         restart = -2;
251                         /* Fall through */
252                 case -ERESTARTNOHAND:
253                 case -ERESTARTSYS:
254                 case -ERESTARTNOINTR:
255                         restart++;
256                         regs->gpr[11] = regs->orig_gpr11;
257                         regs->pc = restart_addr;
258                         break;
259                 }
260         }
261 
262         /*
263          * Get the signal to deliver.  During the call to get_signal the
264          * debugger may change all our registers so we may need to revert
265          * the decision to restart the syscall; specifically, if the PC is
266          * changed, don't restart the syscall.
267          */
268         if (get_signal(&ksig)) {
269                 if (unlikely(restart) && regs->pc == restart_addr) {
270                         if (retval == -ERESTARTNOHAND ||
271                             retval == -ERESTART_RESTARTBLOCK
272                             || (retval == -ERESTARTSYS
273                                 && !(ksig.ka.sa.sa_flags & SA_RESTART))) {
274                                 /* No automatic restart */
275                                 regs->gpr[11] = -EINTR;
276                                 regs->pc = continue_addr;
277                         }
278                 }
279                 handle_signal(&ksig, regs);
280         } else {
281                 /* no handler */
282                 restore_saved_sigmask();
283                 /*
284                  * Restore pt_regs PC as syscall restart will be handled by
285                  * kernel without return to userspace
286                  */
287                 if (unlikely(restart) && regs->pc == restart_addr) {
288                         regs->pc = continue_addr;
289                         return restart;
290                 }
291         }
292 
293         return 0;
294 }
295 
296 asmlinkage int
297 do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
298 {
299         do {
300                 if (likely(thread_flags & _TIF_NEED_RESCHED)) {
301                         schedule();
302                 } else {
303                         if (unlikely(!user_mode(regs)))
304                                 return 0;
305                         local_irq_enable();
306                         if (thread_flags & _TIF_SIGPENDING) {
307                                 int restart = do_signal(regs, syscall);
308                                 if (unlikely(restart)) {
309                                         /*
310                                          * Restart without handlers.
311                                          * Deal with it without leaving
312                                          * the kernel space.
313                                          */
314                                         return restart;
315                                 }
316                                 syscall = 0;
317                         } else {
318                                 clear_thread_flag(TIF_NOTIFY_RESUME);
319                                 tracehook_notify_resume(regs);
320                         }
321                 }
322                 local_irq_disable();
323                 thread_flags = current_thread_info()->flags;
324         } while (thread_flags & _TIF_WORK_MASK);
325         return 0;
326 }
327 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp