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/Ethereal-msm8939-beta9/arch/microblaze/kernel/signal.c

https://bitbucket.org/MilosStamenkovic95/etherealos
C | 351 lines | 234 code | 53 blank | 64 comment | 24 complexity | 330130146f02bb3452814c55251296e0 MD5 | raw file
  1/*
  2 * Signal handling
  3 *
  4 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
  5 * Copyright (C) 2008-2009 PetaLogix
  6 * Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
  7 * Copyright (C) 2001 NEC Corporation
  8 * Copyright (C) 2001 Miles Bader <miles@gnu.org>
  9 * Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
 10 * Copyright (C) 1991,1992 Linus Torvalds
 11 *
 12 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
 13 *
 14 * This file was was derived from the sh version, arch/sh/kernel/signal.c
 15 *
 16 * This file is subject to the terms and conditions of the GNU General
 17 * Public License. See the file COPYING in the main directory of this
 18 * archive for more details.
 19 */
 20
 21#include <linux/sched.h>
 22#include <linux/mm.h>
 23#include <linux/smp.h>
 24#include <linux/kernel.h>
 25#include <linux/signal.h>
 26#include <linux/errno.h>
 27#include <linux/wait.h>
 28#include <linux/ptrace.h>
 29#include <linux/unistd.h>
 30#include <linux/stddef.h>
 31#include <linux/personality.h>
 32#include <linux/percpu.h>
 33#include <linux/linkage.h>
 34#include <linux/tracehook.h>
 35#include <asm/entry.h>
 36#include <asm/ucontext.h>
 37#include <linux/uaccess.h>
 38#include <asm/pgtable.h>
 39#include <asm/pgalloc.h>
 40#include <linux/syscalls.h>
 41#include <asm/cacheflush.h>
 42#include <asm/syscalls.h>
 43
 44/*
 45 * Do a signal return; undo the signal stack.
 46 */
 47struct sigframe {
 48	struct sigcontext sc;
 49	unsigned long extramask[_NSIG_WORDS-1];
 50	unsigned long tramp[2];	/* signal trampoline */
 51};
 52
 53struct rt_sigframe {
 54	struct siginfo info;
 55	struct ucontext uc;
 56	unsigned long tramp[2];	/* signal trampoline */
 57};
 58
 59static int restore_sigcontext(struct pt_regs *regs,
 60				struct sigcontext __user *sc, int *rval_p)
 61{
 62	unsigned int err = 0;
 63
 64#define COPY(x)		{err |= __get_user(regs->x, &sc->regs.x); }
 65	COPY(r0);
 66	COPY(r1);
 67	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
 68	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
 69	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
 70	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
 71	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
 72	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
 73	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
 74	COPY(r30);	COPY(r31);
 75	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
 76#undef COPY
 77
 78	*rval_p = regs->r3;
 79
 80	return err;
 81}
 82
 83asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
 84{
 85	struct rt_sigframe __user *frame =
 86		(struct rt_sigframe __user *)(regs->r1);
 87
 88	sigset_t set;
 89	int rval;
 90
 91	/* Always make any pending restarted system calls return -EINTR */
 92	current_thread_info()->restart_block.fn = do_no_restart_syscall;
 93
 94	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 95		goto badframe;
 96
 97	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 98		goto badframe;
 99
100	set_current_blocked(&set);
101
102	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &rval))
103		goto badframe;
104
105	if (restore_altstack(&frame->uc.uc_stack))
106		goto badframe;
107
108	return rval;
109
110badframe:
111	force_sig(SIGSEGV, current);
112	return 0;
113}
114
115/*
116 * Set up a signal frame.
117 */
118
119static int
120setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
121		unsigned long mask)
122{
123	int err = 0;
124
125#define COPY(x)		{err |= __put_user(regs->x, &sc->regs.x); }
126	COPY(r0);
127	COPY(r1);
128	COPY(r2);	COPY(r3);	COPY(r4);	COPY(r5);
129	COPY(r6);	COPY(r7);	COPY(r8);	COPY(r9);
130	COPY(r10);	COPY(r11);	COPY(r12);	COPY(r13);
131	COPY(r14);	COPY(r15);	COPY(r16);	COPY(r17);
132	COPY(r18);	COPY(r19);	COPY(r20);	COPY(r21);
133	COPY(r22);	COPY(r23);	COPY(r24);	COPY(r25);
134	COPY(r26);	COPY(r27);	COPY(r28);	COPY(r29);
135	COPY(r30);	COPY(r31);
136	COPY(pc);	COPY(ear);	COPY(esr);	COPY(fsr);
137#undef COPY
138
139	err |= __put_user(mask, &sc->oldmask);
140
141	return err;
142}
143
144/*
145 * Determine which stack to use..
146 */
147static inline void __user *
148get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
149{
150	/* Default to using normal stack */
151	unsigned long sp = regs->r1;
152
153	if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack(sp))
154		sp = current->sas_ss_sp + current->sas_ss_size;
155
156	return (void __user *)((sp - frame_size) & -8UL);
157}
158
159static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
160			sigset_t *set, struct pt_regs *regs)
161{
162	struct rt_sigframe __user *frame;
163	int err = 0;
164	int signal;
165	unsigned long address = 0;
166#ifdef CONFIG_MMU
167	pmd_t *pmdp;
168	pte_t *ptep;
169#endif
170
171	frame = get_sigframe(ka, regs, sizeof(*frame));
172
173	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
174		goto give_sigsegv;
175
176	signal = current_thread_info()->exec_domain
177		&& current_thread_info()->exec_domain->signal_invmap
178		&& sig < 32
179		? current_thread_info()->exec_domain->signal_invmap[sig]
180		: sig;
181
182	if (info)
183		err |= copy_siginfo_to_user(&frame->info, info);
184
185	/* Create the ucontext. */
186	err |= __put_user(0, &frame->uc.uc_flags);
187	err |= __put_user(NULL, &frame->uc.uc_link);
188	err |= __save_altstack(&frame->uc.uc_stack, regs->r1);
189	err |= setup_sigcontext(&frame->uc.uc_mcontext,
190			regs, set->sig[0]);
191	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
192
193	/* Set up to return from userspace. If provided, use a stub
194	 already in userspace. */
195	/* minus 8 is offset to cater for "rtsd r15,8" */
196	/* addi r12, r0, __NR_sigreturn */
197	err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
198			frame->tramp + 0);
199	/* brki r14, 0x8 */
200	err |= __put_user(0xb9cc0008, frame->tramp + 1);
201
202	/* Return from sighandler will jump to the tramp.
203	 Negative 8 offset because return is rtsd r15, 8 */
204	regs->r15 = ((unsigned long)frame->tramp)-8;
205
206	address = ((unsigned long)frame->tramp);
207#ifdef CONFIG_MMU
208	pmdp = pmd_offset(pud_offset(
209			pgd_offset(current->mm, address),
210					address), address);
211
212	preempt_disable();
213	ptep = pte_offset_map(pmdp, address);
214	if (pte_present(*ptep)) {
215		address = (unsigned long) page_address(pte_page(*ptep));
216		/* MS: I need add offset in page */
217		address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
218		/* MS address is virtual */
219		address = virt_to_phys(address);
220		invalidate_icache_range(address, address + 8);
221		flush_dcache_range(address, address + 8);
222	}
223	pte_unmap(ptep);
224	preempt_enable();
225#else
226	flush_icache_range(address, address + 8);
227	flush_dcache_range(address, address + 8);
228#endif
229	if (err)
230		goto give_sigsegv;
231
232	/* Set up registers for signal handler */
233	regs->r1 = (unsigned long) frame;
234
235	/* Signal handler args: */
236	regs->r5 = signal; /* arg 0: signum */
237	regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
238	regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
239	/* Offset to handle microblaze rtid r14, 0 */
240	regs->pc = (unsigned long)ka->sa.sa_handler;
241
242	set_fs(USER_DS);
243
244#ifdef DEBUG_SIG
245	pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
246		current->comm, current->pid, frame, regs->pc);
247#endif
248
249	return 0;
250
251give_sigsegv:
252	force_sigsegv(sig, current);
253	return -EFAULT;
254}
255
256/* Handle restarting system calls */
257static inline void
258handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
259{
260	switch (regs->r3) {
261	case -ERESTART_RESTARTBLOCK:
262	case -ERESTARTNOHAND:
263		if (!has_handler)
264			goto do_restart;
265		regs->r3 = -EINTR;
266		break;
267	case -ERESTARTSYS:
268		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
269			regs->r3 = -EINTR;
270			break;
271	}
272	/* fallthrough */
273	case -ERESTARTNOINTR:
274do_restart:
275		/* offset of 4 bytes to re-execute trap (brki) instruction */
276		regs->pc -= 4;
277		break;
278	}
279}
280
281/*
282 * OK, we're invoking a handler
283 */
284
285static void
286handle_signal(unsigned long sig, struct k_sigaction *ka,
287		siginfo_t *info, struct pt_regs *regs)
288{
289	sigset_t *oldset = sigmask_to_save();
290	int ret;
291
292	/* Set up the stack frame */
293	if (ka->sa.sa_flags & SA_SIGINFO)
294		ret = setup_rt_frame(sig, ka, info, oldset, regs);
295	else
296		ret = setup_rt_frame(sig, ka, NULL, oldset, regs);
297
298	if (ret)
299		return;
300
301	signal_delivered(sig, info, ka, regs,
302			test_thread_flag(TIF_SINGLESTEP));
303}
304
305/*
306 * Note that 'init' is a special process: it doesn't get signals it doesn't
307 * want to handle. Thus you cannot kill init even with a SIGKILL even by
308 * mistake.
309 *
310 * Note that we go through the signals twice: once to check the signals that
311 * the kernel can handle, and then we build all the user-level signal handling
312 * stack-frames in one go after that.
313 */
314static void do_signal(struct pt_regs *regs, int in_syscall)
315{
316	siginfo_t info;
317	int signr;
318	struct k_sigaction ka;
319#ifdef DEBUG_SIG
320	pr_info("do signal: %p %d\n", regs, in_syscall);
321	pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
322			regs->r12, current_thread_info()->flags);
323#endif
324
325	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
326	if (signr > 0) {
327		/* Whee! Actually deliver the signal. */
328		if (in_syscall)
329			handle_restart(regs, &ka, 1);
330		handle_signal(signr, &ka, &info, regs);
331		return;
332	}
333
334	if (in_syscall)
335		handle_restart(regs, NULL, 0);
336
337	/*
338	 * If there's no signal to deliver, we just put the saved sigmask
339	 * back.
340	 */
341	restore_saved_sigmask();
342}
343
344asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
345{
346	if (test_thread_flag(TIF_SIGPENDING))
347		do_signal(regs, in_syscall);
348
349	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
350		tracehook_notify_resume(regs);
351}