[linux-2.6-block.git] / arch / nios2 / kernel / signal.c

/*
 * Copyright (C) 2013-2014 Altera Corporation
 * Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
 * Copyright (C) 2004 Microtronix Datacom Ltd
 * Copyright (C) 1991, 1992 Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/uaccess.h>
#include <linux/unistd.h>
#include <linux/personality.h>
#include <linux/tracehook.h>

#include <asm/ucontext.h>
#include <asm/cacheflush.h>

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

/*
 * Do a signal return; undo the signal stack.
 *
 * Keep the return code on the stack quadword aligned!
 * That makes the cache flush below easier.
 */

struct rt_sigframe {
	struct siginfo info;
	struct ucontext uc;
};

static inline int rt_restore_ucontext(struct pt_regs *regs,
					struct switch_stack *sw,
					struct ucontext *uc, int *pr2)
{
	int temp;
	greg_t *gregs = uc->uc_mcontext.gregs;
	int err;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	err = __get_user(temp, &uc->uc_mcontext.version);
	if (temp != MCONTEXT_VERSION)
		goto badframe;
	/* restore passed registers */
	err |= __get_user(regs->r1, &gregs[0]);
	err |= __get_user(regs->r2, &gregs[1]);
	err |= __get_user(regs->r3, &gregs[2]);
	err |= __get_user(regs->r4, &gregs[3]);
	err |= __get_user(regs->r5, &gregs[4]);
	err |= __get_user(regs->r6, &gregs[5]);
	err |= __get_user(regs->r7, &gregs[6]);
	err |= __get_user(regs->r8, &gregs[7]);
	err |= __get_user(regs->r9, &gregs[8]);
	err |= __get_user(regs->r10, &gregs[9]);
	err |= __get_user(regs->r11, &gregs[10]);
	err |= __get_user(regs->r12, &gregs[11]);
	err |= __get_user(regs->r13, &gregs[12]);
	err |= __get_user(regs->r14, &gregs[13]);
	err |= __get_user(regs->r15, &gregs[14]);
	err |= __get_user(sw->r16, &gregs[15]);
	err |= __get_user(sw->r17, &gregs[16]);
	err |= __get_user(sw->r18, &gregs[17]);
	err |= __get_user(sw->r19, &gregs[18]);
	err |= __get_user(sw->r20, &gregs[19]);
	err |= __get_user(sw->r21, &gregs[20]);
	err |= __get_user(sw->r22, &gregs[21]);
	err |= __get_user(sw->r23, &gregs[22]);
	/* gregs[23] is handled below */
	err |= __get_user(sw->fp, &gregs[24]);  /* Verify, should this be
							settable */
	err |= __get_user(sw->gp, &gregs[25]);  /* Verify, should this be
							settable */

	err |= __get_user(temp, &gregs[26]);  /* Not really necessary no user
							settable bits */
	err |= __get_user(regs->ea, &gregs[27]);

	err |= __get_user(regs->ra, &gregs[23]);
	err |= __get_user(regs->sp, &gregs[28]);

	regs->orig_r2 = -1;		/* disable syscall checks */

	err |= restore_altstack(&uc->uc_stack);
	if (err)
		goto badframe;

	*pr2 = regs->r2;
	return err;

badframe:
	return 1;
}

asmlinkage int do_rt_sigreturn(struct switch_stack *sw)
{
	struct pt_regs *regs = (struct pt_regs *)(sw + 1);
	/* Verify, can we follow the stack back */
	struct rt_sigframe *frame = (struct rt_sigframe *) regs->sp;
	sigset_t set;
	int rval;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;

	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	set_current_blocked(&set);

	if (rt_restore_ucontext(regs, sw, &frame->uc, &rval))
		goto badframe;

	return rval;

badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

static inline int rt_setup_ucontext(struct ucontext *uc, struct pt_regs *regs)
{
	struct switch_stack *sw = (struct switch_stack *)regs - 1;
	greg_t *gregs = uc->uc_mcontext.gregs;
	int err = 0;

	err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
	err |= __put_user(regs->r1, &gregs[0]);
	err |= __put_user(regs->r2, &gregs[1]);
	err |= __put_user(regs->r3, &gregs[2]);
	err |= __put_user(regs->r4, &gregs[3]);
	err |= __put_user(regs->r5, &gregs[4]);
	err |= __put_user(regs->r6, &gregs[5]);
	err |= __put_user(regs->r7, &gregs[6]);
	err |= __put_user(regs->r8, &gregs[7]);
	err |= __put_user(regs->r9, &gregs[8]);
	err |= __put_user(regs->r10, &gregs[9]);
	err |= __put_user(regs->r11, &gregs[10]);
	err |= __put_user(regs->r12, &gregs[11]);
	err |= __put_user(regs->r13, &gregs[12]);
	err |= __put_user(regs->r14, &gregs[13]);
	err |= __put_user(regs->r15, &gregs[14]);
	err |= __put_user(sw->r16, &gregs[15]);
	err |= __put_user(sw->r17, &gregs[16]);
	err |= __put_user(sw->r18, &gregs[17]);
	err |= __put_user(sw->r19, &gregs[18]);
	err |= __put_user(sw->r20, &gregs[19]);
	err |= __put_user(sw->r21, &gregs[20]);
	err |= __put_user(sw->r22, &gregs[21]);
	err |= __put_user(sw->r23, &gregs[22]);
	err |= __put_user(regs->ra, &gregs[23]);
	err |= __put_user(sw->fp, &gregs[24]);
	err |= __put_user(sw->gp, &gregs[25]);
	err |= __put_user(regs->ea, &gregs[27]);
	err |= __put_user(regs->sp, &gregs[28]);
	return err;
}

static inline void *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
				 size_t frame_size)
{
	unsigned long usp;

	/* Default to using normal stack.  */
	usp = regs->sp;

	/* This is the X/Open sanctioned signal stack switching.  */
	usp = sigsp(usp, ksig);

	/* Verify, is it 32 or 64 bit aligned */
	return (void *)((usp - frame_size) & -8UL);
}

static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
			  struct pt_regs *regs)
{
	struct rt_sigframe *frame;
	int err = 0;

	frame = get_sigframe(ksig, regs, sizeof(*frame));

	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
		err |= copy_siginfo_to_user(&frame->info, &ksig->info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
	err |= rt_setup_ucontext(&frame->uc, regs);
	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace; jump to fixed address sigreturn
	   trampoline on kuser page.  */
	regs->ra = (unsigned long) (0x1044);

	/* Set up registers for signal handler */
	regs->sp = (unsigned long) frame;
	regs->r4 = (unsigned long) ksig->sig;
	regs->r5 = (unsigned long) &frame->info;
	regs->r6 = (unsigned long) &frame->uc;
	regs->ea = (unsigned long) ksig->ka.sa.sa_handler;
	return 0;

give_sigsegv:
	force_sigsegv(ksig->sig, current);
	return -EFAULT;
}

/*
 * OK, we're invoking a handler
 */
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
	int ret;
	sigset_t *oldset = sigmask_to_save();

	/* set up the stack frame */
	ret = setup_rt_frame(ksig, oldset, regs);

	signal_setup_done(ret, ksig, 0);
}

static int do_signal(struct pt_regs *regs)
{
	unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
	int restart = 0;
	struct ksignal ksig;

	current->thread.kregs = regs;

	/*
	 * If we were from a system call, check for system call restarting...
	 */
	if (regs->orig_r2 >= 0) {
		continue_addr = regs->ea;
		restart_addr = continue_addr - 4;
		retval = regs->r2;

		/*
		 * Prepare for system call restart. We do this here so that a
		 * debugger will see the already changed PC.
		 */
		switch (retval) {
		case ERESTART_RESTARTBLOCK:
			restart = -2;
		case ERESTARTNOHAND:
		case ERESTARTSYS:
		case ERESTARTNOINTR:
			restart++;
			regs->r2 = regs->orig_r2;
			regs->r7 = regs->orig_r7;
			regs->ea = restart_addr;
			break;
		}
	}

	if (get_signal(&ksig)) {
		/* handler */
		if (unlikely(restart && regs->ea == restart_addr)) {
			if (retval == ERESTARTNOHAND ||
			    retval == ERESTART_RESTARTBLOCK ||
			     (retval == ERESTARTSYS
				&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
				regs->r2 = EINTR;
				regs->r7 = 1;
				regs->ea = continue_addr;
			}
		}
		handle_signal(&ksig, regs);
		return 0;
	}

	/*
	 * No handler present
	 */
	if (unlikely(restart) && regs->ea == restart_addr) {
		regs->ea = continue_addr;
		regs->r2 = __NR_restart_syscall;
	}

	/*
	* If there's no signal to deliver, we just put the saved sigmask back.
	*/
	restore_saved_sigmask();

	return restart;
}

asmlinkage int do_notify_resume(struct pt_regs *regs)
{
	/*
	 * We want the common case to go fast, which is why we may in certain
	 * cases get here from kernel mode. Just return without doing anything
	 * if so.
	 */
	if (!user_mode(regs))
		return 0;

	if (test_thread_flag(TIF_SIGPENDING)) {
		int restart = do_signal(regs);

		if (unlikely(restart)) {
			/*
			 * Restart without handlers.
			 * Deal with it without leaving
			 * the kernel space.
			 */
			return restart;
		}
	} else if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
		tracehook_notify_resume(regs);

	return 0;
}
Commit	Line	Data
b53e906d LFT	1	/*
	2	* Copyright (C) 2013-2014 Altera Corporation
	3	* Copyright (C) 2011-2012 Tobias Klauser <tklauser@distanz.ch>
	4	* Copyright (C) 2004 Microtronix Datacom Ltd
	5	* Copyright (C) 1991, 1992 Linus Torvalds
	6	*
	7	* This file is subject to the terms and conditions of the GNU General Public
	8	* License. See the file COPYING in the main directory of this archive
	9	* for more details.
	10	*/
	11
	12	#include <linux/signal.h>
	13	#include <linux/errno.h>
	14	#include <linux/ptrace.h>
	15	#include <linux/uaccess.h>
	16	#include <linux/unistd.h>
	17	#include <linux/personality.h>
	18	#include <linux/tracehook.h>
	19
	20	#include <asm/ucontext.h>
	21	#include <asm/cacheflush.h>
	22
	23	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
	24
	25	/*
	26	* Do a signal return; undo the signal stack.
	27	*
	28	* Keep the return code on the stack quadword aligned!
	29	* That makes the cache flush below easier.
	30	*/
	31
	32	struct rt_sigframe {
	33	struct siginfo info;
	34	struct ucontext uc;
	35	};
	36
	37	static inline int rt_restore_ucontext(struct pt_regs *regs,
	38	struct switch_stack *sw,
	39	struct ucontext uc, int pr2)
	40	{
	41	int temp;
	42	greg_t *gregs = uc->uc_mcontext.gregs;
	43	int err;
	44
	45	/* Always make any pending restarted system calls return -EINTR */
	46	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	47
	48	err = __get_user(temp, &uc->uc_mcontext.version);
	49	if (temp != MCONTEXT_VERSION)
	50	goto badframe;
	51	/* restore passed registers */
	52	err \|= __get_user(regs->r1, &gregs[0]);
	53	err \|= __get_user(regs->r2, &gregs[1]);
	54	err \|= __get_user(regs->r3, &gregs[2]);
	55	err \|= __get_user(regs->r4, &gregs[3]);
	56	err \|= __get_user(regs->r5, &gregs[4]);
	57	err \|= __get_user(regs->r6, &gregs[5]);
	58	err \|= __get_user(regs->r7, &gregs[6]);
	59	err \|= __get_user(regs->r8, &gregs[7]);
	60	err \|= __get_user(regs->r9, &gregs[8]);
	61	err \|= __get_user(regs->r10, &gregs[9]);
	62	err \|= __get_user(regs->r11, &gregs[10]);
	63	err \|= __get_user(regs->r12, &gregs[11]);
	64	err \|= __get_user(regs->r13, &gregs[12]);
65	err \|= __get_user(regs->r14, &gregs[13]);
66	err \|= __get_user(regs->r15, &gregs[14]);
67	err \|= __get_user(sw->r16, &gregs[15]);
68	err \|= __get_user(sw->r17, &gregs[16]);
69	err \|= __get_user(sw->r18, &gregs[17]);
70	err \|= __get_user(sw->r19, &gregs[18]);
71	err \|= __get_user(sw->r20, &gregs[19]);
72	err \|= __get_user(sw->r21, &gregs[20]);
73	err \|= __get_user(sw->r22, &gregs[21]);
74	err \|= __get_user(sw->r23, &gregs[22]);
75	/* gregs[23] is handled below */
76	err \|= __get_user(sw->fp, &gregs[24]); /* Verify, should this be
77	settable */
78	err \|= __get_user(sw->gp, &gregs[25]); /* Verify, should this be
79	settable */
80
81	err \|= __get_user(temp, &gregs[26]); /* Not really necessary no user
82	settable bits */
83	err \|= __get_user(regs->ea, &gregs[27]);
84
85	err \|= __get_user(regs->ra, &gregs[23]);
86	err \|= __get_user(regs->sp, &gregs[28]);
87
88	regs->orig_r2 = -1; /* disable syscall checks */
89
90	err \|= restore_altstack(&uc->uc_stack);
91	if (err)
92	goto badframe;
93
94	*pr2 = regs->r2;
95	return err;
96
97	badframe:
98	return 1;
99	}
100
101	asmlinkage int do_rt_sigreturn(struct switch_stack *sw)
102	{
103	struct pt_regs regs = (struct pt_regs )(sw + 1);
104	/* Verify, can we follow the stack back */
105	struct rt_sigframe frame = (struct rt_sigframe ) regs->sp;
106	sigset_t set;
107	int rval;
108
109	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
110	goto badframe;
111
112	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
113	goto badframe;
114
115	set_current_blocked(&set);
116
117	if (rt_restore_ucontext(regs, sw, &frame->uc, &rval))
118	goto badframe;
119
120	return rval;
121
122	badframe:
123	force_sig(SIGSEGV, current);
124	return 0;
125	}
126
127	static inline int rt_setup_ucontext(struct ucontext uc, struct pt_regs regs)
128	{
129	struct switch_stack sw = (struct switch_stack )regs - 1;
130	greg_t *gregs = uc->uc_mcontext.gregs;
131	int err = 0;
132
133	err \|= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
134	err \|= __put_user(regs->r1, &gregs[0]);
135	err \|= __put_user(regs->r2, &gregs[1]);
136	err \|= __put_user(regs->r3, &gregs[2]);
137	err \|= __put_user(regs->r4, &gregs[3]);
138	err \|= __put_user(regs->r5, &gregs[4]);
139	err \|= __put_user(regs->r6, &gregs[5]);
140	err \|= __put_user(regs->r7, &gregs[6]);
141	err \|= __put_user(regs->r8, &gregs[7]);
142	err \|= __put_user(regs->r9, &gregs[8]);
143	err \|= __put_user(regs->r10, &gregs[9]);
144	err \|= __put_user(regs->r11, &gregs[10]);
145	err \|= __put_user(regs->r12, &gregs[11]);
146	err \|= __put_user(regs->r13, &gregs[12]);
147	err \|= __put_user(regs->r14, &gregs[13]);
148	err \|= __put_user(regs->r15, &gregs[14]);
149	err \|= __put_user(sw->r16, &gregs[15]);
150	err \|= __put_user(sw->r17, &gregs[16]);
151	err \|= __put_user(sw->r18, &gregs[17]);
152	err \|= __put_user(sw->r19, &gregs[18]);
153	err \|= __put_user(sw->r20, &gregs[19]);
154	err \|= __put_user(sw->r21, &gregs[20]);
155	err \|= __put_user(sw->r22, &gregs[21]);
156	err \|= __put_user(sw->r23, &gregs[22]);
157	err \|= __put_user(regs->ra, &gregs[23]);
158	err \|= __put_user(sw->fp, &gregs[24]);
159	err \|= __put_user(sw->gp, &gregs[25]);
160	err \|= __put_user(regs->ea, &gregs[27]);
161	err \|= __put_user(regs->sp, &gregs[28]);
162	return err;
163	}
164
165	static inline void get_sigframe(struct ksignal ksig, struct pt_regs *regs,
166	size_t frame_size)
167	{
168	unsigned long usp;
169
170	/* Default to using normal stack. */
171	usp = regs->sp;
172
173	/* This is the X/Open sanctioned signal stack switching. */
174	usp = sigsp(usp, ksig);
175
176	/* Verify, is it 32 or 64 bit aligned */
177	return (void *)((usp - frame_size) & -8UL);
178	}
179
180	static int setup_rt_frame(struct ksignal ksig, sigset_t set,
181	struct pt_regs *regs)
182	{
183	struct rt_sigframe *frame;
184	int err = 0;
185
186	frame = get_sigframe(ksig, regs, sizeof(*frame));
187
188	if (ksig->ka.sa.sa_flags & SA_SIGINFO)
189	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
190
191	/* Create the ucontext. */
192	err \|= __put_user(0, &frame->uc.uc_flags);
193	err \|= __put_user(0, &frame->uc.uc_link);
194	err \|= __save_altstack(&frame->uc.uc_stack, regs->sp);
195	err \|= rt_setup_ucontext(&frame->uc, regs);
196	err \|= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
197
198	if (err)
199	goto give_sigsegv;
200
201	/* Set up to return from userspace; jump to fixed address sigreturn
202	trampoline on kuser page. */
d24c8163	203	regs->ra = (unsigned long) (0x1044);
b53e906d LFT	204
	205	/* Set up registers for signal handler */
	206	regs->sp = (unsigned long) frame;
	207	regs->r4 = (unsigned long) ksig->sig;
	208	regs->r5 = (unsigned long) &frame->info;
	209	regs->r6 = (unsigned long) &frame->uc;
	210	regs->ea = (unsigned long) ksig->ka.sa.sa_handler;
	211	return 0;
	212
	213	give_sigsegv:
	214	force_sigsegv(ksig->sig, current);
	215	return -EFAULT;
	216	}
	217
	218	/*
	219	* OK, we're invoking a handler
	220	*/
	221	static void handle_signal(struct ksignal ksig, struct pt_regs regs)
	222	{
	223	int ret;
	224	sigset_t *oldset = sigmask_to_save();
	225
	226	/* set up the stack frame */
	227	ret = setup_rt_frame(ksig, oldset, regs);
	228
	229	signal_setup_done(ret, ksig, 0);
	230	}
	231
	232	static int do_signal(struct pt_regs *regs)
	233	{
	234	unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
	235	int restart = 0;
	236	struct ksignal ksig;
	237
	238	current->thread.kregs = regs;
	239
	240	/*
	241	* If we were from a system call, check for system call restarting...
	242	*/
	243	if (regs->orig_r2 >= 0) {
	244	continue_addr = regs->ea;
	245	restart_addr = continue_addr - 4;
	246	retval = regs->r2;
	247
	248	/*
	249	* Prepare for system call restart. We do this here so that a
	250	* debugger will see the already changed PC.
	251	*/
	252	switch (retval) {
	253	case ERESTART_RESTARTBLOCK:
	254	restart = -2;
	255	case ERESTARTNOHAND:
	256	case ERESTARTSYS:
	257	case ERESTARTNOINTR:
	258	restart++;
	259	regs->r2 = regs->orig_r2;
	260	regs->r7 = regs->orig_r7;
	261	regs->ea = restart_addr;
	262	break;
	263	}
	264	}
	265
	266	if (get_signal(&ksig)) {
	267	/* handler */
268	if (unlikely(restart && regs->ea == restart_addr)) {
269	if (retval == ERESTARTNOHAND \|\|
270	retval == ERESTART_RESTARTBLOCK \|\|
271	(retval == ERESTARTSYS
272	&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
273	regs->r2 = EINTR;
274	regs->r7 = 1;
275	regs->ea = continue_addr;
276	}
277	}
278	handle_signal(&ksig, regs);
279	return 0;
280	}
281
282	/*
283	* No handler present
284	*/
285	if (unlikely(restart) && regs->ea == restart_addr) {
286	regs->ea = continue_addr;
287	regs->r2 = __NR_restart_syscall;
288	}
289
290	/*
291	* If there's no signal to deliver, we just put the saved sigmask back.
292	*/
293	restore_saved_sigmask();
294
295	return restart;
296	}
297
298	asmlinkage int do_notify_resume(struct pt_regs *regs)
299	{
300	/*
301	* We want the common case to go fast, which is why we may in certain
302	* cases get here from kernel mode. Just return without doing anything
303	* if so.
304	*/
305	if (!user_mode(regs))
306	return 0;
307
308	if (test_thread_flag(TIF_SIGPENDING)) {
309	int restart = do_signal(regs);
310
311	if (unlikely(restart)) {
312	/*
313	* Restart without handlers.
314	* Deal with it without leaving
315	* the kernel space.
316	*/
317	return restart;
318	}
319	} else if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME))
320	tracehook_notify_resume(regs);
321
322	return 0;
323	}