[mirror_ubuntu-bionic-kernel.git] / arch / blackfin / kernel / signal.c

/*
 * Copyright 2004-2010 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later
 */

#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/ptrace.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <linux/sched/task_stack.h>

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

/* Location of the trace bit in SYSCFG. */
#define TRACE_BITS 0x0001

struct fdpic_func_descriptor {
	unsigned long	text;
	unsigned long	GOT;
};

struct rt_sigframe {
	int sig;
	struct siginfo *pinfo;
	void *puc;
	/* This is no longer needed by the kernel, but unfortunately userspace
	 * code expects it to be there.  */
	char retcode[8];
	struct siginfo info;
	struct ucontext uc;
};

static inline int
rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *pr0)
{
	unsigned long usp = 0;
	int err = 0;

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

#define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)

	/* restore passed registers */
	RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
	RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
	RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
	RESTORE(p4); RESTORE(p5);
	err |= __get_user(usp, &sc->sc_usp);
	wrusp(usp);
	RESTORE(a0w); RESTORE(a1w);
	RESTORE(a0x); RESTORE(a1x);
	RESTORE(astat);
	RESTORE(rets);
	RESTORE(pc);
	RESTORE(retx);
	RESTORE(fp);
	RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
	RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
	RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
	RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
	RESTORE(lc0); RESTORE(lc1);
	RESTORE(lt0); RESTORE(lt1);
	RESTORE(lb0); RESTORE(lb1);
	RESTORE(seqstat);

	regs->orig_p0 = -1;	/* disable syscall checks */

	*pr0 = regs->r0;
	return err;
}

asmlinkage int sys_rt_sigreturn(void)
{
	struct pt_regs *regs = current_pt_regs();
	unsigned long usp = rdusp();
	struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
	sigset_t set;
	int r0;

	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_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
		goto badframe;

	if (restore_altstack(&frame->uc.uc_stack))
		goto badframe;

	return r0;

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

static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
{
	int err = 0;

#define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)

	SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
	SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
	SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
	SETUP(p4); SETUP(p5);
	err |= __put_user(rdusp(), &sc->sc_usp);
	SETUP(a0w); SETUP(a1w);
	SETUP(a0x); SETUP(a1x);
	SETUP(astat);
	SETUP(rets);
	SETUP(pc);
	SETUP(retx);
	SETUP(fp);
	SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
	SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
	SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
	SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
	SETUP(lc0); SETUP(lc1);
	SETUP(lt0); SETUP(lt1);
	SETUP(lb0); SETUP(lb1);
	SETUP(seqstat);

	return err;
}

static inline void *get_sigframe(struct ksignal *ksig,
				 size_t frame_size)
{
	unsigned long usp = sigsp(rdusp(), ksig);

	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, sizeof(*frame));

	err |= __put_user(ksig->sig, &frame->sig);

	err |= __put_user(&frame->info, &frame->pinfo);
	err |= __put_user(&frame->uc, &frame->puc);
	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, rdusp());
	err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	if (err)
		return -EFAULT;

	/* Set up registers for signal handler */
	if (current->personality & FDPIC_FUNCPTRS) {
		struct fdpic_func_descriptor __user *funcptr =
			(struct fdpic_func_descriptor *) ksig->ka.sa.sa_handler;
		u32 pc, p3;
		err |= __get_user(pc, &funcptr->text);
		err |= __get_user(p3, &funcptr->GOT);
		if (err)
			return -EFAULT;
		regs->pc = pc;
		regs->p3 = p3;
	} else
		regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
	wrusp((unsigned long)frame);
	regs->rets = SIGRETURN_STUB;

	regs->r0 = frame->sig;
	regs->r1 = (unsigned long)(&frame->info);
	regs->r2 = (unsigned long)(&frame->uc);

	return 0;
}

static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
	switch (regs->r0) {
	case -ERESTARTNOHAND:
		if (!has_handler)
			goto do_restart;
		regs->r0 = -EINTR;
		break;

	case -ERESTARTSYS:
		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
			regs->r0 = -EINTR;
			break;
		}
		/* fallthrough */
	case -ERESTARTNOINTR:
 do_restart:
		regs->p0 = regs->orig_p0;
		regs->r0 = regs->orig_r0;
		regs->pc -= 2;
		break;

	case -ERESTART_RESTARTBLOCK:
		regs->p0 = __NR_restart_syscall;
		regs->pc -= 2;
		break;
	}
}

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

	/* are we from a system call? to see pt_regs->orig_p0 */
	if (regs->orig_p0 >= 0)
		/* If so, check system call restarting.. */
		handle_restart(regs, &ksig->ka, 1);

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

	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 *
 * Note that we go through the signals twice: once to check the signals
 * that the kernel can handle, and then we build all the user-level signal
 * handling stack-frames in one go after that.
 */
asmlinkage void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;

	current->thread.esp0 = (unsigned long)regs;

	if (get_signal(&ksig)) {
		/* Whee!  Actually deliver the signal.  */
		handle_signal(&ksig, regs);
		return;
	}

	/* Did we come from a system call? */
	if (regs->orig_p0 >= 0)
		/* Restart the system call - no handlers present */
		handle_restart(regs, NULL, 0);

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

/*
 * notification of userspace execution resumption
 */
asmlinkage void do_notify_resume(struct pt_regs *regs)
{
	if (test_thread_flag(TIF_SIGPENDING))
		do_signal(regs);

	if (test_thread_flag(TIF_NOTIFY_RESUME)) {
		clear_thread_flag(TIF_NOTIFY_RESUME);
		tracehook_notify_resume(regs);
	}
}
Commit	Line	Data
1394f032	1	/*
e8f263df	2	* Copyright 2004-2010 Analog Devices Inc.
1394f032	3	*
96f1050d	4	* Licensed under the GPL-2 or later
1394f032 BW	5	*/
	6
	7	#include <linux/signal.h>
	8	#include <linux/syscalls.h>
	9	#include <linux/ptrace.h>
	10	#include <linux/tty.h>
	11	#include <linux/personality.h>
	12	#include <linux/binfmts.h>
1f83b8f1	13	#include <linux/uaccess.h>
d1be2e48	14	#include <linux/tracehook.h>
68db0cf1	15	#include <linux/sched/task_stack.h>
1394f032	16
1394f032 BW	17	#include <asm/cacheflush.h>
1394f032 BW	18	#include <asm/ucontext.h>
697a9d65	19	#include <asm/fixed_code.h>
ddaebcab	20	#include <asm/syscall.h>
1394f032	21
8513c42e BS	22	/* Location of the trace bit in SYSCFG. */
	23	#define TRACE_BITS 0x0001
	24
1394f032 BW	25	struct fdpic_func_descriptor {
	26	unsigned long text;
	27	unsigned long GOT;
	28	};
	29
	30	struct rt_sigframe {
	31	int sig;
	32	struct siginfo *pinfo;
	33	void *puc;
697a9d65 BS	34	/* This is no longer needed by the kernel, but unfortunately userspace
697a9d65 BS	35	* code expects it to be there. */
1394f032 BW	36	char retcode[8];
	37	struct siginfo info;
	38	struct ucontext uc;
	39	};
	40
1394f032	41	static inline int
0ddeeca2	42	rt_restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc, int *pr0)
1394f032 BW	43	{
	44	unsigned long usp = 0;
	45	int err = 0;
	46
ddaebcab	47	/* Always make any pending restarted system calls return -EINTR */
f56141e3	48	current->restart_block.fn = do_no_restart_syscall;
ddaebcab	49
1394f032 BW	50	#define RESTORE(x) err \|= __get_user(regs->x, &sc->sc_##x)
	51
	52	/* restore passed registers */
	53	RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
	54	RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
	55	RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
	56	RESTORE(p4); RESTORE(p5);
	57	err \|= __get_user(usp, &sc->sc_usp);
	58	wrusp(usp);
	59	RESTORE(a0w); RESTORE(a1w);
	60	RESTORE(a0x); RESTORE(a1x);
	61	RESTORE(astat);
	62	RESTORE(rets);
	63	RESTORE(pc);
	64	RESTORE(retx);
	65	RESTORE(fp);
	66	RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
	67	RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
	68	RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
	69	RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
	70	RESTORE(lc0); RESTORE(lc1);
	71	RESTORE(lt0); RESTORE(lt1);
	72	RESTORE(lb0); RESTORE(lb1);
	73	RESTORE(seqstat);
	74
	75	regs->orig_p0 = -1; /* disable syscall checks */
	76
	77	*pr0 = regs->r0;
	78	return err;
	79	}
	80
135c37b8	81	asmlinkage int sys_rt_sigreturn(void)
1394f032	82	{
135c37b8	83	struct pt_regs *regs = current_pt_regs();
1394f032 BW	84	unsigned long usp = rdusp();
	85	struct rt_sigframe frame = (struct rt_sigframe )(usp);
	86	sigset_t set;
	87	int r0;
	88
	89	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	90	goto badframe;
	91	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	92	goto badframe;
	93
8e3f9f65	94	set_current_blocked(&set);
1394f032 BW	95
	96	if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
	97	goto badframe;
	98
79d43210	99	if (restore_altstack(&frame->uc.uc_stack))
1394f032 BW	100	goto badframe;
	101
	102	return r0;
	103
1f83b8f1	104	badframe:
1394f032 BW	105	force_sig(SIGSEGV, current);
	106	return 0;
	107	}
	108
	109	static inline int rt_setup_sigcontext(struct sigcontext sc, struct pt_regs regs)
	110	{
	111	int err = 0;
	112
	113	#define SETUP(x) err \|= __put_user(regs->x, &sc->sc_##x)
	114
	115	SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
	116	SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
	117	SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
	118	SETUP(p4); SETUP(p5);
	119	err \|= __put_user(rdusp(), &sc->sc_usp);
	120	SETUP(a0w); SETUP(a1w);
	121	SETUP(a0x); SETUP(a1x);
	122	SETUP(astat);
	123	SETUP(rets);
	124	SETUP(pc);
	125	SETUP(retx);
	126	SETUP(fp);
	127	SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
	128	SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
	129	SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
	130	SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
	131	SETUP(lc0); SETUP(lc1);
	132	SETUP(lt0); SETUP(lt1);
	133	SETUP(lb0); SETUP(lb1);
	134	SETUP(seqstat);
	135
	136	return err;
	137	}
	138
e90670a9	139	static inline void get_sigframe(struct ksignal ksig,
1394f032 BW	140	size_t frame_size)
1394f032 BW	141	{
e90670a9	142	unsigned long usp = sigsp(rdusp(), ksig);
1394f032	143
1394f032 BW	144	return (void *)((usp - frame_size) & -8UL);
	145	}
	146
	147	static int
1270cff1	148	setup_rt_frame(struct ksignal ksig, sigset_t set, struct pt_regs *regs)
1394f032 BW	149	{
	150	struct rt_sigframe *frame;
	151	int err = 0;
	152
e90670a9	153	frame = get_sigframe(ksig, sizeof(*frame));
1394f032	154
7bd83010	155	err \|= __put_user(ksig->sig, &frame->sig);
1394f032 BW	156
	157	err \|= __put_user(&frame->info, &frame->pinfo);
	158	err \|= __put_user(&frame->uc, &frame->puc);
1270cff1	159	err \|= copy_siginfo_to_user(&frame->info, &ksig->info);
1394f032 BW	160
	161	/* Create the ucontext. */
	162	err \|= __put_user(0, &frame->uc.uc_flags);
	163	err \|= __put_user(0, &frame->uc.uc_link);
79d43210	164	err \|= __save_altstack(&frame->uc.uc_stack, rdusp());
1394f032 BW	165	err \|= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
	166	err \|= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	167
1394f032	168	if (err)
29bf5dd8	169	return -EFAULT;
1394f032	170
1394f032	171	/* Set up registers for signal handler */
ecd0fa98	172	if (current->personality & FDPIC_FUNCPTRS) {
1394f032	173	struct fdpic_func_descriptor __user *funcptr =
1270cff1	174	(struct fdpic_func_descriptor *) ksig->ka.sa.sa_handler;
29bf5dd8 AV	175	u32 pc, p3;
	176	err \|= __get_user(pc, &funcptr->text);
	177	err \|= __get_user(p3, &funcptr->GOT);
	178	if (err)
	179	return -EFAULT;
	180	regs->pc = pc;
	181	regs->p3 = p3;
1394f032	182	} else
1270cff1	183	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
29bf5dd8	184	wrusp((unsigned long)frame);
697a9d65	185	regs->rets = SIGRETURN_STUB;
1394f032 BW	186
	187	regs->r0 = frame->sig;
	188	regs->r1 = (unsigned long)(&frame->info);
	189	regs->r2 = (unsigned long)(&frame->uc);
	190
	191	return 0;
1394f032 BW	192	}
	193
	194	static inline void
	195	handle_restart(struct pt_regs regs, struct k_sigaction ka, int has_handler)
	196	{
	197	switch (regs->r0) {
	198	case -ERESTARTNOHAND:
	199	if (!has_handler)
	200	goto do_restart;
	201	regs->r0 = -EINTR;
	202	break;
	203
	204	case -ERESTARTSYS:
	205	if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
	206	regs->r0 = -EINTR;
	207	break;
	208	}
	209	/* fallthrough */
	210	case -ERESTARTNOINTR:
1f83b8f1	211	do_restart:
1394f032 BW	212	regs->p0 = regs->orig_p0;
	213	regs->r0 = regs->orig_r0;
	214	regs->pc -= 2;
	215	break;
ddaebcab MF	216
	217	case -ERESTART_RESTARTBLOCK:
	218	regs->p0 = __NR_restart_syscall;
	219	regs->pc -= 2;
	220	break;
1394f032 BW	221	}
	222	}
	223
	224	/*
	225	* OK, we're invoking a handler
	226	*/
a610d6e6	227	static void
1270cff1	228	handle_signal(struct ksignal ksig, struct pt_regs regs)
1394f032	229	{
1270cff1 RW	230	int ret;
1270cff1 RW	231
1394f032 BW	232	/* are we from a system call? to see pt_regs->orig_p0 */
	233	if (regs->orig_p0 >= 0)
	234	/* If so, check system call restarting.. */
1270cff1	235	handle_restart(regs, &ksig->ka, 1);
1394f032 BW	236
1394f032 BW	237	/* set up the stack frame */
1270cff1 RW	238	ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
	239
	240	signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
1394f032 BW	241	}
	242
	243	/*
	244	* Note that 'init' is a special process: it doesn't get signals it doesn't
	245	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	246	* mistake.
	247	*
	248	* Note that we go through the signals twice: once to check the signals
	249	* that the kernel can handle, and then we build all the user-level signal
	250	* handling stack-frames in one go after that.
	251	*/
	252	asmlinkage void do_signal(struct pt_regs *regs)
	253	{
1270cff1	254	struct ksignal ksig;
1394f032 BW	255
	256	current->thread.esp0 = (unsigned long)regs;
	257
1270cff1	258	if (get_signal(&ksig)) {
1394f032	259	/* Whee! Actually deliver the signal. */
1270cff1	260	handle_signal(&ksig, regs);
1394f032 BW	261	return;
	262	}
	263
1394f032 BW	264	/* Did we come from a system call? */
	265	if (regs->orig_p0 >= 0)
	266	/* Restart the system call - no handlers present */
	267	handle_restart(regs, NULL, 0);
	268
	269	/* if there's no signal to deliver, we just put the saved sigmask
	270	* back */
51a7b448	271	restore_saved_sigmask();
1394f032	272	}
d1be2e48 BS	273
	274	/*
	275	* notification of userspace execution resumption
	276	*/
	277	asmlinkage void do_notify_resume(struct pt_regs *regs)
	278	{
6fd84c08	279	if (test_thread_flag(TIF_SIGPENDING))
d1be2e48 BS	280	do_signal(regs);
	281
	282	if (test_thread_flag(TIF_NOTIFY_RESUME)) {
	283	clear_thread_flag(TIF_NOTIFY_RESUME);
	284	tracehook_notify_resume(regs);
d1be2e48 BS	285	}
	286	}
	287