[mirror_ubuntu-artful-kernel.git] / arch / tile / kernel / ptrace.c

/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 *
 * Copied from i386: Ross Biro 1/23/92
 */

#include <linux/kernel.h>
#include <linux/ptrace.h>
#include <linux/kprobes.h>
#include <linux/compat.h>
#include <linux/uaccess.h>
#include <linux/regset.h>
#include <linux/elf.h>
#include <linux/tracehook.h>
#include <linux/context_tracking.h>
#include <linux/sched/task_stack.h>

#include <asm/traps.h>
#include <arch/chip.h>

#define CREATE_TRACE_POINTS
#include <trace/events/syscalls.h>

void user_enable_single_step(struct task_struct *child)
{
	set_tsk_thread_flag(child, TIF_SINGLESTEP);
}

void user_disable_single_step(struct task_struct *child)
{
	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
}

/*
 * Called by kernel/ptrace.c when detaching..
 */
void ptrace_disable(struct task_struct *child)
{
	clear_tsk_thread_flag(child, TIF_SINGLESTEP);

	/*
	 * These two are currently unused, but will be set by arch_ptrace()
	 * and used in the syscall assembly when we do support them.
	 */
	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}

/*
 * Get registers from task and ready the result for userspace.
 * Note that we localize the API issues to getregs() and putregs() at
 * some cost in performance, e.g. we need a full pt_regs copy for
 * PEEKUSR, and two copies for POKEUSR.  But in general we expect
 * GETREGS/PUTREGS to be the API of choice anyway.
 */
static char *getregs(struct task_struct *child, struct pt_regs *uregs)
{
	*uregs = *task_pt_regs(child);

	/* Set up flags ABI bits. */
	uregs->flags = 0;
#ifdef CONFIG_COMPAT
	if (task_thread_info(child)->status & TS_COMPAT)
		uregs->flags |= PT_FLAGS_COMPAT;
#endif

	return (char *)uregs;
}

/* Put registers back to task. */
static void putregs(struct task_struct *child, struct pt_regs *uregs)
{
	struct pt_regs *regs = task_pt_regs(child);

	/* Don't allow overwriting the kernel-internal flags word. */
	uregs->flags = regs->flags;

	/* Only allow setting the ICS bit in the ex1 word. */
	uregs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(uregs->ex1));

	*regs = *uregs;
}

enum tile_regset {
	REGSET_GPR,
};

static int tile_gpr_get(struct task_struct *target,
			  const struct user_regset *regset,
			  unsigned int pos, unsigned int count,
			  void *kbuf, void __user *ubuf)
{
	struct pt_regs regs;

	getregs(target, &regs);

	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &regs, 0,
				   sizeof(regs));
}

static int tile_gpr_set(struct task_struct *target,
			  const struct user_regset *regset,
			  unsigned int pos, unsigned int count,
			  const void *kbuf, const void __user *ubuf)
{
	int ret;
	struct pt_regs regs = *task_pt_regs(target);

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &regs, 0,
				 sizeof(regs));
	if (ret)
		return ret;

	putregs(target, &regs);

	return 0;
}

static const struct user_regset tile_user_regset[] = {
	[REGSET_GPR] = {
		.core_note_type = NT_PRSTATUS,
		.n = ELF_NGREG,
		.size = sizeof(elf_greg_t),
		.align = sizeof(elf_greg_t),
		.get = tile_gpr_get,
		.set = tile_gpr_set,
	},
};

static const struct user_regset_view tile_user_regset_view = {
	.name = CHIP_ARCH_NAME,
	.e_machine = ELF_ARCH,
	.ei_osabi = ELF_OSABI,
	.regsets = tile_user_regset,
	.n = ARRAY_SIZE(tile_user_regset),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
	return &tile_user_regset_view;
}

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	unsigned long __user *datap = (long __user __force *)data;
	unsigned long tmp;
	long ret = -EIO;
	char *childreg;
	struct pt_regs copyregs;

	switch (request) {

	case PTRACE_PEEKUSR:  /* Read register from pt_regs. */
		if (addr >= PTREGS_SIZE)
			break;
		childreg = getregs(child, &copyregs) + addr;
#ifdef CONFIG_COMPAT
		if (is_compat_task()) {
			if (addr & (sizeof(compat_long_t)-1))
				break;
			ret = put_user(*(compat_long_t *)childreg,
				       (compat_long_t __user *)datap);
		} else
#endif
		{
			if (addr & (sizeof(long)-1))
				break;
			ret = put_user(*(long *)childreg, datap);
		}
		break;

	case PTRACE_POKEUSR:  /* Write register in pt_regs. */
		if (addr >= PTREGS_SIZE)
			break;
		childreg = getregs(child, &copyregs) + addr;
#ifdef CONFIG_COMPAT
		if (is_compat_task()) {
			if (addr & (sizeof(compat_long_t)-1))
				break;
			*(compat_long_t *)childreg = data;
		} else
#endif
		{
			if (addr & (sizeof(long)-1))
				break;
			*(long *)childreg = data;
		}
		putregs(child, &copyregs);
		ret = 0;
		break;

	case PTRACE_GETREGS:  /* Get all registers from the child. */
		ret = copy_regset_to_user(child, &tile_user_regset_view,
					  REGSET_GPR, 0,
					  sizeof(struct pt_regs), datap);
		break;

	case PTRACE_SETREGS:  /* Set all registers in the child. */
		ret = copy_regset_from_user(child, &tile_user_regset_view,
					    REGSET_GPR, 0,
					    sizeof(struct pt_regs), datap);
		break;

	case PTRACE_GETFPREGS:  /* Get the child FPU state. */
	case PTRACE_SETFPREGS:  /* Set the child FPU state. */
		break;

	case PTRACE_SETOPTIONS:
		/* Support TILE-specific ptrace options. */
		BUILD_BUG_ON(PTRACE_O_MASK_TILE & PTRACE_O_MASK);
		tmp = data & PTRACE_O_MASK_TILE;
		data &= ~PTRACE_O_MASK_TILE;
		ret = ptrace_request(child, request, addr, data);
		if (ret == 0) {
			unsigned int flags = child->ptrace;
			flags &= ~(PTRACE_O_MASK_TILE << PT_OPT_FLAG_SHIFT);
			flags |= (tmp << PT_OPT_FLAG_SHIFT);
			child->ptrace = flags;
		}
		break;

	default:
#ifdef CONFIG_COMPAT
		if (task_thread_info(current)->status & TS_COMPAT) {
			ret = compat_ptrace_request(child, request,
						    addr, data);
			break;
		}
#endif
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}

#ifdef CONFIG_COMPAT
/* Not used; we handle compat issues in arch_ptrace() directly. */
long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
			       compat_ulong_t addr, compat_ulong_t data)
{
	BUG();
}
#endif

int do_syscall_trace_enter(struct pt_regs *regs)
{
	u32 work = ACCESS_ONCE(current_thread_info()->flags);

	if ((work & _TIF_SYSCALL_TRACE) &&
	    tracehook_report_syscall_entry(regs)) {
		regs->regs[TREG_SYSCALL_NR] = -1;
		return -1;
	}

	if (secure_computing(NULL) == -1)
		return -1;

	if (work & _TIF_SYSCALL_TRACEPOINT)
		trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);

	return regs->regs[TREG_SYSCALL_NR];
}

void do_syscall_trace_exit(struct pt_regs *regs)
{
	long errno;

	/*
	 * The standard tile calling convention returns the value (or negative
	 * errno) in r0, and zero (or positive errno) in r1.
	 * It saves a couple of cycles on the hot path to do this work in
	 * registers only as we return, rather than updating the in-memory
	 * struct ptregs.
	 */
	errno = (long) regs->regs[0];
	if (errno < 0 && errno > -4096)
		regs->regs[1] = -errno;
	else
		regs->regs[1] = 0;

	if (test_thread_flag(TIF_SYSCALL_TRACE))
		tracehook_report_syscall_exit(regs, 0);

	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
		trace_sys_exit(regs, regs->regs[0]);
}

void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs)
{
	struct siginfo info;

	memset(&info, 0, sizeof(info));
	info.si_signo = SIGTRAP;
	info.si_code  = TRAP_BRKPT;
	info.si_addr  = (void __user *) regs->pc;

	/* Send us the fakey SIGTRAP */
	force_sig_info(SIGTRAP, &info, tsk);
}

/* Handle synthetic interrupt delivered only by the simulator. */
void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
{
	send_sigtrap(current, regs);
}
Commit	Line	Data
867e359b CM	1	/*
	2	* Copyright 2010 Tilera Corporation. All Rights Reserved.
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License
	6	* as published by the Free Software Foundation, version 2.
	7	*
	8	* This program is distributed in the hope that it will be useful, but
	9	* WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	11	* NON INFRINGEMENT. See the GNU General Public License for
	12	* more details.
	13	*
	14	* Copied from i386: Ross Biro 1/23/92
	15	*/
	16
	17	#include <linux/kernel.h>
	18	#include <linux/ptrace.h>
	19	#include <linux/kprobes.h>
	20	#include <linux/compat.h>
	21	#include <linux/uaccess.h>
7be68284 SM	22	#include <linux/regset.h>
7be68284 SM	23	#include <linux/elf.h>
ef182724	24	#include <linux/tracehook.h>
49e4e156	25	#include <linux/context_tracking.h>
68db0cf1 IM	26	#include <linux/sched/task_stack.h>
68db0cf1 IM	27
0707ad30	28	#include <asm/traps.h>
7be68284	29	#include <arch/chip.h>
867e359b	30
ef567f25 SM	31	#define CREATE_TRACE_POINTS
	32	#include <trace/events/syscalls.h>
	33
867e359b CM	34	void user_enable_single_step(struct task_struct *child)
	35	{
	36	set_tsk_thread_flag(child, TIF_SINGLESTEP);
	37	}
	38
	39	void user_disable_single_step(struct task_struct *child)
	40	{
	41	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
	42	}
	43
867e359b CM	44	/*
	45	* Called by kernel/ptrace.c when detaching..
	46	*/
	47	void ptrace_disable(struct task_struct *child)
	48	{
	49	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
	50
	51	/*
	52	* These two are currently unused, but will be set by arch_ptrace()
	53	* and used in the syscall assembly when we do support them.
	54	*/
	55	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
	56	}
	57
cb67e161 CM	58	/*
	59	* Get registers from task and ready the result for userspace.
	60	* Note that we localize the API issues to getregs() and putregs() at
	61	* some cost in performance, e.g. we need a full pt_regs copy for
	62	* PEEKUSR, and two copies for POKEUSR. But in general we expect
	63	* GETREGS/PUTREGS to be the API of choice anyway.
	64	*/
	65	static char getregs(struct task_struct child, struct pt_regs *uregs)
	66	{
	67	uregs = task_pt_regs(child);
	68
	69	/* Set up flags ABI bits. */
	70	uregs->flags = 0;
	71	#ifdef CONFIG_COMPAT
	72	if (task_thread_info(child)->status & TS_COMPAT)
	73	uregs->flags \|= PT_FLAGS_COMPAT;
	74	#endif
	75
	76	return (char *)uregs;
	77	}
	78
	79	/* Put registers back to task. */
	80	static void putregs(struct task_struct child, struct pt_regs uregs)
	81	{
	82	struct pt_regs *regs = task_pt_regs(child);
	83
	84	/* Don't allow overwriting the kernel-internal flags word. */
	85	uregs->flags = regs->flags;
	86
	87	/* Only allow setting the ICS bit in the ex1 word. */
	88	uregs->ex1 = PL_ICS_EX1(USER_PL, EX1_ICS(uregs->ex1));
	89
	90	regs = uregs;
	91	}
	92
7be68284 SM	93	enum tile_regset {
	94	REGSET_GPR,
	95	};
	96
	97	static int tile_gpr_get(struct task_struct *target,
	98	const struct user_regset *regset,
	99	unsigned int pos, unsigned int count,
	100	void kbuf, void __user ubuf)
	101	{
	102	struct pt_regs regs;
	103
	104	getregs(target, &regs);
	105
	106	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &regs, 0,
	107	sizeof(regs));
	108	}
	109
	110	static int tile_gpr_set(struct task_struct *target,
	111	const struct user_regset *regset,
	112	unsigned int pos, unsigned int count,
	113	const void kbuf, const void __user ubuf)
	114	{
	115	int ret;
fd7c9914	116	struct pt_regs regs = *task_pt_regs(target);
7be68284 SM	117
	118	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &regs, 0,
	119	sizeof(regs));
	120	if (ret)
	121	return ret;
	122
	123	putregs(target, &regs);
	124
	125	return 0;
	126	}
	127
	128	static const struct user_regset tile_user_regset[] = {
	129	[REGSET_GPR] = {
	130	.core_note_type = NT_PRSTATUS,
	131	.n = ELF_NGREG,
	132	.size = sizeof(elf_greg_t),
	133	.align = sizeof(elf_greg_t),
	134	.get = tile_gpr_get,
	135	.set = tile_gpr_set,
	136	},
	137	};
	138
	139	static const struct user_regset_view tile_user_regset_view = {
	140	.name = CHIP_ARCH_NAME,
	141	.e_machine = ELF_ARCH,
	142	.ei_osabi = ELF_OSABI,
	143	.regsets = tile_user_regset,
	144	.n = ARRAY_SIZE(tile_user_regset),
	145	};
	146
	147	const struct user_regset_view task_user_regset_view(struct task_struct task)
	148	{
	149	return &tile_user_regset_view;
	150	}
	151
9b05a69e NK	152	long arch_ptrace(struct task_struct *child, long request,
9b05a69e NK	153	unsigned long addr, unsigned long data)
867e359b	154	{
ce7f2a39	155	unsigned long __user datap = (long __user __force )data;
867e359b	156	unsigned long tmp;
867e359b	157	long ret = -EIO;
ce7f2a39	158	char *childreg;
1deb9c5d	159	struct pt_regs copyregs;
867e359b CM	160
	161	switch (request) {
	162
	163	case PTRACE_PEEKUSR: /* Read register from pt_regs. */
8c0acac3	164	if (addr >= PTREGS_SIZE)
867e359b	165	break;
cb67e161	166	childreg = getregs(child, &copyregs) + addr;
ce7f2a39 CM	167	#ifdef CONFIG_COMPAT
	168	if (is_compat_task()) {
	169	if (addr & (sizeof(compat_long_t)-1))
	170	break;
	171	ret = put_user((compat_long_t )childreg,
	172	(compat_long_t __user *)datap);
	173	} else
	174	#endif
	175	{
	176	if (addr & (sizeof(long)-1))
	177	break;
	178	ret = put_user((long )childreg, datap);
	179	}
867e359b CM	180	break;
	181
	182	case PTRACE_POKEUSR: /* Write register in pt_regs. */
8c0acac3	183	if (addr >= PTREGS_SIZE)
867e359b	184	break;
cb67e161	185	childreg = getregs(child, &copyregs) + addr;
ce7f2a39 CM	186	#ifdef CONFIG_COMPAT
	187	if (is_compat_task()) {
	188	if (addr & (sizeof(compat_long_t)-1))
	189	break;
	190	(compat_long_t )childreg = data;
	191	} else
	192	#endif
	193	{
	194	if (addr & (sizeof(long)-1))
	195	break;
	196	(long )childreg = data;
	197	}
cb67e161	198	putregs(child, &copyregs);
bcd97c3f	199	ret = 0;
867e359b CM	200	break;
	201
	202	case PTRACE_GETREGS: /* Get all registers from the child. */
9af62547 SM	203	ret = copy_regset_to_user(child, &tile_user_regset_view,
	204	REGSET_GPR, 0,
	205	sizeof(struct pt_regs), datap);
867e359b CM	206	break;
	207
	208	case PTRACE_SETREGS: /* Set all registers in the child. */
9af62547 SM	209	ret = copy_regset_from_user(child, &tile_user_regset_view,
	210	REGSET_GPR, 0,
	211	sizeof(struct pt_regs), datap);
867e359b CM	212	break;
	213
	214	case PTRACE_GETFPREGS: /* Get the child FPU state. */
	215	case PTRACE_SETFPREGS: /* Set the child FPU state. */
	216	break;
	217
	218	case PTRACE_SETOPTIONS:
	219	/* Support TILE-specific ptrace options. */
395e095e	220	BUILD_BUG_ON(PTRACE_O_MASK_TILE & PTRACE_O_MASK);
867e359b CM	221	tmp = data & PTRACE_O_MASK_TILE;
	222	data &= ~PTRACE_O_MASK_TILE;
	223	ret = ptrace_request(child, request, addr, data);
395e095e CM	224	if (ret == 0) {
	225	unsigned int flags = child->ptrace;
	226	flags &= ~(PTRACE_O_MASK_TILE << PT_OPT_FLAG_SHIFT);
	227	flags \|= (tmp << PT_OPT_FLAG_SHIFT);
	228	child->ptrace = flags;
	229	}
867e359b CM	230	break;
	231
	232	default:
	233	#ifdef CONFIG_COMPAT
	234	if (task_thread_info(current)->status & TS_COMPAT) {
	235	ret = compat_ptrace_request(child, request,
	236	addr, data);
	237	break;
	238	}
	239	#endif
	240	ret = ptrace_request(child, request, addr, data);
	241	break;
	242	}
	243
	244	return ret;
	245	}
	246
	247	#ifdef CONFIG_COMPAT
	248	/* Not used; we handle compat issues in arch_ptrace() directly. */
	249	long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
	250	compat_ulong_t addr, compat_ulong_t data)
	251	{
	252	BUG();
	253	}
	254	#endif
	255
ef182724	256	int do_syscall_trace_enter(struct pt_regs *regs)
867e359b	257	{
49e4e156 CM	258	u32 work = ACCESS_ONCE(current_thread_info()->flags);
49e4e156 CM	259
635efc70 KC	260	if ((work & _TIF_SYSCALL_TRACE) &&
	261	tracehook_report_syscall_entry(regs)) {
	262	regs->regs[TREG_SYSCALL_NR] = -1;
a0ddef81	263	return -1;
ef182724	264	}
867e359b	265
635efc70 KC	266	if (secure_computing(NULL) == -1)
	267	return -1;
	268
49e4e156	269	if (work & _TIF_SYSCALL_TRACEPOINT)
ef567f25 SM	270	trace_sys_enter(regs, regs->regs[TREG_SYSCALL_NR]);
ef567f25 SM	271
ef182724 SM	272	return regs->regs[TREG_SYSCALL_NR];
ef182724 SM	273	}
867e359b	274
ef182724 SM	275	void do_syscall_trace_exit(struct pt_regs *regs)
ef182724 SM	276	{
9b5bbf72 CM	277	long errno;
	278
	279	/*
	280	* The standard tile calling convention returns the value (or negative
	281	* errno) in r0, and zero (or positive errno) in r1.
	282	* It saves a couple of cycles on the hot path to do this work in
	283	* registers only as we return, rather than updating the in-memory
	284	* struct ptregs.
	285	*/
	286	errno = (long) regs->regs[0];
	287	if (errno < 0 && errno > -4096)
	288	regs->regs[1] = -errno;
	289	else
	290	regs->regs[1] = 0;
	291
ef567f25 SM	292	if (test_thread_flag(TIF_SYSCALL_TRACE))
	293	tracehook_report_syscall_exit(regs, 0);
	294
	295	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
9fc1894c	296	trace_sys_exit(regs, regs->regs[0]);
867e359b CM	297	}
867e359b CM	298
2f9ac29e	299	void send_sigtrap(struct task_struct tsk, struct pt_regs regs)
867e359b CM	300	{
	301	struct siginfo info;
	302
	303	memset(&info, 0, sizeof(info));
	304	info.si_signo = SIGTRAP;
	305	info.si_code = TRAP_BRKPT;
	306	info.si_addr = (void __user *) regs->pc;
	307
	308	/* Send us the fakey SIGTRAP */
	309	force_sig_info(SIGTRAP, &info, tsk);
	310	}
	311
	312	/* Handle synthetic interrupt delivered only by the simulator. */
	313	void __kprobes do_breakpoint(struct pt_regs* regs, int fault_num)
	314	{
2f9ac29e	315	send_sigtrap(current, regs);
867e359b	316	}