[deliverable/linux.git] / arch / parisc / kernel / ptrace.c

/*
 * Kernel support for the ptrace() and syscall tracing interfaces.
 *
 * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
 * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
 * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
 * Copyright (C) 2008 Helge Deller <deller@gmx.de>
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/personality.h>
#include <linux/security.h>
#include <linux/compat.h>
#include <linux/signal.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/processor.h>
#include <asm/asm-offsets.h>

/* PSW bits we allow the debugger to modify */
#define USER_PSW_BITS	(PSW_N | PSW_V | PSW_CB)

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *task)
{
	task->ptrace &= ~(PT_SINGLESTEP|PT_BLOCKSTEP);

	/* make sure the trap bits are not set */
	pa_psw(task)->r = 0;
	pa_psw(task)->t = 0;
	pa_psw(task)->h = 0;
	pa_psw(task)->l = 0;
}

/*
 * The following functions are called by ptrace_resume() when
 * enabling or disabling single/block tracing.
 */
void user_disable_single_step(struct task_struct *task)
{
	ptrace_disable(task);
}

void user_enable_single_step(struct task_struct *task)
{
	task->ptrace &= ~PT_BLOCKSTEP;
	task->ptrace |= PT_SINGLESTEP;

	if (pa_psw(task)->n) {
		struct siginfo si;

		/* Nullified, just crank over the queue. */
		task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
		task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
		task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
		pa_psw(task)->n = 0;
		pa_psw(task)->x = 0;
		pa_psw(task)->y = 0;
		pa_psw(task)->z = 0;
		pa_psw(task)->b = 0;
		ptrace_disable(task);
		/* Don't wake up the task, but let the
		   parent know something happened. */
		si.si_code = TRAP_TRACE;
		si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
		si.si_signo = SIGTRAP;
		si.si_errno = 0;
		force_sig_info(SIGTRAP, &si, task);
		/* notify_parent(task, SIGCHLD); */
		return;
	}

	/* Enable recovery counter traps.  The recovery counter
	 * itself will be set to zero on a task switch.  If the
	 * task is suspended on a syscall then the syscall return
	 * path will overwrite the recovery counter with a suitable
	 * value such that it traps once back in user space.  We
	 * disable interrupts in the tasks PSW here also, to avoid
	 * interrupts while the recovery counter is decrementing.
	 */
	pa_psw(task)->r = 1;
	pa_psw(task)->t = 0;
	pa_psw(task)->h = 0;
	pa_psw(task)->l = 0;
}

void user_enable_block_step(struct task_struct *task)
{
	task->ptrace &= ~PT_SINGLESTEP;
	task->ptrace |= PT_BLOCKSTEP;

	/* Enable taken branch trap. */
	pa_psw(task)->r = 0;
	pa_psw(task)->t = 1;
	pa_psw(task)->h = 0;
	pa_psw(task)->l = 0;
}

long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
	unsigned long tmp;
	long ret = -EIO;

	switch (request) {

	/* Read the word at location addr in the USER area.  For ptraced
	   processes, the kernel saves all regs on a syscall. */
	case PTRACE_PEEKUSR:
		if ((addr & (sizeof(long)-1)) ||
		    (unsigned long) addr >= sizeof(struct pt_regs))
			break;
		tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
		ret = put_user(tmp, (unsigned long *) data);
		break;

	/* Write the word at location addr in the USER area.  This will need
	   to change when the kernel no longer saves all regs on a syscall.
	   FIXME.  There is a problem at the moment in that r3-r18 are only
	   saved if the process is ptraced on syscall entry, and even then
	   those values are overwritten by actual register values on syscall
	   exit. */
	case PTRACE_POKEUSR:
		/* Some register values written here may be ignored in
		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
		 * r31/r31+4, and not with the values in pt_regs.
		 */
		if (addr == PT_PSW) {
			/* Allow writing to Nullify, Divide-step-correction,
			 * and carry/borrow bits.
			 * BEWARE, if you set N, and then single step, it won't
			 * stop on the nullified instruction.
			 */
			data &= USER_PSW_BITS;
			task_regs(child)->gr[0] &= ~USER_PSW_BITS;
			task_regs(child)->gr[0] |= data;
			ret = 0;
			break;
		}

		if ((addr & (sizeof(long)-1)) ||
		    (unsigned long) addr >= sizeof(struct pt_regs))
			break;
		if ((addr >= PT_GR1 && addr <= PT_GR31) ||
				addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
				(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
				addr == PT_SAR) {
			*(unsigned long *) ((char *) task_regs(child) + addr) = data;
			ret = 0;
		}
		break;

	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}


#ifdef CONFIG_COMPAT

/* This function is needed to translate 32 bit pt_regs offsets in to
 * 64 bit pt_regs offsets.  For example, a 32 bit gdb under a 64 bit kernel
 * will request offset 12 if it wants gr3, but the lower 32 bits of
 * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
 * This code relies on a 32 bit pt_regs being comprised of 32 bit values
 * except for the fp registers which (a) are 64 bits, and (b) follow
 * the gr registers at the start of pt_regs.  The 32 bit pt_regs should
 * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
 * being 64 bit in both cases.
 */

static long translate_usr_offset(long offset)
{
	if (offset < 0)
		return -1;
	else if (offset <= 32*4)	/* gr[0..31] */
		return offset * 2 + 4;
	else if (offset <= 32*4+32*8)	/* gr[0..31] + fr[0..31] */
		return offset + 32*4;
	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
		return offset * 2 + 4 - 32*8;
	else
		return -1;
}

long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
			compat_ulong_t addr, compat_ulong_t data)
{
	compat_uint_t tmp;
	long ret = -EIO;

	switch (request) {

	case PTRACE_PEEKUSR:
		if (addr & (sizeof(compat_uint_t)-1))
			break;
		addr = translate_usr_offset(addr);
		if (addr < 0)
			break;

		tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
		ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
		break;

	/* Write the word at location addr in the USER area.  This will need
	   to change when the kernel no longer saves all regs on a syscall.
	   FIXME.  There is a problem at the moment in that r3-r18 are only
	   saved if the process is ptraced on syscall entry, and even then
	   those values are overwritten by actual register values on syscall
	   exit. */
	case PTRACE_POKEUSR:
		/* Some register values written here may be ignored in
		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
		 * r31/r31+4, and not with the values in pt_regs.
		 */
		if (addr == PT_PSW) {
			/* Since PT_PSW==0, it is valid for 32 bit processes
			 * under 64 bit kernels as well.
			 */
			ret = arch_ptrace(child, request, addr, data);
		} else {
			if (addr & (sizeof(compat_uint_t)-1))
				break;
			addr = translate_usr_offset(addr);
			if (addr < 0)
				break;
			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
				/* Special case, fp regs are 64 bits anyway */
				*(__u64 *) ((char *) task_regs(child) + addr) = data;
				ret = 0;
			}
			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
					addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
					addr == PT_SAR+4) {
				/* Zero the top 32 bits */
				*(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
				*(__u32 *) ((char *) task_regs(child) + addr) = data;
				ret = 0;
			}
		}
		break;

	default:
		ret = compat_ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}
#endif


void syscall_trace(void)
{
	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;
	if (!(current->ptrace & PT_PTRACED))
		return;
	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
				 ? 0x80 : 0));
	/*
	 * this isn't the same as continuing with a signal, but it will do
	 * for normal use.  strace only continues with a signal if the
	 * stopping signal is not SIGTRAP.  -brl
	 */
	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Kernel support for the ptrace() and syscall tracing interfaces.
	3	*
	4	* Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
	5	* Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
	6	* Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
81e192d6	7	* Copyright (C) 2008 Helge Deller <deller@gmx.de>
1da177e4 LT	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/sched.h>
	12	#include <linux/mm.h>
	13	#include <linux/smp.h>
1da177e4 LT	14	#include <linux/errno.h>
	15	#include <linux/ptrace.h>
	16	#include <linux/user.h>
	17	#include <linux/personality.h>
	18	#include <linux/security.h>
	19	#include <linux/compat.h>
7ed20e1a	20	#include <linux/signal.h>
1da177e4 LT	21
	22	#include <asm/uaccess.h>
	23	#include <asm/pgtable.h>
	24	#include <asm/system.h>
	25	#include <asm/processor.h>
0013a854	26	#include <asm/asm-offsets.h>
1da177e4 LT	27
	28	/* PSW bits we allow the debugger to modify */
	29	#define USER_PSW_BITS (PSW_N \| PSW_V \| PSW_CB)
	30
81e192d6 HD	31	/*
	32	* Called by kernel/ptrace.c when detaching..
	33	*
	34	* Make sure single step bits etc are not set.
	35	*/
	36	void ptrace_disable(struct task_struct *task)
	37	{
	38	task->ptrace &= ~(PT_SINGLESTEP\|PT_BLOCKSTEP);
1da177e4	39
81e192d6 HD	40	/* make sure the trap bits are not set */
	41	pa_psw(task)->r = 0;
	42	pa_psw(task)->t = 0;
	43	pa_psw(task)->h = 0;
	44	pa_psw(task)->l = 0;
	45	}
	46
	47	/*
	48	* The following functions are called by ptrace_resume() when
	49	* enabling or disabling single/block tracing.
	50	*/
	51	void user_disable_single_step(struct task_struct *task)
	52	{
	53	ptrace_disable(task);
	54	}
	55
	56	void user_enable_single_step(struct task_struct *task)
	57	{
	58	task->ptrace &= ~PT_BLOCKSTEP;
	59	task->ptrace \|= PT_SINGLESTEP;
	60
	61	if (pa_psw(task)->n) {
	62	struct siginfo si;
	63
	64	/* Nullified, just crank over the queue. */
	65	task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
	66	task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
	67	task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
	68	pa_psw(task)->n = 0;
	69	pa_psw(task)->x = 0;
	70	pa_psw(task)->y = 0;
	71	pa_psw(task)->z = 0;
	72	pa_psw(task)->b = 0;
	73	ptrace_disable(task);
	74	/* Don't wake up the task, but let the
	75	parent know something happened. */
	76	si.si_code = TRAP_TRACE;
	77	si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
	78	si.si_signo = SIGTRAP;
	79	si.si_errno = 0;
	80	force_sig_info(SIGTRAP, &si, task);
	81	/* notify_parent(task, SIGCHLD); */
	82	return;
	83	}
	84
	85	/* Enable recovery counter traps. The recovery counter
	86	* itself will be set to zero on a task switch. If the
	87	* task is suspended on a syscall then the syscall return
	88	* path will overwrite the recovery counter with a suitable
	89	* value such that it traps once back in user space. We
	90	* disable interrupts in the tasks PSW here also, to avoid
	91	* interrupts while the recovery counter is decrementing.
	92	*/
	93	pa_psw(task)->r = 1;
	94	pa_psw(task)->t = 0;
	95	pa_psw(task)->h = 0;
	96	pa_psw(task)->l = 0;
	97	}
	98
	99	void user_enable_block_step(struct task_struct *task)
	100	{
	101	task->ptrace &= ~PT_SINGLESTEP;
	102	task->ptrace \|= PT_BLOCKSTEP;
	103
104	/* Enable taken branch trap. */
105	pa_psw(task)->r = 0;
106	pa_psw(task)->t = 1;
107	pa_psw(task)->h = 0;
108	pa_psw(task)->l = 0;
109	}
110
111	long arch_ptrace(struct task_struct *child, long request, long addr, long data)
112	{
113	unsigned long tmp;
114	long ret = -EIO;
1da177e4	115
81e192d6 HD	116	switch (request) {
	117
	118	/* Read the word at location addr in the USER area. For ptraced
	119	processes, the kernel saves all regs on a syscall. */
	120	case PTRACE_PEEKUSR:
	121	if ((addr & (sizeof(long)-1)) \|\|
	122	(unsigned long) addr >= sizeof(struct pt_regs))
	123	break;
	124	tmp = (unsigned long ) ((char *) task_regs(child) + addr);
	125	ret = put_user(tmp, (unsigned long *) data);
	126	break;
	127
	128	/* Write the word at location addr in the USER area. This will need
	129	to change when the kernel no longer saves all regs on a syscall.
	130	FIXME. There is a problem at the moment in that r3-r18 are only
	131	saved if the process is ptraced on syscall entry, and even then
	132	those values are overwritten by actual register values on syscall
	133	exit. */
	134	case PTRACE_POKEUSR:
	135	/* Some register values written here may be ignored in
	136	* entry.S:syscall_restore_rfi; e.g. iaoq is written with
	137	* r31/r31+4, and not with the values in pt_regs.
	138	*/
	139	if (addr == PT_PSW) {
	140	/* Allow writing to Nullify, Divide-step-correction,
	141	* and carry/borrow bits.
	142	* BEWARE, if you set N, and then single step, it won't
	143	* stop on the nullified instruction.
	144	*/
	145	data &= USER_PSW_BITS;
	146	task_regs(child)->gr[0] &= ~USER_PSW_BITS;
	147	task_regs(child)->gr[0] \|= data;
	148	ret = 0;
	149	break;
	150	}
	151
	152	if ((addr & (sizeof(long)-1)) \|\|
	153	(unsigned long) addr >= sizeof(struct pt_regs))
	154	break;
	155	if ((addr >= PT_GR1 && addr <= PT_GR31) \|\|
	156	addr == PT_IAOQ0 \|\| addr == PT_IAOQ1 \|\|
	157	(addr >= PT_FR0 && addr <= PT_FR31 + 4) \|\|
	158	addr == PT_SAR) {
	159	(unsigned long ) ((char *) task_regs(child) + addr) = data;
	160	ret = 0;
	161	}
	162	break;
	163
	164	default:
	165	ret = ptrace_request(child, request, addr, data);
	166	break;
	167	}
	168
	169	return ret;
	170	}
	171
	172
	173	#ifdef CONFIG_COMPAT
1da177e4 LT	174
	175	/* This function is needed to translate 32 bit pt_regs offsets in to
	176	* 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
	177	* will request offset 12 if it wants gr3, but the lower 32 bits of
	178	* the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
	179	* This code relies on a 32 bit pt_regs being comprised of 32 bit values
	180	* except for the fp registers which (a) are 64 bits, and (b) follow
	181	* the gr registers at the start of pt_regs. The 32 bit pt_regs should
	182	* be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
	183	* being 64 bit in both cases.
	184	*/
	185
	186	static long translate_usr_offset(long offset)
	187	{
	188	if (offset < 0)
	189	return -1;
	190	else if (offset <= 324) / gr[0..31] */
	191	return offset * 2 + 4;
	192	else if (offset <= 324+328) /* gr[0..31] + fr[0..31] */
	193	return offset + 32*4;
	194	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
	195	return offset * 2 + 4 - 32*8;
	196	else
	197	return -1;
	198	}
1da177e4	199
81e192d6 HD	200	long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
81e192d6 HD	201	compat_ulong_t addr, compat_ulong_t data)
1da177e4	202	{
81e192d6 HD	203	compat_uint_t tmp;
81e192d6 HD	204	long ret = -EIO;
1da177e4	205
1da177e4	206	switch (request) {
1da177e4	207
81e192d6 HD	208	case PTRACE_PEEKUSR:
	209	if (addr & (sizeof(compat_uint_t)-1))
	210	break;
	211	addr = translate_usr_offset(addr);
	212	if (addr < 0)
	213	break;
1da177e4	214
81e192d6 HD	215	tmp = (compat_uint_t ) ((char *) task_regs(child) + addr);
	216	ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
	217	break;
1da177e4 LT	218
	219	/* Write the word at location addr in the USER area. This will need
	220	to change when the kernel no longer saves all regs on a syscall.
	221	FIXME. There is a problem at the moment in that r3-r18 are only
	222	saved if the process is ptraced on syscall entry, and even then
	223	those values are overwritten by actual register values on syscall
	224	exit. */
	225	case PTRACE_POKEUSR:
1da177e4 LT	226	/* Some register values written here may be ignored in
	227	* entry.S:syscall_restore_rfi; e.g. iaoq is written with
	228	* r31/r31+4, and not with the values in pt_regs.
	229	*/
1da177e4	230	if (addr == PT_PSW) {
81e192d6 HD	231	/* Since PT_PSW==0, it is valid for 32 bit processes
81e192d6 HD	232	* under 64 bit kernels as well.
1da177e4	233	*/
81e192d6 HD	234	ret = arch_ptrace(child, request, addr, data);
	235	} else {
	236	if (addr & (sizeof(compat_uint_t)-1))
	237	break;
	238	addr = translate_usr_offset(addr);
	239	if (addr < 0)
	240	break;
1da177e4 LT	241	if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
1da177e4 LT	242	/* Special case, fp regs are 64 bits anyway */
81e192d6	243	(__u64 ) ((char *) task_regs(child) + addr) = data;
1da177e4 LT	244	ret = 0;
	245	}
	246	else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) \|\|
	247	addr == PT_IAOQ0+4 \|\| addr == PT_IAOQ1+4 \|\|
	248	addr == PT_SAR+4) {
	249	/* Zero the top 32 bits */
81e192d6 HD	250	(__u32 ) ((char *) task_regs(child) + addr - 4) = 0;
81e192d6 HD	251	(__u32 ) ((char *) task_regs(child) + addr) = data;
1da177e4 LT	252	ret = 0;
1da177e4 LT	253	}
1da177e4	254	}
81e192d6	255	break;
1da177e4 LT	256
1da177e4 LT	257	default:
81e192d6 HD	258	ret = compat_ptrace_request(child, request, addr, data);
81e192d6 HD	259	break;
1da177e4 LT	260	}
1da177e4 LT	261
1da177e4 LT	262	return ret;
1da177e4 LT	263	}
81e192d6 HD	264	#endif
81e192d6 HD	265
1da177e4 LT	266
	267	void syscall_trace(void)
	268	{
	269	if (!test_thread_flag(TIF_SYSCALL_TRACE))
	270	return;
	271	if (!(current->ptrace & PT_PTRACED))
	272	return;
	273	ptrace_notify(SIGTRAP \| ((current->ptrace & PT_TRACESYSGOOD)
	274	? 0x80 : 0));
	275	/*
	276	* this isn't the same as continuing with a signal, but it will do
	277	* for normal use. strace only continues with a signal if the
	278	* stopping signal is not SIGTRAP. -brl
	279	*/
	280	if (current->exit_code) {
	281	send_sig(current->exit_code, current, 1);
	282	current->exit_code = 0;
	283	}
	284	}