[net-next-2.6.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/tracehook.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)
{
	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
	clear_tsk_thread_flag(task, TIF_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)
{
	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
	set_tsk_thread_flag(task, TIF_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)
{
	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
	set_tsk_thread_flag(task, TIF_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,
		 unsigned long addr, unsigned 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(unsigned long)-1)) ||
		     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(unsigned long)-1)) ||
		     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 compat_ulong_t translate_usr_offset(compat_ulong_t offset)
{
	if (offset < 0)
		return sizeof(struct pt_regs);
	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 sizeof(struct pt_regs);
}

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 >= sizeof(struct pt_regs))
			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 >= sizeof(struct pt_regs))
				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

long do_syscall_trace_enter(struct pt_regs *regs)
{
	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
	    tracehook_report_syscall_entry(regs))
		return -1L;

	return regs->gr[20];
}

void do_syscall_trace_exit(struct pt_regs *regs)
{
	int stepping = test_thread_flag(TIF_SINGLESTEP) ||
		test_thread_flag(TIF_BLOCKSTEP);

	if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
		tracehook_report_syscall_exit(regs, stepping);
}
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>
1da177e4 LT	15	#include <linux/ptrace.h>
d6b58772	16	#include <linux/tracehook.h>
1da177e4 LT	17	#include <linux/user.h>
	18	#include <linux/personality.h>
	19	#include <linux/security.h>
	20	#include <linux/compat.h>
7ed20e1a	21	#include <linux/signal.h>
1da177e4 LT	22
	23	#include <asm/uaccess.h>
	24	#include <asm/pgtable.h>
	25	#include <asm/system.h>
	26	#include <asm/processor.h>
0013a854	27	#include <asm/asm-offsets.h>
1da177e4 LT	28
	29	/* PSW bits we allow the debugger to modify */
	30	#define USER_PSW_BITS (PSW_N \| PSW_V \| PSW_CB)
	31
81e192d6 HD	32	/*
	33	* Called by kernel/ptrace.c when detaching..
	34	*
	35	* Make sure single step bits etc are not set.
	36	*/
	37	void ptrace_disable(struct task_struct *task)
	38	{
ecd3d4bc KM	39	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
ecd3d4bc KM	40	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
1da177e4	41
81e192d6 HD	42	/* make sure the trap bits are not set */
	43	pa_psw(task)->r = 0;
	44	pa_psw(task)->t = 0;
	45	pa_psw(task)->h = 0;
	46	pa_psw(task)->l = 0;
	47	}
	48
	49	/*
	50	* The following functions are called by ptrace_resume() when
	51	* enabling or disabling single/block tracing.
	52	*/
	53	void user_disable_single_step(struct task_struct *task)
	54	{
	55	ptrace_disable(task);
	56	}
	57
	58	void user_enable_single_step(struct task_struct *task)
	59	{
ecd3d4bc KM	60	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
ecd3d4bc KM	61	set_tsk_thread_flag(task, TIF_SINGLESTEP);
81e192d6 HD	62
	63	if (pa_psw(task)->n) {
	64	struct siginfo si;
	65
	66	/* Nullified, just crank over the queue. */
	67	task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
	68	task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
	69	task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
	70	pa_psw(task)->n = 0;
	71	pa_psw(task)->x = 0;
	72	pa_psw(task)->y = 0;
	73	pa_psw(task)->z = 0;
	74	pa_psw(task)->b = 0;
	75	ptrace_disable(task);
	76	/* Don't wake up the task, but let the
	77	parent know something happened. */
	78	si.si_code = TRAP_TRACE;
	79	si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
	80	si.si_signo = SIGTRAP;
	81	si.si_errno = 0;
	82	force_sig_info(SIGTRAP, &si, task);
	83	/* notify_parent(task, SIGCHLD); */
	84	return;
	85	}
	86
	87	/* Enable recovery counter traps. The recovery counter
	88	* itself will be set to zero on a task switch. If the
	89	* task is suspended on a syscall then the syscall return
	90	* path will overwrite the recovery counter with a suitable
	91	* value such that it traps once back in user space. We
	92	* disable interrupts in the tasks PSW here also, to avoid
	93	* interrupts while the recovery counter is decrementing.
	94	*/
	95	pa_psw(task)->r = 1;
	96	pa_psw(task)->t = 0;
	97	pa_psw(task)->h = 0;
	98	pa_psw(task)->l = 0;
	99	}
	100
	101	void user_enable_block_step(struct task_struct *task)
	102	{
ecd3d4bc KM	103	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
ecd3d4bc KM	104	set_tsk_thread_flag(task, TIF_BLOCKSTEP);
81e192d6 HD	105
	106	/* Enable taken branch trap. */
	107	pa_psw(task)->r = 0;
	108	pa_psw(task)->t = 1;
	109	pa_psw(task)->h = 0;
	110	pa_psw(task)->l = 0;
	111	}
	112
9b05a69e NK	113	long arch_ptrace(struct task_struct *child, long request,
9b05a69e NK	114	unsigned long addr, unsigned long data)
81e192d6 HD	115	{
	116	unsigned long tmp;
	117	long ret = -EIO;
1da177e4	118
81e192d6 HD	119	switch (request) {
	120
	121	/* Read the word at location addr in the USER area. For ptraced
	122	processes, the kernel saves all regs on a syscall. */
	123	case PTRACE_PEEKUSR:
9b05a69e NK	124	if ((addr & (sizeof(unsigned long)-1)) \|\|
9b05a69e NK	125	addr >= sizeof(struct pt_regs))
81e192d6 HD	126	break;
	127	tmp = (unsigned long ) ((char *) task_regs(child) + addr);
	128	ret = put_user(tmp, (unsigned long *) data);
	129	break;
	130
	131	/* Write the word at location addr in the USER area. This will need
	132	to change when the kernel no longer saves all regs on a syscall.
	133	FIXME. There is a problem at the moment in that r3-r18 are only
	134	saved if the process is ptraced on syscall entry, and even then
	135	those values are overwritten by actual register values on syscall
	136	exit. */
	137	case PTRACE_POKEUSR:
	138	/* Some register values written here may be ignored in
	139	* entry.S:syscall_restore_rfi; e.g. iaoq is written with
	140	* r31/r31+4, and not with the values in pt_regs.
	141	*/
	142	if (addr == PT_PSW) {
	143	/* Allow writing to Nullify, Divide-step-correction,
	144	* and carry/borrow bits.
	145	* BEWARE, if you set N, and then single step, it won't
	146	* stop on the nullified instruction.
	147	*/
	148	data &= USER_PSW_BITS;
	149	task_regs(child)->gr[0] &= ~USER_PSW_BITS;
	150	task_regs(child)->gr[0] \|= data;
	151	ret = 0;
	152	break;
	153	}
	154
9b05a69e NK	155	if ((addr & (sizeof(unsigned long)-1)) \|\|
9b05a69e NK	156	addr >= sizeof(struct pt_regs))
81e192d6 HD	157	break;
	158	if ((addr >= PT_GR1 && addr <= PT_GR31) \|\|
	159	addr == PT_IAOQ0 \|\| addr == PT_IAOQ1 \|\|
	160	(addr >= PT_FR0 && addr <= PT_FR31 + 4) \|\|
	161	addr == PT_SAR) {
	162	(unsigned long ) ((char *) task_regs(child) + addr) = data;
	163	ret = 0;
	164	}
	165	break;
	166
	167	default:
	168	ret = ptrace_request(child, request, addr, data);
	169	break;
	170	}
	171
	172	return ret;
	173	}
	174
	175
	176	#ifdef CONFIG_COMPAT
1da177e4 LT	177
	178	/* This function is needed to translate 32 bit pt_regs offsets in to
	179	* 64 bit pt_regs offsets. For example, a 32 bit gdb under a 64 bit kernel
	180	* will request offset 12 if it wants gr3, but the lower 32 bits of
	181	* the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
	182	* This code relies on a 32 bit pt_regs being comprised of 32 bit values
	183	* except for the fp registers which (a) are 64 bits, and (b) follow
	184	* the gr registers at the start of pt_regs. The 32 bit pt_regs should
	185	* be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
	186	* being 64 bit in both cases.
	187	*/
	188
ed79b86d	189	static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
1da177e4 LT	190	{
1da177e4 LT	191	if (offset < 0)
ed79b86d	192	return sizeof(struct pt_regs);
1da177e4 LT	193	else if (offset <= 324) / gr[0..31] */
	194	return offset * 2 + 4;
	195	else if (offset <= 324+328) /* gr[0..31] + fr[0..31] */
	196	return offset + 32*4;
	197	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
	198	return offset * 2 + 4 - 32*8;
	199	else
ed79b86d	200	return sizeof(struct pt_regs);
1da177e4	201	}
1da177e4	202
81e192d6 HD	203	long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
81e192d6 HD	204	compat_ulong_t addr, compat_ulong_t data)
1da177e4	205	{
81e192d6 HD	206	compat_uint_t tmp;
81e192d6 HD	207	long ret = -EIO;
1da177e4	208
1da177e4	209	switch (request) {
1da177e4	210
81e192d6 HD	211	case PTRACE_PEEKUSR:
	212	if (addr & (sizeof(compat_uint_t)-1))
	213	break;
	214	addr = translate_usr_offset(addr);
ed79b86d	215	if (addr >= sizeof(struct pt_regs))
81e192d6	216	break;
1da177e4	217
81e192d6 HD	218	tmp = (compat_uint_t ) ((char *) task_regs(child) + addr);
	219	ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
	220	break;
1da177e4 LT	221
	222	/* Write the word at location addr in the USER area. This will need
	223	to change when the kernel no longer saves all regs on a syscall.
	224	FIXME. There is a problem at the moment in that r3-r18 are only
	225	saved if the process is ptraced on syscall entry, and even then
	226	those values are overwritten by actual register values on syscall
	227	exit. */
	228	case PTRACE_POKEUSR:
1da177e4 LT	229	/* Some register values written here may be ignored in
	230	* entry.S:syscall_restore_rfi; e.g. iaoq is written with
	231	* r31/r31+4, and not with the values in pt_regs.
	232	*/
1da177e4	233	if (addr == PT_PSW) {
81e192d6 HD	234	/* Since PT_PSW==0, it is valid for 32 bit processes
81e192d6 HD	235	* under 64 bit kernels as well.
1da177e4	236	*/
81e192d6 HD	237	ret = arch_ptrace(child, request, addr, data);
	238	} else {
	239	if (addr & (sizeof(compat_uint_t)-1))
	240	break;
	241	addr = translate_usr_offset(addr);
ed79b86d	242	if (addr >= sizeof(struct pt_regs))
81e192d6	243	break;
1da177e4 LT	244	if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
1da177e4 LT	245	/* Special case, fp regs are 64 bits anyway */
81e192d6	246	(__u64 ) ((char *) task_regs(child) + addr) = data;
1da177e4 LT	247	ret = 0;
	248	}
	249	else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) \|\|
	250	addr == PT_IAOQ0+4 \|\| addr == PT_IAOQ1+4 \|\|
	251	addr == PT_SAR+4) {
	252	/* Zero the top 32 bits */
81e192d6 HD	253	(__u32 ) ((char *) task_regs(child) + addr - 4) = 0;
81e192d6 HD	254	(__u32 ) ((char *) task_regs(child) + addr) = data;
1da177e4 LT	255	ret = 0;
1da177e4 LT	256	}
1da177e4	257	}
81e192d6	258	break;
1da177e4 LT	259
1da177e4 LT	260	default:
81e192d6 HD	261	ret = compat_ptrace_request(child, request, addr, data);
81e192d6 HD	262	break;
1da177e4 LT	263	}
1da177e4 LT	264
1da177e4 LT	265	return ret;
1da177e4 LT	266	}
81e192d6 HD	267	#endif
81e192d6 HD	268
2798af1a KM	269	long do_syscall_trace_enter(struct pt_regs *regs)
	270	{
	271	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
	272	tracehook_report_syscall_entry(regs))
	273	return -1L;
	274
	275	return regs->gr[20];
	276	}
1da177e4	277
2798af1a	278	void do_syscall_trace_exit(struct pt_regs *regs)
1da177e4	279	{
ecd3d4bc KM	280	int stepping = test_thread_flag(TIF_SINGLESTEP) \|\|
ecd3d4bc KM	281	test_thread_flag(TIF_BLOCKSTEP);
d6b58772	282
2798af1a KM	283	if (stepping \|\| test_thread_flag(TIF_SYSCALL_TRACE))
2798af1a KM	284	tracehook_report_syscall_exit(regs, stepping);
1da177e4	285	}