[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)
{
	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 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


void syscall_trace(int why)
{
	struct pt_regs *regs = &current->thread.regs;

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