sparc/kernel/ptrace_64.c

// SPDX-License-Identifier: GPL-2.0-only
/* ptrace.c: Sparc process tracing support.
 *
 * Copyright (C) 1996, 2008 David S. Miller (davem@davemloft.net)
 * Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 *
 * Based upon code written by Ross Biro, Linus Torvalds, Bob Manson,
 * and David Mosberger.
 *
 * Added Linux support -miguel (weird, eh?, the original code was meant
 * to emulate SunOS).
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/seccomp.h>
#include <linux/audit.h>
#include <linux/signal.h>
#include <linux/regset.h>
#include <linux/tracehook.h>
#include <trace/syscall.h>
#include <linux/compat.h>
#include <linux/elf.h>
#include <linux/context_tracking.h>

#include <asm/asi.h>
#include <linux/uaccess.h>
#include <asm/psrcompat.h>
#include <asm/visasm.h>
#include <asm/spitfire.h>
#include <asm/page.h>
#include <asm/cpudata.h>
#include <asm/cacheflush.h>

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

#include "entry.h"

/* #define ALLOW_INIT_TRACING */

struct pt_regs_offset {
	const char *name;
	int offset;
};

#define REG_OFFSET_NAME(n, r) \
	{.name = n, .offset = (PT_V9_##r)}
#define REG_OFFSET_END {.name = NULL, .offset = 0}

static const struct pt_regs_offset regoffset_table[] = {
	REG_OFFSET_NAME("g0", G0),
	REG_OFFSET_NAME("g1", G1),
	REG_OFFSET_NAME("g2", G2),
	REG_OFFSET_NAME("g3", G3),
	REG_OFFSET_NAME("g4", G4),
	REG_OFFSET_NAME("g5", G5),
	REG_OFFSET_NAME("g6", G6),
	REG_OFFSET_NAME("g7", G7),

	REG_OFFSET_NAME("i0", I0),
	REG_OFFSET_NAME("i1", I1),
	REG_OFFSET_NAME("i2", I2),
	REG_OFFSET_NAME("i3", I3),
	REG_OFFSET_NAME("i4", I4),
	REG_OFFSET_NAME("i5", I5),
	REG_OFFSET_NAME("i6", I6),
	REG_OFFSET_NAME("i7", I7),

	REG_OFFSET_NAME("tstate", TSTATE),
	REG_OFFSET_NAME("pc", TPC),
	REG_OFFSET_NAME("npc", TNPC),
	REG_OFFSET_NAME("y", Y),
	REG_OFFSET_NAME("lr", I7),

	REG_OFFSET_END,
};

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* nothing to do */
}

/* To get the necessary page struct, access_process_vm() first calls
 * get_user_pages().  This has done a flush_dcache_page() on the
 * accessed page.  Then our caller (copy_{to,from}_user_page()) did
 * to memcpy to read/write the data from that page.
 *
 * Now, the only thing we have to do is:
 * 1) flush the D-cache if it's possible than an illegal alias
 *    has been created
 * 2) flush the I-cache if this is pre-cheetah and we did a write
 */
void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
			 unsigned long uaddr, void *kaddr,
			 unsigned long len, int write)
{
	BUG_ON(len > PAGE_SIZE);

	if (tlb_type == hypervisor)
		return;

	preempt_disable();

#ifdef DCACHE_ALIASING_POSSIBLE
	/* If bit 13 of the kernel address we used to access the
	 * user page is the same as the virtual address that page
	 * is mapped to in the user's address space, we can skip the
	 * D-cache flush.
	 */
	if ((uaddr ^ (unsigned long) kaddr) & (1UL << 13)) {
		unsigned long start = __pa(kaddr);
		unsigned long end = start + len;
		unsigned long dcache_line_size;

		dcache_line_size = local_cpu_data().dcache_line_size;

		if (tlb_type == spitfire) {
			for (; start < end; start += dcache_line_size)
				spitfire_put_dcache_tag(start & 0x3fe0, 0x0);
		} else {
			start &= ~(dcache_line_size - 1);
			for (; start < end; start += dcache_line_size)
				__asm__ __volatile__(
					"stxa %%g0, [%0] %1\n\t"
					"membar #Sync"
					: /* no outputs */
					: "r" (start),
					"i" (ASI_DCACHE_INVALIDATE));
		}
	}
#endif
	if (write && tlb_type == spitfire) {
		unsigned long start = (unsigned long) kaddr;
		unsigned long end = start + len;
		unsigned long icache_line_size;

		icache_line_size = local_cpu_data().icache_line_size;

		for (; start < end; start += icache_line_size)
			flushi(start);
	}

	preempt_enable();
}
EXPORT_SYMBOL_GPL(flush_ptrace_access);

static int get_from_target(struct task_struct *target, unsigned long uaddr,
			   void *kbuf, int len)
{
	if (target == current) {
		if (copy_from_user(kbuf, (void __user *) uaddr, len))
			return -EFAULT;
	} else {
		int len2 = access_process_vm(target, uaddr, kbuf, len,
				FOLL_FORCE);
		if (len2 != len)
			return -EFAULT;
	}
	return 0;
}

static int set_to_target(struct task_struct *target, unsigned long uaddr,
			 void *kbuf, int len)
{
	if (target == current) {
		if (copy_to_user((void __user *) uaddr, kbuf, len))
			return -EFAULT;
	} else {
		int len2 = access_process_vm(target, uaddr, kbuf, len,
				FOLL_FORCE | FOLL_WRITE);
		if (len2 != len)
			return -EFAULT;
	}
	return 0;
}

static int regwindow64_get(struct task_struct *target,
			   const struct pt_regs *regs,
			   struct reg_window *wbuf)
{
	unsigned long rw_addr = regs->u_regs[UREG_I6];

	if (!test_thread_64bit_stack(rw_addr)) {
		struct reg_window32 win32;
		int i;

		if (get_from_target(target, rw_addr, &win32, sizeof(win32)))
			return -EFAULT;
		for (i = 0; i < 8; i++)
			wbuf->locals[i] = win32.locals[i];
		for (i = 0; i < 8; i++)
			wbuf->ins[i] = win32.ins[i];
	} else {
		rw_addr += STACK_BIAS;
		if (get_from_target(target, rw_addr, wbuf, sizeof(*wbuf)))
			return -EFAULT;
	}

	return 0;
}

static int regwindow64_set(struct task_struct *target,
			   const struct pt_regs *regs,
			   struct reg_window *wbuf)
{
	unsigned long rw_addr = regs->u_regs[UREG_I6];

	if (!test_thread_64bit_stack(rw_addr)) {
		struct reg_window32 win32;
		int i;

		for (i = 0; i < 8; i++)
			win32.locals[i] = wbuf->locals[i];
		for (i = 0; i < 8; i++)
			win32.ins[i] = wbuf->ins[i];

		if (set_to_target(target, rw_addr, &win32, sizeof(win32)))
			return -EFAULT;
	} else {
		rw_addr += STACK_BIAS;
		if (set_to_target(target, rw_addr, wbuf, sizeof(*wbuf)))
			return -EFAULT;
	}

	return 0;
}

enum sparc_regset {
	REGSET_GENERAL,
	REGSET_FP,
};

static int genregs64_get(struct task_struct *target,
			 const struct user_regset *regset,
			 struct membuf to)
{
	const struct pt_regs *regs = task_pt_regs(target);
	struct reg_window window;

	if (target == current)
		flushw_user();

	membuf_write(&to, regs->u_regs, 16 * sizeof(u64));
	if (!to.left)
		return 0;
	if (regwindow64_get(target, regs, &window))
		return -EFAULT;
	membuf_write(&to, &window, 16 * sizeof(u64));
	/* TSTATE, TPC, TNPC */
	membuf_write(&to, &regs->tstate, 3 * sizeof(u64));
	return membuf_store(&to, (u64)regs->y);
}

static int genregs64_set(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 const void *kbuf, const void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	int ret;

	if (target == current)
		flushw_user();

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 regs->u_regs,
				 0, 16 * sizeof(u64));
	if (!ret && count && pos < (32 * sizeof(u64))) {
		struct reg_window window;

		if (regwindow64_get(target, regs, &window))
			return -EFAULT;

		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &window,
					 16 * sizeof(u64),
					 32 * sizeof(u64));

		if (!ret &&
		    regwindow64_set(target, regs, &window))
			return -EFAULT;
	}

	if (!ret && count > 0) {
		unsigned long tstate;

		/* TSTATE */
		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &tstate,
					 32 * sizeof(u64),
					 33 * sizeof(u64));
		if (!ret) {
			/* Only the condition codes and the "in syscall"
			 * state can be modified in the %tstate register.
			 */
			tstate &= (TSTATE_ICC | TSTATE_XCC | TSTATE_SYSCALL);
			regs->tstate &= ~(TSTATE_ICC | TSTATE_XCC | TSTATE_SYSCALL);
			regs->tstate |= tstate;
		}
	}

	if (!ret) {
		/* TPC, TNPC */
		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &regs->tpc,
					 33 * sizeof(u64),
					 35 * sizeof(u64));
	}

	if (!ret) {
		unsigned long y = regs->y;

		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &y,
					 35 * sizeof(u64),
					 36 * sizeof(u64));
		if (!ret)
			regs->y = y;
	}

	if (!ret)
		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
						36 * sizeof(u64), -1);

	return ret;
}

static int fpregs64_get(struct task_struct *target,
			const struct user_regset *regset,
			struct membuf to)
{
	struct thread_info *t = task_thread_info(target);
	unsigned long fprs;

	if (target == current)
		save_and_clear_fpu();

	fprs = t->fpsaved[0];

	if (fprs & FPRS_DL)
		membuf_write(&to, t->fpregs, 16 * sizeof(u64));
	else
		membuf_zero(&to, 16 * sizeof(u64));

	if (fprs & FPRS_DU)
		membuf_write(&to, t->fpregs + 16, 16 * sizeof(u64));
	else
		membuf_zero(&to, 16 * sizeof(u64));
	if (fprs & FPRS_FEF) {
		membuf_store(&to, t->xfsr[0]);
		membuf_store(&to, t->gsr[0]);
	} else {
		membuf_zero(&to, 2 * sizeof(u64));
	}
	return membuf_store(&to, fprs);
}

static int fpregs64_set(struct task_struct *target,
			const struct user_regset *regset,
			unsigned int pos, unsigned int count,
			const void *kbuf, const void __user *ubuf)
{
	unsigned long *fpregs = task_thread_info(target)->fpregs;
	unsigned long fprs;
	int ret;

	if (target == current)
		save_and_clear_fpu();

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 fpregs,
				 0, 32 * sizeof(u64));
	if (!ret)
		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 task_thread_info(target)->xfsr,
					 32 * sizeof(u64),
					 33 * sizeof(u64));
	if (!ret)
		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 task_thread_info(target)->gsr,
					 33 * sizeof(u64),
					 34 * sizeof(u64));

	fprs = task_thread_info(target)->fpsaved[0];
	if (!ret && count > 0) {
		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &fprs,
					 34 * sizeof(u64),
					 35 * sizeof(u64));
	}

	fprs |= (FPRS_FEF | FPRS_DL | FPRS_DU);
	task_thread_info(target)->fpsaved[0] = fprs;

	if (!ret)
		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
						35 * sizeof(u64), -1);
	return ret;
}

static const struct user_regset sparc64_regsets[] = {
	/* Format is:
	 * 	G0 --> G7
	 *	O0 --> O7
	 *	L0 --> L7
	 *	I0 --> I7
	 *	TSTATE, TPC, TNPC, Y
	 */
	[REGSET_GENERAL] = {
		.core_note_type = NT_PRSTATUS,
		.n = 36,
		.size = sizeof(u64), .align = sizeof(u64),
		.regset_get = genregs64_get, .set = genregs64_set
	},
	/* Format is:
	 *	F0 --> F63
	 *	FSR
	 *	GSR
	 *	FPRS
	 */
	[REGSET_FP] = {
		.core_note_type = NT_PRFPREG,
		.n = 35,
		.size = sizeof(u64), .align = sizeof(u64),
		.regset_get = fpregs64_get, .set = fpregs64_set
	},
};

static int getregs64_get(struct task_struct *target,
			 const struct user_regset *regset,
			 struct membuf to)
{
	const struct pt_regs *regs = task_pt_regs(target);

	if (target == current)
		flushw_user();

	membuf_write(&to, regs->u_regs + 1, 15 * sizeof(u64));
	membuf_store(&to, (u64)0);
	membuf_write(&to, &regs->tstate, 3 * sizeof(u64));
	return membuf_store(&to, (u64)regs->y);
}

static int setregs64_set(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 const void *kbuf, const void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	unsigned long y = regs->y;
	unsigned long tstate;
	int ret;

	if (target == current)
		flushw_user();

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 regs->u_regs + 1,
				 0 * sizeof(u64),
				 15 * sizeof(u64));
	if (ret)
		return ret;
	ret =user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
				 15 * sizeof(u64), 16 * sizeof(u64));
	if (ret)
		return ret;
	/* TSTATE */
	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &tstate,
				 16 * sizeof(u64),
				 17 * sizeof(u64));
	if (ret)
		return ret;
	/* Only the condition codes and the "in syscall"
	 * state can be modified in the %tstate register.
	 */
	tstate &= (TSTATE_ICC | TSTATE_XCC | TSTATE_SYSCALL);
	regs->tstate &= ~(TSTATE_ICC | TSTATE_XCC | TSTATE_SYSCALL);
	regs->tstate |= tstate;

	/* TPC, TNPC */
	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &regs->tpc,
				 17 * sizeof(u64),
				 19 * sizeof(u64));
	if (ret)
		return ret;
	/* Y */
	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 &y,
				 19 * sizeof(u64),
				 20 * sizeof(u64));
	if (!ret)
		regs->y = y;
	return ret;
}

static const struct user_regset ptrace64_regsets[] = {
	/* Format is:
	 *      G1 --> G7
	 *      O0 --> O7
	 *	0
	 *      TSTATE, TPC, TNPC, Y
	 */
	[REGSET_GENERAL] = {
		.n = 20, .size = sizeof(u64),
		.regset_get = getregs64_get, .set = setregs64_set,
	},
};

static const struct user_regset_view ptrace64_view = {
	.regsets = ptrace64_regsets, .n = ARRAY_SIZE(ptrace64_regsets)
};

static const struct user_regset_view user_sparc64_view = {
	.name = "sparc64", .e_machine = EM_SPARCV9,
	.regsets = sparc64_regsets, .n = ARRAY_SIZE(sparc64_regsets)
};

#ifdef CONFIG_COMPAT
static int genregs32_get(struct task_struct *target,
			 const struct user_regset *regset,
			 struct membuf to)
{
	const struct pt_regs *regs = task_pt_regs(target);
	u32 uregs[16];
	int i;

	if (target == current)
		flushw_user();

	for (i = 0; i < 16; i++)
		membuf_store(&to, (u32)regs->u_regs[i]);
	if (!to.left)
		return 0;
	if (get_from_target(target, regs->u_regs[UREG_I6],
			    uregs, sizeof(uregs)))
		return -EFAULT;
	membuf_write(&to, uregs, 16 * sizeof(u32));
	membuf_store(&to, (u32)tstate_to_psr(regs->tstate));
	membuf_store(&to, (u32)(regs->tpc));
	membuf_store(&to, (u32)(regs->tnpc));
	membuf_store(&to, (u32)(regs->y));
	return membuf_zero(&to, 2 * sizeof(u32));
}

static int genregs32_set(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 const void *kbuf, const void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	compat_ulong_t __user *reg_window;
	const compat_ulong_t *k = kbuf;
	const compat_ulong_t __user *u = ubuf;
	compat_ulong_t reg;

	if (target == current)
		flushw_user();

	pos /= sizeof(reg);
	count /= sizeof(reg);

	if (kbuf) {
		for (; count > 0 && pos < 16; count--)
			regs->u_regs[pos++] = *k++;

		reg_window = (compat_ulong_t __user *) regs->u_regs[UREG_I6];
		reg_window -= 16;
		if (target == current) {
			for (; count > 0 && pos < 32; count--) {
				if (put_user(*k++, &reg_window[pos++]))
					return -EFAULT;
			}
		} else {
			for (; count > 0 && pos < 32; count--) {
				if (access_process_vm(target,
						      (unsigned long)
						      &reg_window[pos],
						      (void *) k,
						      sizeof(*k),
						      FOLL_FORCE | FOLL_WRITE)
				    != sizeof(*k))
					return -EFAULT;
				k++;
				pos++;
			}
		}
	} else {
		for (; count > 0 && pos < 16; count--) {
			if (get_user(reg, u++))
				return -EFAULT;
			regs->u_regs[pos++] = reg;
		}

		reg_window = (compat_ulong_t __user *) regs->u_regs[UREG_I6];
		reg_window -= 16;
		if (target == current) {
			for (; count > 0 && pos < 32; count--) {
				if (get_user(reg, u++) ||
				    put_user(reg, &reg_window[pos++]))
					return -EFAULT;
			}
		} else {
			for (; count > 0 && pos < 32; count--) {
				if (get_user(reg, u++))
					return -EFAULT;
				if (access_process_vm(target,
						      (unsigned long)
						      &reg_window[pos],
						      &reg, sizeof(reg),
						      FOLL_FORCE | FOLL_WRITE)
				    != sizeof(reg))
					return -EFAULT;
				pos++;
				u++;
			}
		}
	}
	while (count > 0) {
		unsigned long tstate;

		if (kbuf)
			reg = *k++;
		else if (get_user(reg, u++))
			return -EFAULT;

		switch (pos) {
		case 32: /* PSR */
			tstate = regs->tstate;
			tstate &= ~(TSTATE_ICC | TSTATE_XCC | TSTATE_SYSCALL);
			tstate |= psr_to_tstate_icc(reg);
			if (reg & PSR_SYSCALL)
				tstate |= TSTATE_SYSCALL;
			regs->tstate = tstate;
			break;
		case 33: /* PC */
			regs->tpc = reg;
			break;
		case 34: /* NPC */
			regs->tnpc = reg;
			break;
		case 35: /* Y */
			regs->y = reg;
			break;
		case 36: /* WIM */
		case 37: /* TBR */
			break;
		default:
			goto finish;
		}

		pos++;
		count--;
	}
finish:
	pos *= sizeof(reg);
	count *= sizeof(reg);

	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
					 38 * sizeof(reg), -1);
}

static int fpregs32_get(struct task_struct *target,
			const struct user_regset *regset,
			struct membuf to)
{
	struct thread_info *t = task_thread_info(target);
	bool enabled;

	if (target == current)
		save_and_clear_fpu();

	enabled = t->fpsaved[0] & FPRS_FEF;

	membuf_write(&to, t->fpregs, 32 * sizeof(u32));
	membuf_zero(&to, sizeof(u32));
	if (enabled)
		membuf_store(&to, (u32)t->xfsr[0]);
	else
		membuf_zero(&to, sizeof(u32));
	membuf_store(&to, (u32)((enabled << 8) | (8 << 16)));
	return membuf_zero(&to, 64 * sizeof(u32));
}

static int fpregs32_set(struct task_struct *target,
			const struct user_regset *regset,
			unsigned int pos, unsigned int count,
			const void *kbuf, const void __user *ubuf)
{
	unsigned long *fpregs = task_thread_info(target)->fpregs;
	unsigned long fprs;
	int ret;

	if (target == current)
		save_and_clear_fpu();

	fprs = task_thread_info(target)->fpsaved[0];

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 fpregs,
				 0, 32 * sizeof(u32));
	if (!ret)
		user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
					  32 * sizeof(u32),
					  33 * sizeof(u32));
	if (!ret && count > 0) {
		compat_ulong_t fsr;
		unsigned long val;

		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &fsr,
					 33 * sizeof(u32),
					 34 * sizeof(u32));
		if (!ret) {
			val = task_thread_info(target)->xfsr[0];
			val &= 0xffffffff00000000UL;
			val |= fsr;
			task_thread_info(target)->xfsr[0] = val;
		}
	}

	fprs |= (FPRS_FEF | FPRS_DL);
	task_thread_info(target)->fpsaved[0] = fprs;

	if (!ret)
		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
						34 * sizeof(u32), -1);
	return ret;
}

static const struct user_regset sparc32_regsets[] = {
	/* Format is:
	 * 	G0 --> G7
	 *	O0 --> O7
	 *	L0 --> L7
	 *	I0 --> I7
	 *	PSR, PC, nPC, Y, WIM, TBR
	 */
	[REGSET_GENERAL] = {
		.core_note_type = NT_PRSTATUS,
		.n = 38,
		.size = sizeof(u32), .align = sizeof(u32),
		.regset_get = genregs32_get, .set = genregs32_set
	},
	/* Format is:
	 *	F0 --> F31
	 *	empty 32-bit word
	 *	FSR (32--bit word)
	 *	FPU QUEUE COUNT (8-bit char)
	 *	FPU QUEUE ENTRYSIZE (8-bit char)
	 *	FPU ENABLED (8-bit char)
	 *	empty 8-bit char
	 *	FPU QUEUE (64 32-bit ints)
	 */
	[REGSET_FP] = {
		.core_note_type = NT_PRFPREG,
		.n = 99,
		.size = sizeof(u32), .align = sizeof(u32),
		.regset_get = fpregs32_get, .set = fpregs32_set
	},
};

static int getregs_get(struct task_struct *target,
			 const struct user_regset *regset,
			 struct membuf to)
{
	const struct pt_regs *regs = task_pt_regs(target);
	int i;

	if (target == current)
		flushw_user();

	membuf_store(&to, (u32)tstate_to_psr(regs->tstate));
	membuf_store(&to, (u32)(regs->tpc));
	membuf_store(&to, (u32)(regs->tnpc));
	membuf_store(&to, (u32)(regs->y));
	for (i = 1; i < 16; i++)
		membuf_store(&to, (u32)regs->u_regs[i]);
	return to.left;
}

static int setregs_set(struct task_struct *target,
			 const struct user_regset *regset,
			 unsigned int pos, unsigned int count,
			 const void *kbuf, const void __user *ubuf)
{
	struct pt_regs *regs = task_pt_regs(target);
	unsigned long tstate;
	u32 uregs[19];
	int i, ret;

	if (target == current)
		flushw_user();

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 uregs,
				 0, 19 * sizeof(u32));
	if (ret)
		return ret;

	tstate = regs->tstate;
	tstate &= ~(TSTATE_ICC | TSTATE_XCC | TSTATE_SYSCALL);
	tstate |= psr_to_tstate_icc(uregs[0]);
	if (uregs[0] & PSR_SYSCALL)
		tstate |= TSTATE_SYSCALL;
	regs->tstate = tstate;
	regs->tpc = uregs[1];
	regs->tnpc = uregs[2];
	regs->y = uregs[3];

	for (i = 1; i < 15; i++)
		regs->u_regs[i] = uregs[3 + i];
	return 0;
}

static int getfpregs_get(struct task_struct *target,
			const struct user_regset *regset,
			struct membuf to)
{
	struct thread_info *t = task_thread_info(target);

	if (target == current)
		save_and_clear_fpu();

	membuf_write(&to, t->fpregs, 32 * sizeof(u32));
	if (t->fpsaved[0] & FPRS_FEF)
		membuf_store(&to, (u32)t->xfsr[0]);
	else
		membuf_zero(&to, sizeof(u32));
	return membuf_zero(&to, 35 * sizeof(u32));
}

static int setfpregs_set(struct task_struct *target,
			const struct user_regset *regset,
			unsigned int pos, unsigned int count,
			const void *kbuf, const void __user *ubuf)
{
	unsigned long *fpregs = task_thread_info(target)->fpregs;
	unsigned long fprs;
	int ret;

	if (target == current)
		save_and_clear_fpu();

	fprs = task_thread_info(target)->fpsaved[0];

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
				 fpregs,
				 0, 32 * sizeof(u32));
	if (!ret) {
		compat_ulong_t fsr;
		unsigned long val;

		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
					 &fsr,
					 32 * sizeof(u32),
					 33 * sizeof(u32));
		if (!ret) {
			val = task_thread_info(target)->xfsr[0];
			val &= 0xffffffff00000000UL;
			val |= fsr;
			task_thread_info(target)->xfsr[0] = val;
		}
	}

	fprs |= (FPRS_FEF | FPRS_DL);
	task_thread_info(target)->fpsaved[0] = fprs;
	return ret;
}

static const struct user_regset ptrace32_regsets[] = {
	[REGSET_GENERAL] = {
		.n = 19, .size = sizeof(u32),
		.regset_get = getregs_get, .set = setregs_set,
	},
	[REGSET_FP] = {
		.n = 68, .size = sizeof(u32),
		.regset_get = getfpregs_get, .set = setfpregs_set,
	},
};

static const struct user_regset_view ptrace32_view = {
	.regsets = ptrace32_regsets, .n = ARRAY_SIZE(ptrace32_regsets)
};

static const struct user_regset_view user_sparc32_view = {
	.name = "sparc", .e_machine = EM_SPARC,
	.regsets = sparc32_regsets, .n = ARRAY_SIZE(sparc32_regsets)
};
#endif /* CONFIG_COMPAT */

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
#ifdef CONFIG_COMPAT
	if (test_tsk_thread_flag(task, TIF_32BIT))
		return &user_sparc32_view;
#endif
	return &user_sparc64_view;
}

#ifdef CONFIG_COMPAT
struct compat_fps {
	unsigned int regs[32];
	unsigned int fsr;
	unsigned int flags;
	unsigned int extra;
	unsigned int fpqd;
	struct compat_fq {
		unsigned int insnaddr;
		unsigned int insn;
	} fpq[16];
};

long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
			compat_ulong_t caddr, compat_ulong_t cdata)
{
	compat_ulong_t caddr2 = task_pt_regs(current)->u_regs[UREG_I4];
	struct pt_regs32 __user *pregs;
	struct compat_fps __user *fps;
	unsigned long addr2 = caddr2;
	unsigned long addr = caddr;
	unsigned long data = cdata;
	int ret;

	pregs = (struct pt_regs32 __user *) addr;
	fps = (struct compat_fps __user *) addr;

	switch (request) {
	case PTRACE_PEEKUSR:
		ret = (addr != 0) ? -EIO : 0;
		break;

	case PTRACE_GETREGS:
		ret = copy_regset_to_user(child, &ptrace32_view,
					  REGSET_GENERAL, 0,
					  19 * sizeof(u32),
					  pregs);
		break;

	case PTRACE_SETREGS:
		ret = copy_regset_from_user(child, &ptrace32_view,
					  REGSET_GENERAL, 0,
					  19 * sizeof(u32),
					  pregs);
		break;

	case PTRACE_GETFPREGS:
		ret = copy_regset_to_user(child, &ptrace32_view,
					  REGSET_FP, 0,
					  68 * sizeof(u32),
					  fps);
		break;

	case PTRACE_SETFPREGS:
		ret = copy_regset_from_user(child, &ptrace32_view,
					  REGSET_FP, 0,
					  33 * sizeof(u32),
					  fps);
		break;

	case PTRACE_READTEXT:
	case PTRACE_READDATA:
		ret = ptrace_readdata(child, addr,
				      (char __user *)addr2, data);
		if (ret == data)
			ret = 0;
		else if (ret >= 0)
			ret = -EIO;
		break;

	case PTRACE_WRITETEXT:
	case PTRACE_WRITEDATA:
		ret = ptrace_writedata(child, (char __user *) addr2,
				       addr, data);
		if (ret == data)
			ret = 0;
		else if (ret >= 0)
			ret = -EIO;
		break;

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

	return ret;
}
#endif /* CONFIG_COMPAT */

struct fps {
	unsigned int regs[64];
	unsigned long fsr;
};

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	const struct user_regset_view *view = task_user_regset_view(current);
	unsigned long addr2 = task_pt_regs(current)->u_regs[UREG_I4];
	struct pt_regs __user *pregs;
	struct fps __user *fps;
	void __user *addr2p;
	int ret;

	pregs = (struct pt_regs __user *) addr;
	fps = (struct fps __user *) addr;
	addr2p = (void __user *) addr2;

	switch (request) {
	case PTRACE_PEEKUSR:
		ret = (addr != 0) ? -EIO : 0;
		break;

	case PTRACE_GETREGS64:
		ret = copy_regset_to_user(child, &ptrace64_view,
					  REGSET_GENERAL, 0,
					  19 * sizeof(u64),
					  pregs);
		break;

	case PTRACE_SETREGS64:
		ret = copy_regset_from_user(child, &ptrace64_view,
					  REGSET_GENERAL, 0,
					  19 * sizeof(u64),
					  pregs);
		break;

	case PTRACE_GETFPREGS64:
		ret = copy_regset_to_user(child, view, REGSET_FP,
					  0 * sizeof(u64),
					  33 * sizeof(u64),
					  fps);
		break;

	case PTRACE_SETFPREGS64:
		ret = copy_regset_from_user(child, view, REGSET_FP,
					  0 * sizeof(u64),
					  33 * sizeof(u64),
					  fps);
		break;

	case PTRACE_READTEXT:
	case PTRACE_READDATA:
		ret = ptrace_readdata(child, addr, addr2p, data);
		if (ret == data)
			ret = 0;
		else if (ret >= 0)
			ret = -EIO;
		break;

	case PTRACE_WRITETEXT:
	case PTRACE_WRITEDATA:
		ret = ptrace_writedata(child, addr2p, addr, data);
		if (ret == data)
			ret = 0;
		else if (ret >= 0)
			ret = -EIO;
		break;

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

	return ret;
}

asmlinkage int syscall_trace_enter(struct pt_regs *regs)
{
	int ret = 0;

	/* do the secure computing check first */
	secure_computing_strict(regs->u_regs[UREG_G1]);

	if (test_thread_flag(TIF_NOHZ))
		user_exit();

	if (test_thread_flag(TIF_SYSCALL_TRACE))
		ret = tracehook_report_syscall_entry(regs);

	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
		trace_sys_enter(regs, regs->u_regs[UREG_G1]);

	audit_syscall_entry(regs->u_regs[UREG_G1], regs->u_regs[UREG_I0],
			    regs->u_regs[UREG_I1], regs->u_regs[UREG_I2],
			    regs->u_regs[UREG_I3]);

	return ret;
}

asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
	if (test_thread_flag(TIF_NOHZ))
		user_exit();

	audit_syscall_exit(regs);

	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
		trace_sys_exit(regs, regs->u_regs[UREG_I0]);

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

	if (test_thread_flag(TIF_NOHZ))
		user_enter();
}

/**
 * regs_query_register_offset() - query register offset from its name
 * @name:	the name of a register
 *
 * regs_query_register_offset() returns the offset of a register in struct
 * pt_regs from its name. If the name is invalid, this returns -EINVAL;
 */
int regs_query_register_offset(const char *name)
{
	const struct pt_regs_offset *roff;

	for (roff = regoffset_table; roff->name != NULL; roff++)
		if (!strcmp(roff->name, name))
			return roff->offset;
	return -EINVAL;
}

/**
 * regs_within_kernel_stack() - check the address in the stack
 * @regs:	pt_regs which contains kernel stack pointer.
 * @addr:	address which is checked.
 *
 * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
 * If @addr is within the kernel stack, it returns true. If not, returns false.
 */
static inline int regs_within_kernel_stack(struct pt_regs *regs,
					   unsigned long addr)
{
	unsigned long ksp = kernel_stack_pointer(regs) + STACK_BIAS;
	return ((addr & ~(THREAD_SIZE - 1))  ==
		(ksp & ~(THREAD_SIZE - 1)));
}

/**
 * regs_get_kernel_stack_nth() - get Nth entry of the stack
 * @regs:	pt_regs which contains kernel stack pointer.
 * @n:		stack entry number.
 *
 * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
 * is specified by @regs. If the @n th entry is NOT in the kernel stack,
 * this returns 0.
 */
unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
{
	unsigned long ksp = kernel_stack_pointer(regs) + STACK_BIAS;
	unsigned long *addr = (unsigned long *)ksp;
	addr += n;
	if (regs_within_kernel_stack(regs, (unsigned long)addr))
		return *addr;
	else
		return 0;
}