Fixed MTP to work with TWRP

arch/arm/kernel/ptrace.c

@@ -0,0 +1,977 @@
+/*
+ *  linux/arch/arm/kernel/ptrace.c
+ *
+ *  By Ross Biro 1/23/92
+ * edited by Linus Torvalds
+ * ARM modifications Copyright (C) 2000 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/elf.h>
+#include <linux/smp.h>
+#include <linux/ptrace.h>
+#include <linux/user.h>
+#include <linux/security.h>
+#include <linux/init.h>
+#include <linux/signal.h>
+#include <linux/uaccess.h>
+#include <linux/perf_event.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/regset.h>
+#include <linux/audit.h>
+#include <linux/tracehook.h>
+#include <linux/unistd.h>
+
+#include <asm/pgtable.h>
+#include <asm/traps.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
+#define REG_PC	15
+#define REG_PSR	16
+/*
+ * does not yet catch signals sent when the child dies.
+ * in exit.c or in signal.c.
+ */
+
+#if 0
+/*
+ * Breakpoint SWI instruction: SWI &9F0001
+ */
+#define BREAKINST_ARM	0xef9f0001
+#define BREAKINST_THUMB	0xdf00		/* fill this in later */
+#else
+/*
+ * New breakpoints - use an undefined instruction.  The ARM architecture
+ * reference manual guarantees that the following instruction space
+ * will produce an undefined instruction exception on all CPUs:
+ *
+ *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
+ *  Thumb: 1101 1110 xxxx xxxx
+ */
+#define BREAKINST_ARM	0xe7f001f0
+#define BREAKINST_THUMB	0xde01
+#endif
+
+struct pt_regs_offset {
+	const char *name;
+	int offset;
+};
+
+#define REG_OFFSET_NAME(r) \
+	{.name = #r, .offset = offsetof(struct pt_regs, ARM_##r)}
+#define REG_OFFSET_END {.name = NULL, .offset = 0}
+
+static const struct pt_regs_offset regoffset_table[] = {
+	REG_OFFSET_NAME(r0),
+	REG_OFFSET_NAME(r1),
+	REG_OFFSET_NAME(r2),
+	REG_OFFSET_NAME(r3),
+	REG_OFFSET_NAME(r4),
+	REG_OFFSET_NAME(r5),
+	REG_OFFSET_NAME(r6),
+	REG_OFFSET_NAME(r7),
+	REG_OFFSET_NAME(r8),
+	REG_OFFSET_NAME(r9),
+	REG_OFFSET_NAME(r10),
+	REG_OFFSET_NAME(fp),
+	REG_OFFSET_NAME(ip),
+	REG_OFFSET_NAME(sp),
+	REG_OFFSET_NAME(lr),
+	REG_OFFSET_NAME(pc),
+	REG_OFFSET_NAME(cpsr),
+	REG_OFFSET_NAME(ORIG_r0),
+	REG_OFFSET_END,
+};
+
+/**
+ * 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_query_register_name() - query register name from its offset
+ * @offset:	the offset of a register in struct pt_regs.
+ *
+ * regs_query_register_name() returns the name of a register from its
+ * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
+ */
+const char *regs_query_register_name(unsigned int offset)
+{
+	const struct pt_regs_offset *roff;
+	for (roff = regoffset_table; roff->name != NULL; roff++)
+		if (roff->offset == offset)
+			return roff->name;
+	return NULL;
+}
+
+/**
+ * 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.
+ */
+bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
+{
+	return ((addr & ~(THREAD_SIZE - 1))  ==
+		(kernel_stack_pointer(regs) & ~(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 *addr = (unsigned long *)kernel_stack_pointer(regs);
+	addr += n;
+	if (regs_within_kernel_stack(regs, (unsigned long)addr))
+		return *addr;
+	else
+		return 0;
+}
+
+/*
+ * this routine will get a word off of the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline long get_user_reg(struct task_struct *task, int offset)
+{
+	return task_pt_regs(task)->uregs[offset];
+}
+
+/*
+ * this routine will put a word on the processes privileged stack.
+ * the offset is how far from the base addr as stored in the THREAD.
+ * this routine assumes that all the privileged stacks are in our
+ * data space.
+ */
+static inline int
+put_user_reg(struct task_struct *task, int offset, long data)
+{
+	struct pt_regs newregs, *regs = task_pt_regs(task);
+	int ret = -EINVAL;
+
+	newregs = *regs;
+	newregs.uregs[offset] = data;
+
+	if (valid_user_regs(&newregs)) {
+		regs->uregs[offset] = data;
+		ret = 0;
+	}
+
+	return ret;
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ */
+void ptrace_disable(struct task_struct *child)
+{
+	/* Nothing to do. */
+}
+
+/*
+ * Handle hitting a breakpoint.
+ */
+void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
+{
+	siginfo_t info;
+
+	info.si_signo = SIGTRAP;
+	info.si_errno = 0;
+	info.si_code  = TRAP_BRKPT;
+	info.si_addr  = (void __user *)instruction_pointer(regs);
+
+	force_sig_info(SIGTRAP, &info, tsk);
+}
+
+static int break_trap(struct pt_regs *regs, unsigned int instr)
+{
+	ptrace_break(current, regs);
+	return 0;
+}
+
+static struct undef_hook arm_break_hook = {
+	.instr_mask	= 0x0fffffff,
+	.instr_val	= 0x07f001f0,
+	.cpsr_mask	= PSR_T_BIT,
+	.cpsr_val	= 0,
+	.fn		= break_trap,
+};
+
+static struct undef_hook thumb_break_hook = {
+	.instr_mask	= 0xffff,
+	.instr_val	= 0xde01,
+	.cpsr_mask	= PSR_T_BIT,
+	.cpsr_val	= PSR_T_BIT,
+	.fn		= break_trap,
+};
+
+static struct undef_hook thumb2_break_hook = {
+	.instr_mask	= 0xffffffff,
+	.instr_val	= 0xf7f0a000,
+	.cpsr_mask	= PSR_T_BIT,
+	.cpsr_val	= PSR_T_BIT,
+	.fn		= break_trap,
+};
+
+static int __init ptrace_break_init(void)
+{
+	register_undef_hook(&arm_break_hook);
+	register_undef_hook(&thumb_break_hook);
+	register_undef_hook(&thumb2_break_hook);
+	return 0;
+}
+
+core_initcall(ptrace_break_init);
+
+/*
+ * Read the word at offset "off" into the "struct user".  We
+ * actually access the pt_regs stored on the kernel stack.
+ */
+static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
+			    unsigned long __user *ret)
+{
+	unsigned long tmp;
+
+	if (off & 3)
+		return -EIO;
+
+	tmp = 0;
+	if (off == PT_TEXT_ADDR)
+		tmp = tsk->mm->start_code;
+	else if (off == PT_DATA_ADDR)
+		tmp = tsk->mm->start_data;
+	else if (off == PT_TEXT_END_ADDR)
+		tmp = tsk->mm->end_code;
+	else if (off < sizeof(struct pt_regs))
+		tmp = get_user_reg(tsk, off >> 2);
+	else if (off >= sizeof(struct user))
+		return -EIO;
+
+	return put_user(tmp, ret);
+}
+
+/*
+ * Write the word at offset "off" into "struct user".  We
+ * actually access the pt_regs stored on the kernel stack.
+ */
+static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
+			     unsigned long val)
+{
+	if (off & 3 || off >= sizeof(struct user))
+		return -EIO;
+
+	if (off >= sizeof(struct pt_regs))
+		return 0;
+
+	return put_user_reg(tsk, off >> 2, val);
+}
+
+#ifdef CONFIG_IWMMXT
+
+/*
+ * Get the child iWMMXt state.
+ */
+static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
+{
+	struct thread_info *thread = task_thread_info(tsk);
+
+	if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
+		return -ENODATA;
+	iwmmxt_task_disable(thread);  /* force it to ram */
+	return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
+		? -EFAULT : 0;
+}
+
+/*
+ * Set the child iWMMXt state.
+ */
+static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
+{
+	struct thread_info *thread = task_thread_info(tsk);
+
+	if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
+		return -EACCES;
+	iwmmxt_task_release(thread);  /* force a reload */
+	return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
+		? -EFAULT : 0;
+}
+
+#endif
+
+#ifdef CONFIG_CRUNCH
+/*
+ * Get the child Crunch state.
+ */
+static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
+{
+	struct thread_info *thread = task_thread_info(tsk);
+
+	crunch_task_disable(thread);  /* force it to ram */
+	return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
+		? -EFAULT : 0;
+}
+
+/*
+ * Set the child Crunch state.
+ */
+static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
+{
+	struct thread_info *thread = task_thread_info(tsk);
+
+	crunch_task_release(thread);  /* force a reload */
+	return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
+		? -EFAULT : 0;
+}
+#endif
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+/*
+ * Convert a virtual register number into an index for a thread_info
+ * breakpoint array. Breakpoints are identified using positive numbers
+ * whilst watchpoints are negative. The registers are laid out as pairs
+ * of (address, control), each pair mapping to a unique hw_breakpoint struct.
+ * Register 0 is reserved for describing resource information.
+ */
+static int ptrace_hbp_num_to_idx(long num)
+{
+	if (num < 0)
+		num = (ARM_MAX_BRP << 1) - num;
+	return (num - 1) >> 1;
+}
+
+/*
+ * Returns the virtual register number for the address of the
+ * breakpoint at index idx.
+ */
+static long ptrace_hbp_idx_to_num(int idx)
+{
+	long mid = ARM_MAX_BRP << 1;
+	long num = (idx << 1) + 1;
+	return num > mid ? mid - num : num;
+}
+
+/*
+ * Handle hitting a HW-breakpoint.
+ */
+static void ptrace_hbptriggered(struct perf_event *bp,
+				     struct perf_sample_data *data,
+				     struct pt_regs *regs)
+{
+	struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
+	long num;
+	int i;
+	siginfo_t info;
+
+	for (i = 0; i < ARM_MAX_HBP_SLOTS; ++i)
+		if (current->thread.debug.hbp[i] == bp)
+			break;
+
+	num = (i == ARM_MAX_HBP_SLOTS) ? 0 : ptrace_hbp_idx_to_num(i);
+
+	info.si_signo	= SIGTRAP;
+	info.si_errno	= (int)num;
+	info.si_code	= TRAP_HWBKPT;
+	info.si_addr	= (void __user *)(bkpt->trigger);
+
+	force_sig_info(SIGTRAP, &info, current);
+}
+
+/*
+ * Set ptrace breakpoint pointers to zero for this task.
+ * This is required in order to prevent child processes from unregistering
+ * breakpoints held by their parent.
+ */
+void clear_ptrace_hw_breakpoint(struct task_struct *tsk)
+{
+	memset(tsk->thread.debug.hbp, 0, sizeof(tsk->thread.debug.hbp));
+}
+
+/*
+ * Unregister breakpoints from this task and reset the pointers in
+ * the thread_struct.
+ */
+void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
+{
+	int i;
+	struct thread_struct *t = &tsk->thread;
+
+	for (i = 0; i < ARM_MAX_HBP_SLOTS; i++) {
+		if (t->debug.hbp[i]) {
+			unregister_hw_breakpoint(t->debug.hbp[i]);
+			t->debug.hbp[i] = NULL;
+		}
+	}
+}
+
+static u32 ptrace_get_hbp_resource_info(void)
+{
+	u8 num_brps, num_wrps, debug_arch, wp_len;
+	u32 reg = 0;
+
+	num_brps	= hw_breakpoint_slots(TYPE_INST);
+	num_wrps	= hw_breakpoint_slots(TYPE_DATA);
+	debug_arch	= arch_get_debug_arch();
+	wp_len		= arch_get_max_wp_len();
+
+	reg		|= debug_arch;
+	reg		<<= 8;
+	reg		|= wp_len;
+	reg		<<= 8;
+	reg		|= num_wrps;
+	reg		<<= 8;
+	reg		|= num_brps;
+
+	return reg;
+}
+
+static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
+{
+	struct perf_event_attr attr;
+
+	ptrace_breakpoint_init(&attr);
+
+	/* Initialise fields to sane defaults. */
+	attr.bp_addr	= 0;
+	attr.bp_len	= HW_BREAKPOINT_LEN_4;
+	attr.bp_type	= type;
+	attr.disabled	= 1;
+
+	return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
+					   tsk);
+}
+
+static int ptrace_gethbpregs(struct task_struct *tsk, long num,
+			     unsigned long  __user *data)
+{
+	u32 reg;
+	int idx, ret = 0;
+	struct perf_event *bp;
+	struct arch_hw_breakpoint_ctrl arch_ctrl;
+
+	if (num == 0) {
+		reg = ptrace_get_hbp_resource_info();
+	} else {
+		idx = ptrace_hbp_num_to_idx(num);
+		if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		bp = tsk->thread.debug.hbp[idx];
+		if (!bp) {
+			reg = 0;
+			goto put;
+		}
+
+		arch_ctrl = counter_arch_bp(bp)->ctrl;
+
+		/*
+		 * Fix up the len because we may have adjusted it
+		 * to compensate for an unaligned address.
+		 */
+		while (!(arch_ctrl.len & 0x1))
+			arch_ctrl.len >>= 1;
+
+		if (num & 0x1)
+			reg = bp->attr.bp_addr;
+		else
+			reg = encode_ctrl_reg(arch_ctrl);
+	}
+
+put:
+	if (put_user(reg, data))
+		ret = -EFAULT;
+
+out:
+	return ret;
+}
+
+static int ptrace_sethbpregs(struct task_struct *tsk, long num,
+			     unsigned long __user *data)
+{
+	int idx, gen_len, gen_type, implied_type, ret = 0;
+	u32 user_val;
+	struct perf_event *bp;
+	struct arch_hw_breakpoint_ctrl ctrl;
+	struct perf_event_attr attr;
+
+	if (num == 0)
+		goto out;
+	else if (num < 0)
+		implied_type = HW_BREAKPOINT_RW;
+	else
+		implied_type = HW_BREAKPOINT_X;
+
+	idx = ptrace_hbp_num_to_idx(num);
+	if (idx < 0 || idx >= ARM_MAX_HBP_SLOTS) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (get_user(user_val, data)) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	bp = tsk->thread.debug.hbp[idx];
+	if (!bp) {
+		bp = ptrace_hbp_create(tsk, implied_type);
+		if (IS_ERR(bp)) {
+			ret = PTR_ERR(bp);
+			goto out;
+		}
+		tsk->thread.debug.hbp[idx] = bp;
+	}
+
+	attr = bp->attr;
+
+	if (num & 0x1) {
+		/* Address */
+		attr.bp_addr	= user_val;
+	} else {
+		/* Control */
+		decode_ctrl_reg(user_val, &ctrl);
+		ret = arch_bp_generic_fields(ctrl, &gen_len, &gen_type);
+		if (ret)
+			goto out;
+
+		if ((gen_type & implied_type) != gen_type) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		attr.bp_len	= gen_len;
+		attr.bp_type	= gen_type;
+		attr.disabled	= !ctrl.enabled;
+	}
+
+	ret = modify_user_hw_breakpoint(bp, &attr);
+out:
+	return ret;
+}
+#endif
+
+/* regset get/set implementations */
+
+static int 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 = task_pt_regs(target);
+
+	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				   regs,
+				   0, sizeof(*regs));
+}
+
+static int 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 newregs;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &newregs,
+				 0, sizeof(newregs));
+	if (ret)
+		return ret;
+
+	if (!valid_user_regs(&newregs))
+		return -EINVAL;
+
+	*task_pt_regs(target) = newregs;
+	return 0;
+}
+
+static int fpa_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   void *kbuf, void __user *ubuf)
+{
+	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				   &task_thread_info(target)->fpstate,
+				   0, sizeof(struct user_fp));
+}
+
+static int fpa_set(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	struct thread_info *thread = task_thread_info(target);
+
+	thread->used_cp[1] = thread->used_cp[2] = 1;
+
+	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+		&thread->fpstate,
+		0, sizeof(struct user_fp));
+}
+
+#ifdef CONFIG_VFP
+/*
+ * VFP register get/set implementations.
+ *
+ * With respect to the kernel, struct user_fp is divided into three chunks:
+ * 16 or 32 real VFP registers (d0-d15 or d0-31)
+ *	These are transferred to/from the real registers in the task's
+ *	vfp_hard_struct.  The number of registers depends on the kernel
+ *	configuration.
+ *
+ * 16 or 0 fake VFP registers (d16-d31 or empty)
+ *	i.e., the user_vfp structure has space for 32 registers even if
+ *	the kernel doesn't have them all.
+ *
+ *	vfp_get() reads this chunk as zero where applicable
+ *	vfp_set() ignores this chunk
+ *
+ * 1 word for the FPSCR
+ *
+ * The bounds-checking logic built into user_regset_copyout and friends
+ * means that we can make a simple sequence of calls to map the relevant data
+ * to/from the specified slice of the user regset structure.
+ */
+static int vfp_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   void *kbuf, void __user *ubuf)
+{
+	int ret;
+	struct thread_info *thread = task_thread_info(target);
+	struct vfp_hard_struct const *vfp = &thread->vfpstate.hard;
+	const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
+	const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
+
+	vfp_sync_hwstate(thread);
+
+	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				  &vfp->fpregs,
+				  user_fpregs_offset,
+				  user_fpregs_offset + sizeof(vfp->fpregs));
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
+				       user_fpregs_offset + sizeof(vfp->fpregs),
+				       user_fpscr_offset);
+	if (ret)
+		return ret;
+
+	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+				   &vfp->fpscr,
+				   user_fpscr_offset,
+				   user_fpscr_offset + sizeof(vfp->fpscr));
+}
+
+/*
+ * For vfp_set() a read-modify-write is done on the VFP registers,
+ * in order to avoid writing back a half-modified set of registers on
+ * failure.
+ */
+static int vfp_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 thread_info *thread = task_thread_info(target);
+	struct vfp_hard_struct new_vfp;
+	const size_t user_fpregs_offset = offsetof(struct user_vfp, fpregs);
+	const size_t user_fpscr_offset = offsetof(struct user_vfp, fpscr);
+
+	vfp_sync_hwstate(thread);
+	new_vfp = thread->vfpstate.hard;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				  &new_vfp.fpregs,
+				  user_fpregs_offset,
+				  user_fpregs_offset + sizeof(new_vfp.fpregs));
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
+				user_fpregs_offset + sizeof(new_vfp.fpregs),
+				user_fpscr_offset);
+	if (ret)
+		return ret;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 &new_vfp.fpscr,
+				 user_fpscr_offset,
+				 user_fpscr_offset + sizeof(new_vfp.fpscr));
+	if (ret)
+		return ret;
+
+	vfp_flush_hwstate(thread);
+	thread->vfpstate.hard = new_vfp;
+
+	return 0;
+}
+#endif /* CONFIG_VFP */
+
+enum arm_regset {
+	REGSET_GPR,
+	REGSET_FPR,
+#ifdef CONFIG_VFP
+	REGSET_VFP,
+#endif
+};
+
+static const struct user_regset arm_regsets[] = {
+	[REGSET_GPR] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = ELF_NGREG,
+		.size = sizeof(u32),
+		.align = sizeof(u32),
+		.get = gpr_get,
+		.set = gpr_set
+	},
+	[REGSET_FPR] = {
+		/*
+		 * For the FPA regs in fpstate, the real fields are a mixture
+		 * of sizes, so pretend that the registers are word-sized:
+		 */
+		.core_note_type = NT_PRFPREG,
+		.n = sizeof(struct user_fp) / sizeof(u32),
+		.size = sizeof(u32),
+		.align = sizeof(u32),
+		.get = fpa_get,
+		.set = fpa_set
+	},
+#ifdef CONFIG_VFP
+	[REGSET_VFP] = {
+		/*
+		 * Pretend that the VFP regs are word-sized, since the FPSCR is
+		 * a single word dangling at the end of struct user_vfp:
+		 */
+		.core_note_type = NT_ARM_VFP,
+		.n = ARM_VFPREGS_SIZE / sizeof(u32),
+		.size = sizeof(u32),
+		.align = sizeof(u32),
+		.get = vfp_get,
+		.set = vfp_set
+	},
+#endif /* CONFIG_VFP */
+};
+
+static const struct user_regset_view user_arm_view = {
+	.name = "arm", .e_machine = ELF_ARCH, .ei_osabi = ELF_OSABI,
+	.regsets = arm_regsets, .n = ARRAY_SIZE(arm_regsets)
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &user_arm_view;
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	int ret;
+	unsigned long __user *datap = (unsigned long __user *) data;
+
+	switch (request) {
+		case PTRACE_PEEKUSR:
+			ret = ptrace_read_user(child, addr, datap);
+			break;
+
+		case PTRACE_POKEUSR:
+			ret = ptrace_write_user(child, addr, data);
+			break;
+
+		case PTRACE_GETREGS:
+			ret = copy_regset_to_user(child,
+						  &user_arm_view, REGSET_GPR,
+						  0, sizeof(struct pt_regs),
+						  datap);
+			break;
+
+		case PTRACE_SETREGS:
+			ret = copy_regset_from_user(child,
+						    &user_arm_view, REGSET_GPR,
+						    0, sizeof(struct pt_regs),
+						    datap);
+			break;
+
+		case PTRACE_GETFPREGS:
+			ret = copy_regset_to_user(child,
+						  &user_arm_view, REGSET_FPR,
+						  0, sizeof(union fp_state),
+						  datap);
+			break;
+
+		case PTRACE_SETFPREGS:
+			ret = copy_regset_from_user(child,
+						    &user_arm_view, REGSET_FPR,
+						    0, sizeof(union fp_state),
+						    datap);
+			break;
+
+#ifdef CONFIG_IWMMXT
+		case PTRACE_GETWMMXREGS:
+			ret = ptrace_getwmmxregs(child, datap);
+			break;
+
+		case PTRACE_SETWMMXREGS:
+			ret = ptrace_setwmmxregs(child, datap);
+			break;
+#endif
+
+		case PTRACE_GET_THREAD_AREA:
+			ret = put_user(task_thread_info(child)->tp_value[0],
+				       datap);
+			break;
+
+		case PTRACE_SET_SYSCALL:
+			task_thread_info(child)->syscall = data;
+			ret = 0;
+			break;
+
+#ifdef CONFIG_CRUNCH
+		case PTRACE_GETCRUNCHREGS:
+			ret = ptrace_getcrunchregs(child, datap);
+			break;
+
+		case PTRACE_SETCRUNCHREGS:
+			ret = ptrace_setcrunchregs(child, datap);
+			break;
+#endif
+
+#ifdef CONFIG_VFP
+		case PTRACE_GETVFPREGS:
+			ret = copy_regset_to_user(child,
+						  &user_arm_view, REGSET_VFP,
+						  0, ARM_VFPREGS_SIZE,
+						  datap);
+			break;
+
+		case PTRACE_SETVFPREGS:
+			ret = copy_regset_from_user(child,
+						    &user_arm_view, REGSET_VFP,
+						    0, ARM_VFPREGS_SIZE,
+						    datap);
+			break;
+#endif
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+		case PTRACE_GETHBPREGS:
+			ret = ptrace_gethbpregs(child, addr,
+						(unsigned long __user *)data);
+			break;
+		case PTRACE_SETHBPREGS:
+			ret = ptrace_sethbpregs(child, addr,
+						(unsigned long __user *)data);
+			break;
+#endif
+
+		default:
+			ret = ptrace_request(child, request, addr, data);
+			break;
+	}
+
+	return ret;
+}
+
+enum ptrace_syscall_dir {
+	PTRACE_SYSCALL_ENTER = 0,
+	PTRACE_SYSCALL_EXIT,
+};
+
+static void tracehook_report_syscall(struct pt_regs *regs,
+				    enum ptrace_syscall_dir dir)
+{
+	unsigned long ip;
+
+	/*
+	 * IP is used to denote syscall entry/exit:
+	 * IP = 0 -> entry, =1 -> exit
+	 */
+	ip = regs->ARM_ip;
+	regs->ARM_ip = dir;
+
+	if (dir == PTRACE_SYSCALL_EXIT)
+		tracehook_report_syscall_exit(regs, 0);
+	else if (tracehook_report_syscall_entry(regs))
+		current_thread_info()->syscall = -1;
+
+	regs->ARM_ip = ip;
+}
+
+asmlinkage int syscall_trace_enter(struct pt_regs *regs, int scno)
+{
+	current_thread_info()->syscall = scno;
+
+	/* Do the secure computing check first; failures should be fast. */
+#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER
+	if (secure_computing() == -1)
+		return -1;
+#else
+	/* XXX: remove this once OABI gets fixed */
+	secure_computing_strict(scno);
+#endif
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
+
+	scno = current_thread_info()->syscall;
+
+	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+		trace_sys_enter(regs, scno);
+
+	audit_syscall_entry(scno, regs->ARM_r0, regs->ARM_r1, regs->ARM_r2,
+			    regs->ARM_r3);
+
+	return scno;
+}
+
+asmlinkage void syscall_trace_exit(struct pt_regs *regs)
+{
+	/*
+	 * Audit the syscall before anything else, as a debugger may
+	 * come in and change the current registers.
+	 */
+	audit_syscall_exit(regs);
+
+	/*
+	 * Note that we haven't updated the ->syscall field for the
+	 * current thread. This isn't a problem because it will have
+	 * been set on syscall entry and there hasn't been an opportunity
+	 * for a PTRACE_SET_SYSCALL since then.
+	 */
+	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+		trace_sys_exit(regs, regs_return_value(regs));
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
+}