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bench_mysql.py

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  • ptrace.c 37.87 KiB
    /* By Ross Biro 1/23/92 */
    /*
     * Pentium III FXSR, SSE support
     *	Gareth Hughes <gareth@valinux.com>, May 2000
     */
    
    #include <linux/kernel.h>
    #include <linux/sched.h>
    #include <linux/mm.h>
    #include <linux/smp.h>
    #include <linux/errno.h>
    #include <linux/slab.h>
    #include <linux/ptrace.h>
    #include <linux/regset.h>
    #include <linux/tracehook.h>
    #include <linux/user.h>
    #include <linux/elf.h>
    #include <linux/security.h>
    #include <linux/audit.h>
    #include <linux/seccomp.h>
    #include <linux/signal.h>
    #include <linux/perf_event.h>
    #include <linux/hw_breakpoint.h>
    
    #include <asm/uaccess.h>
    #include <asm/pgtable.h>
    #include <asm/processor.h>
    #include <asm/i387.h>
    #include <asm/fpu-internal.h>
    #include <asm/debugreg.h>
    #include <asm/ldt.h>
    #include <asm/desc.h>
    #include <asm/prctl.h>
    #include <asm/proto.h>
    #include <asm/hw_breakpoint.h>
    #include <asm/traps.h>
    
    #include "tls.h"
    
    #define CREATE_TRACE_POINTS
    #include <trace/events/syscalls.h>
    
    enum x86_regset {
    	REGSET_GENERAL,
    	REGSET_FP,
    	REGSET_XFP,
    	REGSET_IOPERM64 = REGSET_XFP,
    	REGSET_XSTATE,
    	REGSET_TLS,
    	REGSET_IOPERM32,
    };
    
    struct pt_regs_offset {
    	const char *name;
    	int offset;
    };
    
    #define REG_OFFSET_NAME(r) {.name = #r, .offset = offsetof(struct pt_regs, r)}
    #define REG_OFFSET_END {.name = NULL, .offset = 0}
    
    static const struct pt_regs_offset regoffset_table[] = {
    #ifdef CONFIG_X86_64
    	REG_OFFSET_NAME(r15),
    	REG_OFFSET_NAME(r14),
    	REG_OFFSET_NAME(r13),
    	REG_OFFSET_NAME(r12),
    	REG_OFFSET_NAME(r11),
    	REG_OFFSET_NAME(r10),
    	REG_OFFSET_NAME(r9),
    	REG_OFFSET_NAME(r8),
    #endif
    	REG_OFFSET_NAME(bx),
    	REG_OFFSET_NAME(cx),
    	REG_OFFSET_NAME(dx),
    	REG_OFFSET_NAME(si),
    	REG_OFFSET_NAME(di),
    	REG_OFFSET_NAME(bp),
    	REG_OFFSET_NAME(ax),
    #ifdef CONFIG_X86_32
    	REG_OFFSET_NAME(ds),
    	REG_OFFSET_NAME(es),
    	REG_OFFSET_NAME(fs),
    	REG_OFFSET_NAME(gs),
    #endif
    	REG_OFFSET_NAME(orig_ax),
    	REG_OFFSET_NAME(ip),
    	REG_OFFSET_NAME(cs),
    	REG_OFFSET_NAME(flags),
    	REG_OFFSET_NAME(sp),
    	REG_OFFSET_NAME(ss),
    	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;
    }
    
    static const int arg_offs_table[] = {
    #ifdef CONFIG_X86_32
    	[0] = offsetof(struct pt_regs, ax),
    	[1] = offsetof(struct pt_regs, dx),
    	[2] = offsetof(struct pt_regs, cx)
    #else /* CONFIG_X86_64 */
    	[0] = offsetof(struct pt_regs, di),
    	[1] = offsetof(struct pt_regs, si),
    	[2] = offsetof(struct pt_regs, dx),
    	[3] = offsetof(struct pt_regs, cx),
    	[4] = offsetof(struct pt_regs, r8),
    	[5] = offsetof(struct pt_regs, r9)
    #endif
    };
    
    /*
     * does not yet catch signals sent when the child dies.
     * in exit.c or in signal.c.
     */
    
    /*
     * Determines which flags the user has access to [1 = access, 0 = no access].
     */
    #define FLAG_MASK_32		((unsigned long)			\
    				 (X86_EFLAGS_CF | X86_EFLAGS_PF |	\
    				  X86_EFLAGS_AF | X86_EFLAGS_ZF |	\
    				  X86_EFLAGS_SF | X86_EFLAGS_TF |	\
    				  X86_EFLAGS_DF | X86_EFLAGS_OF |	\
    				  X86_EFLAGS_RF | X86_EFLAGS_AC))
    
    /*
     * Determines whether a value may be installed in a segment register.
     */
    static inline bool invalid_selector(u16 value)
    {
    	return unlikely(value != 0 && (value & SEGMENT_RPL_MASK) != USER_RPL);
    }
    
    #ifdef CONFIG_X86_32
    
    #define FLAG_MASK		FLAG_MASK_32
    
    static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
    {
    	BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
    	return &regs->bx + (regno >> 2);
    }
    
    static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
    {
    	/*
    	 * Returning the value truncates it to 16 bits.
    	 */
    	unsigned int retval;
    	if (offset != offsetof(struct user_regs_struct, gs))
    		retval = *pt_regs_access(task_pt_regs(task), offset);
    	else {
    		if (task == current)
    			retval = get_user_gs(task_pt_regs(task));
    		else
    			retval = task_user_gs(task);
    	}
    	return retval;
    }
    
    static int set_segment_reg(struct task_struct *task,
    			   unsigned long offset, u16 value)
    {
    	/*
    	 * The value argument was already truncated to 16 bits.
    	 */
    	if (invalid_selector(value))
    		return -EIO;
    
    	/*
    	 * For %cs and %ss we cannot permit a null selector.
    	 * We can permit a bogus selector as long as it has USER_RPL.
    	 * Null selectors are fine for other segment registers, but
    	 * we will never get back to user mode with invalid %cs or %ss
    	 * and will take the trap in iret instead.  Much code relies
    	 * on user_mode() to distinguish a user trap frame (which can
    	 * safely use invalid selectors) from a kernel trap frame.
    	 */
    	switch (offset) {
    	case offsetof(struct user_regs_struct, cs):
    	case offsetof(struct user_regs_struct, ss):
    		if (unlikely(value == 0))
    			return -EIO;
    
    	default:
    		*pt_regs_access(task_pt_regs(task), offset) = value;
    		break;
    
    	case offsetof(struct user_regs_struct, gs):
    		if (task == current)
    			set_user_gs(task_pt_regs(task), value);
    		else
    			task_user_gs(task) = value;
    	}
    
    	return 0;
    }
    
    #else  /* CONFIG_X86_64 */
    
    #define FLAG_MASK		(FLAG_MASK_32 | X86_EFLAGS_NT)
    
    static unsigned long *pt_regs_access(struct pt_regs *regs, unsigned long offset)
    {
    	BUILD_BUG_ON(offsetof(struct pt_regs, r15) != 0);
    	return &regs->r15 + (offset / sizeof(regs->r15));
    }
    
    static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
    {
    	/*
    	 * Returning the value truncates it to 16 bits.
    	 */
    	unsigned int seg;
    
    	switch (offset) {
    	case offsetof(struct user_regs_struct, fs):
    		if (task == current) {
    			/* Older gas can't assemble movq %?s,%r?? */
    			asm("movl %%fs,%0" : "=r" (seg));
    			return seg;
    		}
    		return task->thread.fsindex;
    	case offsetof(struct user_regs_struct, gs):
    		if (task == current) {
    			asm("movl %%gs,%0" : "=r" (seg));
    			return seg;
    		}
    		return task->thread.gsindex;
    	case offsetof(struct user_regs_struct, ds):
    		if (task == current) {
    			asm("movl %%ds,%0" : "=r" (seg));
    			return seg;
    		}
    		return task->thread.ds;
    	case offsetof(struct user_regs_struct, es):
    		if (task == current) {
    			asm("movl %%es,%0" : "=r" (seg));
    			return seg;
    		}
    		return task->thread.es;
    
    	case offsetof(struct user_regs_struct, cs):
    	case offsetof(struct user_regs_struct, ss):
    		break;
    	}
    	return *pt_regs_access(task_pt_regs(task), offset);
    }
    
    static int set_segment_reg(struct task_struct *task,
    			   unsigned long offset, u16 value)
    {
    	/*
    	 * The value argument was already truncated to 16 bits.
    	 */
    	if (invalid_selector(value))
    		return -EIO;
    
    	switch (offset) {
    	case offsetof(struct user_regs_struct,fs):
    		/*
    		 * If this is setting fs as for normal 64-bit use but
    		 * setting fs_base has implicitly changed it, leave it.
    		 */
    		if ((value == FS_TLS_SEL && task->thread.fsindex == 0 &&
    		     task->thread.fs != 0) ||
    		    (value == 0 && task->thread.fsindex == FS_TLS_SEL &&
    		     task->thread.fs == 0))
    			break;
    		task->thread.fsindex = value;
    		if (task == current)
    			loadsegment(fs, task->thread.fsindex);
    		break;
    	case offsetof(struct user_regs_struct,gs):
    		/*
    		 * If this is setting gs as for normal 64-bit use but
    		 * setting gs_base has implicitly changed it, leave it.
    		 */
    		if ((value == GS_TLS_SEL && task->thread.gsindex == 0 &&
    		     task->thread.gs != 0) ||
    		    (value == 0 && task->thread.gsindex == GS_TLS_SEL &&
    		     task->thread.gs == 0))
    			break;
    		task->thread.gsindex = value;
    		if (task == current)
    			load_gs_index(task->thread.gsindex);
    		break;
    	case offsetof(struct user_regs_struct,ds):
    		task->thread.ds = value;
    		if (task == current)
    			loadsegment(ds, task->thread.ds);
    		break;
    	case offsetof(struct user_regs_struct,es):
    		task->thread.es = value;
    		if (task == current)
    			loadsegment(es, task->thread.es);
    		break;
    
    		/*
    		 * Can't actually change these in 64-bit mode.
    		 */
    	case offsetof(struct user_regs_struct,cs):
    		if (unlikely(value == 0))
    			return -EIO;
    #ifdef CONFIG_IA32_EMULATION
    		if (test_tsk_thread_flag(task, TIF_IA32))
    			task_pt_regs(task)->cs = value;
    #endif
    		break;
    	case offsetof(struct user_regs_struct,ss):
    		if (unlikely(value == 0))
    			return -EIO;
    #ifdef CONFIG_IA32_EMULATION
    		if (test_tsk_thread_flag(task, TIF_IA32))
    			task_pt_regs(task)->ss = value;
    #endif
    		break;
    	}
    
    	return 0;
    }
    
    #endif	/* CONFIG_X86_32 */
    
    static unsigned long get_flags(struct task_struct *task)
    {
    	unsigned long retval = task_pt_regs(task)->flags;
    
    	/*
    	 * If the debugger set TF, hide it from the readout.
    	 */
    	if (test_tsk_thread_flag(task, TIF_FORCED_TF))
    		retval &= ~X86_EFLAGS_TF;
    
    	return retval;
    }
    
    static int set_flags(struct task_struct *task, unsigned long value)
    {
    	struct pt_regs *regs = task_pt_regs(task);
    
    	/*
    	 * If the user value contains TF, mark that
    	 * it was not "us" (the debugger) that set it.
    	 * If not, make sure it stays set if we had.
    	 */
    	if (value & X86_EFLAGS_TF)
    		clear_tsk_thread_flag(task, TIF_FORCED_TF);
    	else if (test_tsk_thread_flag(task, TIF_FORCED_TF))
    		value |= X86_EFLAGS_TF;
    
    	regs->flags = (regs->flags & ~FLAG_MASK) | (value & FLAG_MASK);
    
    	return 0;
    }
    
    static int putreg(struct task_struct *child,
    		  unsigned long offset, unsigned long value)
    {
    	switch (offset) {
    	case offsetof(struct user_regs_struct, cs):
    	case offsetof(struct user_regs_struct, ds):
    	case offsetof(struct user_regs_struct, es):
    	case offsetof(struct user_regs_struct, fs):
    	case offsetof(struct user_regs_struct, gs):
    	case offsetof(struct user_regs_struct, ss):
    		return set_segment_reg(child, offset, value);
    
    	case offsetof(struct user_regs_struct, flags):
    		return set_flags(child, value);
    
    #ifdef CONFIG_X86_64
    	case offsetof(struct user_regs_struct,fs_base):
    		if (value >= TASK_SIZE_OF(child))
    			return -EIO;
    		/*
    		 * When changing the segment base, use do_arch_prctl
    		 * to set either thread.fs or thread.fsindex and the
    		 * corresponding GDT slot.
    		 */
    		if (child->thread.fs != value)
    			return do_arch_prctl(child, ARCH_SET_FS, value);
    		return 0;
    	case offsetof(struct user_regs_struct,gs_base):
    		/*
    		 * Exactly the same here as the %fs handling above.
    		 */
    		if (value >= TASK_SIZE_OF(child))
    			return -EIO;
    		if (child->thread.gs != value)
    			return do_arch_prctl(child, ARCH_SET_GS, value);
    		return 0;
    #endif
    	}
    
    	*pt_regs_access(task_pt_regs(child), offset) = value;
    	return 0;
    }
    
    static unsigned long getreg(struct task_struct *task, unsigned long offset)
    {
    	switch (offset) {
    	case offsetof(struct user_regs_struct, cs):
    	case offsetof(struct user_regs_struct, ds):
    	case offsetof(struct user_regs_struct, es):
    	case offsetof(struct user_regs_struct, fs):
    	case offsetof(struct user_regs_struct, gs):
    	case offsetof(struct user_regs_struct, ss):
    		return get_segment_reg(task, offset);
    
    	case offsetof(struct user_regs_struct, flags):
    		return get_flags(task);
    
    #ifdef CONFIG_X86_64
    	case offsetof(struct user_regs_struct, fs_base): {
    		/*
    		 * do_arch_prctl may have used a GDT slot instead of
    		 * the MSR.  To userland, it appears the same either
    		 * way, except the %fs segment selector might not be 0.
    		 */
    		unsigned int seg = task->thread.fsindex;
    		if (task->thread.fs != 0)
    			return task->thread.fs;
    		if (task == current)
    			asm("movl %%fs,%0" : "=r" (seg));
    		if (seg != FS_TLS_SEL)
    			return 0;
    		return get_desc_base(&task->thread.tls_array[FS_TLS]);
    	}
    	case offsetof(struct user_regs_struct, gs_base): {
    		/*
    		 * Exactly the same here as the %fs handling above.
    		 */
    		unsigned int seg = task->thread.gsindex;
    		if (task->thread.gs != 0)
    			return task->thread.gs;
    		if (task == current)
    			asm("movl %%gs,%0" : "=r" (seg));
    		if (seg != GS_TLS_SEL)
    			return 0;
    		return get_desc_base(&task->thread.tls_array[GS_TLS]);
    	}
    #endif
    	}
    
    	return *pt_regs_access(task_pt_regs(task), offset);
    }
    
    static int genregs_get(struct task_struct *target,
    		       const struct user_regset *regset,
    		       unsigned int pos, unsigned int count,
    		       void *kbuf, void __user *ubuf)
    {
    	if (kbuf) {
    		unsigned long *k = kbuf;
    		while (count >= sizeof(*k)) {
    			*k++ = getreg(target, pos);
    			count -= sizeof(*k);
    			pos += sizeof(*k);
    		}
    	} else {
    		unsigned long __user *u = ubuf;
    		while (count >= sizeof(*u)) {
    			if (__put_user(getreg(target, pos), u++))
    				return -EFAULT;
    			count -= sizeof(*u);
    			pos += sizeof(*u);
    		}
    	}
    
    	return 0;
    }
    
    static int genregs_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 = 0;
    	if (kbuf) {
    		const unsigned long *k = kbuf;
    		while (count >= sizeof(*k) && !ret) {
    			ret = putreg(target, pos, *k++);
    			count -= sizeof(*k);
    			pos += sizeof(*k);
    		}
    	} else {
    		const unsigned long  __user *u = ubuf;
    		while (count >= sizeof(*u) && !ret) {
    			unsigned long word;
    			ret = __get_user(word, u++);
    			if (ret)
    				break;
    			ret = putreg(target, pos, word);
    			count -= sizeof(*u);
    			pos += sizeof(*u);
    		}
    	}
    	return ret;
    }
    
    static void ptrace_triggered(struct perf_event *bp,
    			     struct perf_sample_data *data,
    			     struct pt_regs *regs)
    {
    	int i;
    	struct thread_struct *thread = &(current->thread);
    
    	/*
    	 * Store in the virtual DR6 register the fact that the breakpoint
    	 * was hit so the thread's debugger will see it.
    	 */
    	for (i = 0; i < HBP_NUM; i++) {
    		if (thread->ptrace_bps[i] == bp)
    			break;
    	}
    
    	thread->debugreg6 |= (DR_TRAP0 << i);
    }
    
    /*
     * Walk through every ptrace breakpoints for this thread and
     * build the dr7 value on top of their attributes.
     *
     */
    static unsigned long ptrace_get_dr7(struct perf_event *bp[])
    {
    	int i;
    	int dr7 = 0;
    	struct arch_hw_breakpoint *info;
    
    	for (i = 0; i < HBP_NUM; i++) {
    		if (bp[i] && !bp[i]->attr.disabled) {
    			info = counter_arch_bp(bp[i]);
    			dr7 |= encode_dr7(i, info->len, info->type);
    		}
    	}
    
    	return dr7;
    }
    
    static int
    ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
    			 struct task_struct *tsk, int disabled)
    {
    	int err;
    	int gen_len, gen_type;
    	struct perf_event_attr attr;
    
    	/*
    	 * We should have at least an inactive breakpoint at this
    	 * slot. It means the user is writing dr7 without having
    	 * written the address register first
    	 */
    	if (!bp)
    		return -EINVAL;
    
    	err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
    	if (err)
    		return err;
    
    	attr = bp->attr;
    	attr.bp_len = gen_len;
    	attr.bp_type = gen_type;
    	attr.disabled = disabled;
    
    	return modify_user_hw_breakpoint(bp, &attr);
    }
    
    /*
     * Handle ptrace writes to debug register 7.
     */
    static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
    {
    	struct thread_struct *thread = &(tsk->thread);
    	unsigned long old_dr7;
    	int i, orig_ret = 0, rc = 0;
    	int enabled, second_pass = 0;
    	unsigned len, type;
    	struct perf_event *bp;
    
    	if (ptrace_get_breakpoints(tsk) < 0)
    		return -ESRCH;
    
    	data &= ~DR_CONTROL_RESERVED;
    	old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
    restore:
    	/*
    	 * Loop through all the hardware breakpoints, making the
    	 * appropriate changes to each.
    	 */
    	for (i = 0; i < HBP_NUM; i++) {
    		enabled = decode_dr7(data, i, &len, &type);
    		bp = thread->ptrace_bps[i];
    
    		if (!enabled) {
    			if (bp) {
    				/*
    				 * Don't unregister the breakpoints right-away,
    				 * unless all register_user_hw_breakpoint()
    				 * requests have succeeded. This prevents
    				 * any window of opportunity for debug
    				 * register grabbing by other users.
    				 */
    				if (!second_pass)
    					continue;
    
    				rc = ptrace_modify_breakpoint(bp, len, type,
    							      tsk, 1);
    				if (rc)
    					break;
    			}
    			continue;
    		}
    
    		rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
    		if (rc)
    			break;
    	}
    	/*
    	 * Make a second pass to free the remaining unused breakpoints
    	 * or to restore the original breakpoints if an error occurred.
    	 */
    	if (!second_pass) {
    		second_pass = 1;
    		if (rc < 0) {
    			orig_ret = rc;
    			data = old_dr7;
    		}
    		goto restore;
    	}
    
    	ptrace_put_breakpoints(tsk);
    
    	return ((orig_ret < 0) ? orig_ret : rc);
    }
    
    /*
     * Handle PTRACE_PEEKUSR calls for the debug register area.
     */
    static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
    {
    	struct thread_struct *thread = &(tsk->thread);
    	unsigned long val = 0;
    
    	if (n < HBP_NUM) {
    		struct perf_event *bp;
    
    		if (ptrace_get_breakpoints(tsk) < 0)
    			return -ESRCH;
    
    		bp = thread->ptrace_bps[n];
    		if (!bp)
    			val = 0;
    		else
    			val = bp->hw.info.address;
    
    		ptrace_put_breakpoints(tsk);
    	} else if (n == 6) {
    		val = thread->debugreg6;
    	 } else if (n == 7) {
    		val = thread->ptrace_dr7;
    	}
    	return val;
    }
    
    static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
    				      unsigned long addr)
    {
    	struct perf_event *bp;
    	struct thread_struct *t = &tsk->thread;
    	struct perf_event_attr attr;
    	int err = 0;
    
    	if (ptrace_get_breakpoints(tsk) < 0)
    		return -ESRCH;
    
    	if (!t->ptrace_bps[nr]) {
    		ptrace_breakpoint_init(&attr);
    		/*
    		 * Put stub len and type to register (reserve) an inactive but
    		 * correct bp
    		 */
    		attr.bp_addr = addr;
    		attr.bp_len = HW_BREAKPOINT_LEN_1;
    		attr.bp_type = HW_BREAKPOINT_W;
    		attr.disabled = 1;
    
    		bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
    						 NULL, tsk);
    
    		/*
    		 * CHECKME: the previous code returned -EIO if the addr wasn't
    		 * a valid task virtual addr. The new one will return -EINVAL in
    		 *  this case.
    		 * -EINVAL may be what we want for in-kernel breakpoints users,
    		 * but -EIO looks better for ptrace, since we refuse a register
    		 * writing for the user. And anyway this is the previous
    		 * behaviour.
    		 */
    		if (IS_ERR(bp)) {
    			err = PTR_ERR(bp);
    			goto put;
    		}
    
    		t->ptrace_bps[nr] = bp;
    	} else {
    		bp = t->ptrace_bps[nr];
    
    		attr = bp->attr;
    		attr.bp_addr = addr;
    		err = modify_user_hw_breakpoint(bp, &attr);
    	}
    
    put:
    	ptrace_put_breakpoints(tsk);
    	return err;
    }
    
    /*
     * Handle PTRACE_POKEUSR calls for the debug register area.
     */
    static int ptrace_set_debugreg(struct task_struct *tsk, int n,
    			       unsigned long val)
    {
    	struct thread_struct *thread = &(tsk->thread);
    	int rc = 0;
    
    	/* There are no DR4 or DR5 registers */
    	if (n == 4 || n == 5)
    		return -EIO;
    
    	if (n == 6) {
    		thread->debugreg6 = val;
    		goto ret_path;
    	}
    	if (n < HBP_NUM) {
    		rc = ptrace_set_breakpoint_addr(tsk, n, val);
    		if (rc)
    			return rc;
    	}
    	/* All that's left is DR7 */
    	if (n == 7) {
    		rc = ptrace_write_dr7(tsk, val);
    		if (!rc)
    			thread->ptrace_dr7 = val;
    	}
    
    ret_path:
    	return rc;
    }
    
    /*
     * These access the current or another (stopped) task's io permission
     * bitmap for debugging or core dump.
     */
    static int ioperm_active(struct task_struct *target,
    			 const struct user_regset *regset)
    {
    	return target->thread.io_bitmap_max / regset->size;
    }
    
    static int ioperm_get(struct task_struct *target,
    		      const struct user_regset *regset,
    		      unsigned int pos, unsigned int count,
    		      void *kbuf, void __user *ubuf)
    {
    	if (!target->thread.io_bitmap_ptr)
    		return -ENXIO;
    
    	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
    				   target->thread.io_bitmap_ptr,
    				   0, IO_BITMAP_BYTES);
    }
    
    /*
     * Called by kernel/ptrace.c when detaching..
     *
     * Make sure the single step bit is not set.
     */
    void ptrace_disable(struct task_struct *child)
    {
    	user_disable_single_step(child);
    #ifdef TIF_SYSCALL_EMU
    	clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
    #endif
    }
    
    #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
    static const struct user_regset_view user_x86_32_view; /* Initialized below. */
    #endif
    
    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) {
    	/* read the word at location addr in the USER area. */
    	case PTRACE_PEEKUSR: {
    		unsigned long tmp;
    
    		ret = -EIO;
    		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
    			break;
    
    		tmp = 0;  /* Default return condition */
    		if (addr < sizeof(struct user_regs_struct))
    			tmp = getreg(child, addr);
    		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
    			 addr <= offsetof(struct user, u_debugreg[7])) {
    			addr -= offsetof(struct user, u_debugreg[0]);
    			tmp = ptrace_get_debugreg(child, addr / sizeof(data));
    		}
    		ret = put_user(tmp, datap);
    		break;
    	}
    
    	case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
    		ret = -EIO;
    		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user))
    			break;
    
    		if (addr < sizeof(struct user_regs_struct))
    			ret = putreg(child, addr, data);
    		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
    			 addr <= offsetof(struct user, u_debugreg[7])) {
    			addr -= offsetof(struct user, u_debugreg[0]);
    			ret = ptrace_set_debugreg(child,
    						  addr / sizeof(data), data);
    		}
    		break;
    
    	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
    		return copy_regset_to_user(child,
    					   task_user_regset_view(current),
    					   REGSET_GENERAL,
    					   0, sizeof(struct user_regs_struct),
    					   datap);
    
    	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
    		return copy_regset_from_user(child,
    					     task_user_regset_view(current),
    					     REGSET_GENERAL,
    					     0, sizeof(struct user_regs_struct),
    					     datap);
    
    	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
    		return copy_regset_to_user(child,
    					   task_user_regset_view(current),
    					   REGSET_FP,
    					   0, sizeof(struct user_i387_struct),
    					   datap);
    
    	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
    		return copy_regset_from_user(child,
    					     task_user_regset_view(current),
    					     REGSET_FP,
    					     0, sizeof(struct user_i387_struct),
    					     datap);
    
    #ifdef CONFIG_X86_32
    	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
    		return copy_regset_to_user(child, &user_x86_32_view,
    					   REGSET_XFP,
    					   0, sizeof(struct user_fxsr_struct),
    					   datap) ? -EIO : 0;
    
    	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
    		return copy_regset_from_user(child, &user_x86_32_view,
    					     REGSET_XFP,
    					     0, sizeof(struct user_fxsr_struct),
    					     datap) ? -EIO : 0;
    #endif
    
    #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
    	case PTRACE_GET_THREAD_AREA:
    		if ((int) addr < 0)
    			return -EIO;
    		ret = do_get_thread_area(child, addr,
    					(struct user_desc __user *)data);
    		break;
    
    	case PTRACE_SET_THREAD_AREA:
    		if ((int) addr < 0)
    			return -EIO;
    		ret = do_set_thread_area(child, addr,
    					(struct user_desc __user *)data, 0);
    		break;
    #endif
    
    #ifdef CONFIG_X86_64
    		/* normal 64bit interface to access TLS data.
    		   Works just like arch_prctl, except that the arguments
    		   are reversed. */
    	case PTRACE_ARCH_PRCTL:
    		ret = do_arch_prctl(child, data, addr);
    		break;
    #endif
    
    	default:
    		ret = ptrace_request(child, request, addr, data);
    		break;
    	}
    
    	return ret;
    }
    
    #ifdef CONFIG_IA32_EMULATION
    
    #include <linux/compat.h>
    #include <linux/syscalls.h>
    #include <asm/ia32.h>
    #include <asm/user32.h>
    
    #define R32(l,q)							\
    	case offsetof(struct user32, regs.l):				\
    		regs->q = value; break
    
    #define SEG32(rs)							\
    	case offsetof(struct user32, regs.rs):				\
    		return set_segment_reg(child,				\
    				       offsetof(struct user_regs_struct, rs), \
    				       value);				\
    		break
    
    static int putreg32(struct task_struct *child, unsigned regno, u32 value)
    {
    	struct pt_regs *regs = task_pt_regs(child);
    
    	switch (regno) {
    
    	SEG32(cs);
    	SEG32(ds);
    	SEG32(es);
    	SEG32(fs);
    	SEG32(gs);
    	SEG32(ss);
    
    	R32(ebx, bx);
    	R32(ecx, cx);
    	R32(edx, dx);
    	R32(edi, di);
    	R32(esi, si);
    	R32(ebp, bp);
    	R32(eax, ax);
    	R32(eip, ip);
    	R32(esp, sp);
    
    	case offsetof(struct user32, regs.orig_eax):
    		/*
    		 * A 32-bit debugger setting orig_eax means to restore
    		 * the state of the task restarting a 32-bit syscall.
    		 * Make sure we interpret the -ERESTART* codes correctly
    		 * in case the task is not actually still sitting at the
    		 * exit from a 32-bit syscall with TS_COMPAT still set.
    		 */
    		regs->orig_ax = value;
    		if (syscall_get_nr(child, regs) >= 0)
    			task_thread_info(child)->status |= TS_COMPAT;
    		break;
    
    	case offsetof(struct user32, regs.eflags):
    		return set_flags(child, value);
    
    	case offsetof(struct user32, u_debugreg[0]) ...
    		offsetof(struct user32, u_debugreg[7]):
    		regno -= offsetof(struct user32, u_debugreg[0]);
    		return ptrace_set_debugreg(child, regno / 4, value);
    
    	default:
    		if (regno > sizeof(struct user32) || (regno & 3))
    			return -EIO;
    
    		/*
    		 * Other dummy fields in the virtual user structure
    		 * are ignored
    		 */
    		break;
    	}
    	return 0;
    }
    
    #undef R32
    #undef SEG32
    
    #define R32(l,q)							\
    	case offsetof(struct user32, regs.l):				\
    		*val = regs->q; break
    
    #define SEG32(rs)							\
    	case offsetof(struct user32, regs.rs):				\
    		*val = get_segment_reg(child,				\
    				       offsetof(struct user_regs_struct, rs)); \
    		break
    
    static int getreg32(struct task_struct *child, unsigned regno, u32 *val)
    {
    	struct pt_regs *regs = task_pt_regs(child);
    
    	switch (regno) {
    
    	SEG32(ds);
    	SEG32(es);
    	SEG32(fs);
    	SEG32(gs);
    
    	R32(cs, cs);
    	R32(ss, ss);
    	R32(ebx, bx);
    	R32(ecx, cx);
    	R32(edx, dx);
    	R32(edi, di);
    	R32(esi, si);
    	R32(ebp, bp);
    	R32(eax, ax);
    	R32(orig_eax, orig_ax);
    	R32(eip, ip);
    	R32(esp, sp);
    
    	case offsetof(struct user32, regs.eflags):
    		*val = get_flags(child);
    		break;
    
    	case offsetof(struct user32, u_debugreg[0]) ...
    		offsetof(struct user32, u_debugreg[7]):
    		regno -= offsetof(struct user32, u_debugreg[0]);
    		*val = ptrace_get_debugreg(child, regno / 4);
    		break;
    
    	default:
    		if (regno > sizeof(struct user32) || (regno & 3))
    			return -EIO;
    
    		/*
    		 * Other dummy fields in the virtual user structure
    		 * are ignored
    		 */
    		*val = 0;
    		break;
    	}
    	return 0;
    }
    
    #undef R32
    #undef SEG32
    
    static int genregs32_get(struct task_struct *target,
    			 const struct user_regset *regset,
    			 unsigned int pos, unsigned int count,
    			 void *kbuf, void __user *ubuf)
    {
    	if (kbuf) {
    		compat_ulong_t *k = kbuf;
    		while (count >= sizeof(*k)) {
    			getreg32(target, pos, k++);
    			count -= sizeof(*k);
    			pos += sizeof(*k);
    		}
    	} else {
    		compat_ulong_t __user *u = ubuf;
    		while (count >= sizeof(*u)) {
    			compat_ulong_t word;
    			getreg32(target, pos, &word);
    			if (__put_user(word, u++))
    				return -EFAULT;
    			count -= sizeof(*u);
    			pos += sizeof(*u);
    		}
    	}
    
    	return 0;
    }
    
    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)
    {
    	int ret = 0;
    	if (kbuf) {
    		const compat_ulong_t *k = kbuf;
    		while (count >= sizeof(*k) && !ret) {
    			ret = putreg32(target, pos, *k++);
    			count -= sizeof(*k);
    			pos += sizeof(*k);
    		}
    	} else {
    		const compat_ulong_t __user *u = ubuf;
    		while (count >= sizeof(*u) && !ret) {
    			compat_ulong_t word;
    			ret = __get_user(word, u++);
    			if (ret)
    				break;
    			ret = putreg32(target, pos, word);
    			count -= sizeof(*u);
    			pos += sizeof(*u);
    		}
    	}
    	return ret;
    }
    
    #ifdef CONFIG_X86_X32_ABI
    static long x32_arch_ptrace(struct task_struct *child,
    			    compat_long_t request, compat_ulong_t caddr,
    			    compat_ulong_t cdata)
    {
    	unsigned long addr = caddr;
    	unsigned long data = cdata;
    	void __user *datap = compat_ptr(data);
    	int ret;
    
    	switch (request) {
    	/* Read 32bits at location addr in the USER area.  Only allow
    	   to return the lower 32bits of segment and debug registers.  */
    	case PTRACE_PEEKUSR: {
    		u32 tmp;
    
    		ret = -EIO;
    		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
    		    addr < offsetof(struct user_regs_struct, cs))
    			break;
    
    		tmp = 0;  /* Default return condition */
    		if (addr < sizeof(struct user_regs_struct))
    			tmp = getreg(child, addr);
    		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
    			 addr <= offsetof(struct user, u_debugreg[7])) {
    			addr -= offsetof(struct user, u_debugreg[0]);
    			tmp = ptrace_get_debugreg(child, addr / sizeof(data));
    		}
    		ret = put_user(tmp, (__u32 __user *)datap);
    		break;
    	}
    
    	/* Write the word at location addr in the USER area.  Only allow
    	   to update segment and debug registers with the upper 32bits
    	   zero-extended. */
    	case PTRACE_POKEUSR:
    		ret = -EIO;
    		if ((addr & (sizeof(data) - 1)) || addr >= sizeof(struct user) ||
    		    addr < offsetof(struct user_regs_struct, cs))
    			break;
    
    		if (addr < sizeof(struct user_regs_struct))
    			ret = putreg(child, addr, data);
    		else if (addr >= offsetof(struct user, u_debugreg[0]) &&
    			 addr <= offsetof(struct user, u_debugreg[7])) {
    			addr -= offsetof(struct user, u_debugreg[0]);
    			ret = ptrace_set_debugreg(child,
    						  addr / sizeof(data), data);
    		}
    		break;
    
    	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
    		return copy_regset_to_user(child,
    					   task_user_regset_view(current),
    					   REGSET_GENERAL,
    					   0, sizeof(struct user_regs_struct),
    					   datap);
    
    	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
    		return copy_regset_from_user(child,
    					     task_user_regset_view(current),
    					     REGSET_GENERAL,
    					     0, sizeof(struct user_regs_struct),
    					     datap);
    
    	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
    		return copy_regset_to_user(child,
    					   task_user_regset_view(current),
    					   REGSET_FP,
    					   0, sizeof(struct user_i387_struct),
    					   datap);
    
    	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
    		return copy_regset_from_user(child,
    					     task_user_regset_view(current),
    					     REGSET_FP,
    					     0, sizeof(struct user_i387_struct),
    					     datap);
    
    		/* normal 64bit interface to access TLS data.
    		   Works just like arch_prctl, except that the arguments
    		   are reversed. */
    	case PTRACE_ARCH_PRCTL:
    		return do_arch_prctl(child, data, addr);
    
    	default:
    		return compat_ptrace_request(child, request, addr, data);
    	}
    
    	return ret;
    }
    #endif
    
    long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
    			compat_ulong_t caddr, compat_ulong_t cdata)
    {
    	unsigned long addr = caddr;
    	unsigned long data = cdata;
    	void __user *datap = compat_ptr(data);
    	int ret;
    	__u32 val;
    
    #ifdef CONFIG_X86_X32_ABI
    	if (!is_ia32_task())
    		return x32_arch_ptrace(child, request, caddr, cdata);
    #endif
    
    	switch (request) {
    	case PTRACE_PEEKUSR:
    		ret = getreg32(child, addr, &val);
    		if (ret == 0)
    			ret = put_user(val, (__u32 __user *)datap);
    		break;
    
    	case PTRACE_POKEUSR:
    		ret = putreg32(child, addr, data);
    		break;
    
    	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
    		return copy_regset_to_user(child, &user_x86_32_view,
    					   REGSET_GENERAL,
    					   0, sizeof(struct user_regs_struct32),
    					   datap);
    
    	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
    		return copy_regset_from_user(child, &user_x86_32_view,
    					     REGSET_GENERAL, 0,
    					     sizeof(struct user_regs_struct32),
    					     datap);
    
    	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
    		return copy_regset_to_user(child, &user_x86_32_view,
    					   REGSET_FP, 0,
    					   sizeof(struct user_i387_ia32_struct),
    					   datap);
    
    	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
    		return copy_regset_from_user(
    			child, &user_x86_32_view, REGSET_FP,
    			0, sizeof(struct user_i387_ia32_struct), datap);
    
    	case PTRACE_GETFPXREGS:	/* Get the child extended FPU state. */
    		return copy_regset_to_user(child, &user_x86_32_view,
    					   REGSET_XFP, 0,
    					   sizeof(struct user32_fxsr_struct),
    					   datap);
    
    	case PTRACE_SETFPXREGS:	/* Set the child extended FPU state. */
    		return copy_regset_from_user(child, &user_x86_32_view,
    					     REGSET_XFP, 0,
    					     sizeof(struct user32_fxsr_struct),
    					     datap);
    
    	case PTRACE_GET_THREAD_AREA:
    	case PTRACE_SET_THREAD_AREA:
    		return arch_ptrace(child, request, addr, data);
    
    	default:
    		return compat_ptrace_request(child, request, addr, data);
    	}
    
    	return ret;
    }
    
    #endif	/* CONFIG_IA32_EMULATION */
    
    #ifdef CONFIG_X86_64
    
    static struct user_regset x86_64_regsets[] __read_mostly = {
    	[REGSET_GENERAL] = {
    		.core_note_type = NT_PRSTATUS,
    		.n = sizeof(struct user_regs_struct) / sizeof(long),
    		.size = sizeof(long), .align = sizeof(long),
    		.get = genregs_get, .set = genregs_set
    	},
    	[REGSET_FP] = {
    		.core_note_type = NT_PRFPREG,
    		.n = sizeof(struct user_i387_struct) / sizeof(long),
    		.size = sizeof(long), .align = sizeof(long),
    		.active = xfpregs_active, .get = xfpregs_get, .set = xfpregs_set
    	},
    	[REGSET_XSTATE] = {
    		.core_note_type = NT_X86_XSTATE,
    		.size = sizeof(u64), .align = sizeof(u64),
    		.active = xstateregs_active, .get = xstateregs_get,
    		.set = xstateregs_set
    	},
    	[REGSET_IOPERM64] = {
    		.core_note_type = NT_386_IOPERM,
    		.n = IO_BITMAP_LONGS,
    		.size = sizeof(long), .align = sizeof(long),
    		.active = ioperm_active, .get = ioperm_get
    	},
    };
    
    static const struct user_regset_view user_x86_64_view = {
    	.name = "x86_64", .e_machine = EM_X86_64,
    	.regsets = x86_64_regsets, .n = ARRAY_SIZE(x86_64_regsets)
    };
    
    #else  /* CONFIG_X86_32 */
    
    #define user_regs_struct32	user_regs_struct
    #define genregs32_get		genregs_get
    #define genregs32_set		genregs_set
    
    #define user_i387_ia32_struct	user_i387_struct
    #define user32_fxsr_struct	user_fxsr_struct
    
    #endif	/* CONFIG_X86_64 */
    
    #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
    static struct user_regset x86_32_regsets[] __read_mostly = {
    	[REGSET_GENERAL] = {
    		.core_note_type = NT_PRSTATUS,
    		.n = sizeof(struct user_regs_struct32) / sizeof(u32),
    		.size = sizeof(u32), .align = sizeof(u32),
    		.get = genregs32_get, .set = genregs32_set
    	},
    	[REGSET_FP] = {
    		.core_note_type = NT_PRFPREG,
    		.n = sizeof(struct user_i387_ia32_struct) / sizeof(u32),
    		.size = sizeof(u32), .align = sizeof(u32),
    		.active = fpregs_active, .get = fpregs_get, .set = fpregs_set
    	},
    	[REGSET_XFP] = {
    		.core_note_type = NT_PRXFPREG,
    		.n = sizeof(struct user32_fxsr_struct) / sizeof(u32),
    		.size = sizeof(u32), .align = sizeof(u32),
    		.active = xfpregs_active, .get = xfpregs_get, .set = xfpregs_set
    	},
    	[REGSET_XSTATE] = {
    		.core_note_type = NT_X86_XSTATE,
    		.size = sizeof(u64), .align = sizeof(u64),
    		.active = xstateregs_active, .get = xstateregs_get,
    		.set = xstateregs_set
    	},
    	[REGSET_TLS] = {
    		.core_note_type = NT_386_TLS,
    		.n = GDT_ENTRY_TLS_ENTRIES, .bias = GDT_ENTRY_TLS_MIN,
    		.size = sizeof(struct user_desc),
    		.align = sizeof(struct user_desc),
    		.active = regset_tls_active,
    		.get = regset_tls_get, .set = regset_tls_set
    	},
    	[REGSET_IOPERM32] = {
    		.core_note_type = NT_386_IOPERM,
    		.n = IO_BITMAP_BYTES / sizeof(u32),
    		.size = sizeof(u32), .align = sizeof(u32),
    		.active = ioperm_active, .get = ioperm_get
    	},
    };
    
    static const struct user_regset_view user_x86_32_view = {
    	.name = "i386", .e_machine = EM_386,
    	.regsets = x86_32_regsets, .n = ARRAY_SIZE(x86_32_regsets)
    };
    #endif
    
    /*
     * This represents bytes 464..511 in the memory layout exported through
     * the REGSET_XSTATE interface.
     */
    u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
    
    void update_regset_xstate_info(unsigned int size, u64 xstate_mask)
    {
    #ifdef CONFIG_X86_64
    	x86_64_regsets[REGSET_XSTATE].n = size / sizeof(u64);
    #endif
    #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
    	x86_32_regsets[REGSET_XSTATE].n = size / sizeof(u64);
    #endif
    	xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
    }
    
    const struct user_regset_view *task_user_regset_view(struct task_struct *task)
    {
    #ifdef CONFIG_IA32_EMULATION
    	if (test_tsk_thread_flag(task, TIF_IA32))
    #endif
    #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
    		return &user_x86_32_view;
    #endif
    #ifdef CONFIG_X86_64
    	return &user_x86_64_view;
    #endif
    }
    
    static void fill_sigtrap_info(struct task_struct *tsk,
    				struct pt_regs *regs,
    				int error_code, int si_code,
    				struct siginfo *info)
    {
    	tsk->thread.trap_nr = X86_TRAP_DB;
    	tsk->thread.error_code = error_code;
    
    	memset(info, 0, sizeof(*info));
    	info->si_signo = SIGTRAP;
    	info->si_code = si_code;
    	info->si_addr = user_mode_vm(regs) ? (void __user *)regs->ip : NULL;
    }
    
    void user_single_step_siginfo(struct task_struct *tsk,
    				struct pt_regs *regs,
    				struct siginfo *info)
    {
    	fill_sigtrap_info(tsk, regs, 0, TRAP_BRKPT, info);
    }
    
    void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
    					 int error_code, int si_code)
    {
    	struct siginfo info;
    
    	fill_sigtrap_info(tsk, regs, error_code, si_code, &info);
    	/* Send us the fake SIGTRAP */
    	force_sig_info(SIGTRAP, &info, tsk);
    }
    
    
    #ifdef CONFIG_X86_32
    # define IS_IA32	1
    #elif defined CONFIG_IA32_EMULATION
    # define IS_IA32	is_compat_task()
    #else
    # define IS_IA32	0
    #endif
    
    /*
     * We must return the syscall number to actually look up in the table.
     * This can be -1L to skip running any syscall at all.
     */
    long syscall_trace_enter(struct pt_regs *regs)
    {
    	long ret = 0;
    
    	/*
    	 * If we stepped into a sysenter/syscall insn, it trapped in
    	 * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP.
    	 * If user-mode had set TF itself, then it's still clear from
    	 * do_debug() and we need to set it again to restore the user
    	 * state.  If we entered on the slow path, TF was already set.
    	 */
    	if (test_thread_flag(TIF_SINGLESTEP))
    		regs->flags |= X86_EFLAGS_TF;
    
    	/* do the secure computing check first */
    	if (secure_computing(regs->orig_ax)) {
    		/* seccomp failures shouldn't expose any additional code. */
    		ret = -1L;
    		goto out;
    	}
    
    	if (unlikely(test_thread_flag(TIF_SYSCALL_EMU)))
    		ret = -1L;
    
    	if ((ret || test_thread_flag(TIF_SYSCALL_TRACE)) &&
    	    tracehook_report_syscall_entry(regs))
    		ret = -1L;
    
    	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
    		trace_sys_enter(regs, regs->orig_ax);
    
    	if (IS_IA32)
    		audit_syscall_entry(AUDIT_ARCH_I386,
    				    regs->orig_ax,
    				    regs->bx, regs->cx,
    				    regs->dx, regs->si);
    #ifdef CONFIG_X86_64
    	else
    		audit_syscall_entry(AUDIT_ARCH_X86_64,
    				    regs->orig_ax,
    				    regs->di, regs->si,
    				    regs->dx, regs->r10);
    #endif
    
    out:
    	return ret ?: regs->orig_ax;
    }
    
    void syscall_trace_leave(struct pt_regs *regs)
    {
    	bool step;
    
    	audit_syscall_exit(regs);
    
    	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
    		trace_sys_exit(regs, regs->ax);
    
    	/*
    	 * If TIF_SYSCALL_EMU is set, we only get here because of
    	 * TIF_SINGLESTEP (i.e. this is PTRACE_SYSEMU_SINGLESTEP).
    	 * We already reported this syscall instruction in
    	 * syscall_trace_enter().
    	 */
    	step = unlikely(test_thread_flag(TIF_SINGLESTEP)) &&
    			!test_thread_flag(TIF_SYSCALL_EMU);
    	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
    		tracehook_report_syscall_exit(regs, step);
    }