[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / kernel / signal_64.c

/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 *  2000-2002   x86-64 support by Andi Kleen
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/compiler.h>
#include <asm/processor.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include <asm/proto.h>
#include <asm/ia32_unistd.h>
#include <asm/mce.h>
#include <asm/syscalls.h>
#include "sigframe.h"

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

#define __FIX_EFLAGS	(X86_EFLAGS_AC | X86_EFLAGS_OF | \
			 X86_EFLAGS_DF | X86_EFLAGS_TF | X86_EFLAGS_SF | \
			 X86_EFLAGS_ZF | X86_EFLAGS_AF | X86_EFLAGS_PF | \
			 X86_EFLAGS_CF)

#ifdef CONFIG_X86_32
# define FIX_EFLAGS	(__FIX_EFLAGS | X86_EFLAGS_RF)
#else
# define FIX_EFLAGS	__FIX_EFLAGS
#endif

int ia32_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
               sigset_t *set, struct pt_regs * regs); 
int ia32_setup_frame(int sig, struct k_sigaction *ka,
            sigset_t *set, struct pt_regs * regs); 

asmlinkage long
sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
		struct pt_regs *regs)
{
	return do_sigaltstack(uss, uoss, regs->sp);
}

/*
 * Signal frame handlers.
 */

static inline int save_i387(struct _fpstate __user *buf)
{
	struct task_struct *tsk = current;
	int err = 0;

	BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
			sizeof(tsk->thread.xstate->fxsave));

	if ((unsigned long)buf % 16)
		printk("save_i387: bad fpstate %p\n", buf);

	if (!used_math())
		return 0;
	clear_used_math(); /* trigger finit */
	if (task_thread_info(tsk)->status & TS_USEDFPU) {
		err = save_i387_checking((struct i387_fxsave_struct __user *)
					 buf);
		if (err)
			return err;
		task_thread_info(tsk)->status &= ~TS_USEDFPU;
		stts();
	} else {
		if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
				   sizeof(struct i387_fxsave_struct)))
			return -1;
	}
	return 1;
}

/*
 * This restores directly out of user space. Exceptions are handled.
 */
static inline int restore_i387(struct _fpstate __user *buf)
{
	struct task_struct *tsk = current;
	int err;

	if (!used_math()) {
		err = init_fpu(tsk);
		if (err)
			return err;
	}

	if (!(task_thread_info(current)->status & TS_USEDFPU)) {
		clts();
		task_thread_info(current)->status |= TS_USEDFPU;
	}
	err = restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
	if (unlikely(err)) {
		/*
		 * Encountered an error while doing the restore from the
		 * user buffer, clear the fpu state.
		 */
		clear_fpu(tsk);
		clear_used_math();
	}
	return err;
}

/*
 * Do a signal return; undo the signal stack.
 */
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
		   unsigned long *pax)
{
	unsigned int err = 0;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

#define COPY(x)		err |= __get_user(regs->x, &sc->x)

	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
	COPY(dx); COPY(cx); COPY(ip);
	COPY(r8);
	COPY(r9);
	COPY(r10);
	COPY(r11);
	COPY(r12);
	COPY(r13);
	COPY(r14);
	COPY(r15);

	/* Kernel saves and restores only the CS segment register on signals,
	 * which is the bare minimum needed to allow mixed 32/64-bit code.
	 * App's signal handler can save/restore other segments if needed. */
	{
		unsigned cs;
		err |= __get_user(cs, &sc->cs);
		regs->cs = cs | 3;	/* Force into user mode */
	}

	{
		unsigned int tmpflags;
		err |= __get_user(tmpflags, &sc->flags);
		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
		regs->orig_ax = -1;		/* disable syscall checks */
	}

	{
		struct _fpstate __user * buf;
		err |= __get_user(buf, &sc->fpstate);

		if (buf) {
			if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
				goto badframe;
			err |= restore_i387(buf);
		} else {
			struct task_struct *me = current;
			if (used_math()) {
				clear_fpu(me);
				clear_used_math();
			}
		}
	}

	err |= __get_user(*pax, &sc->ax);
	return err;

badframe:
	return 1;
}

asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	sigset_t set;
	unsigned long ax;

	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	
	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
		goto badframe;

	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
		goto badframe;

	return ax;

badframe:
	signal_fault(regs,frame,"sigreturn");
	return 0;
}	

/*
 * Set up a signal frame.
 */

static inline int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, unsigned long mask, struct task_struct *me)
{
	int err = 0;

	err |= __put_user(regs->cs, &sc->cs);
	err |= __put_user(0, &sc->gs);
	err |= __put_user(0, &sc->fs);

	err |= __put_user(regs->di, &sc->di);
	err |= __put_user(regs->si, &sc->si);
	err |= __put_user(regs->bp, &sc->bp);
	err |= __put_user(regs->sp, &sc->sp);
	err |= __put_user(regs->bx, &sc->bx);
	err |= __put_user(regs->dx, &sc->dx);
	err |= __put_user(regs->cx, &sc->cx);
	err |= __put_user(regs->ax, &sc->ax);
	err |= __put_user(regs->r8, &sc->r8);
	err |= __put_user(regs->r9, &sc->r9);
	err |= __put_user(regs->r10, &sc->r10);
	err |= __put_user(regs->r11, &sc->r11);
	err |= __put_user(regs->r12, &sc->r12);
	err |= __put_user(regs->r13, &sc->r13);
	err |= __put_user(regs->r14, &sc->r14);
	err |= __put_user(regs->r15, &sc->r15);
	err |= __put_user(me->thread.trap_no, &sc->trapno);
	err |= __put_user(me->thread.error_code, &sc->err);
	err |= __put_user(regs->ip, &sc->ip);
	err |= __put_user(regs->flags, &sc->flags);
	err |= __put_user(mask, &sc->oldmask);
	err |= __put_user(me->thread.cr2, &sc->cr2);

	return err;
}

/*
 * Determine which stack to use..
 */

static void __user *
get_stack(struct k_sigaction *ka, struct pt_regs *regs, unsigned long size)
{
	unsigned long sp;

	/* Default to using normal stack - redzone*/
	sp = regs->sp - 128;

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (sas_ss_flags(sp) == 0)
			sp = current->sas_ss_sp + current->sas_ss_size;
	}

	return (void __user *)round_down(sp - size, 16);
}

static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs * regs)
{
	struct rt_sigframe __user *frame;
	struct _fpstate __user *fp = NULL; 
	int err = 0;
	struct task_struct *me = current;

	if (used_math()) {
		fp = get_stack(ka, regs, sizeof(struct _fpstate)); 
		frame = (void __user *)round_down(
			(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;

		if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
			goto give_sigsegv;

		if (save_i387(fp) < 0) 
			err |= -1; 
	} else
		frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
		goto give_sigsegv;

	if (ka->sa.sa_flags & SA_SIGINFO) { 
		err |= copy_siginfo_to_user(&frame->info, info);
		if (err)
			goto give_sigsegv;
	}
		
	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(0, &frame->uc.uc_link);
	err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->sp),
			  &frame->uc.uc_stack.ss_flags);
	err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
	err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
	if (sizeof(*set) == 16) { 
		__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
		__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); 
	} else
		err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	/* x86-64 should always use SA_RESTORER. */
	if (ka->sa.sa_flags & SA_RESTORER) {
		err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
	} else {
		/* could use a vstub here */
		goto give_sigsegv; 
	}

	if (err)
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->di = sig;
	/* In case the signal handler was declared without prototypes */ 
	regs->ax = 0;

	/* This also works for non SA_SIGINFO handlers because they expect the
	   next argument after the signal number on the stack. */
	regs->si = (unsigned long)&frame->info;
	regs->dx = (unsigned long)&frame->uc;
	regs->ip = (unsigned long) ka->sa.sa_handler;

	regs->sp = (unsigned long)frame;

	/* Set up the CS register to run signal handlers in 64-bit mode,
	   even if the handler happens to be interrupting 32-bit code. */
	regs->cs = __USER_CS;

	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

/*
 * Return -1L or the syscall number that @regs is executing.
 */
static long current_syscall(struct pt_regs *regs)
{
	/*
	 * We always sign-extend a -1 value being set here,
	 * so this is always either -1L or a syscall number.
	 */
	return regs->orig_ax;
}

/*
 * Return a value that is -EFOO if the system call in @regs->orig_ax
 * returned an error.  This only works for @regs from @current.
 */
static long current_syscall_ret(struct pt_regs *regs)
{
#ifdef CONFIG_IA32_EMULATION
	if (test_thread_flag(TIF_IA32))
		/*
		 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
		 * and will match correctly in comparisons.
		 */
		return (int) regs->ax;
#endif
	return regs->ax;
}

/*
 * OK, we're invoking a handler
 */	

static int
handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka,
	      sigset_t *oldset, struct pt_regs *regs)
{
	int ret;

	/* Are we from a system call? */
	if (current_syscall(regs) >= 0) {
		/* If so, check system call restarting.. */
		switch (current_syscall_ret(regs)) {
		case -ERESTART_RESTARTBLOCK:
		case -ERESTARTNOHAND:
			regs->ax = -EINTR;
			break;

		case -ERESTARTSYS:
			if (!(ka->sa.sa_flags & SA_RESTART)) {
				regs->ax = -EINTR;
				break;
			}
		/* fallthrough */
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;
		}
	}

	/*
	 * If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
	 * flag so that register information in the sigcontext is correct.
	 */
	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
	    likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
		regs->flags &= ~X86_EFLAGS_TF;

#ifdef CONFIG_IA32_EMULATION
	if (test_thread_flag(TIF_IA32)) {
		if (ka->sa.sa_flags & SA_SIGINFO)
			ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
		else
			ret = ia32_setup_frame(sig, ka, oldset, regs);
	} else 
#endif
	ret = setup_rt_frame(sig, ka, info, oldset, regs);

	if (ret == 0) {
		/*
		 * This has nothing to do with segment registers,
		 * despite the name.  This magic affects uaccess.h
		 * macros' behavior.  Reset it to the normal setting.
		 */
		set_fs(USER_DS);

		/*
		 * Clear the direction flag as per the ABI for function entry.
		 */
		regs->flags &= ~X86_EFLAGS_DF;

		/*
		 * Clear TF when entering the signal handler, but
		 * notify any tracer that was single-stepping it.
		 * The tracer may want to single-step inside the
		 * handler too.
		 */
		regs->flags &= ~X86_EFLAGS_TF;
		if (test_thread_flag(TIF_SINGLESTEP))
			ptrace_notify(SIGTRAP);

		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		if (!(ka->sa.sa_flags & SA_NODEFER))
			sigaddset(&current->blocked,sig);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}

	return ret;
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 */
static void do_signal(struct pt_regs *regs)
{
	struct k_sigaction ka;
	siginfo_t info;
	int signr;
	sigset_t *oldset;

	/*
	 * We want the common case to go fast, which is why we may in certain
	 * cases get here from kernel mode. Just return without doing anything
	 * if so.
	 * X86_32: vm86 regs switched out by assembly code before reaching
	 * here, so testing against kernel CS suffices.
	 */
	if (!user_mode(regs))
		return;

	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
		oldset = &current->saved_sigmask;
	else
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
		/* Re-enable any watchpoints before delivering the
		 * signal to user space. The processor register will
		 * have been cleared if the watchpoint triggered
		 * inside the kernel.
		 */
		if (current->thread.debugreg7)
			set_debugreg(current->thread.debugreg7, 7);

		/* Whee!  Actually deliver the signal.  */
		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
			/*
			 * A signal was successfully delivered; the saved
			 * sigmask will have been stored in the signal frame,
			 * and will be restored by sigreturn, so we can simply
			 * clear the TS_RESTORE_SIGMASK flag.
			 */
			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
		}
		return;
	}

	/* Did we come from a system call? */
	if (current_syscall(regs) >= 0) {
		/* Restart the system call - no handlers present */
		switch (current_syscall_ret(regs)) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			regs->ax = regs->orig_ax;
			regs->ip -= 2;
			break;
		case -ERESTART_RESTARTBLOCK:
			regs->ax = test_thread_flag(TIF_IA32) ?
					__NR_ia32_restart_syscall :
					__NR_restart_syscall;
			regs->ip -= 2;
			break;
		}
	}

	/*
	 * If there's no signal to deliver, we just put the saved sigmask
	 * back.
	 */
	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}
}

void do_notify_resume(struct pt_regs *regs, void *unused,
		      __u32 thread_info_flags)
{
#ifdef CONFIG_X86_MCE
	/* notify userspace of pending MCEs */
	if (thread_info_flags & _TIF_MCE_NOTIFY)
		mce_notify_user();
#endif /* CONFIG_X86_MCE */

	/* deal with pending signal delivery */
	if (thread_info_flags & _TIF_SIGPENDING)
		do_signal(regs);
}

void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
{ 
	struct task_struct *me = current; 
	if (show_unhandled_signals && printk_ratelimit()) {
		printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
	       me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
		print_vma_addr(" in ", regs->ip);
		printk("\n");
	}

	force_sig(SIGSEGV, me); 
}
Commit	Line	Data
1da177e4	1	/*
1da177e4 LT	2	* Copyright (C) 1991, 1992 Linus Torvalds
	3	* Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs
	4	*
	5	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	6	* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
	7	* 2000-2002 x86-64 support by Andi Kleen
1da177e4 LT	8	*/
	9
	10	#include <linux/sched.h>
	11	#include <linux/mm.h>
	12	#include <linux/smp.h>
1da177e4 LT	13	#include <linux/kernel.h>
	14	#include <linux/signal.h>
	15	#include <linux/errno.h>
	16	#include <linux/wait.h>
	17	#include <linux/ptrace.h>
	18	#include <linux/unistd.h>
	19	#include <linux/stddef.h>
	20	#include <linux/personality.h>
	21	#include <linux/compiler.h>
1a176803	22	#include <asm/processor.h>
1da177e4 LT	23	#include <asm/ucontext.h>
	24	#include <asm/uaccess.h>
	25	#include <asm/i387.h>
	26	#include <asm/proto.h>
c5924b7d	27	#include <asm/ia32_unistd.h>
e02e68d3	28	#include <asm/mce.h>
bbc1f698	29	#include <asm/syscalls.h>
123a6347	30	#include "sigframe.h"
1da177e4	31
1da177e4 LT	32	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))
1da177e4 LT	33
1a176803 HH	34	#define __FIX_EFLAGS (X86_EFLAGS_AC \| X86_EFLAGS_OF \| \
	35	X86_EFLAGS_DF \| X86_EFLAGS_TF \| X86_EFLAGS_SF \| \
	36	X86_EFLAGS_ZF \| X86_EFLAGS_AF \| X86_EFLAGS_PF \| \
	37	X86_EFLAGS_CF)
	38
	39	#ifdef CONFIG_X86_32
	40	# define FIX_EFLAGS (__FIX_EFLAGS \| X86_EFLAGS_RF)
	41	#else
	42	# define FIX_EFLAGS __FIX_EFLAGS
	43	#endif
	44
0928d6ef	45	int ia32_setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4	46	sigset_t set, struct pt_regs regs);
0928d6ef	47	int ia32_setup_frame(int sig, struct k_sigaction *ka,
1da177e4 LT	48	sigset_t set, struct pt_regs regs);
1da177e4 LT	49
1da177e4 LT	50	asmlinkage long
	51	sys_sigaltstack(const stack_t __user uss, stack_t __user uoss,
	52	struct pt_regs *regs)
	53	{
65ea5b03	54	return do_sigaltstack(uss, uoss, regs->sp);
1da177e4 LT	55	}
1da177e4 LT	56
b30f3ae5 LT	57	/*
	58	* Signal frame handlers.
	59	*/
	60
	61	static inline int save_i387(struct _fpstate __user *buf)
	62	{
	63	struct task_struct *tsk = current;
	64	int err = 0;
	65
	66	BUILD_BUG_ON(sizeof(struct user_i387_struct) !=
	67	sizeof(tsk->thread.xstate->fxsave));
	68
	69	if ((unsigned long)buf % 16)
	70	printk("save_i387: bad fpstate %p\n", buf);
	71
	72	if (!used_math())
	73	return 0;
	74	clear_used_math(); /* trigger finit */
	75	if (task_thread_info(tsk)->status & TS_USEDFPU) {
	76	err = save_i387_checking((struct i387_fxsave_struct __user *)
	77	buf);
	78	if (err)
	79	return err;
	80	task_thread_info(tsk)->status &= ~TS_USEDFPU;
	81	stts();
	82	} else {
	83	if (__copy_to_user(buf, &tsk->thread.xstate->fxsave,
	84	sizeof(struct i387_fxsave_struct)))
	85	return -1;
	86	}
	87	return 1;
	88	}
	89
	90	/*
	91	* This restores directly out of user space. Exceptions are handled.
	92	*/
	93	static inline int restore_i387(struct _fpstate __user *buf)
	94	{
	95	struct task_struct *tsk = current;
	96	int err;
	97
	98	if (!used_math()) {
	99	err = init_fpu(tsk);
	100	if (err)
	101	return err;
	102	}
	103
	104	if (!(task_thread_info(current)->status & TS_USEDFPU)) {
	105	clts();
	106	task_thread_info(current)->status \|= TS_USEDFPU;
	107	}
6ffac1e9 SS	108	err = restore_fpu_checking((__force struct i387_fxsave_struct *)buf);
	109	if (unlikely(err)) {
	110	/*
	111	* Encountered an error while doing the restore from the
	112	* user buffer, clear the fpu state.
	113	*/
	114	clear_fpu(tsk);
	115	clear_used_math();
	116	}
	117	return err;
b30f3ae5	118	}
1da177e4 LT	119
	120	/*
	121	* Do a signal return; undo the signal stack.
	122	*/
1da177e4	123	static int
866bc13f HH	124	restore_sigcontext(struct pt_regs regs, struct sigcontext __user sc,
866bc13f HH	125	unsigned long *pax)
1da177e4 LT	126	{
	127	unsigned int err = 0;
	128
	129	/* Always make any pending restarted system calls return -EINTR */
	130	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	131
	132	#define COPY(x) err \|= __get_user(regs->x, &sc->x)
	133
742fa54a PA	134	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
742fa54a PA	135	COPY(dx); COPY(cx); COPY(ip);
1da177e4 LT	136	COPY(r8);
	137	COPY(r9);
	138	COPY(r10);
	139	COPY(r11);
	140	COPY(r12);
	141	COPY(r13);
	142	COPY(r14);
	143	COPY(r15);
	144
e4e5d324 BF	145	/* Kernel saves and restores only the CS segment register on signals,
	146	* which is the bare minimum needed to allow mixed 32/64-bit code.
	147	* App's signal handler can save/restore other segments if needed. */
	148	{
	149	unsigned cs;
	150	err \|= __get_user(cs, &sc->cs);
	151	regs->cs = cs \| 3; /* Force into user mode */
	152	}
	153
1da177e4 LT	154	{
1da177e4 LT	155	unsigned int tmpflags;
742fa54a	156	err \|= __get_user(tmpflags, &sc->flags);
1a176803	157	regs->flags = (regs->flags & ~FIX_EFLAGS) \| (tmpflags & FIX_EFLAGS);
65ea5b03	158	regs->orig_ax = -1; /* disable syscall checks */
1da177e4 LT	159	}
	160
	161	{
	162	struct _fpstate __user * buf;
	163	err \|= __get_user(buf, &sc->fpstate);
	164
	165	if (buf) {
	166	if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
	167	goto badframe;
	168	err \|= restore_i387(buf);
	169	} else {
	170	struct task_struct *me = current;
	171	if (used_math()) {
	172	clear_fpu(me);
	173	clear_used_math();
	174	}
	175	}
	176	}
	177
866bc13f	178	err \|= __get_user(*pax, &sc->ax);
1da177e4 LT	179	return err;
	180
	181	badframe:
	182	return 1;
	183	}
	184
	185	asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
	186	{
	187	struct rt_sigframe __user *frame;
	188	sigset_t set;
65ea5b03	189	unsigned long ax;
1da177e4	190
2d19c458 HH	191	frame = (struct rt_sigframe __user *)(regs->sp - sizeof(long));
2d19c458 HH	192	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
1da177e4	193	goto badframe;
2d19c458	194	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
1da177e4	195	goto badframe;
1da177e4 LT	196
	197	sigdelsetmask(&set, ~_BLOCKABLE);
	198	spin_lock_irq(&current->sighand->siglock);
	199	current->blocked = set;
	200	recalc_sigpending();
	201	spin_unlock_irq(&current->sighand->siglock);
	202
65ea5b03	203	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &ax))
1da177e4 LT	204	goto badframe;
1da177e4 LT	205
65ea5b03	206	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
1da177e4 LT	207	goto badframe;
1da177e4 LT	208
65ea5b03	209	return ax;
1da177e4 LT	210
	211	badframe:
	212	signal_fault(regs,frame,"sigreturn");
	213	return 0;
	214	}
	215
	216	/*
	217	* Set up a signal frame.
	218	*/
	219
	220	static inline int
	221	setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs, unsigned long mask, struct task_struct *me)
	222	{
	223	int err = 0;
1da177e4	224
e4e5d324	225	err \|= __put_user(regs->cs, &sc->cs);
1da177e4 LT	226	err \|= __put_user(0, &sc->gs);
	227	err \|= __put_user(0, &sc->fs);
	228
742fa54a PA	229	err \|= __put_user(regs->di, &sc->di);
	230	err \|= __put_user(regs->si, &sc->si);
	231	err \|= __put_user(regs->bp, &sc->bp);
	232	err \|= __put_user(regs->sp, &sc->sp);
	233	err \|= __put_user(regs->bx, &sc->bx);
	234	err \|= __put_user(regs->dx, &sc->dx);
	235	err \|= __put_user(regs->cx, &sc->cx);
	236	err \|= __put_user(regs->ax, &sc->ax);
1da177e4 LT	237	err \|= __put_user(regs->r8, &sc->r8);
	238	err \|= __put_user(regs->r9, &sc->r9);
	239	err \|= __put_user(regs->r10, &sc->r10);
	240	err \|= __put_user(regs->r11, &sc->r11);
	241	err \|= __put_user(regs->r12, &sc->r12);
	242	err \|= __put_user(regs->r13, &sc->r13);
	243	err \|= __put_user(regs->r14, &sc->r14);
	244	err \|= __put_user(regs->r15, &sc->r15);
	245	err \|= __put_user(me->thread.trap_no, &sc->trapno);
	246	err \|= __put_user(me->thread.error_code, &sc->err);
742fa54a PA	247	err \|= __put_user(regs->ip, &sc->ip);
742fa54a PA	248	err \|= __put_user(regs->flags, &sc->flags);
1da177e4 LT	249	err \|= __put_user(mask, &sc->oldmask);
	250	err \|= __put_user(me->thread.cr2, &sc->cr2);
	251
	252	return err;
	253	}
	254
	255	/*
	256	* Determine which stack to use..
	257	*/
	258
	259	static void __user *
	260	get_stack(struct k_sigaction ka, struct pt_regs regs, unsigned long size)
	261	{
65ea5b03	262	unsigned long sp;
1da177e4 LT	263
1da177e4 LT	264	/* Default to using normal stack - redzone*/
65ea5b03	265	sp = regs->sp - 128;
1da177e4 LT	266
1da177e4 LT	267	/* This is the X/Open sanctioned signal stack switching. */
1da177e4	268	if (ka->sa.sa_flags & SA_ONSTACK) {
65ea5b03 PA	269	if (sas_ss_flags(sp) == 0)
65ea5b03 PA	270	sp = current->sas_ss_sp + current->sas_ss_size;
1da177e4 LT	271	}
1da177e4 LT	272
65ea5b03	273	return (void __user *)round_down(sp - size, 16);
1da177e4 LT	274	}
1da177e4 LT	275
0928d6ef	276	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4 LT	277	sigset_t set, struct pt_regs regs)
	278	{
	279	struct rt_sigframe __user *frame;
	280	struct _fpstate __user *fp = NULL;
	281	int err = 0;
	282	struct task_struct *me = current;
	283
	284	if (used_math()) {
	285	fp = get_stack(ka, regs, sizeof(struct _fpstate));
	286	frame = (void __user *)round_down(
	287	(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
	288
	289	if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate)))
	290	goto give_sigsegv;
	291
	292	if (save_i387(fp) < 0)
	293	err \|= -1;
	294	} else
	295	frame = get_stack(ka, regs, sizeof(struct rt_sigframe)) - 8;
	296
	297	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	298	goto give_sigsegv;
	299
	300	if (ka->sa.sa_flags & SA_SIGINFO) {
	301	err \|= copy_siginfo_to_user(&frame->info, info);
	302	if (err)
	303	goto give_sigsegv;
	304	}
	305
	306	/* Create the ucontext. */
	307	err \|= __put_user(0, &frame->uc.uc_flags);
	308	err \|= __put_user(0, &frame->uc.uc_link);
	309	err \|= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
65ea5b03	310	err \|= __put_user(sas_ss_flags(regs->sp),
1da177e4 LT	311	&frame->uc.uc_stack.ss_flags);
	312	err \|= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
	313	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0], me);
	314	err \|= __put_user(fp, &frame->uc.uc_mcontext.fpstate);
	315	if (sizeof(*set) == 16) {
	316	__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
	317	__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
	318	} else
	319	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	320
	321	/* Set up to return from userspace. If provided, use a stub
	322	already in userspace. */
	323	/* x86-64 should always use SA_RESTORER. */
	324	if (ka->sa.sa_flags & SA_RESTORER) {
	325	err \|= __put_user(ka->sa.sa_restorer, &frame->pretcode);
	326	} else {
	327	/* could use a vstub here */
	328	goto give_sigsegv;
	329	}
	330
	331	if (err)
	332	goto give_sigsegv;
	333
1da177e4	334	/* Set up registers for signal handler */
65ea5b03	335	regs->di = sig;
1da177e4	336	/* In case the signal handler was declared without prototypes */
65ea5b03	337	regs->ax = 0;
1da177e4 LT	338
	339	/* This also works for non SA_SIGINFO handlers because they expect the
	340	next argument after the signal number on the stack. */
65ea5b03 PA	341	regs->si = (unsigned long)&frame->info;
	342	regs->dx = (unsigned long)&frame->uc;
	343	regs->ip = (unsigned long) ka->sa.sa_handler;
1da177e4	344
65ea5b03	345	regs->sp = (unsigned long)frame;
1da177e4	346
e4e5d324 BF	347	/* Set up the CS register to run signal handlers in 64-bit mode,
	348	even if the handler happens to be interrupting 32-bit code. */
	349	regs->cs = __USER_CS;
	350
1d001df1	351	return 0;
1da177e4 LT	352
	353	give_sigsegv:
	354	force_sigsegv(sig, current);
1d001df1	355	return -EFAULT;
1da177e4 LT	356	}
1da177e4 LT	357
40f0933d RM	358	/*
	359	* Return -1L or the syscall number that @regs is executing.
	360	*/
	361	static long current_syscall(struct pt_regs *regs)
	362	{
	363	/*
	364	* We always sign-extend a -1 value being set here,
	365	* so this is always either -1L or a syscall number.
	366	*/
	367	return regs->orig_ax;
	368	}
	369
	370	/*
	371	* Return a value that is -EFOO if the system call in @regs->orig_ax
	372	* returned an error. This only works for @regs from @current.
	373	*/
	374	static long current_syscall_ret(struct pt_regs *regs)
	375	{
	376	#ifdef CONFIG_IA32_EMULATION
	377	if (test_thread_flag(TIF_IA32))
	378	/*
	379	* Sign-extend the value so (int)-EFOO becomes (long)-EFOO
	380	* and will match correctly in comparisons.
	381	*/
	382	return (int) regs->ax;
	383	#endif
	384	return regs->ax;
	385	}
	386
1da177e4 LT	387	/*
	388	* OK, we're invoking a handler
	389	*/
	390
0928d6ef	391	static int
1da177e4	392	handle_signal(unsigned long sig, siginfo_t info, struct k_sigaction ka,
ac66f3fd	393	sigset_t oldset, struct pt_regs regs)
1da177e4	394	{
0928d6ef RM	395	int ret;
0928d6ef RM	396
1da177e4	397	/* Are we from a system call? */
40f0933d	398	if (current_syscall(regs) >= 0) {
1da177e4	399	/* If so, check system call restarting.. */
40f0933d	400	switch (current_syscall_ret(regs)) {
ac66f3fd HH	401	case -ERESTART_RESTARTBLOCK:
	402	case -ERESTARTNOHAND:
	403	regs->ax = -EINTR;
	404	break;
1da177e4	405
ac66f3fd HH	406	case -ERESTARTSYS:
	407	if (!(ka->sa.sa_flags & SA_RESTART)) {
	408	regs->ax = -EINTR;
1da177e4	409	break;
ac66f3fd HH	410	}
	411	/* fallthrough */
	412	case -ERESTARTNOINTR:
	413	regs->ax = regs->orig_ax;
	414	regs->ip -= 2;
	415	break;
1da177e4 LT	416	}
	417	}
	418
d61915da	419	/*
e1f28773 RM	420	* If TF is set due to a debugger (TIF_FORCED_TF), clear the TF
e1f28773 RM	421	* flag so that register information in the sigcontext is correct.
d61915da	422	*/
65ea5b03	423	if (unlikely(regs->flags & X86_EFLAGS_TF) &&
e1f28773	424	likely(test_and_clear_thread_flag(TIF_FORCED_TF)))
65ea5b03	425	regs->flags &= ~X86_EFLAGS_TF;
d61915da	426
1da177e4 LT	427	#ifdef CONFIG_IA32_EMULATION
	428	if (test_thread_flag(TIF_IA32)) {
	429	if (ka->sa.sa_flags & SA_SIGINFO)
0928d6ef	430	ret = ia32_setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	431	else
0928d6ef	432	ret = ia32_setup_frame(sig, ka, oldset, regs);
1da177e4 LT	433	} else
1da177e4 LT	434	#endif
0928d6ef	435	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	436
1d001df1	437	if (ret == 0) {
55928e37 RM	438	/*
	439	* This has nothing to do with segment registers,
	440	* despite the name. This magic affects uaccess.h
	441	* macros' behavior. Reset it to the normal setting.
	442	*/
	443	set_fs(USER_DS);
	444
8b9c5ff3 RM	445	/*
	446	* Clear the direction flag as per the ABI for function entry.
	447	*/
	448	regs->flags &= ~X86_EFLAGS_DF;
	449
	450	/*
	451	* Clear TF when entering the signal handler, but
	452	* notify any tracer that was single-stepping it.
	453	* The tracer may want to single-step inside the
	454	* handler too.
	455	*/
	456	regs->flags &= ~X86_EFLAGS_TF;
	457	if (test_thread_flag(TIF_SINGLESTEP))
	458	ptrace_notify(SIGTRAP);
	459
1da177e4 LT	460	spin_lock_irq(&current->sighand->siglock);
1da177e4 LT	461	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
69be8f18 SR	462	if (!(ka->sa.sa_flags & SA_NODEFER))
69be8f18 SR	463	sigaddset(&current->blocked,sig);
1da177e4 LT	464	recalc_sigpending();
	465	spin_unlock_irq(&current->sighand->siglock);
	466	}
0928d6ef RM	467
0928d6ef RM	468	return ret;
1da177e4 LT	469	}
	470
	471	/*
	472	* Note that 'init' is a special process: it doesn't get signals it doesn't
	473	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	474	* mistake.
	475	*/
1d001df1	476	static void do_signal(struct pt_regs *regs)
1da177e4 LT	477	{
	478	struct k_sigaction ka;
	479	siginfo_t info;
	480	int signr;
1d001df1	481	sigset_t *oldset;
1da177e4 LT	482
1da177e4 LT	483	/*
ac66f3fd HH	484	* We want the common case to go fast, which is why we may in certain
ac66f3fd HH	485	* cases get here from kernel mode. Just return without doing anything
1da177e4	486	* if so.
ac66f3fd HH	487	* X86_32: vm86 regs switched out by assembly code before reaching
ac66f3fd HH	488	* here, so testing against kernel CS suffices.
1da177e4	489	*/
76381fee	490	if (!user_mode(regs))
1d001df1	491	return;
1da177e4	492
5a8da0ea	493	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
1d001df1 AK	494	oldset = &current->saved_sigmask;
1d001df1 AK	495	else
1da177e4 LT	496	oldset = &current->blocked;
	497
	498	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	499	if (signr > 0) {
676b1855	500	/* Re-enable any watchpoints before delivering the
1da177e4 LT	501	* signal to user space. The processor register will
	502	* have been cleared if the watchpoint triggered
	503	* inside the kernel.
	504	*/
	505	if (current->thread.debugreg7)
e9129e56	506	set_debugreg(current->thread.debugreg7, 7);
1da177e4 LT	507
1da177e4 LT	508	/* Whee! Actually deliver the signal. */
1d001df1	509	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
5a8da0ea RM	510	/*
5a8da0ea RM	511	* A signal was successfully delivered; the saved
1d001df1 AK	512	* sigmask will have been stored in the signal frame,
1d001df1 AK	513	* and will be restored by sigreturn, so we can simply
5a8da0ea RM	514	* clear the TS_RESTORE_SIGMASK flag.
	515	*/
	516	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
1d001df1 AK	517	}
1d001df1 AK	518	return;
1da177e4 LT	519	}
1da177e4 LT	520
1da177e4	521	/* Did we come from a system call? */
40f0933d	522	if (current_syscall(regs) >= 0) {
1da177e4	523	/* Restart the system call - no handlers present */
40f0933d	524	switch (current_syscall_ret(regs)) {
1d001df1 AK	525	case -ERESTARTNOHAND:
	526	case -ERESTARTSYS:
	527	case -ERESTARTNOINTR:
65ea5b03 PA	528	regs->ax = regs->orig_ax;
65ea5b03 PA	529	regs->ip -= 2;
1d001df1 AK	530	break;
1d001df1 AK	531	case -ERESTART_RESTARTBLOCK:
65ea5b03	532	regs->ax = test_thread_flag(TIF_IA32) ?
607a1685 AK	533	__NR_ia32_restart_syscall :
607a1685 AK	534	__NR_restart_syscall;
65ea5b03	535	regs->ip -= 2;
1d001df1	536	break;
1da177e4 LT	537	}
1da177e4 LT	538	}
1d001df1	539
ac66f3fd HH	540	/*
	541	* If there's no signal to deliver, we just put the saved sigmask
	542	* back.
	543	*/
5a8da0ea RM	544	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
5a8da0ea RM	545	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
1d001df1 AK	546	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
1d001df1 AK	547	}
1da177e4 LT	548	}
1da177e4 LT	549
ac66f3fd HH	550	void do_notify_resume(struct pt_regs regs, void unused,
ac66f3fd HH	551	__u32 thread_info_flags)
1da177e4	552	{
e02e68d3 TH	553	#ifdef CONFIG_X86_MCE
	554	/* notify userspace of pending MCEs */
	555	if (thread_info_flags & _TIF_MCE_NOTIFY)
	556	mce_notify_user();
	557	#endif /* CONFIG_X86_MCE */
	558
1da177e4	559	/* deal with pending signal delivery */
5a8da0ea	560	if (thread_info_flags & _TIF_SIGPENDING)
1d001df1	561	do_signal(regs);
1da177e4 LT	562	}
	563
	564	void signal_fault(struct pt_regs regs, void __user frame, char *where)
	565	{
	566	struct task_struct *me = current;
03252919 AK	567	if (show_unhandled_signals && printk_ratelimit()) {
03252919 AK	568	printk("%s[%d] bad frame in %s frame:%p ip:%lx sp:%lx orax:%lx",
65ea5b03	569	me->comm,me->pid,where,frame,regs->ip,regs->sp,regs->orig_ax);
03252919 AK	570	print_vma_addr(" in ", regs->ip);
	571	printk("\n");
	572	}
1da177e4 LT	573
	574	force_sig(SIGSEGV, me);
	575	}