x86: signal: unify signal_{32|64}.c

Impact: cleanup

Unify signal_{32|64}.c! Mechanic unification - the two
files are the same.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 915 insertions, 0 deletions

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
new file mode 100644
index 00000000000..b1f4d34e0a3
--- /dev/null
+++ b/arch/x86/kernel/signal.c
@@ -0,0 +1,915 @@
+/*
+ *  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/tracehook.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/personality.h>
+#include <linux/uaccess.h>
+
+#include <asm/processor.h>
+#include <asm/ucontext.h>
+#include <asm/i387.h>
+#include <asm/vdso.h>
+
+#ifdef CONFIG_X86_64
+#include <asm/proto.h>
+#include <asm/ia32_unistd.h>
+#include <asm/mce.h>
+#endif /* CONFIG_X86_64 */
+
+#include <asm/syscall.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
+
+#define COPY(x)			{		\
+	err |= __get_user(regs->x, &sc->x);	\
+}
+
+#define COPY_SEG(seg)		{			\
+		unsigned short tmp;			\
+		err |= __get_user(tmp, &sc->seg);	\
+		regs->seg = tmp;			\
+}
+
+#define COPY_SEG_CPL3(seg)	{			\
+		unsigned short tmp;			\
+		err |= __get_user(tmp, &sc->seg);	\
+		regs->seg = tmp | 3;			\
+}
+
+#define GET_SEG(seg)		{			\
+		unsigned short tmp;			\
+		err |= __get_user(tmp, &sc->seg);	\
+		loadsegment(seg, tmp);			\
+}
+
+static int
+restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
+		   unsigned long *pax)
+{
+	void __user *buf;
+	unsigned int tmpflags;
+	unsigned int err = 0;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+#ifdef CONFIG_X86_32
+	GET_SEG(gs);
+	COPY_SEG(fs);
+	COPY_SEG(es);
+	COPY_SEG(ds);
+#endif /* CONFIG_X86_32 */
+
+	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
+	COPY(dx); COPY(cx); COPY(ip);
+
+#ifdef CONFIG_X86_64
+	COPY(r8);
+	COPY(r9);
+	COPY(r10);
+	COPY(r11);
+	COPY(r12);
+	COPY(r13);
+	COPY(r14);
+	COPY(r15);
+#endif /* CONFIG_X86_64 */
+
+#ifdef CONFIG_X86_32
+	COPY_SEG_CPL3(cs);
+	COPY_SEG_CPL3(ss);
+#else /* !CONFIG_X86_32 */
+	/* 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. */
+	COPY_SEG_CPL3(cs);
+#endif /* CONFIG_X86_32 */
+
+	err |= __get_user(tmpflags, &sc->flags);
+	regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
+	regs->orig_ax = -1;		/* disable syscall checks */
+
+	err |= __get_user(buf, &sc->fpstate);
+	err |= restore_i387_xstate(buf);
+
+	err |= __get_user(*pax, &sc->ax);
+	return err;
+}
+
+static int
+setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
+		 struct pt_regs *regs, unsigned long mask)
+{
+	int err = 0;
+
+#ifdef CONFIG_X86_32
+	{
+		unsigned int tmp;
+
+		savesegment(gs, tmp);
+		err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
+	}
+	err |= __put_user(regs->fs, (unsigned int __user *)&sc->fs);
+	err |= __put_user(regs->es, (unsigned int __user *)&sc->es);
+	err |= __put_user(regs->ds, (unsigned int __user *)&sc->ds);
+#endif /* CONFIG_X86_32 */
+
+	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);
+#ifdef CONFIG_X86_64
+	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);
+#endif /* CONFIG_X86_64 */
+
+	err |= __put_user(current->thread.trap_no, &sc->trapno);
+	err |= __put_user(current->thread.error_code, &sc->err);
+	err |= __put_user(regs->ip, &sc->ip);
+#ifdef CONFIG_X86_32
+	err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
+	err |= __put_user(regs->flags, &sc->flags);
+	err |= __put_user(regs->sp, &sc->sp_at_signal);
+	err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
+#else /* !CONFIG_X86_32 */
+	err |= __put_user(regs->flags, &sc->flags);
+	err |= __put_user(regs->cs, &sc->cs);
+	err |= __put_user(0, &sc->gs);
+	err |= __put_user(0, &sc->fs);
+#endif /* CONFIG_X86_32 */
+
+	err |= __put_user(fpstate, &sc->fpstate);
+
+	/* non-iBCS2 extensions.. */
+	err |= __put_user(mask, &sc->oldmask);
+	err |= __put_user(current->thread.cr2, &sc->cr2);
+
+	return err;
+}
+
+/*
+ * Set up a signal frame.
+ */
+#ifdef CONFIG_X86_32
+static const struct {
+	u16 poplmovl;
+	u32 val;
+	u16 int80;
+} __attribute__((packed)) retcode = {
+	0xb858,		/* popl %eax; movl $..., %eax */
+	__NR_sigreturn,
+	0x80cd,		/* int $0x80 */
+};
+
+static const struct {
+	u8  movl;
+	u32 val;
+	u16 int80;
+	u8  pad;
+} __attribute__((packed)) rt_retcode = {
+	0xb8,		/* movl $..., %eax */
+	__NR_rt_sigreturn,
+	0x80cd,		/* int $0x80 */
+	0
+};
+
+/*
+ * Determine which stack to use..
+ */
+static inline void __user *
+get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
+	     void **fpstate)
+{
+	unsigned long sp;
+
+	/* Default to using normal stack */
+	sp = regs->sp;
+
+	/*
+	 * If we are on the alternate signal stack and would overflow it, don't.
+	 * Return an always-bogus address instead so we will die with SIGSEGV.
+	 */
+	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
+		return (void __user *) -1L;
+
+	/* 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;
+	} else {
+		/* This is the legacy signal stack switching. */
+		if ((regs->ss & 0xffff) != __USER_DS &&
+			!(ka->sa.sa_flags & SA_RESTORER) &&
+				ka->sa.sa_restorer)
+			sp = (unsigned long) ka->sa.sa_restorer;
+	}
+
+	if (used_math()) {
+		sp = sp - sig_xstate_size;
+		*fpstate = (struct _fpstate *) sp;
+		if (save_i387_xstate(*fpstate) < 0)
+			return (void __user *)-1L;
+	}
+
+	sp -= frame_size;
+	/*
+	 * Align the stack pointer according to the i386 ABI,
+	 * i.e. so that on function entry ((sp + 4) & 15) == 0.
+	 */
+	sp = ((sp + 4) & -16ul) - 4;
+
+	return (void __user *) sp;
+}
+
+static int
+__setup_frame(int sig, struct k_sigaction *ka, sigset_t *set,
+	      struct pt_regs *regs)
+{
+	struct sigframe __user *frame;
+	void __user *restorer;
+	int err = 0;
+	void __user *fpstate = NULL;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		return -EFAULT;
+
+	if (__put_user(sig, &frame->sig))
+		return -EFAULT;
+
+	if (setup_sigcontext(&frame->sc, fpstate, regs, set->sig[0]))
+		return -EFAULT;
+
+	if (_NSIG_WORDS > 1) {
+		if (__copy_to_user(&frame->extramask, &set->sig[1],
+				   sizeof(frame->extramask)))
+			return -EFAULT;
+	}
+
+	if (current->mm->context.vdso)
+		restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
+	else
+		restorer = &frame->retcode;
+	if (ka->sa.sa_flags & SA_RESTORER)
+		restorer = ka->sa.sa_restorer;
+
+	/* Set up to return from userspace.  */
+	err |= __put_user(restorer, &frame->pretcode);
+
+	/*
+	 * This is popl %eax ; movl $__NR_sigreturn, %eax ; int $0x80
+	 *
+	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
+	 * reasons and because gdb uses it as a signature to notice
+	 * signal handler stack frames.
+	 */
+	err |= __put_user(*((u64 *)&retcode), (u64 *)frame->retcode);
+
+	if (err)
+		return -EFAULT;
+
+	/* Set up registers for signal handler */
+	regs->sp = (unsigned long)frame;
+	regs->ip = (unsigned long)ka->sa.sa_handler;
+	regs->ax = (unsigned long)sig;
+	regs->dx = 0;
+	regs->cx = 0;
+
+	regs->ds = __USER_DS;
+	regs->es = __USER_DS;
+	regs->ss = __USER_DS;
+	regs->cs = __USER_CS;
+
+	return 0;
+}
+
+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;
+	void __user *restorer;
+	int err = 0;
+	void __user *fpstate = NULL;
+
+	frame = get_sigframe(ka, regs, sizeof(*frame), &fpstate);
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		return -EFAULT;
+
+	err |= __put_user(sig, &frame->sig);
+	err |= __put_user(&frame->info, &frame->pinfo);
+	err |= __put_user(&frame->uc, &frame->puc);
+	err |= copy_siginfo_to_user(&frame->info, info);
+	if (err)
+		return -EFAULT;
+
+	/* Create the ucontext.  */
+	if (cpu_has_xsave)
+		err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
+	else
+		err |= __put_user(0, &frame->uc.uc_flags);
+	err |= __put_user(0, &frame->uc.uc_link);
+	err |= __put_user(current->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(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+	err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+				regs, set->sig[0]);
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+	if (err)
+		return -EFAULT;
+
+	/* Set up to return from userspace.  */
+	restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
+	if (ka->sa.sa_flags & SA_RESTORER)
+		restorer = ka->sa.sa_restorer;
+	err |= __put_user(restorer, &frame->pretcode);
+
+	/*
+	 * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
+	 *
+	 * WE DO NOT USE IT ANY MORE! It's only left here for historical
+	 * reasons and because gdb uses it as a signature to notice
+	 * signal handler stack frames.
+	 */
+	err |= __put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
+
+	if (err)
+		return -EFAULT;
+
+	/* Set up registers for signal handler */
+	regs->sp = (unsigned long)frame;
+	regs->ip = (unsigned long)ka->sa.sa_handler;
+	regs->ax = (unsigned long)sig;
+	regs->dx = (unsigned long)&frame->info;
+	regs->cx = (unsigned long)&frame->uc;
+
+	regs->ds = __USER_DS;
+	regs->es = __USER_DS;
+	regs->ss = __USER_DS;
+	regs->cs = __USER_CS;
+
+	return 0;
+}
+#else /* !CONFIG_X86_32 */
+/*
+ * Determine which stack to use..
+ */
+static void __user *
+get_stack(struct k_sigaction *ka, unsigned long sp, unsigned long size)
+{
+	/* Default to using normal stack - redzone*/
+	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, 64);
+}
+
+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;
+	void __user *fp = NULL;
+	int err = 0;
+	struct task_struct *me = current;
+
+	if (used_math()) {
+		fp = get_stack(ka, regs->sp, sig_xstate_size);
+		frame = (void __user *)round_down(
+			(unsigned long)fp - sizeof(struct rt_sigframe), 16) - 8;
+
+		if (save_i387_xstate(fp) < 0)
+			return -EFAULT;
+	} else
+		frame = get_stack(ka, regs->sp, sizeof(struct rt_sigframe)) - 8;
+
+	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+		return -EFAULT;
+
+	if (ka->sa.sa_flags & SA_SIGINFO) {
+		if (copy_siginfo_to_user(&frame->info, info))
+			return -EFAULT;
+	}
+
+	/* Create the ucontext.  */
+	if (cpu_has_xsave)
+		err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
+	else
+		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, fp, regs, set->sig[0]);
+	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 */
+		return -EFAULT;
+	}
+
+	if (err)
+		return -EFAULT;
+
+	/* 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;
+}
+#endif /* CONFIG_X86_32 */
+
+#ifdef CONFIG_X86_32
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+asmlinkage int
+sys_sigsuspend(int history0, int history1, old_sigset_t mask)
+{
+	mask &= _BLOCKABLE;
+	spin_lock_irq(&current->sighand->siglock);
+	current->saved_sigmask = current->blocked;
+	siginitset(&current->blocked, mask);
+	recalc_sigpending();
+	spin_unlock_irq(&current->sighand->siglock);
+
+	current->state = TASK_INTERRUPTIBLE;
+	schedule();
+	set_restore_sigmask();
+
+	return -ERESTARTNOHAND;
+}
+
+asmlinkage int
+sys_sigaction(int sig, const struct old_sigaction __user *act,
+	      struct old_sigaction __user *oact)
+{
+	struct k_sigaction new_ka, old_ka;
+	int ret;
+
+	if (act) {
+		old_sigset_t mask;
+
+		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
+		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
+		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
+			return -EFAULT;
+
+		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
+		__get_user(mask, &act->sa_mask);
+		siginitset(&new_ka.sa.sa_mask, mask);
+	}
+
+	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+
+	if (!ret && oact) {
+		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
+		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
+		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
+			return -EFAULT;
+
+		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
+	}
+
+	return ret;
+}
+#endif /* CONFIG_X86_32 */
+
+#ifdef CONFIG_X86_32
+asmlinkage int sys_sigaltstack(unsigned long bx)
+{
+	/*
+	 * This is needed to make gcc realize it doesn't own the
+	 * "struct pt_regs"
+	 */
+	struct pt_regs *regs = (struct pt_regs *)&bx;
+	const stack_t __user *uss = (const stack_t __user *)bx;
+	stack_t __user *uoss = (stack_t __user *)regs->cx;
+
+	return do_sigaltstack(uss, uoss, regs->sp);
+}
+#else /* !CONFIG_X86_32 */
+asmlinkage long
+sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
+		struct pt_regs *regs)
+{
+	return do_sigaltstack(uss, uoss, regs->sp);
+}
+#endif /* CONFIG_X86_32 */
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+#ifdef CONFIG_X86_32
+asmlinkage unsigned long sys_sigreturn(unsigned long __unused)
+{
+	struct sigframe __user *frame;
+	struct pt_regs *regs;
+	unsigned long ax;
+	sigset_t set;
+
+	regs = (struct pt_regs *) &__unused;
+	frame = (struct sigframe __user *)(regs->sp - 8);
+
+	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+		goto badframe;
+	if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1
+		&& __copy_from_user(&set.sig[1], &frame->extramask,
+				    sizeof(frame->extramask))))
+		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->sc, &ax))
+		goto badframe;
+	return ax;
+
+badframe:
+	if (show_unhandled_signals && printk_ratelimit()) {
+		printk("%s%s[%d] bad frame in sigreturn frame:"
+			"%p ip:%lx sp:%lx oeax:%lx",
+		    task_pid_nr(current) > 1 ? KERN_INFO : KERN_EMERG,
+		    current->comm, task_pid_nr(current), frame, regs->ip,
+		    regs->sp, regs->orig_ax);
+		print_vma_addr(" in ", regs->ip);
+		printk(KERN_CONT "\n");
+	}
+
+	force_sig(SIGSEGV, current);
+
+	return 0;
+}
+#endif /* CONFIG_X86_32 */
+
+static long do_rt_sigreturn(struct pt_regs *regs)
+{
+	struct rt_sigframe __user *frame;
+	unsigned long ax;
+	sigset_t set;
+
+	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, "rt_sigreturn");
+	return 0;
+}
+
+#ifdef CONFIG_X86_32
+asmlinkage int sys_rt_sigreturn(unsigned long __unused)
+{
+	struct pt_regs *regs = (struct pt_regs *)&__unused;
+
+	return do_rt_sigreturn(regs);
+}
+#else /* !CONFIG_X86_32 */
+asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
+{
+	return do_rt_sigreturn(regs);
+}
+#endif /* CONFIG_X86_32 */
+
+/*
+ * OK, we're invoking a handler:
+ */
+static int signr_convert(int sig)
+{
+#ifdef CONFIG_X86_32
+	struct thread_info *info = current_thread_info();
+
+	if (info->exec_domain && info->exec_domain->signal_invmap && sig < 32)
+		return info->exec_domain->signal_invmap[sig];
+#endif /* CONFIG_X86_32 */
+	return sig;
+}
+
+#ifdef CONFIG_X86_32
+
+#define is_ia32	1
+#define ia32_setup_frame	__setup_frame
+#define ia32_setup_rt_frame	__setup_rt_frame
+
+#else /* !CONFIG_X86_32 */
+
+#ifdef CONFIG_IA32_EMULATION
+#define is_ia32	test_thread_flag(TIF_IA32)
+#else /* !CONFIG_IA32_EMULATION */
+#define is_ia32	0
+#endif /* CONFIG_IA32_EMULATION */
+
+#endif /* CONFIG_X86_32 */
+
+static int
+setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+	       sigset_t *set, struct pt_regs *regs)
+{
+	int usig = signr_convert(sig);
+	int ret;
+
+	/* Set up the stack frame */
+	if (is_ia32) {
+		if (ka->sa.sa_flags & SA_SIGINFO)
+			ret = ia32_setup_rt_frame(usig, ka, info, set, regs);
+		else
+			ret = ia32_setup_frame(usig, ka, set, regs);
+	} else
+		ret = __setup_rt_frame(sig, ka, info, set, regs);
+
+	if (ret) {
+		force_sigsegv(sig, current);
+		return -EFAULT;
+	}
+
+	return ret;
+}
+
+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 (syscall_get_nr(current, regs) >= 0) {
+		/* If so, check system call restarting.. */
+		switch (syscall_get_error(current, 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;
+
+	ret = setup_rt_frame(sig, ka, info, oldset, regs);
+
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_X86_64
+	/*
+	 * 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);
+#endif
+
+	/*
+	 * 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;
+
+	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);
+
+	tracehook_signal_handler(sig, info, ka, regs,
+				 test_thread_flag(TIF_SINGLESTEP));
+
+	return 0;
+}
+
+#ifdef CONFIG_X86_32
+#define NR_restart_syscall	__NR_restart_syscall
+#else /* !CONFIG_X86_32 */
+#define NR_restart_syscall	\
+	test_thread_flag(TIF_IA32) ? __NR_ia32_restart_syscall : __NR_restart_syscall
+#endif /* CONFIG_X86_32 */
+
+/*
+ * 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 (syscall_get_nr(current, regs) >= 0) {
+		/* Restart the system call - no handlers present */
+		switch (syscall_get_error(current, regs)) {
+		case -ERESTARTNOHAND:
+		case -ERESTARTSYS:
+		case -ERESTARTNOINTR:
+			regs->ax = regs->orig_ax;
+			regs->ip -= 2;
+			break;
+
+		case -ERESTART_RESTARTBLOCK:
+			regs->ax = 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);
+	}
+}
+
+/*
+ * notification of userspace execution resumption
+ * - triggered by the TIF_WORK_MASK flags
+ */
+void
+do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags)
+{
+#if defined(CONFIG_X86_64) && defined(CONFIG_X86_MCE)
+	/* notify userspace of pending MCEs */
+	if (thread_info_flags & _TIF_MCE_NOTIFY)
+		mce_notify_user();
+#endif /* CONFIG_X86_64 && CONFIG_X86_MCE */
+
+	/* deal with pending signal delivery */
+	if (thread_info_flags & _TIF_SIGPENDING)
+		do_signal(regs);
+
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+		clear_thread_flag(TIF_NOTIFY_RESUME);
+		tracehook_notify_resume(regs);
+	}
+
+#ifdef CONFIG_X86_32
+	clear_thread_flag(TIF_IRET);
+#endif /* CONFIG_X86_32 */
+}
+
+void signal_fault(struct pt_regs *regs, void __user *frame, char *where)
+{
+	struct task_struct *me = current;
+
+	if (show_unhandled_signals && printk_ratelimit()) {
+		printk(KERN_INFO
+		       "%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(KERN_CONT "\n");
+	}
+
+	force_sig(SIGSEGV, me);
+}