1 files changed, 583 insertions, 0 deletions

diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c
new file mode 100644
index 0000000000..263e1d08f2
--- /dev/null
+++ b/arch/x86/um/signal.c
@@ -0,0 +1,583 @@
+/*
+ * Copyright (C) 2003 PathScale, Inc.
+ * Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+
+#include <linux/personality.h>
+#include <linux/ptrace.h>
+#include <linux/kernel.h>
+#include <asm/unistd.h>
+#include <linux/uaccess.h>
+#include <asm/ucontext.h>
+#include <frame_kern.h>
+#include <registers.h>
+#include <skas.h>
+
+#ifdef CONFIG_X86_32
+
+/*
+ * FPU tag word conversions.
+ */
+
+static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
+{
+	unsigned int tmp; /* to avoid 16 bit prefixes in the code */
+
+	/* Transform each pair of bits into 01 (valid) or 00 (empty) */
+	tmp = ~twd;
+	tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
+	/* and move the valid bits to the lower byte. */
+	tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
+	tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
+	tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
+	return tmp;
+}
+
+static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
+{
+	struct _fpxreg *st = NULL;
+	unsigned long twd = (unsigned long) fxsave->twd;
+	unsigned long tag;
+	unsigned long ret = 0xffff0000;
+	int i;
+
+#define FPREG_ADDR(f, n)	((char *)&(f)->st_space + (n) * 16)
+
+	for (i = 0; i < 8; i++) {
+		if (twd & 0x1) {
+			st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);
+
+			switch (st->exponent & 0x7fff) {
+			case 0x7fff:
+				tag = 2;		/* Special */
+				break;
+			case 0x0000:
+				if ( !st->significand[0] &&
+				     !st->significand[1] &&
+				     !st->significand[2] &&
+				     !st->significand[3] ) {
+					tag = 1;	/* Zero */
+				} else {
+					tag = 2;	/* Special */
+				}
+				break;
+			default:
+				if (st->significand[3] & 0x8000) {
+					tag = 0;	/* Valid */
+				} else {
+					tag = 2;	/* Special */
+				}
+				break;
+			}
+		} else {
+			tag = 3;			/* Empty */
+		}
+		ret |= (tag << (2 * i));
+		twd = twd >> 1;
+	}
+	return ret;
+}
+
+static int convert_fxsr_to_user(struct _fpstate __user *buf,
+				struct user_fxsr_struct *fxsave)
+{
+	unsigned long env[7];
+	struct _fpreg __user *to;
+	struct _fpxreg *from;
+	int i;
+
+	env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
+	env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
+	env[2] = twd_fxsr_to_i387(fxsave);
+	env[3] = fxsave->fip;
+	env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
+	env[5] = fxsave->foo;
+	env[6] = fxsave->fos;
+
+	if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
+		return 1;
+
+	to = &buf->_st[0];
+	from = (struct _fpxreg *) &fxsave->st_space[0];
+	for (i = 0; i < 8; i++, to++, from++) {
+		unsigned long __user *t = (unsigned long __user *)to;
+		unsigned long *f = (unsigned long *)from;
+
+		if (__put_user(*f, t) ||
+				__put_user(*(f + 1), t + 1) ||
+				__put_user(from->exponent, &to->exponent))
+			return 1;
+	}
+	return 0;
+}
+
+static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave,
+				  struct _fpstate __user *buf)
+{
+	unsigned long env[7];
+	struct _fpxreg *to;
+	struct _fpreg __user *from;
+	int i;
+
+	if (copy_from_user( env, buf, 7 * sizeof(long)))
+		return 1;
+
+	fxsave->cwd = (unsigned short)(env[0] & 0xffff);
+	fxsave->swd = (unsigned short)(env[1] & 0xffff);
+	fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
+	fxsave->fip = env[3];
+	fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
+	fxsave->fcs = (env[4] & 0xffff);
+	fxsave->foo = env[5];
+	fxsave->fos = env[6];
+
+	to = (struct _fpxreg *) &fxsave->st_space[0];
+	from = &buf->_st[0];
+	for (i = 0; i < 8; i++, to++, from++) {
+		unsigned long *t = (unsigned long *)to;
+		unsigned long __user *f = (unsigned long __user *)from;
+
+		if (__get_user(*t, f) ||
+		    __get_user(*(t + 1), f + 1) ||
+		    __get_user(to->exponent, &from->exponent))
+			return 1;
+	}
+	return 0;
+}
+
+extern int have_fpx_regs;
+
+#endif
+
+static int copy_sc_from_user(struct pt_regs *regs,
+			     struct sigcontext __user *from)
+{
+	struct sigcontext sc;
+	int err, pid;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	err = copy_from_user(&sc, from, sizeof(sc));
+	if (err)
+		return err;
+
+#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
+
+#ifdef CONFIG_X86_32
+	GETREG(GS, gs);
+	GETREG(FS, fs);
+	GETREG(ES, es);
+	GETREG(DS, ds);
+#endif
+	GETREG(DI, di);
+	GETREG(SI, si);
+	GETREG(BP, bp);
+	GETREG(SP, sp);
+	GETREG(BX, bx);
+	GETREG(DX, dx);
+	GETREG(CX, cx);
+	GETREG(AX, ax);
+	GETREG(IP, ip);
+
+#ifdef CONFIG_X86_64
+	GETREG(R8, r8);
+	GETREG(R9, r9);
+	GETREG(R10, r10);
+	GETREG(R11, r11);
+	GETREG(R12, r12);
+	GETREG(R13, r13);
+	GETREG(R14, r14);
+	GETREG(R15, r15);
+#endif
+
+	GETREG(CS, cs);
+	GETREG(EFLAGS, flags);
+#ifdef CONFIG_X86_32
+	GETREG(SS, ss);
+#endif
+
+#undef GETREG
+
+	pid = userspace_pid[current_thread_info()->cpu];
+#ifdef CONFIG_X86_32
+	if (have_fpx_regs) {
+		struct user_fxsr_struct fpx;
+
+		err = copy_from_user(&fpx,
+			&((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0],
+				     sizeof(struct user_fxsr_struct));
+		if (err)
+			return 1;
+
+		err = convert_fxsr_from_user(&fpx, (void *)sc.fpstate);
+		if (err)
+			return 1;
+
+		err = restore_fpx_registers(pid, (unsigned long *) &fpx);
+		if (err < 0) {
+			printk(KERN_ERR "copy_sc_from_user - "
+			       "restore_fpx_registers failed, errno = %d\n",
+			       -err);
+			return 1;
+		}
+	} else
+#endif
+	{
+		err = copy_from_user(regs->regs.fp, (void *)sc.fpstate,
+				     sizeof(struct _xstate));
+		if (err)
+			return 1;
+	}
+	return 0;
+}
+
+static int copy_sc_to_user(struct sigcontext __user *to,
+			   struct _xstate __user *to_fp, struct pt_regs *regs,
+			   unsigned long mask)
+{
+	struct sigcontext sc;
+	struct faultinfo * fi = &current->thread.arch.faultinfo;
+	int err, pid;
+	memset(&sc, 0, sizeof(struct sigcontext));
+
+#define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
+
+#ifdef CONFIG_X86_32
+	PUTREG(GS, gs);
+	PUTREG(FS, fs);
+	PUTREG(ES, es);
+	PUTREG(DS, ds);
+#endif
+	PUTREG(DI, di);
+	PUTREG(SI, si);
+	PUTREG(BP, bp);
+	PUTREG(SP, sp);
+	PUTREG(BX, bx);
+	PUTREG(DX, dx);
+	PUTREG(CX, cx);
+	PUTREG(AX, ax);
+#ifdef CONFIG_X86_64
+	PUTREG(R8, r8);
+	PUTREG(R9, r9);
+	PUTREG(R10, r10);
+	PUTREG(R11, r11);
+	PUTREG(R12, r12);
+	PUTREG(R13, r13);
+	PUTREG(R14, r14);
+	PUTREG(R15, r15);
+#endif
+
+	sc.cr2 = fi->cr2;
+	sc.err = fi->error_code;
+	sc.trapno = fi->trap_no;
+	PUTREG(IP, ip);
+	PUTREG(CS, cs);
+	PUTREG(EFLAGS, flags);
+#ifdef CONFIG_X86_32
+	PUTREG(SP, sp_at_signal);
+	PUTREG(SS, ss);
+#endif
+#undef PUTREG
+	sc.oldmask = mask;
+	sc.fpstate = (unsigned long)to_fp;
+
+	err = copy_to_user(to, &sc, sizeof(struct sigcontext));
+	if (err)
+		return 1;
+
+	pid = userspace_pid[current_thread_info()->cpu];
+
+#ifdef CONFIG_X86_32
+	if (have_fpx_regs) {
+		struct user_fxsr_struct fpx;
+
+		err = save_fpx_registers(pid, (unsigned long *) &fpx);
+		if (err < 0){
+			printk(KERN_ERR "copy_sc_to_user - save_fpx_registers "
+			       "failed, errno = %d\n", err);
+			return 1;
+		}
+
+		err = convert_fxsr_to_user(&to_fp->fpstate, &fpx);
+		if (err)
+			return 1;
+
+		err |= __put_user(fpx.swd, &to_fp->fpstate.status);
+		err |= __put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic);
+		if (err)
+			return 1;
+
+		if (copy_to_user(&to_fp->fpstate._fxsr_env[0], &fpx,
+				 sizeof(struct user_fxsr_struct)))
+			return 1;
+	} else
+#endif
+	{
+		if (copy_to_user(to_fp, regs->regs.fp, sizeof(struct _xstate)))
+			return 1;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_X86_32
+static int copy_ucontext_to_user(struct ucontext __user *uc,
+				 struct _xstate __user *fp, sigset_t *set,
+				 unsigned long sp)
+{
+	int err = 0;
+
+	err |= __save_altstack(&uc->uc_stack, sp);
+	err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, 0);
+	err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
+	return err;
+}
+
+struct sigframe
+{
+	char __user *pretcode;
+	int sig;
+	struct sigcontext sc;
+	struct _xstate fpstate;
+	unsigned long extramask[_NSIG_WORDS-1];
+	char retcode[8];
+};
+
+struct rt_sigframe
+{
+	char __user *pretcode;
+	int sig;
+	struct siginfo __user *pinfo;
+	void __user *puc;
+	struct siginfo info;
+	struct ucontext uc;
+	struct _xstate fpstate;
+	char retcode[8];
+};
+
+int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
+			  struct pt_regs *regs, sigset_t *mask)
+{
+	struct sigframe __user *frame;
+	void __user *restorer;
+	int err = 0, sig = ksig->sig;
+
+	/* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */
+	stack_top = ((stack_top + 4) & -16UL) - 4;
+	frame = (struct sigframe __user *) stack_top - 1;
+	if (!access_ok(frame, sizeof(*frame)))
+		return 1;
+
+	restorer = frame->retcode;
+	if (ksig->ka.sa.sa_flags & SA_RESTORER)
+		restorer = ksig->ka.sa.sa_restorer;
+
+	err |= __put_user(restorer, &frame->pretcode);
+	err |= __put_user(sig, &frame->sig);
+	err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]);
+	if (_NSIG_WORDS > 1)
+		err |= __copy_to_user(&frame->extramask, &mask->sig[1],
+				      sizeof(frame->extramask));
+
+	/*
+	 * This is popl %eax ; movl $,%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(0xb858, (short __user *)(frame->retcode+0));
+	err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2));
+	err |= __put_user(0x80cd, (short __user *)(frame->retcode+6));
+
+	if (err)
+		return err;
+
+	PT_REGS_SP(regs) = (unsigned long) frame;
+	PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
+	PT_REGS_AX(regs) = (unsigned long) sig;
+	PT_REGS_DX(regs) = (unsigned long) 0;
+	PT_REGS_CX(regs) = (unsigned long) 0;
+	return 0;
+}
+
+int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
+			  struct pt_regs *regs, sigset_t *mask)
+{
+	struct rt_sigframe __user *frame;
+	void __user *restorer;
+	int err = 0, sig = ksig->sig;
+
+	stack_top &= -8UL;
+	frame = (struct rt_sigframe __user *) stack_top - 1;
+	if (!access_ok(frame, sizeof(*frame)))
+		return 1;
+
+	restorer = frame->retcode;
+	if (ksig->ka.sa.sa_flags & SA_RESTORER)
+		restorer = ksig->ka.sa.sa_restorer;
+
+	err |= __put_user(restorer, &frame->pretcode);
+	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, &ksig->info);
+	err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
+					PT_REGS_SP(regs));
+
+	/*
+	 * This is movl $,%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(0xb8, (char __user *)(frame->retcode+0));
+	err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1));
+	err |= __put_user(0x80cd, (short __user *)(frame->retcode+5));
+
+	if (err)
+		return err;
+
+	PT_REGS_SP(regs) = (unsigned long) frame;
+	PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
+	PT_REGS_AX(regs) = (unsigned long) sig;
+	PT_REGS_DX(regs) = (unsigned long) &frame->info;
+	PT_REGS_CX(regs) = (unsigned long) &frame->uc;
+	return 0;
+}
+
+long sys_sigreturn(void)
+{
+	unsigned long sp = PT_REGS_SP(&current->thread.regs);
+	struct sigframe __user *frame = (struct sigframe __user *)(sp - 8);
+	sigset_t set;
+	struct sigcontext __user *sc = &frame->sc;
+	int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
+
+	if (copy_from_user(&set.sig[0], &sc->oldmask, sizeof(set.sig[0])) ||
+	    copy_from_user(&set.sig[1], frame->extramask, sig_size))
+		goto segfault;
+
+	set_current_blocked(&set);
+
+	if (copy_sc_from_user(&current->thread.regs, sc))
+		goto segfault;
+
+	/* Avoid ERESTART handling */
+	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
+	return PT_REGS_SYSCALL_RET(&current->thread.regs);
+
+ segfault:
+	force_sig(SIGSEGV);
+	return 0;
+}
+
+#else
+
+struct rt_sigframe
+{
+	char __user *pretcode;
+	struct ucontext uc;
+	struct siginfo info;
+	struct _xstate fpstate;
+};
+
+int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
+			  struct pt_regs *regs, sigset_t *set)
+{
+	struct rt_sigframe __user *frame;
+	int err = 0, sig = ksig->sig;
+	unsigned long fp_to;
+
+	frame = (struct rt_sigframe __user *)
+		round_down(stack_top - sizeof(struct rt_sigframe), 16);
+	/* Subtract 128 for a red zone and 8 for proper alignment */
+	frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
+
+	if (!access_ok(frame, sizeof(*frame)))
+		goto out;
+
+	if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
+		err |= copy_siginfo_to_user(&frame->info, &ksig->info);
+		if (err)
+			goto out;
+	}
+
+	/* Create the ucontext.  */
+	err |= __put_user(0, &frame->uc.uc_flags);
+	err |= __put_user(0, &frame->uc.uc_link);
+	err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));
+	err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
+			       set->sig[0]);
+
+	fp_to = (unsigned long)&frame->fpstate;
+
+	err |= __put_user(fp_to, &frame->uc.uc_mcontext.fpstate);
+	if (sizeof(*set) == 16) {
+		err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
+		err |= __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 (ksig->ka.sa.sa_flags & SA_RESTORER)
+		err |= __put_user((void *)ksig->ka.sa.sa_restorer,
+				  &frame->pretcode);
+	else
+		/* could use a vstub here */
+		return err;
+
+	if (err)
+		return err;
+
+	PT_REGS_SP(regs) = (unsigned long) frame;
+	PT_REGS_DI(regs) = sig;
+	/* In case the signal handler was declared without prototypes */
+	PT_REGS_AX(regs) = 0;
+
+	/*
+	 * This also works for non SA_SIGINFO handlers because they expect the
+	 * next argument after the signal number on the stack.
+	 */
+	PT_REGS_SI(regs) = (unsigned long) &frame->info;
+	PT_REGS_DX(regs) = (unsigned long) &frame->uc;
+	PT_REGS_IP(regs) = (unsigned long) ksig->ka.sa.sa_handler;
+ out:
+	return err;
+}
+#endif
+
+long sys_rt_sigreturn(void)
+{
+	unsigned long sp = PT_REGS_SP(&current->thread.regs);
+	struct rt_sigframe __user *frame =
+		(struct rt_sigframe __user *)(sp - sizeof(long));
+	struct ucontext __user *uc = &frame->uc;
+	sigset_t set;
+
+	if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
+		goto segfault;
+
+	set_current_blocked(&set);
+
+	if (copy_sc_from_user(&current->thread.regs, &uc->uc_mcontext))
+		goto segfault;
+
+	/* Avoid ERESTART handling */
+	PT_REGS_SYSCALL_NR(&current->thread.regs) = -1;
+	return PT_REGS_SYSCALL_RET(&current->thread.regs);
+
+ segfault:
+	force_sig(SIGSEGV);
+	return 0;
+}