1 files changed, 508 insertions, 0 deletions

diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c
new file mode 100644
index 00000000000..89a46626bfd
--- /dev/null
+++ b/arch/um/sys-i386/signal.c
@@ -0,0 +1,508 @@
+/*
+ * Copyright (C) 2004 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/ptrace.h>
+#include <asm/unistd.h>
+#include <asm/uaccess.h>
+#include <asm/ucontext.h>
+#include "frame_kern.h"
+#include "skas.h"
+
+void copy_sc(struct uml_pt_regs *regs, void *from)
+{
+        struct sigcontext *sc = from;
+
+        REGS_GS(regs->gp) = sc->gs;
+        REGS_FS(regs->gp) = sc->fs;
+        REGS_ES(regs->gp) = sc->es;
+        REGS_DS(regs->gp) = sc->ds;
+        REGS_EDI(regs->gp) = sc->di;
+        REGS_ESI(regs->gp) = sc->si;
+        REGS_EBP(regs->gp) = sc->bp;
+        REGS_SP(regs->gp) = sc->sp;
+        REGS_EBX(regs->gp) = sc->bx;
+        REGS_EDX(regs->gp) = sc->dx;
+        REGS_ECX(regs->gp) = sc->cx;
+        REGS_EAX(regs->gp) = sc->ax;
+        REGS_IP(regs->gp) = sc->ip;
+        REGS_CS(regs->gp) = sc->cs;
+        REGS_EFLAGS(regs->gp) = sc->flags;
+        REGS_SS(regs->gp) = sc->ss;
+}
+
+/*
+ * 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;
+
+static int copy_sc_from_user(struct pt_regs *regs,
+                             struct sigcontext __user *from)
+{
+        struct sigcontext sc;
+        int err, pid;
+
+        err = copy_from_user(&sc, from, sizeof(sc));
+        if (err)
+                return err;
+
+        pid = userspace_pid[current_thread_info()->cpu];
+        copy_sc(&regs->regs, &sc);
+        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, 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 {
+                struct user_i387_struct fp;
+
+                err = copy_from_user(&fp, sc.fpstate,
+                                     sizeof(struct user_i387_struct));
+                if (err)
+                        return 1;
+
+                err = restore_fp_registers(pid, (unsigned long *) &fp);
+                if (err < 0) {
+                        printk(KERN_ERR "copy_sc_from_user - "
+                               "restore_fp_registers failed, errno = %d\n",
+                               -err);
+                        return 1;
+                }
+        }
+
+        return 0;
+}
+
+static int copy_sc_to_user(struct sigcontext __user *to,
+                           struct _fpstate __user *to_fp, struct pt_regs *regs,
+                           unsigned long sp)
+{
+        struct sigcontext sc;
+        struct faultinfo * fi = &current->thread.arch.faultinfo;
+        int err, pid;
+
+        sc.gs = REGS_GS(regs->regs.gp);
+        sc.fs = REGS_FS(regs->regs.gp);
+        sc.es = REGS_ES(regs->regs.gp);
+        sc.ds = REGS_DS(regs->regs.gp);
+        sc.di = REGS_EDI(regs->regs.gp);
+        sc.si = REGS_ESI(regs->regs.gp);
+        sc.bp = REGS_EBP(regs->regs.gp);
+        sc.sp = sp;
+        sc.bx = REGS_EBX(regs->regs.gp);
+        sc.dx = REGS_EDX(regs->regs.gp);
+        sc.cx = REGS_ECX(regs->regs.gp);
+        sc.ax = REGS_EAX(regs->regs.gp);
+        sc.ip = REGS_IP(regs->regs.gp);
+        sc.cs = REGS_CS(regs->regs.gp);
+        sc.flags = REGS_EFLAGS(regs->regs.gp);
+        sc.sp_at_signal = regs->regs.gp[UESP];
+        sc.ss = regs->regs.gp[SS];
+        sc.cr2 = fi->cr2;
+        sc.err = fi->error_code;
+        sc.trapno = fi->trap_no;
+
+        to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
+        sc.fpstate = to_fp;
+
+        pid = userspace_pid[current_thread_info()->cpu];
+        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, &fpx);
+                if (err)
+                        return 1;
+
+                err |= __put_user(fpx.swd, &to_fp->status);
+                err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic);
+                if (err)
+                        return 1;
+
+                if (copy_to_user(&to_fp->_fxsr_env[0], &fpx,
+                                 sizeof(struct user_fxsr_struct)))
+                        return 1;
+        }
+        else {
+                struct user_i387_struct fp;
+
+                err = save_fp_registers(pid, (unsigned long *) &fp);
+                if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
+                        return 1;
+        }
+
+        return copy_to_user(to, &sc, sizeof(sc));
+}
+
+static int copy_ucontext_to_user(struct ucontext __user *uc,
+                                 struct _fpstate __user *fp, sigset_t *set,
+                                 unsigned long sp)
+{
+        int err = 0;
+
+        err |= put_user(current->sas_ss_sp, &uc->uc_stack.ss_sp);
+        err |= put_user(sas_ss_flags(sp), &uc->uc_stack.ss_flags);
+        err |= put_user(current->sas_ss_size, &uc->uc_stack.ss_size);
+        err |= copy_sc_to_user(&uc->uc_mcontext, fp, &current->thread.regs, sp);
+        err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set));
+        return err;
+}
+
+struct sigframe
+{
+        char __user *pretcode;
+        int sig;
+        struct sigcontext sc;
+        struct _fpstate 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 _fpstate fpstate;
+        char retcode[8];
+};
+
+int setup_signal_stack_sc(unsigned long stack_top, int sig,
+                          struct k_sigaction *ka, struct pt_regs *regs,
+                          sigset_t *mask)
+{
+        struct sigframe __user *frame;
+        void __user *restorer;
+        unsigned long save_sp = PT_REGS_SP(regs);
+        int err = 0;
+
+        /* 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(VERIFY_WRITE, frame, sizeof(*frame)))
+                return 1;
+
+        restorer = frame->retcode;
+        if (ka->sa.sa_flags & SA_RESTORER)
+                restorer = ka->sa.sa_restorer;
+
+        /* Update SP now because the page fault handler refuses to extend
+         * the stack if the faulting address is too far below the current
+         * SP, which frame now certainly is.  If there's an error, the original
+         * value is restored on the way out.
+         * When writing the sigcontext to the stack, we have to write the
+         * original value, so that's passed to copy_sc_to_user, which does
+         * the right thing with it.
+         */
+        PT_REGS_SP(regs) = (unsigned long) frame;
+
+        err |= __put_user(restorer, &frame->pretcode);
+        err |= __put_user(sig, &frame->sig);
+        err |= copy_sc_to_user(&frame->sc, NULL, regs, save_sp);
+        err |= __put_user(mask->sig[0], &frame->sc.oldmask);
+        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)
+                goto err;
+
+        PT_REGS_SP(regs) = (unsigned long) frame;
+        PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
+        PT_REGS_EAX(regs) = (unsigned long) sig;
+        PT_REGS_EDX(regs) = (unsigned long) 0;
+        PT_REGS_ECX(regs) = (unsigned long) 0;
+
+        if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
+                ptrace_notify(SIGTRAP);
+        return 0;
+
+err:
+        PT_REGS_SP(regs) = save_sp;
+        return err;
+}
+
+int setup_signal_stack_si(unsigned long stack_top, int sig,
+                          struct k_sigaction *ka, struct pt_regs *regs,
+                          siginfo_t *info, sigset_t *mask)
+{
+        struct rt_sigframe __user *frame;
+        void __user *restorer;
+        unsigned long save_sp = PT_REGS_SP(regs);
+        int err = 0;
+
+        stack_top &= -8UL;
+        frame = (struct rt_sigframe __user *) stack_top - 1;
+        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+                return 1;
+
+        restorer = frame->retcode;
+        if (ka->sa.sa_flags & SA_RESTORER)
+                restorer = ka->sa.sa_restorer;
+
+        /* See comment above about why this is here */
+        PT_REGS_SP(regs) = (unsigned long) frame;
+
+        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, info);
+        err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask,
+                                     save_sp);
+
+        /*
+         * 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)
+                goto err;
+
+        PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler;
+        PT_REGS_EAX(regs) = (unsigned long) sig;
+        PT_REGS_EDX(regs) = (unsigned long) &frame->info;
+        PT_REGS_ECX(regs) = (unsigned long) &frame->uc;
+
+        if ((current->ptrace & PT_DTRACE) && (current->ptrace & PT_PTRACED))
+                ptrace_notify(SIGTRAP);
+        return 0;
+
+err:
+        PT_REGS_SP(regs) = save_sp;
+        return err;
+}
+
+long sys_sigreturn(struct pt_regs regs)
+{
+        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;
+        unsigned long __user *oldmask = &sc->oldmask;
+        unsigned long __user *extramask = frame->extramask;
+        int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long);
+
+        if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) ||
+            copy_from_user(&set.sig[1], extramask, sig_size))
+                goto segfault;
+
+        sigdelsetmask(&set, ~_BLOCKABLE);
+
+        spin_lock_irq(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        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, current);
+        return 0;
+}
+
+long sys_rt_sigreturn(struct pt_regs regs)
+{
+        unsigned long sp = PT_REGS_SP(&current->thread.regs);
+        struct rt_sigframe __user *frame =
+                (struct rt_sigframe __user *) (sp - 4);
+        sigset_t set;
+        struct ucontext __user *uc = &frame->uc;
+        int sig_size = _NSIG_WORDS * sizeof(unsigned long);
+
+        if (copy_from_user(&set, &uc->uc_sigmask, sig_size))
+                goto segfault;
+
+        sigdelsetmask(&set, ~_BLOCKABLE);
+
+        spin_lock_irq(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        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, current);
+        return 0;
+}