/*
 * 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 <linux/syscalls.h>
#include <asm/unistd.h>
#include <linux/uaccess.h>
#include <asm/ucontext.h>
#include <frame_kern.h>
#include <registers.h>
#include <skas.h>

#include <linux/regset.h>
#include <asm/sigframe.h>

#ifdef CONFIG_X86_32
struct _xstate_64 {
        struct _fpstate_64              fpstate;
        struct _header                  xstate_hdr;
        struct _ymmh_state              ymmh;
        /* New processor state extensions go here: */
};
#else
#define _xstate_64 _xstate
#endif

static int copy_sc_from_user(struct pt_regs *regs,
                             struct sigcontext __user *from)
{
        struct _xstate_64 __user *from_fp64;
        struct sigcontext sc;
        int err;

        /* 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

#ifdef CONFIG_X86_32
        from_fp64 = ((void __user *)sc.fpstate) +
                    offsetof(struct _fpstate_32, _fxsr_env);
#else
        from_fp64 = (void __user *)sc.fpstate;
#endif

        err = copy_from_user(regs->regs.fp, from_fp64, host_fp_size);
        if (err)
                return 1;

#ifdef CONFIG_X86_32
        /* Data is duplicated and this copy is the important one */
        err = copy_regset_from_user(current,
                                    task_user_regset_view(current),
                                    REGSET_FP_LEGACY, 0,
                                    sizeof(struct user_i387_struct),
                                    (void __user *)sc.fpstate);
        if (err < 0)
                return err;
#endif

        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 _xstate_64 __user *to_fp64;
        struct sigcontext sc;
        struct faultinfo * fi = &current->thread.arch.faultinfo;
        int err;
        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;

#ifdef CONFIG_X86_32
        err = copy_regset_to_user(current,
                                  task_user_regset_view(current),
                                  REGSET_FP_LEGACY, 0,
                                  sizeof(struct _fpstate_32), to_fp);
        if (err < 0)
                return err;

        __put_user(X86_FXSR_MAGIC, &to_fp->fpstate.magic);

        BUILD_BUG_ON(offsetof(struct _xstate, xstate_hdr) !=
                     offsetof(struct _xstate_64, xstate_hdr) +
                        offsetof(struct _fpstate_32, _fxsr_env));
        to_fp64 = (void __user *)to_fp +
                  offsetof(struct _fpstate_32, _fxsr_env);
#else
        to_fp64 = to_fp;
#endif /* CONFIG_X86_32 */

        if (copy_to_user(to_fp64, regs->regs.fp, host_fp_size))
                return 1;

        /*
         * Put magic/size values for userspace. We do not bother to verify them
         * later on, however, userspace needs them should it try to read the
         * XSTATE data. And ptrace does not fill in these parts.
         *
         * Skip this if we do not have an XSTATE frame.
         */
        if (host_fp_size <= sizeof(to_fp64->fpstate))
                return 0;

        BUILD_BUG_ON(sizeof(int) != FP_XSTATE_MAGIC2_SIZE);
#ifdef CONFIG_X86_32
        __put_user(offsetof(struct _fpstate_32, _fxsr_env) +
                   host_fp_size + FP_XSTATE_MAGIC2_SIZE,
                   &to_fp64->fpstate.sw_reserved.extended_size);
#else
        __put_user(host_fp_size + FP_XSTATE_MAGIC2_SIZE,
                   &to_fp64->fpstate.sw_reserved.extended_size);
#endif
        __put_user(host_fp_size, &to_fp64->fpstate.sw_reserved.xstate_size);

        __put_user(FP_XSTATE_MAGIC1, &to_fp64->fpstate.sw_reserved.magic1);
        __put_user(FP_XSTATE_MAGIC2,
                   (int __user *)((void __user *)to_fp64 + host_fp_size));

        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;
}

int setup_signal_stack_sc(unsigned long stack_top, struct ksignal *ksig,
                          struct pt_regs *regs, sigset_t *mask)
{
        size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
                           host_fp_size + FP_XSTATE_MAGIC2_SIZE;
        struct sigframe __user *frame;
        void __user *restorer;
        int err = 0, sig = ksig->sig;
        unsigned long fp_to;

        /* 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;

        /* Add required space for math frame */
        frame = (struct sigframe __user *)((unsigned long)frame - math_size);

        restorer = frame->retcode;
        if (ksig->ka.sa.sa_flags & SA_RESTORER)
                restorer = ksig->ka.sa.sa_restorer;

        err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
        err |= __put_user(sig, &frame->sig);

        fp_to = (unsigned long)frame + sizeof(*frame);

        err |= copy_sc_to_user(&frame->sc,
                               (struct _xstate __user *)fp_to,
                               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)
{
        size_t math_size = offsetof(struct _fpstate_32, _fxsr_env) +
                           host_fp_size + FP_XSTATE_MAGIC2_SIZE;
        struct rt_sigframe __user *frame;
        void __user *restorer;
        int err = 0, sig = ksig->sig;
        unsigned long fp_to;

        stack_top &= -8UL;
        frame = (struct rt_sigframe __user *) stack_top - 1;
        if (!access_ok(frame, sizeof(*frame)))
                return 1;

        /* Add required space for math frame */
        frame = (struct rt_sigframe __user *)((unsigned long)frame - math_size);

        restorer = frame->retcode;
        if (ksig->ka.sa.sa_flags & SA_RESTORER)
                restorer = ksig->ka.sa.sa_restorer;

        err |= __put_user(restorer, (void __user * __user *)&frame->pretcode);
        err |= __put_user(sig, &frame->sig);
        err |= __put_user(&frame->info, (void __user * __user *)&frame->pinfo);
        err |= __put_user(&frame->uc, (void __user * __user *)&frame->puc);
        err |= copy_siginfo_to_user(&frame->info, &ksig->info);

        fp_to = (unsigned long)frame + sizeof(*frame);

        err |= copy_ucontext_to_user(&frame->uc, (struct _xstate __user *)fp_to,
                                     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;
}

SYSCALL_DEFINE0(sigreturn)
{
        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

int setup_signal_stack_si(unsigned long stack_top, struct ksignal *ksig,
                          struct pt_regs *regs, sigset_t *set)
{
        unsigned long math_size = host_fp_size + FP_XSTATE_MAGIC2_SIZE;
        struct rt_sigframe __user *frame;
        int err = 0, sig = ksig->sig;
        unsigned long fp_to;

        frame = (void __user *)stack_top - sizeof(struct rt_sigframe);

        /* Add required space for math frame */
        frame = (void __user *)((unsigned long)frame - math_size);

        /* ABI requires 16 byte boundary alignment */
        frame = (void __user *)round_down((unsigned long)frame, 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) + math_size))
                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(NULL, &frame->uc.uc_link);
        err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs));

        fp_to = (unsigned long)frame + sizeof(*frame);

        err |= copy_sc_to_user(&frame->uc.uc_mcontext,
                               (struct _xstate __user *)fp_to,
                               regs, set->sig[0]);

        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 __user *)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

SYSCALL_DEFINE0(rt_sigreturn)
{
        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;
}