Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 790 insertions, 0 deletions

diff --git a/linux-user/sparc/signal.c b/linux-user/sparc/signal.c
new file mode 100644
index 000000000..23e1e761d
--- /dev/null
+++ b/linux-user/sparc/signal.c
@@ -0,0 +1,790 @@
+/*
+ *  Emulation of Linux signals
+ *
+ *  Copyright (c) 2003 Fabrice Bellard
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "qemu/osdep.h"
+#include "qemu.h"
+#include "user-internals.h"
+#include "signal-common.h"
+#include "linux-user/trace.h"
+
+/* A Sparc register window */
+struct target_reg_window {
+    abi_ulong locals[8];
+    abi_ulong ins[8];
+};
+
+/* A Sparc stack frame. */
+struct target_stackf {
+    /*
+     * Since qemu does not reference fp or callers_pc directly,
+     * it's simpler to treat fp and callers_pc as elements of ins[],
+     * and then bundle locals[] and ins[] into reg_window.
+     */
+    struct target_reg_window win;
+    /*
+     * Similarly, bundle structptr and xxargs into xargs[].
+     * This portion of the struct is part of the function call abi,
+     * and belongs to the callee for spilling argument registers.
+     */
+    abi_ulong xargs[8];
+};
+
+struct target_siginfo_fpu {
+#ifdef TARGET_SPARC64
+    uint64_t si_double_regs[32];
+    uint64_t si_fsr;
+    uint64_t si_gsr;
+    uint64_t si_fprs;
+#else
+    /* It is more convenient for qemu to move doubles, not singles. */
+    uint64_t si_double_regs[16];
+    uint32_t si_fsr;
+    uint32_t si_fpqdepth;
+    struct {
+        uint32_t insn_addr;
+        uint32_t insn;
+    } si_fpqueue [16];
+#endif
+};
+
+#ifdef TARGET_ARCH_HAS_SETUP_FRAME
+struct target_signal_frame {
+    struct target_stackf ss;
+    struct target_pt_regs regs;
+    uint32_t si_mask;
+    abi_ulong fpu_save;
+    uint32_t insns[2] QEMU_ALIGNED(8);
+    abi_ulong extramask[TARGET_NSIG_WORDS - 1];
+    abi_ulong extra_size; /* Should be 0 */
+    abi_ulong rwin_save;
+};
+#endif
+
+struct target_rt_signal_frame {
+    struct target_stackf ss;
+    target_siginfo_t info;
+    struct target_pt_regs regs;
+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
+    abi_ulong fpu_save;
+    target_stack_t stack;
+    target_sigset_t mask;
+#else
+    target_sigset_t mask;
+    abi_ulong fpu_save;
+    uint32_t insns[2];
+    target_stack_t stack;
+    abi_ulong extra_size; /* Should be 0 */
+#endif
+    abi_ulong rwin_save;
+};
+
+static abi_ulong get_sigframe(struct target_sigaction *sa,
+                              CPUSPARCState *env,
+                              size_t framesize)
+{
+    abi_ulong sp = get_sp_from_cpustate(env);
+
+    /*
+     * 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 - framesize))) {
+        return -1;
+    }
+
+    /* This is the X/Open sanctioned signal stack switching.  */
+    sp = target_sigsp(sp, sa) - framesize;
+
+    /*
+     * Always align the stack frame.  This handles two cases.  First,
+     * sigaltstack need not be mindful of platform specific stack
+     * alignment.  Second, if we took this signal because the stack
+     * is not aligned properly, we'd like to take the signal cleanly
+     * and report that.
+     */
+    sp &= ~15UL;
+
+    return sp;
+}
+
+static void save_pt_regs(struct target_pt_regs *regs, CPUSPARCState *env)
+{
+    int i;
+
+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
+    __put_user(sparc64_tstate(env), &regs->tstate);
+    /* TODO: magic should contain PT_REG_MAGIC + %tt. */
+    __put_user(0, &regs->magic);
+#else
+    __put_user(cpu_get_psr(env), &regs->psr);
+#endif
+
+    __put_user(env->pc, &regs->pc);
+    __put_user(env->npc, &regs->npc);
+    __put_user(env->y, &regs->y);
+
+    for (i = 0; i < 8; i++) {
+        __put_user(env->gregs[i], &regs->u_regs[i]);
+    }
+    for (i = 0; i < 8; i++) {
+        __put_user(env->regwptr[WREG_O0 + i], &regs->u_regs[i + 8]);
+    }
+}
+
+static void restore_pt_regs(struct target_pt_regs *regs, CPUSPARCState *env)
+{
+    int i;
+
+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
+    /* User can only change condition codes and %asi in %tstate. */
+    uint64_t tstate;
+    __get_user(tstate, &regs->tstate);
+    cpu_put_ccr(env, tstate >> 32);
+    env->asi = extract64(tstate, 24, 8);
+#else
+    /*
+     * User can only change condition codes and FPU enabling in %psr.
+     * But don't bother with FPU enabling, since a real kernel would
+     * just re-enable the FPU upon the next fpu trap.
+     */
+    uint32_t psr;
+    __get_user(psr, &regs->psr);
+    env->psr = (psr & PSR_ICC) | (env->psr & ~PSR_ICC);
+#endif
+
+    /* Note that pc and npc are handled in the caller. */
+
+    __get_user(env->y, &regs->y);
+
+    for (i = 0; i < 8; i++) {
+        __get_user(env->gregs[i], &regs->u_regs[i]);
+    }
+    for (i = 0; i < 8; i++) {
+        __get_user(env->regwptr[WREG_O0 + i], &regs->u_regs[i + 8]);
+    }
+}
+
+static void save_reg_win(struct target_reg_window *win, CPUSPARCState *env)
+{
+    int i;
+
+    for (i = 0; i < 8; i++) {
+        __put_user(env->regwptr[i + WREG_L0], &win->locals[i]);
+    }
+    for (i = 0; i < 8; i++) {
+        __put_user(env->regwptr[i + WREG_I0], &win->ins[i]);
+    }
+}
+
+static void save_fpu(struct target_siginfo_fpu *fpu, CPUSPARCState *env)
+{
+    int i;
+
+#ifdef TARGET_SPARC64
+    for (i = 0; i < 32; ++i) {
+        __put_user(env->fpr[i].ll, &fpu->si_double_regs[i]);
+    }
+    __put_user(env->fsr, &fpu->si_fsr);
+    __put_user(env->gsr, &fpu->si_gsr);
+    __put_user(env->fprs, &fpu->si_fprs);
+#else
+    for (i = 0; i < 16; ++i) {
+        __put_user(env->fpr[i].ll, &fpu->si_double_regs[i]);
+    }
+    __put_user(env->fsr, &fpu->si_fsr);
+    __put_user(0, &fpu->si_fpqdepth);
+#endif
+}
+
+static void restore_fpu(struct target_siginfo_fpu *fpu, CPUSPARCState *env)
+{
+    int i;
+
+#ifdef TARGET_SPARC64
+    uint64_t fprs;
+    __get_user(fprs, &fpu->si_fprs);
+
+    /* In case the user mucks about with FPRS, restore as directed. */
+    if (fprs & FPRS_DL) {
+        for (i = 0; i < 16; ++i) {
+            __get_user(env->fpr[i].ll, &fpu->si_double_regs[i]);
+        }
+    }
+    if (fprs & FPRS_DU) {
+        for (i = 16; i < 32; ++i) {
+            __get_user(env->fpr[i].ll, &fpu->si_double_regs[i]);
+        }
+    }
+    __get_user(env->fsr, &fpu->si_fsr);
+    __get_user(env->gsr, &fpu->si_gsr);
+    env->fprs |= fprs;
+#else
+    for (i = 0; i < 16; ++i) {
+        __get_user(env->fpr[i].ll, &fpu->si_double_regs[i]);
+    }
+    __get_user(env->fsr, &fpu->si_fsr);
+#endif
+}
+
+#ifdef TARGET_ARCH_HAS_SETUP_FRAME
+static void install_sigtramp(uint32_t *tramp, int syscall)
+{
+    __put_user(0x82102000u + syscall, &tramp[0]); /* mov syscall, %g1 */
+    __put_user(0x91d02010u, &tramp[1]);           /* t 0x10 */
+}
+
+void setup_frame(int sig, struct target_sigaction *ka,
+                 target_sigset_t *set, CPUSPARCState *env)
+{
+    abi_ulong sf_addr;
+    struct target_signal_frame *sf;
+    size_t sf_size = sizeof(*sf) + sizeof(struct target_siginfo_fpu);
+    int i;
+
+    sf_addr = get_sigframe(ka, env, sf_size);
+    trace_user_setup_frame(env, sf_addr);
+
+    sf = lock_user(VERIFY_WRITE, sf_addr, sf_size, 0);
+    if (!sf) {
+        force_sigsegv(sig);
+        return;
+    }
+
+    /* 2. Save the current process state */
+    save_pt_regs(&sf->regs, env);
+    __put_user(0, &sf->extra_size);
+
+    save_fpu((struct target_siginfo_fpu *)(sf + 1), env);
+    __put_user(sf_addr + sizeof(*sf), &sf->fpu_save);
+
+    __put_user(0, &sf->rwin_save);  /* TODO: save_rwin_state */
+
+    __put_user(set->sig[0], &sf->si_mask);
+    for (i = 0; i < TARGET_NSIG_WORDS - 1; i++) {
+        __put_user(set->sig[i + 1], &sf->extramask[i]);
+    }
+
+    save_reg_win(&sf->ss.win, env);
+
+    /* 3. signal handler back-trampoline and parameters */
+    env->regwptr[WREG_SP] = sf_addr;
+    env->regwptr[WREG_O0] = sig;
+    env->regwptr[WREG_O1] = sf_addr +
+            offsetof(struct target_signal_frame, regs);
+    env->regwptr[WREG_O2] = sf_addr +
+            offsetof(struct target_signal_frame, regs);
+
+    /* 4. signal handler */
+    env->pc = ka->_sa_handler;
+    env->npc = env->pc + 4;
+
+    /* 5. return to kernel instructions */
+    if (ka->ka_restorer) {
+        env->regwptr[WREG_O7] = ka->ka_restorer;
+    } else {
+        /* Not used, but retain for ABI compatibility. */
+        install_sigtramp(sf->insns, TARGET_NR_sigreturn);
+        env->regwptr[WREG_O7] = default_sigreturn;
+    }
+    unlock_user(sf, sf_addr, sf_size);
+}
+#endif /* TARGET_ARCH_HAS_SETUP_FRAME */
+
+void setup_rt_frame(int sig, struct target_sigaction *ka,
+                    target_siginfo_t *info,
+                    target_sigset_t *set, CPUSPARCState *env)
+{
+    abi_ulong sf_addr;
+    struct target_rt_signal_frame *sf;
+    size_t sf_size = sizeof(*sf) + sizeof(struct target_siginfo_fpu);
+
+    sf_addr = get_sigframe(ka, env, sf_size);
+    trace_user_setup_rt_frame(env, sf_addr);
+
+    sf = lock_user(VERIFY_WRITE, sf_addr, sf_size, 0);
+    if (!sf) {
+        force_sigsegv(sig);
+        return;
+    }
+
+    /* 2. Save the current process state */
+    save_reg_win(&sf->ss.win, env);
+    save_pt_regs(&sf->regs, env);
+
+    save_fpu((struct target_siginfo_fpu *)(sf + 1), env);
+    __put_user(sf_addr + sizeof(*sf), &sf->fpu_save);
+
+    __put_user(0, &sf->rwin_save);  /* TODO: save_rwin_state */
+
+    tswap_siginfo(&sf->info, info);
+    tswap_sigset(&sf->mask, set);
+    target_save_altstack(&sf->stack, env);
+
+#ifdef TARGET_ABI32
+    __put_user(0, &sf->extra_size);
+#endif
+
+    /* 3. signal handler back-trampoline and parameters */
+    env->regwptr[WREG_SP] = sf_addr - TARGET_STACK_BIAS;
+    env->regwptr[WREG_O0] = sig;
+    env->regwptr[WREG_O1] =
+        sf_addr + offsetof(struct target_rt_signal_frame, info);
+#ifdef TARGET_ABI32
+    env->regwptr[WREG_O2] =
+        sf_addr + offsetof(struct target_rt_signal_frame, regs);
+#else
+    env->regwptr[WREG_O2] = env->regwptr[WREG_O1];
+#endif
+
+    /* 4. signal handler */
+    env->pc = ka->_sa_handler;
+    env->npc = env->pc + 4;
+
+    /* 5. return to kernel instructions */
+#ifdef TARGET_ABI32
+    if (ka->ka_restorer) {
+        env->regwptr[WREG_O7] = ka->ka_restorer;
+    } else {
+        /* Not used, but retain for ABI compatibility. */
+        install_sigtramp(sf->insns, TARGET_NR_rt_sigreturn);
+        env->regwptr[WREG_O7] = default_rt_sigreturn;
+    }
+#else
+    env->regwptr[WREG_O7] = ka->ka_restorer;
+#endif
+
+    unlock_user(sf, sf_addr, sf_size);
+}
+
+long do_sigreturn(CPUSPARCState *env)
+{
+#ifdef TARGET_ARCH_HAS_SETUP_FRAME
+    abi_ulong sf_addr;
+    struct target_signal_frame *sf = NULL;
+    abi_ulong pc, npc, ptr;
+    target_sigset_t set;
+    sigset_t host_set;
+    int i;
+
+    sf_addr = env->regwptr[WREG_SP];
+    trace_user_do_sigreturn(env, sf_addr);
+
+    /* 1. Make sure we are not getting garbage from the user */
+    if ((sf_addr & 15) || !lock_user_struct(VERIFY_READ, sf, sf_addr, 1)) {
+        goto segv_and_exit;
+    }
+
+    /* Make sure stack pointer is aligned.  */
+    __get_user(ptr, &sf->regs.u_regs[14]);
+    if (ptr & 7) {
+        goto segv_and_exit;
+    }
+
+    /* Make sure instruction pointers are aligned.  */
+    __get_user(pc, &sf->regs.pc);
+    __get_user(npc, &sf->regs.npc);
+    if ((pc | npc) & 3) {
+        goto segv_and_exit;
+    }
+
+    /* 2. Restore the state */
+    restore_pt_regs(&sf->regs, env);
+    env->pc = pc;
+    env->npc = npc;
+
+    __get_user(ptr, &sf->fpu_save);
+    if (ptr) {
+        struct target_siginfo_fpu *fpu;
+        if ((ptr & 3) || !lock_user_struct(VERIFY_READ, fpu, ptr, 1)) {
+            goto segv_and_exit;
+        }
+        restore_fpu(fpu, env);
+        unlock_user_struct(fpu, ptr, 0);
+    }
+
+    __get_user(ptr, &sf->rwin_save);
+    if (ptr) {
+        goto segv_and_exit;  /* TODO: restore_rwin */
+    }
+
+    __get_user(set.sig[0], &sf->si_mask);
+    for (i = 1; i < TARGET_NSIG_WORDS; i++) {
+        __get_user(set.sig[i], &sf->extramask[i - 1]);
+    }
+
+    target_to_host_sigset_internal(&host_set, &set);
+    set_sigmask(&host_set);
+
+    unlock_user_struct(sf, sf_addr, 0);
+    return -TARGET_QEMU_ESIGRETURN;
+
+ segv_and_exit:
+    unlock_user_struct(sf, sf_addr, 0);
+    force_sig(TARGET_SIGSEGV);
+    return -TARGET_QEMU_ESIGRETURN;
+#else
+    return -TARGET_ENOSYS;
+#endif
+}
+
+long do_rt_sigreturn(CPUSPARCState *env)
+{
+    abi_ulong sf_addr, tpc, tnpc, ptr;
+    struct target_rt_signal_frame *sf = NULL;
+    sigset_t set;
+
+    sf_addr = get_sp_from_cpustate(env);
+    trace_user_do_rt_sigreturn(env, sf_addr);
+
+    /* 1. Make sure we are not getting garbage from the user */
+    if ((sf_addr & 15) || !lock_user_struct(VERIFY_READ, sf, sf_addr, 1)) {
+        goto segv_and_exit;
+    }
+
+    /* Validate SP alignment.  */
+    __get_user(ptr, &sf->regs.u_regs[8 + WREG_SP]);
+    if ((ptr + TARGET_STACK_BIAS) & 7) {
+        goto segv_and_exit;
+    }
+
+    /* Validate PC and NPC alignment.  */
+    __get_user(tpc, &sf->regs.pc);
+    __get_user(tnpc, &sf->regs.npc);
+    if ((tpc | tnpc) & 3) {
+        goto segv_and_exit;
+    }
+
+    /* 2. Restore the state */
+    restore_pt_regs(&sf->regs, env);
+
+    __get_user(ptr, &sf->fpu_save);
+    if (ptr) {
+        struct target_siginfo_fpu *fpu;
+        if ((ptr & 7) || !lock_user_struct(VERIFY_READ, fpu, ptr, 1)) {
+            goto segv_and_exit;
+        }
+        restore_fpu(fpu, env);
+        unlock_user_struct(fpu, ptr, 0);
+    }
+
+    __get_user(ptr, &sf->rwin_save);
+    if (ptr) {
+        goto segv_and_exit;  /* TODO: restore_rwin_state */
+    }
+
+    target_restore_altstack(&sf->stack, env);
+    target_to_host_sigset(&set, &sf->mask);
+    set_sigmask(&set);
+
+    env->pc = tpc;
+    env->npc = tnpc;
+
+    unlock_user_struct(sf, sf_addr, 0);
+    return -TARGET_QEMU_ESIGRETURN;
+
+ segv_and_exit:
+    unlock_user_struct(sf, sf_addr, 0);
+    force_sig(TARGET_SIGSEGV);
+    return -TARGET_QEMU_ESIGRETURN;
+}
+
+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
+#define SPARC_MC_TSTATE 0
+#define SPARC_MC_PC 1
+#define SPARC_MC_NPC 2
+#define SPARC_MC_Y 3
+#define SPARC_MC_G1 4
+#define SPARC_MC_G2 5
+#define SPARC_MC_G3 6
+#define SPARC_MC_G4 7
+#define SPARC_MC_G5 8
+#define SPARC_MC_G6 9
+#define SPARC_MC_G7 10
+#define SPARC_MC_O0 11
+#define SPARC_MC_O1 12
+#define SPARC_MC_O2 13
+#define SPARC_MC_O3 14
+#define SPARC_MC_O4 15
+#define SPARC_MC_O5 16
+#define SPARC_MC_O6 17
+#define SPARC_MC_O7 18
+#define SPARC_MC_NGREG 19
+
+typedef abi_ulong target_mc_greg_t;
+typedef target_mc_greg_t target_mc_gregset_t[SPARC_MC_NGREG];
+
+struct target_mc_fq {
+    abi_ulong mcfq_addr;
+    uint32_t mcfq_insn;
+};
+
+/*
+ * Note the manual 16-alignment; the kernel gets this because it
+ * includes a "long double qregs[16]" in the mcpu_fregs union,
+ * which we can't do.
+ */
+struct target_mc_fpu {
+    union {
+        uint32_t sregs[32];
+        uint64_t dregs[32];
+        //uint128_t qregs[16];
+    } mcfpu_fregs;
+    abi_ulong mcfpu_fsr;
+    abi_ulong mcfpu_fprs;
+    abi_ulong mcfpu_gsr;
+    abi_ulong mcfpu_fq;
+    unsigned char mcfpu_qcnt;
+    unsigned char mcfpu_qentsz;
+    unsigned char mcfpu_enab;
+} __attribute__((aligned(16)));
+typedef struct target_mc_fpu target_mc_fpu_t;
+
+typedef struct {
+    target_mc_gregset_t mc_gregs;
+    target_mc_greg_t mc_fp;
+    target_mc_greg_t mc_i7;
+    target_mc_fpu_t mc_fpregs;
+} target_mcontext_t;
+
+struct target_ucontext {
+    abi_ulong tuc_link;
+    abi_ulong tuc_flags;
+    target_sigset_t tuc_sigmask;
+    target_mcontext_t tuc_mcontext;
+};
+
+/* {set, get}context() needed for 64-bit SparcLinux userland. */
+void sparc64_set_context(CPUSPARCState *env)
+{
+    abi_ulong ucp_addr;
+    struct target_ucontext *ucp;
+    target_mc_gregset_t *grp;
+    target_mc_fpu_t *fpup;
+    abi_ulong pc, npc, tstate;
+    unsigned int i;
+    unsigned char fenab;
+
+    ucp_addr = env->regwptr[WREG_O0];
+    if (!lock_user_struct(VERIFY_READ, ucp, ucp_addr, 1)) {
+        goto do_sigsegv;
+    }
+    grp  = &ucp->tuc_mcontext.mc_gregs;
+    __get_user(pc, &((*grp)[SPARC_MC_PC]));
+    __get_user(npc, &((*grp)[SPARC_MC_NPC]));
+    if ((pc | npc) & 3) {
+        goto do_sigsegv;
+    }
+    if (env->regwptr[WREG_O1]) {
+        target_sigset_t target_set;
+        sigset_t set;
+
+        if (TARGET_NSIG_WORDS == 1) {
+            __get_user(target_set.sig[0], &ucp->tuc_sigmask.sig[0]);
+        } else {
+            abi_ulong *src, *dst;
+            src = ucp->tuc_sigmask.sig;
+            dst = target_set.sig;
+            for (i = 0; i < TARGET_NSIG_WORDS; i++, dst++, src++) {
+                __get_user(*dst, src);
+            }
+        }
+        target_to_host_sigset_internal(&set, &target_set);
+        set_sigmask(&set);
+    }
+    env->pc = pc;
+    env->npc = npc;
+    __get_user(env->y, &((*grp)[SPARC_MC_Y]));
+    __get_user(tstate, &((*grp)[SPARC_MC_TSTATE]));
+    /* Honour TSTATE_ASI, TSTATE_ICC and TSTATE_XCC only */
+    env->asi = (tstate >> 24) & 0xff;
+    cpu_put_ccr(env, (tstate >> 32) & 0xff);
+    __get_user(env->gregs[1], (&(*grp)[SPARC_MC_G1]));
+    __get_user(env->gregs[2], (&(*grp)[SPARC_MC_G2]));
+    __get_user(env->gregs[3], (&(*grp)[SPARC_MC_G3]));
+    __get_user(env->gregs[4], (&(*grp)[SPARC_MC_G4]));
+    __get_user(env->gregs[5], (&(*grp)[SPARC_MC_G5]));
+    __get_user(env->gregs[6], (&(*grp)[SPARC_MC_G6]));
+    /* Skip g7 as that's the thread register in userspace */
+
+    /*
+     * Note that unlike the kernel, we didn't need to mess with the
+     * guest register window state to save it into a pt_regs to run
+     * the kernel. So for us the guest's O regs are still in WREG_O*
+     * (unlike the kernel which has put them in UREG_I* in a pt_regs)
+     * and the fp and i7 are still in WREG_I6 and WREG_I7 and don't
+     * need to be written back to userspace memory.
+     */
+    __get_user(env->regwptr[WREG_O0], (&(*grp)[SPARC_MC_O0]));
+    __get_user(env->regwptr[WREG_O1], (&(*grp)[SPARC_MC_O1]));
+    __get_user(env->regwptr[WREG_O2], (&(*grp)[SPARC_MC_O2]));
+    __get_user(env->regwptr[WREG_O3], (&(*grp)[SPARC_MC_O3]));
+    __get_user(env->regwptr[WREG_O4], (&(*grp)[SPARC_MC_O4]));
+    __get_user(env->regwptr[WREG_O5], (&(*grp)[SPARC_MC_O5]));
+    __get_user(env->regwptr[WREG_O6], (&(*grp)[SPARC_MC_O6]));
+    __get_user(env->regwptr[WREG_O7], (&(*grp)[SPARC_MC_O7]));
+
+    __get_user(env->regwptr[WREG_FP], &(ucp->tuc_mcontext.mc_fp));
+    __get_user(env->regwptr[WREG_I7], &(ucp->tuc_mcontext.mc_i7));
+
+    fpup = &ucp->tuc_mcontext.mc_fpregs;
+
+    __get_user(fenab, &(fpup->mcfpu_enab));
+    if (fenab) {
+        abi_ulong fprs;
+
+        /*
+         * We use the FPRS from the guest only in deciding whether
+         * to restore the upper, lower, or both banks of the FPU regs.
+         * The kernel here writes the FPU register data into the
+         * process's current_thread_info state and unconditionally
+         * clears FPRS and TSTATE_PEF: this disables the FPU so that the
+         * next FPU-disabled trap will copy the data out of
+         * current_thread_info and into the real FPU registers.
+         * QEMU doesn't need to handle lazy-FPU-state-restoring like that,
+         * so we always load the data directly into the FPU registers
+         * and leave FPRS and TSTATE_PEF alone (so the FPU stays enabled).
+         * Note that because we (and the kernel) always write zeroes for
+         * the fenab and fprs in sparc64_get_context() none of this code
+         * will execute unless the guest manually constructed or changed
+         * the context structure.
+         */
+        __get_user(fprs, &(fpup->mcfpu_fprs));
+        if (fprs & FPRS_DL) {
+            for (i = 0; i < 16; i++) {
+                __get_user(env->fpr[i].ll, &(fpup->mcfpu_fregs.dregs[i]));
+            }
+        }
+        if (fprs & FPRS_DU) {
+            for (i = 16; i < 32; i++) {
+                __get_user(env->fpr[i].ll, &(fpup->mcfpu_fregs.dregs[i]));
+            }
+        }
+        __get_user(env->fsr, &(fpup->mcfpu_fsr));
+        __get_user(env->gsr, &(fpup->mcfpu_gsr));
+    }
+    unlock_user_struct(ucp, ucp_addr, 0);
+    return;
+do_sigsegv:
+    unlock_user_struct(ucp, ucp_addr, 0);
+    force_sig(TARGET_SIGSEGV);
+}
+
+void sparc64_get_context(CPUSPARCState *env)
+{
+    abi_ulong ucp_addr;
+    struct target_ucontext *ucp;
+    target_mc_gregset_t *grp;
+    target_mcontext_t *mcp;
+    int err;
+    unsigned int i;
+    target_sigset_t target_set;
+    sigset_t set;
+
+    ucp_addr = env->regwptr[WREG_O0];
+    if (!lock_user_struct(VERIFY_WRITE, ucp, ucp_addr, 0)) {
+        goto do_sigsegv;
+    }
+
+    memset(ucp, 0, sizeof(*ucp));
+
+    mcp = &ucp->tuc_mcontext;
+    grp = &mcp->mc_gregs;
+
+    /* Skip over the trap instruction, first. */
+    env->pc = env->npc;
+    env->npc += 4;
+
+    /* If we're only reading the signal mask then do_sigprocmask()
+     * is guaranteed not to fail, which is important because we don't
+     * have any way to signal a failure or restart this operation since
+     * this is not a normal syscall.
+     */
+    err = do_sigprocmask(0, NULL, &set);
+    assert(err == 0);
+    host_to_target_sigset_internal(&target_set, &set);
+    if (TARGET_NSIG_WORDS == 1) {
+        __put_user(target_set.sig[0],
+                   (abi_ulong *)&ucp->tuc_sigmask);
+    } else {
+        abi_ulong *src, *dst;
+        src = target_set.sig;
+        dst = ucp->tuc_sigmask.sig;
+        for (i = 0; i < TARGET_NSIG_WORDS; i++, dst++, src++) {
+            __put_user(*src, dst);
+        }
+    }
+
+    __put_user(sparc64_tstate(env), &((*grp)[SPARC_MC_TSTATE]));
+    __put_user(env->pc, &((*grp)[SPARC_MC_PC]));
+    __put_user(env->npc, &((*grp)[SPARC_MC_NPC]));
+    __put_user(env->y, &((*grp)[SPARC_MC_Y]));
+    __put_user(env->gregs[1], &((*grp)[SPARC_MC_G1]));
+    __put_user(env->gregs[2], &((*grp)[SPARC_MC_G2]));
+    __put_user(env->gregs[3], &((*grp)[SPARC_MC_G3]));
+    __put_user(env->gregs[4], &((*grp)[SPARC_MC_G4]));
+    __put_user(env->gregs[5], &((*grp)[SPARC_MC_G5]));
+    __put_user(env->gregs[6], &((*grp)[SPARC_MC_G6]));
+    __put_user(env->gregs[7], &((*grp)[SPARC_MC_G7]));
+
+    /*
+     * Note that unlike the kernel, we didn't need to mess with the
+     * guest register window state to save it into a pt_regs to run
+     * the kernel. So for us the guest's O regs are still in WREG_O*
+     * (unlike the kernel which has put them in UREG_I* in a pt_regs)
+     * and the fp and i7 are still in WREG_I6 and WREG_I7 and don't
+     * need to be fished out of userspace memory.
+     */
+    __put_user(env->regwptr[WREG_O0], &((*grp)[SPARC_MC_O0]));
+    __put_user(env->regwptr[WREG_O1], &((*grp)[SPARC_MC_O1]));
+    __put_user(env->regwptr[WREG_O2], &((*grp)[SPARC_MC_O2]));
+    __put_user(env->regwptr[WREG_O3], &((*grp)[SPARC_MC_O3]));
+    __put_user(env->regwptr[WREG_O4], &((*grp)[SPARC_MC_O4]));
+    __put_user(env->regwptr[WREG_O5], &((*grp)[SPARC_MC_O5]));
+    __put_user(env->regwptr[WREG_O6], &((*grp)[SPARC_MC_O6]));
+    __put_user(env->regwptr[WREG_O7], &((*grp)[SPARC_MC_O7]));
+
+    __put_user(env->regwptr[WREG_FP], &(mcp->mc_fp));
+    __put_user(env->regwptr[WREG_I7], &(mcp->mc_i7));
+
+    /*
+     * We don't write out the FPU state. This matches the kernel's
+     * implementation (which has the code for doing this but
+     * hidden behind an "if (fenab)" where fenab is always 0).
+     */
+
+    unlock_user_struct(ucp, ucp_addr, 1);
+    return;
+do_sigsegv:
+    unlock_user_struct(ucp, ucp_addr, 1);
+    force_sig(TARGET_SIGSEGV);
+}
+#else
+void setup_sigtramp(abi_ulong sigtramp_page)
+{
+    uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 2 * 8, 0);
+    assert(tramp != NULL);
+
+    default_sigreturn = sigtramp_page;
+    install_sigtramp(tramp, TARGET_NR_sigreturn);
+
+    default_rt_sigreturn = sigtramp_page + 8;
+    install_sigtramp(tramp + 2, TARGET_NR_rt_sigreturn);
+
+    unlock_user(tramp, sigtramp_page, 2 * 8);
+}
+#endif