cpu_loop.c

/*
 *  qemu user cpu loop
 *
 *  Copyright (c) 2003-2008 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-common.h"
#include "qemu.h"
#include "cpu_loop-common.h"

static void gen_sigill_reg(CPUTLGState *env)
{
    target_siginfo_t info;

    info.si_signo = TARGET_SIGILL;
    info.si_errno = 0;
    info.si_code = TARGET_ILL_PRVREG;
    info._sifields._sigfault._addr = env->pc;
    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
}

static void do_signal(CPUTLGState *env, int signo, int sigcode)
{
    target_siginfo_t info;

    info.si_signo = signo;
    info.si_errno = 0;
    info._sifields._sigfault._addr = env->pc;

    if (signo == TARGET_SIGSEGV) {
        /* The passed in sigcode is a dummy; check for a page mapping
           and pass either MAPERR or ACCERR.  */
        target_ulong addr = env->excaddr;
        info._sifields._sigfault._addr = addr;
        if (page_check_range(addr, 1, PAGE_VALID) < 0) {
            sigcode = TARGET_SEGV_MAPERR;
        } else {
            sigcode = TARGET_SEGV_ACCERR;
        }
    }
    info.si_code = sigcode;

    queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
}

static void gen_sigsegv_maperr(CPUTLGState *env, target_ulong addr)
{
    env->excaddr = addr;
    do_signal(env, TARGET_SIGSEGV, 0);
}

static void set_regval(CPUTLGState *env, uint8_t reg, uint64_t val)
{
    if (unlikely(reg >= TILEGX_R_COUNT)) {
        switch (reg) {
        case TILEGX_R_SN:
        case TILEGX_R_ZERO:
            return;
        case TILEGX_R_IDN0:
        case TILEGX_R_IDN1:
        case TILEGX_R_UDN0:
        case TILEGX_R_UDN1:
        case TILEGX_R_UDN2:
        case TILEGX_R_UDN3:
            gen_sigill_reg(env);
            return;
        default:
            g_assert_not_reached();
        }
    }
    env->regs[reg] = val;
}

/*
 * Compare the 8-byte contents of the CmpValue SPR with the 8-byte value in
 * memory at the address held in the first source register. If the values are
 * not equal, then no memory operation is performed. If the values are equal,
 * the 8-byte quantity from the second source register is written into memory
 * at the address held in the first source register. In either case, the result
 * of the instruction is the value read from memory. The compare and write to
 * memory are atomic and thus can be used for synchronization purposes. This
 * instruction only operates for addresses aligned to a 8-byte boundary.
 * Unaligned memory access causes an Unaligned Data Reference interrupt.
 *
 * Functional Description (64-bit)
 *       uint64_t memVal = memoryReadDoubleWord (rf[SrcA]);
 *       rf[Dest] = memVal;
 *       if (memVal == SPR[CmpValueSPR])
 *           memoryWriteDoubleWord (rf[SrcA], rf[SrcB]);
 *
 * Functional Description (32-bit)
 *       uint64_t memVal = signExtend32 (memoryReadWord (rf[SrcA]));
 *       rf[Dest] = memVal;
 *       if (memVal == signExtend32 (SPR[CmpValueSPR]))
 *           memoryWriteWord (rf[SrcA], rf[SrcB]);
 *
 *
 * This function also processes exch and exch4 which need not process SPR.
 */
static void do_exch(CPUTLGState *env, bool quad, bool cmp)
{
    target_ulong addr;
    target_long val, sprval;

    start_exclusive();

    addr = env->atomic_srca;
    if (quad ? get_user_s64(val, addr) : get_user_s32(val, addr)) {
        goto sigsegv_maperr;
    }

    if (cmp) {
        if (quad) {
            sprval = env->spregs[TILEGX_SPR_CMPEXCH];
        } else {
            sprval = sextract64(env->spregs[TILEGX_SPR_CMPEXCH], 0, 32);
        }
    }

    if (!cmp || val == sprval) {
        target_long valb = env->atomic_srcb;
        if (quad ? put_user_u64(valb, addr) : put_user_u32(valb, addr)) {
            goto sigsegv_maperr;
        }
    }

    set_regval(env, env->atomic_dstr, val);
    end_exclusive();
    return;

 sigsegv_maperr:
    end_exclusive();
    gen_sigsegv_maperr(env, addr);
}

static void do_fetch(CPUTLGState *env, int trapnr, bool quad)
{
    int8_t write = 1;
    target_ulong addr;
    target_long val, valb;

    start_exclusive();

    addr = env->atomic_srca;
    valb = env->atomic_srcb;
    if (quad ? get_user_s64(val, addr) : get_user_s32(val, addr)) {
        goto sigsegv_maperr;
    }

    switch (trapnr) {
    case TILEGX_EXCP_OPCODE_FETCHADD:
    case TILEGX_EXCP_OPCODE_FETCHADD4:
        valb += val;
        break;
    case TILEGX_EXCP_OPCODE_FETCHADDGEZ:
        valb += val;
        if (valb < 0) {
            write = 0;
        }
        break;
    case TILEGX_EXCP_OPCODE_FETCHADDGEZ4:
        valb += val;
        if ((int32_t)valb < 0) {
            write = 0;
        }
        break;
    case TILEGX_EXCP_OPCODE_FETCHAND:
    case TILEGX_EXCP_OPCODE_FETCHAND4:
        valb &= val;
        break;
    case TILEGX_EXCP_OPCODE_FETCHOR:
    case TILEGX_EXCP_OPCODE_FETCHOR4:
        valb |= val;
        break;
    default:
        g_assert_not_reached();
    }

    if (write) {
        if (quad ? put_user_u64(valb, addr) : put_user_u32(valb, addr)) {
            goto sigsegv_maperr;
        }
    }

    set_regval(env, env->atomic_dstr, val);
    end_exclusive();
    return;

 sigsegv_maperr:
    end_exclusive();
    gen_sigsegv_maperr(env, addr);
}

void cpu_loop(CPUTLGState *env)
{
    CPUState *cs = env_cpu(env);
    int trapnr;

    while (1) {
        cpu_exec_start(cs);
        trapnr = cpu_exec(cs);
        cpu_exec_end(cs);
        process_queued_cpu_work(cs);

        switch (trapnr) {
        case TILEGX_EXCP_SYSCALL:
        {
            abi_ulong ret = do_syscall(env, env->regs[TILEGX_R_NR],
                                       env->regs[0], env->regs[1],
                                       env->regs[2], env->regs[3],
                                       env->regs[4], env->regs[5],
                                       env->regs[6], env->regs[7]);
            if (ret == -TARGET_ERESTARTSYS) {
                env->pc -= 8;
            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
                env->regs[TILEGX_R_RE] = ret;
                env->regs[TILEGX_R_ERR] = TILEGX_IS_ERRNO(ret) ? -ret : 0;
            }
            break;
        }
        case TILEGX_EXCP_OPCODE_EXCH:
            do_exch(env, true, false);
            break;
        case TILEGX_EXCP_OPCODE_EXCH4:
            do_exch(env, false, false);
            break;
        case TILEGX_EXCP_OPCODE_CMPEXCH:
            do_exch(env, true, true);
            break;
        case TILEGX_EXCP_OPCODE_CMPEXCH4:
            do_exch(env, false, true);
            break;
        case TILEGX_EXCP_OPCODE_FETCHADD:
        case TILEGX_EXCP_OPCODE_FETCHADDGEZ:
        case TILEGX_EXCP_OPCODE_FETCHAND:
        case TILEGX_EXCP_OPCODE_FETCHOR:
            do_fetch(env, trapnr, true);
            break;
        case TILEGX_EXCP_OPCODE_FETCHADD4:
        case TILEGX_EXCP_OPCODE_FETCHADDGEZ4:
        case TILEGX_EXCP_OPCODE_FETCHAND4:
        case TILEGX_EXCP_OPCODE_FETCHOR4:
            do_fetch(env, trapnr, false);
            break;
        case TILEGX_EXCP_SIGNAL:
            do_signal(env, env->signo, env->sigcode);
            break;
        case TILEGX_EXCP_REG_IDN_ACCESS:
        case TILEGX_EXCP_REG_UDN_ACCESS:
            gen_sigill_reg(env);
            break;
        case EXCP_ATOMIC:
            cpu_exec_step_atomic(cs);
            break;
        default:
            fprintf(stderr, "trapnr is %d[0x%x].\n", trapnr, trapnr);
            g_assert_not_reached();
        }
        process_pending_signals(env);
    }
}

void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
{
    int i;
    for (i = 0; i < TILEGX_R_COUNT; i++) {
        env->regs[i] = regs->regs[i];
    }
    for (i = 0; i < TILEGX_SPR_COUNT; i++) {
        env->spregs[i] = 0;
    }
    env->pc = regs->pc;
}