target/xtensa/win_helper.c

   1 /*
   2  * Copyright (c) 2011 - 2019, Max Filippov, Open Source and Linux Lab.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are met:
   7  *     * Redistributions of source code must retain the above copyright
   8  *       notice, this list of conditions and the following disclaimer.
   9  *     * Redistributions in binary form must reproduce the above copyright
  10  *       notice, this list of conditions and the following disclaimer in the
  11  *       documentation and/or other materials provided with the distribution.
  12  *     * Neither the name of the Open Source and Linux Lab nor the
  13  *       names of its contributors may be used to endorse or promote products
  14  *       derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  25  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "qemu/osdep.h"
  29 #include "qemu/main-loop.h"
  30 #include "cpu.h"
  31 #include "exec/helper-proto.h"
  32 #include "qemu/host-utils.h"
  33 #include "exec/exec-all.h"
  34
  35 static void copy_window_from_phys(CPUXtensaState *env,
  36                                   uint32_t window, uint32_t phys, uint32_t n)
  37 {
  38     assert(phys < env->config->nareg);
  39     if (phys + n <= env->config->nareg) {
  40         memcpy(env->regs + window, env->phys_regs + phys,
  41                n * sizeof(uint32_t));
  42     } else {
  43         uint32_t n1 = env->config->nareg - phys;
  44         memcpy(env->regs + window, env->phys_regs + phys,
  45                n1 * sizeof(uint32_t));
  46         memcpy(env->regs + window + n1, env->phys_regs,
  47                (n - n1) * sizeof(uint32_t));
  48     }
  49 }
  50
  51 static void copy_phys_from_window(CPUXtensaState *env,
  52                                   uint32_t phys, uint32_t window, uint32_t n)
  53 {
  54     assert(phys < env->config->nareg);
  55     if (phys + n <= env->config->nareg) {
  56         memcpy(env->phys_regs + phys, env->regs + window,
  57                n * sizeof(uint32_t));
  58     } else {
  59         uint32_t n1 = env->config->nareg - phys;
  60         memcpy(env->phys_regs + phys, env->regs + window,
  61                n1 * sizeof(uint32_t));
  62         memcpy(env->phys_regs, env->regs + window + n1,
  63                (n - n1) * sizeof(uint32_t));
  64     }
  65 }
  66
  67 static inline unsigned windowbase_bound(unsigned a, const CPUXtensaState *env)
  68 {
  69     return a & (env->config->nareg / 4 - 1);
  70 }
  71
  72 static inline unsigned windowstart_bit(unsigned a, const CPUXtensaState *env)
  73 {
  74     return 1 << windowbase_bound(a, env);
  75 }
  76
  77 void xtensa_sync_window_from_phys(CPUXtensaState *env)
  78 {
  79     copy_window_from_phys(env, 0, env->sregs[WINDOW_BASE] * 4, 16);
  80 }
  81
  82 void xtensa_sync_phys_from_window(CPUXtensaState *env)
  83 {
  84     copy_phys_from_window(env, env->sregs[WINDOW_BASE] * 4, 0, 16);
  85 }
  86
  87 static void xtensa_rotate_window_abs(CPUXtensaState *env, uint32_t position)
  88 {
  89     xtensa_sync_phys_from_window(env);
  90     env->sregs[WINDOW_BASE] = windowbase_bound(position, env);
  91     xtensa_sync_window_from_phys(env);
  92 }
  93
  94 void xtensa_rotate_window(CPUXtensaState *env, uint32_t delta)
  95 {
  96     xtensa_rotate_window_abs(env, env->sregs[WINDOW_BASE] + delta);
  97 }
  98
  99 void HELPER(wsr_windowbase)(CPUXtensaState *env, uint32_t v)
 100 {
 101     xtensa_rotate_window_abs(env, v);
 102 }
 103
 104 void HELPER(entry)(CPUXtensaState *env, uint32_t pc, uint32_t s, uint32_t imm)
 105 {
 106     int callinc = (env->sregs[PS] & PS_CALLINC) >> PS_CALLINC_SHIFT;
 107
 108     env->regs[(callinc << 2) | (s & 3)] = env->regs[s] - imm;
 109     xtensa_rotate_window(env, callinc);
 110     env->sregs[WINDOW_START] |=
 111         windowstart_bit(env->sregs[WINDOW_BASE], env);
 112 }
 113
 114 void HELPER(window_check)(CPUXtensaState *env, uint32_t pc, uint32_t w)
 115 {
 116     uint32_t windowbase = windowbase_bound(env->sregs[WINDOW_BASE], env);
 117     uint32_t windowstart = xtensa_replicate_windowstart(env) >>
 118         (env->sregs[WINDOW_BASE] + 1);
 119     uint32_t n = ctz32(windowstart) + 1;
 120
 121     assert(n <= w);
 122
 123     xtensa_rotate_window(env, n);
 124     env->sregs[PS] = (env->sregs[PS] & ~PS_OWB) |
 125         (windowbase << PS_OWB_SHIFT) | PS_EXCM;
 126     env->sregs[EPC1] = env->pc = pc;
 127
 128     switch (ctz32(windowstart >> n)) {
 129     case 0:
 130         HELPER(exception)(env, EXC_WINDOW_OVERFLOW4);
 131         break;
 132     case 1:
 133         HELPER(exception)(env, EXC_WINDOW_OVERFLOW8);
 134         break;
 135     default:
 136         HELPER(exception)(env, EXC_WINDOW_OVERFLOW12);
 137         break;
 138     }
 139 }
 140
 141 void HELPER(test_ill_retw)(CPUXtensaState *env, uint32_t pc)
 142 {
 143     int n = (env->regs[0] >> 30) & 0x3;
 144     int m = 0;
 145     uint32_t windowbase = windowbase_bound(env->sregs[WINDOW_BASE], env);
 146     uint32_t windowstart = env->sregs[WINDOW_START];
 147
 148     if (windowstart & windowstart_bit(windowbase - 1, env)) {
 149         m = 1;
 150     } else if (windowstart & windowstart_bit(windowbase - 2, env)) {
 151         m = 2;
 152     } else if (windowstart & windowstart_bit(windowbase - 3, env)) {
 153         m = 3;
 154     }
 155
 156     if (n == 0 || (m != 0 && m != n)) {
 157         qemu_log_mask(LOG_GUEST_ERROR, "Illegal retw instruction(pc = %08x), "
 158                       "PS = %08x, m = %d, n = %d\n",
 159                       pc, env->sregs[PS], m, n);
 160         HELPER(exception_cause)(env, pc, ILLEGAL_INSTRUCTION_CAUSE);
 161     }
 162 }
 163
 164 void HELPER(test_underflow_retw)(CPUXtensaState *env, uint32_t pc)
 165 {
 166     int n = (env->regs[0] >> 30) & 0x3;
 167
 168     if (!(env->sregs[WINDOW_START] &
 169           windowstart_bit(env->sregs[WINDOW_BASE] - n, env))) {
 170         uint32_t windowbase = windowbase_bound(env->sregs[WINDOW_BASE], env);
 171
 172         xtensa_rotate_window(env, -n);
 173         /* window underflow */
 174         env->sregs[PS] = (env->sregs[PS] & ~PS_OWB) |
 175             (windowbase << PS_OWB_SHIFT) | PS_EXCM;
 176         env->sregs[EPC1] = env->pc = pc;
 177
 178         if (n == 1) {
 179             HELPER(exception)(env, EXC_WINDOW_UNDERFLOW4);
 180         } else if (n == 2) {
 181             HELPER(exception)(env, EXC_WINDOW_UNDERFLOW8);
 182         } else if (n == 3) {
 183             HELPER(exception)(env, EXC_WINDOW_UNDERFLOW12);
 184         }
 185     }
 186 }
 187
 188 uint32_t HELPER(retw)(CPUXtensaState *env, uint32_t pc)
 189 {
 190     int n = (env->regs[0] >> 30) & 0x3;
 191     uint32_t windowbase = windowbase_bound(env->sregs[WINDOW_BASE], env);
 192     uint32_t ret_pc = (pc & 0xc0000000) | (env->regs[0] & 0x3fffffff);
 193
 194     xtensa_rotate_window(env, -n);
 195     env->sregs[WINDOW_START] &= ~windowstart_bit(windowbase, env);
 196     return ret_pc;
 197 }
 198
 199 void HELPER(rotw)(CPUXtensaState *env, uint32_t imm4)
 200 {
 201     xtensa_rotate_window(env, imm4);
 202 }
 203
 204 void xtensa_restore_owb(CPUXtensaState *env)
 205 {
 206     xtensa_rotate_window_abs(env, (env->sregs[PS] & PS_OWB) >> PS_OWB_SHIFT);
 207 }
 208
 209 void HELPER(restore_owb)(CPUXtensaState *env)
 210 {
 211     xtensa_restore_owb(env);
 212 }
 213
 214 void HELPER(movsp)(CPUXtensaState *env, uint32_t pc)
 215 {
 216     if ((env->sregs[WINDOW_START] &
 217          (windowstart_bit(env->sregs[WINDOW_BASE] - 3, env) |
 218           windowstart_bit(env->sregs[WINDOW_BASE] - 2, env) |
 219           windowstart_bit(env->sregs[WINDOW_BASE] - 1, env))) == 0) {
 220         HELPER(exception_cause)(env, pc, ALLOCA_CAUSE);
 221     }
 222 }