env/v/vm.c

   1 #include <stdint.h>
   2 #include <string.h>
   3 #include <stdio.h>
   4
   5 #include "riscv_test.h"
   6
   7 void trap_entry();
   8 void pop_tf(trapframe_t*);
   9
  10 static void cputchar(int x)
  11 {
  12   while (mtpcr(PCR_TOHOST, 0x0101000000000000 | (unsigned char)x));
  13 }
  14
  15 static void cputstring(const char* s)
  16 {
  17   while(*s)
  18     cputchar(*s++);
  19   cputchar('\n');
  20 }
  21
  22 static void terminate(int code)
  23 {
  24   while (mtpcr(PCR_TOHOST, code));
  25   while (1);
  26 }
  27
  28 #define stringify1(x) #x
  29 #define stringify(x) stringify1(x)
  30 #define assert(x) do { \
  31   if (x) break; \
  32   cputstring("Assertion failed: " stringify(x)); \
  33   terminate(3); \
  34 } while(0)
  35
  36 #define RELOC(x) ((typeof(x))((char*)(x) + (PGSIZE*MAX_TEST_PAGES)))
  37
  38 typedef struct { pte_t addr; void* next; } freelist_t;
  39
  40 pte_t l1pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
  41 pte_t l2pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
  42 pte_t l3pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
  43 freelist_t user_mapping[MAX_TEST_PAGES];
  44 freelist_t freelist_nodes[MAX_TEST_PAGES];
  45 freelist_t *freelist_head, *freelist_tail;
  46
  47 void printhex(uint64_t x)
  48 {
  49   char str[17];
  50   for (int i = 0; i < 16; i++)
  51   {
  52     str[15-i] = (x & 0xF) + ((x & 0xF) < 10 ? '0' : 'a'-10);
  53     x >>= 4;
  54   }
  55   str[16] = 0;
  56
  57   cputstring(str);
  58 }
  59
  60 void evict(unsigned long addr)
  61 {
  62   assert(addr >= PGSIZE && addr < RELOC(0L));
  63   addr = addr/PGSIZE*PGSIZE;
  64
  65   freelist_t* node = RELOC(&user_mapping[addr/PGSIZE]);
  66   if (node->addr)
  67   {
  68     memcpy((void*)RELOC(addr), (void*)addr, PGSIZE);
  69     RELOC(&user_mapping[addr/PGSIZE])->addr = 0;
  70
  71     if (*RELOC(&freelist_tail) == 0)
  72       *RELOC(&freelist_head) = *RELOC(&freelist_tail) = node;
  73     else
  74     {
  75       (*RELOC(&freelist_tail))->next = node;
  76       *RELOC(&freelist_tail) = node;
  77     }
  78   }
  79 }
  80
  81 void handle_fault(unsigned long addr)
  82 {
  83   assert(addr >= PGSIZE && addr < RELOC(0L));
  84   addr = addr/PGSIZE*PGSIZE;
  85
  86   freelist_t* node = *RELOC(&freelist_head);
  87   assert(node);
  88   *RELOC(&freelist_head) = node->next;
  89   if (*RELOC(&freelist_head) == *RELOC(&freelist_tail))
  90     *RELOC(&freelist_tail) = 0;
  91
  92   *RELOC(&l3pt[addr/PGSIZE]) = node->addr | PTE_UW | PTE_UR | PTE_UX | PTE_SW | PTE_SR | PTE_SX | PTE_V;
  93   mtpcr(PCR_FATC, 0);
  94
  95   assert(RELOC(&user_mapping[addr/PGSIZE])->addr == 0);
  96   *RELOC(&user_mapping[addr/PGSIZE]) = *node;
  97   memcpy((void*)addr, (void*)RELOC(addr), PGSIZE);
  98
  99   __builtin___clear_cache(0,0);
 100 }
 101
 102 void emulate_vxcptsave(trapframe_t* tf)
 103 {
 104   long where = tf->gpr[(tf->insn >> 22) & 0x1F];
 105
 106   asm volatile ("vxcptevac %0" : : "r"(where));
 107   fencevl();
 108 }
 109
 110 void do_vxcptrestore(long* where)
 111 {
 112   vxcpthold();
 113
 114   int idx = 0;
 115   long dword, cmd, pf;
 116   int first = 1;
 117
 118   while (1)
 119   {
 120     dword = where[idx++];
 121
 122     if (dword < 0) break;
 123
 124     if (dword_bit_cnt(dword))
 125     {
 126       venqcnt(dword, pf | (dword_bit_cmd(where[idx]) << 1));
 127     }
 128     else
 129     {
 130       if (!first)
 131       {
 132         venqcmd(cmd, pf);
 133       }
 134
 135       first = 0;
 136       cmd = dword;
 137       pf = dword_bit_pf(cmd);
 138
 139       if (dword_bit_imm1(cmd))
 140       {
 141         venqimm1(where[idx++], pf);
 142       }
 143       if (dword_bit_imm2(cmd))
 144       {
 145         venqimm2(where[idx++], pf);
 146       }
 147     }
 148   }
 149   if (!first)
 150   {
 151     venqcmd(cmd, pf);
 152   }
 153 }
 154
 155 void emulate_vxcptrestore(trapframe_t* tf)
 156 {
 157   long* where = (long*)tf->gpr[(tf->insn >> 22) & 0x1F];
 158   vxcptkill();
 159   vcfg(tf->veccfg);
 160   do_vxcptrestore(where);
 161 }
 162
 163 void restore_vector(trapframe_t* tf)
 164 {
 165   mtpcr(PCR_VECBANK, tf->vecbank);
 166   vcfg(tf->veccfg);
 167
 168   if (mfpcr(PCR_IMPL) == IMPL_ROCKET)
 169     do_vxcptrestore(tf->evac);
 170   else
 171     asm volatile("vxcptrestore %0" : : "r"(tf->evac) : "memory");
 172 }
 173
 174 void handle_trap(trapframe_t* tf)
 175 {
 176   if (tf->cause == CAUSE_SYSCALL)
 177   {
 178     int n = tf->gpr[18];
 179
 180     for (long i = 1; i < MAX_TEST_PAGES; i++)
 181       evict(i*PGSIZE);
 182
 183     terminate(n);
 184   }
 185   else if (tf->cause == CAUSE_FAULT_FETCH)
 186     handle_fault(tf->epc);
 187   else if (tf->cause == CAUSE_ILLEGAL_INSTRUCTION)
 188   {
 189     int fssr;
 190     asm ("la %0, 1f; lw %0, 0(%0); b 2f; 1: fssr x0; 2:" : "=r"(fssr));
 191
 192     if (tf->insn == fssr)
 193       terminate(1); // FP test on non-FP hardware.  "succeed."
 194     else if ((tf->insn & 0xF83FFFFF) == 0x37B)
 195       emulate_vxcptsave(tf);
 196     else if ((tf->insn & 0xF83FFFFF) == 0x77B)
 197       emulate_vxcptrestore(tf);
 198     else
 199       assert(0);
 200     tf->epc += 4;
 201   }
 202   else if (tf->cause == CAUSE_FAULT_LOAD || tf->cause == CAUSE_FAULT_STORE ||
 203            tf->cause == CAUSE_VECTOR_FAULT_LOAD || tf->cause == CAUSE_VECTOR_FAULT_STORE ||
 204            tf->cause == CAUSE_VECTOR_FAULT_FETCH)
 205     handle_fault(tf->badvaddr);
 206   else
 207     assert(0);
 208
 209 out:
 210   if (!(tf->sr & SR_PS) && (tf->sr & SR_EV))
 211     restore_vector(tf);
 212   pop_tf(tf);
 213 }
 214
 215 void vm_boot(long test_addr, long seed)
 216 {
 217   while (mfpcr(PCR_HARTID) > 0); // only core 0 proceeds
 218
 219   assert(SIZEOF_TRAPFRAME_T == sizeof(trapframe_t));
 220
 221   seed = 1 + (seed % MAX_TEST_PAGES);
 222   freelist_head = RELOC(&freelist_nodes[0]);
 223   freelist_tail = RELOC(&freelist_nodes[MAX_TEST_PAGES-1]);
 224   for (long i = 0; i < MAX_TEST_PAGES; i++)
 225   {
 226     freelist_nodes[i].addr = (MAX_TEST_PAGES+i)*PGSIZE;
 227     freelist_nodes[i].next = RELOC(&freelist_nodes[i+1]);
 228     seed = LFSR_NEXT(seed);
 229   }
 230   freelist_nodes[MAX_TEST_PAGES-1].next = 0;
 231
 232   assert(MAX_TEST_PAGES*2 < PTES_PER_PT);
 233   l1pt[0] = (pte_t)l2pt | PTE_V | PTE_T;
 234   l2pt[0] = (pte_t)l3pt | PTE_V | PTE_T;
 235   for (long i = 0; i < MAX_TEST_PAGES; i++)
 236     l3pt[i] = l3pt[i+MAX_TEST_PAGES] = (i*PGSIZE) | PTE_SW | PTE_SR | PTE_SX | PTE_V;
 237
 238   mtpcr(PCR_PTBR, l1pt);
 239   mtpcr(PCR_SR, mfpcr(PCR_SR) | SR_VM | SR_EF);
 240
 241   // relocate
 242   long adjustment = RELOC(0L), tmp;
 243   mtpcr(PCR_EVEC, (char*)&trap_entry + adjustment);
 244   asm volatile ("add sp, sp, %1; rdpc %0; addi %0, %0, 16; add %0, %0, %1; jr %0" : "=&r"(tmp) : "r"(adjustment));
 245
 246   memset(RELOC(&l3pt[0]), 0, MAX_TEST_PAGES*sizeof(pte_t));
 247   mtpcr(PCR_FATC, 0);
 248
 249   trapframe_t tf;
 250   memset(&tf, 0, sizeof(tf));
 251   tf.sr = SR_EF | SR_EV | SR_S | SR_U64 | SR_S64 | SR_VM;
 252   tf.epc = test_addr;
 253
 254   pop_tf(&tf);
 255 }