1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
// See LICENSE for license details.
#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include "riscv_test.h"
void trap_entry();
void pop_tf(trapframe_t*);
void do_tohost(long tohost_value);
#define pa2kva(pa) ((void*)(pa) - MEGAPAGE_SIZE)
static uint64_t lfsr63(uint64_t x)
{
uint64_t bit = (x ^ (x >> 1)) & 1;
return (x >> 1) | (bit << 62);
}
static void cputchar(int x)
{
do_tohost(0x0101000000000000 | (unsigned char)x);
}
static void cputstring(const char* s)
{
while (*s)
cputchar(*s++);
}
static void terminate(int code)
{
do_tohost(code);
while (1);
}
#define stringify1(x) #x
#define stringify(x) stringify1(x)
#define assert(x) do { \
if (x) break; \
cputstring("Assertion failed: " stringify(x) "\n"); \
terminate(3); \
} while(0)
typedef struct { pte_t addr; void* next; } freelist_t;
pte_t l1pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
pte_t user_l2pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
pte_t user_l3pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
pte_t kernel_l2pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
pte_t kernel_l3pt[PTES_PER_PT] __attribute__((aligned(PGSIZE)));
freelist_t user_mapping[MAX_TEST_PAGES];
freelist_t freelist_nodes[MAX_TEST_PAGES];
freelist_t *freelist_head, *freelist_tail;
void printhex(uint64_t x)
{
char str[17];
for (int i = 0; i < 16; i++)
{
str[15-i] = (x & 0xF) + ((x & 0xF) < 10 ? '0' : 'a'-10);
x >>= 4;
}
str[16] = 0;
cputstring(str);
}
void evict(unsigned long addr)
{
assert(addr >= PGSIZE && addr < MAX_TEST_PAGES * PGSIZE);
addr = addr/PGSIZE*PGSIZE;
freelist_t* node = &user_mapping[addr/PGSIZE];
if (node->addr)
{
// check referenced and dirty bits
assert(user_l3pt[addr/PGSIZE] & PTE_R);
if (memcmp((void*)addr, pa2kva(addr), PGSIZE)) {
assert(user_l3pt[addr/PGSIZE] & PTE_D);
memcpy((void*)addr, pa2kva(addr), PGSIZE);
}
user_mapping[addr/PGSIZE].addr = 0;
if (freelist_tail == 0)
freelist_head = freelist_tail = node;
else
{
freelist_tail->next = node;
freelist_tail = node;
}
}
}
void handle_fault(unsigned long addr)
{
assert(addr >= PGSIZE && addr < MAX_TEST_PAGES * PGSIZE);
addr = addr/PGSIZE*PGSIZE;
freelist_t* node = freelist_head;
assert(node);
freelist_head = node->next;
if (freelist_head == freelist_tail)
freelist_tail = 0;
user_l3pt[addr/PGSIZE] = (node->addr >> PGSHIFT << PTE_PPN_SHIFT) | PTE_V | PTE_TYPE_URWX_SRW;
asm volatile ("sfence.vm");
assert(user_mapping[addr/PGSIZE].addr == 0);
user_mapping[addr/PGSIZE] = *node;
memcpy((void*)addr, pa2kva(addr), PGSIZE);
__builtin___clear_cache(0,0);
}
void handle_trap(trapframe_t* tf)
{
if (tf->cause == CAUSE_USER_ECALL)
{
int n = tf->gpr[10];
for (long i = 1; i < MAX_TEST_PAGES; i++)
evict(i*PGSIZE);
terminate(n);
}
else if (tf->cause == CAUSE_FAULT_FETCH)
handle_fault(tf->epc);
else if (tf->cause == CAUSE_ILLEGAL_INSTRUCTION)
{
assert(tf->epc % 4 == 0);
int* fssr;
asm ("jal %0, 1f; fssr x0; 1:" : "=r"(fssr));
if (*(int*)tf->epc == *fssr)
terminate(1); // FP test on non-FP hardware. "succeed."
else
assert(!"illegal instruction");
tf->epc += 4;
}
else if (tf->cause == CAUSE_FAULT_LOAD || tf->cause == CAUSE_FAULT_STORE)
handle_fault(tf->badvaddr);
else
assert(!"unexpected exception");
pop_tf(tf);
}
static void coherence_torture()
{
// cause coherence misses without affecting program semantics
uint64_t random = ENTROPY;
while (1) {
uintptr_t paddr = (random % (2 * (MAX_TEST_PAGES + 1) * PGSIZE)) & -4;
#ifdef __riscv_atomic
if (random & 1) // perform a no-op write
asm volatile ("amoadd.w zero, zero, (%0)" :: "r"(paddr));
else // perform a read
#endif
asm volatile ("lw zero, (%0)" :: "r"(paddr));
random = lfsr63(random);
}
}
void vm_boot(long test_addr, long seed)
{
if (read_csr(mhartid) > 0)
coherence_torture();
assert(SIZEOF_TRAPFRAME_T == sizeof(trapframe_t));
#if MAX_TEST_PAGES > PTES_PER_PT
# error
#endif
// map kernel to uppermost megapage
l1pt[PTES_PER_PT-1] = ((pte_t)kernel_l2pt >> PGSHIFT << PTE_PPN_SHIFT) | PTE_V | PTE_TYPE_TABLE;
kernel_l2pt[PTES_PER_PT-1] = ((pte_t)kernel_l3pt >> PGSHIFT << PTE_PPN_SHIFT) | PTE_V | PTE_TYPE_TABLE;
// map user to lowermost megapage
l1pt[0] = ((pte_t)user_l2pt >> PGSHIFT << PTE_PPN_SHIFT) | PTE_V | PTE_TYPE_TABLE;
user_l2pt[0] = ((pte_t)user_l3pt >> PGSHIFT << PTE_PPN_SHIFT) | PTE_V | PTE_TYPE_TABLE;
write_csr(sptbr, (uintptr_t)l1pt >> PGSHIFT);
// set up supervisor trap handling
write_csr(stvec, pa2kva(trap_entry));
write_csr(sscratch, pa2kva(read_csr(mscratch)));
write_csr(medeleg,
(1 << CAUSE_USER_ECALL) |
(1 << CAUSE_FAULT_FETCH) |
(1 << CAUSE_FAULT_LOAD) |
(1 << CAUSE_FAULT_STORE));
// on ERET, user mode w/interrupts on; FPU on; accelerator on; VM on
write_csr(mstatus, MSTATUS_UIE | MSTATUS_FS | MSTATUS_XS |
(VM_SV39 * (MSTATUS_VM & ~(MSTATUS_VM<<1))));
seed = 1 + (seed % MAX_TEST_PAGES);
freelist_head = pa2kva((void*)&freelist_nodes[0]);
freelist_tail = pa2kva(&freelist_nodes[MAX_TEST_PAGES-1]);
for (long i = 0; i < MAX_TEST_PAGES; i++)
{
freelist_nodes[i].addr = (MAX_TEST_PAGES + seed)*PGSIZE;
freelist_nodes[i].next = pa2kva(&freelist_nodes[i+1]);
seed = LFSR_NEXT(seed);
kernel_l3pt[i] = (i << PTE_PPN_SHIFT) | PTE_V | PTE_TYPE_SRWX;
}
freelist_nodes[MAX_TEST_PAGES-1].next = 0;
trapframe_t tf;
memset(&tf, 0, sizeof(tf));
write_csr(mepc, test_addr);
pop_tf(&tf);
}
|
