handle RISC-V keyboard interrupts properly
[akaros.git] / kern / arch / riscv / trap.c
1 #include <arch/arch.h>
2 #include <assert.h>
3 #include <arch/trap.h>
4 #include <arch/console.h>
5 #include <console.h>
6 #include <string.h>
7 #include <process.h>
8 #include <syscall.h>
9 #include <monitor.h>
10 #include <manager.h>
11 #include <stdio.h>
12 #include <smp.h>
13 #include <slab.h>
14 #include <mm.h>
15 #include <umem.h>
16 #include <pmap.h>
17
18 /* These are the stacks the kernel will load when it receives a trap from user
19  * space.  The deal is that they get set right away in entry.S, and can always
20  * be used for finding the top of the stack (from which you should subtract the
21  * sizeof the trapframe.  Note, we need to have a junk value in the array so
22  * that this is NOT part of the BSS.  If it is in the BSS, it will get 0'd in
23  * kernel_init(), which is after these values get set.
24  *
25  * TODO: if these end up becoming contended cache lines, move this to
26  * per_cpu_info. */
27 uintptr_t core_stacktops[MAX_NUM_CPUS] = {0xcafebabe, 0};
28
29 void
30 advance_pc(trapframe_t* state)
31 {
32         state->epc += 4;
33 }
34
35 /* Set stacktop for the current core to be the stack the kernel will start on
36  * when trapping/interrupting from userspace */
37 void set_stack_top(uintptr_t stacktop)
38 {
39         core_stacktops[core_id()] = stacktop;
40 }
41
42 /* Note the assertion assumes we are in the top page of the stack. */
43 uintptr_t get_stack_top(void)
44 {
45         register uintptr_t sp asm ("sp");
46         uintptr_t stacktop = core_stacktops[core_id()];
47         assert(ROUNDUP(sp, PGSIZE) == stacktop);
48         return stacktop;
49 }
50
51 void
52 idt_init(void)
53 {
54 }
55
56 void
57 sysenter_init(void)
58 {
59 }
60
61 /* Helper.  For now, this copies out the TF to pcpui, and sets cur_tf to point
62  * to it. */
63 static void
64 set_current_tf(struct per_cpu_info *pcpui, struct trapframe *tf)
65 {
66         if (irq_is_enabled())
67                 warn("Turn off IRQs until cur_tf is set!");
68         assert(!pcpui->cur_tf);
69         pcpui->actual_tf = *tf;
70         pcpui->cur_tf = &pcpui->actual_tf;
71 }
72
73 static int
74 format_trapframe(trapframe_t *tf, char* buf, int bufsz)
75 {
76         // slightly hackish way to read out the instruction that faulted.
77         // not guaranteed to be right 100% of the time
78         uint32_t insn;
79         if(!(current && !memcpy_from_user(current,&insn,(void*)tf->epc,4)))
80                 insn = -1;
81
82         int len = snprintf(buf,bufsz,"TRAP frame at %p on core %d\n",
83                            tf, core_id());
84         static const char* regnames[] = {
85           "z ", "ra", "v0", "v1", "a0", "a1", "a2", "a3",
86           "a4", "a5", "a6", "a7", "t0", "t1", "t2", "t3",
87           "t4", "t5", "t6", "t7", "s0", "s1", "s2", "s3",
88           "s4", "s5", "s6", "s7", "s8", "fp", "sp", "tp"
89         };
90         
91         tf->gpr[0] = 0;
92         
93         for(int i = 0; i < 32; i+=4)
94         {
95                 for(int j = 0; j < 4; j++)
96                         len += snprintf(buf+len, bufsz-len,
97                                         "%s %016lx%c", regnames[i+j], tf->gpr[i+j], 
98                                         j < 3 ? ' ' : '\n');
99         }
100         len += snprintf(buf+len, bufsz-len,
101                         "sr %016lx pc %016lx va %016lx insn       %08x\n",
102                                         tf->sr, tf->epc, tf->badvaddr, insn);
103
104         buf[bufsz-1] = 0;
105         return len;
106 }
107
108 void
109 print_trapframe(trapframe_t* tf)
110 {
111         char buf[1024];
112         int len = format_trapframe(tf,buf,sizeof(buf));
113         cputbuf(buf,len);
114 }
115
116 static void exit_halt_loop(trapframe_t* tf)
117 {
118         extern char after_cpu_halt;
119         if ((char*)tf->epc >= (char*)&cpu_halt && (char*)tf->epc < &after_cpu_halt)
120                 tf->epc = tf->gpr[1];
121 }
122
123 static void handle_keypress(char c)
124 {
125         amr_t handler = c == 'G' ? __run_mon : __cons_add_char;
126         send_kernel_message(core_id(), handler, (long)&cons_buf, (long)c, 0,
127                             KMSG_ROUTINE);
128         cons_init();
129 }
130
131 static void handle_host_interrupt(trapframe_t* tf)
132 {
133         uintptr_t fh = mtpcr(PCR_FROMHOST, 0);
134         switch (fh >> 56)
135         {
136           case 0x01: handle_keypress(fh); return;
137           default: assert(0);
138         }
139 }
140
141 static void handle_timer_interrupt(trapframe_t* tf)
142 {
143         timer_interrupt(tf, NULL);
144 }
145
146 /* Assumes that any IPI you get is really a kernel message */
147 static void handle_interprocessor_interrupt(trapframe_t* tf)
148 {
149         clear_ipi();
150         handle_kmsg_ipi(tf, 0);
151 }
152
153 static void
154 unhandled_trap(trapframe_t* state, const char* name)
155 {
156         static spinlock_t screwup_lock = SPINLOCK_INITIALIZER;
157         spin_lock(&screwup_lock);
158
159         if(in_kernel(state))
160         {
161                 print_trapframe(state);
162                 panic("Unhandled trap in kernel!\nTrap type: %s", name);
163         }
164         else
165         {
166                 char tf_buf[1024];
167                 format_trapframe(state, tf_buf, sizeof(tf_buf));
168
169                 warn("Unhandled trap in user!\nTrap type: %s\n%s", name, tf_buf);
170                 backtrace();
171                 spin_unlock(&screwup_lock);
172
173                 assert(current);
174                 enable_irq();
175                 proc_destroy(current);
176         }
177 }
178
179 static void
180 handle_misaligned_fetch(trapframe_t* state)
181 {
182         unhandled_trap(state, "Misaligned Fetch");
183 }
184
185 static void
186 handle_misaligned_load(trapframe_t* state)
187 {
188         unhandled_trap(state, "Misaligned Load");
189 }
190
191 static void
192 handle_misaligned_store(trapframe_t* state)
193 {
194         unhandled_trap(state, "Misaligned Store");
195 }
196
197 static void
198 handle_fault_fetch(trapframe_t* state)
199 {
200         if(in_kernel(state))
201         {
202                 print_trapframe(state);
203                 panic("Instruction Page Fault in the Kernel at %p!", state->epc);
204         }
205
206         set_current_tf(&per_cpu_info[core_id()], state);
207
208         if(handle_page_fault(current, state->epc, PROT_EXEC))
209                 unhandled_trap(state, "Instruction Page Fault");
210 }
211
212 static void
213 handle_fault_load(trapframe_t* state)
214 {
215         if(in_kernel(state))
216         {
217                 print_trapframe(state);
218                 panic("Load Page Fault in the Kernel at %p!", state->badvaddr);
219         }
220
221         set_current_tf(&per_cpu_info[core_id()], state);
222
223         if(handle_page_fault(current, state->badvaddr, PROT_READ))
224                 unhandled_trap(state, "Load Page Fault");
225 }
226
227 static void
228 handle_fault_store(trapframe_t* state)
229 {
230         if(in_kernel(state))
231         {
232                 print_trapframe(state);
233                 panic("Store Page Fault in the Kernel at %p!", state->badvaddr);
234         }
235
236         set_current_tf(&per_cpu_info[core_id()], state);
237
238         if(handle_page_fault(current, state->badvaddr, PROT_WRITE))
239                 unhandled_trap(state, "Store Page Fault");
240 }
241
242 static void
243 handle_illegal_instruction(trapframe_t* state)
244 {
245         assert(!in_kernel(state));
246
247         struct per_cpu_info *pcpui = &per_cpu_info[core_id()];
248         set_current_tf(pcpui, state);
249         if (emulate_fpu(state) == 0)
250         {
251                 advance_pc(pcpui->cur_tf);
252                 return;
253         }
254
255         unhandled_trap(state, "Illegal Instruction");
256 }
257
258 static void
259 handle_fp_disabled(trapframe_t* tf)
260 {
261         if(in_kernel(tf))
262                 panic("kernel executed an FP instruction!");
263
264         tf->sr |= SR_EF;
265         env_pop_tf(tf); /* We didn't save our TF, so don't use proc_restartcore */
266 }
267
268 static void
269 handle_syscall(trapframe_t* state)
270 {
271         uintptr_t a0 = state->gpr[4];
272         uintptr_t a1 = state->gpr[5];
273
274         advance_pc(state);
275         set_current_tf(&per_cpu_info[core_id()], state);
276         enable_irq();
277         prep_syscalls(current, (struct syscall*)a0, a1);
278 }
279
280 static void
281 handle_breakpoint(trapframe_t* state)
282 {
283         advance_pc(state);
284         monitor(state);
285 }
286
287 void
288 handle_trap(trapframe_t* tf)
289 {
290         static void (*const trap_handlers[])(trapframe_t*) = {
291           [CAUSE_MISALIGNED_FETCH] = handle_misaligned_fetch,
292           [CAUSE_FAULT_FETCH] = handle_fault_fetch,
293           [CAUSE_ILLEGAL_INSTRUCTION] = handle_illegal_instruction,
294           [CAUSE_PRIVILEGED_INSTRUCTION] = handle_illegal_instruction,
295           [CAUSE_FP_DISABLED] = handle_fp_disabled,
296           [CAUSE_SYSCALL] = handle_syscall,
297           [CAUSE_BREAKPOINT] = handle_breakpoint,
298           [CAUSE_MISALIGNED_LOAD] = handle_misaligned_load,
299           [CAUSE_MISALIGNED_STORE] = handle_misaligned_store,
300           [CAUSE_FAULT_LOAD] = handle_fault_load,
301           [CAUSE_FAULT_STORE] = handle_fault_store,
302         };
303
304         static void (*const irq_handlers[])(trapframe_t*) = {
305           [IRQ_TIMER] = handle_timer_interrupt,
306           [IRQ_HOST] = handle_host_interrupt,
307           [IRQ_IPI] = handle_interprocessor_interrupt,
308         };
309         
310         struct per_cpu_info *pcpui = &per_cpu_info[core_id()];
311         if (tf->cause < 0)
312         {
313                 uint8_t irq = tf->cause;
314                 assert(irq < sizeof(irq_handlers)/sizeof(irq_handlers[0]) &&
315                        irq_handlers[irq]);
316
317                 if (in_kernel(tf))
318                         exit_halt_loop(tf);
319                 else
320                         set_current_tf(&per_cpu_info[core_id()], tf);
321
322                 inc_irq_depth(pcpui);
323                 irq_handlers[irq](tf);
324                 dec_irq_depth(pcpui);
325         }
326         else
327         {
328                 assert(tf->cause < sizeof(trap_handlers)/sizeof(trap_handlers[0]) &&
329                        trap_handlers[tf->cause]);
330                 if (in_kernel(tf)) {
331                         inc_ktrap_depth(pcpui);
332                         trap_handlers[tf->cause](tf);
333                         dec_ktrap_depth(pcpui);
334                 } else {
335                         trap_handlers[tf->cause](tf);
336                 }
337         }
338         
339         /* Return to the current process, which should be runnable.  If we're the
340          * kernel, we should just return naturally.  Note that current and tf need
341          * to still be okay (might not be after blocking) */
342         if (in_kernel(tf))
343                 env_pop_tf(tf);
344         else
345                 proc_restartcore();
346 }
347
348 /* We don't have NMIs now. */
349 void send_nmi(uint32_t os_coreid)
350 {
351 }