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source: trunk/hal/tsar_mips32/core/hal_exception.c @ 587

Last change on this file since 587 was 587, checked in by alain, 5 years ago
Modify the GPT (Generic Page Table) API to support remote accesses, in order to improve page faults and COW handling.
File size: 19.7 KB

Line
1	/*
2	* hal_exception.c - implementation of exception handler for TSAR-MIPS32.
3	*
4	* Author Alain Greiner (2016, 2017)
5	*
6	* Copyright (c) UPMC Sorbonne Universites
7	*
8	* This file is part of ALMOS-MKH.
9	*
10	* ALMOS-MKH is free software; you can redistribute it and/or modify it
11	* under the terms of the GNU General Public License as published by
12	* the Free Software Foundation; version 2.0 of the License.
13	*
14	* ALMOS-MKH is distributed in the hope that it will be useful, but
15	* WITHOUT ANY WARRANTY; without even the implied warranty of
16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17	* General Public License for more details.
18	*
19	* You should have received a copy of the GNU General Public License
20	* along with ALMOS-MKH; if not, write to the Free Software Foundation,
21	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22	*/
23
24	#include <hal_kernel_types.h>
25	#include <hal_irqmask.h>
26	#include <hal_special.h>
27	#include <hal_exception.h>
28	#include <thread.h>
29	#include <printk.h>
30	#include <chdev.h>
31	#include <vmm.h>
32	#include <errno.h>
33	#include <scheduler.h>
34	#include <core.h>
35	#include <syscalls.h>
36	#include <shared_syscalls.h>
37	#include <remote_busylock.h>
38	#include <hal_kentry.h>
39	#include <hal_exception.h>
40
41	//////////////////////////////////////////////////////////////////////////////////////////
42	// Extern global variables
43	//////////////////////////////////////////////////////////////////////////////////////////
44
45	extern chdev_directory_t chdev_dir; // allocated in the kernel_init.c file.
46
47	//////////////////////////////////////////////////////////////////////////////////////////
48	// This enum defines the mask values for an MMU exception code reported by the mips32.
49	//////////////////////////////////////////////////////////////////////////////////////////
50
51	typedef enum
52	{
53	MMU_WRITE_PT1_UNMAPPED = 0x0001,
54	MMU_WRITE_PT2_UNMAPPED = 0x0002,
55	MMU_WRITE_PRIVILEGE_VIOLATION = 0x0004,
56	MMU_WRITE_ACCESS_VIOLATION = 0x0008,
57	MMU_WRITE_UNDEFINED_XTN = 0x0020,
58	MMU_WRITE_PT1_ILLEGAL_ACCESS = 0x0040,
59	MMU_WRITE_PT2_ILLEGAL_ACCESS = 0x0080,
60	MMU_WRITE_DATA_ILLEGAL_ACCESS = 0x0100,
61
62	MMU_READ_PT1_UNMAPPED = 0x1001,
63	MMU_READ_PT2_UNMAPPED = 0x1002,
64	MMU_READ_PRIVILEGE_VIOLATION = 0x1004,
65	MMU_READ_EXEC_VIOLATION = 0x1010,
66	MMU_READ_UNDEFINED_XTN = 0x1020,
67	MMU_READ_PT1_ILLEGAL_ACCESS = 0x1040,
68	MMU_READ_PT2_ILLEGAL_ACCESS = 0x1080,
69	MMU_READ_DATA_ILLEGAL_ACCESS = 0x1100,
70	}
71	mmu_exception_subtype_t;
72
73	//////////////////////////////////////////////////////////////////////////////////////////
74	// This enum defines the relevant values for XCODE field in mips32 CP0_CR register.
75	//////////////////////////////////////////////////////////////////////////////////////////
76
77	typedef enum
78	{
79	XCODE_ADEL = 0x4, // Illegal address for data load
80	XCODE_ADES = 0x5, // Illegal address for data store
81	XCODE_IBE = 0x6, // Instruction MMU exception (can be NON-FATAL)
82	XCODE_DBE = 0x7, // Data MMU exception (can be NON-FATAL)
83	XCODE_RI = 0xA, // Reserved instruction exception
84	XCODE_CPU = 0xB, // Coprocessor unusable exception (can be NON-FATAl)
85	XCODE_OVR = 0xC, // Arithmetic Overflow exception
86	}
87	xcode_values_t;
88
89	/////////////////////////////////////////////
90	char * hal_mmu_exception_str( uint32_t code )
91	{
92	switch (code) {
93	case (MMU_WRITE_PT1_UNMAPPED): return "WRITE_PT1_UNMAPPED";
94	case (MMU_WRITE_PT2_UNMAPPED): return "WRITE_PT2_UNMAPPED";
95	case (MMU_WRITE_PRIVILEGE_VIOLATION): return "WRITE_PRIVILEGE_VIOLATION";
96	case (MMU_WRITE_ACCESS_VIOLATION): return "WRITE_ACCESS_VIOLATION";
97	case (MMU_WRITE_UNDEFINED_XTN): return "WRITE_UNDEFINED_XTN";
98	case (MMU_WRITE_PT1_ILLEGAL_ACCESS): return "WRITE_PT1_ILLEGAL_ACCESS";
99	case (MMU_WRITE_PT2_ILLEGAL_ACCESS): return "WRITE_PT2_ILLEGAL_ACCESS";
100	case (MMU_WRITE_DATA_ILLEGAL_ACCESS): return "WRITE_DATA_ILLEGAL_ACCESS";
101	case (MMU_READ_PT1_UNMAPPED): return "READ_PT1_UNMAPPED";
102	case (MMU_READ_PT2_UNMAPPED): return "READ_PT2_UNMAPPED";
103	case (MMU_READ_PRIVILEGE_VIOLATION): return "READ_PRIVILEGE_VIOLATION";
104	case (MMU_READ_EXEC_VIOLATION): return "READ_EXEC_VIOLATION";
105	case (MMU_READ_UNDEFINED_XTN): return "READ_UNDEFINED_XTN";
106	case (MMU_READ_PT1_ILLEGAL_ACCESS): return "READ_PT1_ILLEGAL_ACCESS";
107	case (MMU_READ_PT2_ILLEGAL_ACCESS): return "READ_PT2_ILLEGAL_ACCESS";
108	case (MMU_READ_DATA_ILLEGAL_ACCESS): return "READ_DATA_ILLEGAL_ACCESS";
109	default: return "undefined";
110	}
111	}
112
113	//////////////////////////////////////////////////////////////////////////////////////////
114	// This function is called when a FPU Coprocessor Unavailable exception has been
115	// detected for the calling thread.
116	// It enables the FPU, It saves the current FPU context in the current owner thread
117	// descriptor if required, and restore the FPU context from the calling thread descriptor.
118	//////////////////////////////////////////////////////////////////////////////////////////
119	// @ this : pointer on faulty thread descriptor.
120	// @ return always EXCP_NON_FATAL
121	//////////////////////////////////////////////////////////////////////////////////////////
122	error_t hal_fpu_exception( thread_t * this )
123	{
124	core_t * core = this->core;
125
126	// enable FPU (in core SR)
127	hal_fpu_enable();
128
129	// save FPU register values in current owner thread if required
130	if( core->fpu_owner != NULL )
131	{
132	if( core->fpu_owner != this )
133	{
134	// save the FPU registers to current owner thread context
135	hal_fpu_context_save( XPTR( local_cxy , core->fpu_owner ) );
136
137	// restore FPU registers from requesting thread context
138	hal_fpu_context_restore( this );
139
140	// attach the FPU to the requesting thread
141	core->fpu_owner = this;
142	}
143	}
144	else
145	{
146	// restore FPU registers from requesting thread context
147	hal_fpu_context_restore( this );
148
149	// attach the FPU to the requesting thread
150	core->fpu_owner = this;
151	}
152
153	return EXCP_NON_FATAL;
154
155	} // end hal_fpu_exception()
156
157	//////////////////////////////////////////////////////////////////////////////////////////
158	// This function is called when an MMU exception has been detected (IBE / DBE).
159	// It get the relevant exception arguments from the MMU.
160	// It signal a fatal error in case of illegal access. In case of page unmapped
161	// it checks that the faulty address belongs to a registered vseg. It update the local
162	// vseg list from the reference cluster if required, and signal a fatal user error
163	// in case of illegal virtual address. Finally, it updates the local page table from the
164	// reference cluster.
165	//////////////////////////////////////////////////////////////////////////////////////////
166	// @ this : pointer on faulty thread descriptor.
167	// @ excPC :
168	// @ is_ins : IBE if true / DBE if false.
169	// @ return EXCP_NON_FATAL / EXCP_USER_ERROR / EXCP_KERNEL_PANIC
170	//////////////////////////////////////////////////////////////////////////////////////////
171	error_t hal_mmu_exception( thread_t * this,
172	uint32_t excPC,
173	bool_t is_ins )
174	{
175	process_t * process;
176	error_t error;
177
178	uint32_t mmu_ins_excp_code;
179	uint32_t mmu_ins_bad_vaddr;
180	uint32_t mmu_dat_excp_code;
181	uint32_t mmu_dat_bad_vaddr;
182
183	uint32_t bad_vaddr;
184	uint32_t excp_code;
185
186	process = this->process;
187
188	// get relevant values from MMU
189	hal_get_mmu_excp( &mmu_ins_excp_code,
190	&mmu_ins_bad_vaddr,
191	&mmu_dat_excp_code,
192	&mmu_dat_bad_vaddr );
193
194	// get exception code and faulty vaddr, depending on IBE/DBE
195	if( is_ins )
196	{
197	excp_code = mmu_ins_excp_code;
198	bad_vaddr = mmu_ins_bad_vaddr;
199	}
200	else
201	{
202	excp_code = mmu_dat_excp_code;
203	bad_vaddr = mmu_dat_bad_vaddr;
204	}
205
206	#if DEBUG_HAL_EXCEPTIONS
207	uint32_t cycle = (uint32_t)hal_get_cycles();
208	if( DEBUG_HAL_EXCEPTIONS < cycle )
209	printk("\n[DBG] %s : thread[%x,%x] enter / is_ins %d / %s / vaddr %x / cycle %d\n",
210	__FUNCTION__, process->pid, this->trdid,
211	is_ins, hal_mmu_exception_str(excp_code), bad_vaddr, cycle);
212	#endif
213
214	// analyse exception code
215	switch( excp_code )
216	{
217	case MMU_WRITE_PT1_UNMAPPED: // non fatal
218	case MMU_WRITE_PT2_UNMAPPED:
219	case MMU_READ_PT1_UNMAPPED:
220	case MMU_READ_PT2_UNMAPPED:
221	{
222	// try to map the unmapped PTE
223	error = vmm_handle_page_fault( process,
224	bad_vaddr >> CONFIG_PPM_PAGE_SHIFT );
225
226	if( error == EXCP_NON_FATAL ) // page-fault successfully handled
227	{
228
229	#if DEBUG_HAL_EXCEPTIONS
230	cycle = (uint32_t)hal_get_cycles();
231	if( DEBUG_HAL_EXCEPTIONS < cycle )
232	printk("\n[DBG] %s : thread[%x,%x] exit / page-fault handled for vaddr = %x\n",
233	__FUNCTION__, process->pid, this->trdid, bad_vaddr );
234	#endif
235
236	return EXCP_NON_FATAL;
237	}
238	else if( error == EXCP_USER_ERROR ) // illegal vaddr
239	{
240	printk("\n[USER ERROR] in %s for thread %x in process %x\n"
241	" illegal vaddr = %x / is_ins %d / epc %x\n",
242	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
243
244	return EXCP_USER_ERROR;
245	}
246	else // error == EXCP_KERNEL_PANIC
247	{
248	printk("\n[KERNEL ERROR] in %s for thread %x in process %x\n"
249	" no memory to map vaddr = %x / is_ins %d / epc %x\n",
250	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
251
252	return EXCP_KERNEL_PANIC;
253	}
254	}
255	case MMU_WRITE_PRIVILEGE_VIOLATION: // illegal access user error
256	case MMU_READ_PRIVILEGE_VIOLATION:
257	{
258	printk("\n[USER ERROR] in %s : thread %x in process %x\n"
259	" illegal user access to vaddr = %x / is_ins %d / epc %x\n",
260	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
261
262	return EXCP_USER_ERROR;
263	}
264	case MMU_WRITE_ACCESS_VIOLATION: // user error, or Copy-on-Write
265	{
266	// access page table to get GPT_COW flag
267	bool_t cow = hal_gpt_pte_is_cow( &(process->vmm.gpt),
268	bad_vaddr >> CONFIG_PPM_PAGE_SHIFT );
269
270	if( cow ) // Copy-on-Write
271	{
272	// try to allocate and copy the page
273	error = vmm_handle_cow( process,
274	bad_vaddr >> CONFIG_PPM_PAGE_SHIFT );
275
276	if( error == EXCP_NON_FATAL ) // Copy on write successfull
277	{
278
279	#if DEBUG_HAL_EXCEPTIONS
280	cycle = (uint32_t)hal_get_cycles();
281	if( DEBUG_HAL_EXCEPTIONS < cycle )
282	printk("\n[DBG] %s : thread[%x,%x] exit / copy-on-write handled for vaddr = %x\n",
283	__FUNCTION__, process->pid, this->trdid, bad_vaddr );
284	#endif
285
286	return EXCP_NON_FATAL;
287	}
288	else if( error == EXCP_USER_ERROR ) // illegal user access
289	{
290	printk("\n[USER ERROR] in %s : thread %x in process %x\n"
291	" cannot cow vaddr = %x / is_ins %d / epc %x\n",
292	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
293
294	return EXCP_USER_ERROR;
295	}
296	else // error == EXCP_KERNEL_PANIC
297	{
298	printk("\n[KERNEL ERROR] in %s : thread %x in process %x\n"
299	" no memoty to cow vaddr = %x / is_ins %d / epc %x\n",
300	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
301
302	return EXCP_USER_ERROR;
303	}
304	}
305	else // non writable user error
306	{
307	printk("\n[USER ERROR] in %s : thread %x in process %x\n"
308	" non-writable vaddr = %x / is_ins %d / epc %x\n",
309	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
310
311	return EXCP_USER_ERROR;
312	}
313	}
314	case MMU_READ_EXEC_VIOLATION: // user error
315	{
316	printk("\n[USER_ERROR] in %s : thread %x in process %x\n"
317	" non-executable vaddr = %x / is_ins %d / epc %x\n",
318	__FUNCTION__, this->trdid, this->process->pid, bad_vaddr, is_ins, excPC );
319
320	return EXCP_USER_ERROR;
321	}
322	default: // this is a kernel error
323	{
324	printk("\n[KERNEL ERROR] in %s : thread %x in process %x\n"
325	" epc %x / badvaddr %x / is_ins %d\n",
326	__FUNCTION__, this->trdid, this->process->pid, excPC, bad_vaddr, is_ins );
327
328	return EXCP_KERNEL_PANIC;
329	}
330	}
331	} // end hal_mmu_exception()
332
333	//////////////////////////////////////////////////////////////////////////////////////////
334	// This static function prints on the kernel terminal the saved context (core registers)
335	// and the thread state of a faulty thread.
336	//////////////////////////////////////////////////////////////////////////////////////////
337	// @ this : pointer on faulty thread descriptor.
338	// @ uzone : pointer on register array.
339	// @ error : EXCP_USER_ERROR or EXCP_KERNEL_PANIC
340	//////////////////////////////////////////////////////////////////////////////////////////
341	static void hal_exception_dump( thread_t * this,
342	reg_t * uzone,
343	error_t error )
344	{
345	core_t * core = this->core;
346	process_t * process = this->process;
347
348	// get pointers on TXT0 chdev
349	xptr_t txt0_xp = chdev_dir.txt_tx[0];
350	cxy_t txt0_cxy = GET_CXY( txt0_xp );
351	chdev_t * txt0_ptr = GET_PTR( txt0_xp );
352
353	// get extended pointer on remote TXT0 chdev lock
354	xptr_t lock_xp = XPTR( txt0_cxy , &txt0_ptr->wait_lock );
355
356	// get TXT0 lock in busy waiting mode
357	remote_busylock_acquire( lock_xp );
358
359	if( error == EXCP_USER_ERROR )
360	{
361	nolock_printk("\n=== USER ERROR / trdid %x / pid %x / core[%x,%d] / cycle %d ===\n",
362	this->trdid, process->pid, local_cxy, core->lid , (uint32_t)hal_get_cycles() );
363	}
364	else
365	{
366	nolock_printk("\n=== KERNEL ERROR / trdid %x / pid %x / core[%x,%d] / cycle %d ===\n",
367	this->trdid, process->pid, local_cxy, core->lid , (uint32_t)hal_get_cycles() );
368	}
369
370	nolock_printk("busylocks = %d / blocked_vector = %X / flags = %X\n\n",
371	this->busylocks, this->blocked, this->flags );
372
373	nolock_printk("c0_cr %X c0_epc %X c0_sr %X c0_th %X\n",
374	uzone[UZ_CR], uzone[UZ_EPC], uzone[UZ_SR], uzone[UZ_TH] );
375
376	nolock_printk("c2_mode %X c2_ptpr %X\n",
377	uzone[UZ_MODE], uzone[UZ_PTPR] );
378
379	nolock_printk("at_01 %X v0_2 %X v1_3 %X a0_4 %X a1_5 %X\n",
380	uzone[UZ_AT], uzone[UZ_V0], uzone[UZ_V1], uzone[UZ_A0], uzone[UZ_A1] );
381
382	nolock_printk("a2_6 %X a3_7 %X t0_8 %X t1_9 %X t2_10 %X\n",
383	uzone[UZ_A2], uzone[UZ_A3], uzone[UZ_T0], uzone[UZ_T1], uzone[UZ_T2] );
384
385	nolock_printk("t3_11 %X t4_12 %X t5_13 %X t6_14 %X t7_15 %X\n",
386	uzone[UZ_T3], uzone[UZ_T4], uzone[UZ_T5], uzone[UZ_T6], uzone[UZ_T7] );
387
388	nolock_printk("s0_16 %X s1_17 %X s2_18 %X s3_19 %X s4_20 %X\n",
389	uzone[UZ_S0], uzone[UZ_S1], uzone[UZ_S2], uzone[UZ_S3], uzone[UZ_S4] );
390
391	nolock_printk("s5_21 %X s6_22 %X s7_23 %X s8_24 %X ra_25 %X\n",
392	uzone[UZ_S5], uzone[UZ_S6], uzone[UZ_S7], uzone[UZ_T8], uzone[UZ_T9] );
393
394	nolock_printk("gp_28 %X sp_29 %X S8_30 %X ra_31 %X\n",
395	uzone[UZ_GP], uzone[UZ_SP], uzone[UZ_S8], uzone[UZ_RA] );
396
397	// release the lock
398	remote_busylock_release( lock_xp );
399
400	} // end hal_exception_dump()
401
402	///////////////////////
403	void hal_do_exception( void )
404	{
405	uint32_t * uzone;
406	thread_t * this;
407	error_t error;
408	uint32_t excCode; // 4 bits XCODE from CP0_CR
409	uint32_t excPC; // fauty instruction address
410
411	// get pointer on faulty thread uzone
412	this = CURRENT_THREAD;
413	uzone = (uint32_t *)CURRENT_THREAD->uzone_current;
414
415	// get XCODE and EPC from UZONE
416	excCode = (uzone[UZ_CR] >> 2) & 0xF;
417	excPC = uzone[UZ_EPC];
418
419	#if DEBUG_HAL_EXCEPTIONS
420	uint32_t cycle = (uint32_t)hal_get_cycles();
421	if( DEBUG_HAL_EXCEPTIONS < cycle )
422	printk("\n[DBG] %s : thread %x in process %x enter / core[%x,%d] / epc %x / xcode %x / cycle %d\n",
423	__FUNCTION__, this->trdid, this->process->pid, local_cxy, this->core->lid, excPC, excCode, cycle );
424	#endif
425
426	switch(excCode)
427	{
428	case XCODE_DBE: // Data Bus Error : can be non fatal if page fault
429	{
430	error = hal_mmu_exception( this , excPC , false ); // data MMU exception
431	break;
432	}
433	case XCODE_IBE: // Instruction Bus Error : can be non fatal if page fault
434	{
435	error = hal_mmu_exception( this , excPC , true ); // ins MMU exception
436	break;
437	}
438	case XCODE_CPU: // Coprocessor unavailable : can be non fatal if FPU
439	{
440	if( ((uzone[UZ_CR] >> 28) & 0x3) == 1 ) // FPU
441	{
442	error = hal_fpu_exception( this );
443	}
444	else // undefined coprocessor
445	{
446	printk("\n[USER_ERROR] in %s for thread %x in process %x\n"
447	" undefined coprocessor / epc %x\n",
448	__FUNCTION__, this->trdid, this->process->pid, excPC );
449
450	error = EXCP_USER_ERROR;
451	}
452	break;
453	}
454	case XCODE_OVR: // Arithmetic Overflow : user fatal error
455	{
456	printk("\n[USER_ERROR] in %s for thread %x in process %x\n"
457	" arithmetic overflow / epc %x\n",
458	__FUNCTION__, this->trdid, this->process->pid, excPC );
459
460	error = EXCP_USER_ERROR;
461	break;
462	}
463	case XCODE_RI: // Reserved Instruction : user fatal error
464	{
465	printk("\n[USER_ERROR] in %s for thread %x in process %x\n"
466	" reserved instruction / epc %x\n",
467	__FUNCTION__, this->trdid, this->process->pid, excPC );
468
469	error = EXCP_USER_ERROR;
470	break;
471	}
472	case XCODE_ADEL: // user fatal error
473	{
474	printk("\n[USER_ERROR] in %s for thread %x in process %x\n"
475	" illegal data load address / epc %x\n",
476	__FUNCTION__, this->trdid, this->process->pid, excPC );
477
478	error = EXCP_USER_ERROR;
479	break;
480	}
481	case XCODE_ADES: // user fatal error
482	{
483	printk("\n[USER_ERROR] in %s for thread %x in process %x\n"
484	" illegal data store address / epc %x\n",
485	__FUNCTION__, this->trdid, this->process->pid, excPC );
486
487	error = EXCP_USER_ERROR;
488	break;
489	}
490	default:
491	{
492	error = EXCP_KERNEL_PANIC;
493	}
494	}
495
496	// analyse error code
497	if( error == EXCP_USER_ERROR ) // user error => kill user process
498	{
499	hal_exception_dump( this , uzone , error );
500
501	sys_exit( EXIT_FAILURE );
502	}
503	else if( error == EXCP_KERNEL_PANIC ) // kernel error => kernel panic
504	{
505	hal_exception_dump( this , uzone , error );
506
507	assert( false , "Exception raised kernel panic see information below.\n" );
508	}
509
510	#if DEBUG_HAL_EXCEPTIONS
511	cycle = (uint32_t)hal_get_cycles();
512	if( DEBUG_HAL_EXCEPTIONS < cycle )
513	printk("\n[DBG] %s : thread %x in process %x exit / core[%x,%d] / epc %x / xcode %x / cycle %d\n",
514	__FUNCTION__, this->trdid, this->process->pid, local_cxy, this->core->lid, excPC, excCode, cycle );
515	#endif
516
517	} // end hal_do_exception()
518
519

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