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source: trunk/hal/tsar_mips32/core/hal_exception.c @ 457

Last change on this file since 457 was 457, checked in by alain, 6 years ago
This version modifies the exec syscall and fixes a large number of small bugs. The version number has been updated (0.1)
File size: 17.9 KB

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

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