source: trunk/kernel/kern/do_exception.c@ 93

Last change on this file since 93 was 16, checked in by alain, 9 years ago

mprove the HAL for interrupt, exception, syscall handling.
File size: 10.4 KB
Line 
1/*
2 * do_exception.c - architecture independant exception handler implementation.
3 *
4 * Author Alain Greiner (2016)
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_types.h>
25#include <hal_irqmask.h>
26#include <kernel_config.h>
27#include <thread.h>
28#include <printk.h>
29#include <do_exception.h>
30
31//////////////////////////////////////////////////////////////////////////////////////////
32// This file containss the architecture independant exception handler.
33//
34// It is called by the architecture specific hal_do_exception() function.
35// The fatal errors are mostly handled by the architecture specific handler,
36// and this generic exception handler handles only two non fatal exceptions types:
37// - MMU page fault
38// - FPU unavailable
39//
40// As some MMU exceptions can be fatal, the returned error code can take three values:
41// - Non Fatal Exception
42// - Fatal User Error
43// - Kernel Panic Error
44//////////////////////////////////////////////////////////////////////////////////////////
45
46/////////////////////////////////////////////////////////////////////////////////////////
47// This remote_spinlock is a kernel global variable defined in all clusters.
48// It must be used by the architecture-specific exception handlers to display
49// error messages on the kernel terminal. Only the spinlock in the I/O cluster is used.
50/////////////////////////////////////////////////////////////////////////////////////////
51
52remote_spinlock_t exception_lock;
53
54
55//////////////////////////////////////////////////////////////////////////////////////////
56// This static function is called by the generic do_exception() handler when an MMU
57// exception has been detected.
58// It get the relevant exception arguments from the MMU.
59// It signal a fatal error in case of illegal access. In case of page fault,
60// it checks that the faulty address belongs to a registered vseg. It update the local
61// vseg list from the reference cluster if required, and signal a fatal user error
62// in case of illegal virtual address. Finally, it updates the local page table from the
63// reference cluster.
64//////////////////////////////////////////////////////////////////////////////////////////
65// @ this : pointer on faulty thread descriptor.
66// @ return EXCP_NON_FATAL / EXCP_USER_ERROR / EXCP_KERNEL_PANIC
67//////////////////////////////////////////////////////////////////////////////////////////
68static error_t mmu_exception( thread_t * this )
69{
70 vseg_t * vseg; // vseg containing the bad_vaddr
71 process_t * process; // local process descriptor
72 vmm_t * vmm; // VMM for calling thread
73 error_t error; // return value
74
75 reg_t mmu_ins_excp_code;
76 reg_t mmu_ins_bad_vaddr;
77 reg_t mmu_dat_excp_code;
78 reg_t mmu_dat_bad_vaddr;
79
80 intptr_t bad_vaddr;
81 uint32_t excp_code;
82
83 process = this->process;
84 vmm = &process->vmm;
85
86 vmm_dmsg("\n[INFO] %s : enters for thread %x / process %x"
87 " / bad_vaddr = %x / excep_code = %x\n",
88 __FUNCTION__, this->trdid , process->pid , bad_vaddr , excep_code );
89
90 // get relevant values from MMU
91 hal_get_mmu_excp( &mmu_ins_excp_code,
92 &mmu_ins_bad_vaddr,
93 &mmu_dat_excp_code,
94 &mmu_dat_bad_vaddr );
95
96 // get exception code and faulty vaddr
97 if( mmu_ins_excp_code )
98 {
99 excp_code = mmu_ins_excp_code;
100 bad_vaddr = mmu_ins_bad_vaddr;
101 }
102 else if( mmu_dat_excp_code )
103 {
104 excp_code = mmu_dat_excp_code;
105 bad_vaddr = mmu_dat_bad_vaddr;
106 }
107 else
108 {
109 return EXCP_NON_FATAL;
110 }
111
112
113 // a kernel thread should not rise an MMU exception
114 if( this->type != THREAD_USER )
115 {
116 printk("\n[PANIC] in %s : thread %x is a kernel thread / vaddr = %x\n",
117 __FUNCTION__ , this->trdid , bad_vaddr );
118 return EXCP_KERNEL_PANIC;
119 }
120
121 // enable IRQs
122 hal_enable_irq( NULL );
123
124 // vaddr must be contained in a registered vseg
125 vseg = vmm_get_vseg( process , bad_vaddr );
126
127 if( vseg == NULL ) // vseg not found in local cluster
128 {
129 // get extended pointer on reference process
130 xptr_t ref_xp = process->ref_xp;
131
132 // get cluster and local pointer on reference process
133 cxy_t ref_cxy = GET_CXY( ref_xp );
134 process_t * ref_ptr = (process_t *)GET_PTR( ref_xp );
135
136 if( local_cxy != ref_cxy ) // reference process is remote
137 {
138 // get extended pointer on reference vseg
139 xptr_t vseg_xp;
140 rpc_vmm_get_ref_vseg_client( ref_cxy , ref_ptr , bad_vaddr , &vseg_xp );
141
142
143 if( vseg == NULL ) // vseg not found => illegal user vaddr
144 {
145 printk("\n[ERROR] in %s for thread %x : illegal vaddr = %x\n",
146 __FUNCTION__ , this->trdid , bad_vaddr );
147
148 hal_disable_irq( NULL );
149 return EXCP_USER_ERROR;
150 }
151 else // vseg found => make a local copy
152 {
153 // allocate a vseg in local cluster
154 vseg = vseg_alloc();
155
156 if( vseg == NULL )
157 {
158 printk("\n[PANIC] in %s : no memory for vseg / thread = %x\n",
159 __FUNCTION__ , this->trdid );
160 hal_disable_irq( NULL );
161 return EXCP_KERNEL_PANIC;
162 }
163
164 // initialise local vseg from reference
165 vseg_init_from_ref( vseg , ref_xp );
166
167 // register local vseg in local VMM
168 error = vseg_attach( &process->vmm , vseg );
169 }
170 }
171 else // reference is local => illegal user vaddr
172 {
173 printk("\n[ERROR] in %s for thread %x : illegal vaddr = %x\n",
174 __FUNCTION__ , this->trdid , bad_vaddr );
175
176 hal_disable_irq( NULL );
177 return EXCP_USER_ERROR;
178 }
179 }
180
181 vmm_dmsg("\n[INFO] %s : found vseg for thread %x / vseg_base = %x / vseg_size = %x\n",
182 __FUNCTION__ , this->trdid , vseg->begin , vseg->size );
183
184 // analyse exception code
185 if( excp_code & MMU_EXCP_PAGE_UNMAPPED )
186 {
187 // try to map the unmapped PTE
188 error = vmm_handle_page_fault( process,
189 vseg,
190 bad_vaddr >> CONFIG_PPM_PAGE_SHIFT ); // vpn
191
192 if( error )
193 {
194 printk("\n[PANIC] in %s for thread %x : cannot map legal vaddr = %x\n",
195 __FUNCTION__ , this->trdid , bad_vaddr );
196
197 hal_disable_irq( NULL );
198 return EXCP_KERNEL_PANIC;
199 }
200 else
201 {
202 vmm_dmsg("\n[INFO] %s : page fault handled for vaddr = %x in thread %x\n",
203 __FUNCTION__ , bad_vaddr , this->trdid );
204
205 // page fault successfully handled
206 hal_disable_irq( NULL );
207
208 // TODO Pourquoi ce yield ? [AG]
209 // sched_yield();
210
211 return EXCP_NON_FATAL;
212 }
213 }
214 else if( excp_code & MMU_EXCP_USER_PRIVILEGE )
215 {
216 printk("\n[ERROR] in %s for thread %x : user access to kernel vseg at vaddr = %x\n",
217 __FUNCTION__ , this->trdid , bad_vaddr );
218
219 hal_disable_irq( NULL );
220 return EXCP_USER_ERROR;
221 }
222 else if( excp_code & MMU_EXCP_USER_EXEC )
223 {
224 printk("\n[ERROR] in %s for thread %x : access to non-exec vseg at vaddr = %x\n",
225 __FUNCTION__ , this->trdid , bad_vaddr );
226
227 hal_disable_irq( NULL );
228 return EXCP_USER_ERROR;
229 }
230 else if( excp_code & MMU_EXCP_USER_WRITE )
231 {
232 printk("\n[ERROR] in %s for thread %x : write to non-writable vseg at vaddr = %x\n",
233 __FUNCTION__ , this->trdid , bad_vaddr );
234
235 hal_disable_irq( NULL );
236 return EXCP_USER_ERROR;
237 }
238
239 else // this is a kernel error => panic
240 {
241 printk("\n[PANIC] in %s for thread %x : kernel exception = %x / vaddr = %x\n",
242 __FUNCTION__ , this->trdid , excp_code , bad_vaddr );
243
244 hal_disable_irq( NULL );
245 return EXCP_KERNEL_PANIC;
246 }
247
248} // end mmu_exception_handler()
249
250//////////////////////////////////////////////////////////////////////////////////////////
251// This static function is called by the generic do_exception() handler when a
252// FPU Coprocessor Unavailable exception has been detected by the calling thread.
253// It enables the FPU, It saves the current FPU context in the current owner thread
254// descriptor if required, and restore the FPU context from the calling thread descriptor.
255//////////////////////////////////////////////////////////////////////////////////////////
256// @ thread : pointer on faulty thread descriptor.
257// @ return always EXCP_NON_FATAL
258//////////////////////////////////////////////////////////////////////////////////////////
259static error_t fpu_exception( thread_t * this )
260{
261 core_t * core = this->core;
262
263 // enable FPU
264 hal_fpu_enable();
265
266 // save FPU context in current owner thread if required
267 if( core->fpu_owner != NULL )
268 {
269 if( core->fpu_owner != this )
270 {
271 hal_fpu_context_save ( core->fpu_owner->fpu_context );
272 }
273 }
274
275 // attach the FPU to the requesting thread
276 hal_fpu_context_restore( this->fpu_context );
277 core->fpu_owner = this;
278
279 return EXCP_NON_FATAL;
280}
281
282
283//////////////////////////////////////
284error_t do_exception( thread_t * this,
285 bool_t is_mmu )
286{
287 error_t error;
288
289 // update user time
290 thread_user_time_update( this );
291
292 // try to handle non fatal exception
293 if( is_mmu ) error = mmu_exception( this );
294 else error = fpu_exception( this );
295
296 // handle pending signals for interrupted thread
297 thread_signals_handle( this );
298
299 // update kernel time
300 thread_kernel_time_update( this );
301
302 return error;
303}
Note: See TracBrowser for help on using the repository browser.