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001 /* Copyright (C) 2005 David Decotigny 001 /* Copyright (C) 2005 David Decotigny 002 002 003 This program is free software; you can redi 003 This program is free software; you can redistribute it and/or 004 modify it under the terms of the GNU Genera 004 modify it under the terms of the GNU General Public License 005 as published by the Free Software Foundatio 005 as published by the Free Software Foundation; either version 2 006 of the License, or (at your option) any lat 006 of the License, or (at your option) any later version. 007 007 008 This program is distributed in the hope tha 008 This program is distributed in the hope that it will be useful, 009 but WITHOUT ANY WARRANTY; without even the 009 but WITHOUT ANY WARRANTY; without even the implied warranty of 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 011 GNU General Public License for more details 011 GNU General Public License for more details. 012 012 013 You should have received a copy of the GNU 013 You should have received a copy of the GNU General Public License 014 along with this program; if not, write to t 014 along with this program; if not, write to the Free Software 015 Foundation, Inc., 59 Temple Place - Suite 3 015 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 016 USA. 016 USA. 017 */ 017 */ 018 018 019 #include <sos/assert.h> 019 #include <sos/assert.h> 020 #include <sos/kmalloc.h> 020 #include <sos/kmalloc.h> 021 #include <sos/physmem.h> 021 #include <sos/physmem.h> 022 #include <hwcore/paging.h> 022 #include <hwcore/paging.h> 023 #include <sos/kmem_slab.h> 023 #include <sos/kmem_slab.h> 024 #include <sos/list.h> 024 #include <sos/list.h> 025 #include <hwcore/paging.h> 025 #include <hwcore/paging.h> 026 #include <sos/uaccess.h> 026 #include <sos/uaccess.h> 027 #include <sos/chardev.h> 027 #include <sos/chardev.h> 028 #include <drivers/devices.h> 028 #include <drivers/devices.h> 029 029 030 #include "zero.h" 030 #include "zero.h" 031 031 032 032 033 /** 033 /** 034 * A mapped page for a shared mapping of /dev/ 034 * A mapped page for a shared mapping of /dev/zero 035 */ 035 */ 036 struct zero_mapped_page 036 struct zero_mapped_page 037 { 037 { 038 sos_uoffset_t page_id; 038 sos_uoffset_t page_id; 039 sos_paddr_t ppage_paddr; 039 sos_paddr_t ppage_paddr; 040 040 041 struct zero_mapped_page *prev, *next; 041 struct zero_mapped_page *prev, *next; 042 }; 042 }; 043 /** The Slab cache of shared mapped pages */ 043 /** The Slab cache of shared mapped pages */ 044 struct sos_kslab_cache * cache_of_zero_mapped_ 044 struct sos_kslab_cache * cache_of_zero_mapped_pages; 045 045 046 046 047 /** 047 /** 048 * A mapped /dev/zero resource 048 * A mapped /dev/zero resource 049 */ 049 */ 050 struct zero_mapped_resource 050 struct zero_mapped_resource 051 { 051 { 052 int ref_cnt; 052 int ref_cnt; 053 053 054 /** 054 /** 055 * For shared mappings: the list of shared p 055 * For shared mappings: the list of shared pages mapped inside one 056 * or multiple VRs 056 * or multiple VRs 057 */ 057 */ 058 struct zero_mapped_page *list_mapped_pages; 058 struct zero_mapped_page *list_mapped_pages; 059 059 060 struct sos_umem_vmm_mapped_resource mr; 060 struct sos_umem_vmm_mapped_resource mr; 061 }; 061 }; 062 062 063 063 064 /** Forward declaration: the FS operation for 064 /** Forward declaration: the FS operation for the /dev/zero character 065 device */ 065 device */ 066 static struct sos_chardev_ops dev_zero_fs_ops; 066 static struct sos_chardev_ops dev_zero_fs_ops; 067 067 068 068 069 /** Helper function to insert the given physic 069 /** Helper function to insert the given physical page in the list of 070 physical pages used for shared anonymous m 070 physical pages used for shared anonymous mappings */ 071 static sos_ret_t insert_anonymous_physpage(str 071 static sos_ret_t insert_anonymous_physpage(struct zero_mapped_resource *mr, 072 sos 072 sos_paddr_t ppage_paddr, 073 sos 073 sos_uoffset_t page_id); 074 074 075 075 076 /** Helper function to insert the given physic 076 /** Helper function to insert the given physical page in the list of 077 physical pages used for shared anonymous m 077 physical pages used for shared anonymous mappings */ 078 static sos_paddr_t lookup_anonymous_physpage(s 078 static sos_paddr_t lookup_anonymous_physpage(struct zero_mapped_resource *mr, 079 s 079 sos_uoffset_t page_id); 080 080 081 081 082 sos_ret_t sos_dev_zero_subsystem_setup() 082 sos_ret_t sos_dev_zero_subsystem_setup() 083 { 083 { 084 sos_ret_t retval; 084 sos_ret_t retval; 085 085 086 cache_of_zero_mapped_pages = 086 cache_of_zero_mapped_pages = 087 sos_kmem_cache_create("shared anonymous ma 087 sos_kmem_cache_create("shared anonymous mappings", 088 sizeof(struct zero_m 088 sizeof(struct zero_mapped_page), 089 1, 0, 089 1, 0, 090 SOS_KSLAB_CREATE_MAP 090 SOS_KSLAB_CREATE_MAP | SOS_KSLAB_CREATE_ZERO); 091 if (! cache_of_zero_mapped_pages) 091 if (! cache_of_zero_mapped_pages) 092 return -SOS_ENOMEM; 092 return -SOS_ENOMEM; 093 093 094 retval = sos_chardev_register_class(SOS_CHAR 094 retval = sos_chardev_register_class(SOS_CHARDEV_ZERO_MAJOR, 095 & dev_ze 095 & dev_zero_fs_ops, 096 NULL); 096 NULL); 097 if (SOS_OK != retval) 097 if (SOS_OK != retval) 098 { 098 { 099 sos_kmem_cache_destroy(cache_of_zero_map 099 sos_kmem_cache_destroy(cache_of_zero_mapped_pages); 100 return retval; 100 return retval; 101 } 101 } 102 102 103 return SOS_OK; 103 return SOS_OK; 104 } 104 } 105 105 106 106 107 /** Called after the virtual region has been i 107 /** Called after the virtual region has been inserted inside its 108 address space */ 108 address space */ 109 static void zero_ref(struct sos_umem_vmm_vr * 109 static void zero_ref(struct sos_umem_vmm_vr * vr) 110 { 110 { 111 /* Retrieve the 'zero' structure associated 111 /* Retrieve the 'zero' structure associated with the mapped resource */ 112 struct zero_mapped_resource * zero_resource; 112 struct zero_mapped_resource * zero_resource; 113 zero_resource 113 zero_resource 114 = (struct zero_mapped_resource*) 114 = (struct zero_mapped_resource*) 115 sos_umem_vmm_get_mapped_resource_of_vr(vr) 115 sos_umem_vmm_get_mapped_resource_of_vr(vr)->custom_data; 116 116 117 /* Increment ref counter */ 117 /* Increment ref counter */ 118 zero_resource->ref_cnt ++; 118 zero_resource->ref_cnt ++; 119 } 119 } 120 120 121 121 122 /** Called when the virtual region is removed 122 /** Called when the virtual region is removed from its address 123 space */ 123 space */ 124 static void zero_unref(struct sos_umem_vmm_vr 124 static void zero_unref(struct sos_umem_vmm_vr * vr) 125 { 125 { 126 /* Retrieve the 'zero' structure associated 126 /* Retrieve the 'zero' structure associated with the mapped resource */ 127 struct zero_mapped_resource * zero_resource; 127 struct zero_mapped_resource * zero_resource; 128 zero_resource 128 zero_resource 129 = (struct zero_mapped_resource*) 129 = (struct zero_mapped_resource*) 130 sos_umem_vmm_get_mapped_resource_of_vr(vr) 130 sos_umem_vmm_get_mapped_resource_of_vr(vr)->custom_data; 131 131 132 /* Decrement ref coutner */ 132 /* Decrement ref coutner */ 133 SOS_ASSERT_FATAL(zero_resource->ref_cnt > 0) 133 SOS_ASSERT_FATAL(zero_resource->ref_cnt > 0); 134 zero_resource->ref_cnt --; 134 zero_resource->ref_cnt --; 135 135 136 /* Free the resource if it becomes unused */ 136 /* Free the resource if it becomes unused */ 137 if (zero_resource->ref_cnt == 0) 137 if (zero_resource->ref_cnt == 0) 138 { 138 { 139 /* Delete the list of anonymous shared m 139 /* Delete the list of anonymous shared mappings */ 140 struct zero_mapped_page *zmp; 140 struct zero_mapped_page *zmp; 141 list_collapse(zero_resource->list_mapped 141 list_collapse(zero_resource->list_mapped_pages, zmp) 142 { 142 { 143 /* Unreference the underlying physic 143 /* Unreference the underlying physical page */ 144 sos_physmem_unref_physpage(zmp->ppag 144 sos_physmem_unref_physpage(zmp->ppage_paddr); 145 sos_kfree((sos_vaddr_t)zmp); 145 sos_kfree((sos_vaddr_t)zmp); 146 } 146 } 147 147 148 sos_kfree((sos_vaddr_t)zero_resource); 148 sos_kfree((sos_vaddr_t)zero_resource); 149 } 149 } 150 } 150 } 151 151 152 152 153 /** MOST IMPORTANT callback ! Called when a th 153 /** MOST IMPORTANT callback ! Called when a thread page faults on the 154 resource's mapping */ 154 resource's mapping */ 155 static sos_ret_t zero_page_in(struct sos_umem_ 155 static sos_ret_t zero_page_in(struct sos_umem_vmm_vr * vr, 156 sos_uaddr_t uadd 156 sos_uaddr_t uaddr, 157 sos_bool_t write 157 sos_bool_t write_access) 158 { 158 { 159 sos_ret_t retval = SOS_OK; 159 sos_ret_t retval = SOS_OK; 160 sos_paddr_t ppage_paddr; 160 sos_paddr_t ppage_paddr; 161 sos_uoffset_t required_page_id; 161 sos_uoffset_t required_page_id; 162 struct zero_mapped_resource * zero_resource; 162 struct zero_mapped_resource * zero_resource; 163 sos_ui32_t vr_prot, vr_flags; 163 sos_ui32_t vr_prot, vr_flags; 164 164 165 /* Retrieve the 'zero' structure associated 165 /* Retrieve the 'zero' structure associated with the mapped resource */ 166 zero_resource 166 zero_resource 167 = (struct zero_mapped_resource*) 167 = (struct zero_mapped_resource*) 168 sos_umem_vmm_get_mapped_resource_of_vr(vr) 168 sos_umem_vmm_get_mapped_resource_of_vr(vr)->custom_data; 169 169 170 /* Retrieve access rights/flags of the VR */ 170 /* Retrieve access rights/flags of the VR */ 171 vr_prot = sos_umem_vmm_get_prot_of_vr(vr); 171 vr_prot = sos_umem_vmm_get_prot_of_vr(vr); 172 vr_flags = sos_umem_vmm_get_flags_of_vr(vr); 172 vr_flags = sos_umem_vmm_get_flags_of_vr(vr); 173 173 174 /* Identifies the page in the mapping that's 174 /* Identifies the page in the mapping that's being paged-in */ 175 required_page_id = SOS_PAGE_ALIGN_INF(uaddr) 175 required_page_id = SOS_PAGE_ALIGN_INF(uaddr) 176 - sos_umem_vmm_get_start_of_vr(vr) 176 - sos_umem_vmm_get_start_of_vr(vr) 177 + sos_umem_vmm_get_offset_in_resource(vr); 177 + sos_umem_vmm_get_offset_in_resource(vr); 178 178 179 /* For shared mappings, check if there is a 179 /* For shared mappings, check if there is a page already mapping the 180 required address */ 180 required address */ 181 if (vr_flags & SOS_VR_MAP_SHARED) 181 if (vr_flags & SOS_VR_MAP_SHARED) 182 { 182 { 183 ppage_paddr = lookup_anonymous_physpage( 183 ppage_paddr = lookup_anonymous_physpage(zero_resource, required_page_id); 184 if (NULL != (void*)ppage_paddr) 184 if (NULL != (void*)ppage_paddr) 185 { 185 { 186 retval = sos_paging_map(ppage_paddr, 186 retval = sos_paging_map(ppage_paddr, 187 SOS_PAGE_ALI 187 SOS_PAGE_ALIGN_INF(uaddr), 188 TRUE, 188 TRUE, 189 vr_prot); 189 vr_prot); 190 190 191 return retval; 191 return retval; 192 } 192 } 193 } 193 } 194 194 195 /* For write accesses, directly maps a new p 195 /* For write accesses, directly maps a new page. For read accesses, 196 simply map in the zero_page (and wait for 196 simply map in the zero_page (and wait for COW to handle the next 197 write accesses) */ 197 write accesses) */ 198 if (write_access) 198 if (write_access) 199 { 199 { 200 /* Allocate a new page for the virtual a 200 /* Allocate a new page for the virtual address */ 201 ppage_paddr = sos_physmem_ref_physpage_n 201 ppage_paddr = sos_physmem_ref_physpage_new(FALSE); 202 if (! ppage_paddr) 202 if (! ppage_paddr) 203 return -SOS_ENOMEM; 203 return -SOS_ENOMEM; 204 204 205 retval = sos_paging_map(ppage_paddr, 205 retval = sos_paging_map(ppage_paddr, 206 SOS_PAGE_ALIGN_I 206 SOS_PAGE_ALIGN_INF(uaddr), 207 TRUE, 207 TRUE, 208 vr_prot); 208 vr_prot); 209 if (SOS_OK != retval) 209 if (SOS_OK != retval) 210 { 210 { 211 sos_physmem_unref_physpage(ppage_pad 211 sos_physmem_unref_physpage(ppage_paddr); 212 return retval; 212 return retval; 213 } 213 } 214 214 215 memset((void*)SOS_PAGE_ALIGN_INF(uaddr), 215 memset((void*)SOS_PAGE_ALIGN_INF(uaddr), 0x0, SOS_PAGE_SIZE); 216 216 217 /* For shared mappings, add the page in 217 /* For shared mappings, add the page in the list of shared 218 mapped pages */ 218 mapped pages */ 219 if (vr_flags & SOS_VR_MAP_SHARED) 219 if (vr_flags & SOS_VR_MAP_SHARED) 220 insert_anonymous_physpage(zero_resourc 220 insert_anonymous_physpage(zero_resource, ppage_paddr, 221 required_pag 221 required_page_id); 222 222 223 sos_physmem_unref_physpage(ppage_paddr); 223 sos_physmem_unref_physpage(ppage_paddr); 224 } 224 } 225 else 225 else 226 { 226 { 227 /* Map-in the zero page in READ ONLY wha 227 /* Map-in the zero page in READ ONLY whatever the access_rights 228 or the type (shared/private) of the V 228 or the type (shared/private) of the VR to activate COW */ 229 retval = sos_paging_map(sos_zero_physpag 229 retval = sos_paging_map(sos_zero_physpage, 230 SOS_PAGE_ALIGN_I 230 SOS_PAGE_ALIGN_INF(uaddr), 231 TRUE, 231 TRUE, 232 SOS_VM_MAP_PROT_ 232 SOS_VM_MAP_PROT_READ); 233 } 233 } 234 234 235 return retval; 235 return retval; 236 } 236 } 237 237 238 238 239 /** The callbacks for a mapped /dev/zero resou 239 /** The callbacks for a mapped /dev/zero resource */ 240 static struct sos_umem_vmm_vr_ops zero_ops = ( 240 static struct sos_umem_vmm_vr_ops zero_ops = (struct sos_umem_vmm_vr_ops) 241 { 241 { 242 .ref = zero_ref, 242 .ref = zero_ref, 243 .unref = zero_unref, 243 .unref = zero_unref, 244 .page_in = zero_page_in, 244 .page_in = zero_page_in, 245 .unmap = NULL 245 .unmap = NULL 246 }; 246 }; 247 247 248 248 249 /** The callback that gets called when the res 249 /** The callback that gets called when the resource gets mapped */ 250 static sos_ret_t zero_mmap(struct sos_umem_vmm 250 static sos_ret_t zero_mmap(struct sos_umem_vmm_vr *vr) 251 { 251 { 252 return sos_umem_vmm_set_ops_of_vr(vr, &zero_ 252 return sos_umem_vmm_set_ops_of_vr(vr, &zero_ops); 253 } 253 } 254 254 255 255 256 /** The function responsible for mapping the / 256 /** The function responsible for mapping the /dev/zero resource in 257 user space */ 257 user space */ 258 sos_ret_t sos_dev_zero_map(struct sos_umem_vmm 258 sos_ret_t sos_dev_zero_map(struct sos_umem_vmm_as * dest_as, 259 sos_uaddr_t *uaddr, 259 sos_uaddr_t *uaddr, 260 sos_size_t size, 260 sos_size_t size, 261 sos_ui32_t access_r 261 sos_ui32_t access_rights, 262 sos_ui32_t flags) 262 sos_ui32_t flags) 263 { 263 { 264 sos_ret_t retval; 264 sos_ret_t retval; 265 struct zero_mapped_resource * zero_resource; 265 struct zero_mapped_resource * zero_resource; 266 266 267 zero_resource 267 zero_resource 268 = (struct zero_mapped_resource*) sos_kmall 268 = (struct zero_mapped_resource*) sos_kmalloc(sizeof(*zero_resource), 0); 269 if (! zero_resource) 269 if (! zero_resource) 270 return -SOS_ENOMEM; 270 return -SOS_ENOMEM; 271 271 272 memset(zero_resource, 0x0, sizeof(*zero_reso 272 memset(zero_resource, 0x0, sizeof(*zero_resource)); 273 zero_resource->mr.allowed_access_rights 273 zero_resource->mr.allowed_access_rights 274 = SOS_VM_MAP_PROT_READ 274 = SOS_VM_MAP_PROT_READ 275 | SOS_VM_MAP_PROT_WRITE 275 | SOS_VM_MAP_PROT_WRITE 276 | SOS_VM_MAP_PROT_EXEC; 276 | SOS_VM_MAP_PROT_EXEC; 277 zero_resource->mr.flags |= SOS_MAPPE 277 zero_resource->mr.flags |= SOS_MAPPED_RESOURCE_ANONYMOUS; 278 zero_resource->mr.custom_data = zero_reso 278 zero_resource->mr.custom_data = zero_resource; 279 zero_resource->mr.mmap = zero_mmap 279 zero_resource->mr.mmap = zero_mmap; 280 280 281 retval = sos_umem_vmm_map(dest_as, uaddr, si 281 retval = sos_umem_vmm_map(dest_as, uaddr, size, 282 access_rights, fla 282 access_rights, flags, 283 &zero_resource->mr 283 &zero_resource->mr, 0); 284 if (SOS_OK != retval) 284 if (SOS_OK != retval) 285 { 285 { 286 sos_kfree((sos_vaddr_t)zero_resource); 286 sos_kfree((sos_vaddr_t)zero_resource); 287 return retval; 287 return retval; 288 } 288 } 289 289 290 return SOS_OK; 290 return SOS_OK; 291 } 291 } 292 292 293 293 294 static sos_ret_t insert_anonymous_physpage(str 294 static sos_ret_t insert_anonymous_physpage(struct zero_mapped_resource *mr, 295 sos 295 sos_paddr_t ppage_paddr, 296 sos 296 sos_uoffset_t page_id) 297 { 297 { 298 struct zero_mapped_page * zmp 298 struct zero_mapped_page * zmp 299 = (struct zero_mapped_page*)sos_kmem_cache 299 = (struct zero_mapped_page*)sos_kmem_cache_alloc(cache_of_zero_mapped_pages, 300 300 0); 301 if (! zmp) 301 if (! zmp) 302 return -SOS_ENOMEM; 302 return -SOS_ENOMEM; 303 303 304 zmp->page_id = page_id; 304 zmp->page_id = page_id; 305 zmp->ppage_paddr = ppage_paddr; 305 zmp->ppage_paddr = ppage_paddr; 306 306 307 list_add_head(mr->list_mapped_pages, zmp); 307 list_add_head(mr->list_mapped_pages, zmp); 308 sos_physmem_ref_physpage_at(ppage_paddr); 308 sos_physmem_ref_physpage_at(ppage_paddr); 309 return SOS_OK; 309 return SOS_OK; 310 } 310 } 311 311 312 312 313 static sos_paddr_t lookup_anonymous_physpage(s 313 static sos_paddr_t lookup_anonymous_physpage(struct zero_mapped_resource *mr, 314 s !! 314 sos_uoffset_t page_id) 315 { 315 { 316 struct zero_mapped_page * zmp; 316 struct zero_mapped_page * zmp; 317 int nb_elts; 317 int nb_elts; 318 318 319 list_foreach_forward(mr->list_mapped_pages, 319 list_foreach_forward(mr->list_mapped_pages, zmp, nb_elts) 320 { 320 { 321 if (zmp->page_id == page_id) 321 if (zmp->page_id == page_id) 322 return zmp->ppage_paddr; 322 return zmp->ppage_paddr; 323 } 323 } 324 324 325 return (sos_paddr_t)NULL; 325 return (sos_paddr_t)NULL; 326 } 326 } 327 327 328 /* 328 /* 329 * /dev/zero character device FS operations 329 * /dev/zero character device FS operations 330 */ 330 */ 331 331 332 static sos_ret_t dev_zero_fs_open(struct sos_f 332 static sos_ret_t dev_zero_fs_open(struct sos_fs_node * fsnode, 333 struct sos_f 333 struct sos_fs_opened_file * of, 334 void * chard 334 void * chardev_class_custom_data) 335 { 335 { 336 /* Make sure the device instance is known to 336 /* Make sure the device instance is known to the driver */ 337 if ( (SOS_CHARDEV_NULL_MINOR != fsnode->dev_ 337 if ( (SOS_CHARDEV_NULL_MINOR != fsnode->dev_id.device_instance) 338 && (SOS_CHARDEV_ZERO_MINOR != fsnode->d 338 && (SOS_CHARDEV_ZERO_MINOR != fsnode->dev_id.device_instance) ) 339 return -SOS_ENODEV; 339 return -SOS_ENODEV; 340 340 341 return SOS_OK; 341 return SOS_OK; 342 } 342 } 343 343 344 344 345 static sos_ret_t dev_zero_fs_seek(struct sos_f 345 static sos_ret_t dev_zero_fs_seek(struct sos_fs_opened_file *this, 346 sos_lsoffset 346 sos_lsoffset_t offset, 347 sos_seek_whe 347 sos_seek_whence_t whence, 348 /* out */ so 348 /* out */ sos_lsoffset_t * result_position) 349 { 349 { 350 /* Artificiallly update the position in the 350 /* Artificiallly update the position in the "file" */ 351 sos_lsoffset_t ref_offs; 351 sos_lsoffset_t ref_offs; 352 352 353 *result_position = this->position; 353 *result_position = this->position; 354 switch (whence) 354 switch (whence) 355 { 355 { 356 case SOS_SEEK_SET: 356 case SOS_SEEK_SET: 357 ref_offs = 0; 357 ref_offs = 0; 358 break; 358 break; 359 359 360 case SOS_SEEK_CUR: 360 case SOS_SEEK_CUR: 361 ref_offs = this->position; 361 ref_offs = this->position; 362 break; 362 break; 363 363 364 case SOS_SEEK_END: 364 case SOS_SEEK_END: 365 return -SOS_ENOSUP; 365 return -SOS_ENOSUP; 366 break; 366 break; 367 367 368 default: 368 default: 369 return -SOS_EINVAL; 369 return -SOS_EINVAL; 370 } 370 } 371 371 372 if (offset < -ref_offs) 372 if (offset < -ref_offs) 373 return -SOS_EINVAL; 373 return -SOS_EINVAL; 374 374 375 this->position = ref_offs + offset; 375 this->position = ref_offs + offset; 376 *result_position = this->position; 376 *result_position = this->position; 377 return SOS_OK; 377 return SOS_OK; 378 } 378 } 379 379 380 380 381 static sos_ret_t dev_zero_fs_read(struct sos_f 381 static sos_ret_t dev_zero_fs_read(struct sos_fs_opened_file *this, 382 sos_uaddr_t 382 sos_uaddr_t dest_buf, 383 sos_size_t * 383 sos_size_t * /* in/out */len) 384 { 384 { 385 struct sos_fs_node * fsnode = sos_fs_nscache 385 struct sos_fs_node * fsnode = sos_fs_nscache_get_fs_node(this->direntry); 386 sos_size_t offs, rdlen; 386 sos_size_t offs, rdlen; 387 387 388 /* Reading /dev/null returns immediately */ 388 /* Reading /dev/null returns immediately */ 389 if (SOS_CHARDEV_NULL_MINOR == fsnode->dev_id 389 if (SOS_CHARDEV_NULL_MINOR == fsnode->dev_id.device_instance) 390 { 390 { 391 *len = 0; 391 *len = 0; 392 return SOS_OK; 392 return SOS_OK; 393 } 393 } 394 394 395 /* ZERO the destination buffer using the zer 395 /* ZERO the destination buffer using the zero page (by page_size 396 increments) */ 396 increments) */ 397 for (rdlen = offs = 0 ; offs < *len ; offs + 397 for (rdlen = offs = 0 ; offs < *len ; offs += SOS_PAGE_SIZE) 398 { 398 { 399 sos_ret_t retval; !! 399 sos_size_t retval, memcpy_len = SOS_PAGE_SIZE; 400 sos_size_t memcpy_len = SOS_PAGE_SIZE; << 401 if (offs + memcpy_len > *len) 400 if (offs + memcpy_len > *len) 402 memcpy_len = *len - offs; 401 memcpy_len = *len - offs; 403 402 404 retval = sos_memcpy_to_user(dest_buf + o 403 retval = sos_memcpy_to_user(dest_buf + offs, sos_zero_kernelpage, 405 memcpy_len); 404 memcpy_len); 406 if (retval < 0) 405 if (retval < 0) 407 break; 406 break; 408 407 409 rdlen += retval; 408 rdlen += retval; 410 if (retval != (sos_ret_t)memcpy_len) !! 409 if (retval != memcpy_len) 411 break; 410 break; 412 } 411 } 413 412 414 /* Artificiallly update the position in the 413 /* Artificiallly update the position in the "file" */ 415 *len = rdlen; 414 *len = rdlen; 416 this->position += rdlen; 415 this->position += rdlen; 417 return SOS_OK; 416 return SOS_OK; 418 } 417 } 419 418 420 419 421 static sos_ret_t dev_zero_fs_write(struct sos_ 420 static sos_ret_t dev_zero_fs_write(struct sos_fs_opened_file *this, 422 sos_uaddr_t 421 sos_uaddr_t src_buf, 423 sos_size_t 422 sos_size_t * /* in/out */len) 424 { 423 { 425 /* Artificiallly update the position in the 424 /* Artificiallly update the position in the "file" */ 426 this->position += *len; 425 this->position += *len; 427 return SOS_OK; 426 return SOS_OK; 428 } 427 } 429 428 430 429 431 static sos_ret_t dev_zero_fs_mmap(struct sos_f 430 static sos_ret_t dev_zero_fs_mmap(struct sos_fs_opened_file *this, 432 sos_uaddr_t 431 sos_uaddr_t *uaddr, sos_size_t size, 433 sos_ui32_t a 432 sos_ui32_t access_rights, 434 sos_ui32_t f 433 sos_ui32_t flags, 435 sos_luoffset 434 sos_luoffset_t offset) 436 { 435 { 437 return sos_dev_zero_map(sos_process_get_addr 436 return sos_dev_zero_map(sos_process_get_address_space(this->owner), 438 uaddr, size, access_ 437 uaddr, size, access_rights, flags); 439 } 438 } 440 439 441 440 442 static struct sos_chardev_ops dev_zero_fs_ops 441 static struct sos_chardev_ops dev_zero_fs_ops 443 = (struct sos_chardev_ops) { 442 = (struct sos_chardev_ops) { 444 .open = dev_zero_fs_open, 443 .open = dev_zero_fs_open, 445 .close = NULL, 444 .close = NULL, 446 .seek = dev_zero_fs_seek, 445 .seek = dev_zero_fs_seek, 447 .read = dev_zero_fs_read, 446 .read = dev_zero_fs_read, 448 .write = dev_zero_fs_write, 447 .write = dev_zero_fs_write, 449 .mmap = dev_zero_fs_mmap, 448 .mmap = dev_zero_fs_mmap, 450 .fcntl = NULL, 449 .fcntl = NULL, 451 .ioctl = NULL 450 .ioctl = NULL 452 }; 451 };
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