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001 /* Copyright (C) 2005 David Decotigny 001 /* Copyright (C) 2005 David Decotigny 002 Copyright (C) 2000-2004, The KOS team 002 Copyright (C) 2000-2004, The KOS team 003 003 004 This program is free software; you can redi 004 This program is free software; you can redistribute it and/or 005 modify it under the terms of the GNU Genera 005 modify it under the terms of the GNU General Public License 006 as published by the Free Software Foundatio 006 as published by the Free Software Foundation; either version 2 007 of the License, or (at your option) any lat 007 of the License, or (at your option) any later version. 008 008 009 This program is distributed in the hope tha 009 This program is distributed in the hope that it will be useful, 010 but WITHOUT ANY WARRANTY; without even the 010 but WITHOUT ANY WARRANTY; without even the implied warranty of 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR 011 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 012 GNU General Public License for more details 012 GNU General Public License for more details. 013 013 014 You should have received a copy of the GNU 014 You should have received a copy of the GNU General Public License 015 along with this program; if not, write to t 015 along with this program; if not, write to the Free Software 016 Foundation, Inc., 59 Temple Place - Suite 3 016 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 017 USA. 017 USA. 018 */ 018 */ 019 019 020 020 021 #include <sos/assert.h> 021 #include <sos/assert.h> 022 #include <sos/klibc.h> 022 #include <sos/klibc.h> 023 #include <drivers/bochs.h> 023 #include <drivers/bochs.h> 024 #include <drivers/x86_videomem.h> 024 #include <drivers/x86_videomem.h> 025 #include <hwcore/segment.h> 025 #include <hwcore/segment.h> 026 #include <hwcore/gdt.h> 026 #include <hwcore/gdt.h> 027 #include <sos/uaccess.h> 027 #include <sos/uaccess.h> 028 028 029 #include "cpu_context.h" 029 #include "cpu_context.h" 030 030 031 031 032 /** 032 /** 033 * Here is the definition of a CPU context for 033 * Here is the definition of a CPU context for IA32 processors. This 034 * is a SOS convention, not a specification gi 034 * is a SOS convention, not a specification given by the IA32 035 * spec. However there is a strong constraint 035 * spec. However there is a strong constraint related to the x86 036 * interrupt handling specification: the top o 036 * interrupt handling specification: the top of the stack MUST be 037 * compatible with the 'iret' instruction, ie 037 * compatible with the 'iret' instruction, ie there must be the 038 * err_code (might be 0), eip, cs and eflags o 038 * err_code (might be 0), eip, cs and eflags of the destination 039 * context in that order (see Intel x86 specs 039 * context in that order (see Intel x86 specs vol 3, figure 5-4). 040 * 040 * 041 * @note IMPORTANT: This definition MUST be co 041 * @note IMPORTANT: This definition MUST be consistent with the way 042 * the registers are stored on the stack in 042 * the registers are stored on the stack in 043 * irq_wrappers.S/exception_wrappers.S !!! Hen 043 * irq_wrappers.S/exception_wrappers.S !!! Hence the constraint above. 044 */ 044 */ 045 struct sos_cpu_state { 045 struct sos_cpu_state { 046 /* (Lower addresses) */ 046 /* (Lower addresses) */ 047 047 048 /* These are SOS convention */ 048 /* These are SOS convention */ 049 sos_ui16_t gs; 049 sos_ui16_t gs; 050 sos_ui16_t fs; 050 sos_ui16_t fs; 051 sos_ui16_t es; 051 sos_ui16_t es; 052 sos_ui16_t ds; 052 sos_ui16_t ds; 053 sos_ui16_t cpl0_ss; /* This is ALWAYS the S 053 sos_ui16_t cpl0_ss; /* This is ALWAYS the Stack Segment of the 054 Kernel context (CPL0 054 Kernel context (CPL0) of the interrupted 055 thread, even for a u 055 thread, even for a user thread */ 056 sos_ui16_t alignment_padding; /* unused */ 056 sos_ui16_t alignment_padding; /* unused */ 057 sos_ui32_t eax; 057 sos_ui32_t eax; 058 sos_ui32_t ebx; 058 sos_ui32_t ebx; 059 sos_ui32_t ecx; 059 sos_ui32_t ecx; 060 sos_ui32_t edx; 060 sos_ui32_t edx; 061 sos_ui32_t esi; 061 sos_ui32_t esi; 062 sos_ui32_t edi; 062 sos_ui32_t edi; 063 sos_ui32_t ebp; 063 sos_ui32_t ebp; 064 064 065 /* MUST NEVER CHANGE (dependent on the IA32 065 /* MUST NEVER CHANGE (dependent on the IA32 iret instruction) */ 066 sos_ui32_t error_code; 066 sos_ui32_t error_code; 067 sos_vaddr_t eip; 067 sos_vaddr_t eip; 068 sos_ui32_t cs; /* 32bits according to the s 068 sos_ui32_t cs; /* 32bits according to the specs ! However, the CS 069 register is really 16bits 069 register is really 16bits long */ 070 sos_ui32_t eflags; 070 sos_ui32_t eflags; 071 071 072 /* (Higher addresses) */ 072 /* (Higher addresses) */ 073 } __attribute__((packed)); 073 } __attribute__((packed)); 074 074 075 075 076 /** 076 /** 077 * The CS value pushed on the stack by the CPU 077 * The CS value pushed on the stack by the CPU upon interrupt, and 078 * needed by the iret instruction, is 32bits l 078 * needed by the iret instruction, is 32bits long while the real CPU 079 * CS register is 16bits only: this macro simp 079 * CS register is 16bits only: this macro simply retrieves the CPU 080 * "CS" register value from the CS value pushe 080 * "CS" register value from the CS value pushed on the stack by the 081 * CPU upon interrupt. 081 * CPU upon interrupt. 082 * 082 * 083 * The remaining 16bits pushed by the CPU shou 083 * The remaining 16bits pushed by the CPU should be considered 084 * "reserved" and architecture dependent. IMHO 084 * "reserved" and architecture dependent. IMHO, the specs don't say 085 * anything about them. Considering that some 085 * anything about them. Considering that some architectures generate 086 * non-zero values for these 16bits (at least 086 * non-zero values for these 16bits (at least Cyrix), we'd better 087 * ignore them. 087 * ignore them. 088 */ 088 */ 089 #define GET_CPU_CS_REGISTER_VALUE(pushed_ui32_ 089 #define GET_CPU_CS_REGISTER_VALUE(pushed_ui32_cs_value) \ 090 ( (pushed_ui32_cs_value) & 0xffff ) 090 ( (pushed_ui32_cs_value) & 0xffff ) 091 091 092 092 093 /** 093 /** 094 * Structure of an interrupted Kernel thread's 094 * Structure of an interrupted Kernel thread's context 095 */ 095 */ 096 struct sos_cpu_kstate 096 struct sos_cpu_kstate 097 { 097 { 098 struct sos_cpu_state regs; 098 struct sos_cpu_state regs; 099 } __attribute__((packed)); 099 } __attribute__((packed)); 100 100 101 101 102 /** 102 /** 103 * Structure of an interrupted User thread's c 103 * Structure of an interrupted User thread's context. This is almost 104 * the same as a kernel context, except that 2 104 * the same as a kernel context, except that 2 additional values are 105 * pushed on the stack before the eflags/cs/ei 105 * pushed on the stack before the eflags/cs/eip of the interrupted 106 * context: the stack configuration of the int 106 * context: the stack configuration of the interrupted user context. 107 * 107 * 108 * @see Section 6.4.1 of Intel x86 vol 1 108 * @see Section 6.4.1 of Intel x86 vol 1 109 */ 109 */ 110 struct sos_cpu_ustate 110 struct sos_cpu_ustate 111 { 111 { 112 struct sos_cpu_state regs; 112 struct sos_cpu_state regs; 113 struct 113 struct 114 { 114 { 115 sos_ui32_t cpl3_esp; 115 sos_ui32_t cpl3_esp; 116 sos_ui16_t cpl3_ss; 116 sos_ui16_t cpl3_ss; 117 }; 117 }; 118 } __attribute__((packed)); 118 } __attribute__((packed)); 119 119 120 120 121 /* 121 /* 122 * Structure of a Task State Segment on the x8 122 * Structure of a Task State Segment on the x86 Architecture. 123 * 123 * 124 * @see Intel x86 spec vol 3, figure 6-2 124 * @see Intel x86 spec vol 3, figure 6-2 125 * 125 * 126 * @note Such a data structure should not cros 126 * @note Such a data structure should not cross any page boundary (see 127 * end of section 6.2.1 of Intel spec vol 3). 127 * end of section 6.2.1 of Intel spec vol 3). This is the reason why 128 * we tell gcc to align it on a 128B boundary 128 * we tell gcc to align it on a 128B boundary (its size is 104B, which 129 * is <= 128). 129 * is <= 128). 130 */ 130 */ 131 struct x86_tss { 131 struct x86_tss { 132 132 133 /** 133 /** 134 * Intel provides a way for a task to switch 134 * Intel provides a way for a task to switch to another in an 135 * automatic way (call gates). In this case, 135 * automatic way (call gates). In this case, the back_link field 136 * stores the source TSS of the context swit 136 * stores the source TSS of the context switch. This allows to 137 * easily implement coroutines, task backtra 137 * easily implement coroutines, task backtracking, ... In SOS we 138 * don't use TSS for the context switch purp 138 * don't use TSS for the context switch purpouse, so we always 139 * ignore this field. 139 * ignore this field. 140 * (+0) 140 * (+0) 141 */ 141 */ 142 sos_ui16_t back_link; 142 sos_ui16_t back_link; 143 143 144 sos_ui16_t reserved1; 144 sos_ui16_t reserved1; 145 145 146 /* CPL0 saved context. (+4) */ 146 /* CPL0 saved context. (+4) */ 147 sos_vaddr_t esp0; 147 sos_vaddr_t esp0; 148 sos_ui16_t ss0; 148 sos_ui16_t ss0; 149 149 150 sos_ui16_t reserved2; 150 sos_ui16_t reserved2; 151 151 152 /* CPL1 saved context. (+12) */ 152 /* CPL1 saved context. (+12) */ 153 sos_vaddr_t esp1; 153 sos_vaddr_t esp1; 154 sos_ui16_t ss1; 154 sos_ui16_t ss1; 155 155 156 sos_ui16_t reserved3; 156 sos_ui16_t reserved3; 157 157 158 /* CPL2 saved context. (+20) */ 158 /* CPL2 saved context. (+20) */ 159 sos_vaddr_t esp2; 159 sos_vaddr_t esp2; 160 sos_ui16_t ss2; 160 sos_ui16_t ss2; 161 161 162 sos_ui16_t reserved4; 162 sos_ui16_t reserved4; 163 163 164 /* Interrupted context's saved registers. (+ 164 /* Interrupted context's saved registers. (+28) */ 165 sos_vaddr_t cr3; 165 sos_vaddr_t cr3; 166 sos_vaddr_t eip; 166 sos_vaddr_t eip; 167 sos_ui32_t eflags; 167 sos_ui32_t eflags; 168 sos_ui32_t eax; 168 sos_ui32_t eax; 169 sos_ui32_t ecx; 169 sos_ui32_t ecx; 170 sos_ui32_t edx; 170 sos_ui32_t edx; 171 sos_ui32_t ebx; 171 sos_ui32_t ebx; 172 sos_ui32_t esp; 172 sos_ui32_t esp; 173 sos_ui32_t ebp; 173 sos_ui32_t ebp; 174 sos_ui32_t esi; 174 sos_ui32_t esi; 175 sos_ui32_t edi; 175 sos_ui32_t edi; 176 176 177 /* +72 */ 177 /* +72 */ 178 sos_ui16_t es; 178 sos_ui16_t es; 179 sos_ui16_t reserved5; 179 sos_ui16_t reserved5; 180 180 181 /* +76 */ 181 /* +76 */ 182 sos_ui16_t cs; 182 sos_ui16_t cs; 183 sos_ui16_t reserved6; 183 sos_ui16_t reserved6; 184 184 185 /* +80 */ 185 /* +80 */ 186 sos_ui16_t ss; 186 sos_ui16_t ss; 187 sos_ui16_t reserved7; 187 sos_ui16_t reserved7; 188 188 189 /* +84 */ 189 /* +84 */ 190 sos_ui16_t ds; 190 sos_ui16_t ds; 191 sos_ui16_t reserved8; 191 sos_ui16_t reserved8; 192 192 193 /* +88 */ 193 /* +88 */ 194 sos_ui16_t fs; 194 sos_ui16_t fs; 195 sos_ui16_t reserved9; 195 sos_ui16_t reserved9; 196 196 197 /* +92 */ 197 /* +92 */ 198 sos_ui16_t gs; 198 sos_ui16_t gs; 199 sos_ui16_t reserved10; 199 sos_ui16_t reserved10; 200 200 201 /* +96 */ 201 /* +96 */ 202 sos_ui16_t ldtr; 202 sos_ui16_t ldtr; 203 sos_ui16_t reserved11; 203 sos_ui16_t reserved11; 204 204 205 /* +100 */ 205 /* +100 */ 206 sos_ui16_t debug_trap_flag :1; 206 sos_ui16_t debug_trap_flag :1; 207 sos_ui16_t reserved12 :15; 207 sos_ui16_t reserved12 :15; 208 sos_ui16_t iomap_base_addr; 208 sos_ui16_t iomap_base_addr; 209 209 210 /* 104 */ 210 /* 104 */ 211 } __attribute__((packed, aligned(128))); 211 } __attribute__((packed, aligned(128))); 212 212 213 213 214 static struct x86_tss kernel_tss; 214 static struct x86_tss kernel_tss; 215 215 216 216 217 sos_ret_t sos_cpu_context_subsystem_setup() 217 sos_ret_t sos_cpu_context_subsystem_setup() 218 { 218 { 219 /* Reset the kernel TSS */ 219 /* Reset the kernel TSS */ 220 memset(&kernel_tss, 0x0, sizeof(kernel_tss)) 220 memset(&kernel_tss, 0x0, sizeof(kernel_tss)); 221 221 222 /** 222 /** 223 * Now setup the kernel TSS. 223 * Now setup the kernel TSS. 224 * 224 * 225 * Considering the privilege change method w 225 * Considering the privilege change method we choose (cpl3 -> cpl0 226 * through a software interrupt), we don't n 226 * through a software interrupt), we don't need to initialize a 227 * full-fledged TSS. See section 6.4.1 of In 227 * full-fledged TSS. See section 6.4.1 of Intel x86 vol 1. Actually, 228 * only a correct value for the kernel esp a 228 * only a correct value for the kernel esp and ss are required (aka 229 * "ss0" and "esp0" fields). Since the esp0 229 * "ss0" and "esp0" fields). Since the esp0 will have to be updated 230 * at privilege change time, we don't have t 230 * at privilege change time, we don't have to set it up now. 231 */ 231 */ 232 kernel_tss.ss0 = SOS_BUILD_SEGMENT_REG_VALUE 232 kernel_tss.ss0 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KDATA); 233 233 234 /* Register this TSS into the gdt */ 234 /* Register this TSS into the gdt */ 235 sos_gdt_register_kernel_tss((sos_vaddr_t) &k 235 sos_gdt_register_kernel_tss((sos_vaddr_t) &kernel_tss); 236 236 237 return SOS_OK; 237 return SOS_OK; 238 } 238 } 239 239 240 240 241 /** 241 /** 242 * THE main operation of a kernel thread. This 242 * THE main operation of a kernel thread. This routine calls the 243 * kernel thread function start_func and calls 243 * kernel thread function start_func and calls exit_func when 244 * start_func returns. 244 * start_func returns. 245 */ 245 */ 246 static void core_routine (sos_cpu_kstate_funct 246 static void core_routine (sos_cpu_kstate_function_arg1_t *start_func, 247 sos_ui32_t start_arg 247 sos_ui32_t start_arg, 248 sos_cpu_kstate_funct 248 sos_cpu_kstate_function_arg1_t *exit_func, 249 sos_ui32_t exit_arg) 249 sos_ui32_t exit_arg) 250 __attribute__((noreturn)); 250 __attribute__((noreturn)); 251 251 252 static void core_routine (sos_cpu_kstate_funct 252 static void core_routine (sos_cpu_kstate_function_arg1_t *start_func, 253 sos_ui32_t start_arg 253 sos_ui32_t start_arg, 254 sos_cpu_kstate_funct 254 sos_cpu_kstate_function_arg1_t *exit_func, 255 sos_ui32_t exit_arg) 255 sos_ui32_t exit_arg) 256 { 256 { 257 start_func(start_arg); 257 start_func(start_arg); 258 exit_func(exit_arg); 258 exit_func(exit_arg); 259 259 260 SOS_ASSERT_FATAL(! "The exit function of the 260 SOS_ASSERT_FATAL(! "The exit function of the thread should NOT return !"); 261 for(;;); 261 for(;;); 262 } 262 } 263 263 264 264 265 sos_ret_t sos_cpu_kstate_init(struct sos_cpu_s 265 sos_ret_t sos_cpu_kstate_init(struct sos_cpu_state **ctxt, 266 sos_cpu_kstate_f 266 sos_cpu_kstate_function_arg1_t *start_func, 267 sos_ui32_t star 267 sos_ui32_t start_arg, 268 sos_vaddr_t stac 268 sos_vaddr_t stack_bottom, 269 sos_size_t stac 269 sos_size_t stack_size, 270 sos_cpu_kstate_f 270 sos_cpu_kstate_function_arg1_t *exit_func, 271 sos_ui32_t exit 271 sos_ui32_t exit_arg) 272 { 272 { 273 /* We are initializing a Kernel thread's con 273 /* We are initializing a Kernel thread's context */ 274 struct sos_cpu_kstate *kctxt; 274 struct sos_cpu_kstate *kctxt; 275 275 276 /* This is a critical internal function, so 276 /* This is a critical internal function, so that it is assumed that 277 the caller knows what he does: we legitim 277 the caller knows what he does: we legitimally assume that values 278 for ctxt, start_func, stack_* and exit_fu 278 for ctxt, start_func, stack_* and exit_func are allways VALID ! */ 279 279 280 /* Setup the stack. 280 /* Setup the stack. 281 * 281 * 282 * On x86, the stack goes downward. Each fra 282 * On x86, the stack goes downward. Each frame is configured this 283 * way (higher addresses first): 283 * way (higher addresses first): 284 * 284 * 285 * - (optional unused space. As of gcc 3.3, 285 * - (optional unused space. As of gcc 3.3, this space is 24 bytes) 286 * - arg n 286 * - arg n 287 * - arg n-1 287 * - arg n-1 288 * - ... 288 * - ... 289 * - arg 1 289 * - arg 1 290 * - return instruction address: The addres 290 * - return instruction address: The address the function returns to 291 * once finished 291 * once finished 292 * - local variables 292 * - local variables 293 * 293 * 294 * The remaining of the code should be read 294 * The remaining of the code should be read from the end upward to 295 * understand how the processor will handle 295 * understand how the processor will handle it. 296 */ 296 */ 297 297 298 sos_vaddr_t tmp_vaddr = stack_bottom + stack 298 sos_vaddr_t tmp_vaddr = stack_bottom + stack_size; 299 sos_ui32_t *stack = (sos_ui32_t*)tmp_vaddr; 299 sos_ui32_t *stack = (sos_ui32_t*)tmp_vaddr; 300 300 301 /* If needed, poison the stack */ 301 /* If needed, poison the stack */ 302 #ifdef SOS_CPU_STATE_DETECT_UNINIT_KERNEL_VARS 302 #ifdef SOS_CPU_STATE_DETECT_UNINIT_KERNEL_VARS 303 memset((void*)stack_bottom, SOS_CPU_STATE_ST 303 memset((void*)stack_bottom, SOS_CPU_STATE_STACK_POISON, stack_size); 304 #elif defined(SOS_CPU_STATE_DETECT_KERNEL_STAC 304 #elif defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) 305 sos_cpu_state_prepare_detect_kernel_stack_ov 305 sos_cpu_state_prepare_detect_kernel_stack_overflow(stack_bottom, stack_size); 306 #endif 306 #endif 307 307 308 /* Simulate a call to the core_routine() fun 308 /* Simulate a call to the core_routine() function: prepare its 309 arguments */ 309 arguments */ 310 *(--stack) = exit_arg; 310 *(--stack) = exit_arg; 311 *(--stack) = (sos_ui32_t)exit_func; 311 *(--stack) = (sos_ui32_t)exit_func; 312 *(--stack) = start_arg; 312 *(--stack) = start_arg; 313 *(--stack) = (sos_ui32_t)start_func; 313 *(--stack) = (sos_ui32_t)start_func; 314 *(--stack) = 0; /* Return address of core_ro 314 *(--stack) = 0; /* Return address of core_routine => force page fault */ 315 315 316 /* 316 /* 317 * Setup the initial context structure, so t 317 * Setup the initial context structure, so that the CPU will execute 318 * the function core_routine() once this new 318 * the function core_routine() once this new context has been 319 * restored on CPU 319 * restored on CPU 320 */ 320 */ 321 321 322 /* Compute the base address of the structure 322 /* Compute the base address of the structure, which must be located 323 below the previous elements */ 323 below the previous elements */ 324 tmp_vaddr = ((sos_vaddr_t)stack) - sizeof(s 324 tmp_vaddr = ((sos_vaddr_t)stack) - sizeof(struct sos_cpu_kstate); 325 kctxt = (struct sos_cpu_kstate*)tmp_vaddr; 325 kctxt = (struct sos_cpu_kstate*)tmp_vaddr; 326 326 327 /* Initialize the CPU context structure */ 327 /* Initialize the CPU context structure */ 328 memset(kctxt, 0x0, sizeof(struct sos_cpu_kst 328 memset(kctxt, 0x0, sizeof(struct sos_cpu_kstate)); 329 329 330 /* Tell the CPU context structure that the f 330 /* Tell the CPU context structure that the first instruction to 331 execute will be that of the core_routine( 331 execute will be that of the core_routine() function */ 332 kctxt->regs.eip = (sos_ui32_t)core_routine; 332 kctxt->regs.eip = (sos_ui32_t)core_routine; 333 333 334 /* Setup the segment registers */ 334 /* Setup the segment registers */ 335 kctxt->regs.cs 335 kctxt->regs.cs 336 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SO 336 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KCODE); /* Code */ 337 kctxt->regs.ds 337 kctxt->regs.ds 338 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SO 338 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KDATA); /* Data */ 339 kctxt->regs.es 339 kctxt->regs.es 340 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SO 340 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KDATA); /* Data */ 341 kctxt->regs.cpl0_ss 341 kctxt->regs.cpl0_ss 342 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SO 342 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KDATA); /* Stack */ 343 /* fs and gs unused for the moment. */ 343 /* fs and gs unused for the moment. */ 344 344 345 /* The newly created context is initially in 345 /* The newly created context is initially interruptible */ 346 kctxt->regs.eflags = (1 << 9); /* set IF bit 346 kctxt->regs.eflags = (1 << 9); /* set IF bit */ 347 347 348 /* Finally, update the generic kernel/user t 348 /* Finally, update the generic kernel/user thread context */ 349 *ctxt = (struct sos_cpu_state*) kctxt; 349 *ctxt = (struct sos_cpu_state*) kctxt; 350 350 351 return SOS_OK; 351 return SOS_OK; 352 } 352 } 353 353 354 354 355 /** !! 355 sos_ret_t sos_cpu_ustate_init(struct sos_cpu_state **ctxt, 356 * Helper function to create a new user thread !! 356 sos_uaddr_t user_start_PC, 357 * model_uctxt is NON NULL, the new user conte !! 357 sos_ui32_t user_start_arg1, 358 * model_uctxt, otherwise the SP/PC registers !! 358 sos_ui32_t user_start_arg2, 359 * user_initial_SP/PC arguments !! 359 sos_uaddr_t user_initial_SP, 360 */ !! 360 sos_vaddr_t kernel_stack_bottom, 361 static sos_ret_t cpu_ustate_init(struct sos_cp !! 361 sos_size_t kernel_stack_size) 362 const struct << 363 sos_uaddr_t << 364 sos_ui32_t << 365 sos_ui32_t << 366 sos_uaddr_t << 367 sos_vaddr_t << 368 sos_size_t << 369 { 362 { 370 /* We are initializing a User thread's conte 363 /* We are initializing a User thread's context */ 371 struct sos_cpu_ustate *uctxt; 364 struct sos_cpu_ustate *uctxt; 372 365 373 /* This is a critical internal function, so 366 /* This is a critical internal function, so that it is assumed that 374 the caller knows what he does: we legitim 367 the caller knows what he does: we legitimally assume that values 375 for ctxt, etc. are allways VALID ! */ 368 for ctxt, etc. are allways VALID ! */ 376 369 377 /* Compute the address of the CPU state to r 370 /* Compute the address of the CPU state to restore on CPU when 378 switching to this new user thread */ 371 switching to this new user thread */ 379 sos_vaddr_t uctxt_vaddr = kernel_stack_botto 372 sos_vaddr_t uctxt_vaddr = kernel_stack_bottom 380 + kernel_stack_si 373 + kernel_stack_size 381 - sizeof(struct s 374 - sizeof(struct sos_cpu_ustate); 382 uctxt = (struct sos_cpu_ustate*)uctxt_vaddr; 375 uctxt = (struct sos_cpu_ustate*)uctxt_vaddr; 383 376 384 if (model_uctxt && !sos_cpu_context_is_in_us << 385 return -SOS_EINVAL; << 386 << 387 /* If needed, poison the kernel stack */ 377 /* If needed, poison the kernel stack */ 388 #ifdef SOS_CPU_STATE_DETECT_UNINIT_KERNEL_VARS 378 #ifdef SOS_CPU_STATE_DETECT_UNINIT_KERNEL_VARS 389 memset((void*)kernel_stack_bottom, 379 memset((void*)kernel_stack_bottom, 390 SOS_CPU_STATE_STACK_POISON, 380 SOS_CPU_STATE_STACK_POISON, 391 kernel_stack_size); 381 kernel_stack_size); 392 #elif defined(SOS_CPU_STATE_DETECT_KERNEL_STAC 382 #elif defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) 393 sos_cpu_state_prepare_detect_kernel_stack_ov 383 sos_cpu_state_prepare_detect_kernel_stack_overflow(kernel_stack_bottom, 394 384 kernel_stack_size); 395 #endif 385 #endif 396 386 397 /* 387 /* 398 * Setup the initial context structure, so t 388 * Setup the initial context structure, so that the CPU will restore 399 * the initial registers' value for the user 389 * the initial registers' value for the user thread. The 400 * user thread argument is passed in the EAX 390 * user thread argument is passed in the EAX register. 401 */ 391 */ 402 392 403 /* Initialize the CPU context structure */ !! 393 memset(uctxt, 0x0, sizeof(struct sos_cpu_ustate)); 404 if (! model_uctxt) !! 394 405 { !! 395 /* Tell the CPU context structure that the first instruction to 406 memset(uctxt, 0x0, sizeof(struct sos_cpu !! 396 execute will be located at user_start_PC (in user space) */ 407 !! 397 uctxt->regs.eip = (sos_ui32_t)user_start_PC; 408 /* Tell the CPU context structure that t !! 398 409 execute will be located at user_start !! 399 /* Tell the CPU where will be the user stack */ 410 uctxt->regs.eip = (sos_ui32_t)user_start !! 400 uctxt->cpl3_esp = user_initial_SP; 411 << 412 /* Tell the CPU where will be the user s << 413 uctxt->cpl3_esp = user_initial_SP; << 414 } << 415 else << 416 memcpy(uctxt, model_uctxt, sizeof(struct s << 417 401 418 /* The parameter to the start function is no 402 /* The parameter to the start function is not passed by the stack to 419 avoid a possible page fault */ 403 avoid a possible page fault */ 420 uctxt->regs.eax = user_start_arg1; 404 uctxt->regs.eax = user_start_arg1; 421 !! 405 uctxt->regs.ebx = user_start_arg2; 422 /* Optional additional argument for non-dupl << 423 if (! model_uctxt) << 424 uctxt->regs.ebx = user_start_arg2; << 425 406 426 /* Setup the segment registers */ 407 /* Setup the segment registers */ 427 uctxt->regs.cs 408 uctxt->regs.cs 428 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 409 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UCODE); /* Code */ 429 uctxt->regs.ds 410 uctxt->regs.ds 430 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 411 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UDATA); /* Data */ 431 uctxt->regs.es 412 uctxt->regs.es 432 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 413 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UDATA); /* Data */ 433 uctxt->cpl3_ss 414 uctxt->cpl3_ss 434 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 415 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UDATA); /* User Stack */ 435 416 436 /* We need also to update the segment for th 417 /* We need also to update the segment for the kernel stack 437 segment. It will be used when this contex 418 segment. It will be used when this context will be restored on 438 CPU: initially it will be executing in ke 419 CPU: initially it will be executing in kernel mode and will 439 switch immediatly to user mode */ 420 switch immediatly to user mode */ 440 uctxt->regs.cpl0_ss 421 uctxt->regs.cpl0_ss 441 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SO 422 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KDATA); /* Kernel Stack */ 442 423 443 /* fs and gs unused for the moment. */ 424 /* fs and gs unused for the moment. */ 444 425 445 /* The newly created context is initially in 426 /* The newly created context is initially interruptible */ 446 uctxt->regs.eflags = (1 << 9); /* set IF bit 427 uctxt->regs.eflags = (1 << 9); /* set IF bit */ 447 428 448 /* Finally, update the generic kernel/user t 429 /* Finally, update the generic kernel/user thread context */ 449 *ctxt = (struct sos_cpu_state*) uctxt; 430 *ctxt = (struct sos_cpu_state*) uctxt; 450 431 451 return SOS_OK; 432 return SOS_OK; 452 } << 453 << 454 << 455 sos_ret_t sos_cpu_ustate_init(struct sos_cpu_s << 456 sos_uaddr_t use << 457 sos_ui32_t use << 458 sos_ui32_t use << 459 sos_uaddr_t use << 460 sos_vaddr_t ker << 461 sos_size_t ker << 462 { << 463 return cpu_ustate_init(ctxt, NULL, << 464 user_start_PC, << 465 user_start_arg1, user << 466 user_initial_SP, << 467 kernel_stack_bottom, << 468 } << 469 << 470 << 471 sos_ret_t sos_cpu_ustate_duplicate(struct sos_ << 472 const struc << 473 sos_ui32_t << 474 sos_vaddr_t << 475 sos_size_t << 476 { << 477 return cpu_ustate_init(ctxt, model_uctxt, << 478 /* ignored */0, << 479 user_retval, /* ignor << 480 /* ignored */0, << 481 kernel_stack_bottom, << 482 } 433 } 483 434 484 435 485 sos_ret_t 436 sos_ret_t 486 sos_cpu_context_is_in_user_mode(const struct s 437 sos_cpu_context_is_in_user_mode(const struct sos_cpu_state *ctxt) 487 { 438 { 488 /* An interrupted user thread has its CS reg 439 /* An interrupted user thread has its CS register set to that of the 489 User code segment */ 440 User code segment */ 490 switch (GET_CPU_CS_REGISTER_VALUE(ctxt->cs)) 441 switch (GET_CPU_CS_REGISTER_VALUE(ctxt->cs)) 491 { 442 { 492 case SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, 443 case SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UCODE): 493 return TRUE; 444 return TRUE; 494 break; 445 break; 495 446 496 case SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, 447 case SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KCODE): 497 return FALSE; 448 return FALSE; 498 break; 449 break; 499 450 500 default: 451 default: 501 SOS_FATAL_ERROR("Invalid saved context C 452 SOS_FATAL_ERROR("Invalid saved context Code segment register: 0x%x (k=%x, u=%x) !", 502 (unsigned) GET_CPU_CS_RE 453 (unsigned) GET_CPU_CS_REGISTER_VALUE(ctxt->cs), 503 SOS_BUILD_SEGMENT_REG_VA 454 SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KCODE), 504 SOS_BUILD_SEGMENT_REG_VA 455 SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UCODE)); 505 break; 456 break; 506 } 457 } 507 458 508 /* Should never get here */ 459 /* Should never get here */ 509 return -SOS_EFATAL; 460 return -SOS_EFATAL; 510 } 461 } 511 462 512 463 513 #if defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_ 464 #if defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) 514 void 465 void 515 sos_cpu_state_prepare_detect_kernel_stack_over 466 sos_cpu_state_prepare_detect_kernel_stack_overflow(const struct sos_cpu_state *ctxt, 516 467 sos_vaddr_t stack_bottom, 517 468 sos_size_t stack_size) 518 { 469 { 519 sos_size_t poison_size = SOS_CPU_STATE_DETEC 470 sos_size_t poison_size = SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW; 520 if (poison_size > stack_size) 471 if (poison_size > stack_size) 521 poison_size = stack_size; 472 poison_size = stack_size; 522 473 523 memset((void*)stack_bottom, SOS_CPU_STATE_ST 474 memset((void*)stack_bottom, SOS_CPU_STATE_STACK_POISON, poison_size); 524 } 475 } 525 476 526 477 527 void 478 void 528 sos_cpu_state_detect_kernel_stack_overflow(con 479 sos_cpu_state_detect_kernel_stack_overflow(const struct sos_cpu_state *ctxt, 529 sos 480 sos_vaddr_t stack_bottom, 530 sos 481 sos_size_t stack_size) 531 { 482 { 532 unsigned char *c; 483 unsigned char *c; 533 int i; 484 int i; 534 485 535 /* On SOS, "ctxt" corresponds to the address 486 /* On SOS, "ctxt" corresponds to the address of the esp register of 536 the saved context in Kernel mode (always, 487 the saved context in Kernel mode (always, even for the interrupted 537 context of a user thread). Here we make s 488 context of a user thread). Here we make sure that this stack 538 pointer is within the allowed stack area 489 pointer is within the allowed stack area */ 539 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) >= stac 490 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) >= stack_bottom); 540 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) + sizeo 491 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) + sizeof(struct sos_cpu_kstate) 541 <= stack_bottom + stack_siz 492 <= stack_bottom + stack_size); 542 493 543 /* Check that the bottom of the stack has no 494 /* Check that the bottom of the stack has not been altered */ 544 for (c = (unsigned char*) stack_bottom, i = 495 for (c = (unsigned char*) stack_bottom, i = 0 ; 545 (i < SOS_CPU_STATE_DETECT_KERNEL_STACK_ 496 (i < SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) && (i < stack_size) ; 546 c++, i++) 497 c++, i++) 547 { 498 { 548 SOS_ASSERT_FATAL(SOS_CPU_STATE_STACK_POI 499 SOS_ASSERT_FATAL(SOS_CPU_STATE_STACK_POISON == *c); 549 } 500 } 550 } 501 } 551 #endif 502 #endif 552 503 553 504 554 /* =========================================== 505 /* ======================================================================= 555 * Public Accessor functions 506 * Public Accessor functions 556 */ 507 */ 557 508 558 509 559 sos_vaddr_t sos_cpu_context_get_PC(const struc 510 sos_vaddr_t sos_cpu_context_get_PC(const struct sos_cpu_state *ctxt) 560 { 511 { 561 SOS_ASSERT_FATAL(NULL != ctxt); 512 SOS_ASSERT_FATAL(NULL != ctxt); 562 513 563 /* This is the PC of the interrupted context 514 /* This is the PC of the interrupted context (ie kernel or user 564 context). */ 515 context). */ 565 return ctxt->eip; 516 return ctxt->eip; 566 } 517 } 567 518 568 519 569 sos_vaddr_t sos_cpu_context_get_SP(const struc 520 sos_vaddr_t sos_cpu_context_get_SP(const struct sos_cpu_state *ctxt) 570 { 521 { 571 SOS_ASSERT_FATAL(NULL != ctxt); 522 SOS_ASSERT_FATAL(NULL != ctxt); 572 523 573 /* 'ctxt' corresponds to the SP of the inter 524 /* 'ctxt' corresponds to the SP of the interrupted context, in Kernel 574 mode. We have to test whether the origina 525 mode. We have to test whether the original interrupted context 575 was that of a kernel or user thread */ 526 was that of a kernel or user thread */ 576 if (TRUE == sos_cpu_context_is_in_user_mode( 527 if (TRUE == sos_cpu_context_is_in_user_mode(ctxt)) 577 { 528 { 578 struct sos_cpu_ustate * uctxt = (struct 529 struct sos_cpu_ustate * uctxt = (struct sos_cpu_ustate*)ctxt; 579 return uctxt->cpl3_esp; 530 return uctxt->cpl3_esp; 580 } 531 } 581 532 582 /* On SOS, "ctxt" corresponds to the address 533 /* On SOS, "ctxt" corresponds to the address of the esp register of 583 the saved context in Kernel mode (always, 534 the saved context in Kernel mode (always, even for the interrupted 584 context of a user thread). */ 535 context of a user thread). */ 585 return (sos_vaddr_t)ctxt; 536 return (sos_vaddr_t)ctxt; 586 } 537 } 587 538 588 539 589 sos_ret_t 540 sos_ret_t 590 sos_cpu_context_set_EX_return_address(struct s 541 sos_cpu_context_set_EX_return_address(struct sos_cpu_state *ctxt, 591 sos_vadd 542 sos_vaddr_t ret_vaddr) 592 { 543 { 593 ctxt->eip = ret_vaddr; 544 ctxt->eip = ret_vaddr; 594 return SOS_OK; 545 return SOS_OK; 595 } 546 } 596 547 597 548 598 void sos_cpu_context_dump(const struct sos_cpu 549 void sos_cpu_context_dump(const struct sos_cpu_state *ctxt) 599 { 550 { 600 char buf[128]; 551 char buf[128]; 601 552 602 snprintf(buf, sizeof(buf), 553 snprintf(buf, sizeof(buf), 603 "CPU: eip=%x esp0=%x eflags=%x cs=% 554 "CPU: eip=%x esp0=%x eflags=%x cs=%x ds=%x ss0=%x err=%x", 604 (unsigned)ctxt->eip, (unsigned)ctxt 555 (unsigned)ctxt->eip, (unsigned)ctxt, (unsigned)ctxt->eflags, 605 (unsigned)GET_CPU_CS_REGISTER_VALUE 556 (unsigned)GET_CPU_CS_REGISTER_VALUE(ctxt->cs), (unsigned)ctxt->ds, 606 (unsigned)ctxt->cpl0_ss, 557 (unsigned)ctxt->cpl0_ss, 607 (unsigned)ctxt->error_code); 558 (unsigned)ctxt->error_code); 608 if (TRUE == sos_cpu_context_is_in_user_mode( 559 if (TRUE == sos_cpu_context_is_in_user_mode(ctxt)) 609 { 560 { 610 struct sos_cpu_ustate * uctxt = (struct 561 struct sos_cpu_ustate * uctxt = (struct sos_cpu_ustate*)ctxt; 611 snprintf(buf, sizeof(buf), 562 snprintf(buf, sizeof(buf), 612 "%s esp3=%x ss3=%x", 563 "%s esp3=%x ss3=%x", 613 buf, (unsigned)uctxt->cpl3_esp, 564 buf, (unsigned)uctxt->cpl3_esp, (unsigned)uctxt->cpl3_ss); 614 } 565 } 615 else 566 else 616 snprintf(buf, sizeof(buf), "%s [KERNEL MOD 567 snprintf(buf, sizeof(buf), "%s [KERNEL MODE]", buf); 617 568 618 sos_bochs_putstring(buf); sos_bochs_putstrin 569 sos_bochs_putstring(buf); sos_bochs_putstring("\n"); 619 sos_x86_videomem_putstring(23, 0, 570 sos_x86_videomem_putstring(23, 0, 620 SOS_X86_VIDEO_FG_ 571 SOS_X86_VIDEO_FG_BLACK | SOS_X86_VIDEO_BG_LTGRAY, 621 buf); 572 buf); 622 } 573 } 623 574 624 575 625 /* =========================================== 576 /* ======================================================================= 626 * Public Accessor functions TO BE USED ONLY B 577 * Public Accessor functions TO BE USED ONLY BY Exception handlers 627 */ 578 */ 628 579 629 580 630 sos_ui32_t sos_cpu_context_get_EX_info(const s 581 sos_ui32_t sos_cpu_context_get_EX_info(const struct sos_cpu_state *ctxt) 631 { 582 { 632 SOS_ASSERT_FATAL(NULL != ctxt); 583 SOS_ASSERT_FATAL(NULL != ctxt); 633 return ctxt->error_code; 584 return ctxt->error_code; 634 } 585 } 635 586 636 587 637 sos_vaddr_t 588 sos_vaddr_t 638 sos_cpu_context_get_EX_faulting_vaddr(const st 589 sos_cpu_context_get_EX_faulting_vaddr(const struct sos_cpu_state *ctxt) 639 { 590 { 640 sos_ui32_t cr2; 591 sos_ui32_t cr2; 641 592 642 /* 593 /* 643 * See Intel Vol 3 (section 5.14): the addre 594 * See Intel Vol 3 (section 5.14): the address of the faulting 644 * virtual address of a page fault is stored 595 * virtual address of a page fault is stored in the cr2 645 * register. 596 * register. 646 * 597 * 647 * Actually, we do not store the cr2 registe 598 * Actually, we do not store the cr2 register in a saved 648 * kernel thread's context. So we retrieve t 599 * kernel thread's context. So we retrieve the cr2's value directly 649 * from the processor. The value we retrieve 600 * from the processor. The value we retrieve in an exception handler 650 * is actually the correct one because an ex 601 * is actually the correct one because an exception is synchronous 651 * with the code causing the fault, and cann 602 * with the code causing the fault, and cannot be interrupted since 652 * the IDT entries in SOS are "interrupt gat 603 * the IDT entries in SOS are "interrupt gates" (ie IRQ are 653 * disabled). 604 * disabled). 654 */ 605 */ 655 asm volatile ("movl %%cr2, %0" 606 asm volatile ("movl %%cr2, %0" 656 :"=r"(cr2) 607 :"=r"(cr2) 657 : ); 608 : ); 658 609 659 return cr2; 610 return cr2; 660 } 611 } 661 612 662 613 663 /* =========================================== 614 /* ======================================================================= 664 * Public Accessor functions TO BE USED ONLY B 615 * Public Accessor functions TO BE USED ONLY BY the SYSCALL handler 665 */ 616 */ 666 617 667 618 668 /* 619 /* 669 * By convention, the USER SOS programs always 620 * By convention, the USER SOS programs always pass 4 arguments to the 670 * kernel syscall handler: in eax/../edx. For 621 * kernel syscall handler: in eax/../edx. For less arguments, the 671 * unused registers are filled with 0s. For mo 622 * unused registers are filled with 0s. For more arguments, the 4th 672 * syscall parameter gives the address of the 623 * syscall parameter gives the address of the array containing the 673 * remaining arguments. In any case, eax corre 624 * remaining arguments. In any case, eax corresponds to the syscall 674 * IDentifier. 625 * IDentifier. 675 */ 626 */ 676 627 677 628 678 inline 629 inline 679 sos_ret_t sos_syscall_get3args(const struct so 630 sos_ret_t sos_syscall_get3args(const struct sos_cpu_state *user_ctxt, 680 /* out */unsign 631 /* out */unsigned int *arg1, 681 /* out */unsign 632 /* out */unsigned int *arg2, 682 /* out */unsign 633 /* out */unsigned int *arg3) 683 { 634 { 684 *arg1 = user_ctxt->ebx; 635 *arg1 = user_ctxt->ebx; 685 *arg2 = user_ctxt->ecx; 636 *arg2 = user_ctxt->ecx; 686 *arg3 = user_ctxt->edx; 637 *arg3 = user_ctxt->edx; 687 return SOS_OK; 638 return SOS_OK; 688 } 639 } 689 640 690 641 691 sos_ret_t sos_syscall_get1arg(const struct sos 642 sos_ret_t sos_syscall_get1arg(const struct sos_cpu_state *user_ctxt, 692 /* out */unsigne 643 /* out */unsigned int *arg1) 693 { 644 { 694 unsigned int unused; 645 unsigned int unused; 695 return sos_syscall_get3args(user_ctxt, arg1, 646 return sos_syscall_get3args(user_ctxt, arg1, & unused, & unused); 696 } 647 } 697 648 698 649 699 sos_ret_t sos_syscall_get2args(const struct so 650 sos_ret_t sos_syscall_get2args(const struct sos_cpu_state *user_ctxt, 700 /* out */unsign 651 /* out */unsigned int *arg1, 701 /* out */unsign 652 /* out */unsigned int *arg2) 702 { 653 { 703 unsigned int unused; 654 unsigned int unused; 704 return sos_syscall_get3args(user_ctxt, arg1, 655 return sos_syscall_get3args(user_ctxt, arg1, arg2, & unused); 705 } 656 } 706 657 707 658 708 /* 659 /* 709 * sos_syscall_get3args() is defined in cpu_co 660 * sos_syscall_get3args() is defined in cpu_context.c because it needs 710 * to know the structure of a struct spu_state 661 * to know the structure of a struct spu_state 711 */ 662 */ 712 663 713 sos_ret_t sos_syscall_get4args(const struct so 664 sos_ret_t sos_syscall_get4args(const struct sos_cpu_state *user_ctxt, 714 /* out */unsign 665 /* out */unsigned int *arg1, 715 /* out */unsign 666 /* out */unsigned int *arg2, 716 /* out */unsign 667 /* out */unsigned int *arg3, 717 /* out */unsign 668 /* out */unsigned int *arg4) 718 { 669 { 719 sos_uaddr_t uaddr_other_args; 670 sos_uaddr_t uaddr_other_args; 720 unsigned int other_args[2]; 671 unsigned int other_args[2]; 721 sos_ret_t retval; 672 sos_ret_t retval; 722 673 723 /* Retrieve the 3 arguments. The last one is 674 /* Retrieve the 3 arguments. The last one is an array containing the 724 remaining arguments */ 675 remaining arguments */ 725 retval = sos_syscall_get3args(user_ctxt, arg 676 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 726 (unsigned int 677 (unsigned int *)& uaddr_other_args); 727 if (SOS_OK != retval) 678 if (SOS_OK != retval) 728 return retval; 679 return retval; 729 680 730 /* Copy the array containing the remaining a 681 /* Copy the array containing the remaining arguments from user 731 space */ 682 space */ 732 retval = sos_memcpy_from_user((sos_vaddr_t)o 683 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 733 (sos_uaddr_t)u 684 (sos_uaddr_t)uaddr_other_args, 734 sizeof(other_a 685 sizeof(other_args)); 735 if (sizeof(other_args) != retval) 686 if (sizeof(other_args) != retval) 736 return -SOS_EFAULT; 687 return -SOS_EFAULT; 737 688 738 *arg3 = other_args[0]; 689 *arg3 = other_args[0]; 739 *arg4 = other_args[1]; 690 *arg4 = other_args[1]; 740 return SOS_OK; 691 return SOS_OK; 741 } 692 } 742 693 743 694 744 sos_ret_t sos_syscall_get5args(const struct so 695 sos_ret_t sos_syscall_get5args(const struct sos_cpu_state *user_ctxt, 745 /* out */unsign 696 /* out */unsigned int *arg1, 746 /* out */unsign 697 /* out */unsigned int *arg2, 747 /* out */unsign 698 /* out */unsigned int *arg3, 748 /* out */unsign 699 /* out */unsigned int *arg4, 749 /* out */unsign 700 /* out */unsigned int *arg5) 750 { 701 { 751 sos_uaddr_t uaddr_other_args; 702 sos_uaddr_t uaddr_other_args; 752 unsigned int other_args[3]; 703 unsigned int other_args[3]; 753 sos_ret_t retval; 704 sos_ret_t retval; 754 705 755 /* Retrieve the 3 arguments. The last one is 706 /* Retrieve the 3 arguments. The last one is an array containing the 756 remaining arguments */ 707 remaining arguments */ 757 retval = sos_syscall_get3args(user_ctxt, arg 708 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 758 (unsigned int 709 (unsigned int *)& uaddr_other_args); 759 if (SOS_OK != retval) 710 if (SOS_OK != retval) 760 return retval; 711 return retval; 761 712 762 /* Copy the array containing the remaining a 713 /* Copy the array containing the remaining arguments from user 763 space */ 714 space */ 764 retval = sos_memcpy_from_user((sos_vaddr_t)o 715 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 765 (sos_uaddr_t)u 716 (sos_uaddr_t)uaddr_other_args, 766 sizeof(other_a 717 sizeof(other_args)); 767 if (sizeof(other_args) != retval) 718 if (sizeof(other_args) != retval) 768 return -SOS_EFAULT; 719 return -SOS_EFAULT; 769 720 770 *arg3 = other_args[0]; 721 *arg3 = other_args[0]; 771 *arg4 = other_args[1]; 722 *arg4 = other_args[1]; 772 *arg5 = other_args[2]; 723 *arg5 = other_args[2]; 773 return SOS_OK; 724 return SOS_OK; 774 } 725 } 775 726 776 727 777 sos_ret_t sos_syscall_get6args(const struct so 728 sos_ret_t sos_syscall_get6args(const struct sos_cpu_state *user_ctxt, 778 /* out */unsign 729 /* out */unsigned int *arg1, 779 /* out */unsign 730 /* out */unsigned int *arg2, 780 /* out */unsign 731 /* out */unsigned int *arg3, 781 /* out */unsign 732 /* out */unsigned int *arg4, 782 /* out */unsign 733 /* out */unsigned int *arg5, 783 /* out */unsign 734 /* out */unsigned int *arg6) 784 { 735 { 785 sos_uaddr_t uaddr_other_args; 736 sos_uaddr_t uaddr_other_args; 786 unsigned int other_args[4]; 737 unsigned int other_args[4]; 787 sos_ret_t retval; 738 sos_ret_t retval; 788 739 789 /* Retrieve the 3 arguments. The last one is 740 /* Retrieve the 3 arguments. The last one is an array containing the 790 remaining arguments */ 741 remaining arguments */ 791 retval = sos_syscall_get3args(user_ctxt, arg 742 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 792 (unsigned int 743 (unsigned int *)& uaddr_other_args); 793 if (SOS_OK != retval) 744 if (SOS_OK != retval) 794 return retval; 745 return retval; 795 746 796 /* Copy the array containing the remaining a 747 /* Copy the array containing the remaining arguments from user 797 space */ 748 space */ 798 retval = sos_memcpy_from_user((sos_vaddr_t)o 749 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 799 (sos_uaddr_t)u 750 (sos_uaddr_t)uaddr_other_args, 800 sizeof(other_a 751 sizeof(other_args)); 801 if (sizeof(other_args) != retval) 752 if (sizeof(other_args) != retval) 802 return -SOS_EFAULT; 753 return -SOS_EFAULT; 803 754 804 *arg3 = other_args[0]; 755 *arg3 = other_args[0]; 805 *arg4 = other_args[1]; 756 *arg4 = other_args[1]; 806 *arg5 = other_args[2]; 757 *arg5 = other_args[2]; 807 *arg6 = other_args[3]; 758 *arg6 = other_args[3]; 808 return SOS_OK; 759 return SOS_OK; 809 } 760 } 810 761 811 762 812 sos_ret_t sos_syscall_get7args(const struct so 763 sos_ret_t sos_syscall_get7args(const struct sos_cpu_state *user_ctxt, 813 /* out */unsign 764 /* out */unsigned int *arg1, 814 /* out */unsign 765 /* out */unsigned int *arg2, 815 /* out */unsign 766 /* out */unsigned int *arg3, 816 /* out */unsign 767 /* out */unsigned int *arg4, 817 /* out */unsign 768 /* out */unsigned int *arg5, 818 /* out */unsign 769 /* out */unsigned int *arg6, 819 /* out */unsign 770 /* out */unsigned int *arg7) 820 { 771 { 821 sos_uaddr_t uaddr_other_args; 772 sos_uaddr_t uaddr_other_args; 822 unsigned int other_args[5]; 773 unsigned int other_args[5]; 823 sos_ret_t retval; 774 sos_ret_t retval; 824 775 825 /* Retrieve the 3 arguments. The last one is 776 /* Retrieve the 3 arguments. The last one is an array containing the 826 remaining arguments */ 777 remaining arguments */ 827 retval = sos_syscall_get3args(user_ctxt, arg 778 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 828 (unsigned int 779 (unsigned int *)& uaddr_other_args); 829 if (SOS_OK != retval) 780 if (SOS_OK != retval) 830 return retval; 781 return retval; 831 782 832 /* Copy the array containing the remaining a 783 /* Copy the array containing the remaining arguments from user 833 space */ 784 space */ 834 retval = sos_memcpy_from_user((sos_vaddr_t)o 785 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 835 (sos_uaddr_t)u 786 (sos_uaddr_t)uaddr_other_args, 836 sizeof(other_a 787 sizeof(other_args)); 837 if (sizeof(other_args) != retval) 788 if (sizeof(other_args) != retval) 838 return -SOS_EFAULT; 789 return -SOS_EFAULT; 839 790 840 *arg3 = other_args[0]; 791 *arg3 = other_args[0]; 841 *arg4 = other_args[1]; 792 *arg4 = other_args[1]; 842 *arg5 = other_args[2]; 793 *arg5 = other_args[2]; 843 *arg6 = other_args[3]; 794 *arg6 = other_args[3]; 844 *arg7 = other_args[4]; 795 *arg7 = other_args[4]; 845 return SOS_OK; 796 return SOS_OK; 846 } 797 } 847 798 848 799 849 sos_ret_t sos_syscall_get8args(const struct so 800 sos_ret_t sos_syscall_get8args(const struct sos_cpu_state *user_ctxt, 850 /* out */unsign 801 /* out */unsigned int *arg1, 851 /* out */unsign 802 /* out */unsigned int *arg2, 852 /* out */unsign 803 /* out */unsigned int *arg3, 853 /* out */unsign 804 /* out */unsigned int *arg4, 854 /* out */unsign 805 /* out */unsigned int *arg5, 855 /* out */unsign 806 /* out */unsigned int *arg6, 856 /* out */unsign 807 /* out */unsigned int *arg7, 857 /* out */unsign 808 /* out */unsigned int *arg8) 858 { 809 { 859 sos_uaddr_t uaddr_other_args; 810 sos_uaddr_t uaddr_other_args; 860 unsigned int other_args[6]; 811 unsigned int other_args[6]; 861 sos_ret_t retval; 812 sos_ret_t retval; 862 813 863 /* Retrieve the 3 arguments. The last one is 814 /* Retrieve the 3 arguments. The last one is an array containing the 864 remaining arguments */ 815 remaining arguments */ 865 retval = sos_syscall_get3args(user_ctxt, arg 816 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 866 (unsigned int 817 (unsigned int *)& uaddr_other_args); 867 if (SOS_OK != retval) 818 if (SOS_OK != retval) 868 return retval; 819 return retval; 869 820 870 /* Copy the array containing the remaining a 821 /* Copy the array containing the remaining arguments from user 871 space */ 822 space */ 872 retval = sos_memcpy_from_user((sos_vaddr_t)o 823 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 873 (sos_uaddr_t)u 824 (sos_uaddr_t)uaddr_other_args, 874 sizeof(other_a 825 sizeof(other_args)); 875 if (sizeof(other_args) != retval) 826 if (sizeof(other_args) != retval) 876 return -SOS_EFAULT; 827 return -SOS_EFAULT; 877 828 878 *arg3 = other_args[0]; 829 *arg3 = other_args[0]; 879 *arg4 = other_args[1]; 830 *arg4 = other_args[1]; 880 *arg5 = other_args[2]; 831 *arg5 = other_args[2]; 881 *arg6 = other_args[3]; 832 *arg6 = other_args[3]; 882 *arg7 = other_args[4]; 833 *arg7 = other_args[4]; 883 *arg8 = other_args[5]; 834 *arg8 = other_args[5]; 884 return SOS_OK; 835 return SOS_OK; 885 } 836 } 886 837 887 838 888 /* =========================================== 839 /* ======================================================================= 889 * Backtrace facility. To be used for DEBUGgin 840 * Backtrace facility. To be used for DEBUGging purpose ONLY. 890 */ 841 */ 891 842 892 843 893 sos_ui32_t sos_backtrace(const struct sos_cpu_ 844 sos_ui32_t sos_backtrace(const struct sos_cpu_state *cpu_state, 894 sos_ui32_t max_depth, 845 sos_ui32_t max_depth, 895 sos_vaddr_t stack_bot 846 sos_vaddr_t stack_bottom, 896 sos_size_t stack_size 847 sos_size_t stack_size, 897 sos_backtrace_callbac 848 sos_backtrace_callback_t * backtracer, 898 void *custom_arg) 849 void *custom_arg) 899 { 850 { 900 int depth; 851 int depth; 901 sos_vaddr_t callee_PC, caller_frame; 852 sos_vaddr_t callee_PC, caller_frame; 902 853 903 /* Cannot backtrace an interrupted user thre 854 /* Cannot backtrace an interrupted user thread ! */ 904 if ((NULL != cpu_state) 855 if ((NULL != cpu_state) 905 && 856 && 906 (TRUE == sos_cpu_context_is_in_user_mode 857 (TRUE == sos_cpu_context_is_in_user_mode(cpu_state))) 907 { 858 { 908 return 0; 859 return 0; 909 } 860 } 910 861 911 /* 862 /* 912 * Layout of a frame on the x86 (compiler=gc 863 * Layout of a frame on the x86 (compiler=gcc): 913 * 864 * 914 * funcA calls funcB calls funcC 865 * funcA calls funcB calls funcC 915 * 866 * 916 * .... 867 * .... 917 * funcB Argument 2 868 * funcB Argument 2 918 * funcB Argument 1 869 * funcB Argument 1 919 * funcA Return eip 870 * funcA Return eip 920 * frameB: funcA ebp (ie previous stack fram 871 * frameB: funcA ebp (ie previous stack frame) 921 * .... 872 * .... 922 * (funcB local variables) 873 * (funcB local variables) 923 * .... 874 * .... 924 * funcC Argument 2 875 * funcC Argument 2 925 * funcC Argument 1 876 * funcC Argument 1 926 * funcB Return eip 877 * funcB Return eip 927 * frameC: funcB ebp (ie previous stack fram 878 * frameC: funcB ebp (ie previous stack frame == A0) <---- a frame address 928 * .... 879 * .... 929 * (funcC local variables) 880 * (funcC local variables) 930 * .... 881 * .... 931 * 882 * 932 * The presence of "ebp" on the stack depend 883 * The presence of "ebp" on the stack depends on 2 things: 933 * + the compiler is gcc 884 * + the compiler is gcc 934 * + the source is compiled WITHOUT the -f 885 * + the source is compiled WITHOUT the -fomit-frame-pointer option 935 * In the absence of "ebp", chances are high 886 * In the absence of "ebp", chances are high that the value pushed 936 * at that address is outside the stack boun 887 * at that address is outside the stack boundaries, meaning that the 937 * function will return -SOS_ENOSUP. 888 * function will return -SOS_ENOSUP. 938 */ 889 */ 939 890 940 if (cpu_state) 891 if (cpu_state) 941 { 892 { 942 callee_PC = cpu_state->eip; 893 callee_PC = cpu_state->eip; 943 caller_frame = cpu_state->ebp; 894 caller_frame = cpu_state->ebp; 944 } 895 } 945 else 896 else 946 { 897 { 947 /* Skip the sos_backtrace() frame */ 898 /* Skip the sos_backtrace() frame */ 948 callee_PC = (sos_vaddr_t)__builtin_re 899 callee_PC = (sos_vaddr_t)__builtin_return_address(0); 949 caller_frame = (sos_vaddr_t)__builtin_fr 900 caller_frame = (sos_vaddr_t)__builtin_frame_address(1); 950 } 901 } 951 902 952 for(depth=0 ; depth < max_depth ; depth ++) 903 for(depth=0 ; depth < max_depth ; depth ++) 953 { 904 { 954 /* Call the callback */ 905 /* Call the callback */ 955 backtracer(callee_PC, caller_frame + 8, 906 backtracer(callee_PC, caller_frame + 8, depth, custom_arg); 956 907 957 /* If the frame address is funky, don't 908 /* If the frame address is funky, don't go further */ 958 if ( (caller_frame < stack_bottom) 909 if ( (caller_frame < stack_bottom) 959 || (caller_frame + 4 >= stack_botto 910 || (caller_frame + 4 >= stack_bottom + stack_size) ) 960 return depth; 911 return depth; 961 912 962 /* Go to caller frame */ 913 /* Go to caller frame */ 963 callee_PC = *((sos_vaddr_t*) (caller_ 914 callee_PC = *((sos_vaddr_t*) (caller_frame + 4)); 964 caller_frame = *((sos_vaddr_t*) caller_f 915 caller_frame = *((sos_vaddr_t*) caller_frame); 965 } 916 } 966 917 967 return depth; 918 return depth; 968 } 919 } 969 920 970 921 971 /* ******************************************* 922 /* ************************************************************* 972 * Function to manage the TSS. This function 923 * Function to manage the TSS. This function is not really "public": 973 * it is reserved to the assembler routines de 924 * it is reserved to the assembler routines defined in 974 * cpu_context_switch.S 925 * cpu_context_switch.S 975 * 926 * 976 * Update the kernel stack address so that the 927 * Update the kernel stack address so that the IRQ, syscalls and 977 * exception return in a correct stack locatio 928 * exception return in a correct stack location when coming back into 978 * kernel mode. 929 * kernel mode. 979 */ 930 */ 980 void 931 void 981 sos_cpu_context_update_kernel_tss(struct sos_c 932 sos_cpu_context_update_kernel_tss(struct sos_cpu_state *next_ctxt) 982 { 933 { 983 /* next_ctxt corresponds to an interrupted u 934 /* next_ctxt corresponds to an interrupted user thread ? */ 984 if (sos_cpu_context_is_in_user_mode(next_ctx 935 if (sos_cpu_context_is_in_user_mode(next_ctxt)) 985 { 936 { 986 /* 937 /* 987 * Yes: "next_ctxt" is an interrupted us 938 * Yes: "next_ctxt" is an interrupted user thread => we are 988 * going to switch to user mode ! Setup 939 * going to switch to user mode ! Setup the stack address so 989 * that the user thread "next_ctxt" can 940 * that the user thread "next_ctxt" can come back to the correct 990 * stack location when returning in kern 941 * stack location when returning in kernel mode. 991 * 942 * 992 * This stack location corresponds to th 943 * This stack location corresponds to the SP of the next user 993 * thread once its context has been tran 944 * thread once its context has been transferred on the CPU, ie 994 * once the CPU has executed all the pop 945 * once the CPU has executed all the pop/iret instruction of the 995 * context switch with privilege change. 946 * context switch with privilege change. 996 */ 947 */ 997 kernel_tss.esp0 = ((sos_vaddr_t)next_ctx 948 kernel_tss.esp0 = ((sos_vaddr_t)next_ctxt) 998 + sizeof(struct sos_cp 949 + sizeof(struct sos_cpu_ustate); 999 /* Note: no need to protect this agains 950 /* Note: no need to protect this agains IRQ because IRQs are not 1000 allowed to update it by themselves, 951 allowed to update it by themselves, and they are not allowed 1001 to block */ 952 to block */ 1002 } 953 } 1003 else 954 else 1004 { 955 { 1005 /* No: No need to update kernel TSS whe 956 /* No: No need to update kernel TSS when we stay in kernel 1006 mode */ 957 mode */ 1007 } 958 } 1008 } 959 }
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