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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 /** 356 * Helper function to create a new user thread 356 * Helper function to create a new user thread context. When 357 * model_uctxt is NON NULL, the new user conte 357 * model_uctxt is NON NULL, the new user context is the copy of 358 * model_uctxt, otherwise the SP/PC registers 358 * model_uctxt, otherwise the SP/PC registers are initialized to the 359 * user_initial_SP/PC arguments 359 * user_initial_SP/PC arguments 360 */ 360 */ 361 static sos_ret_t cpu_ustate_init(struct sos_cp 361 static sos_ret_t cpu_ustate_init(struct sos_cpu_state **ctxt, 362 const struct 362 const struct sos_cpu_state *model_uctxt, 363 sos_uaddr_t 363 sos_uaddr_t user_start_PC, 364 sos_ui32_t 364 sos_ui32_t user_start_arg1, 365 sos_ui32_t 365 sos_ui32_t user_start_arg2, 366 sos_uaddr_t 366 sos_uaddr_t user_initial_SP, 367 sos_vaddr_t 367 sos_vaddr_t kernel_stack_bottom, 368 sos_size_t 368 sos_size_t kernel_stack_size) 369 { 369 { 370 /* We are initializing a User thread's conte 370 /* We are initializing a User thread's context */ 371 struct sos_cpu_ustate *uctxt; 371 struct sos_cpu_ustate *uctxt; 372 372 373 /* This is a critical internal function, so 373 /* This is a critical internal function, so that it is assumed that 374 the caller knows what he does: we legitim 374 the caller knows what he does: we legitimally assume that values 375 for ctxt, etc. are allways VALID ! */ 375 for ctxt, etc. are allways VALID ! */ 376 376 377 /* Compute the address of the CPU state to r 377 /* Compute the address of the CPU state to restore on CPU when 378 switching to this new user thread */ 378 switching to this new user thread */ 379 sos_vaddr_t uctxt_vaddr = kernel_stack_botto 379 sos_vaddr_t uctxt_vaddr = kernel_stack_bottom 380 + kernel_stack_si 380 + kernel_stack_size 381 - sizeof(struct s 381 - sizeof(struct sos_cpu_ustate); 382 uctxt = (struct sos_cpu_ustate*)uctxt_vaddr; 382 uctxt = (struct sos_cpu_ustate*)uctxt_vaddr; 383 383 384 if (model_uctxt && !sos_cpu_context_is_in_us 384 if (model_uctxt && !sos_cpu_context_is_in_user_mode(model_uctxt)) 385 return -SOS_EINVAL; 385 return -SOS_EINVAL; 386 386 387 /* If needed, poison the kernel stack */ 387 /* If needed, poison the kernel stack */ 388 #ifdef SOS_CPU_STATE_DETECT_UNINIT_KERNEL_VARS 388 #ifdef SOS_CPU_STATE_DETECT_UNINIT_KERNEL_VARS 389 memset((void*)kernel_stack_bottom, 389 memset((void*)kernel_stack_bottom, 390 SOS_CPU_STATE_STACK_POISON, 390 SOS_CPU_STATE_STACK_POISON, 391 kernel_stack_size); 391 kernel_stack_size); 392 #elif defined(SOS_CPU_STATE_DETECT_KERNEL_STAC 392 #elif defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) 393 sos_cpu_state_prepare_detect_kernel_stack_ov 393 sos_cpu_state_prepare_detect_kernel_stack_overflow(kernel_stack_bottom, 394 394 kernel_stack_size); 395 #endif 395 #endif 396 396 397 /* 397 /* 398 * Setup the initial context structure, so t 398 * Setup the initial context structure, so that the CPU will restore 399 * the initial registers' value for the user 399 * the initial registers' value for the user thread. The 400 * user thread argument is passed in the EAX 400 * user thread argument is passed in the EAX register. 401 */ 401 */ 402 402 403 /* Initialize the CPU context structure */ 403 /* Initialize the CPU context structure */ 404 if (! model_uctxt) 404 if (! model_uctxt) 405 { 405 { 406 memset(uctxt, 0x0, sizeof(struct sos_cpu 406 memset(uctxt, 0x0, sizeof(struct sos_cpu_ustate)); 407 407 408 /* Tell the CPU context structure that t 408 /* Tell the CPU context structure that the first instruction to 409 execute will be located at user_start 409 execute will be located at user_start_PC (in user space) */ 410 uctxt->regs.eip = (sos_ui32_t)user_start 410 uctxt->regs.eip = (sos_ui32_t)user_start_PC; 411 411 412 /* Tell the CPU where will be the user s 412 /* Tell the CPU where will be the user stack */ 413 uctxt->cpl3_esp = user_initial_SP; 413 uctxt->cpl3_esp = user_initial_SP; 414 } 414 } 415 else 415 else 416 memcpy(uctxt, model_uctxt, sizeof(struct s 416 memcpy(uctxt, model_uctxt, sizeof(struct sos_cpu_ustate)); 417 417 418 /* The parameter to the start function is no 418 /* The parameter to the start function is not passed by the stack to 419 avoid a possible page fault */ 419 avoid a possible page fault */ 420 uctxt->regs.eax = user_start_arg1; 420 uctxt->regs.eax = user_start_arg1; 421 421 422 /* Optional additional argument for non-dupl 422 /* Optional additional argument for non-duplicated threads */ 423 if (! model_uctxt) 423 if (! model_uctxt) 424 uctxt->regs.ebx = user_start_arg2; 424 uctxt->regs.ebx = user_start_arg2; 425 425 426 /* Setup the segment registers */ 426 /* Setup the segment registers */ 427 uctxt->regs.cs 427 uctxt->regs.cs 428 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 428 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UCODE); /* Code */ 429 uctxt->regs.ds 429 uctxt->regs.ds 430 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 430 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UDATA); /* Data */ 431 uctxt->regs.es 431 uctxt->regs.es 432 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 432 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UDATA); /* Data */ 433 uctxt->cpl3_ss 433 uctxt->cpl3_ss 434 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SO 434 = SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UDATA); /* User Stack */ 435 435 436 /* We need also to update the segment for th 436 /* We need also to update the segment for the kernel stack 437 segment. It will be used when this contex 437 segment. It will be used when this context will be restored on 438 CPU: initially it will be executing in ke 438 CPU: initially it will be executing in kernel mode and will 439 switch immediatly to user mode */ 439 switch immediatly to user mode */ 440 uctxt->regs.cpl0_ss 440 uctxt->regs.cpl0_ss 441 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SO 441 = SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KDATA); /* Kernel Stack */ 442 442 443 /* fs and gs unused for the moment. */ 443 /* fs and gs unused for the moment. */ 444 444 445 /* The newly created context is initially in 445 /* The newly created context is initially interruptible */ 446 uctxt->regs.eflags = (1 << 9); /* set IF bit 446 uctxt->regs.eflags = (1 << 9); /* set IF bit */ 447 447 448 /* Finally, update the generic kernel/user t 448 /* Finally, update the generic kernel/user thread context */ 449 *ctxt = (struct sos_cpu_state*) uctxt; 449 *ctxt = (struct sos_cpu_state*) uctxt; 450 450 451 return SOS_OK; 451 return SOS_OK; 452 } 452 } 453 453 454 454 455 sos_ret_t sos_cpu_ustate_init(struct sos_cpu_s 455 sos_ret_t sos_cpu_ustate_init(struct sos_cpu_state **ctxt, 456 sos_uaddr_t use 456 sos_uaddr_t user_start_PC, 457 sos_ui32_t use 457 sos_ui32_t user_start_arg1, 458 sos_ui32_t use 458 sos_ui32_t user_start_arg2, 459 sos_uaddr_t use 459 sos_uaddr_t user_initial_SP, 460 sos_vaddr_t ker 460 sos_vaddr_t kernel_stack_bottom, 461 sos_size_t ker 461 sos_size_t kernel_stack_size) 462 { 462 { 463 return cpu_ustate_init(ctxt, NULL, 463 return cpu_ustate_init(ctxt, NULL, 464 user_start_PC, 464 user_start_PC, 465 user_start_arg1, user 465 user_start_arg1, user_start_arg2, 466 user_initial_SP, 466 user_initial_SP, 467 kernel_stack_bottom, 467 kernel_stack_bottom, kernel_stack_size); 468 } 468 } 469 469 470 470 471 sos_ret_t sos_cpu_ustate_duplicate(struct sos_ 471 sos_ret_t sos_cpu_ustate_duplicate(struct sos_cpu_state **ctxt, 472 const struc 472 const struct sos_cpu_state *model_uctxt, 473 sos_ui32_t 473 sos_ui32_t user_retval, 474 sos_vaddr_t 474 sos_vaddr_t kernel_stack_bottom, 475 sos_size_t 475 sos_size_t kernel_stack_size) 476 { 476 { 477 return cpu_ustate_init(ctxt, model_uctxt, 477 return cpu_ustate_init(ctxt, model_uctxt, 478 /* ignored */0, 478 /* ignored */0, 479 user_retval, /* ignor 479 user_retval, /* ignored */0, 480 /* ignored */0, 480 /* ignored */0, 481 kernel_stack_bottom, 481 kernel_stack_bottom, kernel_stack_size); 482 } 482 } 483 483 484 484 485 sos_ret_t 485 sos_ret_t 486 sos_cpu_context_is_in_user_mode(const struct s 486 sos_cpu_context_is_in_user_mode(const struct sos_cpu_state *ctxt) 487 { 487 { 488 /* An interrupted user thread has its CS reg 488 /* An interrupted user thread has its CS register set to that of the 489 User code segment */ 489 User code segment */ 490 switch (GET_CPU_CS_REGISTER_VALUE(ctxt->cs)) 490 switch (GET_CPU_CS_REGISTER_VALUE(ctxt->cs)) 491 { 491 { 492 case SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, 492 case SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UCODE): 493 return TRUE; 493 return TRUE; 494 break; 494 break; 495 495 496 case SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, 496 case SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KCODE): 497 return FALSE; 497 return FALSE; 498 break; 498 break; 499 499 500 default: 500 default: 501 SOS_FATAL_ERROR("Invalid saved context C 501 SOS_FATAL_ERROR("Invalid saved context Code segment register: 0x%x (k=%x, u=%x) !", 502 (unsigned) GET_CPU_CS_RE 502 (unsigned) GET_CPU_CS_REGISTER_VALUE(ctxt->cs), 503 SOS_BUILD_SEGMENT_REG_VA 503 SOS_BUILD_SEGMENT_REG_VALUE(0, FALSE, SOS_SEG_KCODE), 504 SOS_BUILD_SEGMENT_REG_VA 504 SOS_BUILD_SEGMENT_REG_VALUE(3, FALSE, SOS_SEG_UCODE)); 505 break; 505 break; 506 } 506 } 507 507 508 /* Should never get here */ 508 /* Should never get here */ 509 return -SOS_EFATAL; 509 return -SOS_EFATAL; 510 } 510 } 511 511 512 512 513 #if defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_ 513 #if defined(SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) 514 void 514 void 515 sos_cpu_state_prepare_detect_kernel_stack_over 515 sos_cpu_state_prepare_detect_kernel_stack_overflow(const struct sos_cpu_state *ctxt, 516 516 sos_vaddr_t stack_bottom, 517 517 sos_size_t stack_size) 518 { 518 { 519 sos_size_t poison_size = SOS_CPU_STATE_DETEC 519 sos_size_t poison_size = SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW; 520 if (poison_size > stack_size) 520 if (poison_size > stack_size) 521 poison_size = stack_size; 521 poison_size = stack_size; 522 522 523 memset((void*)stack_bottom, SOS_CPU_STATE_ST 523 memset((void*)stack_bottom, SOS_CPU_STATE_STACK_POISON, poison_size); 524 } 524 } 525 525 526 526 527 void 527 void 528 sos_cpu_state_detect_kernel_stack_overflow(con 528 sos_cpu_state_detect_kernel_stack_overflow(const struct sos_cpu_state *ctxt, 529 sos 529 sos_vaddr_t stack_bottom, 530 sos 530 sos_size_t stack_size) 531 { 531 { 532 unsigned char *c; 532 unsigned char *c; 533 int i; 533 int i; 534 534 535 /* On SOS, "ctxt" corresponds to the address 535 /* On SOS, "ctxt" corresponds to the address of the esp register of 536 the saved context in Kernel mode (always, 536 the saved context in Kernel mode (always, even for the interrupted 537 context of a user thread). Here we make s 537 context of a user thread). Here we make sure that this stack 538 pointer is within the allowed stack area 538 pointer is within the allowed stack area */ 539 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) >= stac 539 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) >= stack_bottom); 540 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) + sizeo 540 SOS_ASSERT_FATAL(((sos_vaddr_t)ctxt) + sizeof(struct sos_cpu_kstate) 541 <= stack_bottom + stack_siz 541 <= stack_bottom + stack_size); 542 542 543 /* Check that the bottom of the stack has no 543 /* Check that the bottom of the stack has not been altered */ 544 for (c = (unsigned char*) stack_bottom, i = 544 for (c = (unsigned char*) stack_bottom, i = 0 ; 545 (i < SOS_CPU_STATE_DETECT_KERNEL_STACK_ 545 (i < SOS_CPU_STATE_DETECT_KERNEL_STACK_OVERFLOW) && (i < stack_size) ; 546 c++, i++) 546 c++, i++) 547 { 547 { 548 SOS_ASSERT_FATAL(SOS_CPU_STATE_STACK_POI 548 SOS_ASSERT_FATAL(SOS_CPU_STATE_STACK_POISON == *c); 549 } 549 } 550 } 550 } 551 #endif 551 #endif 552 552 553 553 554 /* =========================================== 554 /* ======================================================================= 555 * Public Accessor functions 555 * Public Accessor functions 556 */ 556 */ 557 557 558 558 559 sos_vaddr_t sos_cpu_context_get_PC(const struc 559 sos_vaddr_t sos_cpu_context_get_PC(const struct sos_cpu_state *ctxt) 560 { 560 { 561 SOS_ASSERT_FATAL(NULL != ctxt); 561 SOS_ASSERT_FATAL(NULL != ctxt); 562 562 563 /* This is the PC of the interrupted context 563 /* This is the PC of the interrupted context (ie kernel or user 564 context). */ 564 context). */ 565 return ctxt->eip; 565 return ctxt->eip; 566 } 566 } 567 567 568 568 569 sos_vaddr_t sos_cpu_context_get_SP(const struc 569 sos_vaddr_t sos_cpu_context_get_SP(const struct sos_cpu_state *ctxt) 570 { 570 { 571 SOS_ASSERT_FATAL(NULL != ctxt); 571 SOS_ASSERT_FATAL(NULL != ctxt); 572 572 573 /* 'ctxt' corresponds to the SP of the inter 573 /* 'ctxt' corresponds to the SP of the interrupted context, in Kernel 574 mode. We have to test whether the origina 574 mode. We have to test whether the original interrupted context 575 was that of a kernel or user thread */ 575 was that of a kernel or user thread */ 576 if (TRUE == sos_cpu_context_is_in_user_mode( 576 if (TRUE == sos_cpu_context_is_in_user_mode(ctxt)) 577 { 577 { 578 struct sos_cpu_ustate * uctxt = (struct 578 struct sos_cpu_ustate * uctxt = (struct sos_cpu_ustate*)ctxt; 579 return uctxt->cpl3_esp; 579 return uctxt->cpl3_esp; 580 } 580 } 581 581 582 /* On SOS, "ctxt" corresponds to the address 582 /* On SOS, "ctxt" corresponds to the address of the esp register of 583 the saved context in Kernel mode (always, 583 the saved context in Kernel mode (always, even for the interrupted 584 context of a user thread). */ 584 context of a user thread). */ 585 return (sos_vaddr_t)ctxt; 585 return (sos_vaddr_t)ctxt; 586 } 586 } 587 587 588 588 589 sos_ret_t 589 sos_ret_t 590 sos_cpu_context_set_EX_return_address(struct s 590 sos_cpu_context_set_EX_return_address(struct sos_cpu_state *ctxt, 591 sos_vadd 591 sos_vaddr_t ret_vaddr) 592 { 592 { 593 ctxt->eip = ret_vaddr; 593 ctxt->eip = ret_vaddr; 594 return SOS_OK; 594 return SOS_OK; 595 } 595 } 596 596 597 597 598 void sos_cpu_context_dump(const struct sos_cpu 598 void sos_cpu_context_dump(const struct sos_cpu_state *ctxt) 599 { 599 { 600 char buf[128]; 600 char buf[128]; 601 601 602 snprintf(buf, sizeof(buf), 602 snprintf(buf, sizeof(buf), 603 "CPU: eip=%x esp0=%x eflags=%x cs=% 603 "CPU: eip=%x esp0=%x eflags=%x cs=%x ds=%x ss0=%x err=%x", 604 (unsigned)ctxt->eip, (unsigned)ctxt 604 (unsigned)ctxt->eip, (unsigned)ctxt, (unsigned)ctxt->eflags, 605 (unsigned)GET_CPU_CS_REGISTER_VALUE 605 (unsigned)GET_CPU_CS_REGISTER_VALUE(ctxt->cs), (unsigned)ctxt->ds, 606 (unsigned)ctxt->cpl0_ss, 606 (unsigned)ctxt->cpl0_ss, 607 (unsigned)ctxt->error_code); 607 (unsigned)ctxt->error_code); 608 if (TRUE == sos_cpu_context_is_in_user_mode( 608 if (TRUE == sos_cpu_context_is_in_user_mode(ctxt)) 609 { 609 { 610 struct sos_cpu_ustate * uctxt = (struct 610 struct sos_cpu_ustate * uctxt = (struct sos_cpu_ustate*)ctxt; 611 snprintf(buf, sizeof(buf), 611 snprintf(buf, sizeof(buf), 612 "%s esp3=%x ss3=%x", 612 "%s esp3=%x ss3=%x", 613 buf, (unsigned)uctxt->cpl3_esp, 613 buf, (unsigned)uctxt->cpl3_esp, (unsigned)uctxt->cpl3_ss); 614 } 614 } 615 else 615 else 616 snprintf(buf, sizeof(buf), "%s [KERNEL MOD 616 snprintf(buf, sizeof(buf), "%s [KERNEL MODE]", buf); 617 617 618 sos_bochs_putstring(buf); sos_bochs_putstrin 618 sos_bochs_putstring(buf); sos_bochs_putstring("\n"); 619 sos_x86_videomem_putstring(23, 0, 619 sos_x86_videomem_putstring(23, 0, 620 SOS_X86_VIDEO_FG_ 620 SOS_X86_VIDEO_FG_BLACK | SOS_X86_VIDEO_BG_LTGRAY, 621 buf); 621 buf); 622 } 622 } 623 623 624 624 625 /* =========================================== 625 /* ======================================================================= 626 * Public Accessor functions TO BE USED ONLY B 626 * Public Accessor functions TO BE USED ONLY BY Exception handlers 627 */ 627 */ 628 628 629 629 630 sos_ui32_t sos_cpu_context_get_EX_info(const s 630 sos_ui32_t sos_cpu_context_get_EX_info(const struct sos_cpu_state *ctxt) 631 { 631 { 632 SOS_ASSERT_FATAL(NULL != ctxt); 632 SOS_ASSERT_FATAL(NULL != ctxt); 633 return ctxt->error_code; 633 return ctxt->error_code; 634 } 634 } 635 635 636 636 637 sos_vaddr_t 637 sos_vaddr_t 638 sos_cpu_context_get_EX_faulting_vaddr(const st 638 sos_cpu_context_get_EX_faulting_vaddr(const struct sos_cpu_state *ctxt) 639 { 639 { 640 sos_ui32_t cr2; 640 sos_ui32_t cr2; 641 641 642 /* 642 /* 643 * See Intel Vol 3 (section 5.14): the addre 643 * See Intel Vol 3 (section 5.14): the address of the faulting 644 * virtual address of a page fault is stored 644 * virtual address of a page fault is stored in the cr2 645 * register. 645 * register. 646 * 646 * 647 * Actually, we do not store the cr2 registe 647 * Actually, we do not store the cr2 register in a saved 648 * kernel thread's context. So we retrieve t 648 * kernel thread's context. So we retrieve the cr2's value directly 649 * from the processor. The value we retrieve 649 * from the processor. The value we retrieve in an exception handler 650 * is actually the correct one because an ex 650 * is actually the correct one because an exception is synchronous 651 * with the code causing the fault, and cann 651 * with the code causing the fault, and cannot be interrupted since 652 * the IDT entries in SOS are "interrupt gat 652 * the IDT entries in SOS are "interrupt gates" (ie IRQ are 653 * disabled). 653 * disabled). 654 */ 654 */ 655 asm volatile ("movl %%cr2, %0" 655 asm volatile ("movl %%cr2, %0" 656 :"=r"(cr2) 656 :"=r"(cr2) 657 : ); 657 : ); 658 658 659 return cr2; 659 return cr2; 660 } 660 } 661 661 662 662 663 /* =========================================== 663 /* ======================================================================= 664 * Public Accessor functions TO BE USED ONLY B 664 * Public Accessor functions TO BE USED ONLY BY the SYSCALL handler 665 */ 665 */ 666 666 667 667 668 /* 668 /* 669 * By convention, the USER SOS programs always 669 * By convention, the USER SOS programs always pass 4 arguments to the 670 * kernel syscall handler: in eax/../edx. For 670 * kernel syscall handler: in eax/../edx. For less arguments, the 671 * unused registers are filled with 0s. For mo 671 * unused registers are filled with 0s. For more arguments, the 4th 672 * syscall parameter gives the address of the 672 * syscall parameter gives the address of the array containing the 673 * remaining arguments. In any case, eax corre 673 * remaining arguments. In any case, eax corresponds to the syscall 674 * IDentifier. 674 * IDentifier. 675 */ 675 */ 676 676 677 677 678 inline 678 inline 679 sos_ret_t sos_syscall_get3args(const struct so 679 sos_ret_t sos_syscall_get3args(const struct sos_cpu_state *user_ctxt, 680 /* out */unsign 680 /* out */unsigned int *arg1, 681 /* out */unsign 681 /* out */unsigned int *arg2, 682 /* out */unsign 682 /* out */unsigned int *arg3) 683 { 683 { 684 *arg1 = user_ctxt->ebx; 684 *arg1 = user_ctxt->ebx; 685 *arg2 = user_ctxt->ecx; 685 *arg2 = user_ctxt->ecx; 686 *arg3 = user_ctxt->edx; 686 *arg3 = user_ctxt->edx; 687 return SOS_OK; 687 return SOS_OK; 688 } 688 } 689 689 690 690 691 sos_ret_t sos_syscall_get1arg(const struct sos 691 sos_ret_t sos_syscall_get1arg(const struct sos_cpu_state *user_ctxt, 692 /* out */unsigne 692 /* out */unsigned int *arg1) 693 { 693 { 694 unsigned int unused; 694 unsigned int unused; 695 return sos_syscall_get3args(user_ctxt, arg1, 695 return sos_syscall_get3args(user_ctxt, arg1, & unused, & unused); 696 } 696 } 697 697 698 698 699 sos_ret_t sos_syscall_get2args(const struct so 699 sos_ret_t sos_syscall_get2args(const struct sos_cpu_state *user_ctxt, 700 /* out */unsign 700 /* out */unsigned int *arg1, 701 /* out */unsign 701 /* out */unsigned int *arg2) 702 { 702 { 703 unsigned int unused; 703 unsigned int unused; 704 return sos_syscall_get3args(user_ctxt, arg1, 704 return sos_syscall_get3args(user_ctxt, arg1, arg2, & unused); 705 } 705 } 706 706 707 707 708 /* 708 /* 709 * sos_syscall_get3args() is defined in cpu_co 709 * sos_syscall_get3args() is defined in cpu_context.c because it needs 710 * to know the structure of a struct spu_state 710 * to know the structure of a struct spu_state 711 */ 711 */ 712 712 713 sos_ret_t sos_syscall_get4args(const struct so 713 sos_ret_t sos_syscall_get4args(const struct sos_cpu_state *user_ctxt, 714 /* out */unsign 714 /* out */unsigned int *arg1, 715 /* out */unsign 715 /* out */unsigned int *arg2, 716 /* out */unsign 716 /* out */unsigned int *arg3, 717 /* out */unsign 717 /* out */unsigned int *arg4) 718 { 718 { 719 sos_uaddr_t uaddr_other_args; 719 sos_uaddr_t uaddr_other_args; 720 unsigned int other_args[2]; 720 unsigned int other_args[2]; 721 sos_ret_t retval; 721 sos_ret_t retval; 722 722 723 /* Retrieve the 3 arguments. The last one is 723 /* Retrieve the 3 arguments. The last one is an array containing the 724 remaining arguments */ 724 remaining arguments */ 725 retval = sos_syscall_get3args(user_ctxt, arg 725 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 726 (unsigned int 726 (unsigned int *)& uaddr_other_args); 727 if (SOS_OK != retval) 727 if (SOS_OK != retval) 728 return retval; 728 return retval; 729 729 730 /* Copy the array containing the remaining a 730 /* Copy the array containing the remaining arguments from user 731 space */ 731 space */ 732 retval = sos_memcpy_from_user((sos_vaddr_t)o 732 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 733 (sos_uaddr_t)u 733 (sos_uaddr_t)uaddr_other_args, 734 sizeof(other_a 734 sizeof(other_args)); 735 if (sizeof(other_args) != retval) 735 if (sizeof(other_args) != retval) 736 return -SOS_EFAULT; 736 return -SOS_EFAULT; 737 737 738 *arg3 = other_args[0]; 738 *arg3 = other_args[0]; 739 *arg4 = other_args[1]; 739 *arg4 = other_args[1]; 740 return SOS_OK; 740 return SOS_OK; 741 } 741 } 742 742 743 743 744 sos_ret_t sos_syscall_get5args(const struct so 744 sos_ret_t sos_syscall_get5args(const struct sos_cpu_state *user_ctxt, 745 /* out */unsign 745 /* out */unsigned int *arg1, 746 /* out */unsign 746 /* out */unsigned int *arg2, 747 /* out */unsign 747 /* out */unsigned int *arg3, 748 /* out */unsign 748 /* out */unsigned int *arg4, 749 /* out */unsign 749 /* out */unsigned int *arg5) 750 { 750 { 751 sos_uaddr_t uaddr_other_args; 751 sos_uaddr_t uaddr_other_args; 752 unsigned int other_args[3]; 752 unsigned int other_args[3]; 753 sos_ret_t retval; 753 sos_ret_t retval; 754 754 755 /* Retrieve the 3 arguments. The last one is 755 /* Retrieve the 3 arguments. The last one is an array containing the 756 remaining arguments */ 756 remaining arguments */ 757 retval = sos_syscall_get3args(user_ctxt, arg 757 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 758 (unsigned int 758 (unsigned int *)& uaddr_other_args); 759 if (SOS_OK != retval) 759 if (SOS_OK != retval) 760 return retval; 760 return retval; 761 761 762 /* Copy the array containing the remaining a 762 /* Copy the array containing the remaining arguments from user 763 space */ 763 space */ 764 retval = sos_memcpy_from_user((sos_vaddr_t)o 764 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 765 (sos_uaddr_t)u 765 (sos_uaddr_t)uaddr_other_args, 766 sizeof(other_a 766 sizeof(other_args)); 767 if (sizeof(other_args) != retval) 767 if (sizeof(other_args) != retval) 768 return -SOS_EFAULT; 768 return -SOS_EFAULT; 769 769 770 *arg3 = other_args[0]; 770 *arg3 = other_args[0]; 771 *arg4 = other_args[1]; 771 *arg4 = other_args[1]; 772 *arg5 = other_args[2]; 772 *arg5 = other_args[2]; 773 return SOS_OK; 773 return SOS_OK; 774 } 774 } 775 775 776 776 777 sos_ret_t sos_syscall_get6args(const struct so 777 sos_ret_t sos_syscall_get6args(const struct sos_cpu_state *user_ctxt, 778 /* out */unsign 778 /* out */unsigned int *arg1, 779 /* out */unsign 779 /* out */unsigned int *arg2, 780 /* out */unsign 780 /* out */unsigned int *arg3, 781 /* out */unsign 781 /* out */unsigned int *arg4, 782 /* out */unsign 782 /* out */unsigned int *arg5, 783 /* out */unsign 783 /* out */unsigned int *arg6) 784 { 784 { 785 sos_uaddr_t uaddr_other_args; 785 sos_uaddr_t uaddr_other_args; 786 unsigned int other_args[4]; 786 unsigned int other_args[4]; 787 sos_ret_t retval; 787 sos_ret_t retval; 788 788 789 /* Retrieve the 3 arguments. The last one is 789 /* Retrieve the 3 arguments. The last one is an array containing the 790 remaining arguments */ 790 remaining arguments */ 791 retval = sos_syscall_get3args(user_ctxt, arg 791 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 792 (unsigned int 792 (unsigned int *)& uaddr_other_args); 793 if (SOS_OK != retval) 793 if (SOS_OK != retval) 794 return retval; 794 return retval; 795 795 796 /* Copy the array containing the remaining a 796 /* Copy the array containing the remaining arguments from user 797 space */ 797 space */ 798 retval = sos_memcpy_from_user((sos_vaddr_t)o 798 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 799 (sos_uaddr_t)u 799 (sos_uaddr_t)uaddr_other_args, 800 sizeof(other_a 800 sizeof(other_args)); 801 if (sizeof(other_args) != retval) 801 if (sizeof(other_args) != retval) 802 return -SOS_EFAULT; 802 return -SOS_EFAULT; 803 803 804 *arg3 = other_args[0]; 804 *arg3 = other_args[0]; 805 *arg4 = other_args[1]; 805 *arg4 = other_args[1]; 806 *arg5 = other_args[2]; 806 *arg5 = other_args[2]; 807 *arg6 = other_args[3]; 807 *arg6 = other_args[3]; 808 return SOS_OK; 808 return SOS_OK; 809 } 809 } 810 810 811 811 812 sos_ret_t sos_syscall_get7args(const struct so 812 sos_ret_t sos_syscall_get7args(const struct sos_cpu_state *user_ctxt, 813 /* out */unsign 813 /* out */unsigned int *arg1, 814 /* out */unsign 814 /* out */unsigned int *arg2, 815 /* out */unsign 815 /* out */unsigned int *arg3, 816 /* out */unsign 816 /* out */unsigned int *arg4, 817 /* out */unsign 817 /* out */unsigned int *arg5, 818 /* out */unsign 818 /* out */unsigned int *arg6, 819 /* out */unsign 819 /* out */unsigned int *arg7) 820 { 820 { 821 sos_uaddr_t uaddr_other_args; 821 sos_uaddr_t uaddr_other_args; 822 unsigned int other_args[5]; 822 unsigned int other_args[5]; 823 sos_ret_t retval; 823 sos_ret_t retval; 824 824 825 /* Retrieve the 3 arguments. The last one is 825 /* Retrieve the 3 arguments. The last one is an array containing the 826 remaining arguments */ 826 remaining arguments */ 827 retval = sos_syscall_get3args(user_ctxt, arg 827 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 828 (unsigned int 828 (unsigned int *)& uaddr_other_args); 829 if (SOS_OK != retval) 829 if (SOS_OK != retval) 830 return retval; 830 return retval; 831 831 832 /* Copy the array containing the remaining a 832 /* Copy the array containing the remaining arguments from user 833 space */ 833 space */ 834 retval = sos_memcpy_from_user((sos_vaddr_t)o 834 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 835 (sos_uaddr_t)u 835 (sos_uaddr_t)uaddr_other_args, 836 sizeof(other_a 836 sizeof(other_args)); 837 if (sizeof(other_args) != retval) 837 if (sizeof(other_args) != retval) 838 return -SOS_EFAULT; 838 return -SOS_EFAULT; 839 839 840 *arg3 = other_args[0]; 840 *arg3 = other_args[0]; 841 *arg4 = other_args[1]; 841 *arg4 = other_args[1]; 842 *arg5 = other_args[2]; 842 *arg5 = other_args[2]; 843 *arg6 = other_args[3]; 843 *arg6 = other_args[3]; 844 *arg7 = other_args[4]; 844 *arg7 = other_args[4]; 845 return SOS_OK; 845 return SOS_OK; 846 } 846 } 847 847 848 848 849 sos_ret_t sos_syscall_get8args(const struct so 849 sos_ret_t sos_syscall_get8args(const struct sos_cpu_state *user_ctxt, 850 /* out */unsign 850 /* out */unsigned int *arg1, 851 /* out */unsign 851 /* out */unsigned int *arg2, 852 /* out */unsign 852 /* out */unsigned int *arg3, 853 /* out */unsign 853 /* out */unsigned int *arg4, 854 /* out */unsign 854 /* out */unsigned int *arg5, 855 /* out */unsign 855 /* out */unsigned int *arg6, 856 /* out */unsign 856 /* out */unsigned int *arg7, 857 /* out */unsign 857 /* out */unsigned int *arg8) 858 { 858 { 859 sos_uaddr_t uaddr_other_args; 859 sos_uaddr_t uaddr_other_args; 860 unsigned int other_args[6]; 860 unsigned int other_args[6]; 861 sos_ret_t retval; 861 sos_ret_t retval; 862 862 863 /* Retrieve the 3 arguments. The last one is 863 /* Retrieve the 3 arguments. The last one is an array containing the 864 remaining arguments */ 864 remaining arguments */ 865 retval = sos_syscall_get3args(user_ctxt, arg 865 retval = sos_syscall_get3args(user_ctxt, arg1, arg2, 866 (unsigned int 866 (unsigned int *)& uaddr_other_args); 867 if (SOS_OK != retval) 867 if (SOS_OK != retval) 868 return retval; 868 return retval; 869 869 870 /* Copy the array containing the remaining a 870 /* Copy the array containing the remaining arguments from user 871 space */ 871 space */ 872 retval = sos_memcpy_from_user((sos_vaddr_t)o 872 retval = sos_memcpy_from_user((sos_vaddr_t)other_args, 873 (sos_uaddr_t)u 873 (sos_uaddr_t)uaddr_other_args, 874 sizeof(other_a 874 sizeof(other_args)); 875 if (sizeof(other_args) != retval) 875 if (sizeof(other_args) != retval) 876 return -SOS_EFAULT; 876 return -SOS_EFAULT; 877 877 878 *arg3 = other_args[0]; 878 *arg3 = other_args[0]; 879 *arg4 = other_args[1]; 879 *arg4 = other_args[1]; 880 *arg5 = other_args[2]; 880 *arg5 = other_args[2]; 881 *arg6 = other_args[3]; 881 *arg6 = other_args[3]; 882 *arg7 = other_args[4]; 882 *arg7 = other_args[4]; 883 *arg8 = other_args[5]; 883 *arg8 = other_args[5]; 884 return SOS_OK; 884 return SOS_OK; 885 } 885 } 886 886 887 887 888 /* =========================================== 888 /* ======================================================================= 889 * Backtrace facility. To be used for DEBUGgin 889 * Backtrace facility. To be used for DEBUGging purpose ONLY. 890 */ 890 */ 891 891 892 892 893 sos_ui32_t sos_backtrace(const struct sos_cpu_ 893 sos_ui32_t sos_backtrace(const struct sos_cpu_state *cpu_state, 894 sos_ui32_t max_depth, 894 sos_ui32_t max_depth, 895 sos_vaddr_t stack_bot 895 sos_vaddr_t stack_bottom, 896 sos_size_t stack_size 896 sos_size_t stack_size, 897 sos_backtrace_callbac 897 sos_backtrace_callback_t * backtracer, 898 void *custom_arg) 898 void *custom_arg) 899 { 899 { 900 int depth; 900 int depth; 901 sos_vaddr_t callee_PC, caller_frame; 901 sos_vaddr_t callee_PC, caller_frame; 902 902 903 /* Cannot backtrace an interrupted user thre 903 /* Cannot backtrace an interrupted user thread ! */ 904 if ((NULL != cpu_state) 904 if ((NULL != cpu_state) 905 && 905 && 906 (TRUE == sos_cpu_context_is_in_user_mode 906 (TRUE == sos_cpu_context_is_in_user_mode(cpu_state))) 907 { 907 { 908 return 0; 908 return 0; 909 } 909 } 910 910 911 /* 911 /* 912 * Layout of a frame on the x86 (compiler=gc 912 * Layout of a frame on the x86 (compiler=gcc): 913 * 913 * 914 * funcA calls funcB calls funcC 914 * funcA calls funcB calls funcC 915 * 915 * 916 * .... 916 * .... 917 * funcB Argument 2 917 * funcB Argument 2 918 * funcB Argument 1 918 * funcB Argument 1 919 * funcA Return eip 919 * funcA Return eip 920 * frameB: funcA ebp (ie previous stack fram 920 * frameB: funcA ebp (ie previous stack frame) 921 * .... 921 * .... 922 * (funcB local variables) 922 * (funcB local variables) 923 * .... 923 * .... 924 * funcC Argument 2 924 * funcC Argument 2 925 * funcC Argument 1 925 * funcC Argument 1 926 * funcB Return eip 926 * funcB Return eip 927 * frameC: funcB ebp (ie previous stack fram 927 * frameC: funcB ebp (ie previous stack frame == A0) <---- a frame address 928 * .... 928 * .... 929 * (funcC local variables) 929 * (funcC local variables) 930 * .... 930 * .... 931 * 931 * 932 * The presence of "ebp" on the stack depend 932 * The presence of "ebp" on the stack depends on 2 things: 933 * + the compiler is gcc 933 * + the compiler is gcc 934 * + the source is compiled WITHOUT the -f 934 * + the source is compiled WITHOUT the -fomit-frame-pointer option 935 * In the absence of "ebp", chances are high 935 * In the absence of "ebp", chances are high that the value pushed 936 * at that address is outside the stack boun 936 * at that address is outside the stack boundaries, meaning that the 937 * function will return -SOS_ENOSUP. 937 * function will return -SOS_ENOSUP. 938 */ 938 */ 939 939 940 if (cpu_state) 940 if (cpu_state) 941 { 941 { 942 callee_PC = cpu_state->eip; 942 callee_PC = cpu_state->eip; 943 caller_frame = cpu_state->ebp; 943 caller_frame = cpu_state->ebp; 944 } 944 } 945 else 945 else 946 { 946 { 947 /* Skip the sos_backtrace() frame */ 947 /* Skip the sos_backtrace() frame */ 948 callee_PC = (sos_vaddr_t)__builtin_re 948 callee_PC = (sos_vaddr_t)__builtin_return_address(0); 949 caller_frame = (sos_vaddr_t)__builtin_fr 949 caller_frame = (sos_vaddr_t)__builtin_frame_address(1); 950 } 950 } 951 951 952 for(depth=0 ; depth < max_depth ; depth ++) 952 for(depth=0 ; depth < max_depth ; depth ++) 953 { 953 { 954 /* Call the callback */ 954 /* Call the callback */ 955 backtracer(callee_PC, caller_frame + 8, 955 backtracer(callee_PC, caller_frame + 8, depth, custom_arg); 956 956 957 /* If the frame address is funky, don't 957 /* If the frame address is funky, don't go further */ 958 if ( (caller_frame < stack_bottom) 958 if ( (caller_frame < stack_bottom) 959 || (caller_frame + 4 >= stack_botto 959 || (caller_frame + 4 >= stack_bottom + stack_size) ) 960 return depth; 960 return depth; 961 961 962 /* Go to caller frame */ 962 /* Go to caller frame */ 963 callee_PC = *((sos_vaddr_t*) (caller_ 963 callee_PC = *((sos_vaddr_t*) (caller_frame + 4)); 964 caller_frame = *((sos_vaddr_t*) caller_f 964 caller_frame = *((sos_vaddr_t*) caller_frame); 965 } 965 } 966 966 967 return depth; 967 return depth; 968 } 968 } 969 969 970 970 971 /* ******************************************* 971 /* ************************************************************* 972 * Function to manage the TSS. This function 972 * Function to manage the TSS. This function is not really "public": 973 * it is reserved to the assembler routines de 973 * it is reserved to the assembler routines defined in 974 * cpu_context_switch.S 974 * cpu_context_switch.S 975 * 975 * 976 * Update the kernel stack address so that the 976 * Update the kernel stack address so that the IRQ, syscalls and 977 * exception return in a correct stack locatio 977 * exception return in a correct stack location when coming back into 978 * kernel mode. 978 * kernel mode. 979 */ 979 */ 980 void 980 void 981 sos_cpu_context_update_kernel_tss(struct sos_c 981 sos_cpu_context_update_kernel_tss(struct sos_cpu_state *next_ctxt) 982 { 982 { 983 /* next_ctxt corresponds to an interrupted u 983 /* next_ctxt corresponds to an interrupted user thread ? */ 984 if (sos_cpu_context_is_in_user_mode(next_ctx 984 if (sos_cpu_context_is_in_user_mode(next_ctxt)) 985 { 985 { 986 /* 986 /* 987 * Yes: "next_ctxt" is an interrupted us 987 * Yes: "next_ctxt" is an interrupted user thread => we are 988 * going to switch to user mode ! Setup 988 * going to switch to user mode ! Setup the stack address so 989 * that the user thread "next_ctxt" can 989 * that the user thread "next_ctxt" can come back to the correct 990 * stack location when returning in kern 990 * stack location when returning in kernel mode. 991 * 991 * 992 * This stack location corresponds to th 992 * This stack location corresponds to the SP of the next user 993 * thread once its context has been tran 993 * thread once its context has been transferred on the CPU, ie 994 * once the CPU has executed all the pop 994 * once the CPU has executed all the pop/iret instruction of the 995 * context switch with privilege change. 995 * context switch with privilege change. 996 */ 996 */ 997 kernel_tss.esp0 = ((sos_vaddr_t)next_ctx 997 kernel_tss.esp0 = ((sos_vaddr_t)next_ctxt) 998 + sizeof(struct sos_cp 998 + sizeof(struct sos_cpu_ustate); 999 /* Note: no need to protect this agains 999 /* Note: no need to protect this agains IRQ because IRQs are not 1000 allowed to update it by themselves, 1000 allowed to update it by themselves, and they are not allowed 1001 to block */ 1001 to block */ 1002 } 1002 } 1003 else 1003 else 1004 { 1004 { 1005 /* No: No need to update kernel TSS whe 1005 /* No: No need to update kernel TSS when we stay in kernel 1006 mode */ 1006 mode */ 1007 } 1007 } 1008 } 1008 }
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