1 /* This file contains code for initialization of protected mode, to initialize 2 * code and data segment descriptors, and to initialize global descriptors 3 * for local descriptors in the process table. 4 */ 5 6 #include <assert.h> 7 #include <string.h> 8 9 #include <minix/cpufeature.h> 10 #include <sys/types.h> 11 #include "kernel/kernel.h" 12 13 #include "arch_proto.h" 14 15 #include <sys/exec.h> 16 #include <libexec.h> 17 18 #define INT_GATE_TYPE (INT_286_GATE | DESC_386_BIT) 19 #define TSS_TYPE (AVL_286_TSS | DESC_386_BIT) 20 21 /* This is OK initially, when the 1:1 mapping is still there. */ 22 char *video_mem = (char *) MULTIBOOT_VIDEO_BUFFER; 23 24 /* Storage for gdt, idt and tss. */ 25 struct segdesc_s gdt[GDT_SIZE] __aligned(DESC_SIZE); 26 struct gatedesc_s idt[IDT_SIZE] __aligned(DESC_SIZE); 27 struct tss_s tss[CONFIG_MAX_CPUS]; 28 29 u32_t k_percpu_stacks[CONFIG_MAX_CPUS]; 30 31 int prot_init_done = 0; 32 33 phys_bytes vir2phys(void *vir) 34 { 35 extern char _kern_vir_base, _kern_phys_base; /* in kernel.lds */ 36 u32_t offset = (vir_bytes) &_kern_vir_base - 37 (vir_bytes) &_kern_phys_base; 38 return (phys_bytes)vir - offset; 39 } 40 41 /*===========================================================================* 42 * enable_iop * 43 *===========================================================================*/ 44 void enable_iop(struct proc *pp) 45 { 46 /* Allow a user process to use I/O instructions. Change the I/O Permission 47 * Level bits in the psw. These specify least-privileged Current Permission 48 * Level allowed to execute I/O instructions. Users and servers have CPL 3. 49 * You can't have less privilege than that. Kernel has CPL 0, tasks CPL 1. 50 */ 51 pp->p_reg.psw |= 0x3000; 52 } 53 54 55 /*===========================================================================* 56 * sdesc * 57 *===========================================================================*/ 58 void sdesc(struct segdesc_s *segdp, phys_bytes base, vir_bytes size) 59 { 60 /* Fill in the size fields (base, limit and granularity) of a descriptor. */ 61 segdp->base_low = base; 62 segdp->base_middle = base >> BASE_MIDDLE_SHIFT; 63 segdp->base_high = base >> BASE_HIGH_SHIFT; 64 65 --size; /* convert to a limit, 0 size means 4G */ 66 if (size > BYTE_GRAN_MAX) { 67 segdp->limit_low = size >> PAGE_GRAN_SHIFT; 68 segdp->granularity = GRANULAR | (size >> 69 (PAGE_GRAN_SHIFT + GRANULARITY_SHIFT)); 70 } else { 71 segdp->limit_low = size; 72 segdp->granularity = size >> GRANULARITY_SHIFT; 73 } 74 segdp->granularity |= DEFAULT; /* means BIG for data seg */ 75 } 76 77 /*===========================================================================* 78 * init_dataseg * 79 *===========================================================================*/ 80 void init_param_dataseg(register struct segdesc_s *segdp, 81 phys_bytes base, vir_bytes size, const int privilege) 82 { 83 /* Build descriptor for a data segment. */ 84 sdesc(segdp, base, size); 85 segdp->access = (privilege << DPL_SHIFT) | (PRESENT | SEGMENT | 86 WRITEABLE | ACCESSED); 87 /* EXECUTABLE = 0, EXPAND_DOWN = 0, ACCESSED = 0 */ 88 } 89 90 void init_dataseg(int index, const int privilege) 91 { 92 init_param_dataseg(&gdt[index], 0, 0xFFFFFFFF, privilege); 93 } 94 95 /*===========================================================================* 96 * init_codeseg * 97 *===========================================================================*/ 98 static void init_codeseg(int index, int privilege) 99 { 100 /* Build descriptor for a code segment. */ 101 sdesc(&gdt[index], 0, 0xFFFFFFFF); 102 gdt[index].access = (privilege << DPL_SHIFT) 103 | (PRESENT | SEGMENT | EXECUTABLE | READABLE); 104 /* CONFORMING = 0, ACCESSED = 0 */ 105 } 106 107 static struct gate_table_s gate_table_pic[] = { 108 { hwint00, VECTOR( 0), INTR_PRIVILEGE }, 109 { hwint01, VECTOR( 1), INTR_PRIVILEGE }, 110 { hwint02, VECTOR( 2), INTR_PRIVILEGE }, 111 { hwint03, VECTOR( 3), INTR_PRIVILEGE }, 112 { hwint04, VECTOR( 4), INTR_PRIVILEGE }, 113 { hwint05, VECTOR( 5), INTR_PRIVILEGE }, 114 { hwint06, VECTOR( 6), INTR_PRIVILEGE }, 115 { hwint07, VECTOR( 7), INTR_PRIVILEGE }, 116 { hwint08, VECTOR( 8), INTR_PRIVILEGE }, 117 { hwint09, VECTOR( 9), INTR_PRIVILEGE }, 118 { hwint10, VECTOR(10), INTR_PRIVILEGE }, 119 { hwint11, VECTOR(11), INTR_PRIVILEGE }, 120 { hwint12, VECTOR(12), INTR_PRIVILEGE }, 121 { hwint13, VECTOR(13), INTR_PRIVILEGE }, 122 { hwint14, VECTOR(14), INTR_PRIVILEGE }, 123 { hwint15, VECTOR(15), INTR_PRIVILEGE }, 124 { NULL, 0, 0} 125 }; 126 127 static struct gate_table_s gate_table_exceptions[] = { 128 { divide_error, DIVIDE_VECTOR, INTR_PRIVILEGE }, 129 { single_step_exception, DEBUG_VECTOR, INTR_PRIVILEGE }, 130 { nmi, NMI_VECTOR, INTR_PRIVILEGE }, 131 { breakpoint_exception, BREAKPOINT_VECTOR, USER_PRIVILEGE }, 132 { overflow, OVERFLOW_VECTOR, USER_PRIVILEGE }, 133 { bounds_check, BOUNDS_VECTOR, INTR_PRIVILEGE }, 134 { inval_opcode, INVAL_OP_VECTOR, INTR_PRIVILEGE }, 135 { copr_not_available, COPROC_NOT_VECTOR, INTR_PRIVILEGE }, 136 { double_fault, DOUBLE_FAULT_VECTOR, INTR_PRIVILEGE }, 137 { copr_seg_overrun, COPROC_SEG_VECTOR, INTR_PRIVILEGE }, 138 { inval_tss, INVAL_TSS_VECTOR, INTR_PRIVILEGE }, 139 { segment_not_present, SEG_NOT_VECTOR, INTR_PRIVILEGE }, 140 { stack_exception, STACK_FAULT_VECTOR, INTR_PRIVILEGE }, 141 { general_protection, PROTECTION_VECTOR, INTR_PRIVILEGE }, 142 { page_fault, PAGE_FAULT_VECTOR, INTR_PRIVILEGE }, 143 { copr_error, COPROC_ERR_VECTOR, INTR_PRIVILEGE }, 144 { alignment_check, ALIGNMENT_CHECK_VECTOR, INTR_PRIVILEGE }, 145 { machine_check, MACHINE_CHECK_VECTOR, INTR_PRIVILEGE }, 146 { simd_exception, SIMD_EXCEPTION_VECTOR, INTR_PRIVILEGE }, 147 { ipc_entry_softint_orig, IPC_VECTOR_ORIG, USER_PRIVILEGE }, 148 { kernel_call_entry_orig, KERN_CALL_VECTOR_ORIG, USER_PRIVILEGE }, 149 { ipc_entry_softint_um, IPC_VECTOR_UM, USER_PRIVILEGE }, 150 { kernel_call_entry_um, KERN_CALL_VECTOR_UM, USER_PRIVILEGE }, 151 { NULL, 0, 0} 152 }; 153 154 int tss_init(unsigned cpu, void * kernel_stack) 155 { 156 struct tss_s * t = &tss[cpu]; 157 int index = TSS_INDEX(cpu); 158 struct segdesc_s *tssgdt; 159 160 tssgdt = &gdt[index]; 161 162 init_param_dataseg(tssgdt, (phys_bytes) t, 163 sizeof(struct tss_s), INTR_PRIVILEGE); 164 tssgdt->access = PRESENT | (INTR_PRIVILEGE << DPL_SHIFT) | TSS_TYPE; 165 166 /* Build TSS. */ 167 memset(t, 0, sizeof(*t)); 168 t->ds = t->es = t->fs = t->gs = t->ss0 = KERN_DS_SELECTOR; 169 t->cs = KERN_CS_SELECTOR; 170 t->iobase = sizeof(struct tss_s); /* empty i/o permissions map */ 171 172 /* 173 * make space for process pointer and cpu id and point to the first 174 * usable word 175 */ 176 k_percpu_stacks[cpu] = t->sp0 = ((unsigned) kernel_stack) - X86_STACK_TOP_RESERVED; 177 /* 178 * set the cpu id at the top of the stack so we know on which cpu is 179 * this stack in use when we trap to kernel 180 */ 181 *((reg_t *)(t->sp0 + 1 * sizeof(reg_t))) = cpu; 182 183 /* Set up Intel SYSENTER support if available. */ 184 if(minix_feature_flags & MKF_I386_INTEL_SYSENTER) { 185 ia32_msr_write(INTEL_MSR_SYSENTER_CS, 0, KERN_CS_SELECTOR); 186 ia32_msr_write(INTEL_MSR_SYSENTER_ESP, 0, t->sp0); 187 ia32_msr_write(INTEL_MSR_SYSENTER_EIP, 0, (u32_t) ipc_entry_sysenter); 188 } 189 190 /* Set up AMD SYSCALL support if available. */ 191 if(minix_feature_flags & MKF_I386_AMD_SYSCALL) { 192 u32_t msr_lo, msr_hi; 193 194 /* set SYSCALL ENABLE bit in EFER MSR */ 195 ia32_msr_read(AMD_MSR_EFER, &msr_hi, &msr_lo); 196 msr_lo |= AMD_EFER_SCE; 197 ia32_msr_write(AMD_MSR_EFER, msr_hi, msr_lo); 198 199 /* set STAR register value */ 200 #define set_star_cpu(forcpu) if(cpu == forcpu) { \ 201 ia32_msr_write(AMD_MSR_STAR, \ 202 ((u32_t)USER_CS_SELECTOR << 16) | (u32_t)KERN_CS_SELECTOR, \ 203 (u32_t) ipc_entry_syscall_cpu ## forcpu); } 204 set_star_cpu(0); 205 set_star_cpu(1); 206 set_star_cpu(2); 207 set_star_cpu(3); 208 set_star_cpu(4); 209 set_star_cpu(5); 210 set_star_cpu(6); 211 set_star_cpu(7); 212 assert(CONFIG_MAX_CPUS <= 8); 213 } 214 215 return SEG_SELECTOR(index); 216 } 217 218 phys_bytes init_segdesc(int gdt_index, void *base, int size) 219 { 220 struct desctableptr_s *dtp = (struct desctableptr_s *) &gdt[gdt_index]; 221 dtp->limit = size - 1; 222 dtp->base = (phys_bytes) base; 223 224 return (phys_bytes) dtp; 225 } 226 227 void int_gate(struct gatedesc_s *tab, 228 unsigned vec_nr, vir_bytes offset, unsigned dpl_type) 229 { 230 /* Build descriptor for an interrupt gate. */ 231 register struct gatedesc_s *idp; 232 233 idp = &tab[vec_nr]; 234 idp->offset_low = offset; 235 idp->selector = KERN_CS_SELECTOR; 236 idp->p_dpl_type = dpl_type; 237 idp->offset_high = offset >> OFFSET_HIGH_SHIFT; 238 } 239 240 void int_gate_idt(unsigned vec_nr, vir_bytes offset, unsigned dpl_type) 241 { 242 int_gate(idt, vec_nr, offset, dpl_type); 243 } 244 245 void idt_copy_vectors(struct gate_table_s * first) 246 { 247 struct gate_table_s *gtp; 248 for (gtp = first; gtp->gate; gtp++) { 249 int_gate(idt, gtp->vec_nr, (vir_bytes) gtp->gate, 250 PRESENT | INT_GATE_TYPE | 251 (gtp->privilege << DPL_SHIFT)); 252 } 253 } 254 255 void idt_copy_vectors_pic(void) 256 { 257 idt_copy_vectors(gate_table_pic); 258 } 259 260 void idt_init(void) 261 { 262 idt_copy_vectors_pic(); 263 idt_copy_vectors(gate_table_exceptions); 264 } 265 266 struct desctableptr_s gdt_desc, idt_desc; 267 268 void idt_reload(void) 269 { 270 x86_lidt(&idt_desc); 271 } 272 273 multiboot_module_t *bootmod(int pnr) 274 { 275 int i; 276 277 assert(pnr >= 0); 278 279 /* Search for desired process in boot process 280 * list. The first NR_TASKS ones do not correspond 281 * to a module, however, so we don't search those. 282 */ 283 for(i = NR_TASKS; i < NR_BOOT_PROCS; i++) { 284 int p; 285 p = i - NR_TASKS; 286 if(image[i].proc_nr == pnr) { 287 assert(p < MULTIBOOT_MAX_MODS); 288 assert(p < kinfo.mbi.mi_mods_count); 289 return &kinfo.module_list[p]; 290 } 291 } 292 293 panic("boot module %d not found", pnr); 294 } 295 296 int booting_cpu = 0; 297 298 void prot_load_selectors(void) 299 { 300 /* this function is called by both prot_init by the BSP and 301 * the early AP booting code in mpx.S by secondary CPU's. 302 * everything is set up the same except for the TSS that is per-CPU. 303 */ 304 x86_lgdt(&gdt_desc); /* Load gdt */ 305 idt_init(); 306 idt_reload(); 307 x86_lldt(LDT_SELECTOR); /* Load bogus ldt */ 308 x86_ltr(TSS_SELECTOR(booting_cpu)); 309 310 x86_load_kerncs(); 311 x86_load_ds(KERN_DS_SELECTOR); 312 x86_load_es(KERN_DS_SELECTOR); 313 x86_load_fs(KERN_DS_SELECTOR); 314 x86_load_gs(KERN_DS_SELECTOR); 315 x86_load_ss(KERN_DS_SELECTOR); 316 } 317 318 /*===========================================================================* 319 * prot_init * 320 *===========================================================================*/ 321 void prot_init(void) 322 { 323 extern char k_boot_stktop; 324 325 if(_cpufeature(_CPUF_I386_SYSENTER)) 326 minix_feature_flags |= MKF_I386_INTEL_SYSENTER; 327 if(_cpufeature(_CPUF_I386_SYSCALL)) 328 minix_feature_flags |= MKF_I386_AMD_SYSCALL; 329 330 memset(gdt, 0, sizeof(gdt)); 331 memset(idt, 0, sizeof(idt)); 332 333 /* Build GDT, IDT, IDT descriptors. */ 334 gdt_desc.base = (u32_t) gdt; 335 gdt_desc.limit = sizeof(gdt)-1; 336 idt_desc.base = (u32_t) idt; 337 idt_desc.limit = sizeof(idt)-1; 338 tss_init(0, &k_boot_stktop); 339 340 /* Build GDT */ 341 init_param_dataseg(&gdt[LDT_INDEX], 342 (phys_bytes) 0, 0, INTR_PRIVILEGE); /* unusable LDT */ 343 gdt[LDT_INDEX].access = PRESENT | LDT; 344 init_codeseg(KERN_CS_INDEX, INTR_PRIVILEGE); 345 init_dataseg(KERN_DS_INDEX, INTR_PRIVILEGE); 346 init_codeseg(USER_CS_INDEX, USER_PRIVILEGE); 347 init_dataseg(USER_DS_INDEX, USER_PRIVILEGE); 348 349 /* Currently the multiboot segments are loaded; which is fine, but 350 * let's replace them with the ones from our own GDT so we test 351 * right away whether they work as expected. 352 */ 353 prot_load_selectors(); 354 355 /* Set up a new post-relocate bootstrap pagetable so that 356 * we can map in VM, and we no longer rely on pre-relocated 357 * data. 358 */ 359 360 pg_clear(); 361 pg_identity(&kinfo); /* Still need 1:1 for lapic and video mem and such. */ 362 pg_mapkernel(); 363 pg_load(); 364 365 prot_init_done = 1; 366 } 367 368 static int alloc_for_vm = 0; 369 370 void arch_post_init(void) 371 { 372 /* Let memory mapping code know what's going on at bootstrap time */ 373 struct proc *vm; 374 vm = proc_addr(VM_PROC_NR); 375 get_cpulocal_var(ptproc) = vm; 376 pg_info(&vm->p_seg.p_cr3, &vm->p_seg.p_cr3_v); 377 } 378 379 static int libexec_pg_alloc(struct exec_info *execi, vir_bytes vaddr, size_t len) 380 { 381 pg_map(PG_ALLOCATEME, vaddr, vaddr+len, &kinfo); 382 pg_load(); 383 memset((char *) vaddr, 0, len); 384 alloc_for_vm += len; 385 return OK; 386 } 387 388 void arch_boot_proc(struct boot_image *ip, struct proc *rp) 389 { 390 multiboot_module_t *mod; 391 struct ps_strings *psp; 392 char *sp; 393 394 if(rp->p_nr < 0) return; 395 396 mod = bootmod(rp->p_nr); 397 398 /* Important special case: we put VM in the bootstrap pagetable 399 * so it can run. 400 */ 401 402 if(rp->p_nr == VM_PROC_NR) { 403 struct exec_info execi; 404 405 memset(&execi, 0, sizeof(execi)); 406 407 /* exec parameters */ 408 execi.stack_high = kinfo.user_sp; 409 execi.stack_size = 64 * 1024; /* not too crazy as it must be preallocated */ 410 execi.proc_e = ip->endpoint; 411 execi.hdr = (char *) mod->mod_start; /* phys mem direct */ 412 execi.filesize = execi.hdr_len = mod->mod_end - mod->mod_start; 413 strlcpy(execi.progname, ip->proc_name, sizeof(execi.progname)); 414 execi.frame_len = 0; 415 416 /* callbacks for use in the kernel */ 417 execi.copymem = libexec_copy_memcpy; 418 execi.clearmem = libexec_clear_memset; 419 execi.allocmem_prealloc_junk = libexec_pg_alloc; 420 execi.allocmem_prealloc_cleared = libexec_pg_alloc; 421 execi.allocmem_ondemand = libexec_pg_alloc; 422 execi.clearproc = NULL; 423 424 /* parse VM ELF binary and alloc/map it into bootstrap pagetable */ 425 if(libexec_load_elf(&execi) != OK) 426 panic("VM loading failed"); 427 428 /* Setup a ps_strings struct on the stack, pointing to the 429 * following argv, envp. */ 430 sp = (char *)execi.stack_high; 431 sp -= sizeof(struct ps_strings); 432 psp = (struct ps_strings *) sp; 433 434 /* Take the stack pointer down three words to give startup code 435 * something to use as "argc", "argv" and "envp". 436 */ 437 sp -= (sizeof(void *) + sizeof(void *) + sizeof(int)); 438 439 // linear address space, so it is available. 440 psp->ps_argvstr = (char **)(sp + sizeof(int)); 441 psp->ps_nargvstr = 0; 442 psp->ps_envstr = psp->ps_argvstr + sizeof(void *); 443 psp->ps_nenvstr = 0; 444 445 arch_proc_init(rp, execi.pc, (vir_bytes)sp, 446 execi.stack_high - sizeof(struct ps_strings), 447 ip->proc_name); 448 449 /* Free VM blob that was just copied into existence. */ 450 add_memmap(&kinfo, mod->mod_start, mod->mod_end-mod->mod_start); 451 mod->mod_end = mod->mod_start = 0; 452 453 /* Remember them */ 454 kinfo.vm_allocated_bytes = alloc_for_vm; 455 } 456 } 457