Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/vm86.c |
| 3 | * |
| 4 | * Copyright (C) 1994 Linus Torvalds |
| 5 | * |
| 6 | * 29 dec 2001 - Fixed oopses caused by unchecked access to the vm86 |
Christian Kujau | 624dffc | 2006-01-15 02:43:54 +0100 | [diff] [blame] | 7 | * stack - Manfred Spraul <manfred@colorfullife.com> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | * |
| 9 | * 22 mar 2002 - Manfred detected the stackfaults, but didn't handle |
| 10 | * them correctly. Now the emulation will be in a |
| 11 | * consistent state after stackfaults - Kasper Dupont |
| 12 | * <kasperd@daimi.au.dk> |
| 13 | * |
| 14 | * 22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont |
| 15 | * <kasperd@daimi.au.dk> |
| 16 | * |
| 17 | * ?? ??? 2002 - Fixed premature returns from handle_vm86_fault |
| 18 | * caused by Kasper Dupont's changes - Stas Sergeev |
| 19 | * |
| 20 | * 4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes. |
| 21 | * Kasper Dupont <kasperd@daimi.au.dk> |
| 22 | * |
| 23 | * 9 apr 2002 - Changed syntax of macros in handle_vm86_fault. |
| 24 | * Kasper Dupont <kasperd@daimi.au.dk> |
| 25 | * |
| 26 | * 9 apr 2002 - Changed stack access macros to jump to a label |
| 27 | * instead of returning to userspace. This simplifies |
| 28 | * do_int, and is needed by handle_vm6_fault. Kasper |
| 29 | * Dupont <kasperd@daimi.au.dk> |
| 30 | * |
| 31 | */ |
| 32 | |
Randy Dunlap | a941564 | 2006-01-11 12:17:48 -0800 | [diff] [blame] | 33 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | #include <linux/config.h> |
| 35 | #include <linux/errno.h> |
| 36 | #include <linux/interrupt.h> |
| 37 | #include <linux/sched.h> |
| 38 | #include <linux/kernel.h> |
| 39 | #include <linux/signal.h> |
| 40 | #include <linux/string.h> |
| 41 | #include <linux/mm.h> |
| 42 | #include <linux/smp.h> |
| 43 | #include <linux/smp_lock.h> |
| 44 | #include <linux/highmem.h> |
| 45 | #include <linux/ptrace.h> |
Jason Baron | 7e7f8a0 | 2006-01-31 16:56:28 -0500 | [diff] [blame] | 46 | #include <linux/audit.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | |
| 48 | #include <asm/uaccess.h> |
| 49 | #include <asm/io.h> |
| 50 | #include <asm/tlbflush.h> |
| 51 | #include <asm/irq.h> |
| 52 | |
| 53 | /* |
| 54 | * Known problems: |
| 55 | * |
| 56 | * Interrupt handling is not guaranteed: |
| 57 | * - a real x86 will disable all interrupts for one instruction |
| 58 | * after a "mov ss,xx" to make stack handling atomic even without |
| 59 | * the 'lss' instruction. We can't guarantee this in v86 mode, |
| 60 | * as the next instruction might result in a page fault or similar. |
| 61 | * - a real x86 will have interrupts disabled for one instruction |
| 62 | * past the 'sti' that enables them. We don't bother with all the |
| 63 | * details yet. |
| 64 | * |
| 65 | * Let's hope these problems do not actually matter for anything. |
| 66 | */ |
| 67 | |
| 68 | |
| 69 | #define KVM86 ((struct kernel_vm86_struct *)regs) |
| 70 | #define VMPI KVM86->vm86plus |
| 71 | |
| 72 | |
| 73 | /* |
| 74 | * 8- and 16-bit register defines.. |
| 75 | */ |
| 76 | #define AL(regs) (((unsigned char *)&((regs)->eax))[0]) |
| 77 | #define AH(regs) (((unsigned char *)&((regs)->eax))[1]) |
| 78 | #define IP(regs) (*(unsigned short *)&((regs)->eip)) |
| 79 | #define SP(regs) (*(unsigned short *)&((regs)->esp)) |
| 80 | |
| 81 | /* |
| 82 | * virtual flags (16 and 32-bit versions) |
| 83 | */ |
| 84 | #define VFLAGS (*(unsigned short *)&(current->thread.v86flags)) |
| 85 | #define VEFLAGS (current->thread.v86flags) |
| 86 | |
| 87 | #define set_flags(X,new,mask) \ |
| 88 | ((X) = ((X) & ~(mask)) | ((new) & (mask))) |
| 89 | |
| 90 | #define SAFE_MASK (0xDD5) |
| 91 | #define RETURN_MASK (0xDFF) |
| 92 | |
| 93 | #define VM86_REGS_PART2 orig_eax |
| 94 | #define VM86_REGS_SIZE1 \ |
| 95 | ( (unsigned)( & (((struct kernel_vm86_regs *)0)->VM86_REGS_PART2) ) ) |
| 96 | #define VM86_REGS_SIZE2 (sizeof(struct kernel_vm86_regs) - VM86_REGS_SIZE1) |
| 97 | |
| 98 | struct pt_regs * FASTCALL(save_v86_state(struct kernel_vm86_regs * regs)); |
| 99 | struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) |
| 100 | { |
| 101 | struct tss_struct *tss; |
| 102 | struct pt_regs *ret; |
| 103 | unsigned long tmp; |
| 104 | |
| 105 | /* |
| 106 | * This gets called from entry.S with interrupts disabled, but |
| 107 | * from process context. Enable interrupts here, before trying |
| 108 | * to access user space. |
| 109 | */ |
| 110 | local_irq_enable(); |
| 111 | |
| 112 | if (!current->thread.vm86_info) { |
| 113 | printk("no vm86_info: BAD\n"); |
| 114 | do_exit(SIGSEGV); |
| 115 | } |
| 116 | set_flags(regs->eflags, VEFLAGS, VIF_MASK | current->thread.v86mask); |
| 117 | tmp = copy_to_user(¤t->thread.vm86_info->regs,regs, VM86_REGS_SIZE1); |
| 118 | tmp += copy_to_user(¤t->thread.vm86_info->regs.VM86_REGS_PART2, |
| 119 | ®s->VM86_REGS_PART2, VM86_REGS_SIZE2); |
| 120 | tmp += put_user(current->thread.screen_bitmap,¤t->thread.vm86_info->screen_bitmap); |
| 121 | if (tmp) { |
| 122 | printk("vm86: could not access userspace vm86_info\n"); |
| 123 | do_exit(SIGSEGV); |
| 124 | } |
| 125 | |
| 126 | tss = &per_cpu(init_tss, get_cpu()); |
| 127 | current->thread.esp0 = current->thread.saved_esp0; |
| 128 | current->thread.sysenter_cs = __KERNEL_CS; |
| 129 | load_esp0(tss, ¤t->thread); |
| 130 | current->thread.saved_esp0 = 0; |
| 131 | put_cpu(); |
| 132 | |
| 133 | loadsegment(fs, current->thread.saved_fs); |
| 134 | loadsegment(gs, current->thread.saved_gs); |
| 135 | ret = KVM86->regs32; |
| 136 | return ret; |
| 137 | } |
| 138 | |
Hugh Dickins | 60ec558 | 2005-10-29 18:16:34 -0700 | [diff] [blame] | 139 | static void mark_screen_rdonly(struct mm_struct *mm) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | { |
| 141 | pgd_t *pgd; |
| 142 | pud_t *pud; |
| 143 | pmd_t *pmd; |
Hugh Dickins | 60ec558 | 2005-10-29 18:16:34 -0700 | [diff] [blame] | 144 | pte_t *pte; |
| 145 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | int i; |
| 147 | |
Hugh Dickins | 60ec558 | 2005-10-29 18:16:34 -0700 | [diff] [blame] | 148 | pgd = pgd_offset(mm, 0xA0000); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | if (pgd_none_or_clear_bad(pgd)) |
| 150 | goto out; |
| 151 | pud = pud_offset(pgd, 0xA0000); |
| 152 | if (pud_none_or_clear_bad(pud)) |
| 153 | goto out; |
| 154 | pmd = pmd_offset(pud, 0xA0000); |
| 155 | if (pmd_none_or_clear_bad(pmd)) |
| 156 | goto out; |
Hugh Dickins | 60ec558 | 2005-10-29 18:16:34 -0700 | [diff] [blame] | 157 | pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | for (i = 0; i < 32; i++) { |
| 159 | if (pte_present(*pte)) |
| 160 | set_pte(pte, pte_wrprotect(*pte)); |
| 161 | pte++; |
| 162 | } |
Hugh Dickins | 60ec558 | 2005-10-29 18:16:34 -0700 | [diff] [blame] | 163 | pte_unmap_unlock(pte, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | flush_tlb(); |
| 166 | } |
| 167 | |
| 168 | |
| 169 | |
| 170 | static int do_vm86_irq_handling(int subfunction, int irqnumber); |
| 171 | static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk); |
| 172 | |
| 173 | asmlinkage int sys_vm86old(struct pt_regs regs) |
| 174 | { |
| 175 | struct vm86_struct __user *v86 = (struct vm86_struct __user *)regs.ebx; |
| 176 | struct kernel_vm86_struct info; /* declare this _on top_, |
| 177 | * this avoids wasting of stack space. |
| 178 | * This remains on the stack until we |
| 179 | * return to 32 bit user space. |
| 180 | */ |
| 181 | struct task_struct *tsk; |
| 182 | int tmp, ret = -EPERM; |
| 183 | |
| 184 | tsk = current; |
| 185 | if (tsk->thread.saved_esp0) |
| 186 | goto out; |
| 187 | tmp = copy_from_user(&info, v86, VM86_REGS_SIZE1); |
| 188 | tmp += copy_from_user(&info.regs.VM86_REGS_PART2, &v86->regs.VM86_REGS_PART2, |
| 189 | (long)&info.vm86plus - (long)&info.regs.VM86_REGS_PART2); |
| 190 | ret = -EFAULT; |
| 191 | if (tmp) |
| 192 | goto out; |
| 193 | memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus); |
| 194 | info.regs32 = ®s; |
| 195 | tsk->thread.vm86_info = v86; |
| 196 | do_sys_vm86(&info, tsk); |
| 197 | ret = 0; /* we never return here */ |
| 198 | out: |
| 199 | return ret; |
| 200 | } |
| 201 | |
| 202 | |
| 203 | asmlinkage int sys_vm86(struct pt_regs regs) |
| 204 | { |
| 205 | struct kernel_vm86_struct info; /* declare this _on top_, |
| 206 | * this avoids wasting of stack space. |
| 207 | * This remains on the stack until we |
| 208 | * return to 32 bit user space. |
| 209 | */ |
| 210 | struct task_struct *tsk; |
| 211 | int tmp, ret; |
| 212 | struct vm86plus_struct __user *v86; |
| 213 | |
| 214 | tsk = current; |
| 215 | switch (regs.ebx) { |
| 216 | case VM86_REQUEST_IRQ: |
| 217 | case VM86_FREE_IRQ: |
| 218 | case VM86_GET_IRQ_BITS: |
| 219 | case VM86_GET_AND_RESET_IRQ: |
| 220 | ret = do_vm86_irq_handling(regs.ebx, (int)regs.ecx); |
| 221 | goto out; |
| 222 | case VM86_PLUS_INSTALL_CHECK: |
| 223 | /* NOTE: on old vm86 stuff this will return the error |
Jesper Juhl | e49332b | 2005-05-01 08:59:08 -0700 | [diff] [blame] | 224 | from access_ok(), because the subfunction is |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 225 | interpreted as (invalid) address to vm86_struct. |
| 226 | So the installation check works. |
| 227 | */ |
| 228 | ret = 0; |
| 229 | goto out; |
| 230 | } |
| 231 | |
| 232 | /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */ |
| 233 | ret = -EPERM; |
| 234 | if (tsk->thread.saved_esp0) |
| 235 | goto out; |
| 236 | v86 = (struct vm86plus_struct __user *)regs.ecx; |
| 237 | tmp = copy_from_user(&info, v86, VM86_REGS_SIZE1); |
| 238 | tmp += copy_from_user(&info.regs.VM86_REGS_PART2, &v86->regs.VM86_REGS_PART2, |
| 239 | (long)&info.regs32 - (long)&info.regs.VM86_REGS_PART2); |
| 240 | ret = -EFAULT; |
| 241 | if (tmp) |
| 242 | goto out; |
| 243 | info.regs32 = ®s; |
| 244 | info.vm86plus.is_vm86pus = 1; |
| 245 | tsk->thread.vm86_info = (struct vm86_struct __user *)v86; |
| 246 | do_sys_vm86(&info, tsk); |
| 247 | ret = 0; /* we never return here */ |
| 248 | out: |
| 249 | return ret; |
| 250 | } |
| 251 | |
| 252 | |
| 253 | static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk) |
| 254 | { |
| 255 | struct tss_struct *tss; |
Jason Baron | 7e7f8a0 | 2006-01-31 16:56:28 -0500 | [diff] [blame] | 256 | long eax; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | /* |
| 258 | * make sure the vm86() system call doesn't try to do anything silly |
| 259 | */ |
| 260 | info->regs.__null_ds = 0; |
| 261 | info->regs.__null_es = 0; |
| 262 | |
| 263 | /* we are clearing fs,gs later just before "jmp resume_userspace", |
| 264 | * because starting with Linux 2.1.x they aren't no longer saved/restored |
| 265 | */ |
| 266 | |
| 267 | /* |
| 268 | * The eflags register is also special: we cannot trust that the user |
| 269 | * has set it up safely, so this makes sure interrupt etc flags are |
| 270 | * inherited from protected mode. |
| 271 | */ |
| 272 | VEFLAGS = info->regs.eflags; |
| 273 | info->regs.eflags &= SAFE_MASK; |
| 274 | info->regs.eflags |= info->regs32->eflags & ~SAFE_MASK; |
| 275 | info->regs.eflags |= VM_MASK; |
| 276 | |
| 277 | switch (info->cpu_type) { |
| 278 | case CPU_286: |
| 279 | tsk->thread.v86mask = 0; |
| 280 | break; |
| 281 | case CPU_386: |
| 282 | tsk->thread.v86mask = NT_MASK | IOPL_MASK; |
| 283 | break; |
| 284 | case CPU_486: |
| 285 | tsk->thread.v86mask = AC_MASK | NT_MASK | IOPL_MASK; |
| 286 | break; |
| 287 | default: |
| 288 | tsk->thread.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK; |
| 289 | break; |
| 290 | } |
| 291 | |
| 292 | /* |
| 293 | * Save old state, set default return value (%eax) to 0 |
| 294 | */ |
| 295 | info->regs32->eax = 0; |
| 296 | tsk->thread.saved_esp0 = tsk->thread.esp0; |
Zachary Amsden | 4d37e7e | 2005-09-03 15:56:38 -0700 | [diff] [blame] | 297 | savesegment(fs, tsk->thread.saved_fs); |
| 298 | savesegment(gs, tsk->thread.saved_gs); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | |
| 300 | tss = &per_cpu(init_tss, get_cpu()); |
| 301 | tsk->thread.esp0 = (unsigned long) &info->VM86_TSS_ESP0; |
| 302 | if (cpu_has_sep) |
| 303 | tsk->thread.sysenter_cs = 0; |
| 304 | load_esp0(tss, &tsk->thread); |
| 305 | put_cpu(); |
| 306 | |
| 307 | tsk->thread.screen_bitmap = info->screen_bitmap; |
| 308 | if (info->flags & VM86_SCREEN_BITMAP) |
Hugh Dickins | 60ec558 | 2005-10-29 18:16:34 -0700 | [diff] [blame] | 309 | mark_screen_rdonly(tsk->mm); |
Jason Baron | 7e7f8a0 | 2006-01-31 16:56:28 -0500 | [diff] [blame] | 310 | __asm__ __volatile__("xorl %eax,%eax; movl %eax,%fs; movl %eax,%gs\n\t"); |
| 311 | __asm__ __volatile__("movl %%eax, %0\n" :"=r"(eax)); |
| 312 | |
| 313 | /*call audit_syscall_exit since we do not exit via the normal paths */ |
| 314 | if (unlikely(current->audit_context)) |
| 315 | audit_syscall_exit(current, AUDITSC_RESULT(eax), eax); |
| 316 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | __asm__ __volatile__( |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | "movl %0,%%esp\n\t" |
| 319 | "movl %1,%%ebp\n\t" |
| 320 | "jmp resume_userspace" |
| 321 | : /* no outputs */ |
Jason Baron | 7e7f8a0 | 2006-01-31 16:56:28 -0500 | [diff] [blame] | 322 | :"r" (&info->regs), "r" (task_thread_info(tsk))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 323 | /* we never return here */ |
| 324 | } |
| 325 | |
| 326 | static inline void return_to_32bit(struct kernel_vm86_regs * regs16, int retval) |
| 327 | { |
| 328 | struct pt_regs * regs32; |
| 329 | |
| 330 | regs32 = save_v86_state(regs16); |
| 331 | regs32->eax = retval; |
| 332 | __asm__ __volatile__("movl %0,%%esp\n\t" |
| 333 | "movl %1,%%ebp\n\t" |
| 334 | "jmp resume_userspace" |
| 335 | : : "r" (regs32), "r" (current_thread_info())); |
| 336 | } |
| 337 | |
| 338 | static inline void set_IF(struct kernel_vm86_regs * regs) |
| 339 | { |
| 340 | VEFLAGS |= VIF_MASK; |
| 341 | if (VEFLAGS & VIP_MASK) |
| 342 | return_to_32bit(regs, VM86_STI); |
| 343 | } |
| 344 | |
| 345 | static inline void clear_IF(struct kernel_vm86_regs * regs) |
| 346 | { |
| 347 | VEFLAGS &= ~VIF_MASK; |
| 348 | } |
| 349 | |
| 350 | static inline void clear_TF(struct kernel_vm86_regs * regs) |
| 351 | { |
| 352 | regs->eflags &= ~TF_MASK; |
| 353 | } |
| 354 | |
| 355 | static inline void clear_AC(struct kernel_vm86_regs * regs) |
| 356 | { |
| 357 | regs->eflags &= ~AC_MASK; |
| 358 | } |
| 359 | |
| 360 | /* It is correct to call set_IF(regs) from the set_vflags_* |
| 361 | * functions. However someone forgot to call clear_IF(regs) |
| 362 | * in the opposite case. |
| 363 | * After the command sequence CLI PUSHF STI POPF you should |
| 364 | * end up with interrups disabled, but you ended up with |
| 365 | * interrupts enabled. |
| 366 | * ( I was testing my own changes, but the only bug I |
| 367 | * could find was in a function I had not changed. ) |
| 368 | * [KD] |
| 369 | */ |
| 370 | |
| 371 | static inline void set_vflags_long(unsigned long eflags, struct kernel_vm86_regs * regs) |
| 372 | { |
| 373 | set_flags(VEFLAGS, eflags, current->thread.v86mask); |
| 374 | set_flags(regs->eflags, eflags, SAFE_MASK); |
| 375 | if (eflags & IF_MASK) |
| 376 | set_IF(regs); |
| 377 | else |
| 378 | clear_IF(regs); |
| 379 | } |
| 380 | |
| 381 | static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs * regs) |
| 382 | { |
| 383 | set_flags(VFLAGS, flags, current->thread.v86mask); |
| 384 | set_flags(regs->eflags, flags, SAFE_MASK); |
| 385 | if (flags & IF_MASK) |
| 386 | set_IF(regs); |
| 387 | else |
| 388 | clear_IF(regs); |
| 389 | } |
| 390 | |
| 391 | static inline unsigned long get_vflags(struct kernel_vm86_regs * regs) |
| 392 | { |
| 393 | unsigned long flags = regs->eflags & RETURN_MASK; |
| 394 | |
| 395 | if (VEFLAGS & VIF_MASK) |
| 396 | flags |= IF_MASK; |
| 397 | flags |= IOPL_MASK; |
| 398 | return flags | (VEFLAGS & current->thread.v86mask); |
| 399 | } |
| 400 | |
| 401 | static inline int is_revectored(int nr, struct revectored_struct * bitmap) |
| 402 | { |
| 403 | __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0" |
| 404 | :"=r" (nr) |
| 405 | :"m" (*bitmap),"r" (nr)); |
| 406 | return nr; |
| 407 | } |
| 408 | |
| 409 | #define val_byte(val, n) (((__u8 *)&val)[n]) |
| 410 | |
| 411 | #define pushb(base, ptr, val, err_label) \ |
| 412 | do { \ |
| 413 | __u8 __val = val; \ |
| 414 | ptr--; \ |
| 415 | if (put_user(__val, base + ptr) < 0) \ |
| 416 | goto err_label; \ |
| 417 | } while(0) |
| 418 | |
| 419 | #define pushw(base, ptr, val, err_label) \ |
| 420 | do { \ |
| 421 | __u16 __val = val; \ |
| 422 | ptr--; \ |
| 423 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ |
| 424 | goto err_label; \ |
| 425 | ptr--; \ |
| 426 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ |
| 427 | goto err_label; \ |
| 428 | } while(0) |
| 429 | |
| 430 | #define pushl(base, ptr, val, err_label) \ |
| 431 | do { \ |
| 432 | __u32 __val = val; \ |
| 433 | ptr--; \ |
| 434 | if (put_user(val_byte(__val, 3), base + ptr) < 0) \ |
| 435 | goto err_label; \ |
| 436 | ptr--; \ |
| 437 | if (put_user(val_byte(__val, 2), base + ptr) < 0) \ |
| 438 | goto err_label; \ |
| 439 | ptr--; \ |
| 440 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ |
| 441 | goto err_label; \ |
| 442 | ptr--; \ |
| 443 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ |
| 444 | goto err_label; \ |
| 445 | } while(0) |
| 446 | |
| 447 | #define popb(base, ptr, err_label) \ |
| 448 | ({ \ |
| 449 | __u8 __res; \ |
| 450 | if (get_user(__res, base + ptr) < 0) \ |
| 451 | goto err_label; \ |
| 452 | ptr++; \ |
| 453 | __res; \ |
| 454 | }) |
| 455 | |
| 456 | #define popw(base, ptr, err_label) \ |
| 457 | ({ \ |
| 458 | __u16 __res; \ |
| 459 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ |
| 460 | goto err_label; \ |
| 461 | ptr++; \ |
| 462 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ |
| 463 | goto err_label; \ |
| 464 | ptr++; \ |
| 465 | __res; \ |
| 466 | }) |
| 467 | |
| 468 | #define popl(base, ptr, err_label) \ |
| 469 | ({ \ |
| 470 | __u32 __res; \ |
| 471 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ |
| 472 | goto err_label; \ |
| 473 | ptr++; \ |
| 474 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ |
| 475 | goto err_label; \ |
| 476 | ptr++; \ |
| 477 | if (get_user(val_byte(__res, 2), base + ptr) < 0) \ |
| 478 | goto err_label; \ |
| 479 | ptr++; \ |
| 480 | if (get_user(val_byte(__res, 3), base + ptr) < 0) \ |
| 481 | goto err_label; \ |
| 482 | ptr++; \ |
| 483 | __res; \ |
| 484 | }) |
| 485 | |
| 486 | /* There are so many possible reasons for this function to return |
| 487 | * VM86_INTx, so adding another doesn't bother me. We can expect |
| 488 | * userspace programs to be able to handle it. (Getting a problem |
| 489 | * in userspace is always better than an Oops anyway.) [KD] |
| 490 | */ |
| 491 | static void do_int(struct kernel_vm86_regs *regs, int i, |
| 492 | unsigned char __user * ssp, unsigned short sp) |
| 493 | { |
| 494 | unsigned long __user *intr_ptr; |
| 495 | unsigned long segoffs; |
| 496 | |
| 497 | if (regs->cs == BIOSSEG) |
| 498 | goto cannot_handle; |
| 499 | if (is_revectored(i, &KVM86->int_revectored)) |
| 500 | goto cannot_handle; |
| 501 | if (i==0x21 && is_revectored(AH(regs),&KVM86->int21_revectored)) |
| 502 | goto cannot_handle; |
| 503 | intr_ptr = (unsigned long __user *) (i << 2); |
| 504 | if (get_user(segoffs, intr_ptr)) |
| 505 | goto cannot_handle; |
| 506 | if ((segoffs >> 16) == BIOSSEG) |
| 507 | goto cannot_handle; |
| 508 | pushw(ssp, sp, get_vflags(regs), cannot_handle); |
| 509 | pushw(ssp, sp, regs->cs, cannot_handle); |
| 510 | pushw(ssp, sp, IP(regs), cannot_handle); |
| 511 | regs->cs = segoffs >> 16; |
| 512 | SP(regs) -= 6; |
| 513 | IP(regs) = segoffs & 0xffff; |
| 514 | clear_TF(regs); |
| 515 | clear_IF(regs); |
| 516 | clear_AC(regs); |
| 517 | return; |
| 518 | |
| 519 | cannot_handle: |
| 520 | return_to_32bit(regs, VM86_INTx + (i << 8)); |
| 521 | } |
| 522 | |
| 523 | int handle_vm86_trap(struct kernel_vm86_regs * regs, long error_code, int trapno) |
| 524 | { |
| 525 | if (VMPI.is_vm86pus) { |
| 526 | if ( (trapno==3) || (trapno==1) ) |
| 527 | return_to_32bit(regs, VM86_TRAP + (trapno << 8)); |
| 528 | do_int(regs, trapno, (unsigned char __user *) (regs->ss << 4), SP(regs)); |
| 529 | return 0; |
| 530 | } |
| 531 | if (trapno !=1) |
| 532 | return 1; /* we let this handle by the calling routine */ |
| 533 | if (current->ptrace & PT_PTRACED) { |
| 534 | unsigned long flags; |
| 535 | spin_lock_irqsave(¤t->sighand->siglock, flags); |
| 536 | sigdelset(¤t->blocked, SIGTRAP); |
| 537 | recalc_sigpending(); |
| 538 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); |
| 539 | } |
| 540 | send_sig(SIGTRAP, current, 1); |
| 541 | current->thread.trap_no = trapno; |
| 542 | current->thread.error_code = error_code; |
| 543 | return 0; |
| 544 | } |
| 545 | |
| 546 | void handle_vm86_fault(struct kernel_vm86_regs * regs, long error_code) |
| 547 | { |
| 548 | unsigned char opcode; |
| 549 | unsigned char __user *csp; |
| 550 | unsigned char __user *ssp; |
Petr Tesarik | 5fd75eb | 2005-09-03 15:56:28 -0700 | [diff] [blame] | 551 | unsigned short ip, sp, orig_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | int data32, pref_done; |
| 553 | |
| 554 | #define CHECK_IF_IN_TRAP \ |
| 555 | if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \ |
| 556 | newflags |= TF_MASK |
| 557 | #define VM86_FAULT_RETURN do { \ |
| 558 | if (VMPI.force_return_for_pic && (VEFLAGS & (IF_MASK | VIF_MASK))) \ |
| 559 | return_to_32bit(regs, VM86_PICRETURN); \ |
Petr Tesarik | 5fd75eb | 2005-09-03 15:56:28 -0700 | [diff] [blame] | 560 | if (orig_flags & TF_MASK) \ |
| 561 | handle_vm86_trap(regs, 0, 1); \ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 562 | return; } while (0) |
| 563 | |
Petr Tesarik | 5fd75eb | 2005-09-03 15:56:28 -0700 | [diff] [blame] | 564 | orig_flags = *(unsigned short *)®s->eflags; |
| 565 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | csp = (unsigned char __user *) (regs->cs << 4); |
| 567 | ssp = (unsigned char __user *) (regs->ss << 4); |
| 568 | sp = SP(regs); |
| 569 | ip = IP(regs); |
| 570 | |
| 571 | data32 = 0; |
| 572 | pref_done = 0; |
| 573 | do { |
| 574 | switch (opcode = popb(csp, ip, simulate_sigsegv)) { |
| 575 | case 0x66: /* 32-bit data */ data32=1; break; |
| 576 | case 0x67: /* 32-bit address */ break; |
| 577 | case 0x2e: /* CS */ break; |
| 578 | case 0x3e: /* DS */ break; |
| 579 | case 0x26: /* ES */ break; |
| 580 | case 0x36: /* SS */ break; |
| 581 | case 0x65: /* GS */ break; |
| 582 | case 0x64: /* FS */ break; |
| 583 | case 0xf2: /* repnz */ break; |
| 584 | case 0xf3: /* rep */ break; |
| 585 | default: pref_done = 1; |
| 586 | } |
| 587 | } while (!pref_done); |
| 588 | |
| 589 | switch (opcode) { |
| 590 | |
| 591 | /* pushf */ |
| 592 | case 0x9c: |
| 593 | if (data32) { |
| 594 | pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); |
| 595 | SP(regs) -= 4; |
| 596 | } else { |
| 597 | pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); |
| 598 | SP(regs) -= 2; |
| 599 | } |
| 600 | IP(regs) = ip; |
| 601 | VM86_FAULT_RETURN; |
| 602 | |
| 603 | /* popf */ |
| 604 | case 0x9d: |
| 605 | { |
| 606 | unsigned long newflags; |
| 607 | if (data32) { |
| 608 | newflags=popl(ssp, sp, simulate_sigsegv); |
| 609 | SP(regs) += 4; |
| 610 | } else { |
| 611 | newflags = popw(ssp, sp, simulate_sigsegv); |
| 612 | SP(regs) += 2; |
| 613 | } |
| 614 | IP(regs) = ip; |
| 615 | CHECK_IF_IN_TRAP; |
| 616 | if (data32) { |
| 617 | set_vflags_long(newflags, regs); |
| 618 | } else { |
| 619 | set_vflags_short(newflags, regs); |
| 620 | } |
| 621 | VM86_FAULT_RETURN; |
| 622 | } |
| 623 | |
| 624 | /* int xx */ |
| 625 | case 0xcd: { |
| 626 | int intno=popb(csp, ip, simulate_sigsegv); |
| 627 | IP(regs) = ip; |
| 628 | if (VMPI.vm86dbg_active) { |
| 629 | if ( (1 << (intno &7)) & VMPI.vm86dbg_intxxtab[intno >> 3] ) |
| 630 | return_to_32bit(regs, VM86_INTx + (intno << 8)); |
| 631 | } |
| 632 | do_int(regs, intno, ssp, sp); |
| 633 | return; |
| 634 | } |
| 635 | |
| 636 | /* iret */ |
| 637 | case 0xcf: |
| 638 | { |
| 639 | unsigned long newip; |
| 640 | unsigned long newcs; |
| 641 | unsigned long newflags; |
| 642 | if (data32) { |
| 643 | newip=popl(ssp, sp, simulate_sigsegv); |
| 644 | newcs=popl(ssp, sp, simulate_sigsegv); |
| 645 | newflags=popl(ssp, sp, simulate_sigsegv); |
| 646 | SP(regs) += 12; |
| 647 | } else { |
| 648 | newip = popw(ssp, sp, simulate_sigsegv); |
| 649 | newcs = popw(ssp, sp, simulate_sigsegv); |
| 650 | newflags = popw(ssp, sp, simulate_sigsegv); |
| 651 | SP(regs) += 6; |
| 652 | } |
| 653 | IP(regs) = newip; |
| 654 | regs->cs = newcs; |
| 655 | CHECK_IF_IN_TRAP; |
| 656 | if (data32) { |
| 657 | set_vflags_long(newflags, regs); |
| 658 | } else { |
| 659 | set_vflags_short(newflags, regs); |
| 660 | } |
| 661 | VM86_FAULT_RETURN; |
| 662 | } |
| 663 | |
| 664 | /* cli */ |
| 665 | case 0xfa: |
| 666 | IP(regs) = ip; |
| 667 | clear_IF(regs); |
| 668 | VM86_FAULT_RETURN; |
| 669 | |
| 670 | /* sti */ |
| 671 | /* |
| 672 | * Damn. This is incorrect: the 'sti' instruction should actually |
| 673 | * enable interrupts after the /next/ instruction. Not good. |
| 674 | * |
| 675 | * Probably needs some horsing around with the TF flag. Aiee.. |
| 676 | */ |
| 677 | case 0xfb: |
| 678 | IP(regs) = ip; |
| 679 | set_IF(regs); |
| 680 | VM86_FAULT_RETURN; |
| 681 | |
| 682 | default: |
| 683 | return_to_32bit(regs, VM86_UNKNOWN); |
| 684 | } |
| 685 | |
| 686 | return; |
| 687 | |
| 688 | simulate_sigsegv: |
| 689 | /* FIXME: After a long discussion with Stas we finally |
| 690 | * agreed, that this is wrong. Here we should |
| 691 | * really send a SIGSEGV to the user program. |
| 692 | * But how do we create the correct context? We |
| 693 | * are inside a general protection fault handler |
| 694 | * and has just returned from a page fault handler. |
| 695 | * The correct context for the signal handler |
| 696 | * should be a mixture of the two, but how do we |
| 697 | * get the information? [KD] |
| 698 | */ |
| 699 | return_to_32bit(regs, VM86_UNKNOWN); |
| 700 | } |
| 701 | |
| 702 | /* ---------------- vm86 special IRQ passing stuff ----------------- */ |
| 703 | |
| 704 | #define VM86_IRQNAME "vm86irq" |
| 705 | |
| 706 | static struct vm86_irqs { |
| 707 | struct task_struct *tsk; |
| 708 | int sig; |
| 709 | } vm86_irqs[16]; |
| 710 | |
| 711 | static DEFINE_SPINLOCK(irqbits_lock); |
| 712 | static int irqbits; |
| 713 | |
| 714 | #define ALLOWED_SIGS ( 1 /* 0 = don't send a signal */ \ |
| 715 | | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ |
| 716 | | (1 << SIGUNUSED) ) |
| 717 | |
| 718 | static irqreturn_t irq_handler(int intno, void *dev_id, struct pt_regs * regs) |
| 719 | { |
| 720 | int irq_bit; |
| 721 | unsigned long flags; |
| 722 | |
| 723 | spin_lock_irqsave(&irqbits_lock, flags); |
| 724 | irq_bit = 1 << intno; |
| 725 | if ((irqbits & irq_bit) || ! vm86_irqs[intno].tsk) |
| 726 | goto out; |
| 727 | irqbits |= irq_bit; |
| 728 | if (vm86_irqs[intno].sig) |
| 729 | send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 730 | /* |
| 731 | * IRQ will be re-enabled when user asks for the irq (whether |
| 732 | * polling or as a result of the signal) |
| 733 | */ |
Pavel Pisa | ad67142 | 2005-05-01 08:58:52 -0700 | [diff] [blame] | 734 | disable_irq_nosync(intno); |
| 735 | spin_unlock_irqrestore(&irqbits_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | return IRQ_HANDLED; |
| 737 | |
| 738 | out: |
| 739 | spin_unlock_irqrestore(&irqbits_lock, flags); |
| 740 | return IRQ_NONE; |
| 741 | } |
| 742 | |
| 743 | static inline void free_vm86_irq(int irqnumber) |
| 744 | { |
| 745 | unsigned long flags; |
| 746 | |
| 747 | free_irq(irqnumber, NULL); |
| 748 | vm86_irqs[irqnumber].tsk = NULL; |
| 749 | |
| 750 | spin_lock_irqsave(&irqbits_lock, flags); |
| 751 | irqbits &= ~(1 << irqnumber); |
| 752 | spin_unlock_irqrestore(&irqbits_lock, flags); |
| 753 | } |
| 754 | |
| 755 | void release_vm86_irqs(struct task_struct *task) |
| 756 | { |
| 757 | int i; |
| 758 | for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) |
| 759 | if (vm86_irqs[i].tsk == task) |
| 760 | free_vm86_irq(i); |
| 761 | } |
| 762 | |
| 763 | static inline int get_and_reset_irq(int irqnumber) |
| 764 | { |
| 765 | int bit; |
| 766 | unsigned long flags; |
Pavel Pisa | ad67142 | 2005-05-01 08:58:52 -0700 | [diff] [blame] | 767 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 768 | |
| 769 | if (invalid_vm86_irq(irqnumber)) return 0; |
| 770 | if (vm86_irqs[irqnumber].tsk != current) return 0; |
| 771 | spin_lock_irqsave(&irqbits_lock, flags); |
| 772 | bit = irqbits & (1 << irqnumber); |
| 773 | irqbits &= ~bit; |
Pavel Pisa | ad67142 | 2005-05-01 08:58:52 -0700 | [diff] [blame] | 774 | if (bit) { |
| 775 | enable_irq(irqnumber); |
| 776 | ret = 1; |
| 777 | } |
| 778 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 779 | spin_unlock_irqrestore(&irqbits_lock, flags); |
Pavel Pisa | ad67142 | 2005-05-01 08:58:52 -0700 | [diff] [blame] | 780 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 781 | } |
| 782 | |
| 783 | |
| 784 | static int do_vm86_irq_handling(int subfunction, int irqnumber) |
| 785 | { |
| 786 | int ret; |
| 787 | switch (subfunction) { |
| 788 | case VM86_GET_AND_RESET_IRQ: { |
| 789 | return get_and_reset_irq(irqnumber); |
| 790 | } |
| 791 | case VM86_GET_IRQ_BITS: { |
| 792 | return irqbits; |
| 793 | } |
| 794 | case VM86_REQUEST_IRQ: { |
| 795 | int sig = irqnumber >> 8; |
| 796 | int irq = irqnumber & 255; |
| 797 | if (!capable(CAP_SYS_ADMIN)) return -EPERM; |
| 798 | if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; |
| 799 | if (invalid_vm86_irq(irq)) return -EPERM; |
| 800 | if (vm86_irqs[irq].tsk) return -EPERM; |
| 801 | ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); |
| 802 | if (ret) return ret; |
| 803 | vm86_irqs[irq].sig = sig; |
| 804 | vm86_irqs[irq].tsk = current; |
| 805 | return irq; |
| 806 | } |
| 807 | case VM86_FREE_IRQ: { |
| 808 | if (invalid_vm86_irq(irqnumber)) return -EPERM; |
| 809 | if (!vm86_irqs[irqnumber].tsk) return 0; |
| 810 | if (vm86_irqs[irqnumber].tsk != current) return -EPERM; |
| 811 | free_vm86_irq(irqnumber); |
| 812 | return 0; |
| 813 | } |
| 814 | } |
| 815 | return -EINVAL; |
| 816 | } |
| 817 | |