2 * Copyright (C) 1994 Linus Torvalds
4 * 29 dec 2001 - Fixed oopses caused by unchecked access to the vm86
5 * stack - Manfred Spraul <manfred@colorfullife.com>
7 * 22 mar 2002 - Manfred detected the stackfaults, but didn't handle
8 * them correctly. Now the emulation will be in a
9 * consistent state after stackfaults - Kasper Dupont
10 * <kasperd@daimi.au.dk>
12 * 22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont
13 * <kasperd@daimi.au.dk>
15 * ?? ??? 2002 - Fixed premature returns from handle_vm86_fault
16 * caused by Kasper Dupont's changes - Stas Sergeev
18 * 4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes.
19 * Kasper Dupont <kasperd@daimi.au.dk>
21 * 9 apr 2002 - Changed syntax of macros in handle_vm86_fault.
22 * Kasper Dupont <kasperd@daimi.au.dk>
24 * 9 apr 2002 - Changed stack access macros to jump to a label
25 * instead of returning to userspace. This simplifies
26 * do_int, and is needed by handle_vm6_fault. Kasper
27 * Dupont <kasperd@daimi.au.dk>
31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33 #include <linux/capability.h>
34 #include <linux/errno.h>
35 #include <linux/interrupt.h>
36 #include <linux/syscalls.h>
37 #include <linux/sched.h>
38 #include <linux/kernel.h>
39 #include <linux/signal.h>
40 #include <linux/string.h>
42 #include <linux/smp.h>
43 #include <linux/highmem.h>
44 #include <linux/ptrace.h>
45 #include <linux/audit.h>
46 #include <linux/stddef.h>
47 #include <linux/slab.h>
49 #include <asm/uaccess.h>
51 #include <asm/tlbflush.h>
53 #include <asm/traps.h>
59 * Interrupt handling is not guaranteed:
60 * - a real x86 will disable all interrupts for one instruction
61 * after a "mov ss,xx" to make stack handling atomic even without
62 * the 'lss' instruction. We can't guarantee this in v86 mode,
63 * as the next instruction might result in a page fault or similar.
64 * - a real x86 will have interrupts disabled for one instruction
65 * past the 'sti' that enables them. We don't bother with all the
68 * Let's hope these problems do not actually matter for anything.
73 * 8- and 16-bit register defines..
75 #define AL(regs) (((unsigned char *)&((regs)->pt.ax))[0])
76 #define AH(regs) (((unsigned char *)&((regs)->pt.ax))[1])
77 #define IP(regs) (*(unsigned short *)&((regs)->pt.ip))
78 #define SP(regs) (*(unsigned short *)&((regs)->pt.sp))
81 * virtual flags (16 and 32-bit versions)
83 #define VFLAGS (*(unsigned short *)&(current->thread.vm86->veflags))
84 #define VEFLAGS (current->thread.vm86->veflags)
86 #define set_flags(X, new, mask) \
87 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
89 #define SAFE_MASK (0xDD5)
90 #define RETURN_MASK (0xDFF)
92 void save_v86_state(struct kernel_vm86_regs
*regs
, int retval
)
94 struct tss_struct
*tss
;
95 struct task_struct
*tsk
= current
;
96 struct vm86plus_struct __user
*user
;
97 struct vm86
*vm86
= current
->thread
.vm86
;
101 * This gets called from entry.S with interrupts disabled, but
102 * from process context. Enable interrupts here, before trying
103 * to access user space.
107 if (!vm86
|| !vm86
->user_vm86
) {
108 pr_alert("no user_vm86: BAD\n");
111 set_flags(regs
->pt
.flags
, VEFLAGS
, X86_EFLAGS_VIF
| vm86
->veflags_mask
);
112 user
= vm86
->user_vm86
;
114 if (!access_ok(VERIFY_WRITE
, user
, vm86
->vm86plus
.is_vm86pus
?
115 sizeof(struct vm86plus_struct
) :
116 sizeof(struct vm86_struct
))) {
117 pr_alert("could not access userspace vm86 info\n");
122 put_user_ex(regs
->pt
.bx
, &user
->regs
.ebx
);
123 put_user_ex(regs
->pt
.cx
, &user
->regs
.ecx
);
124 put_user_ex(regs
->pt
.dx
, &user
->regs
.edx
);
125 put_user_ex(regs
->pt
.si
, &user
->regs
.esi
);
126 put_user_ex(regs
->pt
.di
, &user
->regs
.edi
);
127 put_user_ex(regs
->pt
.bp
, &user
->regs
.ebp
);
128 put_user_ex(regs
->pt
.ax
, &user
->regs
.eax
);
129 put_user_ex(regs
->pt
.ip
, &user
->regs
.eip
);
130 put_user_ex(regs
->pt
.cs
, &user
->regs
.cs
);
131 put_user_ex(regs
->pt
.flags
, &user
->regs
.eflags
);
132 put_user_ex(regs
->pt
.sp
, &user
->regs
.esp
);
133 put_user_ex(regs
->pt
.ss
, &user
->regs
.ss
);
134 put_user_ex(regs
->es
, &user
->regs
.es
);
135 put_user_ex(regs
->ds
, &user
->regs
.ds
);
136 put_user_ex(regs
->fs
, &user
->regs
.fs
);
137 put_user_ex(regs
->gs
, &user
->regs
.gs
);
139 put_user_ex(vm86
->screen_bitmap
, &user
->screen_bitmap
);
140 } put_user_catch(err
);
142 pr_alert("could not access userspace vm86 info\n");
146 tss
= &per_cpu(cpu_tss
, get_cpu());
147 tsk
->thread
.sp0
= vm86
->saved_sp0
;
148 tsk
->thread
.sysenter_cs
= __KERNEL_CS
;
149 load_sp0(tss
, &tsk
->thread
);
153 memcpy(®s
->pt
, &vm86
->regs32
, sizeof(struct pt_regs
));
155 lazy_load_gs(vm86
->regs32
.gs
);
157 regs
->pt
.ax
= retval
;
160 static void mark_screen_rdonly(struct mm_struct
*mm
)
169 down_write(&mm
->mmap_sem
);
170 pgd
= pgd_offset(mm
, 0xA0000);
171 if (pgd_none_or_clear_bad(pgd
))
173 pud
= pud_offset(pgd
, 0xA0000);
174 if (pud_none_or_clear_bad(pud
))
176 pmd
= pmd_offset(pud
, 0xA0000);
177 split_huge_page_pmd_mm(mm
, 0xA0000, pmd
);
178 if (pmd_none_or_clear_bad(pmd
))
180 pte
= pte_offset_map_lock(mm
, pmd
, 0xA0000, &ptl
);
181 for (i
= 0; i
< 32; i
++) {
182 if (pte_present(*pte
))
183 set_pte(pte
, pte_wrprotect(*pte
));
186 pte_unmap_unlock(pte
, ptl
);
188 up_write(&mm
->mmap_sem
);
194 static int do_vm86_irq_handling(int subfunction
, int irqnumber
);
195 static long do_sys_vm86(struct vm86plus_struct __user
*user_vm86
, bool plus
);
197 SYSCALL_DEFINE1(vm86old
, struct vm86_struct __user
*, user_vm86
)
199 return do_sys_vm86((struct vm86plus_struct __user
*) user_vm86
, false);
203 SYSCALL_DEFINE2(vm86
, unsigned long, cmd
, unsigned long, arg
)
206 case VM86_REQUEST_IRQ
:
208 case VM86_GET_IRQ_BITS
:
209 case VM86_GET_AND_RESET_IRQ
:
210 return do_vm86_irq_handling(cmd
, (int)arg
);
211 case VM86_PLUS_INSTALL_CHECK
:
213 * NOTE: on old vm86 stuff this will return the error
214 * from access_ok(), because the subfunction is
215 * interpreted as (invalid) address to vm86_struct.
216 * So the installation check works.
221 /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */
222 return do_sys_vm86((struct vm86plus_struct __user
*) arg
, true);
226 static long do_sys_vm86(struct vm86plus_struct __user
*user_vm86
, bool plus
)
228 struct tss_struct
*tss
;
229 struct task_struct
*tsk
= current
;
230 struct vm86
*vm86
= tsk
->thread
.vm86
;
231 struct kernel_vm86_regs vm86regs
;
232 struct pt_regs
*regs
= current_pt_regs();
233 unsigned long err
= 0;
236 if (!(vm86
= kzalloc(sizeof(*vm86
), GFP_KERNEL
)))
238 tsk
->thread
.vm86
= vm86
;
243 if (!access_ok(VERIFY_READ
, user_vm86
, plus
?
244 sizeof(struct vm86_struct
) :
245 sizeof(struct vm86plus_struct
)))
248 memset(&vm86regs
, 0, sizeof(vm86regs
));
251 get_user_ex(vm86regs
.pt
.bx
, &user_vm86
->regs
.ebx
);
252 get_user_ex(vm86regs
.pt
.cx
, &user_vm86
->regs
.ecx
);
253 get_user_ex(vm86regs
.pt
.dx
, &user_vm86
->regs
.edx
);
254 get_user_ex(vm86regs
.pt
.si
, &user_vm86
->regs
.esi
);
255 get_user_ex(vm86regs
.pt
.di
, &user_vm86
->regs
.edi
);
256 get_user_ex(vm86regs
.pt
.bp
, &user_vm86
->regs
.ebp
);
257 get_user_ex(vm86regs
.pt
.ax
, &user_vm86
->regs
.eax
);
258 get_user_ex(vm86regs
.pt
.ip
, &user_vm86
->regs
.eip
);
259 get_user_ex(seg
, &user_vm86
->regs
.cs
);
260 vm86regs
.pt
.cs
= seg
;
261 get_user_ex(vm86regs
.pt
.flags
, &user_vm86
->regs
.eflags
);
262 get_user_ex(vm86regs
.pt
.sp
, &user_vm86
->regs
.esp
);
263 get_user_ex(seg
, &user_vm86
->regs
.ss
);
264 vm86regs
.pt
.ss
= seg
;
265 get_user_ex(vm86regs
.es
, &user_vm86
->regs
.es
);
266 get_user_ex(vm86regs
.ds
, &user_vm86
->regs
.ds
);
267 get_user_ex(vm86regs
.fs
, &user_vm86
->regs
.fs
);
268 get_user_ex(vm86regs
.gs
, &user_vm86
->regs
.gs
);
270 get_user_ex(vm86
->flags
, &user_vm86
->flags
);
271 get_user_ex(vm86
->screen_bitmap
, &user_vm86
->screen_bitmap
);
272 get_user_ex(vm86
->cpu_type
, &user_vm86
->cpu_type
);
273 } get_user_catch(err
);
277 if (copy_from_user(&vm86
->int_revectored
,
278 &user_vm86
->int_revectored
,
279 sizeof(struct revectored_struct
)))
281 if (copy_from_user(&vm86
->int21_revectored
,
282 &user_vm86
->int21_revectored
,
283 sizeof(struct revectored_struct
)))
286 if (copy_from_user(&vm86
->vm86plus
, &user_vm86
->vm86plus
,
287 sizeof(struct vm86plus_info_struct
)))
289 vm86
->vm86plus
.is_vm86pus
= 1;
291 memset(&vm86
->vm86plus
, 0,
292 sizeof(struct vm86plus_info_struct
));
294 memcpy(&vm86
->regs32
, regs
, sizeof(struct pt_regs
));
295 vm86
->user_vm86
= user_vm86
;
298 * The flags register is also special: we cannot trust that the user
299 * has set it up safely, so this makes sure interrupt etc flags are
300 * inherited from protected mode.
302 VEFLAGS
= vm86regs
.pt
.flags
;
303 vm86regs
.pt
.flags
&= SAFE_MASK
;
304 vm86regs
.pt
.flags
|= regs
->flags
& ~SAFE_MASK
;
305 vm86regs
.pt
.flags
|= X86_VM_MASK
;
307 vm86regs
.pt
.orig_ax
= regs
->orig_ax
;
309 switch (vm86
->cpu_type
) {
311 vm86
->veflags_mask
= 0;
314 vm86
->veflags_mask
= X86_EFLAGS_NT
| X86_EFLAGS_IOPL
;
317 vm86
->veflags_mask
= X86_EFLAGS_AC
| X86_EFLAGS_NT
| X86_EFLAGS_IOPL
;
320 vm86
->veflags_mask
= X86_EFLAGS_ID
| X86_EFLAGS_AC
| X86_EFLAGS_NT
| X86_EFLAGS_IOPL
;
327 vm86
->saved_sp0
= tsk
->thread
.sp0
;
328 lazy_save_gs(vm86
->regs32
.gs
);
330 tss
= &per_cpu(cpu_tss
, get_cpu());
331 /* make room for real-mode segments */
332 tsk
->thread
.sp0
+= 16;
334 tsk
->thread
.sysenter_cs
= 0;
335 load_sp0(tss
, &tsk
->thread
);
338 if (vm86
->flags
& VM86_SCREEN_BITMAP
)
339 mark_screen_rdonly(tsk
->mm
);
341 memcpy((struct kernel_vm86_regs
*)regs
, &vm86regs
, sizeof(vm86regs
));
346 static inline void set_IF(struct kernel_vm86_regs
*regs
)
348 VEFLAGS
|= X86_EFLAGS_VIF
;
351 static inline void clear_IF(struct kernel_vm86_regs
*regs
)
353 VEFLAGS
&= ~X86_EFLAGS_VIF
;
356 static inline void clear_TF(struct kernel_vm86_regs
*regs
)
358 regs
->pt
.flags
&= ~X86_EFLAGS_TF
;
361 static inline void clear_AC(struct kernel_vm86_regs
*regs
)
363 regs
->pt
.flags
&= ~X86_EFLAGS_AC
;
367 * It is correct to call set_IF(regs) from the set_vflags_*
368 * functions. However someone forgot to call clear_IF(regs)
369 * in the opposite case.
370 * After the command sequence CLI PUSHF STI POPF you should
371 * end up with interrupts disabled, but you ended up with
372 * interrupts enabled.
373 * ( I was testing my own changes, but the only bug I
374 * could find was in a function I had not changed. )
378 static inline void set_vflags_long(unsigned long flags
, struct kernel_vm86_regs
*regs
)
380 set_flags(VEFLAGS
, flags
, current
->thread
.vm86
->veflags_mask
);
381 set_flags(regs
->pt
.flags
, flags
, SAFE_MASK
);
382 if (flags
& X86_EFLAGS_IF
)
388 static inline void set_vflags_short(unsigned short flags
, struct kernel_vm86_regs
*regs
)
390 set_flags(VFLAGS
, flags
, current
->thread
.vm86
->veflags_mask
);
391 set_flags(regs
->pt
.flags
, flags
, SAFE_MASK
);
392 if (flags
& X86_EFLAGS_IF
)
398 static inline unsigned long get_vflags(struct kernel_vm86_regs
*regs
)
400 unsigned long flags
= regs
->pt
.flags
& RETURN_MASK
;
402 if (VEFLAGS
& X86_EFLAGS_VIF
)
403 flags
|= X86_EFLAGS_IF
;
404 flags
|= X86_EFLAGS_IOPL
;
405 return flags
| (VEFLAGS
& current
->thread
.vm86
->veflags_mask
);
408 static inline int is_revectored(int nr
, struct revectored_struct
*bitmap
)
410 __asm__
__volatile__("btl %2,%1\n\tsbbl %0,%0"
412 :"m" (*bitmap
), "r" (nr
));
416 #define val_byte(val, n) (((__u8 *)&val)[n])
418 #define pushb(base, ptr, val, err_label) \
422 if (put_user(__val, base + ptr) < 0) \
426 #define pushw(base, ptr, val, err_label) \
430 if (put_user(val_byte(__val, 1), base + ptr) < 0) \
433 if (put_user(val_byte(__val, 0), base + ptr) < 0) \
437 #define pushl(base, ptr, val, err_label) \
441 if (put_user(val_byte(__val, 3), base + ptr) < 0) \
444 if (put_user(val_byte(__val, 2), base + ptr) < 0) \
447 if (put_user(val_byte(__val, 1), base + ptr) < 0) \
450 if (put_user(val_byte(__val, 0), base + ptr) < 0) \
454 #define popb(base, ptr, err_label) \
457 if (get_user(__res, base + ptr) < 0) \
463 #define popw(base, ptr, err_label) \
466 if (get_user(val_byte(__res, 0), base + ptr) < 0) \
469 if (get_user(val_byte(__res, 1), base + ptr) < 0) \
475 #define popl(base, ptr, err_label) \
478 if (get_user(val_byte(__res, 0), base + ptr) < 0) \
481 if (get_user(val_byte(__res, 1), base + ptr) < 0) \
484 if (get_user(val_byte(__res, 2), base + ptr) < 0) \
487 if (get_user(val_byte(__res, 3), base + ptr) < 0) \
493 /* There are so many possible reasons for this function to return
494 * VM86_INTx, so adding another doesn't bother me. We can expect
495 * userspace programs to be able to handle it. (Getting a problem
496 * in userspace is always better than an Oops anyway.) [KD]
498 static void do_int(struct kernel_vm86_regs
*regs
, int i
,
499 unsigned char __user
*ssp
, unsigned short sp
)
501 unsigned long __user
*intr_ptr
;
502 unsigned long segoffs
;
503 struct vm86
*vm86
= current
->thread
.vm86
;
505 if (regs
->pt
.cs
== BIOSSEG
)
507 if (is_revectored(i
, &vm86
->int_revectored
))
509 if (i
== 0x21 && is_revectored(AH(regs
), &vm86
->int21_revectored
))
511 intr_ptr
= (unsigned long __user
*) (i
<< 2);
512 if (get_user(segoffs
, intr_ptr
))
514 if ((segoffs
>> 16) == BIOSSEG
)
516 pushw(ssp
, sp
, get_vflags(regs
), cannot_handle
);
517 pushw(ssp
, sp
, regs
->pt
.cs
, cannot_handle
);
518 pushw(ssp
, sp
, IP(regs
), cannot_handle
);
519 regs
->pt
.cs
= segoffs
>> 16;
521 IP(regs
) = segoffs
& 0xffff;
528 save_v86_state(regs
, VM86_INTx
+ (i
<< 8));
531 int handle_vm86_trap(struct kernel_vm86_regs
*regs
, long error_code
, int trapno
)
533 struct vm86
*vm86
= current
->thread
.vm86
;
535 if (vm86
->vm86plus
.is_vm86pus
) {
536 if ((trapno
== 3) || (trapno
== 1)) {
537 save_v86_state(regs
, VM86_TRAP
+ (trapno
<< 8));
540 do_int(regs
, trapno
, (unsigned char __user
*) (regs
->pt
.ss
<< 4), SP(regs
));
544 return 1; /* we let this handle by the calling routine */
545 current
->thread
.trap_nr
= trapno
;
546 current
->thread
.error_code
= error_code
;
547 force_sig(SIGTRAP
, current
);
551 void handle_vm86_fault(struct kernel_vm86_regs
*regs
, long error_code
)
553 unsigned char opcode
;
554 unsigned char __user
*csp
;
555 unsigned char __user
*ssp
;
556 unsigned short ip
, sp
, orig_flags
;
557 int data32
, pref_done
;
558 struct vm86plus_info_struct
*vmpi
= ¤t
->thread
.vm86
->vm86plus
;
560 #define CHECK_IF_IN_TRAP \
561 if (vmpi->vm86dbg_active && vmpi->vm86dbg_TFpendig) \
562 newflags |= X86_EFLAGS_TF
564 orig_flags
= *(unsigned short *)®s
->pt
.flags
;
566 csp
= (unsigned char __user
*) (regs
->pt
.cs
<< 4);
567 ssp
= (unsigned char __user
*) (regs
->pt
.ss
<< 4);
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;
587 } while (!pref_done
);
594 pushl(ssp
, sp
, get_vflags(regs
), simulate_sigsegv
);
597 pushw(ssp
, sp
, get_vflags(regs
), simulate_sigsegv
);
601 goto vm86_fault_return
;
606 unsigned long newflags
;
608 newflags
= popl(ssp
, sp
, simulate_sigsegv
);
611 newflags
= popw(ssp
, sp
, simulate_sigsegv
);
617 set_vflags_long(newflags
, regs
);
619 set_vflags_short(newflags
, regs
);
626 int intno
= popb(csp
, ip
, simulate_sigsegv
);
628 if (vmpi
->vm86dbg_active
) {
629 if ((1 << (intno
& 7)) & vmpi
->vm86dbg_intxxtab
[intno
>> 3]) {
630 save_v86_state(regs
, VM86_INTx
+ (intno
<< 8));
634 do_int(regs
, intno
, ssp
, sp
);
643 unsigned long newflags
;
645 newip
= popl(ssp
, sp
, simulate_sigsegv
);
646 newcs
= popl(ssp
, sp
, simulate_sigsegv
);
647 newflags
= popl(ssp
, sp
, simulate_sigsegv
);
650 newip
= popw(ssp
, sp
, simulate_sigsegv
);
651 newcs
= popw(ssp
, sp
, simulate_sigsegv
);
652 newflags
= popw(ssp
, sp
, simulate_sigsegv
);
659 set_vflags_long(newflags
, regs
);
661 set_vflags_short(newflags
, regs
);
670 goto vm86_fault_return
;
674 * Damn. This is incorrect: the 'sti' instruction should actually
675 * enable interrupts after the /next/ instruction. Not good.
677 * Probably needs some horsing around with the TF flag. Aiee..
685 save_v86_state(regs
, VM86_UNKNOWN
);
691 if (VEFLAGS
& X86_EFLAGS_VIP
) {
692 save_v86_state(regs
, VM86_STI
);
697 if (vmpi
->force_return_for_pic
&& (VEFLAGS
& (X86_EFLAGS_IF
| X86_EFLAGS_VIF
))) {
698 save_v86_state(regs
, VM86_PICRETURN
);
701 if (orig_flags
& X86_EFLAGS_TF
)
702 handle_vm86_trap(regs
, 0, X86_TRAP_DB
);
706 /* FIXME: After a long discussion with Stas we finally
707 * agreed, that this is wrong. Here we should
708 * really send a SIGSEGV to the user program.
709 * But how do we create the correct context? We
710 * are inside a general protection fault handler
711 * and has just returned from a page fault handler.
712 * The correct context for the signal handler
713 * should be a mixture of the two, but how do we
714 * get the information? [KD]
716 save_v86_state(regs
, VM86_UNKNOWN
);
719 /* ---------------- vm86 special IRQ passing stuff ----------------- */
721 #define VM86_IRQNAME "vm86irq"
723 static struct vm86_irqs
{
724 struct task_struct
*tsk
;
728 static DEFINE_SPINLOCK(irqbits_lock
);
731 #define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \
732 | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \
735 static irqreturn_t
irq_handler(int intno
, void *dev_id
)
740 spin_lock_irqsave(&irqbits_lock
, flags
);
741 irq_bit
= 1 << intno
;
742 if ((irqbits
& irq_bit
) || !vm86_irqs
[intno
].tsk
)
745 if (vm86_irqs
[intno
].sig
)
746 send_sig(vm86_irqs
[intno
].sig
, vm86_irqs
[intno
].tsk
, 1);
748 * IRQ will be re-enabled when user asks for the irq (whether
749 * polling or as a result of the signal)
751 disable_irq_nosync(intno
);
752 spin_unlock_irqrestore(&irqbits_lock
, flags
);
756 spin_unlock_irqrestore(&irqbits_lock
, flags
);
760 static inline void free_vm86_irq(int irqnumber
)
764 free_irq(irqnumber
, NULL
);
765 vm86_irqs
[irqnumber
].tsk
= NULL
;
767 spin_lock_irqsave(&irqbits_lock
, flags
);
768 irqbits
&= ~(1 << irqnumber
);
769 spin_unlock_irqrestore(&irqbits_lock
, flags
);
772 void release_vm86_irqs(struct task_struct
*task
)
775 for (i
= FIRST_VM86_IRQ
; i
<= LAST_VM86_IRQ
; i
++)
776 if (vm86_irqs
[i
].tsk
== task
)
780 static inline int get_and_reset_irq(int irqnumber
)
786 if (invalid_vm86_irq(irqnumber
)) return 0;
787 if (vm86_irqs
[irqnumber
].tsk
!= current
) return 0;
788 spin_lock_irqsave(&irqbits_lock
, flags
);
789 bit
= irqbits
& (1 << irqnumber
);
792 enable_irq(irqnumber
);
796 spin_unlock_irqrestore(&irqbits_lock
, flags
);
801 static int do_vm86_irq_handling(int subfunction
, int irqnumber
)
804 switch (subfunction
) {
805 case VM86_GET_AND_RESET_IRQ
: {
806 return get_and_reset_irq(irqnumber
);
808 case VM86_GET_IRQ_BITS
: {
811 case VM86_REQUEST_IRQ
: {
812 int sig
= irqnumber
>> 8;
813 int irq
= irqnumber
& 255;
814 if (!capable(CAP_SYS_ADMIN
)) return -EPERM
;
815 if (!((1 << sig
) & ALLOWED_SIGS
)) return -EPERM
;
816 if (invalid_vm86_irq(irq
)) return -EPERM
;
817 if (vm86_irqs
[irq
].tsk
) return -EPERM
;
818 ret
= request_irq(irq
, &irq_handler
, 0, VM86_IRQNAME
, NULL
);
820 vm86_irqs
[irq
].sig
= sig
;
821 vm86_irqs
[irq
].tsk
= current
;
824 case VM86_FREE_IRQ
: {
825 if (invalid_vm86_irq(irqnumber
)) return -EPERM
;
826 if (!vm86_irqs
[irqnumber
].tsk
) return 0;
827 if (vm86_irqs
[irqnumber
].tsk
!= current
) return -EPERM
;
828 free_vm86_irq(irqnumber
);