]>
git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - arch/x86/kernel/vm86_32.c
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>
48 #include <asm/uaccess.h>
50 #include <asm/tlbflush.h>
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
65 * Let's hope these problems do not actually matter for anything.
69 #define KVM86 ((struct kernel_vm86_struct *)regs)
70 #define VMPI KVM86->vm86plus
74 * 8- and 16-bit register defines..
76 #define AL(regs) (((unsigned char *)&((regs)->pt.ax))[0])
77 #define AH(regs) (((unsigned char *)&((regs)->pt.ax))[1])
78 #define IP(regs) (*(unsigned short *)&((regs)->pt.ip))
79 #define SP(regs) (*(unsigned short *)&((regs)->pt.sp))
82 * virtual flags (16 and 32-bit versions)
84 #define VFLAGS (*(unsigned short *)&(current->thread.v86flags))
85 #define VEFLAGS (current->thread.v86flags)
87 #define set_flags(X, new, mask) \
88 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
90 #define SAFE_MASK (0xDD5)
91 #define RETURN_MASK (0xDFF)
93 struct pt_regs
*save_v86_state(struct kernel_vm86_regs
*regs
)
95 struct tss_struct
*tss
;
97 struct task_struct
*tsk
= current
;
98 struct vm86plus_struct __user
*user
;
102 * This gets called from entry.S with interrupts disabled, but
103 * from process context. Enable interrupts here, before trying
104 * to access user space.
108 if (!tsk
->thread
.vm86_info
) {
109 pr_alert("no vm86_info: BAD\n");
112 set_flags(regs
->pt
.flags
, VEFLAGS
, X86_EFLAGS_VIF
| tsk
->thread
.v86mask
);
113 user
= tsk
->thread
.vm86_info
;
115 if (!access_ok(VERIFY_WRITE
, user
, VMPI
.is_vm86pus
?
116 sizeof(struct vm86plus_struct
) :
117 sizeof(struct vm86_struct
))) {
118 pr_alert("could not access userspace vm86_info\n");
123 put_user_ex(regs
->pt
.bx
, &user
->regs
.ebx
);
124 put_user_ex(regs
->pt
.cx
, &user
->regs
.ecx
);
125 put_user_ex(regs
->pt
.dx
, &user
->regs
.edx
);
126 put_user_ex(regs
->pt
.si
, &user
->regs
.esi
);
127 put_user_ex(regs
->pt
.di
, &user
->regs
.edi
);
128 put_user_ex(regs
->pt
.bp
, &user
->regs
.ebp
);
129 put_user_ex(regs
->pt
.ax
, &user
->regs
.eax
);
130 put_user_ex(regs
->pt
.ip
, &user
->regs
.eip
);
131 put_user_ex(regs
->pt
.cs
, &user
->regs
.cs
);
132 put_user_ex(regs
->pt
.flags
, &user
->regs
.eflags
);
133 put_user_ex(regs
->pt
.sp
, &user
->regs
.esp
);
134 put_user_ex(regs
->pt
.ss
, &user
->regs
.ss
);
135 put_user_ex(regs
->es
, &user
->regs
.es
);
136 put_user_ex(regs
->ds
, &user
->regs
.ds
);
137 put_user_ex(regs
->fs
, &user
->regs
.fs
);
138 put_user_ex(regs
->gs
, &user
->regs
.gs
);
140 put_user_ex(tsk
->thread
.screen_bitmap
, &user
->screen_bitmap
);
141 } put_user_catch(err
);
143 pr_alert("could not access userspace vm86_info\n");
147 tss
= &per_cpu(cpu_tss
, get_cpu());
148 tsk
->thread
.sp0
= tsk
->thread
.saved_sp0
;
149 tsk
->thread
.sysenter_cs
= __KERNEL_CS
;
150 load_sp0(tss
, &tsk
->thread
);
151 tsk
->thread
.saved_sp0
= 0;
156 lazy_load_gs(ret
->gs
);
161 static void mark_screen_rdonly(struct mm_struct
*mm
)
170 down_write(&mm
->mmap_sem
);
171 pgd
= pgd_offset(mm
, 0xA0000);
172 if (pgd_none_or_clear_bad(pgd
))
174 pud
= pud_offset(pgd
, 0xA0000);
175 if (pud_none_or_clear_bad(pud
))
177 pmd
= pmd_offset(pud
, 0xA0000);
178 split_huge_page_pmd_mm(mm
, 0xA0000, pmd
);
179 if (pmd_none_or_clear_bad(pmd
))
181 pte
= pte_offset_map_lock(mm
, pmd
, 0xA0000, &ptl
);
182 for (i
= 0; i
< 32; i
++) {
183 if (pte_present(*pte
))
184 set_pte(pte
, pte_wrprotect(*pte
));
187 pte_unmap_unlock(pte
, ptl
);
189 up_write(&mm
->mmap_sem
);
195 static int do_vm86_irq_handling(int subfunction
, int irqnumber
);
196 static long do_sys_vm86(struct vm86plus_struct __user
*v86
, bool plus
,
197 struct kernel_vm86_struct
*info
);
199 SYSCALL_DEFINE1(vm86old
, struct vm86_struct __user
*, v86
)
201 struct kernel_vm86_struct info
; /* declare this _on top_,
202 * this avoids wasting of stack space.
203 * This remains on the stack until we
204 * return to 32 bit user space.
207 return do_sys_vm86((struct vm86plus_struct __user
*) v86
, false, &info
);
211 SYSCALL_DEFINE2(vm86
, unsigned long, cmd
, unsigned long, arg
)
213 struct kernel_vm86_struct info
; /* declare this _on top_,
214 * this avoids wasting of stack space.
215 * This remains on the stack until we
216 * return to 32 bit user space.
220 case VM86_REQUEST_IRQ
:
222 case VM86_GET_IRQ_BITS
:
223 case VM86_GET_AND_RESET_IRQ
:
224 return do_vm86_irq_handling(cmd
, (int)arg
);
225 case VM86_PLUS_INSTALL_CHECK
:
227 * NOTE: on old vm86 stuff this will return the error
228 * from access_ok(), because the subfunction is
229 * interpreted as (invalid) address to vm86_struct.
230 * So the installation check works.
235 /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */
236 return do_sys_vm86((struct vm86plus_struct __user
*) arg
, true, &info
);
240 static long do_sys_vm86(struct vm86plus_struct __user
*v86
, bool plus
,
241 struct kernel_vm86_struct
*info
)
243 struct tss_struct
*tss
;
244 struct task_struct
*tsk
= current
;
245 unsigned long err
= 0;
247 if (tsk
->thread
.saved_sp0
)
250 if (!access_ok(VERIFY_READ
, v86
, plus
?
251 sizeof(struct vm86_struct
) :
252 sizeof(struct vm86plus_struct
)))
255 memset(info
, 0, sizeof(*info
));
258 get_user_ex(info
->regs
.pt
.bx
, &v86
->regs
.ebx
);
259 get_user_ex(info
->regs
.pt
.cx
, &v86
->regs
.ecx
);
260 get_user_ex(info
->regs
.pt
.dx
, &v86
->regs
.edx
);
261 get_user_ex(info
->regs
.pt
.si
, &v86
->regs
.esi
);
262 get_user_ex(info
->regs
.pt
.di
, &v86
->regs
.edi
);
263 get_user_ex(info
->regs
.pt
.bp
, &v86
->regs
.ebp
);
264 get_user_ex(info
->regs
.pt
.ax
, &v86
->regs
.eax
);
265 get_user_ex(info
->regs
.pt
.ip
, &v86
->regs
.eip
);
266 get_user_ex(seg
, &v86
->regs
.cs
);
267 info
->regs
.pt
.cs
= seg
;
268 get_user_ex(info
->regs
.pt
.flags
, &v86
->regs
.eflags
);
269 get_user_ex(info
->regs
.pt
.sp
, &v86
->regs
.esp
);
270 get_user_ex(seg
, &v86
->regs
.ss
);
271 info
->regs
.pt
.ss
= seg
;
272 get_user_ex(info
->regs
.es
, &v86
->regs
.es
);
273 get_user_ex(info
->regs
.ds
, &v86
->regs
.ds
);
274 get_user_ex(info
->regs
.fs
, &v86
->regs
.fs
);
275 get_user_ex(info
->regs
.gs
, &v86
->regs
.gs
);
277 get_user_ex(info
->flags
, &v86
->flags
);
278 get_user_ex(info
->screen_bitmap
, &v86
->screen_bitmap
);
279 get_user_ex(info
->cpu_type
, &v86
->cpu_type
);
280 } get_user_catch(err
);
284 if (copy_from_user(&info
->int_revectored
, &v86
->int_revectored
,
285 sizeof(struct revectored_struct
)))
287 if (copy_from_user(&info
->int21_revectored
, &v86
->int21_revectored
,
288 sizeof(struct revectored_struct
)))
291 if (copy_from_user(&info
->vm86plus
, &v86
->vm86plus
,
292 sizeof(struct vm86plus_info_struct
)))
294 info
->vm86plus
.is_vm86pus
= 1;
297 info
->regs32
= current_pt_regs();
298 tsk
->thread
.vm86_info
= v86
;
301 * The flags register is also special: we cannot trust that the user
302 * has set it up safely, so this makes sure interrupt etc flags are
303 * inherited from protected mode.
305 VEFLAGS
= info
->regs
.pt
.flags
;
306 info
->regs
.pt
.flags
&= SAFE_MASK
;
307 info
->regs
.pt
.flags
|= info
->regs32
->flags
& ~SAFE_MASK
;
308 info
->regs
.pt
.flags
|= X86_VM_MASK
;
310 info
->regs
.pt
.orig_ax
= info
->regs32
->orig_ax
;
312 switch (info
->cpu_type
) {
314 tsk
->thread
.v86mask
= 0;
317 tsk
->thread
.v86mask
= X86_EFLAGS_NT
| X86_EFLAGS_IOPL
;
320 tsk
->thread
.v86mask
= X86_EFLAGS_AC
| X86_EFLAGS_NT
| X86_EFLAGS_IOPL
;
323 tsk
->thread
.v86mask
= X86_EFLAGS_ID
| X86_EFLAGS_AC
| X86_EFLAGS_NT
| X86_EFLAGS_IOPL
;
328 * Save old state, set default return value (%ax) to 0 (VM86_SIGNAL)
330 info
->regs32
->ax
= VM86_SIGNAL
;
331 tsk
->thread
.saved_sp0
= tsk
->thread
.sp0
;
332 lazy_save_gs(info
->regs32
->gs
);
334 tss
= &per_cpu(cpu_tss
, get_cpu());
335 tsk
->thread
.sp0
= (unsigned long) &info
->VM86_TSS_ESP0
;
337 tsk
->thread
.sysenter_cs
= 0;
338 load_sp0(tss
, &tsk
->thread
);
341 tsk
->thread
.screen_bitmap
= info
->screen_bitmap
;
342 if (info
->flags
& VM86_SCREEN_BITMAP
)
343 mark_screen_rdonly(tsk
->mm
);
345 /*call __audit_syscall_exit since we do not exit via the normal paths */
346 #ifdef CONFIG_AUDITSYSCALL
347 if (unlikely(current
->audit_context
))
348 __audit_syscall_exit(1, 0);
351 __asm__
__volatile__(
354 #ifdef CONFIG_X86_32_LAZY_GS
357 "jmp resume_userspace"
359 :"r" (&info
->regs
), "r" (task_thread_info(tsk
)), "r" (0));
360 unreachable(); /* we never return here */
363 static inline void return_to_32bit(struct kernel_vm86_regs
*regs16
, int retval
)
365 struct pt_regs
*regs32
;
367 regs32
= save_v86_state(regs16
);
369 __asm__
__volatile__("movl %0,%%esp\n\t"
371 "jmp resume_userspace"
372 : : "r" (regs32
), "r" (current_thread_info()));
375 static inline void set_IF(struct kernel_vm86_regs
*regs
)
377 VEFLAGS
|= X86_EFLAGS_VIF
;
378 if (VEFLAGS
& X86_EFLAGS_VIP
)
379 return_to_32bit(regs
, VM86_STI
);
382 static inline void clear_IF(struct kernel_vm86_regs
*regs
)
384 VEFLAGS
&= ~X86_EFLAGS_VIF
;
387 static inline void clear_TF(struct kernel_vm86_regs
*regs
)
389 regs
->pt
.flags
&= ~X86_EFLAGS_TF
;
392 static inline void clear_AC(struct kernel_vm86_regs
*regs
)
394 regs
->pt
.flags
&= ~X86_EFLAGS_AC
;
398 * It is correct to call set_IF(regs) from the set_vflags_*
399 * functions. However someone forgot to call clear_IF(regs)
400 * in the opposite case.
401 * After the command sequence CLI PUSHF STI POPF you should
402 * end up with interrupts disabled, but you ended up with
403 * interrupts enabled.
404 * ( I was testing my own changes, but the only bug I
405 * could find was in a function I had not changed. )
409 static inline void set_vflags_long(unsigned long flags
, struct kernel_vm86_regs
*regs
)
411 set_flags(VEFLAGS
, flags
, current
->thread
.v86mask
);
412 set_flags(regs
->pt
.flags
, flags
, SAFE_MASK
);
413 if (flags
& X86_EFLAGS_IF
)
419 static inline void set_vflags_short(unsigned short flags
, struct kernel_vm86_regs
*regs
)
421 set_flags(VFLAGS
, flags
, current
->thread
.v86mask
);
422 set_flags(regs
->pt
.flags
, flags
, SAFE_MASK
);
423 if (flags
& X86_EFLAGS_IF
)
429 static inline unsigned long get_vflags(struct kernel_vm86_regs
*regs
)
431 unsigned long flags
= regs
->pt
.flags
& RETURN_MASK
;
433 if (VEFLAGS
& X86_EFLAGS_VIF
)
434 flags
|= X86_EFLAGS_IF
;
435 flags
|= X86_EFLAGS_IOPL
;
436 return flags
| (VEFLAGS
& current
->thread
.v86mask
);
439 static inline int is_revectored(int nr
, struct revectored_struct
*bitmap
)
441 __asm__
__volatile__("btl %2,%1\n\tsbbl %0,%0"
443 :"m" (*bitmap
), "r" (nr
));
447 #define val_byte(val, n) (((__u8 *)&val)[n])
449 #define pushb(base, ptr, val, err_label) \
453 if (put_user(__val, base + ptr) < 0) \
457 #define pushw(base, ptr, val, err_label) \
461 if (put_user(val_byte(__val, 1), base + ptr) < 0) \
464 if (put_user(val_byte(__val, 0), base + ptr) < 0) \
468 #define pushl(base, ptr, val, err_label) \
472 if (put_user(val_byte(__val, 3), base + ptr) < 0) \
475 if (put_user(val_byte(__val, 2), base + ptr) < 0) \
478 if (put_user(val_byte(__val, 1), base + ptr) < 0) \
481 if (put_user(val_byte(__val, 0), base + ptr) < 0) \
485 #define popb(base, ptr, err_label) \
488 if (get_user(__res, base + ptr) < 0) \
494 #define popw(base, ptr, err_label) \
497 if (get_user(val_byte(__res, 0), base + ptr) < 0) \
500 if (get_user(val_byte(__res, 1), base + ptr) < 0) \
506 #define popl(base, ptr, err_label) \
509 if (get_user(val_byte(__res, 0), base + ptr) < 0) \
512 if (get_user(val_byte(__res, 1), base + ptr) < 0) \
515 if (get_user(val_byte(__res, 2), base + ptr) < 0) \
518 if (get_user(val_byte(__res, 3), base + ptr) < 0) \
524 /* There are so many possible reasons for this function to return
525 * VM86_INTx, so adding another doesn't bother me. We can expect
526 * userspace programs to be able to handle it. (Getting a problem
527 * in userspace is always better than an Oops anyway.) [KD]
529 static void do_int(struct kernel_vm86_regs
*regs
, int i
,
530 unsigned char __user
*ssp
, unsigned short sp
)
532 unsigned long __user
*intr_ptr
;
533 unsigned long segoffs
;
535 if (regs
->pt
.cs
== BIOSSEG
)
537 if (is_revectored(i
, &KVM86
->int_revectored
))
539 if (i
== 0x21 && is_revectored(AH(regs
), &KVM86
->int21_revectored
))
541 intr_ptr
= (unsigned long __user
*) (i
<< 2);
542 if (get_user(segoffs
, intr_ptr
))
544 if ((segoffs
>> 16) == BIOSSEG
)
546 pushw(ssp
, sp
, get_vflags(regs
), cannot_handle
);
547 pushw(ssp
, sp
, regs
->pt
.cs
, cannot_handle
);
548 pushw(ssp
, sp
, IP(regs
), cannot_handle
);
549 regs
->pt
.cs
= segoffs
>> 16;
551 IP(regs
) = segoffs
& 0xffff;
558 return_to_32bit(regs
, VM86_INTx
+ (i
<< 8));
561 int handle_vm86_trap(struct kernel_vm86_regs
*regs
, long error_code
, int trapno
)
563 if (VMPI
.is_vm86pus
) {
564 if ((trapno
== 3) || (trapno
== 1)) {
565 KVM86
->regs32
->ax
= VM86_TRAP
+ (trapno
<< 8);
566 /* setting this flag forces the code in entry_32.S to
567 the path where we call save_v86_state() and change
568 the stack pointer to KVM86->regs32 */
569 set_thread_flag(TIF_NOTIFY_RESUME
);
572 do_int(regs
, trapno
, (unsigned char __user
*) (regs
->pt
.ss
<< 4), SP(regs
));
576 return 1; /* we let this handle by the calling routine */
577 current
->thread
.trap_nr
= trapno
;
578 current
->thread
.error_code
= error_code
;
579 force_sig(SIGTRAP
, current
);
583 void handle_vm86_fault(struct kernel_vm86_regs
*regs
, long error_code
)
585 unsigned char opcode
;
586 unsigned char __user
*csp
;
587 unsigned char __user
*ssp
;
588 unsigned short ip
, sp
, orig_flags
;
589 int data32
, pref_done
;
591 #define CHECK_IF_IN_TRAP \
592 if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \
593 newflags |= X86_EFLAGS_TF
594 #define VM86_FAULT_RETURN do { \
595 if (VMPI.force_return_for_pic && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) \
596 return_to_32bit(regs, VM86_PICRETURN); \
597 if (orig_flags & X86_EFLAGS_TF) \
598 handle_vm86_trap(regs, 0, 1); \
601 orig_flags
= *(unsigned short *)®s
->pt
.flags
;
603 csp
= (unsigned char __user
*) (regs
->pt
.cs
<< 4);
604 ssp
= (unsigned char __user
*) (regs
->pt
.ss
<< 4);
611 switch (opcode
= popb(csp
, ip
, simulate_sigsegv
)) {
612 case 0x66: /* 32-bit data */ data32
= 1; break;
613 case 0x67: /* 32-bit address */ break;
614 case 0x2e: /* CS */ break;
615 case 0x3e: /* DS */ break;
616 case 0x26: /* ES */ break;
617 case 0x36: /* SS */ break;
618 case 0x65: /* GS */ break;
619 case 0x64: /* FS */ break;
620 case 0xf2: /* repnz */ break;
621 case 0xf3: /* rep */ break;
622 default: pref_done
= 1;
624 } while (!pref_done
);
631 pushl(ssp
, sp
, get_vflags(regs
), simulate_sigsegv
);
634 pushw(ssp
, sp
, get_vflags(regs
), simulate_sigsegv
);
643 unsigned long newflags
;
645 newflags
= popl(ssp
, sp
, simulate_sigsegv
);
648 newflags
= popw(ssp
, sp
, simulate_sigsegv
);
654 set_vflags_long(newflags
, regs
);
656 set_vflags_short(newflags
, regs
);
663 int intno
= popb(csp
, ip
, simulate_sigsegv
);
665 if (VMPI
.vm86dbg_active
) {
666 if ((1 << (intno
& 7)) & VMPI
.vm86dbg_intxxtab
[intno
>> 3])
667 return_to_32bit(regs
, VM86_INTx
+ (intno
<< 8));
669 do_int(regs
, intno
, ssp
, sp
);
678 unsigned long newflags
;
680 newip
= popl(ssp
, sp
, simulate_sigsegv
);
681 newcs
= popl(ssp
, sp
, simulate_sigsegv
);
682 newflags
= popl(ssp
, sp
, simulate_sigsegv
);
685 newip
= popw(ssp
, sp
, simulate_sigsegv
);
686 newcs
= popw(ssp
, sp
, simulate_sigsegv
);
687 newflags
= popw(ssp
, sp
, simulate_sigsegv
);
694 set_vflags_long(newflags
, regs
);
696 set_vflags_short(newflags
, regs
);
709 * Damn. This is incorrect: the 'sti' instruction should actually
710 * enable interrupts after the /next/ instruction. Not good.
712 * Probably needs some horsing around with the TF flag. Aiee..
720 return_to_32bit(regs
, VM86_UNKNOWN
);
726 /* FIXME: After a long discussion with Stas we finally
727 * agreed, that this is wrong. Here we should
728 * really send a SIGSEGV to the user program.
729 * But how do we create the correct context? We
730 * are inside a general protection fault handler
731 * and has just returned from a page fault handler.
732 * The correct context for the signal handler
733 * should be a mixture of the two, but how do we
734 * get the information? [KD]
736 return_to_32bit(regs
, VM86_UNKNOWN
);
739 /* ---------------- vm86 special IRQ passing stuff ----------------- */
741 #define VM86_IRQNAME "vm86irq"
743 static struct vm86_irqs
{
744 struct task_struct
*tsk
;
748 static DEFINE_SPINLOCK(irqbits_lock
);
751 #define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \
752 | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \
755 static irqreturn_t
irq_handler(int intno
, void *dev_id
)
760 spin_lock_irqsave(&irqbits_lock
, flags
);
761 irq_bit
= 1 << intno
;
762 if ((irqbits
& irq_bit
) || !vm86_irqs
[intno
].tsk
)
765 if (vm86_irqs
[intno
].sig
)
766 send_sig(vm86_irqs
[intno
].sig
, vm86_irqs
[intno
].tsk
, 1);
768 * IRQ will be re-enabled when user asks for the irq (whether
769 * polling or as a result of the signal)
771 disable_irq_nosync(intno
);
772 spin_unlock_irqrestore(&irqbits_lock
, flags
);
776 spin_unlock_irqrestore(&irqbits_lock
, flags
);
780 static inline void free_vm86_irq(int irqnumber
)
784 free_irq(irqnumber
, NULL
);
785 vm86_irqs
[irqnumber
].tsk
= NULL
;
787 spin_lock_irqsave(&irqbits_lock
, flags
);
788 irqbits
&= ~(1 << irqnumber
);
789 spin_unlock_irqrestore(&irqbits_lock
, flags
);
792 void release_vm86_irqs(struct task_struct
*task
)
795 for (i
= FIRST_VM86_IRQ
; i
<= LAST_VM86_IRQ
; i
++)
796 if (vm86_irqs
[i
].tsk
== task
)
800 static inline int get_and_reset_irq(int irqnumber
)
806 if (invalid_vm86_irq(irqnumber
)) return 0;
807 if (vm86_irqs
[irqnumber
].tsk
!= current
) return 0;
808 spin_lock_irqsave(&irqbits_lock
, flags
);
809 bit
= irqbits
& (1 << irqnumber
);
812 enable_irq(irqnumber
);
816 spin_unlock_irqrestore(&irqbits_lock
, flags
);
821 static int do_vm86_irq_handling(int subfunction
, int irqnumber
)
824 switch (subfunction
) {
825 case VM86_GET_AND_RESET_IRQ
: {
826 return get_and_reset_irq(irqnumber
);
828 case VM86_GET_IRQ_BITS
: {
831 case VM86_REQUEST_IRQ
: {
832 int sig
= irqnumber
>> 8;
833 int irq
= irqnumber
& 255;
834 if (!capable(CAP_SYS_ADMIN
)) return -EPERM
;
835 if (!((1 << sig
) & ALLOWED_SIGS
)) return -EPERM
;
836 if (invalid_vm86_irq(irq
)) return -EPERM
;
837 if (vm86_irqs
[irq
].tsk
) return -EPERM
;
838 ret
= request_irq(irq
, &irq_handler
, 0, VM86_IRQNAME
, NULL
);
840 vm86_irqs
[irq
].sig
= sig
;
841 vm86_irqs
[irq
].tsk
= current
;
844 case VM86_FREE_IRQ
: {
845 if (invalid_vm86_irq(irqnumber
)) return -EPERM
;
846 if (!vm86_irqs
[irqnumber
].tsk
) return 0;
847 if (vm86_irqs
[irqnumber
].tsk
!= current
) return -EPERM
;
848 free_vm86_irq(irqnumber
);