diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/x86/kernel/vm86_32.c')
| -rw-r--r-- | ANDROID_3.4.5/arch/x86/kernel/vm86_32.c | 849 |
1 files changed, 0 insertions, 849 deletions
diff --git a/ANDROID_3.4.5/arch/x86/kernel/vm86_32.c b/ANDROID_3.4.5/arch/x86/kernel/vm86_32.c deleted file mode 100644 index 255f58ae..00000000 --- a/ANDROID_3.4.5/arch/x86/kernel/vm86_32.c +++ /dev/null @@ -1,849 +0,0 @@ -/* - * Copyright (C) 1994 Linus Torvalds - * - * 29 dec 2001 - Fixed oopses caused by unchecked access to the vm86 - * stack - Manfred Spraul <manfred@colorfullife.com> - * - * 22 mar 2002 - Manfred detected the stackfaults, but didn't handle - * them correctly. Now the emulation will be in a - * consistent state after stackfaults - Kasper Dupont - * <kasperd@daimi.au.dk> - * - * 22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont - * <kasperd@daimi.au.dk> - * - * ?? ??? 2002 - Fixed premature returns from handle_vm86_fault - * caused by Kasper Dupont's changes - Stas Sergeev - * - * 4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes. - * Kasper Dupont <kasperd@daimi.au.dk> - * - * 9 apr 2002 - Changed syntax of macros in handle_vm86_fault. - * Kasper Dupont <kasperd@daimi.au.dk> - * - * 9 apr 2002 - Changed stack access macros to jump to a label - * instead of returning to userspace. This simplifies - * do_int, and is needed by handle_vm6_fault. Kasper - * Dupont <kasperd@daimi.au.dk> - * - */ - -#include <linux/capability.h> -#include <linux/errno.h> -#include <linux/interrupt.h> -#include <linux/sched.h> -#include <linux/kernel.h> -#include <linux/signal.h> -#include <linux/string.h> -#include <linux/mm.h> -#include <linux/smp.h> -#include <linux/highmem.h> -#include <linux/ptrace.h> -#include <linux/audit.h> -#include <linux/stddef.h> - -#include <asm/uaccess.h> -#include <asm/io.h> -#include <asm/tlbflush.h> -#include <asm/irq.h> -#include <asm/syscalls.h> - -/* - * Known problems: - * - * Interrupt handling is not guaranteed: - * - a real x86 will disable all interrupts for one instruction - * after a "mov ss,xx" to make stack handling atomic even without - * the 'lss' instruction. We can't guarantee this in v86 mode, - * as the next instruction might result in a page fault or similar. - * - a real x86 will have interrupts disabled for one instruction - * past the 'sti' that enables them. We don't bother with all the - * details yet. - * - * Let's hope these problems do not actually matter for anything. - */ - - -#define KVM86 ((struct kernel_vm86_struct *)regs) -#define VMPI KVM86->vm86plus - - -/* - * 8- and 16-bit register defines.. - */ -#define AL(regs) (((unsigned char *)&((regs)->pt.ax))[0]) -#define AH(regs) (((unsigned char *)&((regs)->pt.ax))[1]) -#define IP(regs) (*(unsigned short *)&((regs)->pt.ip)) -#define SP(regs) (*(unsigned short *)&((regs)->pt.sp)) - -/* - * virtual flags (16 and 32-bit versions) - */ -#define VFLAGS (*(unsigned short *)&(current->thread.v86flags)) -#define VEFLAGS (current->thread.v86flags) - -#define set_flags(X, new, mask) \ -((X) = ((X) & ~(mask)) | ((new) & (mask))) - -#define SAFE_MASK (0xDD5) -#define RETURN_MASK (0xDFF) - -/* convert kernel_vm86_regs to vm86_regs */ -static int copy_vm86_regs_to_user(struct vm86_regs __user *user, - const struct kernel_vm86_regs *regs) -{ - int ret = 0; - - /* - * kernel_vm86_regs is missing gs, so copy everything up to - * (but not including) orig_eax, and then rest including orig_eax. - */ - ret += copy_to_user(user, regs, offsetof(struct kernel_vm86_regs, pt.orig_ax)); - ret += copy_to_user(&user->orig_eax, ®s->pt.orig_ax, - sizeof(struct kernel_vm86_regs) - - offsetof(struct kernel_vm86_regs, pt.orig_ax)); - - return ret; -} - -/* convert vm86_regs to kernel_vm86_regs */ -static int copy_vm86_regs_from_user(struct kernel_vm86_regs *regs, - const struct vm86_regs __user *user, - unsigned extra) -{ - int ret = 0; - - /* copy ax-fs inclusive */ - ret += copy_from_user(regs, user, offsetof(struct kernel_vm86_regs, pt.orig_ax)); - /* copy orig_ax-__gsh+extra */ - ret += copy_from_user(®s->pt.orig_ax, &user->orig_eax, - sizeof(struct kernel_vm86_regs) - - offsetof(struct kernel_vm86_regs, pt.orig_ax) + - extra); - return ret; -} - -struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) -{ - struct tss_struct *tss; - struct pt_regs *ret; - unsigned long tmp; - - /* - * This gets called from entry.S with interrupts disabled, but - * from process context. Enable interrupts here, before trying - * to access user space. - */ - local_irq_enable(); - - if (!current->thread.vm86_info) { - printk("no vm86_info: BAD\n"); - do_exit(SIGSEGV); - } - set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | current->thread.v86mask); - tmp = copy_vm86_regs_to_user(¤t->thread.vm86_info->regs, regs); - tmp += put_user(current->thread.screen_bitmap, ¤t->thread.vm86_info->screen_bitmap); - if (tmp) { - printk("vm86: could not access userspace vm86_info\n"); - do_exit(SIGSEGV); - } - - tss = &per_cpu(init_tss, get_cpu()); - current->thread.sp0 = current->thread.saved_sp0; - current->thread.sysenter_cs = __KERNEL_CS; - load_sp0(tss, ¤t->thread); - current->thread.saved_sp0 = 0; - put_cpu(); - - ret = KVM86->regs32; - - ret->fs = current->thread.saved_fs; - set_user_gs(ret, current->thread.saved_gs); - - return ret; -} - -static void mark_screen_rdonly(struct mm_struct *mm) -{ - pgd_t *pgd; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - spinlock_t *ptl; - int i; - - down_write(&mm->mmap_sem); - pgd = pgd_offset(mm, 0xA0000); - if (pgd_none_or_clear_bad(pgd)) - goto out; - pud = pud_offset(pgd, 0xA0000); - if (pud_none_or_clear_bad(pud)) - goto out; - pmd = pmd_offset(pud, 0xA0000); - split_huge_page_pmd(mm, pmd); - if (pmd_none_or_clear_bad(pmd)) - goto out; - pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); - for (i = 0; i < 32; i++) { - if (pte_present(*pte)) - set_pte(pte, pte_wrprotect(*pte)); - pte++; - } - pte_unmap_unlock(pte, ptl); -out: - up_write(&mm->mmap_sem); - flush_tlb(); -} - - - -static int do_vm86_irq_handling(int subfunction, int irqnumber); -static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk); - -int sys_vm86old(struct vm86_struct __user *v86, struct pt_regs *regs) -{ - struct kernel_vm86_struct info; /* declare this _on top_, - * this avoids wasting of stack space. - * This remains on the stack until we - * return to 32 bit user space. - */ - struct task_struct *tsk; - int tmp, ret = -EPERM; - - tsk = current; - if (tsk->thread.saved_sp0) - goto out; - tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs, - offsetof(struct kernel_vm86_struct, vm86plus) - - sizeof(info.regs)); - ret = -EFAULT; - if (tmp) - goto out; - memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus); - info.regs32 = regs; - tsk->thread.vm86_info = v86; - do_sys_vm86(&info, tsk); - ret = 0; /* we never return here */ -out: - return ret; -} - - -int sys_vm86(unsigned long cmd, unsigned long arg, struct pt_regs *regs) -{ - struct kernel_vm86_struct info; /* declare this _on top_, - * this avoids wasting of stack space. - * This remains on the stack until we - * return to 32 bit user space. - */ - struct task_struct *tsk; - int tmp, ret; - struct vm86plus_struct __user *v86; - - tsk = current; - switch (cmd) { - case VM86_REQUEST_IRQ: - case VM86_FREE_IRQ: - case VM86_GET_IRQ_BITS: - case VM86_GET_AND_RESET_IRQ: - ret = do_vm86_irq_handling(cmd, (int)arg); - goto out; - case VM86_PLUS_INSTALL_CHECK: - /* - * NOTE: on old vm86 stuff this will return the error - * from access_ok(), because the subfunction is - * interpreted as (invalid) address to vm86_struct. - * So the installation check works. - */ - ret = 0; - goto out; - } - - /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */ - ret = -EPERM; - if (tsk->thread.saved_sp0) - goto out; - v86 = (struct vm86plus_struct __user *)arg; - tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs, - offsetof(struct kernel_vm86_struct, regs32) - - sizeof(info.regs)); - ret = -EFAULT; - if (tmp) - goto out; - info.regs32 = regs; - info.vm86plus.is_vm86pus = 1; - tsk->thread.vm86_info = (struct vm86_struct __user *)v86; - do_sys_vm86(&info, tsk); - ret = 0; /* we never return here */ -out: - return ret; -} - - -static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk) -{ - struct tss_struct *tss; -/* - * make sure the vm86() system call doesn't try to do anything silly - */ - info->regs.pt.ds = 0; - info->regs.pt.es = 0; - info->regs.pt.fs = 0; -#ifndef CONFIG_X86_32_LAZY_GS - info->regs.pt.gs = 0; -#endif - -/* - * The flags register is also special: we cannot trust that the user - * has set it up safely, so this makes sure interrupt etc flags are - * inherited from protected mode. - */ - VEFLAGS = info->regs.pt.flags; - info->regs.pt.flags &= SAFE_MASK; - info->regs.pt.flags |= info->regs32->flags & ~SAFE_MASK; - info->regs.pt.flags |= X86_VM_MASK; - - switch (info->cpu_type) { - case CPU_286: - tsk->thread.v86mask = 0; - break; - case CPU_386: - tsk->thread.v86mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL; - break; - case CPU_486: - tsk->thread.v86mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; - break; - default: - tsk->thread.v86mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; - break; - } - -/* - * Save old state, set default return value (%ax) to 0 (VM86_SIGNAL) - */ - info->regs32->ax = VM86_SIGNAL; - tsk->thread.saved_sp0 = tsk->thread.sp0; - tsk->thread.saved_fs = info->regs32->fs; - tsk->thread.saved_gs = get_user_gs(info->regs32); - - tss = &per_cpu(init_tss, get_cpu()); - tsk->thread.sp0 = (unsigned long) &info->VM86_TSS_ESP0; - if (cpu_has_sep) - tsk->thread.sysenter_cs = 0; - load_sp0(tss, &tsk->thread); - put_cpu(); - - tsk->thread.screen_bitmap = info->screen_bitmap; - if (info->flags & VM86_SCREEN_BITMAP) - mark_screen_rdonly(tsk->mm); - - /*call __audit_syscall_exit since we do not exit via the normal paths */ -#ifdef CONFIG_AUDITSYSCALL - if (unlikely(current->audit_context)) - __audit_syscall_exit(1, 0); -#endif - - __asm__ __volatile__( - "movl %0,%%esp\n\t" - "movl %1,%%ebp\n\t" -#ifdef CONFIG_X86_32_LAZY_GS - "mov %2, %%gs\n\t" -#endif - "jmp resume_userspace" - : /* no outputs */ - :"r" (&info->regs), "r" (task_thread_info(tsk)), "r" (0)); - /* we never return here */ -} - -static inline void return_to_32bit(struct kernel_vm86_regs *regs16, int retval) -{ - struct pt_regs *regs32; - - regs32 = save_v86_state(regs16); - regs32->ax = retval; - __asm__ __volatile__("movl %0,%%esp\n\t" - "movl %1,%%ebp\n\t" - "jmp resume_userspace" - : : "r" (regs32), "r" (current_thread_info())); -} - -static inline void set_IF(struct kernel_vm86_regs *regs) -{ - VEFLAGS |= X86_EFLAGS_VIF; - if (VEFLAGS & X86_EFLAGS_VIP) - return_to_32bit(regs, VM86_STI); -} - -static inline void clear_IF(struct kernel_vm86_regs *regs) -{ - VEFLAGS &= ~X86_EFLAGS_VIF; -} - -static inline void clear_TF(struct kernel_vm86_regs *regs) -{ - regs->pt.flags &= ~X86_EFLAGS_TF; -} - -static inline void clear_AC(struct kernel_vm86_regs *regs) -{ - regs->pt.flags &= ~X86_EFLAGS_AC; -} - -/* - * It is correct to call set_IF(regs) from the set_vflags_* - * functions. However someone forgot to call clear_IF(regs) - * in the opposite case. - * After the command sequence CLI PUSHF STI POPF you should - * end up with interrupts disabled, but you ended up with - * interrupts enabled. - * ( I was testing my own changes, but the only bug I - * could find was in a function I had not changed. ) - * [KD] - */ - -static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs) -{ - set_flags(VEFLAGS, flags, current->thread.v86mask); - set_flags(regs->pt.flags, flags, SAFE_MASK); - if (flags & X86_EFLAGS_IF) - set_IF(regs); - else - clear_IF(regs); -} - -static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs) -{ - set_flags(VFLAGS, flags, current->thread.v86mask); - set_flags(regs->pt.flags, flags, SAFE_MASK); - if (flags & X86_EFLAGS_IF) - set_IF(regs); - else - clear_IF(regs); -} - -static inline unsigned long get_vflags(struct kernel_vm86_regs *regs) -{ - unsigned long flags = regs->pt.flags & RETURN_MASK; - - if (VEFLAGS & X86_EFLAGS_VIF) - flags |= X86_EFLAGS_IF; - flags |= X86_EFLAGS_IOPL; - return flags | (VEFLAGS & current->thread.v86mask); -} - -static inline int is_revectored(int nr, struct revectored_struct *bitmap) -{ - __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0" - :"=r" (nr) - :"m" (*bitmap), "r" (nr)); - return nr; -} - -#define val_byte(val, n) (((__u8 *)&val)[n]) - -#define pushb(base, ptr, val, err_label) \ - do { \ - __u8 __val = val; \ - ptr--; \ - if (put_user(__val, base + ptr) < 0) \ - goto err_label; \ - } while (0) - -#define pushw(base, ptr, val, err_label) \ - do { \ - __u16 __val = val; \ - ptr--; \ - if (put_user(val_byte(__val, 1), base + ptr) < 0) \ - goto err_label; \ - ptr--; \ - if (put_user(val_byte(__val, 0), base + ptr) < 0) \ - goto err_label; \ - } while (0) - -#define pushl(base, ptr, val, err_label) \ - do { \ - __u32 __val = val; \ - ptr--; \ - if (put_user(val_byte(__val, 3), base + ptr) < 0) \ - goto err_label; \ - ptr--; \ - if (put_user(val_byte(__val, 2), base + ptr) < 0) \ - goto err_label; \ - ptr--; \ - if (put_user(val_byte(__val, 1), base + ptr) < 0) \ - goto err_label; \ - ptr--; \ - if (put_user(val_byte(__val, 0), base + ptr) < 0) \ - goto err_label; \ - } while (0) - -#define popb(base, ptr, err_label) \ - ({ \ - __u8 __res; \ - if (get_user(__res, base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - __res; \ - }) - -#define popw(base, ptr, err_label) \ - ({ \ - __u16 __res; \ - if (get_user(val_byte(__res, 0), base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - if (get_user(val_byte(__res, 1), base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - __res; \ - }) - -#define popl(base, ptr, err_label) \ - ({ \ - __u32 __res; \ - if (get_user(val_byte(__res, 0), base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - if (get_user(val_byte(__res, 1), base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - if (get_user(val_byte(__res, 2), base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - if (get_user(val_byte(__res, 3), base + ptr) < 0) \ - goto err_label; \ - ptr++; \ - __res; \ - }) - -/* There are so many possible reasons for this function to return - * VM86_INTx, so adding another doesn't bother me. We can expect - * userspace programs to be able to handle it. (Getting a problem - * in userspace is always better than an Oops anyway.) [KD] - */ -static void do_int(struct kernel_vm86_regs *regs, int i, - unsigned char __user *ssp, unsigned short sp) -{ - unsigned long __user *intr_ptr; - unsigned long segoffs; - - if (regs->pt.cs == BIOSSEG) - goto cannot_handle; - if (is_revectored(i, &KVM86->int_revectored)) - goto cannot_handle; - if (i == 0x21 && is_revectored(AH(regs), &KVM86->int21_revectored)) - goto cannot_handle; - intr_ptr = (unsigned long __user *) (i << 2); - if (get_user(segoffs, intr_ptr)) - goto cannot_handle; - if ((segoffs >> 16) == BIOSSEG) - goto cannot_handle; - pushw(ssp, sp, get_vflags(regs), cannot_handle); - pushw(ssp, sp, regs->pt.cs, cannot_handle); - pushw(ssp, sp, IP(regs), cannot_handle); - regs->pt.cs = segoffs >> 16; - SP(regs) -= 6; - IP(regs) = segoffs & 0xffff; - clear_TF(regs); - clear_IF(regs); - clear_AC(regs); - return; - -cannot_handle: - return_to_32bit(regs, VM86_INTx + (i << 8)); -} - -int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno) -{ - if (VMPI.is_vm86pus) { - if ((trapno == 3) || (trapno == 1)) { - KVM86->regs32->ax = VM86_TRAP + (trapno << 8); - /* setting this flag forces the code in entry_32.S to - call save_v86_state() and change the stack pointer - to KVM86->regs32 */ - set_thread_flag(TIF_IRET); - return 0; - } - do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs)); - return 0; - } - if (trapno != 1) - return 1; /* we let this handle by the calling routine */ - current->thread.trap_nr = trapno; - current->thread.error_code = error_code; - force_sig(SIGTRAP, current); - return 0; -} - -void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) -{ - unsigned char opcode; - unsigned char __user *csp; - unsigned char __user *ssp; - unsigned short ip, sp, orig_flags; - int data32, pref_done; - -#define CHECK_IF_IN_TRAP \ - if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \ - newflags |= X86_EFLAGS_TF -#define VM86_FAULT_RETURN do { \ - if (VMPI.force_return_for_pic && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) \ - return_to_32bit(regs, VM86_PICRETURN); \ - if (orig_flags & X86_EFLAGS_TF) \ - handle_vm86_trap(regs, 0, 1); \ - return; } while (0) - - orig_flags = *(unsigned short *)®s->pt.flags; - - csp = (unsigned char __user *) (regs->pt.cs << 4); - ssp = (unsigned char __user *) (regs->pt.ss << 4); - sp = SP(regs); - ip = IP(regs); - - data32 = 0; - pref_done = 0; - do { - switch (opcode = popb(csp, ip, simulate_sigsegv)) { - case 0x66: /* 32-bit data */ data32 = 1; break; - case 0x67: /* 32-bit address */ break; - case 0x2e: /* CS */ break; - case 0x3e: /* DS */ break; - case 0x26: /* ES */ break; - case 0x36: /* SS */ break; - case 0x65: /* GS */ break; - case 0x64: /* FS */ break; - case 0xf2: /* repnz */ break; - case 0xf3: /* rep */ break; - default: pref_done = 1; - } - } while (!pref_done); - - switch (opcode) { - - /* pushf */ - case 0x9c: - if (data32) { - pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); - SP(regs) -= 4; - } else { - pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); - SP(regs) -= 2; - } - IP(regs) = ip; - VM86_FAULT_RETURN; - - /* popf */ - case 0x9d: - { - unsigned long newflags; - if (data32) { - newflags = popl(ssp, sp, simulate_sigsegv); - SP(regs) += 4; - } else { - newflags = popw(ssp, sp, simulate_sigsegv); - SP(regs) += 2; - } - IP(regs) = ip; - CHECK_IF_IN_TRAP; - if (data32) - set_vflags_long(newflags, regs); - else - set_vflags_short(newflags, regs); - - VM86_FAULT_RETURN; - } - - /* int xx */ - case 0xcd: { - int intno = popb(csp, ip, simulate_sigsegv); - IP(regs) = ip; - if (VMPI.vm86dbg_active) { - if ((1 << (intno & 7)) & VMPI.vm86dbg_intxxtab[intno >> 3]) - return_to_32bit(regs, VM86_INTx + (intno << 8)); - } - do_int(regs, intno, ssp, sp); - return; - } - - /* iret */ - case 0xcf: - { - unsigned long newip; - unsigned long newcs; - unsigned long newflags; - if (data32) { - newip = popl(ssp, sp, simulate_sigsegv); - newcs = popl(ssp, sp, simulate_sigsegv); - newflags = popl(ssp, sp, simulate_sigsegv); - SP(regs) += 12; - } else { - newip = popw(ssp, sp, simulate_sigsegv); - newcs = popw(ssp, sp, simulate_sigsegv); - newflags = popw(ssp, sp, simulate_sigsegv); - SP(regs) += 6; - } - IP(regs) = newip; - regs->pt.cs = newcs; - CHECK_IF_IN_TRAP; - if (data32) { - set_vflags_long(newflags, regs); - } else { - set_vflags_short(newflags, regs); - } - VM86_FAULT_RETURN; - } - - /* cli */ - case 0xfa: - IP(regs) = ip; - clear_IF(regs); - VM86_FAULT_RETURN; - - /* sti */ - /* - * Damn. This is incorrect: the 'sti' instruction should actually - * enable interrupts after the /next/ instruction. Not good. - * - * Probably needs some horsing around with the TF flag. Aiee.. - */ - case 0xfb: - IP(regs) = ip; - set_IF(regs); - VM86_FAULT_RETURN; - - default: - return_to_32bit(regs, VM86_UNKNOWN); - } - - return; - -simulate_sigsegv: - /* FIXME: After a long discussion with Stas we finally - * agreed, that this is wrong. Here we should - * really send a SIGSEGV to the user program. - * But how do we create the correct context? We - * are inside a general protection fault handler - * and has just returned from a page fault handler. - * The correct context for the signal handler - * should be a mixture of the two, but how do we - * get the information? [KD] - */ - return_to_32bit(regs, VM86_UNKNOWN); -} - -/* ---------------- vm86 special IRQ passing stuff ----------------- */ - -#define VM86_IRQNAME "vm86irq" - -static struct vm86_irqs { - struct task_struct *tsk; - int sig; -} vm86_irqs[16]; - -static DEFINE_SPINLOCK(irqbits_lock); -static int irqbits; - -#define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \ - | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ - | (1 << SIGUNUSED)) - -static irqreturn_t irq_handler(int intno, void *dev_id) -{ - int irq_bit; - unsigned long flags; - - spin_lock_irqsave(&irqbits_lock, flags); - irq_bit = 1 << intno; - if ((irqbits & irq_bit) || !vm86_irqs[intno].tsk) - goto out; - irqbits |= irq_bit; - if (vm86_irqs[intno].sig) - send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); - /* - * IRQ will be re-enabled when user asks for the irq (whether - * polling or as a result of the signal) - */ - disable_irq_nosync(intno); - spin_unlock_irqrestore(&irqbits_lock, flags); - return IRQ_HANDLED; - -out: - spin_unlock_irqrestore(&irqbits_lock, flags); - return IRQ_NONE; -} - -static inline void free_vm86_irq(int irqnumber) -{ - unsigned long flags; - - free_irq(irqnumber, NULL); - vm86_irqs[irqnumber].tsk = NULL; - - spin_lock_irqsave(&irqbits_lock, flags); - irqbits &= ~(1 << irqnumber); - spin_unlock_irqrestore(&irqbits_lock, flags); -} - -void release_vm86_irqs(struct task_struct *task) -{ - int i; - for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) - if (vm86_irqs[i].tsk == task) - free_vm86_irq(i); -} - -static inline int get_and_reset_irq(int irqnumber) -{ - int bit; - unsigned long flags; - int ret = 0; - - if (invalid_vm86_irq(irqnumber)) return 0; - if (vm86_irqs[irqnumber].tsk != current) return 0; - spin_lock_irqsave(&irqbits_lock, flags); - bit = irqbits & (1 << irqnumber); - irqbits &= ~bit; - if (bit) { - enable_irq(irqnumber); - ret = 1; - } - - spin_unlock_irqrestore(&irqbits_lock, flags); - return ret; -} - - -static int do_vm86_irq_handling(int subfunction, int irqnumber) -{ - int ret; - switch (subfunction) { - case VM86_GET_AND_RESET_IRQ: { - return get_and_reset_irq(irqnumber); - } - case VM86_GET_IRQ_BITS: { - return irqbits; - } - case VM86_REQUEST_IRQ: { - int sig = irqnumber >> 8; - int irq = irqnumber & 255; - if (!capable(CAP_SYS_ADMIN)) return -EPERM; - if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; - if (invalid_vm86_irq(irq)) return -EPERM; - if (vm86_irqs[irq].tsk) return -EPERM; - ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); - if (ret) return ret; - vm86_irqs[irq].sig = sig; - vm86_irqs[irq].tsk = current; - return irq; - } - case VM86_FREE_IRQ: { - if (invalid_vm86_irq(irqnumber)) return -EPERM; - if (!vm86_irqs[irqnumber].tsk) return 0; - if (vm86_irqs[irqnumber].tsk != current) return -EPERM; - free_vm86_irq(irqnumber); - return 0; - } - } - return -EINVAL; -} - |