--- /dev/null
+/*
+ * 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>
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/syscalls.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>
+
+/*
+ * 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) {
+ pr_alert("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) {
+ pr_alert("could not access userspace vm86_info\n");
+ do_exit(SIGSEGV);
+ }
+
+ tss = &per_cpu(cpu_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(mm, 0xA0000, 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);
+
+SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, v86)
+{
+ 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 = current;
+ int tmp;
+
+ if (tsk->thread.saved_sp0)
+ return -EPERM;
+ tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs,
+ offsetof(struct kernel_vm86_struct, vm86plus) -
+ sizeof(info.regs));
+ if (tmp)
+ return -EFAULT;
+ memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus);
+ info.regs32 = current_pt_regs();
+ tsk->thread.vm86_info = v86;
+ do_sys_vm86(&info, tsk);
+ return 0; /* we never return here */
+}
+
+
+SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg)
+{
+ 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;
+ 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:
+ return do_vm86_irq_handling(cmd, (int)arg);
+ 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.
+ */
+ return 0;
+ }
+
+ /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */
+ if (tsk->thread.saved_sp0)
+ return -EPERM;
+ 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));
+ if (tmp)
+ return -EFAULT;
+ info.regs32 = current_pt_regs();
+ info.vm86plus.is_vm86pus = 1;
+ tsk->thread.vm86_info = (struct vm86_struct __user *)v86;
+ do_sys_vm86(&info, tsk);
+ return 0; /* we never return here */
+}
+
+
+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(cpu_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
+ the path where we call save_v86_state() and change
+ the stack pointer to KVM86->regs32 */
+ set_thread_flag(TIF_NOTIFY_RESUME);
+ 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;
+}
+
Code Review / kvmfornfv.git / blobdiff