patch-2.0.28 linux/arch/i386/kernel/vm86.c

• Lines: 494
• Date: Wed Dec 11 16:41:01 1996
• Orig file: v2.0.27/linux/arch/i386/kernel/vm86.c
• Orig date: Wed Apr 3 10:59:32 1996

diff -u --recursive --new-file v2.0.27/linux/arch/i386/kernel/vm86.c linux/arch/i386/kernel/vm86.c
@@ -30,6 +30,11 @@
  * Hopefully 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..
  */
@@ -50,10 +55,9 @@
 #define SAFE_MASK	(0xDD5)
 #define RETURN_MASK	(0xDFF)
 
+
 asmlinkage struct pt_regs * save_v86_state(struct vm86_regs * regs)
 {
-	unsigned long tmp;
-
 	if (!current->tss.vm86_info) {
 		printk("no vm86_info: BAD\n");
 		do_exit(SIGSEGV);
@@ -61,10 +65,9 @@
 	set_flags(regs->eflags, VEFLAGS, VIF_MASK | current->tss.v86mask);
 	memcpy_tofs(&current->tss.vm86_info->regs,regs,sizeof(*regs));
 	put_fs_long(current->tss.screen_bitmap,&current->tss.vm86_info->screen_bitmap);
-	tmp = current->tss.esp0;
 	current->tss.esp0 = current->saved_kernel_stack;
 	current->saved_kernel_stack = 0;
-	return (struct pt_regs *) tmp;
+	return KVM86->regs32;
 }
 
 static void mark_screen_rdonly(struct task_struct * tsk)
@@ -99,67 +102,127 @@
 	flush_tlb();
 }
 
-asmlinkage int sys_vm86(struct vm86_struct * v86)
+
+
+static do_vm86_irq_handling(int subfunction, int irqnumber);
+static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk);
+
+asmlinkage int sys_vm86old(struct vm86_struct * v86)
 {
-	struct vm86_struct info;
-	struct pt_regs * pt_regs = (struct pt_regs *) &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 error;
 
-	if (current->saved_kernel_stack)
+	if (tsk->saved_kernel_stack)
 		return -EPERM;
 	/* v86 must be readable (now) and writable (for save_v86_state) */
 	error = verify_area(VERIFY_WRITE,v86,sizeof(*v86));
 	if (error)
 		return error;
-	memcpy_fromfs(&info,v86,sizeof(info));
+	memcpy_fromfs(&info,v86,sizeof(struct vm86_struct));
+	memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus);
+	info.regs32 = (struct pt_regs *) &v86;
+	tsk->tss.vm86_info = v86;
+	do_sys_vm86(&info, tsk);
+	return 0;	/* we never return here */
+}
+
+
+asmlinkage int sys_vm86(unsigned long subfunction, struct vm86plus_struct * 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 error;
+
+	switch (subfunction) {
+		case VM86_REQUEST_IRQ:
+		case VM86_FREE_IRQ:
+		case VM86_GET_IRQ_BITS:
+		case VM86_GET_AND_RESET_IRQ:
+			return do_vm86_irq_handling(subfunction,(int)v86);
+		case VM86_PLUS_INSTALL_CHECK:
+			/* NOTE: on old vm86 stuff this will return the error
+			   from verify_area(), 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->saved_kernel_stack)
+		return -EPERM;
+	/* v86 must be readable (now) and writable (for save_v86_state) */
+	error = verify_area(VERIFY_WRITE,v86,sizeof(struct vm86plus_struct));
+	if (error)
+		return error;
+	memcpy_fromfs(&info,v86,sizeof(struct vm86plus_struct));
+	info.regs32 = (struct pt_regs *) &subfunction;
+	info.vm86plus.is_vm86pus = 1;
+	tsk->tss.vm86_info = (struct vm86_struct *)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)
+{
 /*
  * make sure the vm86() system call doesn't try to do anything silly
  */
-	info.regs.__null_ds = 0;
-	info.regs.__null_es = 0;
-	info.regs.__null_fs = 0;
-	info.regs.__null_gs = 0;
+	info->regs.__null_ds = 0;
+	info->regs.__null_es = 0;
+	info->regs.__null_fs = 0;
+	info->regs.__null_gs = 0;
 /*
  * The eflags 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.eflags;
-	info.regs.eflags &= SAFE_MASK;
-	info.regs.eflags |= pt_regs->eflags & ~SAFE_MASK;
-	info.regs.eflags |= VM_MASK;
+ 	VEFLAGS = info->regs.eflags;
+	info->regs.eflags &= SAFE_MASK;
+	info->regs.eflags |= info->regs32->eflags & ~SAFE_MASK;
+	info->regs.eflags |= VM_MASK;
 
-	switch (info.cpu_type) {
+	switch (info->cpu_type) {
 		case CPU_286:
-			current->tss.v86mask = 0;
+			tsk->tss.v86mask = 0;
 			break;
 		case CPU_386:
-			current->tss.v86mask = NT_MASK | IOPL_MASK;
+			tsk->tss.v86mask = NT_MASK | IOPL_MASK;
 			break;
 		case CPU_486:
-			current->tss.v86mask = AC_MASK | NT_MASK | IOPL_MASK;
+			tsk->tss.v86mask = AC_MASK | NT_MASK | IOPL_MASK;
 			break;
 		default:
-			current->tss.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
+			tsk->tss.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
 			break;
 	}
 
 /*
  * Save old state, set default return value (%eax) to 0
  */
-	pt_regs->eax = 0;
-	current->saved_kernel_stack = current->tss.esp0;
-	current->tss.esp0 = (unsigned long) pt_regs;
-	current->tss.vm86_info = v86;
-
-	current->tss.screen_bitmap = info.screen_bitmap;
-	if (info.flags & VM86_SCREEN_BITMAP)
-		mark_screen_rdonly(current);
-	__asm__ __volatile__("movl %0,%%esp\n\t"
+	info->regs32->eax = 0;
+	tsk->saved_kernel_stack = tsk->tss.esp0;
+	tsk->tss.esp0 = (unsigned long) &info->VM86_TSS_ESP0;
+
+	tsk->tss.screen_bitmap = info->screen_bitmap;
+	if (info->flags & VM86_SCREEN_BITMAP)
+		mark_screen_rdonly(tsk);
+	__asm__ __volatile__(
+		"movl %0,%%esp\n\t"
 		"jmp ret_from_sys_call"
 		: /* no outputs */
-		:"r" (&info.regs));
-	return 0;
+		:"r" (&info->regs));
+	/* we never return here */
 }
 
 static inline void return_to_32bit(struct vm86_regs * regs16, int retval)
@@ -217,9 +280,7 @@
 
 static inline int is_revectored(int nr, struct revectored_struct * bitmap)
 {
-	if (verify_area(VERIFY_READ, bitmap, 256/8) < 0)
-		return 1;
-	__asm__ __volatile__("btl %2,%%fs:%1\n\tsbbl %0,%0"
+	__asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0"
 		:"=r" (nr)
 		:"m" (*bitmap),"r" (nr));
 	return nr;
@@ -300,26 +361,26 @@
 
 static void do_int(struct vm86_regs *regs, int i, unsigned char * ssp, unsigned long sp)
 {
-	unsigned short *intr_ptr, seg;
+	unsigned long *intr_ptr, segoffs;
 
 	if (regs->cs == BIOSSEG)
 		goto cannot_handle;
-	if (is_revectored(i, &current->tss.vm86_info->int_revectored))
+	if (is_revectored(i, &KVM86->int_revectored))
 		goto cannot_handle;
-	if (i==0x21 && is_revectored(AH(regs),&current->tss.vm86_info->int21_revectored))
+	if (i==0x21 && is_revectored(AH(regs),&KVM86->int21_revectored))
 		goto cannot_handle;
-	intr_ptr = (unsigned short *) (i << 2);
+	intr_ptr = (unsigned long *) (i << 2);
 	if (verify_area(VERIFY_READ, intr_ptr, 4) < 0)
 		goto cannot_handle;
-	seg = get_fs_word(intr_ptr+1);
-	if (seg == BIOSSEG)
+	segoffs = get_fs_long(intr_ptr);
+	if ((segoffs >> 16) == BIOSSEG)
 		goto cannot_handle;
 	pushw(ssp, sp, get_vflags(regs));
 	pushw(ssp, sp, regs->cs);
 	pushw(ssp, sp, IP(regs));
-	regs->cs = seg;
+	regs->cs = segoffs >> 16;
 	SP(regs) -= 6;
-	IP(regs) = get_fs_word(intr_ptr+0);
+	IP(regs) = segoffs & 0xffff;
 	clear_TF(regs);
 	clear_IF(regs);
 	return;
@@ -328,24 +389,40 @@
 	return_to_32bit(regs, VM86_INTx + (i << 8));
 }
 
-void handle_vm86_debug(struct vm86_regs * regs, long error_code)
+
+
+int handle_vm86_trap(struct vm86_regs * regs, long error_code, int trapno)
 {
-#if 0
-	do_int(regs, 1, (unsigned char *) (regs->ss << 4), SP(regs));
-#else
+	if (VMPI.is_vm86pus) {
+		if ( (trapno==3) || (trapno==1) )
+			return_to_32bit(regs, VM86_TRAP + (trapno << 8));
+		do_int(regs, trapno, (unsigned char *) (regs->ss << 4), SP(regs));
+		return 1;
+	}
+	if (trapno !=1)
+		return 0; /* we let this handle by the calling routine */
 	if (current->flags & PF_PTRACED)
 		current->blocked &= ~(1 << (SIGTRAP-1));
 	send_sig(SIGTRAP, current, 1);
-	current->tss.trap_no = 1;
+	current->tss.trap_no = trapno;
 	current->tss.error_code = error_code;
-#endif
+	return 0;
 }
 
+
 void handle_vm86_fault(struct vm86_regs * regs, long error_code)
 {
 	unsigned char *csp, *ssp;
 	unsigned long ip, sp;
 
+#define CHECK_IF_IN_TRAP \
+	if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \
+		pushw(ssp,sp,popw(ssp,sp) | TF_MASK);
+#define VM86_FAULT_RETURN \
+	if (VMPI.force_return_for_pic  && (VEFLAGS & IF_MASK)) \
+		return_to_32bit(regs, VM86_PICRETURN); \
+	return;
+	                                   
 	csp = (unsigned char *) (regs->cs << 4);
 	ssp = (unsigned char *) (regs->ss << 4);
 	sp = SP(regs);
@@ -362,58 +439,70 @@
 			SP(regs) -= 4;
 			IP(regs) += 2;
 			pushl(ssp, sp, get_vflags(regs));
-			return;
+			VM86_FAULT_RETURN;
 
 		/* popfd */
 		case 0x9d:
 			SP(regs) += 4;
 			IP(regs) += 2;
+			CHECK_IF_IN_TRAP
 			set_vflags_long(popl(ssp, sp), regs);
-			return;
+			VM86_FAULT_RETURN;
 
 		/* iretd */
 		case 0xcf:
 			SP(regs) += 12;
 			IP(regs) = (unsigned short)popl(ssp, sp);
 			regs->cs = (unsigned short)popl(ssp, sp);
+			CHECK_IF_IN_TRAP
 			set_vflags_long(popl(ssp, sp), regs);
-			return;
+			VM86_FAULT_RETURN;
+		/* need this to avoid a fallthrough */
+		default:
+			return_to_32bit(regs, VM86_UNKNOWN);
 		}
-		break;
 
 	/* pushf */
 	case 0x9c:
 		SP(regs) -= 2;
 		IP(regs)++;
 		pushw(ssp, sp, get_vflags(regs));
-		return;
+		VM86_FAULT_RETURN;
 
 	/* popf */
 	case 0x9d:
 		SP(regs) += 2;
 		IP(regs)++;
+		CHECK_IF_IN_TRAP
 		set_vflags_short(popw(ssp, sp), regs);
-		return;
+		VM86_FAULT_RETURN;
 
 	/* int xx */
-	case 0xcd:
+	case 0xcd: {
+	        int intno=popb(csp, ip);
 		IP(regs) += 2;
-		do_int(regs, popb(csp, ip), ssp, sp);
+		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:
 		SP(regs) += 6;
 		IP(regs) = popw(ssp, sp);
 		regs->cs = popw(ssp, sp);
+		CHECK_IF_IN_TRAP
 		set_vflags_short(popw(ssp, sp), regs);
-		return;
+		VM86_FAULT_RETURN;
 
 	/* cli */
 	case 0xfa:
 		IP(regs)++;
 		clear_IF(regs);
-		return;
+		VM86_FAULT_RETURN;
 
 	/* sti */
 	/*
@@ -425,11 +514,122 @@
 	case 0xfb:
 		IP(regs)++;
 		set_IF(regs);
+		VM86_FAULT_RETURN;
+
+	default:
+		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] = {{0},}; 
+static int irqbits=0;
+
+#define ALLOWED_SIGS ( 1 /* 0 = don't send a signal */ \
+	| (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO)  | (1 << SIGURG) \
+	| (1 << SIGUNUSED) )
+	
+static void irq_handler(int intno, void *dev_id, struct pt_regs * regs) {
+	int irq_bit;
+	unsigned long flags;
+	
+	save_flags(flags);
+	cli();
+	irq_bit = 1 << intno;
+	if ((irqbits & irq_bit) || ! vm86_irqs[intno].tsk) {
+		restore_flags(flags);
 		return;
 	}
+	irqbits |= irq_bit;
+	if (vm86_irqs[intno].sig)
+		send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1);
+	/* else user will poll for IRQs */
+	restore_flags(flags);
+}
 
-	/*
-	 * We didn't recognize it, let the emulator take care of it..
-	 */
-	return_to_32bit(regs, VM86_UNKNOWN);
+static inline void free_vm86_irq(int irqnumber)
+{
+	free_irq(irqnumber,0);
+	vm86_irqs[irqnumber].tsk = 0;
+	irqbits &= ~(1 << irqnumber);
+}
+
+static inline int task_valid(struct task_struct *tsk)
+{
+	struct task_struct *p;
+
+	for_each_task(p) {
+		if ((p == tsk) && (p->sig)) return 1;
+	}
+	return 0;
 }
+
+static inline void handle_irq_zombies(void)
+{
+	int i;
+	for (i=3; i<16; i++) {
+		if (vm86_irqs[i].tsk) {
+			if (task_valid(vm86_irqs[i].tsk)) continue;
+			free_vm86_irq(i);
+		}
+	}
+}
+
+static inline int get_and_reset_irq(int irqnumber)
+{
+	int bit;
+	unsigned long flags;
+	
+	if ( (irqnumber<3) || (irqnumber>15) ) return 0;
+	if (vm86_irqs[irqnumber].tsk != current) return 0;
+	save_flags(flags);
+	cli();
+	bit = irqbits & (1 << irqnumber);
+	irqbits &= ~bit;
+	restore_flags(flags);
+	return bit;
+}
+
+
+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;
+			handle_irq_zombies();
+			if (!suser()) return -EPERM;
+			if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM;
+			if ( (irq<3) || (irq>15) ) return -EPERM;
+			if (vm86_irqs[irq].tsk) return -EPERM;
+			ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, 0);
+			if (ret) return ret;
+			vm86_irqs[irq].sig = sig;
+			vm86_irqs[irq].tsk = current;
+			return irq;
+		}
+		case  VM86_FREE_IRQ: {
+			handle_irq_zombies();
+			if ( (irqnumber<3) || (irqnumber>15) ) 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;
+}
+