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Commit 9fda6a06 authored by Brian Gerst's avatar Brian Gerst Committed by Ingo Molnar
Browse files

x86/vm86: Move vm86 fields out of 'thread_struct' 



Allocate a separate structure for the vm86 fields.

Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438148483-11932-2-git-send-email-brgerst@gmail.com


[ Build fixes. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e800eb39

arch/x86/include/asm/processor.h

+3 −8
Original line number Diff line number Diff line
@@ -6,8 +6,8 @@ 
/* Forward declaration, a strange C thing */

struct task_struct;

struct mm_struct;

struct vm86;



#include <asm/vm86.h>

#include <asm/math_emu.h>

#include <asm/segment.h>

#include <asm/types.h>
@@ -400,13 +400,9 @@ struct thread_struct { 
	unsigned long		cr2;

	unsigned long		trap_nr;

	unsigned long		error_code;

#ifdef CONFIG_X86_32

#ifdef CONFIG_VM86

	/* Virtual 86 mode info */

	struct vm86plus_struct __user *vm86_info;

	unsigned long		screen_bitmap;

	unsigned long		v86flags;

	unsigned long		v86mask;

	unsigned long		saved_sp0;

	struct vm86		*vm86;

#endif

	/* IO permissions: */

	unsigned long		*io_bitmap_ptr;
@@ -718,7 +714,6 @@ static inline void spin_lock_prefetch(const void *x) 


#define INIT_THREAD  {							  \

	.sp0			= TOP_OF_INIT_STACK,			  \

	.vm86_info		= NULL,					  \

	.sysenter_cs		= __KERNEL_CS,				  \

	.io_bitmap_ptr		= NULL,					  \

}

arch/x86/include/asm/vm86.h

+18 −1
Original line number Diff line number Diff line 
#ifndef _ASM_X86_VM86_H

#define _ASM_X86_VM86_H





#include <asm/ptrace.h>

#include <uapi/asm/vm86.h>
@@ -58,6 +57,14 @@ struct kernel_vm86_struct { 
 */

};



struct vm86 {

	struct vm86plus_struct __user *vm86_info;

	unsigned long screen_bitmap;

	unsigned long v86flags;

	unsigned long v86mask;

	unsigned long saved_sp0;

};



#ifdef CONFIG_VM86



void handle_vm86_fault(struct kernel_vm86_regs *, long);
@@ -67,6 +74,14 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *); 
struct task_struct;

void release_vm86_irqs(struct task_struct *);



#define free_vm86(t) do {				\

	struct thread_struct *__t = (t);		\

	if (__t->vm86 != NULL) {			\

		kfree(__t->vm86);			\

		__t->vm86 = NULL;			\

	}						\

} while (0)



#else



#define handle_vm86_fault(a, b)
@@ -77,6 +92,8 @@ static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c) 
	return 0;

}



#define free_vm86(t) do { } while(0)



#endif /* CONFIG_VM86 */



#endif /* _ASM_X86_VM86_H */

arch/x86/kernel/process.c

+3 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <asm/debugreg.h>

#include <asm/nmi.h>

#include <asm/tlbflush.h>

#include <asm/vm86.h>



/*

 * per-CPU TSS segments. Threads are completely 'soft' on Linux,
@@ -110,6 +111,8 @@ void exit_thread(void) 
		kfree(bp);

	}



	free_vm86(t);



	fpu__drop(fpu);

}

arch/x86/kernel/vm86_32.c

+27 −19
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include <linux/ptrace.h>

#include <linux/audit.h>

#include <linux/stddef.h>

#include <linux/slab.h>



#include <asm/uaccess.h>

#include <asm/io.h>
@@ -81,8 +82,8 @@ 
/*

 * virtual flags (16 and 32-bit versions)

 */

#define VFLAGS	(*(unsigned short *)&(current->thread.v86flags))

#define VEFLAGS	(current->thread.v86flags)

#define VFLAGS	(*(unsigned short *)&(current->thread.vm86->v86flags))

#define VEFLAGS	(current->thread.vm86->v86flags)



#define set_flags(X, new, mask) \

((X) = ((X) & ~(mask)) | ((new) & (mask)))
@@ -96,6 +97,7 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) 
	struct pt_regs *ret;

	struct task_struct *tsk = current;

	struct vm86plus_struct __user *user;

	struct vm86 *vm86 = current->thread.vm86;

	long err = 0;



	/*
@@ -105,12 +107,12 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) 
	 */

	local_irq_enable();



	if (!tsk->thread.vm86_info) {

	if (!vm86 || !vm86->vm86_info) {

		pr_alert("no vm86_info: BAD\n");

		do_exit(SIGSEGV);

	}

	set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | tsk->thread.v86mask);

	user = tsk->thread.vm86_info;

	set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | vm86->v86mask);

	user = vm86->vm86_info;



	if (!access_ok(VERIFY_WRITE, user, VMPI.is_vm86pus ?

		       sizeof(struct vm86plus_struct) :
@@ -137,7 +139,7 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) 
		put_user_ex(regs->fs, &user->regs.fs);

		put_user_ex(regs->gs, &user->regs.gs);



		put_user_ex(tsk->thread.screen_bitmap, &user->screen_bitmap);

		put_user_ex(vm86->screen_bitmap, &user->screen_bitmap);

	} put_user_catch(err);

	if (err) {

		pr_alert("could not access userspace vm86_info\n");
@@ -145,10 +147,10 @@ struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) 
	}



	tss = &per_cpu(cpu_tss, get_cpu());

	tsk->thread.sp0 = tsk->thread.saved_sp0;

	tsk->thread.sp0 = vm86->saved_sp0;

	tsk->thread.sysenter_cs = __KERNEL_CS;

	load_sp0(tss, &tsk->thread);

	tsk->thread.saved_sp0 = 0;

	vm86->saved_sp0 = 0;

	put_cpu();



	ret = KVM86->regs32;
@@ -242,9 +244,15 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 
{

	struct tss_struct *tss;

	struct task_struct *tsk = current;

	struct vm86 *vm86 = tsk->thread.vm86;

	unsigned long err = 0;



	if (tsk->thread.saved_sp0)

	if (!vm86) {

		if (!(vm86 = kzalloc(sizeof(*vm86), GFP_KERNEL)))

			return -ENOMEM;

		tsk->thread.vm86 = vm86;

	}

	if (vm86->saved_sp0)

		return -EPERM;



	if (!access_ok(VERIFY_READ, v86, plus ?
@@ -295,7 +303,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 
	}



	info->regs32 = current_pt_regs();

	tsk->thread.vm86_info = v86;

	vm86->vm86_info = v86;



/*

 * The flags register is also special: we cannot trust that the user
@@ -311,16 +319,16 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 


	switch (info->cpu_type) {

	case CPU_286:

		tsk->thread.v86mask = 0;

		vm86->v86mask = 0;

		break;

	case CPU_386:

		tsk->thread.v86mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL;

		vm86->v86mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL;

		break;

	case CPU_486:

		tsk->thread.v86mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL;

		vm86->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;

		vm86->v86mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL;

		break;

	}
@@ -328,7 +336,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 
 * Save old state, set default return value (%ax) to 0 (VM86_SIGNAL)

 */

	info->regs32->ax = VM86_SIGNAL;

	tsk->thread.saved_sp0 = tsk->thread.sp0;

	vm86->saved_sp0 = tsk->thread.sp0;

	lazy_save_gs(info->regs32->gs);



	tss = &per_cpu(cpu_tss, get_cpu());
@@ -338,7 +346,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *v86, bool plus, 
	load_sp0(tss, &tsk->thread);

	put_cpu();



	tsk->thread.screen_bitmap = info->screen_bitmap;

	vm86->screen_bitmap = info->screen_bitmap;

	if (info->flags & VM86_SCREEN_BITMAP)

		mark_screen_rdonly(tsk->mm);
@@ -408,7 +416,7 @@ static inline void clear_AC(struct kernel_vm86_regs *regs) 


static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs)

{

	set_flags(VEFLAGS, flags, current->thread.v86mask);

	set_flags(VEFLAGS, flags, current->thread.vm86->v86mask);

	set_flags(regs->pt.flags, flags, SAFE_MASK);

	if (flags & X86_EFLAGS_IF)

		set_IF(regs);
@@ -418,7 +426,7 @@ static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs 


static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs)

{

	set_flags(VFLAGS, flags, current->thread.v86mask);

	set_flags(VFLAGS, flags, current->thread.vm86->v86mask);

	set_flags(regs->pt.flags, flags, SAFE_MASK);

	if (flags & X86_EFLAGS_IF)

		set_IF(regs);
@@ -433,7 +441,7 @@ static inline unsigned long get_vflags(struct kernel_vm86_regs *regs) 
	if (VEFLAGS & X86_EFLAGS_VIF)

		flags |= X86_EFLAGS_IF;

	flags |= X86_EFLAGS_IOPL;

	return flags | (VEFLAGS & current->thread.v86mask);

	return flags | (VEFLAGS & current->thread.vm86->v86mask);

}



static inline int is_revectored(int nr, struct revectored_struct *bitmap)

arch/x86/mm/fault.c

+4 −2
Original line number Diff line number Diff line
@@ -301,14 +301,16 @@ static inline void 
check_v8086_mode(struct pt_regs *regs, unsigned long address,

		 struct task_struct *tsk)

{

#ifdef CONFIG_VM86

	unsigned long bit;



	if (!v8086_mode(regs))

	if (!v8086_mode(regs) || !tsk->thread.vm86)

		return;



	bit = (address - 0xA0000) >> PAGE_SHIFT;

	if (bit < 32)

		tsk->thread.screen_bitmap |= 1 << bit;

		tsk->thread.vm86->screen_bitmap |= 1 << bit;

#endif

}



static bool low_pfn(unsigned long pfn)