From 49d26b6eaa8e970c8cf6e299e6ccba2474191bf5 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Thu, 7 Dec 2006 02:14:03 +0100 Subject: [PATCH] [PATCH] i386: Update sys_vm86 to cope with changed pt_regs and %gs usage sys_vm86 uses a struct kernel_vm86_regs, which is identical to pt_regs, but adds an extra space for all the segment registers. Previously this structure was completely independent, so changes in pt_regs had to be reflected in kernel_vm86_regs. This changes just embeds pt_regs in kernel_vm86_regs, and makes the appropriate changes to vm86.c to deal with the new naming. Also, since %gs is dealt with differently in the kernel, this change adjusts vm86.c to reflect this. While making these changes, I also cleaned up some frankly bizarre code which was added when auditing was added to sys_vm86. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden Cc: Jan Beulich Cc: Andi Kleen Cc: Al Viro Cc: Jason Baron Cc: Chris Wright Signed-off-by: Andrew Morton --- arch/i386/kernel/vm86.c | 121 ++++++++++++++++++++++++---------------- include/asm-i386/vm86.h | 17 +----- 2 files changed, 76 insertions(+), 62 deletions(-) diff --git a/arch/i386/kernel/vm86.c b/arch/i386/kernel/vm86.c index cbcd61d6120..be2f96e67f7 100644 --- a/arch/i386/kernel/vm86.c +++ b/arch/i386/kernel/vm86.c @@ -43,6 +43,7 @@ #include #include #include +#include #include #include @@ -72,10 +73,10 @@ /* * 8- and 16-bit register defines.. */ -#define AL(regs) (((unsigned char *)&((regs)->eax))[0]) -#define AH(regs) (((unsigned char *)&((regs)->eax))[1]) -#define IP(regs) (*(unsigned short *)&((regs)->eip)) -#define SP(regs) (*(unsigned short *)&((regs)->esp)) +#define AL(regs) (((unsigned char *)&((regs)->pt.eax))[0]) +#define AH(regs) (((unsigned char *)&((regs)->pt.eax))[1]) +#define IP(regs) (*(unsigned short *)&((regs)->pt.eip)) +#define SP(regs) (*(unsigned short *)&((regs)->pt.esp)) /* * virtual flags (16 and 32-bit versions) @@ -89,10 +90,37 @@ #define SAFE_MASK (0xDD5) #define RETURN_MASK (0xDFF) -#define VM86_REGS_PART2 orig_eax -#define VM86_REGS_SIZE1 \ - ( (unsigned)( & (((struct kernel_vm86_regs *)0)->VM86_REGS_PART2) ) ) -#define VM86_REGS_SIZE2 (sizeof(struct kernel_vm86_regs) - VM86_REGS_SIZE1) +/* 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 xfs, so copy everything up to + (but not including) xgs, and then rest after xgs. */ + ret += copy_to_user(user, regs, offsetof(struct kernel_vm86_regs, pt.xgs)); + ret += copy_to_user(&user->__null_gs, ®s->pt.xgs, + sizeof(struct kernel_vm86_regs) - + offsetof(struct kernel_vm86_regs, pt.xgs)); + + 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; + + ret += copy_from_user(regs, user, offsetof(struct kernel_vm86_regs, pt.xgs)); + ret += copy_from_user(®s->pt.xgs, &user->__null_gs, + sizeof(struct kernel_vm86_regs) - + offsetof(struct kernel_vm86_regs, pt.xgs) + + extra); + + return ret; +} struct pt_regs * FASTCALL(save_v86_state(struct kernel_vm86_regs * regs)); struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) @@ -112,10 +140,8 @@ struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) printk("no vm86_info: BAD\n"); do_exit(SIGSEGV); } - set_flags(regs->eflags, VEFLAGS, VIF_MASK | current->thread.v86mask); - tmp = copy_to_user(¤t->thread.vm86_info->regs,regs, VM86_REGS_SIZE1); - tmp += copy_to_user(¤t->thread.vm86_info->regs.VM86_REGS_PART2, - ®s->VM86_REGS_PART2, VM86_REGS_SIZE2); + set_flags(regs->pt.eflags, VEFLAGS, VIF_MASK | 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"); @@ -129,9 +155,11 @@ struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) current->thread.saved_esp0 = 0; put_cpu(); - loadsegment(fs, current->thread.saved_fs); - loadsegment(gs, current->thread.saved_gs); ret = KVM86->regs32; + + loadsegment(fs, current->thread.saved_fs); + ret->xgs = current->thread.saved_gs; + return ret; } @@ -183,9 +211,9 @@ asmlinkage int sys_vm86old(struct pt_regs regs) tsk = current; if (tsk->thread.saved_esp0) goto out; - tmp = copy_from_user(&info, v86, VM86_REGS_SIZE1); - tmp += copy_from_user(&info.regs.VM86_REGS_PART2, &v86->regs.VM86_REGS_PART2, - (long)&info.vm86plus - (long)&info.regs.VM86_REGS_PART2); + 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; @@ -233,9 +261,9 @@ asmlinkage int sys_vm86(struct pt_regs regs) if (tsk->thread.saved_esp0) goto out; v86 = (struct vm86plus_struct __user *)regs.ecx; - tmp = copy_from_user(&info, v86, VM86_REGS_SIZE1); - tmp += copy_from_user(&info.regs.VM86_REGS_PART2, &v86->regs.VM86_REGS_PART2, - (long)&info.regs32 - (long)&info.regs.VM86_REGS_PART2); + 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; @@ -252,15 +280,15 @@ out: static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk) { struct tss_struct *tss; - long eax; /* * 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.pt.xds = 0; + info->regs.pt.xes = 0; + info->regs.pt.xgs = 0; -/* we are clearing fs,gs later just before "jmp resume_userspace", - * because starting with Linux 2.1.x they aren't no longer saved/restored +/* we are clearing fs later just before "jmp resume_userspace", + * because it is not saved/restored. */ /* @@ -268,10 +296,10 @@ static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk * 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 |= info->regs32->eflags & ~SAFE_MASK; - info->regs.eflags |= VM_MASK; + VEFLAGS = info->regs.pt.eflags; + info->regs.pt.eflags &= SAFE_MASK; + info->regs.pt.eflags |= info->regs32->eflags & ~SAFE_MASK; + info->regs.pt.eflags |= VM_MASK; switch (info->cpu_type) { case CPU_286: @@ -294,7 +322,7 @@ static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk info->regs32->eax = 0; tsk->thread.saved_esp0 = tsk->thread.esp0; savesegment(fs, tsk->thread.saved_fs); - savesegment(gs, tsk->thread.saved_gs); + tsk->thread.saved_gs = info->regs32->xgs; tss = &per_cpu(init_tss, get_cpu()); tsk->thread.esp0 = (unsigned long) &info->VM86_TSS_ESP0; @@ -306,19 +334,18 @@ static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk tsk->thread.screen_bitmap = info->screen_bitmap; if (info->flags & VM86_SCREEN_BITMAP) mark_screen_rdonly(tsk->mm); - __asm__ __volatile__("xorl %eax,%eax; movl %eax,%fs; movl %eax,%gs\n\t"); - __asm__ __volatile__("movl %%eax, %0\n" :"=r"(eax)); /*call audit_syscall_exit since we do not exit via the normal paths */ if (unlikely(current->audit_context)) - audit_syscall_exit(AUDITSC_RESULT(eax), eax); + audit_syscall_exit(AUDITSC_RESULT(0), 0); __asm__ __volatile__( "movl %0,%%esp\n\t" "movl %1,%%ebp\n\t" + "mov %2, %%fs\n\t" "jmp resume_userspace" : /* no outputs */ - :"r" (&info->regs), "r" (task_thread_info(tsk))); + :"r" (&info->regs), "r" (task_thread_info(tsk)), "r" (0)); /* we never return here */ } @@ -348,12 +375,12 @@ static inline void clear_IF(struct kernel_vm86_regs * regs) static inline void clear_TF(struct kernel_vm86_regs * regs) { - regs->eflags &= ~TF_MASK; + regs->pt.eflags &= ~TF_MASK; } static inline void clear_AC(struct kernel_vm86_regs * regs) { - regs->eflags &= ~AC_MASK; + regs->pt.eflags &= ~AC_MASK; } /* It is correct to call set_IF(regs) from the set_vflags_* @@ -370,7 +397,7 @@ static inline void clear_AC(struct kernel_vm86_regs * regs) static inline void set_vflags_long(unsigned long eflags, struct kernel_vm86_regs * regs) { set_flags(VEFLAGS, eflags, current->thread.v86mask); - set_flags(regs->eflags, eflags, SAFE_MASK); + set_flags(regs->pt.eflags, eflags, SAFE_MASK); if (eflags & IF_MASK) set_IF(regs); else @@ -380,7 +407,7 @@ static inline void set_vflags_long(unsigned long eflags, 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(regs->eflags, flags, SAFE_MASK); + set_flags(regs->pt.eflags, flags, SAFE_MASK); if (flags & IF_MASK) set_IF(regs); else @@ -389,7 +416,7 @@ static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_reg static inline unsigned long get_vflags(struct kernel_vm86_regs * regs) { - unsigned long flags = regs->eflags & RETURN_MASK; + unsigned long flags = regs->pt.eflags & RETURN_MASK; if (VEFLAGS & VIF_MASK) flags |= IF_MASK; @@ -493,7 +520,7 @@ static void do_int(struct kernel_vm86_regs *regs, int i, unsigned long __user *intr_ptr; unsigned long segoffs; - if (regs->cs == BIOSSEG) + if (regs->pt.xcs == BIOSSEG) goto cannot_handle; if (is_revectored(i, &KVM86->int_revectored)) goto cannot_handle; @@ -505,9 +532,9 @@ static void do_int(struct kernel_vm86_regs *regs, int i, if ((segoffs >> 16) == BIOSSEG) goto cannot_handle; pushw(ssp, sp, get_vflags(regs), cannot_handle); - pushw(ssp, sp, regs->cs, cannot_handle); + pushw(ssp, sp, regs->pt.xcs, cannot_handle); pushw(ssp, sp, IP(regs), cannot_handle); - regs->cs = segoffs >> 16; + regs->pt.xcs = segoffs >> 16; SP(regs) -= 6; IP(regs) = segoffs & 0xffff; clear_TF(regs); @@ -524,7 +551,7 @@ int handle_vm86_trap(struct kernel_vm86_regs * regs, long error_code, int trapno if (VMPI.is_vm86pus) { if ( (trapno==3) || (trapno==1) ) return_to_32bit(regs, VM86_TRAP + (trapno << 8)); - do_int(regs, trapno, (unsigned char __user *) (regs->ss << 4), SP(regs)); + do_int(regs, trapno, (unsigned char __user *) (regs->pt.xss << 4), SP(regs)); return 0; } if (trapno !=1) @@ -560,10 +587,10 @@ void handle_vm86_fault(struct kernel_vm86_regs * regs, long error_code) handle_vm86_trap(regs, 0, 1); \ return; } while (0) - orig_flags = *(unsigned short *)®s->eflags; + orig_flags = *(unsigned short *)®s->pt.eflags; - csp = (unsigned char __user *) (regs->cs << 4); - ssp = (unsigned char __user *) (regs->ss << 4); + csp = (unsigned char __user *) (regs->pt.xcs << 4); + ssp = (unsigned char __user *) (regs->pt.xss << 4); sp = SP(regs); ip = IP(regs); @@ -650,7 +677,7 @@ void handle_vm86_fault(struct kernel_vm86_regs * regs, long error_code) SP(regs) += 6; } IP(regs) = newip; - regs->cs = newcs; + regs->pt.xcs = newcs; CHECK_IF_IN_TRAP; if (data32) { set_vflags_long(newflags, regs); diff --git a/include/asm-i386/vm86.h b/include/asm-i386/vm86.h index 952fd695738..a5edf517b99 100644 --- a/include/asm-i386/vm86.h +++ b/include/asm-i386/vm86.h @@ -145,26 +145,13 @@ struct vm86plus_struct { * at the end of the structure. Look at ptrace.h to see the "normal" * setup. For user space layout see 'struct vm86_regs' above. */ +#include struct kernel_vm86_regs { /* * normal regs, with special meaning for the segment descriptors.. */ - long ebx; - long ecx; - long edx; - long esi; - long edi; - long ebp; - long eax; - long __null_ds; - long __null_es; - long orig_eax; - long eip; - unsigned short cs, __csh; - long eflags; - long esp; - unsigned short ss, __ssh; + struct pt_regs pt; /* * these are specific to v86 mode: */ -- 2.20.1