diff options
| -rw-r--r-- | arch/i386/kernel/ioport.c | 7 | ||||
| -rw-r--r-- | arch/i386/kernel/process.c | 6 | ||||
| -rw-r--r-- | include/asm-i386/processor.h | 16 | ||||
| -rw-r--r-- | include/asm-i386/system.h | 4 |
4 files changed, 27 insertions, 6 deletions
diff --git a/arch/i386/kernel/ioport.c b/arch/i386/kernel/ioport.c index 8b25160..f2b3765 100644 --- a/arch/i386/kernel/ioport.c +++ b/arch/i386/kernel/ioport.c @@ -132,6 +132,7 @@ asmlinkage long sys_iopl(unsigned long unused) volatile struct pt_regs * regs = (struct pt_regs *) &unused; unsigned int level = regs->ebx; unsigned int old = (regs->eflags >> 12) & 3; + struct thread_struct *t = ¤t->thread; if (level > 3) return -EINVAL; @@ -140,8 +141,8 @@ asmlinkage long sys_iopl(unsigned long unused) if (!capable(CAP_SYS_RAWIO)) return -EPERM; } - regs->eflags = (regs->eflags &~ 0x3000UL) | (level << 12); - /* Make sure we return the long way (not sysenter) */ - set_thread_flag(TIF_IRET); + t->iopl = level << 12; + regs->eflags = (regs->eflags & ~X86_EFLAGS_IOPL) | t->iopl; + set_iopl_mask(t->iopl); return 0; } diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index 6609978..b45cbf9 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -712,6 +712,12 @@ struct task_struct fastcall * __switch_to(struct task_struct *prev_p, struct tas loadsegment(gs, next->gs); /* + * Restore IOPL if needed. + */ + if (unlikely(prev->iopl != next->iopl)) + set_iopl_mask(next->iopl); + + /* * Now maybe reload the debug registers */ if (unlikely(next->debugreg[7])) { diff --git a/include/asm-i386/processor.h b/include/asm-i386/processor.h index 992224b..37bef8e 100644 --- a/include/asm-i386/processor.h +++ b/include/asm-i386/processor.h @@ -455,6 +455,7 @@ struct thread_struct { unsigned int saved_fs, saved_gs; /* IO permissions */ unsigned long *io_bitmap_ptr; + unsigned long iopl; /* max allowed port in the bitmap, in bytes: */ unsigned long io_bitmap_max; }; @@ -511,6 +512,21 @@ static inline void load_esp0(struct tss_struct *tss, struct thread_struct *threa : /* no output */ \ :"r" (value)) +/* + * Set IOPL bits in EFLAGS from given mask + */ +static inline void set_iopl_mask(unsigned mask) +{ + unsigned int reg; + __asm__ __volatile__ ("pushfl;" + "popl %0;" + "andl %1, %0;" + "orl %2, %0;" + "pushl %0;" + "popfl" + : "=&r" (reg) + : "i" (~X86_EFLAGS_IOPL), "r" (mask)); +} /* Forward declaration, a strange C thing */ struct task_struct; diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h index 37fd2f8..acd5c26 100644 --- a/include/asm-i386/system.h +++ b/include/asm-i386/system.h @@ -14,8 +14,7 @@ extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struc #define switch_to(prev,next,last) do { \ unsigned long esi,edi; \ - asm volatile("pushfl\n\t" \ - "pushl %%ebp\n\t" \ + asm volatile("pushl %%ebp\n\t" \ "movl %%esp,%0\n\t" /* save ESP */ \ "movl %5,%%esp\n\t" /* restore ESP */ \ "movl $1f,%1\n\t" /* save EIP */ \ @@ -23,7 +22,6 @@ extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struc "jmp __switch_to\n" \ "1:\t" \ "popl %%ebp\n\t" \ - "popfl" \ :"=m" (prev->thread.esp),"=m" (prev->thread.eip), \ "=a" (last),"=S" (esi),"=D" (edi) \ :"m" (next->thread.esp),"m" (next->thread.eip), \ |
