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-rw-r--r--arch/i386/kernel/ioport.c7
-rw-r--r--arch/i386/kernel/process.c6
-rw-r--r--include/asm-i386/processor.h16
-rw-r--r--include/asm-i386/system.h4
4 files changed, 27 insertions, 6 deletions
diff --git a/arch/i386/kernel/ioport.c b/arch/i386/kernel/ioport.c
index 8b25160393c1..f2b37654777f 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 = &current->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 660997800393..b45cbf93d439 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 992224bff549..37bef8ed7bed 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 37fd2f8c7196..acd5c26b69ba 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), \