x86: save/restore eflags in context switch

[linux-2.6.git] / include / asm-i386 / system.h

diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h
index 19cc79c9a35db68f4fbe1e673b61238a2613e78b..098bcee94e389a615b3b2327fa2be03f117c28c3 100644 (file)
--- a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -1,7 +1,6 @@
 #ifndef __ASM_SYSTEM_H
 #define __ASM_SYSTEM_H
 
-#include <linux/config.h>
 #include <linux/kernel.h>
 #include <asm/segment.h>
 #include <asm/cpufeature.h>
@@ -12,9 +11,14 @@
 struct task_struct;    /* one of the stranger aspects of C forward declarations.. */
 extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));
 
+/*
+ * Saving eflags is important. It switches not only IOPL between tasks,
+ * it also protects other tasks from NT leaking through sysenter etc.
+ */
 #define switch_to(prev,next,last) do {                                 \
        unsigned long esi,edi;                                          \
-       asm volatile("pushl %%ebp\n\t"                                  \
+       asm volatile("pushfl\n\t"               /* Save flags */        \
+                    "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 */          \
@@ -22,6 +26,7 @@ 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),    \
@@ -83,10 +88,6 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
 #define savesegment(seg, value) \
        asm volatile("mov %%" #seg ",%0":"=rm" (value))
 
-/*
- * Clear and set 'TS' bit respectively
- */
-#define clts() __asm__ __volatile__ ("clts")
 #define read_cr0() ({ \
        unsigned int __dummy; \
        __asm__ __volatile__( \
@@ -95,7 +96,7 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
        __dummy; \
 })
 #define write_cr0(x) \
-       __asm__ __volatile__("movl %0,%%cr0": :"r" (x));
+       __asm__ __volatile__("movl %0,%%cr0": :"r" (x))
 
 #define read_cr2() ({ \
        unsigned int __dummy; \
@@ -105,7 +106,7 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
        __dummy; \
 })
 #define write_cr2(x) \
-       __asm__ __volatile__("movl %0,%%cr2": :"r" (x));
+       __asm__ __volatile__("movl %0,%%cr2": :"r" (x))
 
 #define read_cr3() ({ \
        unsigned int __dummy; \
@@ -115,7 +116,7 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
        __dummy; \
 })
 #define write_cr3(x) \
-       __asm__ __volatile__("movl %0,%%cr3": :"r" (x));
+       __asm__ __volatile__("movl %0,%%cr3": :"r" (x))
 
 #define read_cr4() ({ \
        unsigned int __dummy; \
@@ -124,7 +125,6 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
                :"=r" (__dummy)); \
        __dummy; \
 })
-
 #define read_cr4_safe() ({                           \
        unsigned int __dummy;                         \
        /* This could fault if %cr4 does not exist */ \
@@ -136,15 +136,19 @@ __asm__ __volatile__ ("movw %%dx,%1\n\t" \
                : "=r" (__dummy): "0" (0));           \
        __dummy;                                      \
 })
-
 #define write_cr4(x) \
-       __asm__ __volatile__("movl %0,%%cr4": :"r" (x));
+       __asm__ __volatile__("movl %0,%%cr4": :"r" (x))
+
+/*
+ * Clear and set 'TS' bit respectively
+ */
+#define clts() __asm__ __volatile__ ("clts")
 #define stts() write_cr0(8 | read_cr0())
 
 #endif /* __KERNEL__ */
 
 #define wbinvd() \
-       __asm__ __volatile__ ("wbinvd": : :"memory");
+       __asm__ __volatile__ ("wbinvd": : :"memory")
 
 static inline unsigned long get_limit(unsigned long segment)
 {
@@ -428,7 +432,7 @@ static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long l
  * does not enforce ordering, since there is no data dependency between
  * the read of "a" and the read of "b".  Therefore, on some CPUs, such
  * as Alpha, "y" could be set to 3 and "x" to 0.  Use rmb()
- * in cases like thiswhere there are no data dependencies.
+ * in cases like this where there are no data dependencies.
  **/
 
 #define read_barrier_depends() do { } while(0)
@@ -455,27 +459,7 @@ static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long l
 #define set_mb(var, value) do { var = value; barrier(); } while (0)
 #endif
 
-#define set_wmb(var, value) do { var = value; wmb(); } while (0)
-
-/* interrupt control.. */
-#define local_save_flags(x)    do { typecheck(unsigned long,x); __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */); } while (0)
-#define local_irq_restore(x)   do { typecheck(unsigned long,x); __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc"); } while (0)
-#define local_irq_disable()    __asm__ __volatile__("cli": : :"memory")
-#define local_irq_enable()     __asm__ __volatile__("sti": : :"memory")
-/* used in the idle loop; sti takes one instruction cycle to complete */
-#define safe_halt()            __asm__ __volatile__("sti; hlt": : :"memory")
-/* used when interrupts are already enabled or to shutdown the processor */
-#define halt()                 __asm__ __volatile__("hlt": : :"memory")
-
-#define irqs_disabled()                        \
-({                                     \
-       unsigned long flags;            \
-       local_save_flags(flags);        \
-       !(flags & (1<<9));              \
-})
-
-/* For spinlocks etc */
-#define local_irq_save(x)      __asm__ __volatile__("pushfl ; popl %0 ; cli":"=g" (x): /* no input */ :"memory")
+#include <linux/irqflags.h>
 
 /*
  * disable hlt during certain critical i/o operations