Fixed Proc_ReturnToUser's dependence on the structure of tThread

[tpg/acess2.git] / Kernel / arch / x86 / include / arch.h

diff --git a/Kernel/arch/x86/include/arch.h b/Kernel/arch/x86/include/arch.h
index 7735568..eff85fc 100644 (file)
--- a/Kernel/arch/x86/include/arch.h
+++ b/Kernel/arch/x86/include/arch.h
@@ -29,44 +29,71 @@
 
 #define __ASM__        __asm__ __volatile__
 
-// === MACROS ===
-typedef volatile int   tSpinlock;
-#define IS_LOCKED(lockptr)     (!!(*(tSpinlock*)lockptr))
+// === Spinlocks ===
 /**
- * \brief Inter-Process interrupt (does a Yield)
+ * \brief Short Spinlock structure
  */
-#define LOCK(lockptr)  do {\
-       int v=1;\
-       while(v) {\
-               __ASM__("xchgl %%eax, (%%edi)":"=a"(v):"a"(1),"D"(lockptr));\
-               if(v) Threads_Yield();\
-       }\
-}while(0)
+struct sShortSpinlock {
+       volatile int    Lock;   //!< Lock value
+        int    IF;     //!< Interrupt state on call to SHORTLOCK
+};
 /**
- * \brief Tight spinlock (does a HLT)
+ * \brief Determine if a short spinlock is locked
+ * \param Lock Lock pointer
  */
-#define TIGHTLOCK(lockptr)     do{\
-       int v=1;\
-       while(v) {\
-               __ASM__("xchgl %%eax,(%%edi)":"=a"(v):"a"(1),"D"(lockptr));\
-               if(v) __ASM__("hlt");\
-       }\
-}while(0)
+static inline int IS_LOCKED(struct sShortSpinlock *Lock) {
+       return !!Lock->Lock;
+}
 /**
- * \brief Very Tight spinlock (short inter-cpu lock)
+ * \brief Acquire a Short Spinlock
+ * \param Lock Lock pointer
+ * 
+ * This type of mutex should only be used for very short sections of code,
+ * or in places where a Mutex_* would be overkill, such as appending
+ * an element to linked list (usually two assignement lines in C)
+ * 
+ * \note This type of lock halts interrupts, so ensure that no timing
+ * functions are called while it is held.
  */
-#define VTIGHTLOCK(lockptr)    do{\
-       int v=1;\
-       while(v)__ASM__("xchgl %%eax,(%%edi)":"=a"(v):"a"(1),"D"(lockptr));\
-}while(0)
+static inline void SHORTLOCK(struct sShortSpinlock *Lock) {
+        int    v = 1;
+        int    IF;
+       // int  cpu = GetCPUNum() + 1;
+       
+       // Save interrupt state and clear interrupts
+       __ASM__ ("pushf;\n\tcli;\n\tpop %%eax" : "=a"(IF));
+       IF &= 0x200;
+       
+       // Wait for another CPU to release
+       while(v)
+               __ASM__("xchgl %%eax, (%%edi)":"=a"(v):"a"(1),"D"(&Lock->Lock));
+       
+       Lock->IF = IF;
+}
 /**
- * \brief Release a held spinlock
+ * \brief Release a short lock
+ * \param Lock Lock pointer
  */
-#define        RELEASE(lockptr)        __ASM__("lock andl $0, (%%edi)"::"D"(lockptr));
+static inline void SHORTREL(struct sShortSpinlock *Lock) {
+       // Lock->IF can change anytime once Lock->Lock is zeroed
+       if(Lock->IF) {
+               Lock->Lock = 0;
+               __ASM__ ("sti");
+       }
+       else {
+               Lock->Lock = 0;
+       }
+}
+
+// === MACROS ===
 /**
  * \brief Halt the CPU
  */
 #define        HALT()  __asm__ __volatile__ ("hlt")
+/**
+ * \brief Fire a magic breakpoint (bochs)
+ */
+#define        MAGIC_BREAK()   __asm__ __volatile__ ("xchg %bx, %bx")
 
 // === TYPES ===
 typedef unsigned int   Uint;   // Unsigned machine native integer