Unborking some threading code

[tpg/acess2.git] / Kernel / arch / x86_64 / include / arch.h

diff --git a/Kernel/arch/x86_64/include/arch.h b/Kernel/arch/x86_64/include/arch.h
index d419234..6b75a7d 100644 (file)
--- a/Kernel/arch/x86_64/include/arch.h
+++ b/Kernel/arch/x86_64/include/arch.h
@@ -35,17 +35,17 @@ typedef Uint64      tVAddr;
 
 typedef Uint64 size_t;
 
-typedef volatile int    tSpinlock;
-#define IS_LOCKED(lockptr)      (!!(*(tSpinlock*)lockptr))
-#define _LOCK(lockptr,action)   do {int v=1;\
-       while(v)\
-       __asm__ __volatile__("lock xchgl %0, (%2)":"=r"(v):"r"(1),"r"(lockptr));\
-       if(v)   action;\
-       }while(0)
-#define TIGHTLOCK(lockptr)   _LOCK(lockptr, __asm__ __volatile__ ("hlt"));
-#define LOCK(lockptr)   _LOCK(lockptr, Threads_Yield());
-#define RELEASE(lockptr)       __asm__ __volatile__("lock andl $0, (%0)"::"r"(lockptr));
-#define HALT()  __asm__ __volatile__ ("hlt")
+#define __ASM__        __asm__ __volatile__
+
+// === MACROS ===
+/**
+ * \brief Halt the CPU
+ */
+#define        HALT()  __asm__ __volatile__ ("hlt")
+/**
+ * \brief Fire a magic breakpoint (bochs)
+ */
+#define        MAGIC_BREAK()   __asm__ __volatile__ ("xchg %bx, %bx")
 
 // Systemcall Registers
 // TODO: Fix this structure
@@ -71,5 +71,57 @@ typedef struct sSyscallRegs
        Uint    Resvd5[1];      // SS   
 }      tSyscallRegs;
 
+/**
+ * \brief Short Spinlock structure
+ */
+struct sShortSpinlock {
+       volatile int    Lock;   //!< Lock value
+        int    IF;     //!< Interrupt state on call to SHORTLOCK
+};
+/**
+ * \brief Determine if a short spinlock is locked
+ * \param Lock Lock pointer
+ */
+static inline int IS_LOCKED(struct sShortSpinlock *Lock) {
+       return !!Lock->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.
+ */
+static inline void SHORTLOCK(struct sShortSpinlock *Lock) {
+        int    v = 1;
+       
+       // Save interrupt state
+       __ASM__ ("pushf;\n\tpop %%rax" : "=a"(Lock->IF));
+       Lock->IF &= 0x200;
+       
+       // Stop interrupts
+       __ASM__ ("cli");
+       
+       // Wait for another CPU to release
+       while(v)
+               __ASM__("xchgl %%eax, (%%rdi)":"=a"(v):"a"(1),"D"(&Lock->Lock));
+}
+/**
+ * \brief Release a short lock
+ * \param Lock Lock pointer
+ */
+static inline void SHORTREL(struct sShortSpinlock *Lock) {
+       Lock->Lock = 0;
+       #if 0   // Which is faster?, meh the test is simpler
+       __ASM__ ("pushf;\n\tor %0, (%%rsp);\n\tpopf" : : "a"(Lock->IF));
+       #else
+       if(Lock->IF)    __ASM__ ("sti");
+       #endif
+}
+
 #endif