More work on x86_64 port of usermode

[tpg/acess2.git] / Kernel / arch / x86_64 / lib.c

diff --git a/Kernel/arch/x86_64/lib.c b/Kernel/arch/x86_64/lib.c
index ba1a618..da9955c 100644 (file)
--- a/Kernel/arch/x86_64/lib.c
+++ b/Kernel/arch/x86_64/lib.c
@@ -3,7 +3,133 @@
 #include <acess.h>
 #include <arch.h>
 
+// === IMPORTS ===
+extern int     GetCPUNum(void);
+extern void    *Proc_GetCurThread(void);
+
 // === CODE ===
+/**
+ * \brief Determine if a short spinlock is locked
+ * \param Lock Lock pointer
+ */
+int IS_LOCKED(struct sShortSpinlock *Lock)
+{
+       return !!Lock->Lock;
+}
+
+/**
+ * \brief Check if the current CPU has the lock
+ * \param Lock Lock pointer
+ */
+int CPU_HAS_LOCK(struct sShortSpinlock *Lock)
+{
+       #if STACKED_LOCKS == 1
+       return Lock->Lock == GetCPUNum() + 1;
+       #elif STACKED_LOCKS == 2
+       return Lock->Lock == Proc_GetCurThread();
+       #else
+       return 0;
+       #endif
+}
+
+/**
+ * \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. As a matter of fact, spend as
+ * little time as possible with this lock held
+ * \note If \a STACKED_LOCKS is set, this type of spinlock can be nested
+ */
+void SHORTLOCK(struct sShortSpinlock *Lock)
+{
+        int    v = 1;
+       #if LOCK_DISABLE_INTS
+        int    IF;
+       #endif
+       #if STACKED_LOCKS == 1
+        int    cpu = GetCPUNum() + 1;
+       #elif STACKED_LOCKS == 2
+       void    *thread = Proc_GetCurThread();
+       #endif
+       
+       #if LOCK_DISABLE_INTS
+       // Save interrupt state and clear interrupts
+       __ASM__ ("pushf;\n\tpop %0" : "=r"(IF));
+       IF &= 0x200;    // AND out all but the interrupt flag
+       #endif
+       
+       #if STACKED_LOCKS == 1
+       if( Lock->Lock == cpu ) {
+               Lock->Depth ++;
+               return ;
+       }
+       #elif STACKED_LOCKS == 2
+       if( Lock->Lock == thread ) {
+               Lock->Depth ++;
+               return ;
+       }
+       #endif
+       
+       // Wait for another CPU to release
+       while(v) {
+               // CMPXCHG:
+               //  If r/m32 == EAX, set ZF and set r/m32 = r32
+               //  Else, clear ZF and set EAX = r/m32
+               #if STACKED_LOCKS == 1
+               __ASM__("lock cmpxchgl %2, (%3)"
+                       : "=a"(v)
+                       : "a"(0), "r"(cpu), "r"(&Lock->Lock)
+                       );
+               #elif STACKED_LOCKS == 2
+               __ASM__("lock cmpxchgq %2, (%3)"
+                       : "=a"(v)
+                       : "a"(0), "r"(thread), "r"(&Lock->Lock)
+                       );
+               #else
+               __ASM__("xchgl %0, (%2)":"=a"(v):"a"(1),"D"(&Lock->Lock));
+               #endif
+               
+               #if LOCK_DISABLE_INTS
+               if( v ) __ASM__("sti"); // Re-enable interrupts
+               #endif
+       }
+       
+       #if LOCK_DISABLE_INTS
+       __ASM__("cli");
+       Lock->IF = IF;
+       #endif
+}
+/**
+ * \brief Release a short lock
+ * \param Lock Lock pointer
+ */
+void SHORTREL(struct sShortSpinlock *Lock)
+{
+       #if STACKED_LOCKS
+       if( Lock->Depth ) {
+               Lock->Depth --;
+               return ;
+       }
+       #endif
+       
+       #if LOCK_DISABLE_INTS
+       // Lock->IF can change anytime once Lock->Lock is zeroed
+       if(Lock->IF) {
+               Lock->Lock = 0;
+               __ASM__ ("sti");
+       }
+       else {
+               Lock->Lock = 0;
+       }
+       #else
+       Lock->Lock = 0;
+       #endif
+}
 
 void outb(Uint16 Port, Uint8 Data)
 {
@@ -150,3 +276,9 @@ void *memset(void *__dest, int __val, size_t __count)
        return __dest;
 }
 
+void *memsetd(void *__dest, Uint32 __val, size_t __count)
+{
+       __asm__ __volatile__ ("rep stosl" : : "D"(__dest),"a"(__val),"c"(__count));
+       return __dest;
+}
+