Changeset 6a27d63 in mainline

Timestamp:

2005-05-11T21:53:09Z (20 years ago)

Author:

Jakub Vana <jakub.vana@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

c884ef1

Parents:

6ba143d

Message:

Finished FPU lazy context switching - first version. I have not tested it and there are many things which must be changed when
it runs first time OK.

Files:

• arch/ia32/include/interrupt.h (modified) (1 diff)
• arch/ia32/src/fpu_context.c (modified) (2 diffs)
• arch/ia32/src/interrupt.c (modified) (1 diff)
• arch/ia32/src/pm.c (modified) (1 diff)
• doc/TODO (modified) (2 diffs)
• include/fpu_context.h (modified) (1 diff)
• include/proc/thread.h (modified) (1 diff)
• src/proc/scheduler.c (modified) (2 diffs)
• src/proc/thread.c (modified) (1 diff)

arch/ia32/include/interrupt.h

@@ -77 +77 @@
 extern void null_interrupt(__u8 n, __u32 stack[]);
 extern void gp_fault(__u8 n, __u32 stack[]);
+extern void nm_fault(__u8 n, __u32 stack[]);
 extern void page_fault(__u8 n, __u32 stack[]);
 extern void syscall(__u8 n, __u32 stack[]);

arch/ia32/src/fpu_context.c

@@ -41 +41 @@
 void fpu_context_restore(fpu_context_t *fctx)
 {
-        if(THREAD==CPU->arch.fpu_owner) reset_TS_flag();
-        else set_TS_flag();
+        if(THREAD==CPU->arch.fpu_owner) {reset_TS_flag(); }
+        else {set_TS_flag(); ((CPU->arch).fpu_owner)->fpu_context_engaged=1;}
 }
 
@@ -48 +48 @@
 void fpu_lazy_context_save(fpu_context_t *fctx)
 {
-/*
-        pushl %eax
-        mov 8(%esp),%eax
-        fxsave (%eax)
-        popl %eax
-        ret
-*/      
+    asm(
+        "mov %0,%%eax;"
+        "fxsave (%%eax);"
+        "ret;"
+        :"=m"(fctx)
+        :
+        :"%eax"
+    );  
 }
 
 void fpu_lazy_context_restore(fpu_context_t *fctx)
 {
-/*
-        pushl %eax
-        mov 8(%esp),%eax
-        fxrstor (%eax)
-        popl %eax
-        ret
-*/      
+    asm(
+        "mov %0,%%eax;"
+        "fxrstor (%%eax);"
+        "ret;"
+        :"=m"(fctx)
+        :
+        :"%eax"
+    );
 }
+
+void fpu_init(void)
+{
+    asm(
+        "fninit;"
+    );
+}
+

arch/ia32/src/interrupt.c

@@ -86 +86 @@
 }
 
+void nm_fault(__u8 n, __u32 stack[])
+{
+
+        if (((CPU->arch).fpu_owner)!=NULL) 
+        {  
+                fpu_lazy_context_save(&(((CPU->arch).fpu_owner)->saved_fpu_context));
+                ((CPU->arch).fpu_owner)->fpu_context_engaged=0; /* Enables migration */
+        }
+        
+        if(THREAD->fpu_context_exists) fpu_lazy_context_restore(&(THREAD->saved_fpu_context));
+        else {fpu_init();THREAD->fpu_context_exists=1;}
+
+        (CPU->arch).fpu_owner=THREAD;
+
+        reset_TS_flag();
+        
+//      panic("#NM fault\n");
+}
+
+
+
 void page_fault(__u8 n, __u32 stack[])
 {

arch/ia32/src/pm.c

@@ -121 +121 @@
         }
         trap_register(13, gp_fault);
+        trap_register( 7, nm_fault);
 }
 

doc/TODO

@@ -12 +12 @@
 + save/restore floating point context on context switch 
   + [ia32] lazy context switch using TS flag
++ [ia32] MMX,SSE1-.. initialization
 + [ia32] review privilege separation
   + zero IOPL in EFLAGS
@@ -19 +20 @@
 + make emulated architectures also work on real hardware
 + bring in support for other architectures (e.g. PowerPC)
+
+

include/fpu_context.h

@@ -11 +11 @@
 extern void fpu_lazy_context_save(fpu_context_t *);
 extern void fpu_lazy_context_restore(fpu_context_t *);
-
+extern void fpu_init(void);
 
 

include/proc/thread.h

@@ -75 +75 @@
         context_t sleep_timeout_context;
         fpu_context_t saved_fpu_context;                       
+        int fpu_context_exists;                
+        int fpu_context_engaged;               /* Defined only if thread doesn't run. It means that fpu context is in CPU 
+                                                that last time executes this thread. This disables migration */          
         
         

src/proc/scheduler.c

@@ -268 +268 @@
                             list_remove(&THREAD->threads_link);
                             spinlock_unlock(&threads_lock);
+
+                            spinlock_lock(&THREAD->cpu->lock);
+                            if(THREAD->cpu->arch.fpu_owner==THREAD) THREAD->cpu->arch.fpu_owner=NULL;
+                            spinlock_unlock(&THREAD->cpu->lock);
+
                             
                             free(THREAD);
@@ -428 +433 @@
                                  * We don't want to steal CPU-wired threads neither threads already stolen.
                                  * The latter prevents threads from migrating between CPU's without ever being run.
-                                 */
+                                 * We don't want to steal threads whose FPU context is still in CPU
+                                 */
                                 spinlock_lock(&t->lock);
-                                if (!(t->flags & (X_WIRED | X_STOLEN))) {
+                                if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) {
                                         /*
                                          * Remove t from r.

src/proc/thread.c

@@ -190 +190 @@
                 t->task = task;
                 
+                t->fpu_context_exists=0;
+                t->fpu_context_engaged=0;
+                
                 /*
                  * Register this thread in the system-wide list.