KSE Milestone 2

Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha

1 files changed, 43 insertions, 35 deletions

diff --git a/sys/i386/i386/swtch.s b/sys/i386/i386/swtch.s
index 0f2f7a8..075aa36 100644
--- a/sys/i386/i386/swtch.s
+++ b/sys/i386/i386/swtch.s
@@ -77,17 +77,17 @@ ENTRY(cpu_throw)
 ENTRY(cpu_switch)
 	
 	/* switch to new process. first, save context as needed */
-	movl	PCPU(CURPROC),%ecx
+	movl	PCPU(CURTHREAD),%ecx
 
 	/* if no process to save, don't bother */
 	testl	%ecx,%ecx
 	jz	sw1
-
-	movl	P_VMSPACE(%ecx), %edx
+	movl	TD_PROC(%ecx), %eax
+	movl	P_VMSPACE(%eax), %edx
 	movl	PCPU(CPUID), %eax
 	btrl	%eax, VM_PMAP+PM_ACTIVE(%edx)
 
-	movl	P_ADDR(%ecx),%edx
+	movl	TD_PCB(%ecx),%edx
 
 	movl	(%esp),%eax			/* Hardware registers */
 	movl	%eax,PCB_EIP(%edx)
@@ -124,7 +124,7 @@ ENTRY(cpu_switch)
 
 #ifdef DEV_NPX
 	/* have we used fp, and need a save? */
-	cmpl	%ecx,PCPU(NPXPROC)
+	cmpl	%ecx,PCPU(NPXTHREAD)
 	jne	1f
 	addl	$PCB_SAVEFPU,%edx		/* h/w bugs make saving complicated */
 	pushl	%edx
@@ -133,7 +133,11 @@ ENTRY(cpu_switch)
 1:
 #endif	/* DEV_NPX */
 
+/*##########################################################################*/
+/*##########################################################################*/
+/*##########################################################################*/
 	/* save is done, now choose a new process */
+	/* But still trashing space above the old "Top Of Stack".. */
 sw1:
 
 #ifdef SMP
@@ -143,17 +147,17 @@ sw1:
 	cmpl	$0,PCPU(CPUID)
 	je	1f
 
-	movl	PCPU(IDLEPROC), %eax
-	jmp	sw1b
+	movl	PCPU(IDLETHREAD), %eax
+	jmp	sw1b  /* Idle thread can run on any kernel context */
 1:
 #endif
 
 	/*
-	 * Choose a new process to schedule.  chooseproc() returns idleproc
+	 * Choose a new process to schedule.  choosethread() returns idleproc
 	 * if it cannot find another process to run.
 	 */
 sw1a:
-	call	chooseproc			/* trash ecx, edx, ret eax*/
+	call	choosethread			/* trash ecx, edx, ret eax*/
 
 #ifdef INVARIANTS
 	testl	%eax,%eax			/* no process? */
@@ -163,15 +167,20 @@ sw1b:
 	movl	%eax,%ecx
 
 #ifdef	INVARIANTS
-	cmpb	$SRUN,P_STAT(%ecx)
+	movl	TD_PROC(%ecx), %eax	/* XXXKSE */
+	cmpb	$SRUN,P_STAT(%eax)
 	jne	badsw2
 #endif
 
-	movl	P_ADDR(%ecx),%edx
+	movl	TD_PCB(%ecx),%edx
 
 #if defined(SWTCH_OPTIM_STATS)
 	incl	swtch_optim_stats
 #endif
+
+/*##########################################################################*/
+/*##########################################################################*/
+/*##########################################################################*/
 	/* switch address space */
 	movl	%cr3,%ebx
 	cmpl	PCB_CR3(%edx),%ebx
@@ -181,9 +190,8 @@ sw1b:
 	incl	tlb_flush_count
 #endif
 	movl	PCB_CR3(%edx),%ebx
-	movl	%ebx,%cr3
+	movl	%ebx,%cr3			/* LOAD NEW PAGE TABLES */
 4:
-
 	movl	PCPU(CPUID), %esi
 	cmpl	$0, PCB_EXT(%edx)		/* has pcb extension? */
 	je	1f
@@ -191,12 +199,9 @@ sw1b:
 	movl	PCB_EXT(%edx), %edi		/* new tss descriptor */
 	jmp	2f
 1:
-
 	/* update common_tss.tss_esp0 pointer */
-	movl	%edx, %ebx			/* pcb */
-	addl	$(UPAGES * PAGE_SIZE - 16), %ebx
-	movl	%ebx, PCPU(COMMON_TSS) + TSS_ESP0
-
+	/* esp points to base of usable stack */
+	movl	%edx, PCPU(COMMON_TSS) + TSS_ESP0 /* stack is below pcb */
 	btrl	%esi, private_tss
 	jae	3f
 	PCPU_ADDR(COMMON_TSSD, %edi)
@@ -210,7 +215,9 @@ sw1b:
 	movl	$GPROC0_SEL*8, %esi		/* GSEL(entry, SEL_KPL) */
 	ltr	%si
 3:
-	movl	P_VMSPACE(%ecx), %ebx
+	/* note in a vmspace that this cpu is using it */
+	movl	TD_PROC(%ecx),%eax	/* get proc from thread XXXKSE */
+	movl	P_VMSPACE(%eax), %ebx	/* get vmspace of proc */
 	movl	PCPU(CPUID), %eax
 	btsl	%eax, VM_PMAP+PM_ACTIVE(%ebx)
 
@@ -233,22 +240,23 @@ sw1b:
 #endif /** GRAB_LOPRIO */
 #endif /* SMP */
 	movl	%edx, PCPU(CURPCB)
-	movl	%ecx, PCPU(CURPROC)		/* into next process */
+	movl	%ecx, PCPU(CURTHREAD)		/* into next process */
 
 #ifdef SMP
 	/* XXX FIXME: we should be restoring the local APIC TPR */
 #endif /* SMP */
 
-	cmpl	$0, PCB_USERLDT(%edx)
-	jnz	1f
-	movl	_default_ldt,%eax
-	cmpl	PCPU(CURRENTLDT),%eax
-	je	2f
-	lldt	_default_ldt
-	movl	%eax,PCPU(CURRENTLDT)
+	cmpl	$0, PCB_USERLDT(%edx)	/* if there is one */
+	jnz	1f			/* then use it */
+	movl	_default_ldt,%eax	/* We will use the default */
+	cmpl	PCPU(CURRENTLDT),%eax	/* check to see if already loaded */
+	je	2f			/* if so skip reload */
+	lldt	_default_ldt		/* load the default... we trust it. */
+	movl	%eax,PCPU(CURRENTLDT)	/* store what we have */
 	jmp	2f
-1:	pushl	%edx
-	call	set_user_ldt
+
+1:	pushl	%edx			/* call a non-trusting routine */
+	call	set_user_ldt		/* to check and load the ldt */
 	popl	%edx
 2:
 
@@ -275,7 +283,7 @@ cpu_switch_load_gs:
 	andl    $0x0000fc00,%eax         /*   reserved bits               */
 	pushl   %ebx
 	movl    PCB_DR7(%edx),%ebx
-	andl	$~0x0000fc00,%ebx
+	andl	$~0x0000fc00,%ebx	/* re-enable the restored watchpoints */
 	orl     %ebx,%eax
 	popl	%ebx
 	movl    %eax,%dr7
@@ -322,25 +330,25 @@ ENTRY(savectx)
 
 #ifdef DEV_NPX
 	/*
-	 * If npxproc == NULL, then the npx h/w state is irrelevant and the
+	 * If npxthread == NULL, then the npx h/w state is irrelevant and the
 	 * state had better already be in the pcb.  This is true for forks
 	 * but not for dumps (the old book-keeping with FP flags in the pcb
 	 * always lost for dumps because the dump pcb has 0 flags).
 	 *
-	 * If npxproc != NULL, then we have to save the npx h/w state to
-	 * npxproc's pcb and copy it to the requested pcb, or save to the
+	 * If npxthread != NULL, then we have to save the npx h/w state to
+	 * npxthread's pcb and copy it to the requested pcb, or save to the
 	 * requested pcb and reload.  Copying is easier because we would
 	 * have to handle h/w bugs for reloading.  We used to lose the
 	 * parent's npx state for forks by forgetting to reload.
 	 */
 	pushfl
 	cli
-	movl	PCPU(NPXPROC),%eax
+	movl	PCPU(NPXTHREAD),%eax
 	testl	%eax,%eax
 	je	1f
 
 	pushl	%ecx
-	movl	P_ADDR(%eax),%eax
+	movl	TD_PCB(%eax),%eax
 	leal	PCB_SAVEFPU(%eax),%eax
 	pushl	%eax
 	pushl	%eax