curpcb

[Konstantin Belousov]

On Wed, Jul 18, 2012 at 11:10:03AM +0300, Konstantin Belousov wrote:
> On Wed, Jul 18, 2012 at 04:59:38PM +1000, Bruce Evans wrote:
> > On Wed, 18 Jul 2012, Konstantin Belousov wrote:
> > Putting the definiton in machine/pcpu.h should avoid changing the
> > prerequistes for machine/pcb.h.
> > 
> > >#ifndef _KERNEL
> > >/* stuff that *used* to be included by user.h, or is now needed */
> > >
> > >Please note the location in pcb.h an not in machine/pcpu.h, where it
> > >cannot work for technical reasons (struct pcpu is not defined yet).
> > 
> > Not applicable -- see above.
> No, this cannot work. machine/pcpu.h defines PCPU_MD_FIELDS which is used
> to provide md part of the struct pcpu.

Below is the tested patch which converts all users of PCPU_GET(curpcb)
for amd64.

diff --git a/sys/amd64/amd64/fpu.c b/sys/amd64/amd64/fpu.c
index f88aba7..fe4bcf1 100644
--- a/sys/amd64/amd64/fpu.c
+++ b/sys/amd64/amd64/fpu.c
@@ -327,7 +327,7 @@ fpuexit(struct thread *td)
 	critical_enter();
 	if (curthread == PCPU_GET(fpcurthread)) {
 		stop_emulating();
-		fpusave(PCPU_GET(curpcb)->pcb_save);
+		fpusave(curpcb->pcb_save);
 		start_emulating();
 		PCPU_SET(fpcurthread, 0);
 	}
@@ -547,7 +547,7 @@ fputrap_x87(void)
 	 * wherever they are.
 	 */
 	if (PCPU_GET(fpcurthread) != curthread) {
-		pcb_save = PCPU_GET(curpcb)->pcb_save;
+		pcb_save = curpcb->pcb_save;
 		control = pcb_save->sv_env.en_cw;
 		status = pcb_save->sv_env.en_sw;
 	} else {
@@ -567,7 +567,7 @@ fputrap_sse(void)
 
 	critical_enter();
 	if (PCPU_GET(fpcurthread) != curthread)
-		mxcsr = PCPU_GET(curpcb)->pcb_save->sv_env.en_mxcsr;
+		mxcsr = curpcb->pcb_save->sv_env.en_mxcsr;
 	else
 		stmxcsr(&mxcsr);
 	critical_exit();
@@ -609,7 +609,7 @@ fpudna(void)
 	 * Record new context early in case frstor causes a trap.
 	 */
 	PCPU_SET(fpcurthread, curthread);
-	pcb = PCPU_GET(curpcb);
+	pcb = curpcb;
 
 	fpu_clean_state();
 
@@ -970,7 +970,7 @@ fpu_kern_thread(u_int flags)
 {
 	struct pcb *pcb;
 
-	pcb = PCPU_GET(curpcb);
+	pcb = curpcb;
 	KASSERT((curthread->td_pflags & TDP_KTHREAD) != 0,
 	    ("Only kthread may use fpu_kern_thread"));
 	KASSERT(pcb->pcb_save == get_pcb_user_save_pcb(pcb),
@@ -987,5 +987,5 @@ is_fpu_kern_thread(u_int flags)
 
 	if ((curthread->td_pflags & TDP_KTHREAD) == 0)
 		return (0);
-	return ((PCPU_GET(curpcb)->pcb_flags & PCB_KERNFPU) != 0);
+	return ((curpcb->pcb_flags & PCB_KERNFPU) != 0);
 }
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 8044fe5..cd3ebc5 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -996,7 +996,7 @@ exec_setregs(struct thread *td, struct image_params *imgp, u_long stack)
 		pcb->pcb_dr3 = 0;
 		pcb->pcb_dr6 = 0;
 		pcb->pcb_dr7 = 0;
-		if (pcb == PCPU_GET(curpcb)) {
+		if (pcb == curpcb) {
 			/*
 			 * Clear the debug registers on the running
 			 * CPU, otherwise they will end up affecting
diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index 57d1cc2..d035a7e 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -520,9 +520,8 @@ trap(struct trapframe *frame)
 				frame->tf_rip = (long)fsbase_load_fault;
 				goto out;
 			}
-			if (PCPU_GET(curpcb)->pcb_onfault != NULL) {
-				frame->tf_rip =
-				    (long)PCPU_GET(curpcb)->pcb_onfault;
+			if (curpcb->pcb_onfault != NULL) {
+				frame->tf_rip = (long)curpcb->pcb_onfault;
 				goto out;
 			}
 			break;
@@ -708,7 +707,7 @@ trap_pfault(frame, usermode)
 		 * it normally, and panic immediately.
 		 */
 		if (!usermode && (td->td_intr_nesting_level != 0 ||
-		    PCPU_GET(curpcb)->pcb_onfault == NULL)) {
+		    curpcb->pcb_onfault == NULL)) {
 			trap_fatal(frame, eva);
 			return (-1);
 		}
@@ -764,8 +763,8 @@ trap_pfault(frame, usermode)
 nogo:
 	if (!usermode) {
 		if (td->td_intr_nesting_level == 0 &&
-		    PCPU_GET(curpcb)->pcb_onfault != NULL) {
-			frame->tf_rip = (long)PCPU_GET(curpcb)->pcb_onfault;
+		    curpcb->pcb_onfault != NULL) {
+			frame->tf_rip = (long)curpcb->pcb_onfault;
 			return (0);
 		}
 		trap_fatal(frame, eva);
diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h
index 22cbbe2..d814902 100644
--- a/sys/amd64/include/pcb.h
+++ b/sys/amd64/include/pcb.h
@@ -144,6 +144,17 @@ void	makectx(struct trapframe *, struct pcb *);
 int	savectx(struct pcb *) __returns_twice;
 void	resumectx(struct pcb *);
 
+static __inline __pure2 struct pcb *
+__curpcb(void)
+{
+	struct pcb *pcb;
+
+	__asm("movq %%gs:%1,%0" : "=r" (pcb)
+	    : "m" (((struct pcpu *)NULL)->pc_curpcb));
+	return (pcb);
+}
+#define	curpcb		(__curpcb())
+
 #endif
 
 #endif /* _AMD64_PCB_H_ */
diff --git a/sys/sys/user.h b/sys/sys/user.h
index accb7c3..ab1c7a7 100644
--- a/sys/sys/user.h
+++ b/sys/sys/user.h
@@ -35,6 +35,7 @@
 #ifndef _SYS_USER_H_
 #define _SYS_USER_H_
 
+#include <sys/pcpu.h>
 #include <machine/pcb.h>
 #ifndef _KERNEL
 /* stuff that *used* to be included by user.h, or is now needed */
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