>Number:         19923
>Category:       kern
>Synopsis:       Post-nathanw_sa i386 kernel compilation error with PERFCTRS defined
>Confidential:   no
>Severity:       non-critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 18 20:37:00 PST 2003
>Closed-Date:
>Last-Modified:
>Originator:     David Sainty
>Release:        NetBSD 1.6M
>Organization:
Dynamic Technology Services and Products Ltd (NZ)
>Environment:
System: NetBSD tequila.dave.dtsp.co.nz 1.6K NetBSD 1.6K (TEQUILA-$Revision: 1.41 $) #1: Tue Dec 31 19:46:39 NZDT 2002 dave@tequila.dave.dtsp.co.nz:/vol/tequila/userD/NetBSD-current/src/sys/arch/i386/compile/TEQUILA i386
Architecture: i386
Machine: i386
>Description:
	"options PERFCTRS" causes code to be compiled that defines variables
	that are never used on some ports.  This causes the compile to fail.

>How-To-Repeat:
	Compile an i386 kernel (I'm sure i386 isn't the only affected port)
	with "options PERFCTRS" enabled.

cc  -ffreestanding -g -O2 -Werror -Wall -Wno-main -Wno-format-zero-length -Wpointer-arith -Wmissing-prototypes -Wstrict-prototypes -Wno-sign-compare -Wno-uninitialized  -Di386 -I.  -I../../../../arch -I../../../.. -nostdinc -DIPFORWSRCRT="0" -DFIFO -DMSGBUFSIZE="0x100000" -DDIAGNOSTIC -DUSB_DEBUG -DBTHCI_DEBUG -DTLP_MATCH_21140 -DMAXUSERS=16 -D_KERNEL -D_KERNEL_OPT   -c /usr/src/NetBSD-current/src/sys/arch/i386/compile/MERLOT/../../../../kern/sys_pmc.c
cc1: warnings being treated as errors
/usr/src/NetBSD-current/src/sys/arch/i386/compile/MERLOT/../../../../kern/sys_pmc.c: In function `sys_pmc_control':
/usr/src/NetBSD-current/src/sys/arch/i386/compile/MERLOT/../../../../kern/sys_pmc.c:70: warning: unused variable `p'
/usr/src/NetBSD-current/src/sys/arch/i386/compile/MERLOT/../../../../kern/sys_pmc.c: In function `sys_pmc_get_info':
/usr/src/NetBSD-current/src/sys/arch/i386/compile/MERLOT/../../../../kern/sys_pmc.c:140: warning: unused variable `p'
*** Error code 1

Stop.

>Fix:
	Here's one approach, the code looks a little repetitive, but it's
	probably a reasonable solution.

--- src/sys/kern/sys_pmc.c.orig	Sun Jan 19 16:22:29 2003
+++ src/sys/kern/sys_pmc.c	Sun Jan 19 17:19:22 2003
@@ -56,6 +56,15 @@
  * XXX We need a multiprocessor locking protocol!
  */
 
+/*
+ * The pmc_counter_*() interfaces are typically implemented as macros,
+ * and may not use the process reference.  By repeatedly using
+ * l->l_proc as the parameter (instead of factoring it out into a
+ * separate variable), we avoid compiler warnings on systems that
+ * define macros which never use that parameter.
+ */
+
+/*ARGSUSED*/
 int
 sys_pmc_control(struct lwp *l, void *v, register_t *rv)
 {
@@ -67,7 +76,6 @@
 		syscallarg(int) op;
 		syscallarg(void *) args;
 	} */ *uap = v;
-	struct proc *p = l->l_proc;
 	struct pmc_counter_cfg cfg;
 	void *args;
 	int ctr, operation, error=0;
@@ -77,33 +85,33 @@
 
 	switch (operation) {
 	case PMC_OP_START:
-		if (!pmc_counter_isconfigured(p, ctr)) {
+		if (!pmc_counter_isconfigured(l->l_proc, ctr)) {
 			return ENXIO;
 		}
-		if (pmc_counter_isrunning(p, ctr)) {
+		if (pmc_counter_isrunning(l->l_proc, ctr)) {
 			return EINPROGRESS;
 		}
-		pmc_enable_counter(p, ctr);
+		pmc_enable_counter(l->l_proc, ctr);
 		break;
 	case PMC_OP_STOP:
-		if (!pmc_counter_isconfigured(p, ctr)) {
+		if (!pmc_counter_isconfigured(l->l_proc, ctr)) {
 			return ENXIO;
 		}
-		if (!pmc_counter_isrunning(p, ctr)) {
+		if (!pmc_counter_isrunning(l->l_proc, ctr)) {
 			/* Nothing to do */
 			return 0;
 		}
-		pmc_disable_counter(p, ctr);
+		pmc_disable_counter(l->l_proc, ctr);
 		break;
 	case PMC_OP_CONFIGURE:
 		args = SCARG(uap, args);
 
-		if (pmc_counter_isrunning(p, ctr)) {
-			pmc_disable_counter(p, ctr);
+		if (pmc_counter_isrunning(l->l_proc, ctr)) {
+			pmc_disable_counter(l->l_proc, ctr);
 		}
 		error = copyin(args, &cfg, sizeof(struct pmc_counter_cfg));
 		if (error == 0) {
-			error = pmc_configure_counter(p, ctr, &cfg);
+			error = pmc_configure_counter(l->l_proc, ctr, &cfg);
 		}
 		break;
 	case PMC_OP_PROFSTART:
@@ -125,6 +133,7 @@
 #endif
 }
 
+/*ARGSUSED*/
 int
 sys_pmc_get_info(struct lwp *l, void *v, register_t *rv)
 {
@@ -137,7 +146,6 @@
 		syscallarg(void *) args;
 	} */ *uap = v;
 	uint64_t val;
-	struct proc *p = l->l_proc;
 	void *args;
 	int nctrs, ctr, ctrt, request, error=0, flags=0;
 
@@ -164,7 +172,7 @@
 		if (ctr < 0 || ctr >= nctrs) {
 			return EINVAL;
 		}
-		error = pmc_get_counter_value(p, ctr, flags, &val);
+		error = pmc_get_counter_value(l->l_proc, ctr, flags, &val);
 		if (error == 0) {
 			error = copyout(&val, args, sizeof(uint64_t));
 		}

>Release-Note:
>Audit-Trail:
>Unformatted: