Allow the platform code to return a bitmask of running cores rather than just

a number of cores, this allows for a sparse set of CPUs.  Implement support
for sparse core masks on Octeon.

XXX jeff@ suggests that all_cpus should include cores that are offline or
    running other applications/OSes, so the platform API should be further
    extended to allow us to set all_cpus to include all cores that are
    physically-present as opposed to only those that are running FreeBSD.

Submitted by:	Bhanu Prakash (with modifications)
Reviewed by:	jchandra
Glanced at by:	kib, jeff, jhb

5 files changed, 30 insertions, 22 deletions

diff --git a/sys/mips/cavium/octeon_mp.c b/sys/mips/cavium/octeon_mp.c
index 09d65de..78eafa6 100644
--- a/sys/mips/cavium/octeon_mp.c
+++ b/sys/mips/cavium/octeon_mp.c
@@ -102,10 +102,10 @@ platform_init_ap(int cpuid)
 	mips_wbflush();
 }
 
-int
-platform_num_processors(void)
+cpumask_t
+platform_cpu_mask(void)
 {
-	return (bitcount32(octeon_bootinfo->core_mask));
+       return (octeon_bootinfo->core_mask);
 }
 
 struct cpu_group *
diff --git a/sys/mips/include/hwfunc.h b/sys/mips/include/hwfunc.h
index fd89953..683aedb 100644
--- a/sys/mips/include/hwfunc.h
+++ b/sys/mips/include/hwfunc.h
@@ -89,9 +89,9 @@ void platform_ipi_clear(void);
 extern int platform_processor_id(void);
 
 /*
- * Return the number of processors available on this platform.
+ * Return the cpumask of available processors.
  */
-extern int platform_num_processors(void);
+extern cpumask_t platform_cpu_mask(void);
 
 /*
  * Return the topology of processors on this platform
diff --git a/sys/mips/mips/mp_machdep.c b/sys/mips/mips/mp_machdep.c
index 1203573..e945736 100644
--- a/sys/mips/mips/mp_machdep.c
+++ b/sys/mips/mips/mp_machdep.c
@@ -200,12 +200,14 @@ start_ap(int cpuid)
 void
 cpu_mp_setmaxid(void)
 {
+	cpumask_t cpumask;
 
-	mp_ncpus = platform_num_processors();
+	cpumask = platform_cpu_mask();
+	mp_ncpus = bitcount32(cpumask);
 	if (mp_ncpus <= 0)
 		mp_ncpus = 1;
 
-	mp_maxid = min(mp_ncpus, MAXCPU) - 1;
+	mp_maxid = min(fls(cpumask), MAXCPU) - 1;
 }
 
 void
@@ -231,24 +233,30 @@ void
 cpu_mp_start(void)
 {
 	int error, cpuid;
+	cpumask_t cpumask;
 
 	mtx_init(&ap_boot_mtx, "ap boot", NULL, MTX_SPIN);
 
-	all_cpus = 1;		/* BSP */
-	for (cpuid = 1; cpuid < platform_num_processors(); ++cpuid) {
+	all_cpus = 0;
+	cpumask = platform_cpu_mask();
+
+	while (cpumask != 0) {
+		cpuid = ffs(cpumask) - 1;
+		cpumask &= ~(1 << cpuid);
+
 		if (cpuid >= MAXCPU) {
 			printf("cpu_mp_start: ignoring AP #%d.\n", cpuid);
 			continue;
 		}
 
-		if ((error = start_ap(cpuid)) != 0) {
-			printf("AP #%d failed to start: %d\n", cpuid, error);
-			continue;
+		if (cpuid != platform_processor_id()) {
+			if ((error = start_ap(cpuid)) != 0) {
+				printf("AP #%d failed to start: %d\n", cpuid, error);
+				continue;
+			}
+			if (bootverbose)
+				printf("AP #%d started!\n", cpuid);
 		}
-		
-		if (bootverbose)
-			printf("AP #%d started!\n", cpuid);
-
 		all_cpus |= 1 << cpuid;
 	}
 
diff --git a/sys/mips/rmi/xlr_machdep.c b/sys/mips/rmi/xlr_machdep.c
index 71dae0f..4a1734a 100644
--- a/sys/mips/rmi/xlr_machdep.c
+++ b/sys/mips/rmi/xlr_machdep.c
@@ -614,11 +614,11 @@ platform_processor_id(void)
 	return (xlr_hwtid_to_cpuid[xlr_cpu_id()]);
 }
 
-int
-platform_num_processors(void)
+cpumask_t
+platform_cpu_mask(void)
 {
 
-	return (xlr_ncores * xlr_threads_per_core);
+	return (~0U >> (32 - (xlr_ncores * xlr_threads_per_core)));
 }
 
 struct cpu_group *
diff --git a/sys/mips/sibyte/sb_scd.c b/sys/mips/sibyte/sb_scd.c
index f0c7295..e5ac23c 100644
--- a/sys/mips/sibyte/sb_scd.c
+++ b/sys/mips/sibyte/sb_scd.c
@@ -242,11 +242,11 @@ sb_clear_mailbox(int cpu, uint64_t val)
 	sb_store64(regaddr, val);
 }
 
-int
-platform_num_processors(void)
+cpumask_t
+platform_cpu_mask(void)
 {
 
-	return (SYSREV_NUM_PROCESSORS(sb_read_sysrev()));
+	return (~0U >> (32 - SYSREV_NUM_PROCESSORS(sb_read_sysrev())));
 }
 #endif	/* SMP */