[PATCH 2/4] RISC-V: Implement nosmp commandline option.

[Atish Patra <atish.patra@wdc.com>]

nosmp command line option sets max_cpus to zero. No secondary harts
will boot if this is enabled. But present cpu mask will still point to
all possible masks.

Fix present cpu mask for nosmp usecase.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 arch/riscv/kernel/smpboot.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index eb533b5c2c8c..a8ad200581aa 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -47,6 +47,17 @@ void __init smp_prepare_boot_cpu(void)
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
+	int cpuid;
+
+	/* This covers non-smp usecase mandated by "nosmp" option */
+	if (max_cpus == 0)
+		return;
+
+	for_each_possible_cpu(cpuid) {
+		if (cpuid == smp_processor_id())
+			continue;
+		set_cpu_present(cpuid, true);
+	}
 }
 
 void __init setup_smp(void)
@@ -74,7 +85,6 @@ void __init setup_smp(void)
 
 		cpuid_to_hartid_map(cpuid) = hart;
 		set_cpu_possible(cpuid, true);
-		set_cpu_present(cpuid, true);
 		cpuid++;
 	}
 
-- 
2.21.0