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From:   Song Shuai <suagrfillet@gmail.com>
To:     paul.walmsley@sifive.com, palmer@dabbelt.com,
        aou@eecs.berkeley.edu, conor.dooley@microchip.com,
        ajones@ventanamicro.com, sunilvl@ventanamicro.com,
        heiko.stuebner@vrull.eu, apatel@ventanamicro.com,
        suagrfillet@gmail.com, evan@rivosinc.com, greentime.hu@sifive.com,
        leyfoon.tan@starfivetech.com
Cc:     linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH V2] riscv: Add BUG_ON() for no cpu nodes in devicetree
Date:   Fri, 30 Jun 2023 18:59:38 +0800
Message-Id: <20230630105938.1377262-1-suagrfillet@gmail.com>
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When only the ACPI tables are passed to kernel, the tiny devictree created
by EFI Stub doesn't provide cpu nodes.

While if append the "acpi=off" to kernel cmdline to disable ACPI for kernel
the BUG_ON() in of_parse_and_init_cpus() indicates there's no boot cpu
found in the devicetree, not there're no cpu nodes in the devicetree.

Add BUG_ON() in the first place of of_parse_and_init_cpus() to make it clear.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
---
Changes since V1:
https://lore.kernel.org/linux-riscv/20230629105839.1160895-1-suagrfillet@gmail.com/
- revise the commit-msg and move the BUG_ON into of_parse_and_init_cpus() as Conor suggests

---
 arch/riscv/kernel/smpboot.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 6ca2b5309aab..04d33afbdf55 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -147,6 +147,8 @@ static void __init of_parse_and_init_cpus(void)
 	int cpuid = 1;
 	int rc;
 
+	BUG_ON(!of_get_next_cpu_node(NULL));
+
 	cpu_set_ops(0);
 
 	for_each_of_cpu_node(dn) {
-- 
2.20.1