linux-kernel - [PATCH] parisc: simplify smp_prepare_boot

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Date:   Fri, 20 Oct 2023 15:45:30 +0100
From:   "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>
To:     Helge Deller <deller@....de>,
        "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>
Cc:     linux-kernel@...r.kernel.org, James Morse <james.morse@....com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Salil Mehta <salil.mehta@...wei.com>,
        linux-parisc@...r.kernel.org
Subject: [PATCH] parisc: simplify smp_prepare_boot_cpu()

smp_prepare_boot_cpu() reads the cpuid of the first CPU, printing a
message to state which processor booted, and setting it online and
present.

This cpuid is retrieved from per_cpu(cpu_data, 0).cpuid, which is
initialised in arch/parisc/kernel/processor.c:processor_probe() thusly:

	p = &per_cpu(cpu_data, cpuid);
...
	p->cpuid = cpuid;	/* save CPU id */

Consequently, the cpuid retrieved seems to be guaranteed to also be
zero, meaning that the message printed in this boils down to:

	pr_info("SMP: bootstrap CPU ID is 0\n");

Moreover, since kernel/cpu.c::boot_cpu_init() already sets CPU 0 to
be present and online, there is no need to do this again in
smp_prepare_boot_cpu().

Remove this code, and simplify the printk().

Signed-off-by: Russell King (Oracle) <rmk+kernel@...linux.org.uk>
---
 arch/parisc/kernel/smp.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 2019c1f04bd0..989efc8c67a5 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -404,13 +404,8 @@ static int smp_boot_one_cpu(int cpuid, struct task_struct *idle)

 void __init smp_prepare_boot_cpu(void)
 {
-	int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
-
 	/* Setup BSP mappings */
-	printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
-
-	set_cpu_online(bootstrap_processor, true);
-	set_cpu_present(bootstrap_processor, true);
+	pr_info("SMP: bootstrap CPU ID is 0\n");
 }

-- 
2.30.2