openwrt/target/linux/bmips/patches-5.10/040-v5.13-mips-smp-bmips-fix-CPU-mappings.patch

From c0f41a0dac1f3db6c40aabc0f3ac8868709ba6a6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Wed, 24 Feb 2021 08:33:36 +0100
Subject: [PATCH] mips: smp-bmips: fix CPU mappings
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When booting bmips with SMP enabled on a BCM6358 running on CPU #1 instead of
CPU #0, the current CPU mapping code produces the following:
- smp_processor_id(): 0
- cpu_logical_map(0): 1
- cpu_number_map(0): 1

This is because SMP isn't supported on BCM6358 since it has a shared TLB, so
it is disabled and max_cpus is decreased from 2 to 1.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
---
 arch/mips/kernel/smp-bmips.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

--- a/arch/mips/kernel/smp-bmips.c
+++ b/arch/mips/kernel/smp-bmips.c
@@ -134,17 +134,24 @@ static void __init bmips_smp_setup(void)
 	if (!board_ebase_setup)
 		board_ebase_setup = &bmips_ebase_setup;
 
-	__cpu_number_map[boot_cpu] = 0;
-	__cpu_logical_map[0] = boot_cpu;
+	if (max_cpus > 1) {
+		__cpu_number_map[boot_cpu] = 0;
+		__cpu_logical_map[0] = boot_cpu;
 
-	for (i = 0; i < max_cpus; i++) {
-		if (i != boot_cpu) {
-			__cpu_number_map[i] = cpu;
-			__cpu_logical_map[cpu] = i;
-			cpu++;
+		for (i = 0; i < max_cpus; i++) {
+			if (i != boot_cpu) {
+				__cpu_number_map[i] = cpu;
+				__cpu_logical_map[cpu] = i;
+				cpu++;
+			}
+			set_cpu_possible(i, 1);
+			set_cpu_present(i, 1);
 		}
-		set_cpu_possible(i, 1);
-		set_cpu_present(i, 1);
+	} else {
+		__cpu_number_map[0] = boot_cpu;
+		__cpu_logical_map[0] = 0;
+		set_cpu_possible(0, 1);
+		set_cpu_present(0, 1);
 	}
 }