[PATCH v2] mips: smp-bmips: fix CPU mappings

From: Álvaro Fernández Rojas
Date: Wed Feb 24 2021 - 02:34:38 EST


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@xxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
---
v2: Fix duplicated line

arch/mips/kernel/smp-bmips.c | 27 +++++++++++++++++----------
1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c
index 359b176b665f..b6ef5f7312cf 100644
--- 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;
-
- for (i = 0; i < max_cpus; i++) {
- if (i != boot_cpu) {
- __cpu_number_map[i] = cpu;
- __cpu_logical_map[cpu] = i;
- 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++;
+ }
+ 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);
}
}

--
2.20.1