On 09/10/23 5:00 pm, Pingfan Liu wrote:
If the boot_cpuid is smaller than nr_cpus, it requires extra effort to
ensure the boot_cpu is in cpu_present_mask. This can be achieved by
reserving the last quota for the boot cpu.
Note: the restriction on nr_cpus will be lifted with more effort in the
successive patches
Signed-off-by: Pingfan Liu <piliu@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Mahesh Salgaonkar <mahesh@xxxxxxxxxxxxx>
Cc: Wen Xiong <wenxiong@xxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: kexec@xxxxxxxxxxxxxxxxxxx
To: linuxppc-dev@xxxxxxxxxxxxxxxx
---
arch/powerpc/kernel/setup-common.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 81291e13dec0..f9ef0a2666b0 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -454,8 +454,8 @@ struct interrupt_server_node {
void __init smp_setup_cpu_maps(void)
{
struct device_node *dn;
- int shift = 0, cpu = 0;
- int j, nthreads = 1;
+ int terminate, shift = 0, cpu = 0;
+ int j, bt_thread = 0, nthreads = 1;
int len;
struct interrupt_server_node *intserv_node, *n;
struct list_head *bt_node, head;
@@ -518,6 +518,7 @@ void __init smp_setup_cpu_maps(void)
for (j = 0 ; j < nthreads; j++) {
if (be32_to_cpu(intserv[j]) == boot_cpu_hwid) {
bt_node = &intserv_node->node;
+ bt_thread = j;
found_boot_cpu = true;
/*
* Record the round-shift between dt
@@ -537,11 +538,21 @@ void __init smp_setup_cpu_maps(void)
/* Select the primary thread, the boot cpu's slibing, as the logic 0 */
list_add_tail(&head, bt_node);
pr_info("the round shift between dt seq and the cpu logic number: %d\n", shift);
+ terminate = nr_cpu_ids;
list_for_each_entry(intserv_node, &head, node) {
+ j = 0;
+ /* Choose a start point to cover the boot cpu */
+ if (nr_cpu_ids - 1 < bt_thread) {
+ /*
+ * The processor core puts assumption on the thread id,
+ * not to breach the assumption.
+ */
+ terminate = nr_cpu_ids - 1;
nthreads is anyway assumed to be same for all cores. So, enforcing
nr_cpu_ids to a minimum of nthreads (and multiple of nthreads) should
make the code much simpler without the need for above check and the
other complexities addressed in the subsequent patches...
Thanks
Hari
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