As a first step towards supporting multi-cluster systems, detect cores &
VPs in secondary clusters & record their cluster information in the
cpu_data array. The "VP topology" line printed during boot is extended
to display multiple clusters. On a single cluster it shows output like
the following:
VP topology: {4,4}
This would indicate a system with 2 cores which each contain 4 VPs. We
extend this to cover multiple clusters in a natural way:
VP topology: {4,4},{2,2}
This would indicate a system with 2 clusters. The first cluster contains
2 cores which each contain 4 VPs. The second cluster contains 2 cores
which each contain 2 VPs.
Actually booting these cores & VPs is left to further patches once other
pieces are in place.
Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/kernel/smp-cps.c | 80 +++++++++++++++++++++++++++++-----------------
1 file changed, 51 insertions(+), 29 deletions(-)
diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
index 4b9dcca12e5f..0d9cda6a77de 100644
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -40,44 +40,58 @@ static int __init setup_nothreads(char *s)
}
early_param("nothreads", setup_nothreads);
-static unsigned core_vpe_count(unsigned core)
+static unsigned core_vpe_count(unsigned int cluster, unsigned core)
{
if (threads_disabled)
return 1;
- return mips_cps_numvps(0, core);
+ return mips_cps_numvps(cluster, core);
}
static void __init cps_smp_setup(void)
{
- unsigned int ncores, nvpes, core_vpes;
+ unsigned int nclusters, ncores, nvpes, core_vpes;
unsigned long core_entry;
- int c, v;
+ int cl, c, v;
/* Detect & record VPE topology */
- ncores = mips_cps_numcores(0);
+ nvpes = 0;
+ nclusters = mips_cps_numclusters();
pr_info("%s topology ", cpu_has_mips_r6 ? "VP" : "VPE");
- for (c = nvpes = 0; c < ncores; c++) {
- core_vpes = core_vpe_count(c);
- pr_cont("%c%u", c ? ',' : '{', core_vpes);
-
- /* Use the number of VPEs in core 0 for smp_num_siblings */
- if (!c)
- smp_num_siblings = core_vpes;
+ for (cl = 0; cl < nclusters; cl++) {
+ if (cl > 0)
+ pr_cont(",");
+ pr_cont("{");
+
+ ncores = mips_cps_numcores(cl);
+ for (c = 0; c < ncores; c++) {
+ core_vpes = core_vpe_count(cl, c);
+
+ if (c > 0)
+ pr_cont(",");
+ pr_cont("%u", core_vpes);
+
+ /* Use the number of VPEs in cluster 0 core 0 for smp_num_siblings */
+ if (!cl && !c)
+ smp_num_siblings = core_vpes;
+
+ for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
+ cpu_set_cluster(&cpu_data[nvpes + v], cl);
+ cpu_set_core(&cpu_data[nvpes + v], c);
+ cpu_set_vpe_id(&cpu_data[nvpes + v], v);
+ }
- for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
- cpu_set_core(&cpu_data[nvpes + v], c);
- cpu_set_vpe_id(&cpu_data[nvpes + v], v);
+ nvpes += core_vpes;
}
- nvpes += core_vpes;
+ pr_cont("}");
}
- pr_cont("} total %u\n", nvpes);
+ pr_cont(" total %u\n", nvpes);
/* Indicate present CPUs (CPU being synonymous with VPE) */
for (v = 0; v < min_t(unsigned, nvpes, NR_CPUS); v++) {
- set_cpu_possible(v, true);
- set_cpu_present(v, true);
+ set_cpu_possible(v, cpu_cluster(&cpu_data[v]) == 0);
+ set_cpu_present(v, cpu_cluster(&cpu_data[v]) == 0);
__cpu_number_map[v] = v;
__cpu_logical_map[v] = v;
}
@@ -109,7 +123,7 @@ static void __init cps_smp_setup(void)
static void __init cps_prepare_cpus(unsigned int max_cpus)
{
unsigned ncores, core_vpes, c, cca;
- bool cca_unsuitable;
+ bool cca_unsuitable, cores_limited;
u32 *entry_code;
mips_mt_set_cpuoptions();
@@ -129,19 +143,22 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
}
/* Warn the user if the CCA prevents multi-core */
- ncores = mips_cps_numcores(0);
- if ((cca_unsuitable || cpu_has_dc_aliases) && ncores > 1) {
+ cores_limited = false;
+ if (cca_unsuitable || cpu_has_dc_aliases) {
+ for_each_present_cpu(c) {
+ if (cpus_are_siblings(smp_processor_id(), c))
+ continue;
+
+ set_cpu_present(c, false);
+ cores_limited = true;
+ }
+ }
+ if (cores_limited)
pr_warn("Using only one core due to %s%s%s\n",
cca_unsuitable ? "unsuitable CCA" : "",
(cca_unsuitable && cpu_has_dc_aliases) ? " & " : "",
cpu_has_dc_aliases ? "dcache aliasing" : "");
- for_each_present_cpu(c) {
- if (!cpus_are_siblings(smp_processor_id(), c))
- set_cpu_present(c, false);
- }
- }
-
/*
* Patch the start of mips_cps_core_entry to provide:
*
@@ -156,6 +173,7 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
__sync();
/* Allocate core boot configuration structs */
+ ncores = mips_cps_numcores(0);
mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
GFP_KERNEL);
if (!mips_cps_core_bootcfg) {
@@ -165,7 +183,7 @@ static void __init cps_prepare_cpus(unsigned int max_cpus)
/* Allocate VPE boot configuration structs */
for (c = 0; c < ncores; c++) {
- core_vpes = core_vpe_count(c);
+ core_vpes = core_vpe_count(0, c);
mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
sizeof(*mips_cps_core_bootcfg[c].vpe_config),
GFP_KERNEL);
@@ -288,6 +306,10 @@ static int cps_boot_secondary(int cpu, struct task_struct *idle)
unsigned int remote;
int err;
+ /* We don't yet support booting CPUs in other clusters */
+ if (cpu_cluster(&cpu_data[cpu]) != cpu_cluster(¤t_cpu_data))
+ return -ENOSYS;
+
vpe_cfg->pc = (unsigned long)&smp_bootstrap;
vpe_cfg->sp = __KSTK_TOS(idle);
vpe_cfg->gp = (unsigned long)task_thread_info(idle);
--
2.14.0
