On Tue, Dec 3, 2013 at 10:39 AM, Hanjun Guo hanjun.guo@linaro.org wrote:
When boot the kernel with MADT, the cpu possible and present maps should be prefilled for cpu topology and acpi based cpu hot-plug.
The logic cpu id maps to APIC id (GIC id) is also implemented, it is needed for acpi processor drivers.
Signed-off-by: Hanjun Guo hanjun.guo@linaro.org
arch/arm64/include/asm/acpi.h | 10 ++-- arch/arm64/kernel/setup.c | 2 + arch/arm64/kernel/smp.c | 2 + drivers/acpi/plat/arm-core.c | 118 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 129 insertions(+), 3 deletions(-)
[snip]
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index a0c2ca6..1428024 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -420,7 +420,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus) if (err) continue;
+#ifndef CONFIG_ACPI set_cpu_present(cpu, true); +#endif
Should this be moved to DT cpu topology related code?
max_cpus--; }
} diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c index 45ff625..8527ecc 100644 --- a/drivers/acpi/plat/arm-core.c +++ b/drivers/acpi/plat/arm-core.c
[snip]
@@ -221,6 +284,61 @@ static int __init acpi_parse_madt_gic_distributor_entries(void) return 0; }
+static int setup_possible_cpus __initdata = -1; +static int __init _setup_possible_cpus(char *str) +{
get_option(&str, &setup_possible_cpus);
return 0;
+} +early_param("possible_cpus", _setup_possible_cpus);
This does not seem ACPI or ARM specific.
+/*
- cpu_possible_mask should be static, it cannot change as cpu's
- are onlined, or offlined. The reason is per-cpu data-structures
- are allocated by some modules at init time, and dont expect to
- do this dynamically on cpu arrival/departure.
- cpu_present_mask on the other hand can change dynamically.
- In case when cpu_hotplug is not compiled, then we resort to current
- behaviour, which is cpu_possible == cpu_present.
- Ashok Raj
- Three ways to find out the number of additional hotplug CPUs:
- If the BIOS specified disabled CPUs in ACPI/mptables use that.
- The user can overwrite it with possible_cpus=NUM
- Otherwise don't reserve additional CPUs.
- We do this because additional CPUs waste a lot of memory.
- -AK
- */
+void __init prefill_possible_map(void) +{
int i;
int possible, disabled_cpus;
disabled_cpus = total_cpus - available_cpus;
if (setup_possible_cpus == -1) {
if (disabled_cpus > 0)
setup_possible_cpus = disabled_cpus;
else
setup_possible_cpus = 0;
}
possible = available_cpus + setup_possible_cpus;
pr_info("SMP: the system is limited to %d CPUs\n", nr_cpu_ids);
if (possible > nr_cpu_ids)
possible = nr_cpu_ids;
pr_info("SMP: Allowing %d CPUs, %d hotplug CPUs\n",
possible, max((possible - available_cpus), 0));
for (i = 0; i < possible; i++)
set_cpu_possible(i, true);
for (; i < NR_CPUS; i++)
set_cpu_possible(i, false);
+}
This does not seem ACPI or ARM specific either.
Rob