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Subject[PATCH 12/14] [IA64] Populate and use cpu_enabled_map
Date
Modify MADT local SAPIC parsing such that:

- all present CPUs added to cpu_present_map
- all enabled CPUs added to cpu_enabled_map

This change allows us to check during __cpu_up() if we should
actually bring up the CPU. That is, if a CPU is present, but not
enabled by firmware, we should not bring it up.

Contrariwise, by creating a sysfs interface for a disabled CPU,
we provide a hook that allows a user to interact with the CPU.

The most visible user interface change with this patch is that more
sysfs entries will appear in /sys/devices/system/cpu/cpuN/ on
multi-threaded systems with threads turned off.

The actual directories will be empty. A later patch in this series
will provide an example of using this new hook to provide a user
interface for disabled CPUs.

Signed-off-by: Alex Chiang <achiang@hp.com>
Cc: Tony Luck <tony.luck@intel.com>
---
arch/ia64/kernel/acpi.c | 16 +++++++++-------
arch/ia64/kernel/smpboot.c | 7 +++++++
include/asm-ia64/smp.h | 1 +
3 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 43687cc..1b4b338 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -212,13 +212,14 @@ acpi_parse_lsapic(struct acpi_subtable_header * header, const unsigned long end)

/*Skip BAD_MADT_ENTRY check, as lsapic size could vary */

- if (lsapic->lapic_flags & ACPI_MADT_ENABLED) {
#ifdef CONFIG_SMP
- smp_boot_data.cpu_phys_id[available_cpus] =
- (lsapic->id << 8) | lsapic->eid;
+ smp_boot_data.cpu_phys_id[available_cpus] =
+ (lsapic->id << 8) | lsapic->eid;
+
+ smp_boot_data.cpu_enabled[available_cpus] =
+ lsapic->lapic_flags & ACPI_MADT_ENABLED;
#endif
- ++available_cpus;
- }
+ ++available_cpus;

total_cpus++;
return 0;
@@ -872,8 +873,7 @@ int acpi_map_lsapic(acpi_handle handle, int *pcpu)

lsapic = (struct acpi_madt_local_sapic *)obj->buffer.pointer;

- if ((lsapic->header.type != ACPI_MADT_TYPE_LOCAL_SAPIC) ||
- (!(lsapic->lapic_flags & ACPI_MADT_ENABLED))) {
+ if (lsapic->header.type != ACPI_MADT_TYPE_LOCAL_SAPIC) {
kfree(buffer.pointer);
return -EINVAL;
}
@@ -892,6 +892,8 @@ int acpi_map_lsapic(acpi_handle handle, int *pcpu)
acpi_map_cpu2node(handle, cpu, physid);

cpu_set(cpu, cpu_present_map);
+ if (lsapic->lapic_flags & ACPI_MADT_ENABLED)
+ cpu_set(cpu, cpu_enabled_map);
ia64_cpu_to_sapicid[cpu] = physid;

*pcpu = cpu;
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index d7ad42b..caa1a44 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -582,14 +582,18 @@ smp_build_cpu_map (void)

ia64_cpu_to_sapicid[0] = boot_cpu_id;
cpus_clear(cpu_present_map);
+ cpus_clear(cpu_enabled_map);
cpu_set(0, cpu_present_map);
cpu_set(0, cpu_possible_map);
+ cpu_set(0, cpu_enabled_map);
for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
sapicid = smp_boot_data.cpu_phys_id[i];
if (sapicid == boot_cpu_id)
continue;
cpu_set(cpu, cpu_present_map);
cpu_set(cpu, cpu_possible_map);
+ if (smp_boot_data.cpu_enabled[cpu])
+ cpu_set(cpu, cpu_enabled_map);
ia64_cpu_to_sapicid[cpu] = sapicid;
cpu++;
}
@@ -820,6 +824,9 @@ __cpu_up (unsigned int cpu)
if (cpu_isset(cpu, cpu_callin_map))
return -EINVAL;

+ if (!cpu_isset(cpu, cpu_enabled_map))
+ return -EINVAL;
+
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
/* Processor goes to start_secondary(), sets online flag */
ret = do_boot_cpu(sapicid, cpu);
diff --git a/include/asm-ia64/smp.h b/include/asm-ia64/smp.h
index ec5f355..e5f60e8 100644
--- a/include/asm-ia64/smp.h
+++ b/include/asm-ia64/smp.h
@@ -55,6 +55,7 @@ extern int smp_call_function_mask(cpumask_t mask, void (*func)(void *),
extern struct smp_boot_data {
int cpu_count;
int cpu_phys_id[NR_CPUS];
+ int cpu_enabled[NR_CPUS];
} smp_boot_data __initdata;

extern char no_int_routing __devinitdata;


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