On 04/08/14 16:28, Hanjun Guo wrote:
MADT contains the information for MPIDR which is essential for
SMP initialization, parse the GIC cpu interface structures to
get the MPIDR value and map it to cpu_logical_map(), and add
enabled cpu with valid MPIDR into cpu_possible_map and
cpu_present_map.
Signed-off-by: Hanjun Guo <hanjun....@linaro.org>
Signed-off-by: Tomasz Nowicki <tomasz.nowi...@linaro.org>
---
arch/arm64/include/asm/acpi.h | 2 +
arch/arm64/kernel/acpi.c | 129 ++++++++++++++++++++++++++++++++++++++++-
arch/arm64/kernel/smp.c | 10 +++-
3 files changed, 138 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index 6e04868..e877967 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -64,6 +64,8 @@ static inline void arch_fix_phys_package_id(int num, u32
slot) { }
extern int (*acpi_suspend_lowlevel)(void);
#define acpi_wakeup_address 0
+#define MAX_GIC_CPU_INTERFACE 65535
+
Did you get this information from GIC specification ?
IIUC you are trying to represent max number of interrupt controller
entries MADT can possibly have. So, I had suggested to change the name
like MAX_MADT_INTERRUPT_CONTROLLER_ENTRIES so that it is not GIC specific.
#endif /* CONFIG_ACPI */
#endif /*_ASM_ACPI_H*/
diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 69a315d..9e07d99 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -22,6 +22,9 @@
#include <linux/bootmem.h>
#include <linux/smp.h>
+#include <asm/smp_plat.h>
+#include <asm/cputype.h>
+
int acpi_noirq; /* skip ACPI IRQ initialization */
int acpi_disabled;
EXPORT_SYMBOL(acpi_disabled);
@@ -29,6 +32,8 @@ EXPORT_SYMBOL(acpi_disabled);
int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ
initialization */
EXPORT_SYMBOL(acpi_pci_disabled);
+static int enabled_cpus; /* Processors (GICC) with enabled flag in MADT
*/
+
/*
* __acpi_map_table() will be called before page_init(), so early_ioremap()
* or early_memremap() should be called here to for ACPI table mapping.
@@ -49,6 +54,122 @@ void __init __acpi_unmap_table(char *map, unsigned long
size)
early_memunmap(map, size);
}
+/**
+ * acpi_register_gic_cpu_interface - register a gic cpu interface and
+ * generates a logical cpu number
+ * @mpidr: CPU's hardware id to register, MPIDR represented in MADT
+ * @enabled: this cpu is enabled or not
+ *
+ * Returns the logical cpu number which maps to the gic cpu interface
+ */
+static int acpi_register_gic_cpu_interface(u64 mpidr, u8 enabled)
+{
IMO the function name gives me a wrong idea that you are registering
something with GIC. How about acpi_map_gic_cpu_interface ?
+ int cpu;
+
+ if (mpidr == INVALID_HWID) {
+ pr_info("Skip invalid cpu hardware ID\n");
+ return -EINVAL;
+ }
+
+ total_cpus++;
+ if (!enabled)
+ return -EINVAL;
+
+ if (enabled_cpus >= NR_CPUS) {
+ pr_warn("NR_CPUS limit of %d reached, Processor %d/0x%llx
ignored.\n",
+ NR_CPUS, total_cpus, mpidr);
+ return -EINVAL;
+ }
+
+ /* If it is the first CPU, no need to check duplicate MPIDRs */
+ if (!enabled_cpus)
+ goto skip_mpidr_check;
+
+ /*
+ * Duplicate MPIDRs are a recipe for disaster. Scan
+ * all initialized entries and check for
+ * duplicates. If any is found just ignore the CPU.
+ */
+ for_each_present_cpu(cpu) {
+ if (cpu_logical_map(cpu) == mpidr) {
+ pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in
MADT\n",
+ mpidr);
+ return -EINVAL;
+ }
+ }
+
+skip_mpidr_check:
+ enabled_cpus++;
+
+ /* allocate a logical cpu id for the new comer */
+ if (cpu_logical_map(0) == mpidr) {
+ /*
+ * boot_cpu_init() already hold bit 0 in cpu_present_mask
+ * for BSP, no need to allocate again.
+ */
+ cpu = 0;
+ } else {
+ cpu = cpumask_next_zero(-1, cpu_present_mask);
+ }
+
+ /* map the logical cpu id to cpu MPIDR */
+ cpu_logical_map(cpu) = mpidr;
+
+ set_cpu_possible(cpu, true);
IMO it better to keep all these updates to cpumasks contained in the
smp.c as I had mentioned before. I think you can refactor smp_init_cpus
to achieve that.
+ set_cpu_present(cpu, true);
This is totally wrong ? What would you do if the cpu failed to
initialize ? I don't see that handled.
+
+ return cpu;
+}
+
+static int __init
+acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header,
+ const unsigned long end)
+{
+ struct acpi_madt_generic_interrupt *processor;
+
+ processor = (struct acpi_madt_generic_interrupt *)header;
+
+ if (BAD_MADT_ENTRY(processor, end))
+ return -EINVAL;
+
+ acpi_table_print_madt_entry(header);
+
+ acpi_register_gic_cpu_interface(processor->arm_mpidr,
+ processor->flags & ACPI_MADT_ENABLED);
+
+ return 0;
+}
+
+/*
+ * Parse GIC cpu interface related entries in MADT
+ * returns 0 on success, < 0 on error
+ */
+static int __init acpi_parse_madt_gic_cpu_interface_entries(void)
+{
+ int count;
+
+ /*
+ * do a partial walk of MADT to determine how many CPUs
+ * we have including disabled CPUs, and get information
+ * we need for SMP init
+ */
+ count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
+ acpi_parse_gic_cpu_interface, MAX_GIC_CPU_INTERFACE);
+
+ if (!count) {
+ pr_err("No GIC CPU interface entries present\n");
+ return -ENODEV;
+ } else if (count < 0) {
+ pr_err("Error parsing GIC CPU interface entry\n");
+ return count;
+ }
+
+ /* Make boot-up look pretty */
+ pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus);
Ideally just setup cpu_logical_map in acpi_parse_gic_cpu_interface and
setup cpumasks in smp_init_cpus.
+
+ return 0;
+}
+
static int __init acpi_parse_fadt(struct acpi_table_header *table)
{
struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table;
@@ -99,8 +220,12 @@ int __init acpi_boot_init(void)
return -ENODEV;
err = acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt);
- if (err)
- pr_err("Can't find FADT\n");
+ if (err) {
+ pr_err("Can't find FADT or error happened during parsing
FADT\n");
+ return err;
+ }
+
+ err = acpi_parse_madt_gic_cpu_interface_entries();
return err;
}
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 40f38f4..8f1d37c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -36,6 +36,7 @@
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/irq_work.h>
+#include <linux/acpi.h>
#include <asm/atomic.h>
#include <asm/cacheflush.h>
@@ -458,7 +459,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
if (err)
continue;
- set_cpu_present(cpu, true);
+ /*
+ * In ACPI mode, cpu_present_map was initialised when
+ * MADT table was parsed which before this function
+ * is called.
+ */
+ if (acpi_disabled)
+ set_cpu_present(cpu, true);
+
This is the right place to set the cpu present based on the return value
of cpu_prepare.
max_cpus--;
}
}
--
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