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arm64: add function to get a cpu's MADT GICC table
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Currently the ACPI parking protocol code needs to parse each CPU's MADT
GICC table to extract the mailbox address and so on. Each time we parse
a GICC table, we call back to the parking protocol code to parse it.

This has been fine so far, but we're about to have more code that needs
to extract data from the GICC tables, and adding a callback for each
user is going to get unwieldy.

Instead, this patch ensures that we stash a copy of each CPU's GICC
table at boot time, such that anything needing to parse it can later
request it. This will allow for other parsers of GICC, and for
simplification to the ACPI parking protocol code. Note that we must
store a copy, rather than a pointer, since the core ACPI code
temporarily maps/unmaps tables while iterating over them.

Since we parse the MADT before we know how many CPUs we have (and hence
before we setup the percpu areas), we must use an NR_CPUS sized array.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Mark Rutland authored and Will Deacon committed Apr 11, 2017
1 parent 18bfcfe commit e0013ae
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Showing 2 changed files with 12 additions and 0 deletions.
2 changes: 2 additions & 0 deletions arch/arm64/include/asm/acpi.h
Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,8 @@ static inline bool acpi_has_cpu_in_madt(void)
return true;
}

struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu);

static inline void arch_fix_phys_package_id(int num, u32 slot) { }
void __init acpi_init_cpus(void);

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10 changes: 10 additions & 0 deletions arch/arm64/kernel/smp.c
Original file line number Diff line number Diff line change
Expand Up @@ -518,6 +518,13 @@ static bool bootcpu_valid __initdata;
static unsigned int cpu_count = 1;

#ifdef CONFIG_ACPI
static struct acpi_madt_generic_interrupt cpu_madt_gicc[NR_CPUS];

struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu)
{
return &cpu_madt_gicc[cpu];
}

/*
* acpi_map_gic_cpu_interface - parse processor MADT entry
*
Expand Down Expand Up @@ -552,6 +559,7 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
return;
}
bootcpu_valid = true;
cpu_madt_gicc[0] = *processor;
early_map_cpu_to_node(0, acpi_numa_get_nid(0, hwid));
return;
}
Expand All @@ -562,6 +570,8 @@ acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
/* map the logical cpu id to cpu MPIDR */
cpu_logical_map(cpu_count) = hwid;

cpu_madt_gicc[cpu_count] = *processor;

/*
* Set-up the ACPI parking protocol cpu entries
* while initializing the cpu_logical_map to
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