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Message-ID: <20150312154117.GD18414@red-moon>
Date: Thu, 12 Mar 2015 15:41:17 +0000
From: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To: Hanjun Guo <hanjun.guo@...aro.org>
Cc: Catalin Marinas <Catalin.Marinas@....com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Will Deacon <Will.Deacon@....com>,
Olof Johansson <olof@...om.net>,
"grant.likely@...aro.org" <grant.likely@...aro.org>,
Arnd Bergmann <arnd@...db.de>,
Mark Rutland <Mark.Rutland@....com>,
"graeme.gregory@...aro.org" <graeme.gregory@...aro.org>,
Sudeep Holla <Sudeep.Holla@....com>,
"jcm@...hat.com" <jcm@...hat.com>,
Marc Zyngier <Marc.Zyngier@....com>,
Mark Brown <broonie@...nel.org>,
Robert Richter <rric@...nel.org>,
Timur Tabi <timur@...eaurora.org>,
Ashwin Chaugule <ashwinc@...eaurora.org>,
"suravee.suthikulpanit@....com" <suravee.suthikulpanit@....com>,
"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linaro-acpi@...ts.linaro.org" <linaro-acpi@...ts.linaro.org>
Subject: Re: [PATCH v10 14/21] ACPI / processor: Make it possible to get CPU
hardware ID via GICC
On Wed, Mar 11, 2015 at 12:39:40PM +0000, Hanjun Guo wrote:
> Introduce a new function map_gicc_mpidr() to allow MPIDRs to be obtained
> from the GICC Structure introduced by ACPI 5.1, since MPIDR for ARM64 is
> 64-bit, so typedef u64 for phys_cpuid_t.
>
> The ARM architecture defines the MPIDR register as the CPU hardware
> identifier. This patch adds the code infrastructure to retrieve the MPIDR
> values from the ARM ACPI GICC structure in order to look-up the kernel CPU
> hardware ids required by the ACPI core code to identify CPUs.
Nit: To me the two paragraphs above should be swapped, current log
sounds odd; first you define what an MPIDR is, then define what the patch
does with it, no need to respin.
I still have some reservations related to ACPI core code mapping
of physical to logical CPUs, in particular I loathe the multiple parsing
of MADT to get the same values twice - create cpu_logical_map and map
processor objects to logical cpu ids - but given the current state of
affairs, this patch looks fine:
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
> CC: Rafael J. Wysocki <rjw@...ysocki.net>
> CC: Catalin Marinas <catalin.marinas@....com>
> CC: Will Deacon <will.deacon@....com>
> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
> Tested-by: Yijing Wang <wangyijing@...wei.com>
> Tested-by: Mark Langsdorf <mlangsdo@...hat.com>
> Tested-by: Jon Masters <jcm@...hat.com>
> Tested-by: Timur Tabi <timur@...eaurora.org>
> Tested-by: Robert Richter <rrichter@...ium.com>
> Acked-by: Robert Richter <rrichter@...ium.com>
> Reviewed-by: Grant Likely <grant.likely@...aro.org>
> Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>
> ---
> arch/arm64/include/asm/acpi.h | 12 ++++++++++++
> drivers/acpi/processor_core.c | 30 ++++++++++++++++++++++++++++++
> 2 files changed, 42 insertions(+)
>
> diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
> index 9719921..eea0bc3 100644
> --- a/arch/arm64/include/asm/acpi.h
> +++ b/arch/arm64/include/asm/acpi.h
> @@ -13,6 +13,8 @@
> #define _ASM_ACPI_H
>
> #include <linux/mm.h>
> +#include <asm/cputype.h>
> +#include <asm/smp_plat.h>
>
> /* Basic configuration for ACPI */
> #ifdef CONFIG_ACPI
> @@ -27,6 +29,9 @@ static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys,
> }
> #define acpi_os_ioremap acpi_os_ioremap
>
> +typedef u64 phys_cpuid_t;
> +#define PHYS_CPUID_INVALID INVALID_HWID
> +
> #define acpi_strict 1 /* No out-of-spec workarounds on ARM64 */
> extern int acpi_disabled;
> extern int acpi_noirq;
> @@ -59,6 +64,13 @@ static inline void enable_acpi(void)
> }
>
> /*
> + * The ACPI processor driver for ACPI core code needs this macro
> + * to find out this cpu was already mapped (mapping from CPU hardware
> + * ID to CPU logical ID) or not.
> + */
> +#define cpu_physical_id(cpu) cpu_logical_map(cpu)
> +
> +/*
> * It's used from ACPI core in kdump to boot UP system with SMP kernel,
> * with this check the ACPI core will not override the CPU index
> * obtained from GICC with 0 and not print some error message as well.
> diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
> index 51cc299..b1ec78b 100644
> --- a/drivers/acpi/processor_core.c
> +++ b/drivers/acpi/processor_core.c
> @@ -83,6 +83,31 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
> return 0;
> }
>
> +/*
> + * Retrieve the ARM CPU physical identifier (MPIDR)
> + */
> +static int map_gicc_mpidr(struct acpi_subtable_header *entry,
> + int device_declaration, u32 acpi_id, phys_cpuid_t *mpidr)
> +{
> + struct acpi_madt_generic_interrupt *gicc =
> + container_of(entry, struct acpi_madt_generic_interrupt, header);
> +
> + if (!(gicc->flags & ACPI_MADT_ENABLED))
> + return -ENODEV;
> +
> + /* device_declaration means Device object in DSDT, in the
> + * GIC interrupt model, logical processors are required to
> + * have a Processor Device object in the DSDT, so we should
> + * check device_declaration here
> + */
> + if (device_declaration && (gicc->uid == acpi_id)) {
> + *mpidr = gicc->arm_mpidr;
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
> {
> unsigned long madt_end, entry;
> @@ -111,6 +136,9 @@ static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
> } else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
> if (!map_lsapic_id(header, type, acpi_id, &phys_id))
> break;
> + } else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT) {
> + if (!map_gicc_mpidr(header, type, acpi_id, &phys_id))
> + break;
> }
> entry += header->length;
> }
> @@ -143,6 +171,8 @@ static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
> map_lsapic_id(header, type, acpi_id, &phys_id);
> else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC)
> map_x2apic_id(header, type, acpi_id, &phys_id);
> + else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT)
> + map_gicc_mpidr(header, type, acpi_id, &phys_id);
>
> exit:
> kfree(buffer.pointer);
> --
> 1.9.1
>
>
--
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