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    SubjectRe: [PATCH 2/4] ACPI: Don't use acpi_lapic in ACPI core code
    Date
    On Wednesday, July 02, 2014 04:47:24 PM Hanjun Guo wrote:
    > From: Graeme Gregory <graeme.gregory@linaro.org>
    >
    > Now ARM64 support is being added to ACPI so architecture specific
    > values can not be used in core ACPI code.
    >
    > Following on the patch "ACPI / processor: Check if LAPIC is present
    > during initialization" which uses acpi_lapic in acpi_processor.c,
    > on ARM64 platform, GIC is used instead of local APIC, so acpi_lapic
    > is not a suitable value for ARM64.
    >
    > What is actually important at this point is the SMPness of the system,
    > so introduce acpi_arch_is_smp() to be arch specific and generic.
    >
    > Signed-off-by: Graeme Gregory <graeme.gregory@linaro.org>
    > Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
    > ---
    > arch/ia64/include/asm/acpi.h | 5 +++++
    > arch/x86/include/asm/acpi.h | 5 +++++
    > drivers/acpi/acpi_processor.c | 2 +-
    > 3 files changed, 11 insertions(+), 1 deletion(-)
    >
    > diff --git a/arch/ia64/include/asm/acpi.h b/arch/ia64/include/asm/acpi.h
    > index 75dc59a..2fc0757 100644
    > --- a/arch/ia64/include/asm/acpi.h
    > +++ b/arch/ia64/include/asm/acpi.h
    > @@ -40,6 +40,11 @@ extern int acpi_lapic;
    > #define acpi_noirq 0 /* ACPI always enabled on IA64 */
    > #define acpi_pci_disabled 0 /* ACPI PCI always enabled on IA64 */
    > #define acpi_strict 1 /* no ACPI spec workarounds on IA64 */
    > +
    > +static inline bool acpi_arch_is_smp(void)

    Why this name? In particular, local APIC being present doesn't imply SMP.

    > +{
    > + return acpi_lapic;

    Also

    return !!acpi_lapic;

    would be cleaner IMO.

    > +}
    > #endif
    > #define acpi_processor_cstate_check(x) (x) /* no idle limits on IA64 :) */
    > static inline void disable_acpi(void) { }
    > diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
    > index e06225e..939d377 100644
    > --- a/arch/x86/include/asm/acpi.h
    > +++ b/arch/x86/include/asm/acpi.h
    > @@ -121,6 +121,11 @@ static inline void arch_acpi_set_pdc_bits(u32 *buf)
    > buf[2] &= ~(ACPI_PDC_C_C2C3_FFH);
    > }
    >
    > +static inline bool acpi_arch_is_smp(void)
    > +{
    > + return acpi_lapic;
    > +}
    > +
    > #else /* !CONFIG_ACPI */
    >
    > #define acpi_lapic 0
    > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
    > index 1c08574..8622a0e 100644
    > --- a/drivers/acpi/acpi_processor.c
    > +++ b/drivers/acpi/acpi_processor.c
    > @@ -268,7 +268,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
    > pr->apic_id = apic_id;
    >
    > cpu_index = acpi_map_cpuid(pr->apic_id, pr->acpi_id);
    > - if (!cpu0_initialized && !acpi_lapic) {
    > + if (!cpu0_initialized && !acpi_arch_is_smp()) {
    > cpu0_initialized = 1;
    > /* Handle UP system running SMP kernel, with no LAPIC in MADT */
    > if ((cpu_index == -1) && (num_online_cpus() == 1))
    >

    --
    I speak only for myself.
    Rafael J. Wysocki, Intel Open Source Technology Center.


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