From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH 07/19] ARM64 / ACPI: Parse MADT to map logical cpu to MPIDR and get cpu_possible/present_map Date: Wed, 30 Jul 2014 19:20:27 +0100 Message-ID: <53D9376B.5080609@arm.com> References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-8-git-send-email-hanjun.guo@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Return-path: Received: from service87.mimecast.com ([91.220.42.44]:60003 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755402AbaG3STx convert rfc822-to-8bit (ORCPT ); Wed, 30 Jul 2014 14:19:53 -0400 In-Reply-To: <1406206825-15590-8-git-send-email-hanjun.guo@linaro.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "hanjun.guo@linaro.org" , Catalin Marinas , "Rafael J. Wysocki" , Mark Rutland Cc: Sudeep Holla , "graeme.gregory@linaro.org" , Arnd Bergmann , "grant.likely@linaro.org" , Will Deacon , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Robert Richter , Lv Zheng , Robert Moore , Lorenzo Pieralisi , Liviu Dudau , Randy Dunlap , Charles Garcia-Tobin , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" On 24/07/14 14:00, 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 > Signed-off-by: Tomasz Nowicki > --- > arch/arm64/include/asm/acpi.h | 2 + > arch/arm64/kernel/acpi.c | 127 +++++++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/smp.c | 10 +++- > 3 files changed, 138 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 67dac90..5ce85f8 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -50,6 +50,8 @@ static inline bool acpi_has_cpu_in_madt(void) > extern int (*acpi_suspend_lowlevel)(void); > #define acpi_wakeup_address 0 > > +#define MAX_GIC_CPU_INTERFACE 65535 > + Can this me made something like MAX_MADT_INTERRUPT_CONTROLLER_ENTRIES ? And assuming each entry to be at-least 4 or 8 bytes, it can be reduced. > #endif /* CONFIG_ACPI */ > > #endif /*_ASM_ACPI_H*/ > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > index 374926f..801e268 100644 > --- a/arch/arm64/kernel/acpi.c > +++ b/arch/arm64/kernel/acpi.c > @@ -22,6 +22,9 @@ > #include > #include > > +#include > +#include > + > /* > * We never plan to use RSDT on arm/arm64 as its deprecated in spec but this > * variable is still required by the ACPI core > @@ -42,6 +45,9 @@ int acpi_psci_present; > /* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */ > int acpi_psci_use_hvc; > > +/* Processors (GICC) with enabled flag in MADT */ > +static int enabled_cpus; > + > /* > * __acpi_map_table() will be called before page_init(), so early_ioremap() > * or early_memremap() should be called here to for ACPI table mapping. > @@ -62,6 +68,122 @@ void __init __acpi_unmap_table(char *map, unsigned long size) > early_iounmap(map, size); > } > > +/** > + * acpi_register_gic_cpu_interface - register a gic cpu interface and > + * generates a logic cpu number > + * @mpidr: CPU's hardware id to register, MPIDR represented in MADT > + * @enabled: this cpu is enabled or not > + * > + * Returns the logic cpu number which maps to the gic cpu interface > + */ > +static int acpi_register_gic_cpu_interface(u64 mpidr, u8 enabled) Honestly this function doesn't deal anything with 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 logic 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 allocte again. > + */ > + cpu = 0; > + } else { > + cpu = cpumask_next_zero(-1, cpu_present_mask); > + } > + > + /* map the logic cpu id to cpu MPIDR */ > + cpu_logical_map(cpu) = mpidr; > + > + set_cpu_possible(cpu, true); > + set_cpu_present(cpu, true); > + I need to think more about this function and will comment later but I think these cpumasks should be set only if SMP and probably belong to smp.c > + 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->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); > + > + return 0; > +} > + > static int __init acpi_parse_fadt(struct acpi_table_header *table) > { > struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; > @@ -122,6 +244,11 @@ int __init acpi_boot_init(void) > if (err) > pr_err("Can't find FADT\n"); > > + /* Get the boot CPU's MPIDR before MADT parsing */ > + cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; > + As Mark suggested better to move this prior to ACPI changes. > + err = acpi_parse_madt_gic_cpu_interface_entries(); > + OK, so now you ignore if there was any FADT error if MADT is successfully parsed ? > 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 > #include > #include > +#include > > #include > #include > @@ -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 what I said above, it belongs here and we need to see how we do that. I will give it a thought. Regards, Sudeep From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755696AbaG3STz (ORCPT ); Wed, 30 Jul 2014 14:19:55 -0400 Received: from service87.mimecast.com ([91.220.42.44]:60006 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755575AbaG3STx convert rfc822-to-8bit (ORCPT ); Wed, 30 Jul 2014 14:19:53 -0400 Message-ID: <53D9376B.5080609@arm.com> Date: Wed, 30 Jul 2014 19:20:27 +0100 From: Sudeep Holla User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: "hanjun.guo@linaro.org" , Catalin Marinas , "Rafael J. Wysocki" , Mark Rutland CC: Sudeep Holla , "graeme.gregory@linaro.org" , Arnd Bergmann , "grant.likely@linaro.org" , Will Deacon , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Robert Richter , Lv Zheng , Robert Moore , Lorenzo Pieralisi , Liviu Dudau , Randy Dunlap , Charles Garcia-Tobin , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Tomasz Nowicki Subject: Re: [PATCH 07/19] ARM64 / ACPI: Parse MADT to map logical cpu to MPIDR and get cpu_possible/present_map References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-8-git-send-email-hanjun.guo@linaro.org> In-Reply-To: <1406206825-15590-8-git-send-email-hanjun.guo@linaro.org> X-OriginalArrivalTime: 30 Jul 2014 18:19:49.0692 (UTC) FILETIME=[D99E27C0:01CFAC22] X-MC-Unique: 114073019195000401 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/07/14 14:00, 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 > Signed-off-by: Tomasz Nowicki > --- > arch/arm64/include/asm/acpi.h | 2 + > arch/arm64/kernel/acpi.c | 127 +++++++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/smp.c | 10 +++- > 3 files changed, 138 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 67dac90..5ce85f8 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -50,6 +50,8 @@ static inline bool acpi_has_cpu_in_madt(void) > extern int (*acpi_suspend_lowlevel)(void); > #define acpi_wakeup_address 0 > > +#define MAX_GIC_CPU_INTERFACE 65535 > + Can this me made something like MAX_MADT_INTERRUPT_CONTROLLER_ENTRIES ? And assuming each entry to be at-least 4 or 8 bytes, it can be reduced. > #endif /* CONFIG_ACPI */ > > #endif /*_ASM_ACPI_H*/ > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > index 374926f..801e268 100644 > --- a/arch/arm64/kernel/acpi.c > +++ b/arch/arm64/kernel/acpi.c > @@ -22,6 +22,9 @@ > #include > #include > > +#include > +#include > + > /* > * We never plan to use RSDT on arm/arm64 as its deprecated in spec but this > * variable is still required by the ACPI core > @@ -42,6 +45,9 @@ int acpi_psci_present; > /* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */ > int acpi_psci_use_hvc; > > +/* Processors (GICC) with enabled flag in MADT */ > +static int enabled_cpus; > + > /* > * __acpi_map_table() will be called before page_init(), so early_ioremap() > * or early_memremap() should be called here to for ACPI table mapping. > @@ -62,6 +68,122 @@ void __init __acpi_unmap_table(char *map, unsigned long size) > early_iounmap(map, size); > } > > +/** > + * acpi_register_gic_cpu_interface - register a gic cpu interface and > + * generates a logic cpu number > + * @mpidr: CPU's hardware id to register, MPIDR represented in MADT > + * @enabled: this cpu is enabled or not > + * > + * Returns the logic cpu number which maps to the gic cpu interface > + */ > +static int acpi_register_gic_cpu_interface(u64 mpidr, u8 enabled) Honestly this function doesn't deal anything with 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 logic 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 allocte again. > + */ > + cpu = 0; > + } else { > + cpu = cpumask_next_zero(-1, cpu_present_mask); > + } > + > + /* map the logic cpu id to cpu MPIDR */ > + cpu_logical_map(cpu) = mpidr; > + > + set_cpu_possible(cpu, true); > + set_cpu_present(cpu, true); > + I need to think more about this function and will comment later but I think these cpumasks should be set only if SMP and probably belong to smp.c > + 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->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); > + > + return 0; > +} > + > static int __init acpi_parse_fadt(struct acpi_table_header *table) > { > struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; > @@ -122,6 +244,11 @@ int __init acpi_boot_init(void) > if (err) > pr_err("Can't find FADT\n"); > > + /* Get the boot CPU's MPIDR before MADT parsing */ > + cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; > + As Mark suggested better to move this prior to ACPI changes. > + err = acpi_parse_madt_gic_cpu_interface_entries(); > + OK, so now you ignore if there was any FADT error if MADT is successfully parsed ? > 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 > #include > #include > +#include > > #include > #include > @@ -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 what I said above, it belongs here and we need to see how we do that. I will give it a thought. Regards, Sudeep From mboxrd@z Thu Jan 1 00:00:00 1970 From: sudeep.holla@arm.com (Sudeep Holla) Date: Wed, 30 Jul 2014 19:20:27 +0100 Subject: [PATCH 07/19] ARM64 / ACPI: Parse MADT to map logical cpu to MPIDR and get cpu_possible/present_map In-Reply-To: <1406206825-15590-8-git-send-email-hanjun.guo@linaro.org> References: <1406206825-15590-1-git-send-email-hanjun.guo@linaro.org> <1406206825-15590-8-git-send-email-hanjun.guo@linaro.org> Message-ID: <53D9376B.5080609@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 24/07/14 14:00, 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 > Signed-off-by: Tomasz Nowicki > --- > arch/arm64/include/asm/acpi.h | 2 + > arch/arm64/kernel/acpi.c | 127 +++++++++++++++++++++++++++++++++++++++++ > arch/arm64/kernel/smp.c | 10 +++- > 3 files changed, 138 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 67dac90..5ce85f8 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -50,6 +50,8 @@ static inline bool acpi_has_cpu_in_madt(void) > extern int (*acpi_suspend_lowlevel)(void); > #define acpi_wakeup_address 0 > > +#define MAX_GIC_CPU_INTERFACE 65535 > + Can this me made something like MAX_MADT_INTERRUPT_CONTROLLER_ENTRIES ? And assuming each entry to be at-least 4 or 8 bytes, it can be reduced. > #endif /* CONFIG_ACPI */ > > #endif /*_ASM_ACPI_H*/ > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > index 374926f..801e268 100644 > --- a/arch/arm64/kernel/acpi.c > +++ b/arch/arm64/kernel/acpi.c > @@ -22,6 +22,9 @@ > #include > #include > > +#include > +#include > + > /* > * We never plan to use RSDT on arm/arm64 as its deprecated in spec but this > * variable is still required by the ACPI core > @@ -42,6 +45,9 @@ int acpi_psci_present; > /* 1 to indicate HVC must be used instead of SMC as the PSCI conduit */ > int acpi_psci_use_hvc; > > +/* Processors (GICC) with enabled flag in MADT */ > +static int enabled_cpus; > + > /* > * __acpi_map_table() will be called before page_init(), so early_ioremap() > * or early_memremap() should be called here to for ACPI table mapping. > @@ -62,6 +68,122 @@ void __init __acpi_unmap_table(char *map, unsigned long size) > early_iounmap(map, size); > } > > +/** > + * acpi_register_gic_cpu_interface - register a gic cpu interface and > + * generates a logic cpu number > + * @mpidr: CPU's hardware id to register, MPIDR represented in MADT > + * @enabled: this cpu is enabled or not > + * > + * Returns the logic cpu number which maps to the gic cpu interface > + */ > +static int acpi_register_gic_cpu_interface(u64 mpidr, u8 enabled) Honestly this function doesn't deal anything with 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 logic 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 allocte again. > + */ > + cpu = 0; > + } else { > + cpu = cpumask_next_zero(-1, cpu_present_mask); > + } > + > + /* map the logic cpu id to cpu MPIDR */ > + cpu_logical_map(cpu) = mpidr; > + > + set_cpu_possible(cpu, true); > + set_cpu_present(cpu, true); > + I need to think more about this function and will comment later but I think these cpumasks should be set only if SMP and probably belong to smp.c > + 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->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); > + > + return 0; > +} > + > static int __init acpi_parse_fadt(struct acpi_table_header *table) > { > struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; > @@ -122,6 +244,11 @@ int __init acpi_boot_init(void) > if (err) > pr_err("Can't find FADT\n"); > > + /* Get the boot CPU's MPIDR before MADT parsing */ > + cpu_logical_map(0) = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; > + As Mark suggested better to move this prior to ACPI changes. > + err = acpi_parse_madt_gic_cpu_interface_entries(); > + OK, so now you ignore if there was any FADT error if MADT is successfully parsed ? > 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 > #include > #include > +#include > > #include > #include > @@ -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 what I said above, it belongs here and we need to see how we do that. I will give it a thought. Regards, Sudeep