Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965549AbbBCNyW (ORCPT ); Tue, 3 Feb 2015 08:54:22 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:40860 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751867AbbBCNyS (ORCPT ); Tue, 3 Feb 2015 08:54:18 -0500 Date: Tue, 3 Feb 2015 13:53:48 +0000 From: Mark Rutland To: "hanjun.guo@linaro.org" Cc: Catalin Marinas , "Rafael J. Wysocki" , Olof Johansson , Arnd Bergmann , "grant.likely@linaro.org" , Will Deacon , Lorenzo Pieralisi , "graeme.gregory@linaro.org" , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Randy Dunlap , Charles Garcia-Tobin , "phoenix.liyi@huawei.com" , Timur Tabi , Ashwin Chaugule , "suravee.suthikulpanit@amd.com" , Mark Langsdorf , "wangyijing@huawei.com" , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linaro-acpi@lists.linaro.org" , Tomasz Nowicki Subject: Re: [PATCH v8 13/21] ARM64 / ACPI: Parse MADT for SMP initialization Message-ID: <20150203135348.GA31837@leverpostej> References: <1422881149-8177-1-git-send-email-hanjun.guo@linaro.org> <1422881149-8177-14-git-send-email-hanjun.guo@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1422881149-8177-14-git-send-email-hanjun.guo@linaro.org> Thread-Topic: [PATCH v8 13/21] ARM64 / ACPI: Parse MADT for SMP initialization Accept-Language: en-GB, en-US Content-Language: en-US User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6083 Lines: 157 On Mon, Feb 02, 2015 at 12:45:41PM +0000, 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. > > ACPI 5.1 only has two explicit methods to boot up SMP, PSCI and > Parking protocol, but the Parking protocol is only specified for > ARMv7 now, so make PSCI as the only way for the SMP boot protocol > before some updates for the ACPI spec or the Parking protocol spec. > > Parking protocol patches for SMP boot will be sent to upstream when > the new version of Parking protocol is ready. > > CC: Lorenzo Pieralisi > CC: Catalin Marinas > CC: Will Deacon > CC: Mark Rutland > Tested-by: Suravee Suthikulpanit > Tested-by: Yijing Wang > Tested-by: Mark Langsdorf > Tested-by: Jon Masters > Tested-by: Timur Tabi > Signed-off-by: Hanjun Guo > Signed-off-by: Tomasz Nowicki > --- > arch/arm64/include/asm/acpi.h | 2 + > arch/arm64/include/asm/cpu_ops.h | 1 + > arch/arm64/include/asm/smp.h | 5 +- > arch/arm64/kernel/acpi.c | 150 ++++++++++++++++++++++++++++++++++++++- > arch/arm64/kernel/cpu_ops.c | 2 +- > arch/arm64/kernel/setup.c | 7 +- > arch/arm64/kernel/smp.c | 2 +- > 7 files changed, 161 insertions(+), 8 deletions(-) [...] > +/** > + * acpi_map_gic_cpu_interface - generates a logical cpu number > + * and map to MPIDR represented by GICC structure > + * @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 MPIDR > + */ > +static int __init acpi_map_gic_cpu_interface(u64 mpidr, u8 enabled) > +{ > + int cpu; > + > + if (mpidr == INVALID_HWID) { > + pr_info("Skip MADT cpu entry with invalid MPIDR\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; > + } > + > + /* No need to check duplicate MPIDRs for the first CPU */ > + if (enabled_cpus) { > + /* > + * 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_possible_cpu(cpu) { > + if (cpu_logical_map(cpu) == mpidr) { > + pr_err("Firmware bug, duplicate CPU MPIDR: 0x%llx in MADT\n", > + mpidr); > + return -EINVAL; > + } > + } > + > + /* allocate a logical cpu id for the new comer */ > + cpu = cpumask_next_zero(-1, cpu_possible_mask); > + } else { > + /* > + * First GICC entry must be BSP as ACPI spec said > + * in section 5.2.12.15 > + */ > + if (cpu_logical_map(0) != mpidr) { > + pr_err("First GICC entry with MPIDR 0x%llx is not BSP\n", > + mpidr); > + return -EINVAL; > + } > + > + /* > + * boot_cpu_init() already hold bit 0 in cpu_possible_mask > + * for BSP, no need to allocate again. > + */ > + cpu = 0; > + } If/when kexec comes, on systems where CPU0 can be hotplugged the next kernel might boot on an AP rather than the BSP. Is there a requirement Linux-side that CPU0 is the BSP, or is this just intended as a sanity check of the tables the FW provided? > + > + if (!acpi_psci_present()) > + return -EOPNOTSUPP; > + > + cpu_ops[cpu] = cpu_get_ops("psci"); > + /* CPU 0 was already initialized */ > + if (cpu) { > + if (!cpu_ops[cpu]) > + return -EINVAL; > + > + if (cpu_ops[cpu]->cpu_init(NULL, cpu)) > + return -EOPNOTSUPP; > + > + /* map the logical cpu id to cpu MPIDR */ > + cpu_logical_map(cpu) = mpidr; > + > + set_cpu_possible(cpu, true); > + } In the OF case we only set CPUs possible once we've scanned all the nodes, and only when the boot CPU was actually found in a table. We should keep the ACPI case consistent with that. Can we not handle all of this in a later call once we've scanned all of the GICC structures? [...] > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index 43ae914..1099ddc 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -449,13 +449,16 @@ void __init setup_arch(char **cmdline_p) > if (acpi_disabled) { > unflatten_device_tree(); > psci_dt_init(); > + cpu_read_bootcpu_ops(); > +#ifdef CONFIG_SMP > + of_smp_init_cpus(); > +#endif I was going to say that it would be a little nicer if we had empty stubs for functions in the !SMP case, rather than #ifdefs all over the place. Unfortunately it looks like the way asm/smp.h is handled is generally a mess, so this isn't so bad for now. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/