From ca6db6b4970a11decfa67c9095ae61db080f3cd9 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 31 Mar 2021 02:02:16 +0000 Subject: [PATCH] x86/apic/of: Fix CPU devicetree-node lookups MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit stable inclusion from stable-5.10.26 commit 21536d7b7e6f58a2a7b3af3909c5150fe1fceb8c bugzilla: 51363 -------------------------------- commit dd926880da8dbbe409e709c1d3c1620729a94732 upstream. Architectures that describe the CPU topology in devicetree and do not have an identity mapping between physical and logical CPU ids must override the default implementation of arch_match_cpu_phys_id(). Failing to do so breaks CPU devicetree-node lookups using of_get_cpu_node() and of_cpu_device_node_get() which several drivers rely on. It also causes the CPU struct devices exported through sysfs to point to the wrong devicetree nodes. On x86, CPUs are described in devicetree using their APIC ids and those do not generally coincide with the logical ids, even if CPU0 typically uses APIC id 0. Add the missing implementation of arch_match_cpu_phys_id() so that CPU-node lookups work also with SMP. Apart from fixing the broken sysfs devicetree-node links this likely does not affect current users of mainline kernels on x86. Fixes: 4e07db9c8db8 ("x86/devicetree: Use CPU description from Device Tree") Signed-off-by: Johan Hovold Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210312092033.26317-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Chen Jun Acked-by:  Weilong Chen Signed-off-by: Zheng Zengkai --- arch/x86/kernel/apic/apic.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index f4c0514fc510..539f3e88ca7c 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2317,6 +2317,11 @@ static int cpuid_to_apicid[] = { [0 ... NR_CPUS - 1] = -1, }; +bool arch_match_cpu_phys_id(int cpu, u64 phys_id) +{ + return phys_id == cpuid_to_apicid[cpu]; +} + #ifdef CONFIG_SMP /** * apic_id_is_primary_thread - Check whether APIC ID belongs to a primary thread -- GitLab