From: Vitaly Kuznetsov Date: Tue, 28 Apr 2020 09:38:24 +0000 (+0200) Subject: x86/idt: Keep spurious entries unset in system_vectors X-Git-Tag: v5.8-rc1~21^2~136 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=1f1fbc70c10e81f70e9fbe2102d439c883269811;p=linux-2.6-block.git x86/idt: Keep spurious entries unset in system_vectors With commit dc20b2d52653 ("x86/idt: Move interrupt gate initialization to IDT code") non assigned system vectors are also marked as used in 'used_vectors' (now 'system_vectors') bitmap. This makes checks in arch_show_interrupts() whether a particular system vector is allocated to always pass and e.g. 'Hyper-V reenlightenment interrupts' entry always shows up in /proc/interrupts. Another side effect of having all unassigned system vectors marked as used is that irq_matrix_debug_show() will wrongly count them among 'System' vectors. As it is now ensured that alloc_intr_gate() is not called after init, it is possible to leave unused entries in 'system_vectors' unset to fix these issues. Signed-off-by: Vitaly Kuznetsov Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200428093824.1451532-4-vkuznets@redhat.com --- diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c index 0e9205137de8..36fef90a38e7 100644 --- a/arch/x86/kernel/idt.c +++ b/arch/x86/kernel/idt.c @@ -321,7 +321,11 @@ void __init idt_setup_apic_and_irq_gates(void) #ifdef CONFIG_X86_LOCAL_APIC for_each_clear_bit_from(i, system_vectors, NR_VECTORS) { - set_bit(i, system_vectors); + /* + * Don't set the non assigned system vectors in the + * system_vectors bitmap. Otherwise they show up in + * /proc/interrupts. + */ entry = spurious_entries_start + 8 * (i - FIRST_SYSTEM_VECTOR); set_intr_gate(i, entry); }