From 4b1669e8d1e4e6cb65b3b114fced6ca9bc39ddea Mon Sep 17 00:00:00 2001 From: Dou Liyang Date: Wed, 13 Sep 2017 17:12:45 +0800 Subject: [PATCH] x86/apic: Prepare for unifying the interrupt delivery modes setup There are three places which initialize the interrupt delivery modes: 1) init_bsp_APIC() which is called early might setup the through-local-APIC virtual wire mode on non SMP systems. 2) In an SMP-capable system, native_smp_prepare_cpus() tries to switch to symmetric I/O model. 3) In UP system with UP_LATE_INIT=y, the local APIC and I/O APIC are set up in smp_init(). There is no technical reason to make these initializations at random places and run the kernel with the potentially wrong mode through the early boot stage, but it has a problematic side effect: The late switch to symmetric I/O mode causes dump-capture kernel to hang when the kernel command line option 'notsc' is active. Provide a new function to unify that three positions. Preparatory patch to initialize an interrupt mode directly. Signed-off-by: Dou Liyang Signed-off-by: Thomas Gleixner Cc: yinghai@kernel.org Cc: bhe@redhat.com Link: https://lkml.kernel.org/r/1505293975-26005-3-git-send-email-douly.fnst@cn.fujitsu.com --- arch/x86/include/asm/apic.h | 2 ++ arch/x86/kernel/apic/apic.c | 16 ++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index 5f01671c68f2..1a970f5a6e75 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -128,6 +128,7 @@ extern void disable_local_APIC(void); extern void lapic_shutdown(void); extern void sync_Arb_IDs(void); extern void init_bsp_APIC(void); +extern void apic_intr_mode_init(void); extern void setup_local_APIC(void); extern void init_apic_mappings(void); void register_lapic_address(unsigned long address); @@ -170,6 +171,7 @@ static inline void disable_local_APIC(void) { } # define setup_boot_APIC_clock x86_init_noop # define setup_secondary_APIC_clock x86_init_noop static inline void lapic_update_tsc_freq(void) { } +static inline void apic_intr_mode_init(void) { } #endif /* !CONFIG_X86_LOCAL_APIC */ #ifdef CONFIG_X86_X2APIC diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 39cb8c1ad98e..08585bcbb38f 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1319,6 +1319,22 @@ void __init init_bsp_APIC(void) apic_write(APIC_LVT1, value); } +/* Init the interrupt delivery mode for the BSP */ +void __init apic_intr_mode_init(void) +{ + switch (apic_intr_mode_select()) { + case APIC_PIC: + pr_info("APIC: Keep in PIC mode(8259)\n"); + return; + case APIC_VIRTUAL_WIRE: + pr_info("APIC: Switch to virtual wire mode setup\n"); + return; + case APIC_SYMMETRIC_IO: + pr_info("APIC: Switch to symmectic I/O mode setup\n"); + return; + } +} + static void lapic_setup_esr(void) { unsigned int oldvalue, value, maxlvt; -- GitLab