| From 979923871f69a4dc926658f9f9a1a4c1bde57552 Mon Sep 17 00:00:00 2001 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Thu, 23 Jan 2020 12:54:53 +0100 |
| Subject: x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit 979923871f69a4dc926658f9f9a1a4c1bde57552 upstream. |
| |
| Tony reported a boot regression caused by the recent workaround for systems |
| which have a disabled (clock gate off) PIT. |
| |
| On his machine the kernel fails to initialize the PIT because |
| apic_needs_pit() does not take into account whether the local APIC |
| interrupt delivery mode will actually allow to setup and use the local |
| APIC timer. This should be easy to reproduce with acpi=off on the |
| command line which also disables HPET. |
| |
| Due to the way the PIT/HPET and APIC setup ordering works (APIC setup can |
| require working PIT/HPET) the information is not available at the point |
| where apic_needs_pit() makes this decision. |
| |
| To address this, split out the interrupt mode selection from |
| apic_intr_mode_init(), invoke the selection before making the decision |
| whether PIT is required or not, and add the missing checks into |
| apic_needs_pit(). |
| |
| Fixes: c8c4076723da ("x86/timer: Skip PIT initialization on modern chipsets") |
| Reported-by: Anthony Buckley <tony.buckley000@gmail.com> |
| Tested-by: Anthony Buckley <tony.buckley000@gmail.com> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Cc: Daniel Drake <drake@endlessm.com> |
| Link: https://bugzilla.kernel.org/show_bug.cgi?id=206125 |
| Link: https://lore.kernel.org/r/87sgk6tmk2.fsf@nanos.tec.linutronix.de |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/include/asm/apic.h | 2 ++ |
| arch/x86/include/asm/x86_init.h | 2 ++ |
| arch/x86/kernel/apic/apic.c | 23 ++++++++++++++++++----- |
| arch/x86/kernel/time.c | 12 ++++++++++-- |
| arch/x86/kernel/x86_init.c | 1 + |
| arch/x86/xen/enlighten_pv.c | 1 + |
| 6 files changed, 34 insertions(+), 7 deletions(-) |
| |
| --- a/arch/x86/include/asm/apic.h |
| +++ b/arch/x86/include/asm/apic.h |
| @@ -140,6 +140,7 @@ extern void apic_soft_disable(void); |
| extern void lapic_shutdown(void); |
| extern void sync_Arb_IDs(void); |
| extern void init_bsp_APIC(void); |
| +extern void apic_intr_mode_select(void); |
| extern void apic_intr_mode_init(void); |
| extern void init_apic_mappings(void); |
| void register_lapic_address(unsigned long address); |
| @@ -188,6 +189,7 @@ static inline void disable_local_APIC(vo |
| # define setup_secondary_APIC_clock x86_init_noop |
| static inline void lapic_update_tsc_freq(void) { } |
| static inline void init_bsp_APIC(void) { } |
| +static inline void apic_intr_mode_select(void) { } |
| static inline void apic_intr_mode_init(void) { } |
| static inline void lapic_assign_system_vectors(void) { } |
| static inline void lapic_assign_legacy_vector(unsigned int i, bool r) { } |
| --- a/arch/x86/include/asm/x86_init.h |
| +++ b/arch/x86/include/asm/x86_init.h |
| @@ -51,12 +51,14 @@ struct x86_init_resources { |
| * are set up. |
| * @intr_init: interrupt init code |
| * @trap_init: platform specific trap setup |
| + * @intr_mode_select: interrupt delivery mode selection |
| * @intr_mode_init: interrupt delivery mode setup |
| */ |
| struct x86_init_irqs { |
| void (*pre_vector_init)(void); |
| void (*intr_init)(void); |
| void (*trap_init)(void); |
| + void (*intr_mode_select)(void); |
| void (*intr_mode_init)(void); |
| }; |
| |
| --- a/arch/x86/kernel/apic/apic.c |
| +++ b/arch/x86/kernel/apic/apic.c |
| @@ -830,8 +830,17 @@ bool __init apic_needs_pit(void) |
| if (!tsc_khz || !cpu_khz) |
| return true; |
| |
| - /* Is there an APIC at all? */ |
| - if (!boot_cpu_has(X86_FEATURE_APIC)) |
| + /* Is there an APIC at all or is it disabled? */ |
| + if (!boot_cpu_has(X86_FEATURE_APIC) || disable_apic) |
| + return true; |
| + |
| + /* |
| + * If interrupt delivery mode is legacy PIC or virtual wire without |
| + * configuration, the local APIC timer wont be set up. Make sure |
| + * that the PIT is initialized. |
| + */ |
| + if (apic_intr_mode == APIC_PIC || |
| + apic_intr_mode == APIC_VIRTUAL_WIRE_NO_CONFIG) |
| return true; |
| |
| /* Virt guests may lack ARAT, but still have DEADLINE */ |
| @@ -1322,7 +1331,7 @@ void __init sync_Arb_IDs(void) |
| |
| enum apic_intr_mode_id apic_intr_mode __ro_after_init; |
| |
| -static int __init apic_intr_mode_select(void) |
| +static int __init __apic_intr_mode_select(void) |
| { |
| /* Check kernel option */ |
| if (disable_apic) { |
| @@ -1384,6 +1393,12 @@ static int __init apic_intr_mode_select( |
| return APIC_SYMMETRIC_IO; |
| } |
| |
| +/* Select the interrupt delivery mode for the BSP */ |
| +void __init apic_intr_mode_select(void) |
| +{ |
| + apic_intr_mode = __apic_intr_mode_select(); |
| +} |
| + |
| /* |
| * An initial setup of the virtual wire mode. |
| */ |
| @@ -1440,8 +1455,6 @@ void __init apic_intr_mode_init(void) |
| { |
| bool upmode = IS_ENABLED(CONFIG_UP_LATE_INIT); |
| |
| - apic_intr_mode = apic_intr_mode_select(); |
| - |
| switch (apic_intr_mode) { |
| case APIC_PIC: |
| pr_info("APIC: Keep in PIC mode(8259)\n"); |
| --- a/arch/x86/kernel/time.c |
| +++ b/arch/x86/kernel/time.c |
| @@ -91,10 +91,18 @@ void __init hpet_time_init(void) |
| |
| static __init void x86_late_time_init(void) |
| { |
| + /* |
| + * Before PIT/HPET init, select the interrupt mode. This is required |
| + * to make the decision whether PIT should be initialized correct. |
| + */ |
| + x86_init.irqs.intr_mode_select(); |
| + |
| + /* Setup the legacy timers */ |
| x86_init.timers.timer_init(); |
| + |
| /* |
| - * After PIT/HPET timers init, select and setup |
| - * the final interrupt mode for delivering IRQs. |
| + * After PIT/HPET timers init, set up the final interrupt mode for |
| + * delivering IRQs. |
| */ |
| x86_init.irqs.intr_mode_init(); |
| tsc_init(); |
| --- a/arch/x86/kernel/x86_init.c |
| +++ b/arch/x86/kernel/x86_init.c |
| @@ -80,6 +80,7 @@ struct x86_init_ops x86_init __initdata |
| .pre_vector_init = init_ISA_irqs, |
| .intr_init = native_init_IRQ, |
| .trap_init = x86_init_noop, |
| + .intr_mode_select = apic_intr_mode_select, |
| .intr_mode_init = apic_intr_mode_init |
| }, |
| |
| --- a/arch/x86/xen/enlighten_pv.c |
| +++ b/arch/x86/xen/enlighten_pv.c |
| @@ -1205,6 +1205,7 @@ asmlinkage __visible void __init xen_sta |
| x86_platform.get_nmi_reason = xen_get_nmi_reason; |
| |
| x86_init.resources.memory_setup = xen_memory_setup; |
| + x86_init.irqs.intr_mode_select = x86_init_noop; |
| x86_init.irqs.intr_mode_init = x86_init_noop; |
| x86_init.oem.arch_setup = xen_arch_setup; |
| x86_init.oem.banner = xen_banner; |