path: root/arch/x86/include/asm/apic.h
diff options
authorThomas Gleixner <tglx@linutronix.de>2020-01-23 12:54:53 +0100
committerIngo Molnar <mingo@kernel.org>2020-01-29 12:50:12 +0100
commit979923871f69a4dc926658f9f9a1a4c1bde57552 (patch)
treee9067d24ec18e59a887eada03aead116d17935a8 /arch/x86/include/asm/apic.h
parent6bd3357b6181bd38c1a757168a8842e09ec6f3fb (diff)
x86/timer: Don't skip PIT setup when APIC is disabled or in legacy mode
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
Diffstat (limited to 'arch/x86/include/asm/apic.h')
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 2ebc17d9c72c..be0b9cf941c4 100644
--- 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(void) { }
# 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) { }

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