Commit-ID: 4b1669e8d1e4e6cb65b3b114fced6ca9bc39ddea
Gitweb: http://git.kernel.org/tip/4b1669e8d1e4e6cb65b3b114fced6ca9bc39ddea
Author: Dou Liyang <douly.fnst@xxxxxxxxxxxxxx>
AuthorDate: Wed, 13 Sep 2017 17:12:45 +0800
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Mon, 25 Sep 2017 15:03:14 +0200
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 <douly.fnst@xxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: yinghai@xxxxxxxxxx
Cc: bhe@xxxxxxxxxx
Link: https://lkml.kernel.org/r/1505293975-26005-3-git-send-email-douly.fnst@xxxxxxxxxxxxxx
---
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 5f01671..1a970f5 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 39cb8c1..08585bc 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;
--
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