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Subject[tip:x86/apic] x86/apic: Provide and use helper for send_IPI_allbutself()
Commit-ID:  22ca7ee933a39f542ff6f81fc64f8036eff56519
Gitweb: https://git.kernel.org/tip/22ca7ee933a39f542ff6f81fc64f8036eff56519
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 22 Jul 2019 20:47:23 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 25 Jul 2019 16:12:00 +0200

x86/apic: Provide and use helper for send_IPI_allbutself()

To support IPI shorthands wrap invocations of apic->send_IPI_allbutself()
in a helper function, so the static key controlling the shorthand mode is
only in one place.

Fixup all callers.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190722105220.492691679@linutronix.de

---
arch/x86/include/asm/apic.h | 2 ++
arch/x86/kernel/apic/ipi.c | 12 ++++++++++++
arch/x86/kernel/kgdb.c | 2 +-
arch/x86/kernel/reboot.c | 7 +------
arch/x86/kernel/smp.c | 4 ++--
5 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 4a0d349ab44d..de86c6c15228 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -177,6 +177,8 @@ extern void lapic_online(void);
extern void lapic_offline(void);
extern bool apic_needs_pit(void);

+extern void apic_send_IPI_allbutself(unsigned int vector);
+
#else /* !CONFIG_X86_LOCAL_APIC */
static inline void lapic_shutdown(void) { }
#define local_apic_timer_c2_ok 1
diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index 5bd8a001a887..f53de3e0145e 100644
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -50,6 +50,18 @@ void apic_smt_update(void)
static_branch_enable(&apic_use_ipi_shorthand);
}
}
+
+void apic_send_IPI_allbutself(unsigned int vector)
+{
+ if (num_online_cpus() < 2)
+ return;
+
+ if (static_branch_likely(&apic_use_ipi_shorthand))
+ apic->send_IPI_allbutself(vector);
+ else
+ apic->send_IPI_mask_allbutself(cpu_online_mask, vector);
+}
+
#endif /* CONFIG_SMP */

static inline int __prepare_ICR2(unsigned int mask)
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index a53dfb09880f..c44fe7d8d9a4 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -416,7 +416,7 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs)
*/
void kgdb_roundup_cpus(void)
{
- apic->send_IPI_allbutself(NMI_VECTOR);
+ apic_send_IPI_allbutself(NMI_VECTOR);
}
#endif

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 09d6bded3c1e..0cc7c0b106bb 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -828,11 +828,6 @@ static int crash_nmi_callback(unsigned int val, struct pt_regs *regs)
return NMI_HANDLED;
}

-static void smp_send_nmi_allbutself(void)
-{
- apic->send_IPI_allbutself(NMI_VECTOR);
-}
-
/*
* Halt all other CPUs, calling the specified function on each of them
*
@@ -861,7 +856,7 @@ void nmi_shootdown_cpus(nmi_shootdown_cb callback)
*/
wmb();

- smp_send_nmi_allbutself();
+ apic_send_IPI_allbutself(NMI_VECTOR);

/* Kick CPUs looping in NMI context. */
WRITE_ONCE(crash_ipi_issued, 1);
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 231fa230ebc7..b8ad1876a081 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -215,7 +215,7 @@ static void native_stop_other_cpus(int wait)
/* sync above data before sending IRQ */
wmb();

- apic->send_IPI_allbutself(REBOOT_VECTOR);
+ apic_send_IPI_allbutself(REBOOT_VECTOR);

/*
* Don't wait longer than a second for IPI completion. The
@@ -241,7 +241,7 @@ static void native_stop_other_cpus(int wait)

pr_emerg("Shutting down cpus with NMI\n");

- apic->send_IPI_allbutself(NMI_VECTOR);
+ apic_send_IPI_allbutself(NMI_VECTOR);
}
/*
* Don't wait longer than 10 ms if the caller didn't
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