[tip:x86/apic] x86/idt: Simplify alloc_intr_gate()

tip-bot for Thomas Gleixner
2017-08-29T11:27:16Z

Commit-ID: 4447ac1195a845b18f2f427686f116ab77c5b268
Gitweb: http://git.kernel.org/tip/4447ac1195a845b18f2f427686f116ab77c5b268
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:58 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 29 Aug 2017 12:07:28 +0200

x86/idt: Simplify alloc_intr_gate()

The only users of alloc_intr_gate() are hypervisors, which both check the
used_vectors bitmap whether they have allocated the gate already. Move that
check into alloc_intr_gate() and simplify the users.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064959.580830286@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/mshyperv.c | 9 ++-------
arch/x86/kernel/idt.c | 6 +++---
drivers/xen/events/events_base.c | 6 ++----
3 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 70e717f..9fc3265 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -59,13 +59,8 @@ void hyperv_vector_handler(struct pt_regs *regs)
void hv_setup_vmbus_irq(void (*handler)(void))
{
vmbus_handler = handler;
- /*
- * Setup the IDT for hypervisor callback. Prevent reallocation
- * at module reload.
- */
- if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
- hyperv_callback_vector);
+ /* Setup the IDT for hypervisor callback */
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
}

void hv_remove_vmbus_irq(void)
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 8e9318d..b609eac 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -354,7 +354,7 @@ void set_intr_gate(unsigned int n, const void *addr)

void alloc_intr_gate(unsigned int n, const void *addr)
{
- BUG_ON(test_bit(n, used_vectors) || n < FIRST_SYSTEM_VECTOR);
- set_bit(n, used_vectors);
- set_intr_gate(n, addr);
+ BUG_ON(n < FIRST_SYSTEM_VECTOR);
+ if (!test_and_set_bit(n, used_vectors))
+ set_intr_gate(n, addr);
}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 2d43118..1ab4bd1 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -1653,10 +1653,8 @@ void xen_callback_vector(void)
return;
}
pr_info("Xen HVM callback vector for event delivery is enabled\n");
- /* in the restore case the vector has already been allocated */
- if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
- alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
- xen_hvm_callback_vector);
+ alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
+ xen_hvm_callback_vector);
}
}
#else