[tip:x86/apic] x86/idt: Hide set_intr_gate()

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

Commit-ID: facaa3e3c813848e6b49ee37a42a3688832e63cd
Gitweb: http://git.kernel.org/tip/facaa3e3c813848e6b49ee37a42a3688832e63cd
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Mon, 28 Aug 2017 08:47:59 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 29 Aug 2017 12:07:29 +0200

x86/idt: Hide set_intr_gate()

set_intr_gate() is an internal function of the IDT code. The only user left
is the KVM code which replaces the pagefault handler eventually.

Provide an explicit update_intr_gate() function and make set_intr_gate()
static. While at it replace the magic number 14 in the KVM code with the
proper trap define.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
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: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064959.663008004@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/desc.h | 2 +-
arch/x86/kernel/idt.c | 33 ++++++++++++++++++++-------------
arch/x86/kernel/kvm.c | 2 +-
3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index 33f84f2..1a2ba36 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -390,7 +390,7 @@ static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
desc->limit1 = (limit >> 16) & 0xf;
}

-void set_intr_gate(unsigned int n, const void *addr);
+void update_intr_gate(unsigned int n, const void *addr);
void alloc_intr_gate(unsigned int n, const void *addr);

extern unsigned long used_vectors[];
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index b609eac..61b490c 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -225,6 +225,22 @@ idt_setup_from_table(gate_desc *idt, const struct idt_data *t, int size, bool sy
}
}

+static void set_intr_gate(unsigned int n, const void *addr)
+{
+ struct idt_data data;
+
+ BUG_ON(n > 0xFF);
+
+ memset(&data, 0, sizeof(data));
+ data.vector = n;
+ data.addr = addr;
+ data.segment = __KERNEL_CS;
+ data.bits.type = GATE_INTERRUPT;
+ data.bits.p = 1;
+
+ idt_setup_from_table(idt_table, &data, 1, false);
+}
+
/**
* idt_setup_early_traps - Initialize the idt table with early traps
*
@@ -336,20 +352,11 @@ void idt_invalidate(void *addr)
load_idt(&idt);
}

-void set_intr_gate(unsigned int n, const void *addr)
+void __init update_intr_gate(unsigned int n, const void *addr)
{
- struct idt_data data;
-
- BUG_ON(n > 0xFF);
-
- memset(&data, 0, sizeof(data));
- data.vector = n;
- data.addr = addr;
- data.segment = __KERNEL_CS;
- data.bits.type = GATE_INTERRUPT;
- data.bits.p = 1;
-
- idt_setup_from_table(idt_table, &data, 1, false);
+ if (WARN_ON_ONCE(!test_bit(n, used_vectors)))
+ return;
+ set_intr_gate(n, addr);
}

void alloc_intr_gate(unsigned int n, const void *addr)
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 6ed9242..874827b 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -455,7 +455,7 @@ static int kvm_cpu_down_prepare(unsigned int cpu)

static void __init kvm_apf_trap_init(void)
{
- set_intr_gate(14, async_page_fault);
+ update_intr_gate(X86_TRAP_PF, async_page_fault);
}

void __init kvm_guest_init(void)