[tip: x86/entry] x86/idt: Cleanup trap_init()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the x86/entry branch of tip:

Commit-ID:     88dbb6cfb9be0eaaa95c15a4b6d7f49044a2e1b7
Gitweb:        https://git.kernel.org/tip/88dbb6cfb9be0eaaa95c15a4b6d7f49044a2e1b7
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Thu, 28 May 2020 16:53:19 +02:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Sat, 30 May 2020 11:50:12 +02:00

x86/idt: Cleanup trap_init()

No point in having all the IDT cruft in trap_init(). Move it into the IDT
code and fixup the comments.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200528145522.992376498@xxxxxxxxxxxxx

---
 arch/x86/kernel/idt.c   | 18 ++++++++++++++++++
 arch/x86/kernel/traps.c |  9 ---------
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index b6e1a87..902cdd0 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -4,6 +4,7 @@
  */
 #include <linux/interrupt.h>
 
+#include <asm/cpu_entry_area.h>
 #include <asm/traps.h>
 #include <asm/proto.h>
 #include <asm/desc.h>
@@ -281,6 +282,19 @@ void __init idt_setup_ist_traps(void)
 }
 #endif
 
+static void __init idt_map_in_cea(void)
+{
+	/*
+	 * Set the IDT descriptor to a fixed read-only location in the cpu
+	 * entry area, so that the "sidt" instruction will not leak the
+	 * location of the kernel, and to defend the IDT against arbitrary
+	 * memory write vulnerabilities.
+	 */
+	cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table),
+		    PAGE_KERNEL_RO);
+	idt_descr.address = CPU_ENTRY_AREA_RO_IDT;
+}
+
 /**
  * idt_setup_apic_and_irq_gates - Setup APIC/SMP and normal interrupt gates
  */
@@ -307,6 +321,10 @@ void __init idt_setup_apic_and_irq_gates(void)
 		set_intr_gate(i, entry);
 	}
 #endif
+	/* Map IDT into CPU entry area and reload it. */
+	idt_map_in_cea();
+	load_idt(&idt_descr);
+
 	idt_setup_done = true;
 }
 
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 79af913..5566fe5 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -1056,15 +1056,6 @@ void __init trap_init(void)
 	idt_setup_traps();
 
 	/*
-	 * Set the IDT descriptor to a fixed read-only location, so that the
-	 * "sidt" instruction will not leak the location of the kernel, and
-	 * to defend the IDT against arbitrary memory write vulnerabilities.
-	 * It will be reloaded in cpu_init() */
-	cea_set_pte(CPU_ENTRY_AREA_RO_IDT_VADDR, __pa_symbol(idt_table),
-		    PAGE_KERNEL_RO);
-	idt_descr.address = CPU_ENTRY_AREA_RO_IDT;
-
-	/*
 	 * Should be a barrier for any external CPU state:
 	 */
 	cpu_init();