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Subject[tip: x86/entry] x86/idt: Cleanup trap_init()
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@linutronix.de>
AuthorDate: Thu, 28 May 2020 16:53:19 +02:00
Committer: Thomas Gleixner <tglx@linutronix.de>
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@linutronix.de>
Link: https://lkml.kernel.org/r/20200528145522.992376498@linutronix.de

---
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();
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