linux-kernel - [patch 3/5] x86/idt: Use proper constants for table sizes

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Date:   Thu, 28 May 2020 16:53:18 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org
Subject: [patch 3/5] x86/idt: Use proper constants for table sizes

Use the actual struct size to calculate the IDT table sizes instead of two
different hardcoded values.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/idt.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -51,6 +51,8 @@ struct idt_data {
 #define TSKG(_vector, _gdt)				\
 	G(_vector, NULL, DEFAULT_STACK, GATE_TASK, DPL0, _gdt << 3)
 
+#define IDT_TABLE_SIZE		(IDT_ENTRIES * sizeof(gate_desc))
+#define IDT_DEBUG_TABLE_SIZE	(16 * sizeof(gate_desc))
 
 static bool idt_setup_done __initdata;
 
@@ -176,7 +178,7 @@ static const __initconst struct idt_data
 gate_desc idt_table[IDT_ENTRIES] __page_aligned_bss;
 
 struct desc_ptr idt_descr __ro_after_init = {
-	.size		= (IDT_ENTRIES * 2 * sizeof(unsigned long)) - 1,
+	.size		= IDT_TABLE_SIZE - 1,
 	.address	= (unsigned long) idt_table,
 };
 
@@ -202,7 +204,7 @@ static const __initconst struct idt_data
  * stack set to DEFAULT_STACK (0). Required for NMI trap handling.
  */
 const struct desc_ptr debug_idt_descr = {
-	.size		= IDT_ENTRIES * 16 - 1,
+	.size		= IDT_DEBUG_TABLE_SIZE - 1,
 	.address	= (unsigned long) debug_idt_table,
 };
 #endif
@@ -304,9 +306,10 @@ void __init idt_setup_ist_traps(void)
  */
 void __init idt_setup_debugidt_traps(void)
 {
-	memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
+	memcpy(&debug_idt_table, &idt_table, IDT_DEBUG_TABLE_SIZE);
 
-	idt_setup_from_table(debug_idt_table, dbg_idts, ARRAY_SIZE(dbg_idts), false);
+	idt_setup_from_table(debug_idt_table, dbg_idts, ARRAY_SIZE(dbg_idts),
+			     false);
 }
 #endif