From: Matthias Kruk <m@m10k.eu>
Date: Wed, 25 Sep 2019 09:57:58 +0000 (+0900)
Subject: Fix a bug in task_switch() that would cause the TSS update to be skipped
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=8ce2011aa84b49f5db922aaa5750b27bbf3484b7;p=corax

Fix a bug in task_switch() that would cause the TSS update to be skipped
---

diff --git a/kernel/arch/task.S b/kernel/arch/task.S
index 513c8a2..b78b2af 100644
--- a/kernel/arch/task.S
+++ b/kernel/arch/task.S
@@ -36,7 +36,7 @@
 task_prepare:
 	/*
 	 * int task_prepare(struct task*, u32_t cr3, u32_t eip,
-	 *                  u32_t esp, u32_t priv)
+	 *                  u32_t esp0, u32_t esp, u32_t priv)
 	 *
 	 *  priv  = 24(%esp)
 	 *  esp   = 20(%esp)
@@ -164,7 +164,7 @@ task_switch:
 	ret
 
 	/* put the task's ESP0 into the TSS */
-	movl	OFFSET_ESP0(%edi), %ecx
+2:	movl	OFFSET_ESP0(%edi), %ecx
 	movl	%ecx, CPU_ESP0(%eax)
 	movl	$KERNEL_DATA, CPU_SS0(%eax)
 
@@ -173,14 +173,14 @@ task_switch:
 	 * set the segment registers accordingly
 	 */
 	/*
-	movl	$KERNEL_CODE, CPU_CS(%eax)
-	movl	$KERNEL_DATA, CPU_DS(%eax)
-	movl	$KERNEL_DATA, CPU_ES(%eax)
-	movl	$KERNEL_DATA, CPU_FS(%eax)
-	movl	$KERNEL_DATA, CPU_GS(%eax)
+	movl	$USER_CODE, CPU_CS(%eax)
+	movl	$USER_DATA, CPU_DS(%eax)
+	movl	$USER_DATA, CPU_ES(%eax)
+	movl	$USER_DATA, CPU_FS(%eax)
+	movl	$USER_DATA, CPU_GS(%eax)
+	movl	$USER_DATA, CPU_SS(%eax)
 	*/
-
-2:	movl	OFFSET_CR3(%edi), %ecx
+	movl	OFFSET_CR3(%edi), %ecx
 
 	/* check if we can avoid writing to cr3, which would clear the TLB */
 	movl	%cr3, %edx