From 1cc98d32bf344691c73fcc7b64e2ed2755f17ede Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 10 Jul 2021 16:17:07 +0200
Subject: update all segment registers when setting the GDT
not doing that caused interrupts to break on Bochs
---
kernel/gdt.c | 21 ++++++++++++---------
1 file changed, 12 insertions(+), 9 deletions(-)
(limited to 'kernel')
diff --git a/kernel/gdt.c b/kernel/gdt.c
index b76e441..b0d6320 100644
--- a/kernel/gdt.c
+++ b/kernel/gdt.c
@@ -43,7 +43,6 @@ static struct lgdt_arg lgdt_arg; // probably doesn't need to be global
static void gdt_prepare();
static void gdt_load();
-static void gdt_check();
static void gdt_prepare() {
@@ -96,23 +95,27 @@ static void gdt_prepare() {
GDT[SEG_TSS].base_high = (((uint32_t) &TSS) >> 24) & 0xff;
}
+void change_cs(int seg); // temporary
+
static void gdt_load() {
lgdt_arg.limit = sizeof(GDT) - 1;
lgdt_arg.base = (uint32_t) &GDT;
- asm("lgdt (%0)" : : "r" (&lgdt_arg) : "memory");
-
- asm("ltr %%ax" : : "a" (SEG_TSS << 3 | 3) : "memory");
-}
+ asm("lgdt (%0)"
+ : : "r" (&lgdt_arg) : "memory");
+ asm("ltr %%ax"
+ : : "a" (SEG_TSS << 3 | 3) : "memory");
-static void gdt_check() {
- // note: this only checks the r0data segment,
- // it's far from a comprehensive test
+ // update all segment registers
+ change_cs(SEG_r0code << 3);
asm("mov %0, %%ds;"
+ "mov %0, %%ss;"
+ "mov %0, %%es;"
+ "mov %0, %%fs;"
+ "mov %0, %%gs;"
: : "r" (SEG_r0data << 3) : "memory");
}
void gdt_init() {
gdt_prepare();
gdt_load();
- gdt_check();
}
--
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