Added memory management using paging

This was quite a roller-coaster and most things are slower now, but it works and is way more secure. I still need to implement things like shared memory for the WM/GUI system but other than that everything is supported.

1 files changed, 29 insertions, 10 deletions

diff --git a/libc/cpu.c b/libc/cpu.c
index 08e742c..8ca4d27 100644
--- a/libc/cpu.c
+++ b/libc/cpu.c
@@ -70,34 +70,52 @@ void cpu_print(void)
 	printf("CPU vendor: %s\n", cpu_string(buf));
 }
 
-static u32 cr0_get(void)
+u32 cr0_get(void)
 {
 	u32 cr0;
 	__asm__ volatile("movl %%cr0, %%eax" : "=a"(cr0));
 	return cr0;
 }
 
-static void cr0_set(u32 cr0)
+void cr0_set(u32 cr0)
 {
 	__asm__ volatile("movl %%eax, %%cr0" ::"a"(cr0));
 }
 
-static u32 cr4_get(void)
+u32 cr3_get(void)
+{
+	u32 cr3;
+	__asm__ volatile("movl %%cr0, %%eax" : "=a"(cr3));
+	return cr3;
+}
+
+void cr3_set(u32 cr3)
+{
+	__asm__ volatile("movl %%eax, %%cr3" ::"a"(cr3));
+}
+
+u32 cr4_get(void)
 {
 	u32 cr4;
 	__asm__ volatile("movl %%cr4, %%eax" : "=a"(cr4));
 	return cr4;
 }
 
-static void cr4_set(u32 cr4)
+void cr4_set(u32 cr4)
 {
 	__asm__ volatile("movl %%eax, %%cr4" ::"a"(cr4));
 }
 
-static u32 cpu_features = 0;
-static u8 cpu_has_feature(u32 feature)
+static u32 cpu_cfeatures = 0;
+u8 cpu_has_cfeature(enum cpuid_features feature)
+{
+	return (cpu_cfeatures & feature) != 0;
+}
+
+static u32 cpu_dfeatures = 0;
+u8 cpu_has_dfeature(enum cpuid_features feature)
 {
-	return (cpu_features & feature) != 0;
+	return (cpu_dfeatures & feature) != 0;
 }
 
 static void fpu_handler(struct regs *r)
@@ -116,8 +134,9 @@ void cpu_enable_features(void)
 {
 	u32 a, b, c, d;
 	cpuid(CPUID_FEATURES, &a, &b, &c, &d);
-	cpu_features = d;
-	if (cpu_has_feature(CPUID_FEAT_EDX_SSE)) {
+	cpu_cfeatures = c;
+	cpu_dfeatures = d;
+	if (cpu_has_dfeature(CPUID_FEAT_EDX_SSE)) {
 		cr0_set(cr0_get() & ~(1 << 2));
 		cr0_set(cr0_get() | (1 << 1));
 		cr4_set(cr4_get() | (3 << 9));
@@ -125,7 +144,7 @@ void cpu_enable_features(void)
 		panic("No SSE support!\n");
 	}
 
-	if (cpu_has_feature(CPUID_FEAT_EDX_FPU)) {
+	if (cpu_has_dfeature(CPUID_FEAT_EDX_FPU)) {
 		__asm__ volatile("fninit");
 		__asm__ volatile("fxsave %0" : "=m"(fpu_state));
 		irq_install_handler(7, fpu_handler);