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Kernel: GDTR and IDTR limits should be table size - 1.

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This commit is contained in:
Andreas Kling 2019-05-17 18:16:22 +02:00
parent 0d77aa841a
commit 923e587283
1 changed files with 11 additions and 12 deletions
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23
Kernel/i386.cpp
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@ -12,7 +12,7 @@
//#define PAGE_FAULT_DEBUG
struct [[gnu::packed]] DescriptorTablePointer {
word size;
word limit;
void* address;
};
@ -25,7 +25,7 @@ static IRQHandler** s_irq_handler;
static Vector<word>* s_gdt_freelist;
static word s_gdtLength;
static word s_gdt_length;
word gdt_alloc_entry()
{
@ -323,9 +323,8 @@ static void write_raw_gdt_entry(word selector, dword low, dword high)
s_gdt[i].low = low;
s_gdt[i].high = high;
if (i > s_gdtLength) {
s_gdtr.size = (s_gdtLength + 1) * 8;
}
if (i > s_gdt_length)
s_gdtr.limit = (s_gdt_length + 1) * 8 - 1;
}
void write_gdt_entry(word selector, Descriptor& descriptor)
@ -342,23 +341,23 @@ Descriptor& get_gdt_entry(word selector)
void flush_gdt()
{
s_gdtr.address = s_gdt;
s_gdtr.size = (s_gdtLength * 8) - 1;
asm("lgdt %0"::"m"(s_gdtr));
s_gdtr.limit = (s_gdt_length * 8) - 1;
asm("lgdt %0"::"m"(s_gdtr):"memory");
}
void gdt_init()
{
s_gdt = static_cast<Descriptor*>(kmalloc_eternal(sizeof(Descriptor) * 256));
s_gdtLength = 5;
s_gdt_length = 5;
s_gdt_freelist = new Vector<word>();
s_gdt_freelist->ensure_capacity(256);
for (size_t i = s_gdtLength; i < 256; ++i)
for (size_t i = s_gdt_length; i < 256; ++i)
s_gdt_freelist->append(i * 8);
s_gdtLength = 256;
s_gdt_length = 256;
s_gdtr.address = s_gdt;
s_gdtr.size = (s_gdtLength * 8) - 1;
s_gdtr.limit = (s_gdt_length * 8) - 1;
write_raw_gdt_entry(0x0000, 0x00000000, 0x00000000);
write_raw_gdt_entry(0x0008, 0x0000ffff, 0x00cf9a00);
@ -424,7 +423,7 @@ void idt_init()
s_idt = static_cast<Descriptor*>(kmalloc_eternal(sizeof(Descriptor) * 256));
s_idtr.address = s_idt;
s_idtr.size = 0x100 * 8;
s_idtr.limit = 0x100 * 8 - 1;
for (byte i = 0xff; i > 0x10; --i)
register_interrupt_handler(i, unimp_trap);