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Added IDT driver

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This commit is contained in:
ice-bit
2019-07-05 12:32:04 +02:00
parent 14ee39a515
commit 1aa6963e84
7 changed files with 239 additions and 16 deletions
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26
kernel/drivers/gdt.h
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@@ -12,7 +12,7 @@
* GDT(Global Descriptor Table) is a complex data structure used in x86 systems
* to define memory areas.
* Technically speaking GDT is formed by an array of 8-bytes segment descriptors,
* the first descriptor of the GDT is always a NULL one and CANNNOT be used to allocate
* the first descriptor of the GDT is always a NULL one and CANNOT be used to allocate
* memory; so we need at least two descriptors(plus the null descriptor) to successfully allocate
* data on our memory.
* In x86 architecture there're two methods to provide virtual memory: Segmentation and Paging:
@@ -34,14 +34,14 @@
/* Those values were taken from Intel's developer manual */
// GDT fields
#define GDT_BASE 0x00000000
#define GDT_BASE 0x00000000
#define GDT_LIMIT 0xFFFFFFFF
// GDT granularity
#define GDT_SEGMENT_LENGTH 0xF
#define GDT_SEGMENT_LENGTH 0xF
#define GDT_OPERAND_SIZE_16 0
#define GDT_OPERAND_SIZE_32 1
#define GDT_GRANULARITY_1K 0
#define GDT_GRANULARITY_4K 1
#define GDT_GRANULARITY_1K 0
#define GDT_GRANULARITY_4K 1
// GDT access type fields
#define GDT_DATA_TYPE_READ_ONLY 0x0
#define GDT_DATA_TYPE_READ_ONLY_ACCESSED 0x1
@@ -82,10 +82,10 @@
* P: is segment present? (bool)
*/
struct gdt_access {
uint8_t type:4; // 4 Byte
uint8_t dt:1; // 1 Byte
uint8_t dpl:2; // 2 Byte
uint8_t p:1; // 1 Byte
uint8_t type: 4; // 4 Byte
uint8_t dt: 1; // 1 Byte
uint8_t dpl: 2; // 2 Byte
uint8_t p: 1; // 1 Byte
}__attribute__((packed));
typedef struct gdt_access gdt_access_t;
@@ -98,10 +98,10 @@ typedef struct gdt_access gdt_access_t;
* G: granularity (0 = 1 Byte, 1 = 4KiB)
*/
struct gdt_granularity {
uint8_t seglen:4;
uint8_t zero:2;
uint8_t d:1;
uint8_t g:1;
uint8_t seglen: 4;
uint8_t zero: 2;
uint8_t d: 1;
uint8_t g: 1;
}__attribute__((packed));
typedef struct gdt_granularity gdt_gran_t;