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- #ifndef __KERN_MM_MMU_H__
- #define __KERN_MM_MMU_H__
-
- /* Eflags register */
- #define FL_CF 0x00000001 // Carry Flag
- #define FL_PF 0x00000004 // Parity Flag
- #define FL_AF 0x00000010 // Auxiliary carry Flag
- #define FL_ZF 0x00000040 // Zero Flag
- #define FL_SF 0x00000080 // Sign Flag
- #define FL_TF 0x00000100 // Trap Flag
- #define FL_IF 0x00000200 // Interrupt Flag
- #define FL_DF 0x00000400 // Direction Flag
- #define FL_OF 0x00000800 // Overflow Flag
- #define FL_IOPL_MASK 0x00003000 // I/O Privilege Level bitmask
- #define FL_IOPL_0 0x00000000 // IOPL == 0
- #define FL_IOPL_1 0x00001000 // IOPL == 1
- #define FL_IOPL_2 0x00002000 // IOPL == 2
- #define FL_IOPL_3 0x00003000 // IOPL == 3
- #define FL_NT 0x00004000 // Nested Task
- #define FL_RF 0x00010000 // Resume Flag
- #define FL_VM 0x00020000 // Virtual 8086 mode
- #define FL_AC 0x00040000 // Alignment Check
- #define FL_VIF 0x00080000 // Virtual Interrupt Flag
- #define FL_VIP 0x00100000 // Virtual Interrupt Pending
- #define FL_ID 0x00200000 // ID flag
-
- /* Application segment type bits */
- #define STA_X 0x8 // Executable segment
- #define STA_E 0x4 // Expand down (non-executable segments)
- #define STA_C 0x4 // Conforming code segment (executable only)
- #define STA_W 0x2 // Writeable (non-executable segments)
- #define STA_R 0x2 // Readable (executable segments)
- #define STA_A 0x1 // Accessed
-
- /* System segment type bits */
- #define STS_T16A 0x1 // Available 16-bit TSS
- #define STS_LDT 0x2 // Local Descriptor Table
- #define STS_T16B 0x3 // Busy 16-bit TSS
- #define STS_CG16 0x4 // 16-bit Call Gate
- #define STS_TG 0x5 // Task Gate / Coum Transmitions
- #define STS_IG16 0x6 // 16-bit Interrupt Gate
- #define STS_TG16 0x7 // 16-bit Trap Gate
- #define STS_T32A 0x9 // Available 32-bit TSS
- #define STS_T32B 0xB // Busy 32-bit TSS
- #define STS_CG32 0xC // 32-bit Call Gate
- #define STS_IG32 0xE // 32-bit Interrupt Gate
- #define STS_TG32 0xF // 32-bit Trap Gate
-
- /* Gate descriptors for interrupts and traps */
- struct gatedesc {
- unsigned gd_off_15_0 : 16; // low 16 bits of offset in segment
- unsigned gd_ss : 16; // segment selector
- unsigned gd_args : 5; // # args, 0 for interrupt/trap gates
- unsigned gd_rsv1 : 3; // reserved(should be zero I guess)
- unsigned gd_type : 4; // type(STS_{TG,IG32,TG32})
- unsigned gd_s : 1; // must be 0 (system)
- unsigned gd_dpl : 2; // descriptor(meaning new) privilege level
- unsigned gd_p : 1; // Present
- unsigned gd_off_31_16 : 16; // high bits of offset in segment
- };
-
- /* *
- * Set up a normal interrupt/trap gate descriptor
- * - istrap: 1 for a trap (= exception) gate, 0 for an interrupt gate
- * - sel: Code segment selector for interrupt/trap handler
- * - off: Offset in code segment for interrupt/trap handler
- * - dpl: Descriptor Privilege Level - the privilege level required
- * for software to invoke this interrupt/trap gate explicitly
- * using an int instruction.
- * */
- #define SETGATE(gate, istrap, sel, off, dpl) { \
- (gate).gd_off_15_0 = (uint32_t)(off) & 0xffff; \
- (gate).gd_ss = (sel); \
- (gate).gd_args = 0; \
- (gate).gd_rsv1 = 0; \
- (gate).gd_type = (istrap) ? STS_TG32 : STS_IG32; \
- (gate).gd_s = 0; \
- (gate).gd_dpl = (dpl); \
- (gate).gd_p = 1; \
- (gate).gd_off_31_16 = (uint32_t)(off) >> 16; \
- }
-
- /* Set up a call gate descriptor */
- #define SETCALLGATE(gate, ss, off, dpl) { \
- (gate).gd_off_15_0 = (uint32_t)(off) & 0xffff; \
- (gate).gd_ss = (ss); \
- (gate).gd_args = 0; \
- (gate).gd_rsv1 = 0; \
- (gate).gd_type = STS_CG32; \
- (gate).gd_s = 0; \
- (gate).gd_dpl = (dpl); \
- (gate).gd_p = 1; \
- (gate).gd_off_31_16 = (uint32_t)(off) >> 16; \
- }
-
- /* segment descriptors */
- struct segdesc {
- unsigned sd_lim_15_0 : 16; // low bits of segment limit
- unsigned sd_base_15_0 : 16; // low bits of segment base address
- unsigned sd_base_23_16 : 8; // middle bits of segment base address
- unsigned sd_type : 4; // segment type (see STS_ constants)
- unsigned sd_s : 1; // 0 = system, 1 = application
- unsigned sd_dpl : 2; // descriptor Privilege Level
- unsigned sd_p : 1; // present
- unsigned sd_lim_19_16 : 4; // high bits of segment limit
- unsigned sd_avl : 1; // unused (available for software use)
- unsigned sd_rsv1 : 1; // reserved
- unsigned sd_db : 1; // 0 = 16-bit segment, 1 = 32-bit segment
- unsigned sd_g : 1; // granularity: limit scaled by 4K when set
- unsigned sd_base_31_24 : 8; // high bits of segment base address
- };
-
- #define SEG_NULL \
- (struct segdesc){0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
-
- #define SEG(type, base, lim, dpl) \
- (struct segdesc){ \
- ((lim) >> 12) & 0xffff, (base) & 0xffff, \
- ((base) >> 16) & 0xff, type, 1, dpl, 1, \
- (unsigned)(lim) >> 28, 0, 0, 1, 1, \
- (unsigned) (base) >> 24 \
- }
-
- #define SEG16(type, base, lim, dpl) \
- (struct segdesc){ \
- (lim) & 0xffff, (base) & 0xffff, \
- ((base) >> 16) & 0xff, type, 1, dpl, 1, \
- (unsigned) (lim) >> 16, 0, 0, 1, 0, \
- (unsigned) (base) >> 24 \
- }
-
- /* task state segment format (as described by the Pentium architecture book) */
- struct taskstate {
- uint32_t ts_link; // old ts selector
- uintptr_t ts_esp0; // stack pointers and segment selectors
- uint16_t ts_ss0; // after an increase in privilege level
- uint16_t ts_padding1;
- uintptr_t ts_esp1;
- uint16_t ts_ss1;
- uint16_t ts_padding2;
- uintptr_t ts_esp2;
- uint16_t ts_ss2;
- uint16_t ts_padding3;
- uintptr_t ts_cr3; // page directory base
- uintptr_t ts_eip; // saved state from last task switch
- uint32_t ts_eflags;
- uint32_t ts_eax; // more saved state (registers)
- uint32_t ts_ecx;
- uint32_t ts_edx;
- uint32_t ts_ebx;
- uintptr_t ts_esp;
- uintptr_t ts_ebp;
- uint32_t ts_esi;
- uint32_t ts_edi;
- uint16_t ts_es; // even more saved state (segment selectors)
- uint16_t ts_padding4;
- uint16_t ts_cs;
- uint16_t ts_padding5;
- uint16_t ts_ss;
- uint16_t ts_padding6;
- uint16_t ts_ds;
- uint16_t ts_padding7;
- uint16_t ts_fs;
- uint16_t ts_padding8;
- uint16_t ts_gs;
- uint16_t ts_padding9;
- uint16_t ts_ldt;
- uint16_t ts_padding10;
- uint16_t ts_t; // trap on task switch
- uint16_t ts_iomb; // i/o map base address
- };
-
- #endif /* !__KERN_MM_MMU_H__ */
-
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