diff options
Diffstat (limited to 'kc/core/cpu/cpu.c')
| -rw-r--r-- | kc/core/cpu/cpu.c | 107 |
1 files changed, 56 insertions, 51 deletions
diff --git a/kc/core/cpu/cpu.c b/kc/core/cpu/cpu.c index a3205f7..f61ed00 100644 --- a/kc/core/cpu/cpu.c +++ b/kc/core/cpu/cpu.c @@ -15,10 +15,17 @@ #define GDT_ENTRIES 16 #define IDT_ENTRIES 256 -#define CODE_SUPER_SEG_INDEX 1 -#define CODE_USER_SEG_INDEX 2 -#define DATA_SEG_INDEX 3 -#define TASK_SEG_INDEX 4 +enum kernel_segment_indices +{ + NULL_SEG, + CODE64_SUPER_SEG_INDEX, + DATA_SUPER_SEG_INDEX, + CODE32_USER_SEG_INDEX, + DATA32_USER_SEG_INDEX, + CODE64_USER_SEG_INDEX, + DATA64_USER_SEG_INDEX, + TASK64_SEG_INDEX +}; #define EFER_SCE 1 @@ -28,6 +35,13 @@ #define MSR_CSTAR 0xc0000083 #define MSR_SFMASK 0xc0000084 +struct cpu_state +{ + struct segment_descriptor gdt[GDT_ENTRIES]; + struct gate_descriptor idt[IDT_ENTRIES]; + struct task64_segment tss; +}; + static struct segment_descriptor gdt[GDT_ENTRIES]; static struct gate_descriptor idt[IDT_ENTRIES]; static struct task64_segment tss; @@ -64,10 +78,16 @@ static void set_gdt(int index, gdt[index].access = 0xfa; gdt[index].flags_limit16 |= 0xa0; break; - case DATA_SEG: + case CODE32_USER_SEG: + gdt[index].access = 0xfa; + gdt[index].flags_limit16 |= 0xc0; + case DATA_SUPER_SEG: gdt[index].access = 0x92; gdt[index].flags_limit16 |= 0xc0; break; + case DATA_USER_SEG: + gdt[index].access = 0xf2; + gdt[index].flags_limit16 |= 0xc0; case TASK64_SEG: gdt[index].access = 0x89; //TODO: make this cleaner i don't like it @@ -130,8 +150,7 @@ static void gdt_flush(uint16_t code_seg, uint16_t data_seg) "push %q0\n" "lea .Lflush(%%rip), %%rax\n" "push %%rax\n" - // far return, now we're in the code segment - // defined here. + // far return, now we're in the provided code segment "lretq\n" ".Lflush:\n" : @@ -162,41 +181,46 @@ static void gdt_load(struct dtr64 gdtr) ( "lgdt %0\n" : - : "m"(gdtr) + : + "m"(gdtr) ); irq_unlock(rflags); } -static void gdt_init(void) +static struct dtr64 gdt_init(void) { - set_gdt(CODE_SUPER_SEG_INDEX, 0, (uint64_t)-1, CODE64_SUPER_SEG); - set_gdt(CODE_USER_SEG_INDEX, 0, (uint64_t)-1, CODE64_USER_SEG); - set_gdt(DATA_SEG_INDEX, 0, (uint64_t)-1, DATA_SEG); - set_gdt(TASK_SEG_INDEX, (uint64_t)&tss, sizeof(tss) - 1, TASK64_SEG); + set_gdt(CODE64_SUPER_SEG_INDEX, 0, (uint64_t)-1, CODE64_SUPER_SEG); + set_gdt(DATA_SUPER_SEG_INDEX, 0, (uint64_t)-1, DATA_SUPER_SEG); + set_gdt(CODE32_USER_SEG_INDEX, 0, (uint64_t)-1, CODE32_USER_SEG); + set_gdt(DATA32_USER_SEG_INDEX, 0, (uint64_t)-1, DATA_USER_SEG); + set_gdt(CODE64_USER_SEG_INDEX, 0, (uint64_t)-1, CODE64_USER_SEG); + set_gdt(DATA64_USER_SEG_INDEX, 0, (uint64_t)-1, DATA_USER_SEG); + set_gdt(TASK64_SEG_INDEX, (uint64_t)&tss, sizeof(tss) - 1, TASK64_SEG); struct dtr64 gdtr = {sizeof(gdt) - 1, (uint64_t)&gdt}; + gdt_load(gdtr); - gdt_flush(CODE_SUPER_SEG_INDEX, DATA_SEG_INDEX); - gdt_load_task(TASK_SEG_INDEX); -} + gdt_flush(CODE64_SUPER_SEG_INDEX, DATA_SUPER_SEG_INDEX); + gdt_load_task(TASK64_SEG_INDEX); + return gdtr; +} -static void idt_init(void) +static struct dtr64 idt_init(void) { struct dtr64 idtr = {sizeof(idt) - 1, (uint64_t)&idt}; + uint64_t rflags = irq_lock(); __asm__ volatile ( - // can't have interrupts enabled during IDT reload--obviously. - // as with GDT don't re-enable interrupts if they were already - // disabled. - "pushf\n" - "cli\n" "lidt %0\n" - "popf\n" - // much more straightforward than the gdt code. - :: "m"(idtr) + : + : + "m"(idtr) ); + irq_unlock(rflags); + + return idtr; } void cpu_init(void) @@ -207,7 +231,7 @@ void cpu_init(void) //TODO: fix rudimentary syscall stuff. - uint64_t lstar_bits = (uintptr_t)syscall_entry; + uintptr_t lstar_bits = (uintptr_t)syscall_entry; msr_write(MSR_LSTAR, lstar_bits); union @@ -215,10 +239,8 @@ void cpu_init(void) struct { uint32_t eip32; - uint8_t syscall_ss; - uint8_t syscall_cs; - uint8_t sysret_ss; - uint8_t sysret_cs; + uint16_t syscall_cs; + uint16_t sysret_cs; } fields; uint64_t raw; @@ -227,10 +249,8 @@ void cpu_init(void) { { 0, - DATA_SEG_INDEX, - CODE_SUPER_SEG_INDEX, - DATA_SEG_INDEX, - CODE_USER_SEG_INDEX + CODE64_SUPER_SEG_INDEX << 3, + CODE32_USER_SEG_INDEX << 3 | 3 } }; @@ -253,15 +273,10 @@ void exceptions_init(void) void isr_install(int vec, void (*isr)(void), int trap, unsigned ist) { - enum gate_descriptor_type type = INT64_GATE; + enum gate_descriptor_type type = trap ? TRAP64_GATE : INT64_GATE; - if (trap) - { - type = TRAP64_GATE; - } + set_idt(vec, CODE64_SUPER_SEG_INDEX << 3, (uintptr_t)isr, type); - set_idt(vec, CODE_SUPER_SEG_INDEX << 3, (uintptr_t)isr, type); - // an IST greater than 7 is invalid if (ist && ist <= 7) { set_ist(vec, ist); @@ -277,13 +292,3 @@ void ist_install(int ist, void *stack) tss.ist[ist] = (uintptr_t)stack; } -void int_enable(void) -{ - __asm__ ("sti"); -} - -void int_disable(void) -{ - __asm__ ("cli"); -} - |