X-Git-Url: https://pd.if.org/git/?p=zos;a=blobdiff_plain;f=idt.s;fp=idt.s;h=10c95d515cd8bcd9cb5d66fb5c372555c684b943;hp=0000000000000000000000000000000000000000;hb=120ce15fac48f7aceac231ea3fcdcade26093e7b;hpb=4bfc87356b0316256d2eaf91497973dbddcd2db7

diff --git a/idt.s b/idt.s
new file mode 100644
index 0000000..10c95d5
--- /dev/null
+++ b/idt.s
@@ -0,0 +1,210 @@
+struc idt_entry
+.handler_low:	resw 1
+.selector:	resw 1
+.ist:		resb 1
+.flags:		resb 1
+.handler_high:	resw 1
+.handler_highest:	resd 1
+.reserved:	resd 1
+endstruc
+
+align 16
+
+global set_idt_entry:function
+
+;void set_idt_entry(
+;	struct idt_entry *entry, rdi
+;	uintptr_t handler,       rsi
+;	uint16_t selector,       rdx
+;	uint8_t flags,		 rcx
+;	uint8_t ist              r8
+
+set_idt_entry:
+	mov [rdi + idt_entry.flags], cl
+	mov [rdi + idt_entry.ist], r8b
+	mov [rdi + idt_entry.selector], dx
+	mov [rdi + idt_entry.handler_low], si
+	shr rsi, 16
+	mov [rdi + idt_entry.handler_high], si
+	shr rsi, 16
+	mov [rdi + idt_entry.handler_highest], esi
+	mov [rdi + idt_entry.reserved], dword 0x0
+
+global load_idt:function
+
+load_idt:
+;	size_t limit = sizeof(struct idt_entry) * length - 1;
+	shl rsi, 4
+	sub rsi, 1
+
+	sub rsp, 10
+	mov [rsp], si
+	mov [rsp + 2], rdi
+	lidt [rsp]
+	add rsp, 10
+	ret
+
+section .text
+
+extern interrupt_handler
+extern global_errno
+extern printk
+
+%macro makeisr 2
+global isr%1:function
+isr%1:
+	push %2 ; err_code
+	push %1 ; int_no
+	jmp interrupt_handler_prepare
+%endmacro
+
+%macro makeisr 1
+global isr%1:function
+isr%1:
+	; error code pushed by processor
+	push %1 ; int_no
+	jmp interrupt_handler_prepare
+%endmacro
+
+%macro makeirq 2
+global irq%1:function
+irq%1:
+	push 0 ; err_code
+	push %2 ; int_no
+	jmp interrupt_handler_prepare
+%endmacro
+
+; create isr 0-7, which need an error code pushed
+%assign i 0
+%rep 8
+
+makeisr i,0 
+
+%assign i i+1
+%endrep
+
+makeisr 8
+makeisr 9,0
+makeisr 10
+makeisr 11
+makeisr 12
+makeisr 13
+makeisr 14
+
+; make isr 15-31
+%assign i 15
+%rep 17
+makeisr i,0 
+%assign i i+1
+%endrep
+
+; make irqs
+%assign i 32
+%assign j 0
+%rep 16
+makeirq j,i
+%assign i i+1
+%assign j j+1
+%endrep
+
+; make remaining interrupts
+%assign i 48
+%rep 208
+makeisr i,0 
+%assign i i+1
+%endrep
+
+interrupt_handler_prepare:
+
+	push r15
+	push r14
+	push r13
+	push r12
+	push r11
+	push r10
+	push r9
+	push r8
+	push rax
+	push rcx
+	push rdx
+	push rbx
+	push rsp
+	push rbp
+	push rsi
+	push rdi
+
+	; CR2 for page faults, always push for consistent frame
+	mov rbp, cr2
+	push rbp
+
+	mov eax, [qword global_errno]
+	push rax
+
+	mov rdi, rsp ; context stack frame pointer
+	mov rbx, rsp ; rbx is preserved by the abi, so save it
+	and rsp, 0xFFFFFFF0 ; should be sign extended
+	call interrupt_handler
+	mov rsp, rbx ; restore the stack
+
+load_interrupted_registers:
+	; Restore the previous kernel errno.
+	pop rax
+	mov [qword global_errno], eax
+
+	add rsp, 8 ; remove CR2
+
+	pop rdi
+	pop rsi
+	pop rbp
+	add rsp, 8 ; skip rsp
+	pop rbx
+	pop rdx
+	pop rcx
+	pop rax
+	pop r8
+	pop r9
+	pop r10
+	pop r11
+	pop r12
+	pop r13
+	pop r14
+	pop r15
+
+	; Remove int_no and err_code
+	add rsp, 16
+
+	iretq
+;.size interrupt_handler_prepare, . - interrupt_handler_prepare
+
+global interrupt_handler_null:function
+
+align 16
+interrupt_handler_null:
+	iretq
+;.size interrupt_handler_null, . - interrupt_handler_null
+
+rfprintf:  db 'rflags : %llx', 10, 0
+csprintf:  db 'cs     : %hx', 10, 0
+ripprintf: db 'rip    : %llx', 10, 0
+rspprintf: db 'rsp    : %llx', 10, 0
+ssprintf:  db 'ss     : %hx', 10, 0
+csvprintf: db 'gdt    : %016llx', 10, 0
+
+global interrupts_enabled:function
+interrupts_enabled:
+	pushf
+	pop rax
+	shr rax, 9
+	and rax, 0x1
+	ret
+
+global enable_interrupts:function
+enable_interrupts:
+	sti
+	ret
+
+global disable_interrupts:function
+disable_interrupts:
+	cli
+	ret
+