i386: re-implement the IDT setup

src/arch/i386/idt.S

@@ -13,22 +13,26 @@
 .type __arch_setidt, @function
 #endif
 __arch_setidt:
-	lea	idt, %ecx
+	lea	idt_descriptor, %ecx
+
 	/* set the offset of the IDT */
 	mov	0x4(%esp), %eax
 	mov	%eax, 0x2(%ecx)
+
 	/* set the size of the IDT */
 	mov	0x8(%esp), %eax
 	dec	%eax
 	mov	%ax, (%ecx)
+
 	/* load the IDT */
-	lidt	(%ecx)
+	lidt	(idt_descriptor)
+
 	ret
 
 
 /* bss */
 .section .bss
 .align 16
-idt:
+idt_descriptor:
 .skip 2		/* size */
 .skip 4		/* offset */

src/arch/i386/idt.h

@@ -12,15 +12,28 @@
 
 /* public */
 /* types */
-typedef struct _IDT
+typedef struct _IDT IDT;
+
+typedef struct _IDTEntry
 {
-	uint32_t base;
+	uint16_t offsetl;
 	uint16_t selector;
-	uint8_t flags;
+	uint8_t __padding;
-} IDT;
+	uint8_t type:4;
+	uint8_t flags:4;
+	uint16_t offseth;
+} IDTEntry;
+
+
+/* constants */
+# define IDT_FLAG_PRESENT	0x8
+# define IDT_FLAG_RING(level)	((level) << 1)
+
+# define IDT_TYPE_INT_GATE	0xe
+# define IDT_TYPE_TRAP_GATE	0xf
 
 
 /* prototypes */
-int _arch_setidt(IDT const * idt, size_t count);
+IDT * idt_init(void);
 
 #endif /* !UKERNEL_ARCH_I386_IDT_H */

src/kernel/idt.c

@@ -1,58 +1,7 @@
 /* $Id$ */
-/* Copyright (c) 2018 Pierre Pronchery <khorben@defora.org> */
+/* Copyright (c) 2018-2025 Pierre Pronchery <khorben@defora.org> */
 /* This file is part of DeforaOS uKernel */
 
 
 
-#if defined(__amd64__) || defined(__i386__)
+#include "../loader/idt.c"
-# include <stdint.h>
-# include <string.h>
-# include <errno.h>
-# include "arch/i386/idt.h"
-
-
-/* prototypes */
-extern void __arch_setidt(uint8_t * buf, size_t count);
-
-
-/* variables */
-/* FIXME correct the size */
-static uint8_t _buf[65536];
-
-
-/* functions */
-/* arch_setidt */
-int _arch_setidt(IDT const * idt, size_t count)
-{
-	uint8_t * buf = _buf;
-	size_t i;
-	IDT const * t;
-
-	memset(&_buf, 0, sizeof(_buf));
-	/* check for errors */
-	if(/* count == 0 ||*/ count > sizeof(_buf) / sizeof(*idt))
-	{
-		errno = ERANGE;
-		return -1;
-	}
-	for(i = 0; i < count; i++)
-	{
-		t = &idt[i];
-		buf = &_buf[sizeof(t) * i];
-		/* encode the address */
-		buf[0] = (t->base >> 8) & 0xff;
-		buf[1] = t->base & 0xff;
-		buf[6] = (t->base >> 24) & 0xff;
-		buf[7] = (t->base >> 16) & 0xff;
-		/* selector */
-		buf[2] = (t->selector >> 8) & 0xff;
-		buf[3] = t->selector & 0xff;
-		/* padding */
-		buf[4] = 0x0;
-		/* flags */
-		buf[5] = t->flags;
-	}
-	__arch_setidt(_buf, count);
-	return 0;
-}
-#endif

src/kernel/multiboot.c

@@ -33,10 +33,6 @@ static const GDTTable _gdt_4gb[2] =
 	{ 0x00000000, 0xffffffff, GDT_PROT_READ | GDT_PROT_WRITE }
 };
 
-static const IDT _idt[] =
-{
-};
-
 
 /* public */
 /* functions */
@@ -113,7 +109,7 @@ int multiboot(const ukMultibootInfo * mi)
 	}
 
 	/* setup the IDT */
-	if(_arch_setidt(_idt, sizeof(_idt) / sizeof(*_idt)) != 0)
+	if(idt_init() == NULL)
 	{
 		puts("Could not setup the IDT");
 		return 5;

src/kernel/project.conf

@@ -42,6 +42,12 @@ depends=../common/crti.S,../arch/amd64/crti.S,../arch/i386/crti.S
 [crtn.S]
 depends=../common/crtn.S,../arch/amd64/crtn.S,../arch/i386/crtn.S
 
+[gdt.c]
+depends=../loader/gdt.c
+
+[idt.c]
+depends=../loader/idt.c
+
 [multiboot.c]
 depends=../loader/multiboot.c,../drivers/boot/multiboot.h
 

src/loader/multiboot.c

@@ -13,6 +13,7 @@
 # include <kernel/drivers/display.h>
 # include "arch/amd64/gdt.h"
 # include "arch/i386/gdt.h"
+# include "arch/i386/idt.h"
 # include "drivers/boot/multiboot.h"
 
 # ifndef LOADER_CLOCK
@@ -93,6 +94,13 @@ int multiboot(const ukMultibootInfo * mi)
 		return 4;
 	}
 
+	/* setup the IDT */
+	if(idt_init() == NULL)
+	{
+		puts("Could not setup the IDT");
+		return 5;
+	}
+
 	/* load the kernel */
 	if(!(mi->flags & BOOT_MULTIBOOT_INFO_HAS_MODS))
 	{

src/loader/project.conf

@@ -36,7 +36,7 @@ ldflags=`../../tools/platform.sh -V LIBULOADER_LDFLAGS -C "$$ARCH"`
 [uLoader.bin]
 type=binary
 depends=$(OBJDIR)crtbegin.o,$(OBJDIR)crtend.o,$(OBJDIR)crti.o,$(OBJDIR)crtn.o,$(OBJDIR)libuLoader.a,../arch/amd64/uKernel.ld,../arch/i386/uKernel.ld
-sources=arch.S,gdt.c,main.c,multiboot.c,start.S
+sources=arch.S,gdt.c,idt.c,main.c,multiboot.c,start.S
 asflags=`../../tools/platform.sh -V ULOADER_CFLAGS -C "$$ARCH"`
 cflags=`../../tools/platform.sh -V ULOADER_CFLAGS -C "$$ARCH"`
 ldflags=$(OBJDIR)crti.o $(OBJDIR)crtbegin.o $(OBJDIR)crtend.o $(OBJDIR)crtn.o $(OBJDIR)libuLoader.a `../../tools/platform.sh -V ULOADER_LDFLAGS -C "$$ARCH"`
@@ -85,7 +85,7 @@ depends=$(OBJDIR)../lib/libk.a
 depends=../drivers/boot/multiboot.h,../../include/kernel/drivers/bus.h,../../include/kernel/drivers/console.h
 
 [start.S]
-depends=../arch/i386/gdt.S,../arch/i386/intr.S,../arch/i386/loader.S,../arch/i386/multiboot.S
+depends=../arch/i386/gdt.S,../arch/i386/idt.S,../arch/i386/intr.S,../arch/i386/loader.S,../arch/i386/multiboot.S
 
 [syscalls.S]
 depends=$(OBJDIR)../lib/libc/src/syscalls.o

src/loader/start.S

@@ -7,6 +7,7 @@
 /* check for supported architectures */
 #if defined(__i386__)
 # include "../arch/i386/gdt.S"
+# include "../arch/i386/idt.S"
 # include "../arch/i386/intr.S"
 # include "../arch/i386/loader.S"
 #else