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[BITS 64]
jmp 0x08:next ;<-- NASM complains
next:
hltCode: Select all
push 0x8
lea rax, [next]
push rax
retfCode: Select all
00009322702e[CPU0 ] LGDT64_Ms: loaded base64 address is not in canonical form!
00009322702e[CPU0 ] interrupt(long mode): IDT entry extended attributes DWORD4 TYPE != 0Code: Select all
gdtInit:
lgdt [gdtP]
mov ax, 0x10
mov ds, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ss, ax
push 0x8
lea rax, [gdtInitNext]
push rax
retf ;<-- Fails here
gdtInitNext:
retCode: Select all
gdt[0] = (u64bit)0x0;
gdt[1] = (u64bit)0x390400;
gdt[2] = (u64bit)0x10000;
gdt[3] = (u64bit)0x3F0400;yasm implemnts 64-bit instructions and addresses difrently from NASMjnc100 wrote:I've just tried that technique (albeit assembled under yasm but it should produce the same code) in my bootloader and it seemed to work fine. Are you definitely in 64-bit long mode (not compatibility), cs.l = 1, cs.d = 0 and assembling in a section with the BITS 64 directive?
Regards,
John.
edit: I note you've just edited your post to change the error message that's produced. The new one seems to imply the error is with the lgdt instruction? If not, suggest you use bochs debugger and examine the value of rax after the lea instruction.
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build
|
|- Makefile
|- kernel
|- load.o <-- is put in build directory when it should be in asm
kernel
|
|- asm
|- load.s
|- (load.o) <-- load.o should be here
|- kMain.c
|- kMain.oCode: Select all
SOURCES=../kernel/asm/load.o ../kernel/kMain.o
CFLAGS=-I ../kernel/include -m64 -nostdlib -nostdinc -nodefaultlibs -fno-builtin -fno-stack-protector
LDFLAGS=-melf_x86_64 -Tlink.ld
ASFLAGS=-felf64
all: $(SOURCES) link
clean:
rm *.o ../kernel/asm/*.o ../kernel/*.o kernel
link:
ld $(LDFLAGS) -o kernel $(SOURCES)
.s.o:
yasm $(ASFLAGS) $<Please provide a bit more information. In what sense?HJED wrote:yasm implemnts 64-bit instructions and addresses difrently from NASM
Er, no. I don't think so. How did you manage to generate those values? I suggest you break it down field by field and decide exactly what you want to put in each field.sngskunk wrote:Here is my GDT:
Is this correct?Code: Select all
gdt[0] = (u64bit)0x0; gdt[1] = (u64bit)0x390400; gdt[2] = (u64bit)0x10000; gdt[3] = (u64bit)0x3F0400;
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00009340690e[CPU0 ] return_protected: CS selector null
00009340690e[CPU0 ] interrupt(long mode): IDT entry extended attributes DWORD4 TYPE != 0Code: Select all
[BITS 64]
%include "../kernel/include/asm/common.s"
[GLOBAL gdtInit]
[EXTERN gdtP]
gdtInit:
lgdt [gdtP]
push 0x08
lea rax, [gdtInitFinish]
push rax
retf ;<--- Code stops here and returns error above
gdtInitFinish:
retCode: Select all
/*
* Global Descriptor Structure
*/
typedef struct {
u16bit limit;
u16bit baseLow;
u08bit baseMid;
u08bit type;
u08bit flags;
u08bit baseHigh;
} __attribute__((packed)) gdtEntry;
/*
* Global Descriptor Pointer
*/
typedef struct {
u16bit limit;
u64bit base;
} __attribute__((packed)) gdtPointer;
/* Setup Table and Pointer */
gdtEntry gdt[4];
gdtPointer gdtP;
void gdtStart(void) {
/* Create GDT entries */
gdtSet(0, 0, 0);
gdtSet(1, 0x9C, 0x20);
gdtSet(2, 0x90, 0);
gdtSet(3, 0xFC, 0x20);
/* Create GDT Pointer */
gdtP.limit = (sizeof(gdtEntry) * 4) - 1;
gdtP.base = (u64bit)&gdt;
gdtInit();
}
void gdtSet(u08bit number, u08bit type, u08bit flags) {
/* Set Base and Limit Address */
gdt[number].baseLow = 0;
gdt[number].baseMid = 0;
gdt[number].baseHigh = 0;
gdt[number].limit = 0;
/* Set Type and Flags */
gdt[number].type = type;
gdt[number].flags = flags;
}is because 64 bit modes require all pointers to be in canonical form. This means that the MSB's of the pointer must all be the same as the last valid MSB (this means bit 47 for the first long mode implementation).00009322702e[CPU0 ] LGDT64_Ms: loaded base64 address is not in canonical form!
00009322702e[CPU0 ] interrupt(long mode): IDT entry extended attributes DWORD4 TYPE != 0