Couple Of Questions
Posted: Sat Jan 31, 2009 8:47 am
For quite some time, I've been working on a problem of mine which raised some questions. Not so long ago I was having a very strange problem; as soon as I added a certain line of code (it was a push_back call for a vector), the kernel page-faulted. You could say "Check your push_back or dynamic memory allocation code", but the strange thing is, the code wasn't even being called! Just putting the line there page-faulted the kernel. So I wondered "What could cause this?" and at the moment the only thing I could come up with is something being loaded incorrectly or something wrong with the linker. So my first question is, would someone take a look at my linker script and see if there's anything horribly wrong with it?
Secondly, as I was browsing around about linker scripts, I noticed our wiki says something about the (*.rodata*) section for the ELF format and (*.rdata*) for the PE/COFF format. I'm wondering if I'm supposed to use this (I'm using ELF with a GCC Cross-Compiler):
or this:
In tutorials and other OS' I usually see the first, but our wiki for some reason suggests the second. Finally, I would like to know where to put this section. Again, the wiki says in the text section, but I've noticed some people also put it in the data section of the script.
Thanks for your time,
Creature
EDIT: Just recently I found something new; I was testing my vector implementation with a custom class foo I quickly made to test some functions. I got a page-fault, then I started using the 'Print-Something-In-The-Bochs-Console' way to find out exactly where it page-faulted, and when I put this in front of the function:
The page-fault disappeared. I have no idea what is going on here and am amazed to see this fixed a page-fault, but the function doesn't do anything, and even if it did, it just writes to 2 or 3 ports that Bochs reads to print something in the background console!
Code: Select all
ENTRY(BootEntry)
OUTPUT_FORMAT("elf32-i386")
SECTIONS
{
.text 0x100000 :
{
code = .;
*(.text)
*(.rodata) /* Assuming ELF cross-compiler. */
. = ALIGN(4096);
}
.data :
{
/* Constructor and destructor variables are only used in ASM, so C-linkage is not necessary. */
ConstrStart = .;
*(.ctor*)
ConstrEnd = .;
DestrStart = .;
*(.dtor*)
DestrEnd = .;
data = .;
*(.data)
*(.rodata) /* Assuming ELF cross-compiler, does this even need to be put here? */
. = ALIGN(4096);
}
.bss :
{
bss = .;
*(.bss)
. = ALIGN(4096);
}
end = .;
}
INPUT
(
Entry.obj
AsmImp.obj
DescriptorTables.obj
ISR.obj
IRQ.obj
GRUB.o
Kernel.o
Keyboard.o
Event.o
CppInit.o
cstring.o
CCRead.o
CCWrite.o
Heap.o
Memory.o
Multitasking.o
OrderedList.o
Paging.o
Floppy.o
NuclixFont.o
FireDit.o
CmdHandlers.o
FireShell.o
Main.o
)
OUTPUT(Kernel.nsf)
Code: Select all
(*.rodata)
Code: Select all
(*.rodata*)
Thanks for your time,
Creature
EDIT: Just recently I found something new; I was testing my vector implementation with a custom class foo I quickly made to test some functions. I got a page-fault, then I started using the 'Print-Something-In-The-Bochs-Console' way to find out exactly where it page-faulted, and when I put this in front of the function:
Code: Select all
BX_DebugStr(""); //Will output nothing as DebugStr will stop if the null-terminator is found.
The page-fault disappeared. I have no idea what is going on here and am amazed to see this fixed a page-fault, but the function doesn't do anything, and even if it did, it just writes to 2 or 3 ports that Bochs reads to print something in the background console!
.