| Age | Commit message (Collapse) | Author |
|---|
|
vsprintf() function to render formatted strings and then the puts system
call to output them.
Moved the vsprintf() function from the kernel to the library.
Furthermore, the prototype for the function has been moved from the
kernel's headers, to the new header file stdio.h.
Renamed the kernel's internal printf() function to printk() in order to
avoid confusion with the library provided function.
Renamed the sys_print system call to the more appropriate name,
sys_puts.
Added a new system call sys_time, which returns the system's uptime in
seconds. This is mainly for testing the userspace binary and will not be
permanent.
Added the file time.c to the library which contains the caller for
sys_time and a helper routine sleep() which delays execution for the
specified number of seconds. The new header file time.h contains
prototypes for both these functions as well as the definition for the
type time_t.
Fixed a bug in which the value of EAX was not properly passed to the
system call handler, resulting in the wrong system call being executed.
This was caused by the code in the SAVE macro not properly preserving
the value.
Fixed a bug in which the value of EAX was not preserved during a return
from system call, but rather restored with the original EAX value prior
to the call. As a result, system call return codes were not properly
passed. This has been corrected by introducing a new macro RESTORE_SYS
which carries out the same restore operations, but maintains EAX prior
to the return.
|
|
assembly function register_isr making it usable within the C portions of
the source.
Added a new file panic.s with the function panic that will print a panic
message, disable interrupts and halt the system.
Created the skeleton framework for paging in the new file page.s. The
new function paging_init (called in kboot) will setup a simple page
directory with two tables covering all addresses 0-8MB. It will also
mark pages from 0-1MB as 'supervisor-only' to protect the kernel. NOTE:
The function paging_init must be called before initialising the IDT as
it does not disable interrupts!
Modified the page fault handler to print the offending linear address
along with the supplied error code. Following that, the handler will
initiate a kernel panic. This function (along with panic) assumes
console I/O to be operational.
Modified the userspace test code to deliberately intiate a page fault by
accessing an unmapped page.
|
|
invoking the tool recursively.
Disabled GCC's position-independent-code generation in makefiles.
Modified makefile for kernel/usrbin so that it now compiles and links C
code into the userspace test.
Created errno.h and populated it with standard error definitions.
Replaced the va_list based system call handlers with a system call table
defined in the header kernel/sys.h. NOTE: This header is included in
kmain.c and should ONLY be included there! Do NOT include this header in
sys.c.
Rather than fetching the user's stack pointer and using it to initialize
a va_list, parameters are now passed to the call handlers via the
general purpose registers EAX, EBX, ECX and EDX where EAX contains the
requested call number and conveys the return value.
Setup macros in unistd.h to aid to making system calls from userspace.
Implemented two basic system calls; sys_print and sys_dummy. The former
takes a single char* argument and displays it on screen whilst the
latter is used to populate otherwise empty entries of the system call
table. sys_dummy returns the error ENOSYS whenever it is called.
|
|
32-255. A separate routine in the new file traps.s initializes the first
32 entries with addresses pointing to exception handlers within said
file.
Modified the register_isr function to now accept a descriptor privilege
level which it will assign to the modified IDT entry.
Added a task state segment and corresponding entry to the GDT. The TSS
will store the kernel's stack pointer and stack segment when switching
to userspace. NOTE: The stack pointer MUST be saved manually before
switching to userspace!
Added the framework for a system call interface at interrupt vector 0x80
(128).
|
