protected-mode

I'm developing a boot loader, which will boot into a simple kernel after switching into protected mode. I used this paper as a tutorial, somewhere in chapter four or five. In theory it is supposed to start in 16-bit real mode, load the kernel into memory, switch to 32-bit protected mode and start executing the kernel code. However, when I switch into protected mode and far jump or jump to another segment, it triple faults. Here is the main boot sector code: [org 0x7c00] KERNEL_OFFSET equ 0x1000 mov [BOOT_DRIVE], dl ;Get the current boot drive from the BIOS mov bp, 0x9000 ;Set up stack, with

I would like to ask if it is GRUB that switch the CPU to protected mode during boot up or is it the Linux kernel that does it. And also I would like to ask - is the kernel itself (vmlinuz) an ELF or is it plain binary format? Thanks. GRUB does drop you in protected mode. The GRUB Multiboot Specification (version 0.6.96) Section 3.2 tells you this ‘CR0’ Bit 31 (PG) must be cleared. Bit 0 (PE) must be set. Other bits are all undefined. And CR0 Register mapping tells you that the system should be in protected mode. Linux is not a multiboot kernel and does not rely on some bootloader for switching

If I run IE in protected mode, its integrity level is low. And if I then create a medium integrity level process (impl by ActiveX), IE will warn the user with an Elevation Warning window. How do I create a medium process from another processes (like chrome) with a low integrity level? You will have to do what Internet Explorer (and Chrome) do. The browser tabs themselves are separate processes running at Low Mandatory Integrity Level . But there is still a Medium level parent process. The client processes communicate back to the "parent" process though named pipes, asking the parent to perform

Many of our users are reporting that they are getting a blank page when using IE11 to access our website. Sometimes they don't even get a blank page, the browser just stays on the last page visited. These users can access other domains (such as google.com) without a problem. For the browsers that are failing, if those users disable Protected Mode in IE, then they can again access our site, but this isn't a good solution because we have thousands of users and we can't go telling each of them to reconfigure their browsers, not to mention that we're completely losing the business of those

I am currently playing around with x86 Assember in order to sharpen my low-level programming skills. Currently, I am facing a little problem with the addressing scheme in 32-Bit Protected Mode. The situation is the following: I have a Program loaded at 0x7e0 which switches the CPU to Protected Mode and jumps to the according label in the code: [...] code to switch CPU in Protected Mode [...] jmp ProtectedMode [...] bits 32 ProtectedMode: .halt: hlt jmp .halt This works absolutely fine so far. The "jmp ProtectedMode" works without a explicit far jump to clear the prefetch queue - since this

I am building an 32 bit OS in assembly. I have setup the IDT and I am handling program interruptus through int instruction. How can I enable the syscall and sysenter instructions and how do I handle them/return? Is true that syscall instruction isn't supported in 32 bit by Intel processors so I can't use it? Is true that sysret instruction isn't safe? Do somewhere exist a tutorial for that? EDIT : My main question is how to enable the syscall and sysenter instructions! (No duplication) See the OSdev wiki for details on sysenter , including a note about how to avoid a security/safety problem.