Limited direct execution - Revision history

Rice: /* Limiting operations */

2024-10-04T18:08:37Z

Limiting operations

← Older revision		Revision as of 18:08, 4 October 2024
Line 15:		Line 15:
	To limit sensitive operations, most operating systems have two modes: '''kernel mode''' and '''user mode'''. In kernel mode, all instructions are fair game. In user mode, certain sensitive operations such as I/O and process/resource management would raise an exception.		To limit sensitive operations, most operating systems have two modes: '''kernel mode''' and '''user mode'''. In kernel mode, all instructions are fair game. In user mode, certain sensitive operations such as I/O and process/resource management would raise an exception.

	We want to limit a process' control but still allow them to perform necessary functions. This is done through '''system calls'''.		We want to limit a process' control but still allow them to perform necessary functions. This is done through '''system calls'''. When a user program wants to access restricted resources, they make a system call, which then use the '''trap''' instruction to elevate to kernel mode. The kernel then checks the necessary permissions.
	[[Category:Operating System]]		[[Category:Operating System]]

Rice at 18:01, 2 October 2024

2024-10-02T18:01:08Z

@@ Line 4: / Line 4: @@
 [[File:OSTEP 6.1.png|thumb|OSTEP: Direct Execution Protocol (Without Limits)]]
 Let's first talk about the simpler sibling of limited direct execution. '''Direct execution''' (without limits) simply allows programs to run on the CPU.
 [[Category:Operating System]]

Rice at 17:49, 2 October 2024

2024-10-02T17:49:00Z

← Older revision		Revision as of 17:49, 2 October 2024
Line 1:		Line 1:
	'''Limited direct execution''' is a technique of allowing programs to partially execute on the CPU directly. This ensures the two necessities of CPU [[virtualization]]: performance and control.		'''Limited direct execution''' is a technique of allowing programs to partially execute on the CPU directly. This ensures the two necessities of CPU [[virtualization]]: performance and control.

			== Direct execution ==
			[[File:OSTEP 6.1.png\|thumb\|OSTEP: Direct Execution Protocol (Without Limits)]]
			Let's first talk about the simpler sibling of limited direct execution. '''Direct execution''' (without limits) simply allows programs to run on the CPU.
	[[Category:Operating System]]		[[Category:Operating System]]

Rice: Created page with "'''Limited direct execution''' is a technique of allowing programs to partially execute on the CPU directly. This ensures the two necessities of CPU virtualization: performance and control. Category:Operating System"

2024-10-02T17:46:09Z

Created page with "'''Limited direct execution''' is a technique of allowing programs to partially execute on the CPU directly. This ensures the two necessities of CPU virtualization: performance and control. Category:Operating System"

New page

'''Limited direct execution''' is a technique of allowing programs to partially execute on the CPU directly. This ensures the two necessities of CPU [[virtualization]]: performance and control.
[[Category:Operating System]]