CPU_XOR_S - Linux

Overview

CPU_XOR_S is a Linux command used to perform a bitwise XOR (exclusive OR) operation on the CPU model-specific registers (MSRs). It allows precise and advanced manipulation of CPU settings, primarily used in overclocking scenarios or debugging at the lowest system level.

Syntax

CPU_XOR_S opt reg val

Where:

• opt is the operation to be performed, either "xor" (default) or "xor_clear".
• reg is the MSR address in hexadecimal format (e.g., 0x1A0).
• val is the bitmask value to XOR with the MSR.

Options/Flags

| Option | Description | Default Value |
|—|—|—|
| "xor" | Perform a bitwise XOR operation on the MSR. | N/A |
| "xor_clear" | Perform a bitwise XOR operation and then clear the changed bits back to 0. | N/A |

Examples

XOR a specific bit in MSR 0x1A0 to enable overclocking:

CPU_XOR_S xor 0x1A0 0x00000001

XOR and clear bits in MSR 0x1A0 to disable power saving:

CPU_XOR_S xor_clear 0x1A0 0x0000000F

Common Issues

• Incorrect MSR address: Ensure you use the correct MSR address for your intended operation. Check your CPU documentation or reference reliable sources to obtain the correct MSR addresses.
• Insufficient permissions: CPU_XOR_S requires root privileges to run successfully. Ensure you are running the command as the root user or using sudo to gain necessary permissions.

Integration

CPU_XOR_S can be integrated with other commands for advanced tasks:

• bash: Use CPU_XOR_S in scripts to automate MSR manipulations.
• i2cset: Combine with i2cset to modify registers on connected I2C devices, such as temperature sensors.

Related Commands

• rdmsr, wrmsr: Low-level MSR read and write utilities.
• cpuid: Displays CPU information, including MSR addresses.