I am presently working with Model Specific Registers and have been studying the kernel module implementation found in arch/x86/kernel/msr.c. I am attempting to understand what the implementation of the msr_ioctl(X86_IOC_RDMSR_REGS) call is doing.

msr_ioctl(X86_IOC_RDMSR_REGS) calls rdmsr_safe_regs_on_cpu() (arch/x86/lib/msr-smp.c, line 180) which sets up __rdmsr_safe_regs_on_cpu() (arch/x86/lib/msr-smp.c, line 166) as a callback function to perform the actual work. This callback function then calls rdmsr_safe_regs().

I am unable to find the implementation for rdmsr_safe_regs(). lxr only mentions references and a prototype definition.

I've also manually grepped through the entire kernel source tree and have not been able to find where rdmsr_safe_regs is defined.

I have poked around online, but have so far not been able to generate the correct query to find an answer.