rdmsr.cpp File Reference

rdmsr command More...

#include "pch.h"

Typedefs
typedef BOOL(WINAPI *	glpie_t) (LOGICAL_PROCESSOR_RELATIONSHIP, PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX, PDWORD)
	defines the GetLogicalProcessorInformationEx function

Functions
VOID	CommandRdmsrHelp ()
	help of the rdmsr command
VOID	CommandRdmsr (vector< CommandToken > CommandTokens, string Command)
	rdmsr command handler

Variables
BOOLEAN	g_IsKdModuleLoaded
	shows whether the kernel debugger (KD) module is loaded or not

Detailed Description

rdmsr command

Author

Sina Karvandi (sina@.nosp@m.hype.nosp@m.rdbg..nosp@m.org)

Version

0.1

Date

2020-05-27

Copyright

This project is released under the GNU Public License v3.

Typedef Documentation

glpie_t

typedef BOOL(WINAPI * glpie_t) (LOGICAL_PROCESSOR_RELATIONSHIP, PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX, PDWORD)

defines the GetLogicalProcessorInformationEx function

Function Documentation

CommandRdmsr()

VOID CommandRdmsr	(	vector< CommandToken >	CommandTokens,
		string	Command )

rdmsr command handler

Parameters

CommandTokens
Command

Returns

VOID

{
    BOOL                           Status;
    SIZE_T                         NumCPU;
    DEBUGGER_READ_AND_WRITE_ON_MSR MsrReadRequest;
    ULONG                          ReturnedLength;
    UINT64                         Msr;
    BOOL                           IsNextCoreId   = FALSE;
    BOOL                           SetMsr         = FALSE;
    UINT32                         CoreNumer      = DEBUGGER_READ_AND_WRITE_ON_MSR_APPLY_ALL_CORES;
    BOOLEAN                        IsFirstCommand = TRUE;
 
    if (CommandTokens.size() >= 5)
    {
        ShowMessages("incorrect use of the '%s'\n\n",
                     GetCaseSensitiveStringFromCommandToken(CommandTokens.at(0)).c_str());
        CommandRdmsrHelp();
        return;
    }
 
    for (auto Section : CommandTokens)
    {
        if (IsFirstCommand == TRUE)
        {
            IsFirstCommand = FALSE;
            continue;
        }
 
        if (IsNextCoreId)
        {
            if (!ConvertTokenToUInt32(Section, &CoreNumer))
            {
                ShowMessages("please specify a correct hex value for core id\n\n");
                CommandRdmsrHelp();
                return;
            }
            IsNextCoreId = FALSE;
            continue;
        }
 
        if (CompareLowerCaseStrings(Section, "core"))
        {
            IsNextCoreId = TRUE;
            continue;
        }
 
        if (SetMsr || !ConvertTokenToUInt64(Section, &Msr))
        {
            ShowMessages("please specify a correct hex value to be read\n\n");
            CommandRdmsrHelp();
            return;
        }
        SetMsr = TRUE;
    }
 
    //
    // Check if msr is set or not
    //
    if (!SetMsr)
    {
        ShowMessages("please specify a correct hex value to be read\n\n");
        CommandRdmsrHelp();
        return;
    }
    if (IsNextCoreId)
    {
        ShowMessages("please specify a correct hex value for core\n\n");
        CommandRdmsrHelp();
        return;
    }
 
    AssertShowMessageReturnStmt(g_IsKdModuleLoaded, g_DeviceHandle, ASSERT_MESSAGE_KD_NOT_LOADED, ASSERT_MESSAGE_DRIVER_NOT_LOADED, AssertReturn);
 
    MsrReadRequest.ActionType = DEBUGGER_MSR_READ;
    MsrReadRequest.Msr        = Msr;
    MsrReadRequest.CoreNumber = CoreNumer;
 
    //
    // Find logical cores count
    //
    SIZE_T NumCores = GetWindowsNumaNumberOfCores();
    NumCPU          = NumCores > 0 ? NumCores : GetWindowsCompatibleNumberOfCores();
 
    //
    // allocate buffer for transferring messages
    //
    UINT64 * OutputBuffer = (UINT64 *)malloc(sizeof(UINT64) * NumCPU);
 
    ZeroMemory(OutputBuffer, sizeof(UINT64) * NumCPU);
 
    Status = DeviceIoControl(
        g_DeviceHandle,                        // Handle to device
        IOCTL_DEBUGGER_READ_OR_WRITE_MSR,      // IO Control Code (IOCTL)
        &MsrReadRequest,                       // Input Buffer to driver.
        SIZEOF_DEBUGGER_READ_AND_WRITE_ON_MSR, // Input buffer length
        OutputBuffer,                          // Output Buffer from driver.
        (DWORD)(sizeof(UINT64) * NumCPU),      // Length of output buffer in bytes.
        &ReturnedLength,                       // Bytes placed in buffer.
        NULL                                   // synchronous call
    );
 
    if (!Status)
    {
        ShowMessages("ioctl failed with code (%x), either msr index or core id is invalid\n",
                     GetLastError());
        free(OutputBuffer);
        return;
    }
 
    //
    // btw, %x is enough, no need to %llx
    //
    if (CoreNumer == DEBUGGER_READ_AND_WRITE_ON_MSR_APPLY_ALL_CORES)
    {
        //
        // Show all cores
        //
        for (SIZE_T i = 0; i < NumCPU; i++)
        {
            ShowMessages("core : 0x%x - msr[%llx] = %s\n", i, Msr, SeparateTo64BitValue((OutputBuffer[i])).c_str());
        }
    }
    else
    {
        //
        // Show for a single-core
        //
        ShowMessages("core : 0x%x - msr[%llx] = %s\n", CoreNumer, Msr, SeparateTo64BitValue((OutputBuffer[0])).c_str());
    }
 
    //
    // Free the buffer
    //
    free(OutputBuffer);
}

CommandRdmsrHelp()

VOID CommandRdmsrHelp

(

)

help of the rdmsr command

Returns

VOID

{
    ShowMessages("rdmsr : reads a model-specific register (MSR).\n\n");
 
    ShowMessages("syntax : \trdmsr [Msr (hex)] [core CoreNumber (hex)]\n");
 
    ShowMessages("\n");
    ShowMessages("\t\te.g : rdmsr c0000082\n");
    ShowMessages("\t\te.g : rdmsr c0000082 core 2\n");
}

Variable Documentation

g_IsKdModuleLoaded

BOOLEAN g_IsKdModuleLoaded

extern

shows whether the kernel debugger (KD) module is loaded or not