Re: [PATCH v4 2/8] UefiCpuPkg/CpuDxe: Remove unnecessary macros

["Dong, Eric" <eric.dong@intel.com>]

Reviewed-by: Eric Dong <eric.dong@intel.com>

> -----Original Message-----
> From: Ni, Ray
> Sent: Thursday, August 1, 2019 5:58 PM
> To: devel@edk2.groups.io
> Cc: Yao, Jiewen <jiewen.yao@intel.com>; Dong, Eric <eric.dong@intel.com>;
> Laszlo Ersek <lersek@redhat.com>
> Subject: [PATCH v4 2/8] UefiCpuPkg/CpuDxe: Remove unnecessary macros
> 
> Today's code defines macros like CR0_PG, CR0_WP, CR4_PSE, CR4_PAE when
> checking whether individual bits are set in CR0 or CR4 register.
> 
> The patch changes the code to use IA32_CR0 and IA32_CR4 structure defined
> in MdePkg/Include/Library/BaseLib.h so that the module local macros can be
> removed.
> 
> There is no functionality impact to this change.
> 
> Signed-off-by: Ray Ni <ray.ni@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> ---
>  UefiCpuPkg/CpuDxe/CpuPageTable.c | 43 ++++++++++++++++++------------
> --
>  1 file changed, 24 insertions(+), 19 deletions(-)
> 
> diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c
> b/UefiCpuPkg/CpuDxe/CpuPageTable.c
> index c369b44f12..16a2528b55 100644
> --- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
> +++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
> @@ -1,7 +1,7 @@
>  /** @file
>    Page table management support.
> 
> -  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2017 - 2019, Intel Corporation. All rights
> + reserved.<BR>
>    Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
> 
>    SPDX-License-Identifier: BSD-2-Clause-Patent @@ -21,14 +21,6 @@
> #include "CpuDxe.h"
>  #include "CpuPageTable.h"
> 
> -///
> -/// Paging registers
> -///
> -#define CR0_WP                      BIT16
> -#define CR0_PG                      BIT31
> -#define CR4_PSE                     BIT4
> -#define CR4_PAE                     BIT5
> -
>  ///
>  /// Page Table Entry
>  ///
> @@ -161,6 +153,8 @@ GetCurrentPagingContext (
>    UINT32                          RegEax;
>    CPUID_EXTENDED_CPU_SIG_EDX      RegEdx;
>    MSR_IA32_EFER_REGISTER          MsrEfer;
> +  IA32_CR4                        Cr4;
> +  IA32_CR0                        Cr0;
> 
>    //
>    // Don't retrieve current paging context from processor if in SMM mode.
> @@ -172,21 +166,24 @@ GetCurrentPagingContext (
>      } else {
>        mPagingContext.MachineType = IMAGE_FILE_MACHINE_I386;
>      }
> -    if ((AsmReadCr0 () & CR0_PG) != 0) {
> +
> +    Cr0.UintN = AsmReadCr0 ();
> +    Cr4.UintN = AsmReadCr4 ();
> +
> +    if (Cr0.Bits.PG != 0) {
>        mPagingContext.ContextData.X64.PageTableBase = (AsmReadCr3 () &
> PAGING_4K_ADDRESS_MASK_64);
>      } else {
>        mPagingContext.ContextData.X64.PageTableBase = 0;
>      }
> -
> -    if ((AsmReadCr4 () & CR4_PSE) != 0) {
> +    if (Cr0.Bits.WP  != 0) {
> +      mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_WP_ENABLE;
> +    }
> +    if (Cr4.Bits.PSE != 0) {
>        mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PSE;
>      }
> -    if ((AsmReadCr4 () & CR4_PAE) != 0) {
> +    if (Cr4.Bits.PAE != 0) {
>        mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE;
>      }
> -    if ((AsmReadCr0 () & CR0_WP) != 0) {
> -      mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_WP_ENABLE;
> -    }
> 
>      AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
>      if (RegEax >= CPUID_EXTENDED_CPU_SIG) { @@ -581,12 +578,14 @@
> IsReadOnlyPageWriteProtected (
>    VOID
>    )
>  {
> +  IA32_CR0  Cr0;
>    //
>    // To avoid unforseen consequences, don't touch paging settings in SMM
> mode
>    // in this driver.
>    //
>    if (!IsInSmm ()) {
> -    return ((AsmReadCr0 () & CR0_WP) != 0);
> +    Cr0.UintN = AsmReadCr0 ();
> +    return (BOOLEAN) (Cr0.Bits.WP != 0);
>    }
>    return FALSE;
>  }
> @@ -599,12 +598,15 @@ DisableReadOnlyPageWriteProtect (
>    VOID
>    )
>  {
> +  IA32_CR0  Cr0;
>    //
>    // To avoid unforseen consequences, don't touch paging settings in SMM
> mode
>    // in this driver.
>    //
>    if (!IsInSmm ()) {
> -    AsmWriteCr0 (AsmReadCr0 () & ~CR0_WP);
> +    Cr0.UintN = AsmReadCr0 ();
> +    Cr0.Bits.WP = 0;
> +    AsmWriteCr0 (Cr0.UintN);
>    }
>  }
> 
> @@ -616,12 +618,15 @@ EnableReadOnlyPageWriteProtect (
>    VOID
>    )
>  {
> +  IA32_CR0  Cr0;
>    //
>    // To avoid unforseen consequences, don't touch paging settings in SMM
> mode
>    // in this driver.
>    //
>    if (!IsInSmm ()) {
> -    AsmWriteCr0 (AsmReadCr0 () | CR0_WP);
> +    Cr0.UintN = AsmReadCr0 ();
> +    Cr0.Bits.WP = 1;
> +    AsmWriteCr0 (Cr0.UintN);
>    }
>  }
> 
> --
> 2.21.0.windows.1