On 09/11/19 03:45, Eric Dong wrote:
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1039
>
> Current implementation not checks system mode before using
> PAGE_TABLE_LIB_PAGING_CONTEXT.ContextData.X64 or
> PAGE_TABLE_LIB_PAGING_CONTEXT.ContextData.Ia32. This patch check
> the mode before using the correct one.
>
> Cc: Ray Ni <ray...@intel.com>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Signed-off-by: Eric Dong <eric.d...@intel.com>
> ---
> UefiCpuPkg/CpuDxe/CpuPageTable.c | 52 +++++++++++++++++++++++---------
> 1 file changed, 37 insertions(+), 15 deletions(-)
>
> diff --git a/UefiCpuPkg/CpuDxe/CpuPageTable.c
> b/UefiCpuPkg/CpuDxe/CpuPageTable.c
> index ec5cd424fc..308f93b1cd 100644
> --- a/UefiCpuPkg/CpuDxe/CpuPageTable.c
> +++ b/UefiCpuPkg/CpuDxe/CpuPageTable.c
> @@ -155,6 +155,8 @@ GetCurrentPagingContext (
> MSR_IA32_EFER_REGISTER MsrEfer;
> IA32_CR4 Cr4;
> IA32_CR0 Cr0;
> + UINT32 *Attributes;
> + UINTN *PageTableBase;
>
> //
> // Don't retrieve current paging context from processor if in SMM mode.
> @@ -163,29 +165,33 @@ GetCurrentPagingContext (
> ZeroMem (&mPagingContext, sizeof(mPagingContext));
> if (sizeof(UINTN) == sizeof(UINT64)) {
> mPagingContext.MachineType = IMAGE_FILE_MACHINE_X64;
> + Attributes = &mPagingContext.ContextData.X64.Attributes;
> + PageTableBase = &mPagingContext.ContextData.X64.PageTableBase;
> } else {
> mPagingContext.MachineType = IMAGE_FILE_MACHINE_I386;
> + Attributes = &mPagingContext.ContextData.Ia32.Attributes;
> + PageTableBase = (UINTN
> *)&mPagingContext.ContextData.Ia32.PageTableBase;
(1) This is quite unfortunate. I don't like the cast.
I understand why it is used here -- when we build for X64, then UINTN is
UINT64, and so PageTableBase points to a UINT64. But
"mPagingContext.ContextData.Ia32.PageTableBase" is a UINT32, so the
compiler will complain about the incompatible pointer assignment.
Therefore you use an explicit cast -- which would be wrong, if the code
ever ran, but then again, that code will never run.
I don't like this trick.
Furthermore, the same issue will exist on the *other* branch, if you
build the present code for IA32 -- you didn't use a cast there. When
building for IA32, PageTableBase points to a UINT32. But, on the first
branch, "mPagingContext.ContextData.X64.PageTableBase" is a UINT64.
Therefore, the compiler will warn the same (although the code will never
run).
Did you build the patch for IA32?
I think there are two ways to fix this.
(1a) The ugly (but correct) fix is to use "#ifdef MDE_CPU_IA32" and
"#ifdef MDE_CPU_X64" directives, and *no* casts. In other words, we
should never compile the code that we won't run.
(1b) The nice (and also correct) fix is to introduce a helper function:
VOID
GetPagingDetails (
IN PAGE_TABLE_LIB_PAGING_CONTEXT_DATA *PagingContextData,
OUT UINTN **PageTableBase OPTIONAL,
OUT UINT32 **Attributes OPTIONAL
);
There would be two implementations:
- IA32 subdirectory:
if (PageTableBase != NULL) {
*PageTableBase = &PagingContextData->Ia32.PageTableBase;
}
if (Attributes != NULL) {
*Attributes = &PagingContextData->Ia32.Attributes;
}
- X64 subdirectory:
if (PageTableBase != NULL) {
*PageTableBase = &PagingContextData->X64.PageTableBase;
}
if (Attributes != NULL) {
*Attributes = &PagingContextData->X64.Attributes;
}
And here we'd do
GetPagingDetails (
&mPagingContext.ContextData,
&PageTableBase,
&Attributes
);
and the rest of the GetCurrentPagingContext() updates would be the same.
> }
>
> Cr0.UintN = AsmReadCr0 ();
> Cr4.UintN = AsmReadCr4 ();
>
> if (Cr0.Bits.PG != 0) {
> - mPagingContext.ContextData.X64.PageTableBase = (AsmReadCr3 () &
> PAGING_4K_ADDRESS_MASK_64);
> + *PageTableBase = (AsmReadCr3 () & PAGING_4K_ADDRESS_MASK_64);
> } else {
> - mPagingContext.ContextData.X64.PageTableBase = 0;
> + *PageTableBase = 0;
> }
> if (Cr0.Bits.WP != 0) {
> - mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_WP_ENABLE;
> + *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;
> + *Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PSE;
> }
> if (Cr4.Bits.PAE != 0) {
> - mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE;
> + *Attributes |= PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE;
> }
> if (Cr4.Bits.LA57 != 0) {
> - mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_5_LEVEL;
> + *Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_5_LEVEL;
> }
>
> AsmCpuid (CPUID_EXTENDED_FUNCTION, &RegEax, NULL, NULL, NULL);
> @@ -197,12 +203,12 @@ GetCurrentPagingContext (
> MsrEfer.Uint64 = AsmReadMsr64(MSR_CORE_IA32_EFER);
> if (MsrEfer.Bits.NXE != 0) {
> // XD activated
> - mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_XD_ACTIVATED;
> + *Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_XD_ACTIVATED;
> }
> }
>
> if (RegEdx.Bits.Page1GB != 0) {
> - mPagingContext.ContextData.Ia32.Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAGE_1G_SUPPORT;
> + *Attributes |=
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAGE_1G_SUPPORT;
> }
> }
> }
> @@ -395,6 +401,7 @@ ConvertPageEntryAttribute (
> {
> UINT64 CurrentPageEntry;
> UINT64 NewPageEntry;
> + UINT32 *PageAttributes;
>
> CurrentPageEntry = *PageEntry;
> NewPageEntry = CurrentPageEntry;
> @@ -438,7 +445,13 @@ ConvertPageEntryAttribute (
> break;
> }
> }
> - if ((PagingContext->ContextData.Ia32.Attributes &
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_XD_ACTIVATED) != 0) {
> +
> + if (PagingContext->MachineType == IMAGE_FILE_MACHINE_X64) {
> + PageAttributes = &PagingContext->ContextData.X64.Attributes;
> + } else {
> + PageAttributes = &PagingContext->ContextData.Ia32.Attributes;
> + }
(2) So here we'd write
GetPagingDetails (
&PagingContext->ContextData,
NULL,
&PageAttributes
);
> + if ((*PageAttributes &
> PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_XD_ACTIVATED) != 0) {
> if ((Attributes & EFI_MEMORY_XP) != 0) {
> switch (PageAction) {
> case PageActionAssign:
> @@ -1338,15 +1351,24 @@ InitializePageTableLib (
> )
> {
> PAGE_TABLE_LIB_PAGING_CONTEXT CurrentPagingContext;
> + UINT32 *Attributes;
> + UINTN *PageTableBase;
>
> GetCurrentPagingContext (&CurrentPagingContext);
>
> + if (CurrentPagingContext.MachineType == IMAGE_FILE_MACHINE_X64) {
> + Attributes = &CurrentPagingContext.ContextData.X64.Attributes;
> + PageTableBase = &CurrentPagingContext.ContextData.X64.PageTableBase;
> + } else {
> + Attributes = &CurrentPagingContext.ContextData.Ia32.Attributes;
> + PageTableBase = (UINTN
> *)&CurrentPagingContext.ContextData.Ia32.PageTableBase;
> + }
> +
(3) This would become
GetPagingDetails (
&CurrentPagingContext.ContextData,
&PageTableBase,
&Attributes
);
> //
> // Reserve memory of page tables for future uses, if paging is enabled.
> //
> - if (CurrentPagingContext.ContextData.X64.PageTableBase != 0 &&
> - (CurrentPagingContext.ContextData.Ia32.Attributes &
> - PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE) != 0) {
> + if ((*PageTableBase != 0) &&
> + (*Attributes & PAGE_TABLE_LIB_PAGING_CONTEXT_IA32_X64_ATTRIBUTES_PAE)
> != 0) {
> DisableReadOnlyPageWriteProtect ();
> InitializePageTablePool (1);
> EnableReadOnlyPageWriteProtect ();
> @@ -1361,10 +1383,10 @@ InitializePageTableLib (
> ASSERT (mLastPFEntryPointer != NULL);
> }
>
> - DEBUG ((DEBUG_INFO, "CurrentPagingContext:\n",
> CurrentPagingContext.MachineType));
> + DEBUG ((DEBUG_INFO, "CurrentPagingContext:\n"));
> DEBUG ((DEBUG_INFO, " MachineType - 0x%x\n",
> CurrentPagingContext.MachineType));
> - DEBUG ((DEBUG_INFO, " PageTableBase - 0x%x\n",
> CurrentPagingContext.ContextData.X64.PageTableBase));
> - DEBUG ((DEBUG_INFO, " Attributes - 0x%x\n",
> CurrentPagingContext.ContextData.X64.Attributes));
> + DEBUG ((DEBUG_INFO, " PageTableBase - 0x%x\n", *PageTableBase));
(4) UINTN values should be cast to UINT64 explicitly, and printed with
"%Lx":
DEBUG ((
DEBUG_INFO,
" PageTableBase - 0x%Lx\n",
(UINT64)*PageTableBase
));
Thanks
Laszlo
> + DEBUG ((DEBUG_INFO, " Attributes - 0x%x\n", *Attributes));
>
> return ;
> }
>
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#47126): https://edk2.groups.io/g/devel/message/47126
Mute This Topic: https://groups.io/mt/34099078/21656
Group Owner: devel+ow...@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com]
-=-=-=-=-=-=-=-=-=-=-=-
