edk2/MdeModulePkg/Core/Dxe/Misc/DebugImageInfo.c
Oliver Smith-Denny 5bc52de687 MdeModulePkg: DebugImageInfoTable: Fix Array Maintenance
The DebugImageInfoTable contains an array of image info
structures. The current implementation removes an entry by
freeing the info structure and putting NULL in that entry of
the array. It then decrements the table size tracked in the table.
However, the array is invalid at this point, it contains a NULL
entry, which the UEFI spec does not envision and it contains a valid
entry past the end of the array as tracked in the spec defined config
table. If the table is consumed at this point it can lead to an
invalid assessment of the image state, which defeats the purpose of
the table.

When a new info structure is added, it then scans for the first NULL
entry adds a pointer to the new info structure there and increments
the table size to cover the entrythat was formerly past the end of
the array.

The current implementation requires that once an unload happens,
more loads happen than unloads and that the last operation is not
an unload (which won't be true in the shell, e.g.). This is
needlessly complex, as the order of the table doesn't matter
(and in fact this implementation doesn't preserve image loading
order either).

This patch updates the removal function to free the desired
info structure, move the last entry of the array to this freed
spot, mark the last entry as NULL, and decrement the table count.
The entry addition function then just always puts a new entry at
the end of the array, expanding it as necessary. This simplifies
the logic and covers the gaps that were present.

Signed-off-by: Oliver Smith-Denny <osde@microsoft.com>
2025-05-07 11:27:35 +08:00

273 lines
8.6 KiB
C

/** @file
Support functions for managing debug image info table when loading and unloading
images.
Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "DxeMain.h"
EFI_DEBUG_IMAGE_INFO_TABLE_HEADER mDebugInfoTableHeader = {
0, // volatile UINT32 UpdateStatus;
0, // UINT32 TableSize;
NULL // EFI_DEBUG_IMAGE_INFO *EfiDebugImageInfoTable;
};
UINTN mMaxTableEntries = 0;
EFI_SYSTEM_TABLE_POINTER *mDebugTable = NULL;
#define EFI_DEBUG_TABLE_ENTRY_SIZE (sizeof (VOID *))
/**
Creates and initializes the DebugImageInfo Table. Also creates the configuration
table and registers it into the system table.
**/
VOID
CoreInitializeDebugImageInfoTable (
VOID
)
{
EFI_STATUS Status;
UINTN Pages;
EFI_PHYSICAL_ADDRESS Memory;
UINTN AlignedMemory;
UINTN AlignmentMask;
UINTN UnalignedPages;
UINTN RealPages;
//
// Allocate 4M aligned page for the structure and fill in the data.
// Ideally we would update the CRC now as well, but the service may not yet be available.
// See comments in the CoreUpdateDebugTableCrc32() function below for details.
//
Pages = EFI_SIZE_TO_PAGES (sizeof (EFI_SYSTEM_TABLE_POINTER));
AlignmentMask = SIZE_4MB - 1;
RealPages = Pages + EFI_SIZE_TO_PAGES (SIZE_4MB);
//
// Attempt to allocate memory below PcdMaxEfiSystemTablePointerAddress
// If PcdMaxEfiSystemTablePointerAddress is 0, then allocate memory below
// MAX_ADDRESS
//
Memory = PcdGet64 (PcdMaxEfiSystemTablePointerAddress);
if (Memory == 0) {
Memory = MAX_ADDRESS;
}
Status = CoreAllocatePages (
AllocateMaxAddress,
EfiBootServicesData,
RealPages,
&Memory
);
if (EFI_ERROR (Status)) {
if (PcdGet64 (PcdMaxEfiSystemTablePointerAddress) != 0) {
DEBUG ((DEBUG_INFO, "Allocate memory for EFI_SYSTEM_TABLE_POINTER below PcdMaxEfiSystemTablePointerAddress failed. \
Retry to allocate memroy as close to the top of memory as feasible.\n"));
}
//
// If the initial memory allocation fails, then reattempt allocation
// as close to the top of memory as feasible.
//
Status = CoreAllocatePages (
AllocateAnyPages,
EfiBootServicesData,
RealPages,
&Memory
);
ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
return;
}
}
//
// Free overallocated pages
//
AlignedMemory = ((UINTN)Memory + AlignmentMask) & ~AlignmentMask;
UnalignedPages = EFI_SIZE_TO_PAGES (AlignedMemory - (UINTN)Memory);
if (UnalignedPages > 0) {
//
// Free first unaligned page(s).
//
Status = CoreFreePages (Memory, UnalignedPages);
ASSERT_EFI_ERROR (Status);
}
Memory = AlignedMemory + EFI_PAGES_TO_SIZE (Pages);
UnalignedPages = RealPages - Pages - UnalignedPages;
if (UnalignedPages > 0) {
//
// Free last unaligned page(s).
//
Status = CoreFreePages (Memory, UnalignedPages);
ASSERT_EFI_ERROR (Status);
}
//
// Set mDebugTable to the 4MB aligned allocated pages
//
mDebugTable = (EFI_SYSTEM_TABLE_POINTER *)(AlignedMemory);
ASSERT (mDebugTable != NULL);
//
// Initialize EFI_SYSTEM_TABLE_POINTER structure
//
mDebugTable->Signature = EFI_SYSTEM_TABLE_SIGNATURE;
mDebugTable->EfiSystemTableBase = (EFI_PHYSICAL_ADDRESS)(UINTN)gDxeCoreST;
mDebugTable->Crc32 = 0;
//
// Install the EFI_SYSTEM_TABLE_POINTER structure in the EFI System
// Configuration Table
//
Status = CoreInstallConfigurationTable (&gEfiDebugImageInfoTableGuid, &mDebugInfoTableHeader);
ASSERT_EFI_ERROR (Status);
}
/**
Update the CRC32 in the Debug Table.
Since the CRC32 service is made available by the Runtime driver, we have to
wait for the Runtime Driver to be installed before the CRC32 can be computed.
This function is called elsewhere by the core when the runtime architectural
protocol is produced.
**/
VOID
CoreUpdateDebugTableCrc32 (
VOID
)
{
ASSERT (mDebugTable != NULL);
mDebugTable->Crc32 = 0;
gBS->CalculateCrc32 ((VOID *)mDebugTable, sizeof (EFI_SYSTEM_TABLE_POINTER), &mDebugTable->Crc32);
}
/**
Adds a new DebugImageInfo structure to the DebugImageInfo Table. Re-Allocates
the table if it's not large enough to accomidate another entry.
@param ImageInfoType type of debug image information
@param LoadedImage pointer to the loaded image protocol for the image being
loaded
@param ImageHandle image handle for the image being loaded
**/
VOID
CoreNewDebugImageInfoEntry (
IN UINT32 ImageInfoType,
IN EFI_LOADED_IMAGE_PROTOCOL *LoadedImage,
IN EFI_HANDLE ImageHandle
)
{
EFI_DEBUG_IMAGE_INFO *Table;
EFI_DEBUG_IMAGE_INFO *NewTable;
UINTN Index;
UINTN TableSize;
//
// Set the flag indicating that we're in the process of updating the table.
//
mDebugInfoTableHeader.UpdateStatus |= EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
Table = mDebugInfoTableHeader.EfiDebugImageInfoTable;
if (mDebugInfoTableHeader.TableSize >= mMaxTableEntries) {
//
// Table is full, so re-allocate another page for a larger table...
//
TableSize = mMaxTableEntries * EFI_DEBUG_TABLE_ENTRY_SIZE;
NewTable = AllocateZeroPool (TableSize + EFI_PAGE_SIZE);
if (NewTable == NULL) {
mDebugInfoTableHeader.UpdateStatus &= ~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
return;
}
//
// Copy the old table into the new one
//
CopyMem (NewTable, Table, TableSize);
//
// Free the old table
//
CoreFreePool (Table);
//
// Update the table header
//
Table = NewTable;
mDebugInfoTableHeader.EfiDebugImageInfoTable = NewTable;
//
// Enlarge the max table entries and set the first empty entry index to
// be the original max table entries.
//
mMaxTableEntries += EFI_PAGE_SIZE / EFI_DEBUG_TABLE_ENTRY_SIZE;
}
// We always put the next entry at the end of the currently consumed table (i.e. first free entry)
Index = mDebugInfoTableHeader.TableSize;
//
// Allocate data for new entry
//
Table[Index].NormalImage = AllocateZeroPool (sizeof (EFI_DEBUG_IMAGE_INFO_NORMAL));
if (Table[Index].NormalImage != NULL) {
//
// Update the entry
//
Table[Index].NormalImage->ImageInfoType = (UINT32)ImageInfoType;
Table[Index].NormalImage->LoadedImageProtocolInstance = LoadedImage;
Table[Index].NormalImage->ImageHandle = ImageHandle;
//
// Increase the number of EFI_DEBUG_IMAGE_INFO elements and set the mDebugInfoTable in modified status.
//
mDebugInfoTableHeader.TableSize++;
mDebugInfoTableHeader.UpdateStatus |= EFI_DEBUG_IMAGE_INFO_TABLE_MODIFIED;
}
mDebugInfoTableHeader.UpdateStatus &= ~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
}
/**
Removes and frees an entry from the DebugImageInfo Table.
@param ImageHandle image handle for the image being unloaded
**/
VOID
CoreRemoveDebugImageInfoEntry (
EFI_HANDLE ImageHandle
)
{
EFI_DEBUG_IMAGE_INFO *Table;
UINTN Index;
mDebugInfoTableHeader.UpdateStatus |= EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
Table = mDebugInfoTableHeader.EfiDebugImageInfoTable;
for (Index = 0; Index < mMaxTableEntries; Index++) {
if ((Table[Index].NormalImage != NULL) && (Table[Index].NormalImage->ImageHandle == ImageHandle)) {
//
// Found a match. Free up the record, then move the final entry down to this slot; we don't care about the
// order of the array
//
CoreFreePool (Table[Index].NormalImage);
Table[Index].NormalImage = Table[mDebugInfoTableHeader.TableSize - 1].NormalImage;
Table[mDebugInfoTableHeader.TableSize - 1].NormalImage = NULL;
//
// Decrease the number of EFI_DEBUG_IMAGE_INFO elements and set the mDebugInfoTable in modified status.
//
mDebugInfoTableHeader.TableSize--;
mDebugInfoTableHeader.UpdateStatus |= EFI_DEBUG_IMAGE_INFO_TABLE_MODIFIED;
break;
}
}
mDebugInfoTableHeader.UpdateStatus &= ~EFI_DEBUG_IMAGE_INFO_UPDATE_IN_PROGRESS;
}