[edk2-devel] [PATCH v2 2/3] ArmVirtPkg/PrePi: use standard PeCoff routines for self-relocation
Ard Biesheuvel
ard.biesheuvel at arm.com
Thu Jun 11 12:52:27 UTC 2020
Instead of having a GCC specific routine to perform self-relocation
based on ELF metadata, use the PE/COFF metadata and the existing
PeCoff library routines. This reduces the amount of bespoke assembler
code that is a burden to maintain, and is not portable across the set
of toolchains we support.
This does require some special care, as we have no control over how
the C code references global symbols, so we need to emit these
references from the calling assembler code. Otherwise, they may be
emitted as absolute references, in which case they need to be fixed
up themselves, leading to a circular dependency.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at arm.com>
Acked-by: Jiewen Yao <Jiewen.yao at intel.com>
Acked-by: Laszlo Ersek <lersek at redhat.com>
Acked-by: Sami Mujawar <Sami.Mujawar at arm.com>
---
ArmVirtPkg/ArmVirtQemuKernel.dsc | 10 ++--
ArmVirtPkg/ArmVirtXen.dsc | 10 ++--
ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf | 4 +-
ArmVirtPkg/PrePi/PrePi.c | 35 ++++++++++++++
ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S | 49 +++++---------------
ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S | 47 +++++--------------
6 files changed, 68 insertions(+), 87 deletions(-)
diff --git a/ArmVirtPkg/ArmVirtQemuKernel.dsc b/ArmVirtPkg/ArmVirtQemuKernel.dsc
index 2a6fd6bc06be..9449a01d6e40 100644
--- a/ArmVirtPkg/ArmVirtQemuKernel.dsc
+++ b/ArmVirtPkg/ArmVirtQemuKernel.dsc
@@ -83,14 +83,12 @@ [LibraryClasses.common.DXE_DRIVER]
[LibraryClasses.common.UEFI_DRIVER]
UefiScsiLib|MdePkg/Library/UefiScsiLib/UefiScsiLib.inf
-[BuildOptions.common.EDKII.SEC, BuildOptions.common.EDKII.BASE]
+[BuildOptions]
#
- # CLANG38 with LTO support enabled uses the GNU GOLD linker, which insists
- # on emitting GOT based symbol references when running in shared mode, unless
- # we override visibility to 'hidden' in all modules that make up the PrePi
- # build.
+ # We need to avoid jump tables in SEC modules, so that the PE/COFF
+ # self-relocation code itself is guaranteed to be position independent.
#
- GCC:*_CLANG38_*_CC_FLAGS = -include $(WORKSPACE)/ArmVirtPkg/Include/Platform/Hidden.h
+ GCC:*_*_*_CC_FLAGS = -fno-jump-tables
################################################################################
#
diff --git a/ArmVirtPkg/ArmVirtXen.dsc b/ArmVirtPkg/ArmVirtXen.dsc
index 8a489b253684..278f5d3828ce 100644
--- a/ArmVirtPkg/ArmVirtXen.dsc
+++ b/ArmVirtPkg/ArmVirtXen.dsc
@@ -52,14 +52,12 @@ [LibraryClasses]
[LibraryClasses.common.UEFI_DRIVER]
UefiScsiLib|MdePkg/Library/UefiScsiLib/UefiScsiLib.inf
-[BuildOptions.common.EDKII.SEC, BuildOptions.common.EDKII.BASE]
+[BuildOptions]
#
- # CLANG38 with LTO support enabled uses the GNU GOLD linker, which insists
- # on emitting GOT based symbol references when running in shared mode, unless
- # we override visibility to 'hidden' in all modules that make up the PrePi
- # build.
+ # We need to avoid jump tables in SEC modules, so that the PE/COFF
+ # self-relocation code itself is guaranteed to be position independent.
#
- GCC:*_CLANG38_*_CC_FLAGS = -include $(WORKSPACE)/ArmVirtPkg/Include/Platform/Hidden.h
+ GCC:*_*_*_CC_FLAGS = -fno-jump-tables
################################################################################
#
diff --git a/ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf b/ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf
index 9e58e56fce09..7edf5018089d 100755
--- a/ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf
+++ b/ArmVirtPkg/PrePi/ArmVirtPrePiUniCoreRelocatable.inf
@@ -46,6 +46,7 @@ [LibraryClasses]
SerialPortLib
ExtractGuidedSectionLib
LzmaDecompressLib
+ PeCoffLib
PrePiLib
MemoryAllocationLib
HobLib
@@ -95,6 +96,3 @@ [Pcd]
gArmVirtTokenSpaceGuid.PcdDeviceTreeInitialBaseAddress
gArmTokenSpaceGuid.PcdFdBaseAddress
gArmTokenSpaceGuid.PcdFvBaseAddress
-
-[BuildOptions]
- GCC:*_*_*_DLINK_FLAGS = -Wl,-Bsymbolic,-pie,-T,$(MODULE_DIR)/Scripts/PrePi-PIE.lds
diff --git a/ArmVirtPkg/PrePi/PrePi.c b/ArmVirtPkg/PrePi/PrePi.c
index 72e35028c5bb..4f0c3f98bad6 100755
--- a/ArmVirtPkg/PrePi/PrePi.c
+++ b/ArmVirtPkg/PrePi/PrePi.c
@@ -9,6 +9,7 @@
#include <PiPei.h>
#include <Pi/PiBootMode.h>
+#include <Library/PeCoffLib.h>
#include <Library/PrePiLib.h>
#include <Library/PrintLib.h>
#include <Library/PrePiHobListPointerLib.h>
@@ -128,3 +129,37 @@ CEntryPoint (
// DXE Core should always load and never return
ASSERT (FALSE);
}
+
+VOID
+RelocatePeCoffImage (
+ IN EFI_PEI_FV_HANDLE FwVolHeader,
+ IN PE_COFF_LOADER_READ_FILE ImageRead
+ )
+{
+ EFI_PEI_FILE_HANDLE FileHandle;
+ VOID *SectionData;
+ PE_COFF_LOADER_IMAGE_CONTEXT ImageContext;
+ EFI_STATUS Status;
+
+ FileHandle = NULL;
+ Status = FfsFindNextFile (EFI_FV_FILETYPE_SECURITY_CORE, FwVolHeader,
+ &FileHandle);
+ ASSERT_EFI_ERROR (Status);
+
+ Status = FfsFindSectionData (EFI_SECTION_PE32, FileHandle, &SectionData);
+ if (EFI_ERROR (Status)) {
+ Status = FfsFindSectionData (EFI_SECTION_TE, FileHandle, &SectionData);
+ }
+ ASSERT_EFI_ERROR (Status);
+
+ ZeroMem (&ImageContext, sizeof ImageContext);
+
+ ImageContext.Handle = (EFI_HANDLE)SectionData;
+ ImageContext.ImageRead = ImageRead;
+ PeCoffLoaderGetImageInfo (&ImageContext);
+
+ if (ImageContext.ImageAddress != (UINTN)SectionData) {
+ ImageContext.ImageAddress = (UINTN)SectionData;
+ PeCoffLoaderRelocateImage (&ImageContext);
+ }
+}
diff --git a/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S b/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
index 34d6abecb0ac..01623b6b3591 100644
--- a/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
+++ b/ArmVirtPkg/PrePi/AArch64/ModuleEntryPoint.S
@@ -9,40 +9,6 @@
#include <AsmMacroIoLibV8.h>
ASM_FUNC(_ModuleEntryPoint)
- //
- // We are built as a ET_DYN PIE executable, so we need to process all
- // relative relocations regardless of whether or not we are executing from
- // the same offset we were linked at. This is only possible if we are
- // running from RAM.
- //
- adr x8, __reloc_base
- adr x9, __reloc_start
- adr x10, __reloc_end
-
-.Lreloc_loop:
- cmp x9, x10
- bhs .Lreloc_done
-
- //
- // AArch64 uses the ELF64 RELA format, which means each entry in the
- // relocation table consists of
- //
- // UINT64 offset : the relative offset of the value that needs to
- // be relocated
- // UINT64 info : relocation type and symbol index (the latter is
- // not used for R_AARCH64_RELATIVE relocations)
- // UINT64 addend : value to be added to the value being relocated
- //
- ldp x11, x12, [x9], #24 // read offset into x11 and info into x12
- cmp x12, #0x403 // check info == R_AARCH64_RELATIVE?
- bne .Lreloc_loop // not a relative relocation? then skip
-
- ldr x12, [x9, #-8] // read addend into x12
- add x12, x12, x8 // add reloc base to addend to get relocated value
- str x12, [x11, x8] // write relocated value at offset
- b .Lreloc_loop
-.Lreloc_done:
-
bl ASM_PFX(DiscoverDramFromDt)
// Get ID of this CPU in Multicore system
@@ -170,15 +136,24 @@ ASM_PFX(DiscoverDramFromDt):
str x1, [x8]
str x7, [x9]
+ //
+ // The runtime address may be different from the link time address so fix
+ // up the PE/COFF relocations. Since we are calling a C function, use the
+ // window at the beginning of the FD image as a temp stack.
+ //
+ mov x0, x7
+ adr x1, PeCoffLoaderImageReadFromMemory
+ mov sp, x7
+ bl RelocatePeCoffImage
+
//
// Discover the memory size and offset from the DTB, and record in the
// respective PCDs. This will also return false if a corrupt DTB is
- // encountered. Since we are calling a C function, use the window at the
- // beginning of the FD image as a temp stack.
+ // encountered.
//
+ mov x0, x28
adr x1, PcdGet64 (PcdSystemMemoryBase)
adr x2, PcdGet64 (PcdSystemMemorySize)
- mov sp, x7
bl FindMemnode
cbz x0, .Lout
diff --git a/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S b/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
index 72d756fdb571..f0536c65eb52 100644
--- a/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
+++ b/ArmVirtPkg/PrePi/Arm/ModuleEntryPoint.S
@@ -9,38 +9,6 @@
#include <AsmMacroIoLib.h>
ASM_FUNC(_ModuleEntryPoint)
- //
- // We are built as a ET_DYN PIE executable, so we need to process all
- // relative relocations if we are executing from a different offset than we
- // were linked at. This is only possible if we are running from RAM.
- //
- ADRL (r4, __reloc_base)
- ADRL (r5, __reloc_start)
- ADRL (r6, __reloc_end)
-
-.Lreloc_loop:
- cmp r5, r6
- bhs .Lreloc_done
-
- //
- // AArch32 uses the ELF32 REL format, which means each entry in the
- // relocation table consists of
- //
- // UINT32 offset : the relative offset of the value that needs to
- // be relocated
- // UINT32 info : relocation type and symbol index (the latter is
- // not used for R_ARM_RELATIVE relocations)
- //
- ldrd r8, r9, [r5], #8 // read offset into r8 and info into r9
- cmp r9, #23 // check info == R_ARM_RELATIVE?
- bne .Lreloc_loop // not a relative relocation? then skip
-
- ldr r9, [r8, r4] // read addend into r9
- add r9, r9, r1 // add image base to addend to get relocated value
- str r9, [r8, r4] // write relocated value at offset
- b .Lreloc_loop
-.Lreloc_done:
-
// Do early platform specific actions
bl ASM_PFX(ArmPlatformPeiBootAction)
@@ -172,15 +140,24 @@ ASM_PFX(ArmPlatformPeiBootAction):
str r1, [r8]
str r5, [r7]
+ //
+ // The runtime address may be different from the link time address so fix
+ // up the PE/COFF relocations. Since we are calling a C function, use the
+ // window at the beginning of the FD image as a temp stack.
+ //
+ mov r0, r5
+ ADRL (r1, PeCoffLoaderImageReadFromMemory)
+ mov sp, r5
+ bl RelocatePeCoffImage
+
//
// Discover the memory size and offset from the DTB, and record in the
// respective PCDs. This will also return false if a corrupt DTB is
- // encountered. Since we are calling a C function, use the window at the
- // beginning of the FD image as a temp stack.
+ // encountered.
//
+ mov r0, r10
ADRL (r1, PcdGet64 (PcdSystemMemoryBase))
ADRL (r2, PcdGet64 (PcdSystemMemorySize))
- mov sp, r5
bl FindMemnode
teq r0, #0
beq .Lout
--
2.26.2
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