BaseTools/GenFw: Disable support for R_X86_64_32S

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=999

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Zenith432 <zenith432@users.sourceforge.net>
Reviewed-by: Liming Gao <liming.gao@intel.com>

1 files changed, 22 insertions, 1 deletions

diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c b/BaseTools/Source/C/GenFw/Elf64Convert.c
index 9035112..15da89c 100644
--- a/BaseTools/Source/C/GenFw/Elf64Convert.c
+++ b/BaseTools/Source/C/GenFw/Elf64Convert.c
@@ -1172,7 +1172,28 @@ WriteRelocations64 (
                 + (Rel->r_offset - SecShdr->sh_addr)),

                 EFI_IMAGE_REL_BASED_DIR64);

               break;

-            case R_X86_64_32S:

+            //

+            // R_X86_64_32 and R_X86_64_32S are ELF64 relocations emitted when using

+            //   the SYSV X64 ABI small non-position-independent code model.

+            //   R_X86_64_32 is used for unsigned 32-bit immediates with a 32-bit operand

+            //   size.  The value is either not extended, or zero-extended to 64 bits.

+            //   R_X86_64_32S is used for either signed 32-bit non-rip-relative displacements

+            //   or signed 32-bit immediates with a 64-bit operand size.  The value is

+            //   sign-extended to 64 bits.

+            //   EFI_IMAGE_REL_BASED_HIGHLOW is a PE relocation that uses 32-bit arithmetic

+            //   for rebasing an image.

+            //   EFI PE binaries declare themselves EFI_IMAGE_FILE_LARGE_ADDRESS_AWARE and

+            //   may load above 2GB.  If an EFI PE binary with a converted R_X86_64_32S

+            //   relocation is loaded above 2GB, the value will get sign-extended to the

+            //   negative part of the 64-bit address space.  The negative part of the 64-bit

+            //   address space is unmapped, so accessing such an address page-faults.

+            //   In order to support R_X86_64_32S, it is necessary to unset

+            //   EFI_IMAGE_FILE_LARGE_ADDRESS_AWARE, and the EFI PE loader must implement

+            //   this flag and abstain from loading such a PE binary above 2GB.

+            //   Since this feature is not supported, support for R_X86_64_32S (and hence

+            //   the small non-position-independent code model) is disabled.

+            //

+            // case R_X86_64_32S:

             case R_X86_64_32:

               VerboseMsg ("EFI_IMAGE_REL_BASED_HIGHLOW Offset: 0x%08X",

                 mCoffSectionsOffset[RelShdr->sh_info] + (Rel->r_offset - SecShdr->sh_addr));