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>

diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c b/BaseTools/Source/C/GenFw/Elf64Convert.c
index 90351125893d083392947337c058e19d98cb3ac1..15da89c755fe755f6edbb92ec9f7be9172d85113 100644 (file)
--- 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)),\r
                 EFI_IMAGE_REL_BASED_DIR64);\r
               break;\r
-            case R_X86_64_32S:\r
+            //\r
+            // R_X86_64_32 and R_X86_64_32S are ELF64 relocations emitted when using\r
+            //   the SYSV X64 ABI small non-position-independent code model.\r
+            //   R_X86_64_32 is used for unsigned 32-bit immediates with a 32-bit operand\r
+            //   size.  The value is either not extended, or zero-extended to 64 bits.\r
+            //   R_X86_64_32S is used for either signed 32-bit non-rip-relative displacements\r
+            //   or signed 32-bit immediates with a 64-bit operand size.  The value is\r
+            //   sign-extended to 64 bits.\r
+            //   EFI_IMAGE_REL_BASED_HIGHLOW is a PE relocation that uses 32-bit arithmetic\r
+            //   for rebasing an image.\r
+            //   EFI PE binaries declare themselves EFI_IMAGE_FILE_LARGE_ADDRESS_AWARE and\r
+            //   may load above 2GB.  If an EFI PE binary with a converted R_X86_64_32S\r
+            //   relocation is loaded above 2GB, the value will get sign-extended to the\r
+            //   negative part of the 64-bit address space.  The negative part of the 64-bit\r
+            //   address space is unmapped, so accessing such an address page-faults.\r
+            //   In order to support R_X86_64_32S, it is necessary to unset\r
+            //   EFI_IMAGE_FILE_LARGE_ADDRESS_AWARE, and the EFI PE loader must implement\r
+            //   this flag and abstain from loading such a PE binary above 2GB.\r
+            //   Since this feature is not supported, support for R_X86_64_32S (and hence\r
+            //   the small non-position-independent code model) is disabled.\r
+            //\r
+            // case R_X86_64_32S:\r
             case R_X86_64_32:\r
               VerboseMsg ("EFI_IMAGE_REL_BASED_HIGHLOW Offset: 0x%08X",\r
                 mCoffSectionsOffset[RelShdr->sh_info] + (Rel->r_offset - SecShdr->sh_addr));\r