[kvm-unit-tests PATCH v3 04/17] x86 UEFI: Copy code from GNU-EFI

[Zixuan Wang <zxwang42@gmail.com>]

From: Zixuan Wang <zixuanwang@google.com>

To build x86 test cases with UEFI, we need to borrow some source
code from GNU-EFI, which includes the initialization code and linker
scripts. This commit only copies the source code, without any
modification. These source code files are not used by KVM-Unit-Tests
in this commit.

The following source code is copied from GNU-EFI:
   1. x86/efi/elf_x86_64_efi.lds
   2. x86/efi/reloc_x86_64.c
   3. x86/efi/crt0-efi-x86_64.S

We put these EFI-related files under a new dir `x86/efi` because:
   1. EFI-related code is easy to find
   2. EFI-related code is separated from the original code in `x86/`
   3. EFI-related code can still reuse the Makefile and test case code
      in its parent dir `x86/`

GNU-EFI repo and version:
   GIT URL: https://git.code.sf.net/p/gnu-efi/code
   Commit ID: 4fe83e102674
   Website: https://sourceforge.net/p/gnu-efi/code/ci/4fe83e/tree/

Co-developed-by: Varad Gautam <varad.gautam@suse.com>
Signed-off-by: Varad Gautam <varad.gautam@suse.com>
Signed-off-by: Zixuan Wang <zixuanwang@google.com>
---
 x86/efi/README.md          |  25 ++++++++++
 x86/efi/crt0-efi-x86_64.S  |  79 +++++++++++++++++++++++++++++
 x86/efi/elf_x86_64_efi.lds |  77 ++++++++++++++++++++++++++++
 x86/efi/reloc_x86_64.c     | 100 +++++++++++++++++++++++++++++++++++++
 4 files changed, 281 insertions(+)
 create mode 100644 x86/efi/README.md
 create mode 100644 x86/efi/crt0-efi-x86_64.S
 create mode 100644 x86/efi/elf_x86_64_efi.lds
 create mode 100644 x86/efi/reloc_x86_64.c

diff --git a/x86/efi/README.md b/x86/efi/README.md
new file mode 100644
index 0000000..bc1f733
--- /dev/null
+++ b/x86/efi/README.md
@@ -0,0 +1,25 @@
+# EFI Startup Code and Linker Script
+
+This dir contains source code and linker script copied from
+[GNU-EFI](https://sourceforge.net/projects/gnu-efi/):
+   - crt0-efi-x86_64.S: startup code of an EFI application
+   - elf_x86_64_efi.lds: linker script to build an EFI application
+   - reloc_x86_64.c: position independent x86_64 ELF shared object relocator
+
+EFI application binaries should be relocatable as UEFI loads binaries to dynamic
+runtime addresses. To build such relocatable binaries, GNU-EFI utilizes the
+above-mentioned files in its build process:
+
+   1. build an ELF shared object and link it using linker script
+      `elf_x86_64_efi.lds` to organize the sections in a way UEFI recognizes
+   2. link the shared object with self-relocator `reloc_x86_64.c` that applies
+      dynamic relocations that may be present in the shared object
+   3. link the entry point code `crt0-efi-x86_64.S` that invokes self-relocator
+      and then jumps to EFI application's `efi_main()` function
+   4. convert the shared object to an EFI binary
+
+More details can be found in `GNU-EFI/README.gnuefi`, section "Building
+Relocatable Binaries".
+
+kvm-unit-tests follows a similar build process, but does not link with GNU-EFI
+library.
diff --git a/x86/efi/crt0-efi-x86_64.S b/x86/efi/crt0-efi-x86_64.S
new file mode 100644
index 0000000..eaf1656
--- /dev/null
+++ b/x86/efi/crt0-efi-x86_64.S
@@ -0,0 +1,79 @@
+/* The following code is copied from GNU-EFI/gnuefi/crt0-efi-x86_64.S
+
+   crt0-efi-x86_64.S - x86_64 EFI startup code.
+   Copyright (C) 1999 Hewlett-Packard Co.
+	Contributed by David Mosberger <davidm@hpl.hp.com>.
+   Copyright (C) 2005 Intel Co.
+	Contributed by Fenghua Yu <fenghua.yu@intel.com>.
+
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials
+      provided with the distribution.
+    * Neither the name of Hewlett-Packard Co. nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+    CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+    BE LIABLE FOR ANYDIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+*/
+	.text
+	.align 4
+
+	.globl _start
+_start:
+	subq $8, %rsp
+	pushq %rcx
+	pushq %rdx
+
+0:
+	lea ImageBase(%rip), %rdi
+	lea _DYNAMIC(%rip), %rsi
+
+	popq %rcx
+	popq %rdx
+	pushq %rcx
+	pushq %rdx
+	call _relocate
+
+	popq %rdi
+	popq %rsi
+
+	call efi_main
+	addq $8, %rsp
+
+.exit:	
+  	ret
+
+ 	// hand-craft a dummy .reloc section so EFI knows it's a relocatable executable:
+ 
+ 	.data
+dummy:	.long	0
+
+#define IMAGE_REL_ABSOLUTE	0
+ 	.section .reloc, "a"
+label1:
+	.long	dummy-label1				// Page RVA
+	.long	12					// Block Size (2*4+2*2), must be aligned by 32 Bits
+	.word	(IMAGE_REL_ABSOLUTE<<12) +  0		// reloc for dummy
+	.word	(IMAGE_REL_ABSOLUTE<<12) +  0		// reloc for dummy
+
diff --git a/x86/efi/elf_x86_64_efi.lds b/x86/efi/elf_x86_64_efi.lds
new file mode 100644
index 0000000..5eae376
--- /dev/null
+++ b/x86/efi/elf_x86_64_efi.lds
@@ -0,0 +1,77 @@
+/* Copied from GNU-EFI/gnuefi/elf_x86_64_efi.lds, licensed under GNU GPL */
+/* Same as elf_x86_64_fbsd_efi.lds, except for OUTPUT_FORMAT below - KEEP IN SYNC */
+OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
+OUTPUT_ARCH(i386:x86-64)
+ENTRY(_start)
+SECTIONS
+{
+  . = 0;
+  ImageBase = .;
+  /* .hash and/or .gnu.hash MUST come first! */
+  .hash : { *(.hash) }
+  .gnu.hash : { *(.gnu.hash) }
+  . = ALIGN(4096);
+  .eh_frame : 
+  { 
+    *(.eh_frame)
+  }
+  . = ALIGN(4096);
+  .text :
+  {
+   _text = .;
+   *(.text)
+   *(.text.*)
+   *(.gnu.linkonce.t.*)
+   . = ALIGN(16);
+  }
+  _etext = .;
+  _text_size = . - _text;
+  . = ALIGN(4096);
+  .reloc :
+  {
+   *(.reloc)
+  }
+  . = ALIGN(4096);
+  .data :
+  {
+   _data = .;
+   *(.rodata*)
+   *(.got.plt)
+   *(.got)
+   *(.data*)
+   *(.sdata)
+   /* the EFI loader doesn't seem to like a .bss section, so we stick
+      it all into .data: */
+   *(.sbss)
+   *(.scommon)
+   *(.dynbss)
+   *(.bss)
+   *(COMMON)
+   *(.rel.local)
+  }
+  .note.gnu.build-id : { *(.note.gnu.build-id) }
+
+  _edata = .;
+  _data_size = . - _etext;
+  . = ALIGN(4096);
+  .dynamic  : { *(.dynamic) }
+  . = ALIGN(4096);
+  .rela :
+  {
+    *(.rela.data*)
+    *(.rela.got)
+    *(.rela.stab)
+  }
+  . = ALIGN(4096);
+  .dynsym   : { *(.dynsym) }
+  . = ALIGN(4096);
+  .dynstr   : { *(.dynstr) }
+  . = ALIGN(4096);
+  .ignored.reloc :
+  {
+    *(.rela.reloc)
+    *(.eh_frame)
+    *(.note.GNU-stack)
+  }
+  .comment 0 : { *(.comment) }
+}
diff --git a/x86/efi/reloc_x86_64.c b/x86/efi/reloc_x86_64.c
new file mode 100644
index 0000000..d13b53e
--- /dev/null
+++ b/x86/efi/reloc_x86_64.c
@@ -0,0 +1,100 @@
+/* This file is copied from GNU-EFI/gnuefi/reloc_x86_64.c
+
+   reloc_x86_64.c - position independent x86_64 ELF shared object relocator
+   Copyright (C) 1999 Hewlett-Packard Co.
+	Contributed by David Mosberger <davidm@hpl.hp.com>.
+   Copyright (C) 2005 Intel Co.
+	Contributed by Fenghua Yu <fenghua.yu@intel.com>.
+
+    All rights reserved.
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions
+    are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials
+      provided with the distribution.
+    * Neither the name of Hewlett-Packard Co. nor the names of its
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+    CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+    BE LIABLE FOR ANYDIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
+    TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+    THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+    SUCH DAMAGE.
+*/
+
+#include <efi.h>
+#include <efilib.h>
+
+#include <elf.h>
+
+EFI_STATUS _relocate (long ldbase, Elf64_Dyn *dyn,
+		      EFI_HANDLE image EFI_UNUSED,
+		      EFI_SYSTEM_TABLE *systab EFI_UNUSED)
+{
+	long relsz = 0, relent = 0;
+	Elf64_Rel *rel = 0;
+	unsigned long *addr;
+	int i;
+
+	for (i = 0; dyn[i].d_tag != DT_NULL; ++i) {
+		switch (dyn[i].d_tag) {
+			case DT_RELA:
+				rel = (Elf64_Rel*)
+					((unsigned long)dyn[i].d_un.d_ptr
+					 + ldbase);
+				break;
+
+			case DT_RELASZ:
+				relsz = dyn[i].d_un.d_val;
+				break;
+
+			case DT_RELAENT:
+				relent = dyn[i].d_un.d_val;
+				break;
+
+			default:
+				break;
+		}
+	}
+
+        if (!rel && relent == 0)
+                return EFI_SUCCESS;
+
+	if (!rel || relent == 0)
+		return EFI_LOAD_ERROR;
+
+	while (relsz > 0) {
+		/* apply the relocs */
+		switch (ELF64_R_TYPE (rel->r_info)) {
+			case R_X86_64_NONE:
+				break;
+
+			case R_X86_64_RELATIVE:
+				addr = (unsigned long *)
+					(ldbase + rel->r_offset);
+				*addr += ldbase;
+				break;
+
+			default:
+				break;
+		}
+		rel = (Elf64_Rel*) ((char *) rel + relent);
+		relsz -= relent;
+	}
+	return EFI_SUCCESS;
+}
-- 
2.33.0