On Fri, Aug 27, 2021 at 03:12:08AM +0000, Zixuan Wang wrote: > 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@xxxxxxxx> > Signed-off-by: Varad Gautam <varad.gautam@xxxxxxxx> > Signed-off-by: Zixuan Wang <zixuanwang@xxxxxxxxxx> > --- > 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..256ef8c > --- /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. So, for AArch64, I also want to drop the gnu-efi dependency of my original PoC. My second PoC, which I haven't finished, took things a bit further than this does, though. I was integrating a PE/COFF header and linker script changes directly into the kvm-unit-tests code rather than copying these files over. Thanks, drew
