*** Background *** As more PE format kernel images are introduced, it post challenge to kexec to cope with the new format. In my attempt to add support for arm64 zboot image in the kernel [1], Ard suggested using an emulator to tackle this issue. Last year, when Jan tried to introduce UKI support in the kernel [2], Ard mentioned the emulator approach again [3] After discussion, Ard's approach seems to be a more promising solution to handle PE format kernels once and for all. This series follows that approach and implements an emulator to emulate EFI boot time services, allowing the efistub kernel to self-extract and boot. *** Overview of implement *** The whole model consits of three parts: -1. The emulator It is a self-relocatable PIC code, which is finally linked into kernel, but not export any internal symbol to kernel. It mainly contains: a PE file parser, which loads PE format kernel, a group of functions to emulate efi boot service. -2. inside kernel, PE-format loader Its main task is to set up two extra kexec_segment, one for emulator, the other for passing information from the first kernel to emulator. -3. set up identity mapping only for the memory used by the emulator. Here it relies on kimage_alloc_control_pages() to get pages, which will not stamped during the process of kexec relocate (cp from src to dst). And since the mapping only covers a small range of memory, it cost small amount memory. *** To do *** Currently, it only works on arm64 _zboot_ image on arm64 virt machine. For arm64 UKI, I have not completed it. But it should be easy to archieve by implementing EFI_LOAD_FILE2_PROTOCOL.LoadFile(). And with a slightly improvement, it would work on x86. Besides that, as POC, I skip four functions in efistub: setup_graphics(), efi_random_get_seed() and efi_enable_reset_attack_mitigation(), efi_retrieve_eventlog(). Hence skipping the corresponding boot services. Also, this series does not implement a memory allocator, which I plan to implement with the help of bitmap. About console, currently it hard code for arm64 virt machine, later it should extract the information through ACPI table. [1]: https://lore.kernel.org/linux-arm-kernel/ZBvKSis+dfnqa+Vz@xxxxxxxxxxxxxxxxxxxxxxxxxx/T/#m42abb0ad3c10126b8b3bfae8a596deb707d6f76e [2]: https://lore.kernel.org/lkml/20230918173607.421d2616@rotkaeppchen/T/ [3]: https://lore.kernel.org/lkml/20230918173607.421d2616@rotkaeppchen/T/#mc60aa591cb7616ceb39e1c98f352383f9ba6e985 Cc: Ard Biesheuvel <ardb@xxxxxxxxxx> Cc: Jan Hendrik Farr <kernel@xxxxxxxx> Cc: Philipp Rudo <prudo@xxxxxxxxxx> Cc: Lennart Poettering <mzxreary@xxxxxxxxxxx> Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx To: kexec@xxxxxxxxxxxxxxxxxxx To: linux-efi@xxxxxxxxxxxxxxx Pingfan Liu (7): efi/libstub: Ask efi_random_alloc() to skip unusable memory debug/libstub: cheats to step around some boot service efi/emulator: Initial rountines to emulate EFI boot time service efi/emulator: Turn on mmu for arm64 arm64: mm: Change to prototype of arm64: kexec: Prepare page table for emulator kexec: Introduce kexec_pe_image to parse and load PE file arch/arm64/include/asm/kexec.h | 3 + arch/arm64/include/asm/mmu.h | 6 + arch/arm64/kernel/Makefile | 2 +- arch/arm64/kernel/kexec_image.c | 1 + arch/arm64/kernel/kexec_pe_image.c | 519 ++++++++++++++++++ arch/arm64/kernel/machine_kexec.c | 90 ++- arch/arm64/kernel/machine_kexec_file.c | 1 + arch/arm64/mm/mmu.c | 67 ++- drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/efi_emulator/Makefile | 98 ++++ .../firmware/efi/efi_emulator/amba-pl011.c | 80 +++ .../efi_emulator/arm64_emulator_service.lds | 45 ++ .../firmware/efi/efi_emulator/arm64_proc.S | 172 ++++++ .../firmware/efi/efi_emulator/config_table.c | 23 + drivers/firmware/efi/efi_emulator/core.c | 211 +++++++ drivers/firmware/efi/efi_emulator/earlycon.h | 19 + .../firmware/efi/efi_emulator/efi_emulator.S | 12 + drivers/firmware/efi/efi_emulator/emulator.h | 66 +++ drivers/firmware/efi/efi_emulator/entry.c | 64 +++ drivers/firmware/efi/efi_emulator/head.S | 10 + drivers/firmware/efi/efi_emulator/initrd.c | 15 + drivers/firmware/efi/efi_emulator/lib.c | 73 +++ drivers/firmware/efi/efi_emulator/memory.c | 27 + .../firmware/efi/efi_emulator/memory_api.c | 73 +++ drivers/firmware/efi/efi_emulator/misc.c | 76 +++ drivers/firmware/efi/efi_emulator/pe_loader.c | 124 +++++ drivers/firmware/efi/efi_emulator/printf.c | 389 +++++++++++++ .../efi/efi_emulator/runtime_service.c | 28 + .../firmware/efi/libstub/efi-stub-helper.c | 3 + drivers/firmware/efi/libstub/efi-stub.c | 2 + drivers/firmware/efi/libstub/random.c | 2 + drivers/firmware/efi/libstub/randomalloc.c | 5 + drivers/firmware/efi/libstub/tpm.c | 4 + include/linux/efi_emulator.h | 46 ++ include/linux/kexec.h | 5 + 35 files changed, 2327 insertions(+), 35 deletions(-) create mode 100644 arch/arm64/kernel/kexec_pe_image.c create mode 100644 drivers/firmware/efi/efi_emulator/Makefile create mode 100644 drivers/firmware/efi/efi_emulator/amba-pl011.c create mode 100644 drivers/firmware/efi/efi_emulator/arm64_emulator_service.lds create mode 100644 drivers/firmware/efi/efi_emulator/arm64_proc.S create mode 100644 drivers/firmware/efi/efi_emulator/config_table.c create mode 100644 drivers/firmware/efi/efi_emulator/core.c create mode 100644 drivers/firmware/efi/efi_emulator/earlycon.h create mode 100644 drivers/firmware/efi/efi_emulator/efi_emulator.S create mode 100644 drivers/firmware/efi/efi_emulator/emulator.h create mode 100644 drivers/firmware/efi/efi_emulator/entry.c create mode 100644 drivers/firmware/efi/efi_emulator/head.S create mode 100644 drivers/firmware/efi/efi_emulator/initrd.c create mode 100644 drivers/firmware/efi/efi_emulator/lib.c create mode 100644 drivers/firmware/efi/efi_emulator/memory.c create mode 100644 drivers/firmware/efi/efi_emulator/memory_api.c create mode 100644 drivers/firmware/efi/efi_emulator/misc.c create mode 100644 drivers/firmware/efi/efi_emulator/pe_loader.c create mode 100644 drivers/firmware/efi/efi_emulator/printf.c create mode 100644 drivers/firmware/efi/efi_emulator/runtime_service.c create mode 100644 include/linux/efi_emulator.h -- 2.41.0
