From a210b02b15d68bfe38651295f35edb1a21cef475 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 27 Mar 2015 08:11:19 -0700 Subject: [PATCH] efi: chainloader: implement an UEFI Exit service Upstream-Status: Inappropriate [embedded specific] Implement an UEFI Exit service for shim in grub. When exiting, grub will call the UEFI boot-time service Exit. The effect of this is that UEFI will jump to the entry point of the UEFI started image. If we execute an image using shim within grub, shim takes care of loading/parsing/relocating/executing the image. Under this scenario, we also need to take care of the Exit call. Thus, we need to reimplement the function to make sure we perform a jump to the instruction after which shim executed the image. Once we have taken care of the exit of the shim-executed image the system Exit call is restored. Signed-off-by: Ricardo Neri [lz: Adapt git shortlog.] Signed-off-by: Li Zhou --- grub-core/kern/x86_64/efi/callwrap.S | 23 +++++++++++++++++++++++ include/grub/efi/api.h | 4 ++++ 2 files changed, 27 insertions(+) diff --git a/grub-core/kern/x86_64/efi/callwrap.S b/grub-core/kern/x86_64/efi/callwrap.S index 1337fd9..b849c2c 100644 --- a/grub-core/kern/x86_64/efi/callwrap.S +++ b/grub-core/kern/x86_64/efi/callwrap.S @@ -48,6 +48,26 @@ FUNCTION(efi_wrap_1) addq $40, %rsp ret +FUNCTION(efi_call_foo) + pushq %rbp + pushq %r12 + pushq %r13 + pushq %r14 + pushq %r15 + movq %rsp, saved_sp(%rip) + subq $48, %rsp + mov %rsi, %rcx + call *%rdi + +FUNCTION(efi_shim_exit) + movq saved_sp(%rip), %rsp + popq %r15 + popq %r14 + popq %r13 + popq %r12 + popq %rbp + ret + FUNCTION(efi_wrap_2) subq $40, %rsp mov %rsi, %rcx @@ -127,3 +147,6 @@ FUNCTION(efi_wrap_10) call *%rdi addq $88, %rsp ret + + .data +saved_sp: .quad 0 diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h index f1a5221..de3bbbd 100644 --- a/include/grub/efi/api.h +++ b/include/grub/efi/api.h @@ -1776,6 +1776,10 @@ typedef struct grub_efi_rng_protocol grub_efi_rng_protocol_t; grub_uint64_t EXPORT_FUNC(efi_wrap_0) (void *func); grub_uint64_t EXPORT_FUNC(efi_wrap_1) (void *func, grub_uint64_t arg1); +grub_efi_status_t EXPORT_FUNC(efi_shim_exit) (grub_efi_handle_t handle, grub_efi_status_t exit_status, + grub_efi_uintn_t exit_data_size, grub_efi_char16_t *exit_data) __attribute__((noreturn)); +grub_uint64_t EXPORT_FUNC(efi_call_foo) (void *func, grub_uint64_t arg1, + grub_uint64_t arg2); grub_uint64_t EXPORT_FUNC(efi_wrap_2) (void *func, grub_uint64_t arg1, grub_uint64_t arg2); grub_uint64_t EXPORT_FUNC(efi_wrap_3) (void *func, grub_uint64_t arg1, -- 2.17.1