Instead of storing the return address in a global variable when calling a 32-bit EFI service from the 64-bit stub, avoid the indirection via efi_exit32, and take the return address from the stack. Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- arch/x86/boot/compressed/efi_thunk_64.S | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/arch/x86/boot/compressed/efi_thunk_64.S b/arch/x86/boot/compressed/efi_thunk_64.S index 593913692d16..6d95eb6b8912 100644 --- a/arch/x86/boot/compressed/efi_thunk_64.S +++ b/arch/x86/boot/compressed/efi_thunk_64.S @@ -10,7 +10,7 @@ * needs to be able to service interrupts. * * On the plus side, we don't have to worry about mangling 64-bit - * addresses into 32-bits because we're executing with an identify + * addresses into 32-bits because we're executing with an identity * mapped pagetable and haven't transitioned to 64-bit virtual addresses * yet. */ @@ -28,7 +28,7 @@ SYM_FUNC_START(efi64_thunk) push %rbx subq $8, %rsp - leaq efi_exit32(%rip), %rax + leaq 1f(%rip), %rax movl %eax, 4(%rsp) leaq efi_gdt64(%rip), %rax movl %eax, (%rsp) @@ -55,9 +55,6 @@ SYM_FUNC_START(efi64_thunk) sgdt save_gdt(%rip) - leaq 1f(%rip), %rbx - movq %rbx, func_rt_ptr(%rip) - /* * Switch to gdt with 32-bit segments. This is the firmware GDT * that was installed when the kernel started executing. This @@ -72,6 +69,7 @@ SYM_FUNC_START(efi64_thunk) lretq 1: addq $32, %rsp + movq %rdi, %rax lgdt save_gdt(%rip) @@ -99,13 +97,6 @@ SYM_FUNC_START(efi64_thunk) ret SYM_FUNC_END(efi64_thunk) -SYM_FUNC_START_LOCAL(efi_exit32) - movq func_rt_ptr(%rip), %rax - push %rax - mov %rdi, %rax - ret -SYM_FUNC_END(efi_exit32) - .code32 /* * EFI service pointer must be in %edi. @@ -186,8 +177,6 @@ SYM_DATA_START_LOCAL(save_gdt) .quad 0 SYM_DATA_END(save_gdt) -SYM_DATA_LOCAL(func_rt_ptr, .quad 0) - SYM_DATA_START(efi_gdt64) .word efi_gdt64_end - efi_gdt64 .long 0 /* Filled out by user */ -- 2.20.1
