/* SPDX-License-Identifier: GPL-2.0-only */ /* * Calls a x86_64 function from x86_32 context. * Must not be directly invoked from C code! */ .text .code32 .section ".text.long_mode_call_3arg", "ax", @progbits .global long_mode_call_3arg long_mode_call_3arg: /* Function to call is passed in EAX. */ /* Backup registers */ pushal /* Backup stack pointer */ mov %esp, %ebp /* Enter long mode, preserves ebx */ #include /* Align stack */ movabs $0xfffffffffffffff0, %rax andq %rax, %rsp movl 28(%rbp), %ebx /* Function to call */ movl 36(%rbp), %edi /* 1st arg */ movl 40(%rbp), %esi /* 2nd arg */ movl 44(%rbp), %edx /* 3rd arg */ call *%rbx /* Store return value on stack. popal will fetch it. */ mov %eax, 28(%rbp) shr $32, %rax movl %eax, 24(%rbp) #include /* Restore stack pointer */ mov %ebp, %esp /* Restore registers */ popal ret