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/* SPDX-License-Identifier: GPL-2.0 */
/*
* EFI call stub for IA32.
*
* This stub allows us to make EFI calls in physical mode with interrupts
* turned off.
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/asm-offsets.h>
#include <asm/page_types.h>
__INIT
SYM_FUNC_START(efi_call_svam)
push %ebp
movl %esp, %ebp
push %ebx
push 16(%esp)
push 16(%esp)
push %ecx
push %edx
movl %eax, %ebx // &systab_phys->runtime
/*
* Switch to the flat mapped alias of this routine, by jumping to the
* address of label '1' after subtracting PAGE_OFFSET from it.
*/
movl $1f, %edx
subl $__PAGE_OFFSET, %edx
jmp *%edx
1:
/* disable paging */
movl %cr0, %edx
andl $0x7fffffff, %edx
movl %edx, %cr0
/* convert the stack pointer to a flat mapped address */
subl $__PAGE_OFFSET, %esp
/* call the EFI routine */
movl (%eax), %eax
call *EFI_svam(%eax)
/* grab the virtually remapped EFI runtime services table pointer */
movl (%ebx), %ecx
movl 36(%esp), %edx // &efi.runtime
movl %ecx, (%edx)
/* re-enable paging */
movl %cr0, %edx
orl $0x80000000, %edx
movl %edx, %cr0
movl 16(%esp), %ebx
leave
ret
SYM_FUNC_END(efi_call_svam)
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