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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)
|
|
