50 lines
961 B
ArmAsm
50 lines
961 B
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* EFI call stub for IA32.
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*
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* This stub allows us to make EFI calls in physical mode with interrupts
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* turned off.
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*/
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#include <linux/linkage.h>
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#include <linux/init.h>
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#include <asm/page_types.h>
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__INIT
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SYM_FUNC_START(efi_call_svam)
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push 8(%esp)
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push 8(%esp)
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push %ecx
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push %edx
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/*
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* Switch to the flat mapped alias of this routine, by jumping to the
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* address of label '1' after subtracting PAGE_OFFSET from it.
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*/
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movl $1f, %edx
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subl $__PAGE_OFFSET, %edx
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jmp *%edx
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1:
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/* disable paging */
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movl %cr0, %edx
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andl $0x7fffffff, %edx
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movl %edx, %cr0
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/* convert the stack pointer to a flat mapped address */
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subl $__PAGE_OFFSET, %esp
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/* call the EFI routine */
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call *(%eax)
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/* convert ESP back to a kernel VA, and pop the outgoing args */
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addl $__PAGE_OFFSET + 16, %esp
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/* re-enable paging */
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movl %cr0, %edx
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orl $0x80000000, %edx
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movl %edx, %cr0
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ret
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SYM_FUNC_END(efi_call_svam)
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