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60 lines
1.2 KiB
60 lines
1.2 KiB
/* 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/asm-offsets.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 %ebp |
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movl %esp, %ebp |
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push %ebx |
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push 16(%esp) |
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push 16(%esp) |
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push %ecx |
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push %edx |
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movl %eax, %ebx // &systab_phys->runtime |
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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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movl (%eax), %eax |
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call *EFI_svam(%eax) |
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/* grab the virtually remapped EFI runtime services table pointer */ |
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movl (%ebx), %ecx |
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movl 36(%esp), %edx // &efi.runtime |
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movl %ecx, (%edx) |
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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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movl 16(%esp), %ebx |
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leave |
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ret |
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SYM_FUNC_END(efi_call_svam)
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