We are going to reduce reserved memory consumption by page table buffer, then OS can have more available memory to use. Take PhysicalAddressBits = 48 and 2MB page granularity as example, 1:1 Virtual to Physical identity mapping page table buffer needs to be ((512 + 1) * 512 + 1) * 4096 = 1075843072 bytes = 0x40201000 bytes. The code is updated to build 4G page table by default and only use 8 extra pages to handles > 4G request by page fault. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Star Zeng <star.zeng@intel.com> Reviewed-by: Jiewen Yao <jiewen.yao@intel.com> git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18069 6f19259b-4bc3-4df7-8a09-765794883524
88 lines
2.3 KiB
NASM
88 lines
2.3 KiB
NASM
;; @file
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; This is the assembly code for page fault handler hook.
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;
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; Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
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;
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution. The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;
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;;
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EXTERN PageFaultHandler:PROC
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.code
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PageFaultHandlerHook PROC
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add rsp, -10h
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; save rax
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mov [rsp + 08h], rax
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;push rax ; save all volatile registers
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push rcx
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push rdx
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push r8
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push r9
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push r10
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push r11
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; save volatile fp registers
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; 68h + 08h(for alignment)
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add rsp, -70h
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stmxcsr [rsp + 60h]
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movdqa [rsp + 0h], xmm0
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movdqa [rsp + 10h], xmm1
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movdqa [rsp + 20h], xmm2
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movdqa [rsp + 30h], xmm3
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movdqa [rsp + 40h], xmm4
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movdqa [rsp + 50h], xmm5
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add rsp, -20h
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call PageFaultHandler
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add rsp, 20h
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; load volatile fp registers
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ldmxcsr [rsp + 60h]
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movdqa xmm0, [rsp + 0h]
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movdqa xmm1, [rsp + 10h]
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movdqa xmm2, [rsp + 20h]
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movdqa xmm3, [rsp + 30h]
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movdqa xmm4, [rsp + 40h]
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movdqa xmm5, [rsp + 50h]
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add rsp, 70h
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pop r11
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pop r10
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pop r9
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pop r8
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pop rdx
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pop rcx
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;pop rax ; restore all volatile registers
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add rsp, 10h
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; rax returned from PageFaultHandler is NULL or OriginalHandler address
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; NULL if the page fault is handled by PageFaultHandler
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; OriginalHandler address if the page fault is not handled by PageFaultHandler
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test rax, rax
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; save OriginalHandler address
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mov [rsp - 10h], rax
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; restore rax
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mov rax, [rsp - 08h]
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jz @F
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; jump to OriginalHandler
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jmp qword ptr [rsp - 10h]
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@@:
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add rsp, 08h ; skip error code for PF
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iretq
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PageFaultHandlerHook ENDP
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END
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