[edk2-devel] [PATCH v5 2/5] UefiCpuPkg/ResetVector: Simplify page table creation in ResetVector

[Zhiguang Liu]

Currently, page table creation has many hard-code values about the
offset to the start of page table. To simplify it, add Labels such
as Pml4, Pdp and Pd, so that we can remove many hard-code values

Cc: Eric Dong <eric.dong at intel.com>
Cc: Ray Ni <ray.ni at intel.com>
Cc: Rahul Kumar <rahul1.kumar at intel.com>
Cc: Gerd Hoffmann <kraxel at redhat.com>
Cc: Debkumar De <debkumar.de at intel.com>
Cc: Catharine West <catharine.west at intel.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu at intel.com>
---
 .../ResetVector/Vtf0/Ia32/PageTables64.asm    |  4 +--
 .../ResetVector/Vtf0/X64/PageTables1G.asm     | 18 ++++------
 .../ResetVector/Vtf0/X64/PageTables2M.asm     | 34 ++++++++-----------
 3 files changed, 24 insertions(+), 32 deletions(-)

diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm b/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
index 87a4125d4b..f188da20ba 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/Ia32/PageTables64.asm
@@ -2,7 +2,7 @@
 ; @file
 ; Sets the CR3 register for 64-bit paging
 ;
-; Copyright (c) 2008 - 2013, Intel Corporation. All rights reserved.<BR>
+; Copyright (c) 2008 - 2023, Intel Corporation. All rights reserved.<BR>
 ; SPDX-License-Identifier: BSD-2-Clause-Patent
 ;
 ;------------------------------------------------------------------------------
@@ -17,7 +17,7 @@ SetCr3ForPageTables64:
     ;
     ; These pages are built into the ROM image in X64/PageTables.asm
     ;
-    mov     eax, ADDR_OF(TopLevelPageDirectory)
+    mov     eax, ADDR_OF(Pml4)
     mov     cr3, eax
 
     OneTimeCallRet SetCr3ForPageTables64
diff --git a/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables1G.asm b/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables1G.asm
index 20a61f949c..f5b8da0015 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables1G.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables1G.asm
@@ -29,35 +29,31 @@ BITS    64
                         PAGE_PRESENT + \
                         PAGE_SIZE)
 
-%define PGTBLS_OFFSET(x) ((x) - TopLevelPageDirectory)
-%define PGTBLS_ADDR(x) (ADDR_OF(TopLevelPageDirectory) + (x))
-
 ;
 ; Page table non-leaf entry
 ;
-%define PAGE_NLE(offset) (ADDR_OF(TopLevelPageDirectory) + (offset) + \
+%define PAGE_NLE(address) (ADDR_OF(address) + \
                     PAGE_NLE_ATTR)
 
 %define PAGE_PDPTE_1GB(x) ((x << 30) + PAGE_BLE_ATTR)
 
 ALIGN 16
 
-TopLevelPageDirectory:
-
+Pml4:
     ;
-    ; Top level Page Directory Pointers (1 * 512GB entry)
+    ; PML4 (1 * 512GB entry)
     ;
-    DQ      PAGE_NLE(0x1000)
+    DQ      PAGE_NLE(Pdp)
+    TIMES   0x1000 - ($ - Pml4) DB 0
 
-    TIMES 0x1000-PGTBLS_OFFSET($) DB 0
+Pdp:
     ;
-    ; Next level Page Directory Pointers (512 * 1GB entries => 512GB)
+    ; Page-directory pointer table (512 * 1GB entries => 512GB)
     ;
 %assign i 0
 %rep      512
     DQ    PAGE_PDPTE_1GB(i)
     %assign i i+1
 %endrep
-    TIMES 0x2000-PGTBLS_OFFSET($) DB 0
 
 EndOfPageTables:
diff --git a/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables2M.asm b/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables2M.asm
index 1221b023fe..731dabad4d 100644
--- a/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables2M.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/X64/PageTables2M.asm
@@ -28,36 +28,32 @@ BITS    64
                         PAGE_READ_WRITE + \
                         PAGE_PRESENT)
 
-%define PGTBLS_OFFSET(x) ((x) - TopLevelPageDirectory)
-%define PGTBLS_ADDR(x) (ADDR_OF(TopLevelPageDirectory) + (x))
-
-%define PAGE_NLE(offset) (ADDR_OF(TopLevelPageDirectory) + (offset) + \
+%define PAGE_NLE(address) (ADDR_OF(address) + \
                     PAGE_NLE_ATTR)
 %define PAGE_PDE_2MB(x) ((x << 21) + PAGE_BLE_ATTR)
 
-TopLevelPageDirectory:
-
+Pml4:
     ;
-    ; Top level Page Directory Pointers (1 * 512GB entry)
+    ; PML4 (1 * 512GB entry)
     ;
-    DQ      PAGE_NLE(0x1000)
-
+    DQ      PAGE_NLE(Pdp)
+    TIMES   0x1000 - ($ - Pml4) DB 0
 
+Pdp:
     ;
-    ; Next level Page Directory Pointers (4 * 1GB entries => 4GB)
+    ; Page-directory pointer table (4 * 1GB entries => 4GB)
     ;
-    TIMES 0x1000-PGTBLS_OFFSET($) DB 0
-
-    DQ      PAGE_NLE(0x2000)
-    DQ      PAGE_NLE(0x3000)
-    DQ      PAGE_NLE(0x4000)
-    DQ      PAGE_NLE(0x5000)
+    DQ      PAGE_NLE(Pd)
+    DQ      PAGE_NLE(Pd + 0x1000)
+    DQ      PAGE_NLE(Pd + 0x2000)
+    DQ      PAGE_NLE(Pd + 0x3000)
+    TIMES   0x1000 - ($ - Pdp) DB 0
 
+Pd:
     ;
-    ; Page Table Entries (2048 * 2MB entries => 4GB)
+    ; Page-Directory (2048 * 2MB entries => 4GB)
+    ; Four pages below, each is pointed by one entry in Pdp.
     ;
-    TIMES 0x2000-PGTBLS_OFFSET($) DB 0
-
 %assign i 0
 %rep    0x800
     DQ      PAGE_PDE_2MB(i)
-- 
2.31.1.windows.1



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