Fixed GCC 4.4 build issue. Also fixed issue where upper 32-bits may be lost during...

[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / DisablePaging64.S

diff --git a/MdePkg/Library/BaseLib/X64/DisablePaging64.S b/MdePkg/Library/BaseLib/X64/DisablePaging64.S
index a55059e3bec99bd7c4c7d9f80dde23f012a3f3a1..ce9e9de533f3f1fcb1fbd9fd24163c2157e28dec 100644 (file)
--- a/MdePkg/Library/BaseLib/X64/DisablePaging64.S
+++ b/MdePkg/Library/BaseLib/X64/DisablePaging64.S
@@ -1,6 +1,6 @@
 #------------------------------------------------------------------------------\r
 #\r
-# Copyright (c) 2006 - 2008, Intel Corporation\r
+# Copyright (c) 2006 - 2009, Intel Corporation\r
 # All rights reserved. This program and the accompanying materials\r
 # are licensed and made available under the terms and conditions of the BSD License\r
 # which accompanies this distribution.  The full text of the license may be found at\r
@@ -28,29 +28,45 @@
 # EFIAPI\r
 # InternalX86DisablePaging64 (\r
 #   IN      UINT16                    Cs,\r
-#   IN      UINT64                    EntryPoint,\r
-#   IN      UINT64                    Context1,  OPTIONAL\r
+#   IN      UINT32                    EntryPoint,\r
+#   IN      UINT32                    Context1,  OPTIONAL\r
 #   IN      UINT32                    Context2,  OPTIONAL\r
-#   IN      UINT64                    NewStack\r
+#   IN      UINT32                    NewStack\r
 #   );\r
 #------------------------------------------------------------------------------\r
 \r
-.global ASM_PFX(InternalX86DisablePaging64)\r
+ASM_GLOBAL ASM_PFX(InternalX86DisablePaging64)\r
 ASM_PFX(InternalX86DisablePaging64):\r
     cli    \r
-    shl    $0x20,%rcx                     # rcx[32..47] <- Cs\r
-    lea    L1, %eax\r
+    lea    L1(%rip), %rsi                 # rsi <- The start address of transition code\r
+    mov    0x28(%rsp), %edi               # rdi <- New stack\r
+    lea    _mTransitionEnd(%rip), %rax    # rax <- end of transition code\r
+    sub    %rsi, %rax                     # rax <- The size of transition piece code\r
+    add    $4, %rax                       # round rax up to the next 4 byte boundary\r
+    and    $0xfc, %al\r
+    sub    %rax, %rdi                     # rdi <- use stack to hold transition code \r
+    mov    %edi, %r10d                    # r10 <- The start address of transicition code below 4G\r
+    push   %rcx                           # save rcx to stack\r
+    mov    %rax, %rcx                     # rcx <- The size of transition piece code\r
+    rep\r
+    movsb                                 # copy transition code to (new stack - 64byte) below 4G\r
+    pop    %rcx                           # restore rcx\r
+   \r
     mov    %r8d, %esi \r
-    or     %rax, %rcx                     # rcx[0..47] <- Cs:@F\r
     mov    %r9d, %edi \r
-    mov    0x28(%rsp), %eax               # eax <- New Stack\r
-    push   %rcx\r
-    ret                                   # switch to compatibility mode\r
+    mov    %r10d, %eax\r
+    sub    $4, %eax\r
+    push   %rcx                           # push Cs to stack\r
+    push   %r10                           # push address of transition code on stack  \r
+    .byte  0x48, 0xcb                     # retq: Use far return to load CS register from stack\r
+                                          # (Use raw byte code since some GNU assemblers generates incorrect code for "retq")  \r
 L1:\r
     mov    %eax,%esp                      # set up new stack\r
     mov    %cr0,%rax\r
-    btr    $0x1f,%eax\r
+    btr    $0x1f,%eax                     # clear CR0.PG\r
     mov    %rax,%cr0                      # disable paging\r
+\r
+    mov    %edx,%ebx                      # save EntryPoint to ebx, for rdmsr will overwrite edx\r
     mov    $0xc0000080,%ecx\r
     rdmsr  \r
     and    $0xfe,%ah                      # clear LME\r
@@ -60,6 +76,7 @@ L1:
     mov    %rax,%cr4\r
     push   %rdi                           # push Context2\r
     push   %rsi                           # push Context1\r
-    callq  *%rdx                          # transfer control to EntryPoint\r
+    callq  *%rbx                          # transfer control to EntryPoint\r
     jmp    .                              # no one should get here\r
 \r
+_mTransitionEnd :\r