Removed MdePkg usage of ModuleName: in file headers

[mirror_edk2.git] / MdePkg / Library / BaseLib / X64 / Non-existing.c

diff --git a/MdePkg/Library/BaseLib/X64/Non-existing.c b/MdePkg/Library/BaseLib/X64/Non-existing.c
index fc4fd4389854f2c0befda831e03d94f844f62e0e..4952916777204330f6570d65657f289dafd3ac1c 100644 (file)
--- a/MdePkg/Library/BaseLib/X64/Non-existing.c
+++ b/MdePkg/Library/BaseLib/X64/Non-existing.c
@@ -10,12 +10,43 @@
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
 \r
-  Module Name:  Non-existing.c\r
-\r
 **/\r
 \r
 #include "../BaseLibInternals.h"\r
 \r
+/**\r
+  Enables the 32-bit paging mode on the CPU.\r
+\r
+  Enables the 32-bit paging mode on the CPU. CR0, CR3, CR4, and the page tables\r
+  must be properly initialized prior to calling this service. This function\r
+  assumes the current execution mode is 32-bit protected mode. This function is\r
+  only available on IA-32. After the 32-bit paging mode is enabled, control is\r
+  transferred to the function specified by EntryPoint using the new stack\r
+  specified by NewStack and passing in the parameters specified by Context1 and\r
+  Context2. Context1 and Context2 are optional and may be NULL. The function\r
+  EntryPoint must never return.\r
+\r
+  There are a number of constraints that must be followed before calling this\r
+  function:\r
+  1)  Interrupts must be disabled.\r
+  2)  The caller must be in 32-bit protected mode with flat descriptors. This\r
+      means all descriptors must have a base of 0 and a limit of 4GB.\r
+  3)  CR0 and CR4 must be compatible with 32-bit protected mode with flat\r
+      descriptors.\r
+  4)  CR3 must point to valid page tables that will be used once the transition\r
+      is complete, and those page tables must guarantee that the pages for this\r
+      function and the stack are identity mapped.\r
+\r
+  @param  EntryPoint  A pointer to function to call with the new stack after\r
+                      paging is enabled.\r
+  @param  Context1    A pointer to the context to pass into the EntryPoint\r
+                      function as the first parameter after paging is enabled.\r
+  @param  Context2    A pointer to the context to pass into the EntryPoint\r
+                      function as the second parameter after paging is enabled.\r
+  @param  NewStack    A pointer to the new stack to use for the EntryPoint\r
+                      function after paging is enabled.\r
+\r
+**/\r
 VOID\r
 EFIAPI\r
 InternalX86EnablePaging32 (\r
@@ -25,9 +56,42 @@ InternalX86EnablePaging32 (
   IN      VOID                      *NewStack\r
   )\r
 {\r
+  //\r
+  // This function cannot work on X64 platform\r
+  //\r
   ASSERT (FALSE);\r
 }\r
 \r
+/**\r
+  Disables the 32-bit paging mode on the CPU.\r
+\r
+  Disables the 32-bit paging mode on the CPU and returns to 32-bit protected\r
+  mode. This function assumes the current execution mode is 32-paged protected\r
+  mode. This function is only available on IA-32. After the 32-bit paging mode\r
+  is disabled, control is transferred to the function specified by EntryPoint\r
+  using the new stack specified by NewStack and passing in the parameters\r
+  specified by Context1 and Context2. Context1 and Context2 are optional and\r
+  may be NULL. The function EntryPoint must never return.\r
+\r
+  There are a number of constraints that must be followed before calling this\r
+  function:\r
+  1)  Interrupts must be disabled.\r
+  2)  The caller must be in 32-bit paged mode.\r
+  3)  CR0, CR3, and CR4 must be compatible with 32-bit paged mode.\r
+  4)  CR3 must point to valid page tables that guarantee that the pages for\r
+      this function and the stack are identity mapped.\r
+\r
+  @param  EntryPoint  A pointer to function to call with the new stack after\r
+                      paging is disabled.\r
+  @param  Context1    A pointer to the context to pass into the EntryPoint\r
+                      function as the first parameter after paging is disabled.\r
+  @param  Context2    A pointer to the context to pass into the EntryPoint\r
+                      function as the second parameter after paging is\r
+                      disabled.\r
+  @param  NewStack    A pointer to the new stack to use for the EntryPoint\r
+                      function after paging is disabled.\r
+\r
+**/\r
 VOID\r
 EFIAPI\r
 InternalX86DisablePaging32 (\r
@@ -37,18 +101,8 @@ InternalX86DisablePaging32 (
   IN      VOID                      *NewStack\r
   )\r
 {\r
-  ASSERT (FALSE);\r
-}\r
-\r
-VOID\r
-EFIAPI\r
-InternalX86EnablePaging64 (\r
-  IN      UINT16                    Cs,\r
-  IN      UINT64                    EntryPoint,\r
-  IN      UINT64                    Context1,  OPTIONAL\r
-  IN      UINT64                    Context2,  OPTIONAL\r
-  IN      UINT64                    NewStack\r
-  )\r
-{\r
+  //\r
+  // This function cannot work on X64 platform\r
+  //\r
   ASSERT (FALSE);\r
 }\r