From 2c9ec833e39d1a4f8646ae17b915a3124283f300 Mon Sep 17 00:00:00 2001
From: Muhammad Rais Fathin Mudzakir <raisfathin@google.com>
Date: Wed, 22 Jun 2016 12:58:37 +1000
Subject: [PATCH 1/2] Refactor and fix a bug in find_RSDP method in HAL

Fixes a bug where if one RSDP finding method fails it does not
attempt to use the others
---
 source/tool/chipsec/hal/acpi.py | 111 +++++++++++++++++++-------------
 1 file changed, 68 insertions(+), 43 deletions(-)

diff --git a/source/tool/chipsec/hal/acpi.py b/source/tool/chipsec/hal/acpi.py
index b96b5b55..6921b9c6 100644
--- a/source/tool/chipsec/hal/acpi.py
+++ b/source/tool/chipsec/hal/acpi.py
@@ -221,16 +221,13 @@ class ACPI:
             rsdp_buf = self.cs.mem.read_physical_mem( rsdp_pa, ACPI_RSDP_EXT_SIZE)
             rsdp = RSDP(rsdp_buf)
         return rsdp
-
+
     #
-    # Searches for Root System Description Pointer (RSDP) in various locations for legacy/EFI systems
+    # Check RSDP in Extended BIOS Data Area
     #
-    def find_RSDP( self ):
-        rsdp_pa  = None
-        rsdp     = None
-        #
-        # Check RSDP in Extended BIOS Data Area first
-        #
+    def _find_RSDP_in_EBDA(self):
+        rsdp_pa = None
+        rsdp    = None
         if logger().HAL: logger().log( "[acpi] searching RSDP in EBDA.." )
         ebda_ptr_addr = 0x40E
         ebda_addr = struct.unpack('<H', self.cs.mem.read_physical_mem( ebda_ptr_addr, 2 ))[0] << 4
@@ -244,43 +241,54 @@ class ACPI:
                     logger().log( "[acpi] found RSDP in EBDA at: 0x%016X" % rsdp_pa )
                 else:
                     rsdp_pa = None
-        else:
-            #
-            # Search RSDP in legacy BIOS E/F segments (0xE0000 - 0xFFFFF)
-            #
-            membuf = self.cs.mem.read_physical_mem( 0xE0000, 0x20000 )
-            pos = membuf.find( ACPI_RSDP_SIG )
-            if -1 != pos:
-                rsdp_pa  = 0xE0000 + pos
-                rsdp     = self.read_RSDP(rsdp_pa)
-                if rsdp.is_RSDP_valid():
-                    logger().log( "[acpi] found RSDP in BIOS E/F segments: 0x%016X" % rsdp_pa )
-                else:
-                    rsdp_pa = None
+        return rsdp, rsdp_pa
+
+    #
+    # Search RSDP in legacy BIOS E/F segments (0xE0000 - 0xFFFFF)
+    #
+    def _find_RSDP_in_legacy_BIOS_segments(self):
+        rsdp_pa = None
+        rsdp    = None
+        membuf = self.cs.mem.read_physical_mem( 0xE0000, 0x20000 )
+        pos = membuf.find( ACPI_RSDP_SIG )
+        if -1 != pos:
+            rsdp_pa  = 0xE0000 + pos
+            rsdp     = self.read_RSDP(rsdp_pa)
+            if rsdp.is_RSDP_valid():
+                logger().log( "[acpi] found RSDP in BIOS E/F segments: 0x%016X" % rsdp_pa )
             else:
-                #
-                # Search for RSDP in the EFI memory (EFI Configuration Table)
-                #
-                if logger().HAL: logger().log( '[acpi] searching RSDP pointers in EFI Configuration Table..' )
-                (isFound,ect_pa,ect,ect_buf) = self.uefi.find_EFI_Configuration_Table()
-                if isFound:
-                    if RSDP_GUID_ACPI2_0 in ect.VendorTables:
-                        rsdp_pa = ect.VendorTables[ RSDP_GUID_ACPI2_0 ]
-                        logger().log( '[acpi] ACPI 2.0+ RSDP {%s} in EFI Config Table: 0x%016X' % (RSDP_GUID_ACPI2_0,rsdp_pa) )
-                    elif RSDP_GUID_ACPI1_0 in ect.VendorTables:
-                        rsdp_pa = ect.VendorTables[ RSDP_GUID_ACPI1_0 ]
-                        logger().log( '[acpi] ACPI 1.0 RSDP {%s} in EFI Config Table: 0x%016X' % (RSDP_GUID_ACPI1_0,rsdp_pa) )
-
-                    rsdp     = self.read_RSDP(rsdp_pa)
-                    if rsdp.is_RSDP_valid():
-                        logger().log( "[acpi] found RSDP in EFI Config Table: 0x%016X" % rsdp_pa )
-                    else:
-                        rsdp_pa = None
-
-        if rsdp_pa is not None and rsdp is not None:
-            logger().log( rsdp )
-            return (rsdp_pa, rsdp)
+                rsdp_pa = None
+        return rsdp, rsdp_pa
+
+    #
+    # Search for RSDP in the EFI memory (EFI Configuration Table)
+    #
+    def _find_RSDP_in_EFI_config_table(self):
+        rsdp_pa = None
+        rsdp    = None
+        if logger().HAL: logger().log( '[acpi] searching RSDP pointers in EFI Configuration Table..' )
+        (isFound,ect_pa,ect,ect_buf) = self.uefi.find_EFI_Configuration_Table()
+        if isFound:
+            if RSDP_GUID_ACPI2_0 in ect.VendorTables:
+                rsdp_pa = ect.VendorTables[ RSDP_GUID_ACPI2_0 ]
+                logger().log( '[acpi] ACPI 2.0+ RSDP {%s} in EFI Config Table: 0x%016X' % (RSDP_GUID_ACPI2_0,rsdp_pa) )
+            elif RSDP_GUID_ACPI1_0 in ect.VendorTables:
+                rsdp_pa = ect.VendorTables[ RSDP_GUID_ACPI1_0 ]
+                logger().log( '[acpi] ACPI 1.0 RSDP {%s} in EFI Config Table: 0x%016X' % (RSDP_GUID_ACPI1_0,rsdp_pa) )
 
+            rsdp     = self.read_RSDP(rsdp_pa)
+            if rsdp.is_RSDP_valid():
+                logger().log( "[acpi] found RSDP in EFI Config Table: 0x%016X" % rsdp_pa )
+            else:
+                rsdp_pa = None
+        return rsdp, rsdp_pa
+
+    #
+    # Search for RSDP in all EFI memory
+    #
+    def _find_RSDP_in_EFI(self):
+        rsdp_pa = None
+        rsdp    = None
         if logger().HAL: logger().log( "[acpi] searching all EFI memory for RSDP (this may take a minute).." )
         CHUNK_SZ = 1024*1024 # 1MB
         (smram_base, smram_limit, smram_size) = self.cs.cpu.get_SMRAM()
@@ -296,9 +304,26 @@ class ACPI:
                     logger().log( "[acpi] found RSDP in EFI memory: 0x%016X" % rsdp_pa )
                     break
             pa -= CHUNK_SZ
+        return rsdp, rsdp_pa
 
+    #
+    # Searches for Root System Description Pointer (RSDP) in various locations for legacy/EFI systems
+    #
+    def find_RSDP( self ):
+        rsdp, rsdp_pa = self._find_RSDP_in_EBDA()
+
+        if rsdp_pa is None:
+            rsdp, rsdp_pa = self._find_RSDP_in_legacy_BIOS_segments()
+
+        if rsdp_pa is None:
+            rsdp, rsdp_pa = self._find_RSDP_in_EFI_config_table()
+
+        if rsdp_pa is None:
+            rsdp, rsdp_pa = self._find_RSDP_in_EFI()
+
         if rsdp_pa is not None: logger().log( rsdp )
         return (rsdp_pa, rsdp)
+
     #
     # Retrieves System Description Table (RSDT or XSDT) either from RSDP or using OS API
     #

From de2df1a579eef69bb2c2b63d8b87525c0170fe6f Mon Sep 17 00:00:00 2001
From: Muhammad Rais Fathin Mudzakir <raisfathin@google.com>
Date: Wed, 22 Jun 2016 14:44:20 +1000
Subject: [PATCH 2/2] Update tests to test for known bug in "find_RSDP"

---
 source/tool/tests/software/test_util.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/source/tool/tests/software/test_util.py b/source/tool/tests/software/test_util.py
index 22b444e1..ea4f2936 100644
--- a/source/tool/tests/software/test_util.py
+++ b/source/tool/tests/software/test_util.py
@@ -120,8 +120,14 @@ class TestChipsecUtil(unittest.TestCase):
                                "CRRV" +                  # Creator Revision
                                struct.pack("<I", 0x300)) # Address of table
 
+            EBDA_ADDRESS = 0x99000
+
             def read_phys_mem(self, pa_hi, pa_lo, length):
-                if pa_lo == 0xE0000:
+                if pa_lo == 0x40E:
+                    return struct.pack("<H", self.EBDA_ADDRESS >> 4)
+                elif pa_lo >= self.EBDA_ADDRESS and pa_lo < 0xA0000:
+                    return "\xFF" * length
+                elif pa_lo == 0xE0000:
                     return self.RSDP_DESCRIPTOR[:length]
                 elif pa_lo == 0x200:
                     return self.RSDT_DESCRIPTOR[:length]