PRD: cleaned BitString::Mask()

This function had a off-by-one error that could access memory beyond
the available memory space.

Change-Id: I32e547c7238e3307f189334638c6239ea6940e62
RTC: 167819
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/35690
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Reviewed-by: Benjamin J. Weisenbeck <bweisenb@us.ibm.com>
Reviewed-by: Caleb N. Palmer <cnpalmer@us.ibm.com>
Reviewed-by: Zane C. Shelley <zshelle@us.ibm.com>
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/36203
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>

5 files changed, 33 insertions, 99 deletions

diff --git a/src/usr/diag/prdf/common/framework/register/iipscr.C b/src/usr/diag/prdf/common/framework/register/iipscr.C
index 127992be5..bfc68ca33 100755
--- a/src/usr/diag/prdf/common/framework/register/iipscr.C
+++ b/src/usr/diag/prdf/common/framework/register/iipscr.C
@@ -120,7 +120,7 @@ uint32_t SCAN_COMM_REGISTER_CLASS::Read
   if(rc == SUCCESS)
   {
     BIT_STRING_CLASS & bitString = AccessBitString();
-    bitString.Mask(mask);
+    bitString.maskString(mask);
   }
 
   return(rc);
diff --git a/src/usr/diag/prdf/common/framework/register/prdfErrorRegisterMask.C b/src/usr/diag/prdf/common/framework/register/prdfErrorRegisterMask.C
index 64aa10009..0c083d03e 100755
--- a/src/usr/diag/prdf/common/framework/register/prdfErrorRegisterMask.C
+++ b/src/usr/diag/prdf/common/framework/register/prdfErrorRegisterMask.C
@@ -110,14 +110,14 @@ const BIT_STRING_CLASS & ErrorRegisterMask::Read()
   scr_rc = scr.Read();
   bitString = *scr.GetBitString();
   // apply software mask
-  bitString.Mask(bitStringMask);
+  bitString.maskString(bitStringMask);
   // apply hardware mask - if scan comm register for it was specified
   if(&xMaskScr != NULL)  /*constant condition*/        // dg00
   {                                                    // dg00
     int32_t rc = xMaskScr.Read();                       // dg00
     if(rc == SUCCESS)                                  // dg00
     {                                                  // dg00
-      bitString.Mask(*(xMaskScr.GetBitString()));      // dg00
+      bitString.maskString(*(xMaskScr.GetBitString()));      // dg00
     }                                                  // dg00
   }                                                    // dg00
 
diff --git a/src/usr/diag/prdf/common/util/prdfBitKey.C b/src/usr/diag/prdf/common/util/prdfBitKey.C
index beb527866..79f648572 100755
--- a/src/usr/diag/prdf/common/util/prdfBitKey.C
+++ b/src/usr/diag/prdf/common/util/prdfBitKey.C
@@ -326,7 +326,7 @@ void BitKey::removeBits(const BitKey & i_bk)
 {
   BitString mybs(iv_Capacity,(CPU_WORD *)DataPtr());
   const BitString yobs(i_bk.iv_Capacity,(CPU_WORD *)i_bk.cDataPtr());
-  mybs.Mask(yobs);
+  mybs.maskString(yobs);
 }
 
 //------------------------------------------------------------------------------
diff --git a/src/usr/diag/prdf/common/util/prdfBitString.C b/src/usr/diag/prdf/common/util/prdfBitString.C
index 7bc6ab7ee..324dca132 100755
--- a/src/usr/diag/prdf/common/util/prdfBitString.C
+++ b/src/usr/diag/prdf/common/util/prdfBitString.C
@@ -128,6 +128,24 @@ void BitString::setString( const BitString & i_sStr, uint32_t i_sPos,
 
 //------------------------------------------------------------------------------
 
+void BitString::maskString( const BitString & i_mask )
+{
+    // Get the length of the smallest string.
+    uint32_t actLen = std::min( getBitLen(), i_mask.getBitLen() );
+
+    for ( uint32_t pos = 0; pos < actLen; pos += CPU_WORD_BIT_LEN )
+    {
+        uint32_t len = std::min( actLen - pos, CPU_WORD_BIT_LEN );
+
+        CPU_WORD dVal =        GetField( pos, len );
+        CPU_WORD sVal = i_mask.GetField( pos, len );
+
+        SetField( pos, len, dVal & ~sVal );
+    }
+}
+
+//------------------------------------------------------------------------------
+
 uint32_t BitString::GetSetCount(uint32_t bit_position,
                                     uint32_t leng
                                     ) const
@@ -367,77 +385,6 @@ bool BitString::IsZero() const
     return true; // everything was zero
 }
 
-// Function Specification //////////////////////////////////////////
-//
-//  Title:  Mask
-//
-//  Purpose:  This function masks the bits in the string with the
-//            corresponding bits in the specified Bit String.  For
-//            each corresponding position, if the bit in the
-//            parameter Bit String is set(1), the bit in this string
-//            is cleared(0). If the length of the parameter string
-//            is greater than the length of this string, then the
-//            extra bits are ignored.  If the length of the
-//            parameter string are less than this the length of
-//            this string, then the extra bits in this string are
-//            not modified.
-//
-//  Side-effects:  Bit String may be modified.
-//
-//  Dependencies:  None.
-//
-//  Time Complexity:  O(m) where m is the length
-//
-//  Examples:  Parameter String:  1001
-//             Old String:       1100
-//             New String:       0100
-//
-//             Parameter String:  100111
-//             Old String:       1100
-//             New String:       0100
-//
-//             Parameter String:  1001
-//             Old String:       110001
-//             New String:       010001
-//
-// End Function Specification //////////////////////////////////////
-
-void BitString::Mask
-(
- const BitString & string
- )
-{
-  CPU_WORD value, string_value;
-  uint32_t current_offset;
-  uint32_t l;
-
-  /* Use smaller length                                               */
-  l = std::min(iv_bitLen, string.iv_bitLen);
-
-  current_offset = 0;
-  while(true)
-  {
-    if(l > CPU_WORD_BIT_LEN)
-    {
-      /* Set values using full CPU_WORDs                              */
-      value = GetField(current_offset, CPU_WORD_BIT_LEN);
-      string_value = string.GetField(current_offset, CPU_WORD_BIT_LEN);
-      SetField(current_offset, CPU_WORD_BIT_LEN,
-               value & (~string_value));
-      l -= CPU_WORD_BIT_LEN;
-      current_offset += CPU_WORD_BIT_LEN;
-    }
-    else
-    {
-      /* Set value in remainder of last CPU_WORD                      */
-      value = GetField(current_offset, l);
-      string_value = string.GetField(current_offset, l);
-      SetField(current_offset, l, value & (~string_value));
-      break;
-    }
-  }
-}
-
 //-------------------------------------------------------------------------------------------------
 
 CPU_WORD * BitString::GetRelativePosition(uint32_t & oBitOffset, uint32_t iBitPos) const
diff --git a/src/usr/diag/prdf/common/util/prdfBitString.H b/src/usr/diag/prdf/common/util/prdfBitString.H
index fe50ec130..a54477fff 100755
--- a/src/usr/diag/prdf/common/util/prdfBitString.H
+++ b/src/usr/diag/prdf/common/util/prdfBitString.H
@@ -228,6 +228,17 @@ class BitString
         setString( i_sStr, 0, i_sStr.getBitLen() );
     }
 
+    /**
+     * @brief Masks (clears) any bits set in this string that correspond to bits
+     *        set in the given string (this & ~mask).
+     * @param i_mask The mask string.
+     * @note  If the length of the given string is greater than the length of
+     *        this string, then the extra bits are ignored.
+     * @note  If the length of the given string is less than the length of this
+     *        string, then the extra bits in this string are not modified.
+     */
+    void maskString( const BitString & i_mask );
+
   /*!
    Comparison
    \remarks The bitstrings must be the same length and have the same bits set to be equal
@@ -335,30 +346,6 @@ class BitString
   bool IsZero(void) const;
 
   /*!
-   Mask off (Clear) bits positions in this string that are Set in the string provided
-   \param bitString containing the mask
-   \post Set bit positions in string provided are cleared in this string
-   \notes If the parameter string is longer than this string than extra bits are ignored.
-          If the parameter string is shorter than this string than extra bits in this string
-          are not modified.
-   \verbatim
-    Examples:  Parameter String:  1001
-               Old String:       1100
-               New String:       0100
-
-               Parameter String:  100111
-               Old String:       1100
-               New String:       0100
-
-               Parameter String:  1001
-               Old String:       110001
-               New String:       010001
-
-   \endverbatim
-   */
-  void Mask(const BitString & string);
-
-  /*!
    Utility to Right justify a "Left-justified" value
    \param iLen: length of bit field to justify
    \param iValue: the value to justify