amd/agesa/f1?/Lib/amdlib.c: Integer overflow in loop construct

The semantics of this loop relies on an integer overflow in Index >=0
that implies a return value of (UINT8)-1 which around wraps to 0xFF, or
VOLT_UNSUPPORTED.

Change-Id: I44d68973d0a80093350b2a8a4d3b46bfbb57917a
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5801
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

5 files changed, 15 insertions, 15 deletions

diff --git a/src/vendorcode/amd/agesa/f10/Lib/amdlib.c b/src/vendorcode/amd/agesa/f10/Lib/amdlib.c
index d88eee7..83e6a00 100644
--- a/src/vendorcode/amd/agesa/f10/Lib/amdlib.c
+++ b/src/vendorcode/amd/agesa/f10/Lib/amdlib.c
@@ -344,11 +344,11 @@ LibAmdBitScanReverse (
   IN       UINT32 value
 )
 {
-  UINTN Index;
+  UINT8 Index;
   for (Index = 31; Index >= 0; Index--){
-      if (value & (1 << Index)) break;
+      if (value & (1 << Index)) return Index;
   }
-  return (UINT8) Index;
+  return 0xFF;
 }
 VOID
 LibAmdMsrRead (
diff --git a/src/vendorcode/amd/agesa/f12/Lib/amdlib.c b/src/vendorcode/amd/agesa/f12/Lib/amdlib.c
index cb8f695..f88eb98 100644
--- a/src/vendorcode/amd/agesa/f12/Lib/amdlib.c
+++ b/src/vendorcode/amd/agesa/f12/Lib/amdlib.c
@@ -348,11 +348,11 @@ LibAmdBitScanReverse (
   IN       UINT32 value
 )
 {
-  UINTN Index;
+  UINT8 Index;
   for (Index = 31; Index >= 0; Index--){
-      if (value & (1 << Index)) break;
+      if (value & (1 << Index)) return Index;
   }
-  return (UINT8) Index;
+  return 0xFF;
 }
 VOID
 LibAmdMsrRead (
diff --git a/src/vendorcode/amd/agesa/f14/Lib/amdlib.c b/src/vendorcode/amd/agesa/f14/Lib/amdlib.c
index 31b3f1e..c1fa494 100644
--- a/src/vendorcode/amd/agesa/f14/Lib/amdlib.c
+++ b/src/vendorcode/amd/agesa/f14/Lib/amdlib.c
@@ -348,11 +348,11 @@ LibAmdBitScanReverse (
   IN       UINT32 value
 )
 {
-  UINTN Index;
+  UINT8 Index;
   for (Index = 31; Index >= 0; Index--){
-      if (value & (1 << Index)) break;
+      if (value & (1 << Index)) return Index;
   }
-  return (UINT8) Index;
+  return 0xFF;
 }
 VOID
 LibAmdMsrRead (
diff --git a/src/vendorcode/amd/agesa/f15/Lib/amdlib.c b/src/vendorcode/amd/agesa/f15/Lib/amdlib.c
index e51a971..1180ad2 100644
--- a/src/vendorcode/amd/agesa/f15/Lib/amdlib.c
+++ b/src/vendorcode/amd/agesa/f15/Lib/amdlib.c
@@ -348,11 +348,11 @@ LibAmdBitScanReverse (
   IN       UINT32 value
 )
 {
-  UINTN Index;
+  UINT8 Index;
   for (Index = 31; Index >= 0; Index--){
-      if (value & (1 << Index)) break;
+      if (value & (1 << Index)) return Index;
   }
-  return (UINT8) Index;
+  return 0xFF;
 }
 
 UINT64
diff --git a/src/vendorcode/amd/agesa/f15tn/Lib/amdlib.c b/src/vendorcode/amd/agesa/f15tn/Lib/amdlib.c
index 55adc8a..9646e6d 100644
--- a/src/vendorcode/amd/agesa/f15tn/Lib/amdlib.c
+++ b/src/vendorcode/amd/agesa/f15tn/Lib/amdlib.c
@@ -359,11 +359,11 @@ LibAmdBitScanReverse (
   IN       UINT32 value
 )
 {
-  UINTN Index;
+  UINT8 Index;
   for (Index = 31; Index >= 0; Index--){
-      if (value & (1 << Index)) break;
+      if (value & (1 << Index)) return Index;
   }
-  return (UINT8) Index;
+  return 0xFF;
 }
 VOID
 LibAmdMsrRead (