New subject: [PATCH 2/2] Allow allocation of SMBIOS table in f-segment if it is small.

4 Aug 2011

If the SMBIOS is small (less than 600 bytes) allow it to be allocated
in the f-segment.  This works around a bug in JunOS - it crashes on
SMBIOS tables located in high memory.
---
 src/config.h |    2 ++
 src/smbios.c |   11 +++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/config.h b/src/config.h
index f2fce89..d182b13 100644
--- a/src/config.h
+++ b/src/config.h
@@ -51,6 +51,8 @@
 #define BUILD_SMM_ADDR            0xa8000
 #define BUILD_SMM_SIZE            0x8000
+#define BUILD_MAX_SMBIOS_FSEG     600
+
 // Important real-mode segments
 #define SEG_IVT      0x0000
 #define SEG_BDA      0x0040
diff --git a/src/smbios.c b/src/smbios.c
index 8df0f2d..7db8cce 100644
--- a/src/smbios.c
+++ b/src/smbios.c
@@ -17,7 +17,13 @@ smbios_entry_point_init(u16 max_structure_size,
                         u16 number_of_structures)
 {
     struct smbios_entry_point *ep = malloc_fseg(sizeof(*ep));
-    void *finaltable = malloc_high(structure_table_length);
+    void *finaltable;
+    if (structure_table_length <= BUILD_MAX_SMBIOS_FSEG)
+        // Table is small enough for f-seg - allocate there.  This
+        // works around a bug in JunOS (at least for small SMBIOS tables).
+        finaltable = malloc_fseg(structure_table_length);
+    else
+        finaltable = malloc_high(structure_table_length);
     if (!ep || !finaltable) {
         warn_noalloc();
         free(ep);
@@ -44,7 +50,8 @@ smbios_entry_point_init(u16 max_structure_size,
ep->intermediate_checksum -= checksum((void*)ep + 0x10, ep->length - 0x10);
-    dprintf(1, "SMBIOS ptr=%p table=%p\n", ep, finaltable);
+    dprintf(1, "SMBIOS ptr=%p table=%p size=%d\n"
+            , ep, finaltable, structure_table_length);
 }
#define load_str_field_with_default(type, field, def)                   \
-- 
1.7.4.4



    