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@@ -12,6 +12,8 @@
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#include "stdint.h"
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#include "stddef.h"
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#include "string.h"
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+#include "init.h"
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+#include "basemem.h"
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#include "librm.h"
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/*
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@@ -21,37 +23,14 @@
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/* Current location of librm in base memory */
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char *installed_librm = librm;
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+static uint32_t installed_librm_phys;
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-/*
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- * Install librm to base memory
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- *
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+/* Whether or not we have base memory currently allocated for librm.
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+ * Note that we *can* have a working librm present in unallocated base
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+ * memory; this is the situation at startup for all real-mode
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+ * prefixes.
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*/
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-void install_librm ( void *addr ) {
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- memcpy ( addr, librm, librm_size );
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- installed_librm = addr;
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-}
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-
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-/*
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- * Increment lock count of librm
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- *
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- */
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-void lock_librm ( void ) {
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- inst_librm_ref_count++;
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-}
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-
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-/*
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- * Decrement lock count of librm
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- *
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- */
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-void unlock_librm ( void ) {
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-#ifdef DEBUG_LIBRM
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- if ( inst_librm_ref_count == 0 ) {
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- printf ( "librm: ref count gone negative\n" );
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- lockup();
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- }
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-#endif
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- inst_librm_ref_count--;
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-}
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+static int allocated_librm = 0;
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/*
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* Allocate space on the real-mode stack and copy data there.
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@@ -84,4 +63,105 @@ void remove_from_rm_stack ( void *data, size_t size ) {
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inst_rm_stack.offset += size;
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};
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+/*
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+ * Install librm to base memory
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+ *
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+ */
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+static inline void install_librm ( char *addr ) {
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+ memcpy ( addr, librm, librm_size );
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+ installed_librm = addr;
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+}
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+
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+/*
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+ * Uninstall librm from base memory. This copies librm back to the
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+ * "master" copy, so that it can be reinstalled to a new location,
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+ * preserving the values for rm_ss and rm_sp from the old installed
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+ * copy.
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+ *
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+ */
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+static inline void uninstall_librm ( void ) {
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+ memcpy ( librm, installed_librm, librm_size );
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+}
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+
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+/*
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+ * On entry, record the physical location of librm. Do this so that
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+ * we can update installed_librm after relocation.
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+ *
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+ * Doing this is probably more efficient than making installed_librm
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+ * be a physical address, because of the number of times that
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+ * installed_librm gets referenced in the remainder of the code.
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+ *
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+ */
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+static void librm_init ( void ) {
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+ installed_librm_phys = virt_to_phys ( installed_librm );
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+}
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+
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+/*
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+ * On exit, we want to leave a copy of librm in *unallocated* base
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+ * memory. It must be there so that we can exit via a 16-bit exit
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+ * path, but it must not be allocated because nothing will ever
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+ * deallocate it once we exit.
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+ *
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+ */
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+static void librm_exit ( void ) {
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+ /* Free but do not zero the base memory */
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+ if ( allocated_librm ) {
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+ free_base_memory ( installed_librm, librm_size );
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+ allocated_librm = 0;
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+ }
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+}
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+
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+/*
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+ * On reset, we want to free up our old installed copy of librm, if
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+ * any, then allocate a new base memory block and install there.
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+ *
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+ */
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+
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+static void librm_reset ( void ) {
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+ char *new_librm;
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+
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+ /* Point installed_librm back at last known physical location */
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+ installed_librm = phys_to_virt ( installed_librm_phys );
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+
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+ /* Uninstall old librm */
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+ uninstall_librm();
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+
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+ /* Free allocated base memory, if applicable */
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+ librm_exit();
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+
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+ /* Allocate space for new librm */
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+ new_librm = alloc_base_memory ( librm_size );
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+ allocated_librm = 1;
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+
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+ /* Install new librm */
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+ install_librm ( new_librm );
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+}
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+
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+INIT_FN ( INIT_LIBRM, librm_init, librm_reset, librm_exit );
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+
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+
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+
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+
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+/*
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+ * Increment lock count of librm
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+ *
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+ */
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+void lock_librm ( void ) {
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+ inst_librm_ref_count++;
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+}
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+
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+/*
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+ * Decrement lock count of librm
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+ *
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+ */
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+void unlock_librm ( void ) {
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+#ifdef DEBUG_LIBRM
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+ if ( inst_librm_ref_count == 0 ) {
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+ printf ( "librm: ref count gone negative\n" );
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+ lockup();
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+ }
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+#endif
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+ inst_librm_ref_count--;
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+}
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+
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#endif /* KEEP_IT_REAL */
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