pxe: use bios_fbm() and real_base_mem to calculate free space

We don't need to individually add the PXE regions, we already have two
symbols that denote the memory region that will be freed when calling
unload_pxe().

This essentially reverts commit 03dda0f1 ("pxe: mark all PXE regions as
SMT_TERMINAL").

Signed-off-by: Matt Fleming <matt.fleming@intel.com>

1 files changed, 7 insertions, 47 deletions

diff --git a/core/fs/pxe/bios.c b/core/fs/pxe/bios.c
index c0102b31..c16b7c08 100644
--- a/core/fs/pxe/bios.c
+++ b/core/fs/pxe/bios.c
@@ -11,13 +11,6 @@ static uint16_t real_base_mem;	   /* Amount of DOS memory after freeing */
 static bool has_gpxe;
 static uint32_t gpxe_funcs;
 
-struct pxe_region {
-    addr_t start;
-    addr_t size;
-};
-
-static struct pxe_region __pxe_regions[PXE_Seg_BC_CodeWrite + 1];
-
 /*
  * Validity check on possible !PXE structure in buf
  * return 1 for success, 0 for failure.
@@ -98,8 +91,8 @@ static const struct pxenv_t *memory_scan_for_pxenv_struct(void)
 
 static int pxelinux_scan_memory(scan_memory_callback_t callback, void *data)
 {
-    addr_t start, end, size;
-    int i, rv = 0;
+    addr_t start, size;
+    int rv = 0;
 
     if (KeepPXE)
 	return 0;
@@ -110,46 +103,15 @@ static int pxelinux_scan_memory(scan_memory_callback_t callback, void *data)
      * that region as SMT_TERMINAL to indicate that the region will
      * become free at some point in the future.
      */
-    for (i = PXE_Seg_Stack; i <= PXE_Seg_BC_CodeWrite; i++) {
-	start = __pxe_regions[i].start;
-	size = __pxe_regions[i].size;
-	end = start + size;
-
-	if (!start || !size)
-	    continue;
-
-	dprintf("Marking PXE region (%d) 0x%x - 0x%x as SMT_TERMINAL\n",
-		i, start, end);
-	rv = callback(data, start, size, SMT_TERMINAL);
-    }
+    start = bios_fbm() << 10;
+    size = (real_base_mem - bios_fbm()) << 10;
+    dprintf("Marking PXE region 0x%x - 0x%x as SMT_TERMINAL\n",
+	start, start + size);
 
+    callback(data, start, size, SMT_TERMINAL);
     return rv;
 }
 
-static void setup_pxenv_regions(const struct pxenv_t *pxenv)
-{
-    __pxe_regions[PXE_Seg_Stack].start = pxenv->stackseg << 4;
-    __pxe_regions[PXE_Seg_Stack].size = pxenv->stacksize;
-    __pxe_regions[PXE_Seg_UNDIData].start = pxenv->undidataseg << 4;
-    __pxe_regions[PXE_Seg_UNDIData].size = pxenv->undidatasize;
-    __pxe_regions[PXE_Seg_UNDICode].start = pxenv->undicodeseg << 4;
-    __pxe_regions[PXE_Seg_UNDICode].size = pxenv->undicodesize;
-    __pxe_regions[PXE_Seg_BC_Data].start = pxenv->bc_dataseg << 4;
-    __pxe_regions[PXE_Seg_BC_Data].size = pxenv->bc_datasize;
-    __pxe_regions[PXE_Seg_BC_Code].start = pxenv->bc_codeseg << 4;
-    __pxe_regions[PXE_Seg_BC_Code].size = pxenv->bc_codesize;
-}
-
-static void setup_pxe_regions(const pxe_segdesc_t *seg)
-{
-    int i;
-
-    for (i = PXE_Seg_Stack; i <= PXE_Seg_BC_CodeWrite; i++) {
-	__pxe_regions[i].start = seg[i].sel << 4;
-	__pxe_regions[i].size = seg[i].size;
-    }
-}
-
 /*
  * Find the !PXE structure; we search for the following, in order:
  *
@@ -249,7 +211,6 @@ int pxe_init(bool quiet)
     PXEEntry = pxenv->rmentry;
     type = "PXENV+";
 
-    setup_pxenv_regions(pxenv);
     goto have_entrypoint;
 
  have_pxe:
@@ -260,7 +221,6 @@ int pxe_init(bool quiet)
     PXEEntry = pxe->entrypointsp;
     type = "!PXE";
 
-    setup_pxe_regions(pxe->seg);
  have_entrypoint:
     if (!quiet) {
 	printf("%s entry point found (we hope) at %04X:%04X via plan %c\n",