[pcbios] Add facility for testing arbitrary E820 memory maps
authorMichael Brown <mcb30@etherboot.org>
Thu, 25 Sep 2008 02:34:26 +0000 (03:34 +0100)
committerMichael Brown <mcb30@etherboot.org>
Thu, 25 Sep 2008 02:34:26 +0000 (03:34 +0100)
We seem to be having issues with various E820 memory maps.  These
problems are often difficult to reproduce, requiring access to the
specific system exhibiting the problem.

Add a facility for hooking in a fake E820 map generator, using an
arbitrary map defined in a C array, solely in order to be able to test
the map-mangling code against arbitrary E820 maps.

src/arch/i386/firmware/pcbios/fakee820.c [new file with mode: 0644]
src/arch/i386/firmware/pcbios/hidemem.c
src/arch/i386/include/fakee820.h [new file with mode: 0644]

diff --git a/src/arch/i386/firmware/pcbios/fakee820.c b/src/arch/i386/firmware/pcbios/fakee820.c
new file mode 100644 (file)
index 0000000..e171edf
--- /dev/null
@@ -0,0 +1,90 @@
+/* Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <realmode.h>
+#include <biosint.h>
+
+/** Assembly routine in inline asm */
+extern void int15_fakee820();
+
+/** Original INT 15 handler */
+static struct segoff __text16 ( real_int15_vector );
+#define real_int15_vector __use_text16 ( real_int15_vector )
+
+/** An INT 15,e820 memory map entry */
+struct e820_entry {
+       /** Start of region */
+       uint64_t start;
+       /** Length of region */
+       uint64_t len;
+       /** Type of region */
+       uint32_t type;
+} __attribute__ (( packed ));
+
+#define E820_TYPE_RAM          1 /**< Normal memory */
+#define E820_TYPE_RSVD         2 /**< Reserved and unavailable */
+#define E820_TYPE_ACPI         3 /**< ACPI reclaim memory */
+#define E820_TYPE_NVS          4 /**< ACPI NVS memory */
+
+/** Fake e820 map */
+static struct e820_entry __text16_array ( e820map, [] ) __used = {
+       { 0x00000000ULL, ( 0x000a0000ULL - 0x00000000ULL ), E820_TYPE_RAM },
+       { 0x00100000ULL, ( 0xcfb50000ULL - 0x00100000ULL ), E820_TYPE_RAM },
+       { 0xcfb50000ULL, ( 0xcfb64000ULL - 0xcfb50000ULL ), E820_TYPE_RSVD },
+       { 0xcfb64000ULL, ( 0xcfb66000ULL - 0xcfb64000ULL ), E820_TYPE_RSVD },
+       { 0xcfb66000ULL, ( 0xcfb85c00ULL - 0xcfb66000ULL ), E820_TYPE_ACPI },
+       { 0xcfb85c00ULL, ( 0xd0000000ULL - 0xcfb85c00ULL ), E820_TYPE_RSVD },
+       { 0xe0000000ULL, ( 0xf0000000ULL - 0xe0000000ULL ), E820_TYPE_RSVD },
+       { 0xfe000000ULL, (0x100000000ULL - 0xfe000000ULL ), E820_TYPE_RSVD },
+       {0x100000000ULL, (0x230000000ULL -0x100000000ULL ), E820_TYPE_RAM },
+};
+#define e820map __use_text16 ( e820map )
+
+void fake_e820 ( void ) {
+       __asm__ __volatile__ (
+               TEXT16_CODE ( "\nint15_fakee820:\n\t"
+                             "pushfw\n\t"
+                             "cmpl $0xe820, %%eax\n\t"
+                             "jne 99f\n\t"
+                             "cmpl $0x534d4150, %%edx\n\t"
+                             "jne 99f\n\t"
+                             "pushaw\n\t"
+                             "leaw e820map(%%bx), %%si\n\t"
+                             "cs rep movsb\n\t"
+                             "popaw\n\t"
+                             "movl %%edx, %%eax\n\t"
+                             "addl $20, %%ebx\n\t"
+                             "cmpl %0, %%ebx\n\t"
+                             "jne 1f\n\t"
+                             "xorl %%ebx,%%ebx\n\t"
+                             "\n1:\n\t"
+                             "popfw\n\t"
+                             "clc\n\t"
+                             "lret $2\n\t"
+                             "\n99:\n\t"
+                             "popfw\n\t"
+                             "ljmp *%%cs:real_int15_vector\n\t" )
+               : : "i" ( sizeof ( e820map ) ) );
+
+       hook_bios_interrupt ( 0x15, ( unsigned int ) int15_fakee820,
+                             &real_int15_vector );
+}
+
+void unfake_e820 ( void ) {
+       unhook_bios_interrupt ( 0x15, ( unsigned int ) int15_fakee820,
+                               &real_int15_vector );
+}
index 202081b..c9df7bd 100644 (file)
 #include <realmode.h>
 #include <biosint.h>
 #include <basemem.h>
+#include <fakee820.h>
 #include <gpxe/init.h>
 #include <gpxe/memmap.h>
 #include <gpxe/hidemem.h>
 
+/** Set to true if you want to test a fake E820 map */
+#define FAKE_E820 0
+
 /** Alignment for hidden memory regions */
 #define ALIGN_HIDDEN 4096   /* 4kB page alignment should be enough */
 
@@ -135,6 +139,13 @@ static void hide_etherboot ( void ) {
        DBG ( "Hiding gPXE from system memory map\n" );
        get_memmap ( &memmap );
 
+       /* Hook in fake E820 map, if we're testing one */
+       if ( FAKE_E820 ) {
+               DBG ( "Hooking in fake E820 map\n" );
+               fake_e820();
+               get_memmap ( &memmap );
+       }
+
        /* Initialise the hidden regions */
        hide_basemem();
        hide_umalloc ( virt_to_phys ( _text ), virt_to_phys ( _text ) );
@@ -194,6 +205,10 @@ static void unhide_etherboot ( int flags __unused ) {
         */
        unhook_bios_interrupt ( 0x15, ( unsigned int ) int15,
                                &int15_vector );
+
+       /* Unhook fake E820 map, if used */
+       if ( FAKE_E820 )
+               unfake_e820();
 }
 
 /** Hide Etherboot startup function */
diff --git a/src/arch/i386/include/fakee820.h b/src/arch/i386/include/fakee820.h
new file mode 100644 (file)
index 0000000..f1fe8af
--- /dev/null
@@ -0,0 +1,7 @@
+#ifndef _FAKEE820_H
+#define _FAKEE820_H
+
+extern void fake_e820 ( void );
+extern void unfake_e820 ( void );
+
+#endif /* _FAKEE820_H */