Split bootsector execution code out into bootsector.c.
[gpxe.git] / src / arch / i386 / interface / pcbios / int13.c
index 8796f9a..b97d066 100644 (file)
@@ -26,6 +26,7 @@
 #include <realmode.h>
 #include <bios.h>
 #include <biosint.h>
+#include <bootsector.h>
 #include <int13.h>
 
 /** @file
@@ -44,23 +45,6 @@ static struct segoff __text16 ( int13_vector );
 /** Assembly wrapper */
 extern void int13_wrapper ( void );
 
-/** Vector for storing original INT 18 handler
- *
- * We do not chain to this vector, so there is no need to place it in
- * .text16.
- */
-static struct segoff int18_vector;
-
-/** Vector for storing original INT 19 handler
- *
- * We do not chain to this vector, so there is no need to place it in
- * .text16.
- */
-static struct segoff int19_vector;
-
-/** Restart point for INT 18 or 19 */
-extern void int13_exec_fail ( void );
-
 /** List of registered emulated drives */
 static LIST_HEAD ( drives );
 
@@ -114,6 +98,13 @@ static int int13_rw_sectors ( struct int13_drive *drive,
        unsigned int count;
        userptr_t buffer;
 
+       /* Validate blocksize */
+       if ( blockdev->blksize != INT13_BLKSIZE ) {
+               DBG ( "Invalid blocksize (%zd) for non-extended read/write\n",
+                     blockdev->blksize );
+               return -INT13_STATUS_INVALID;
+       }
+       
        /* Calculate parameters */
        cylinder = ( ( ( ix86->regs.cl & 0xc0 ) << 2 ) | ix86->regs.ch );
        assert ( cylinder < drive->cylinders );
@@ -129,13 +120,6 @@ static int int13_rw_sectors ( struct int13_drive *drive,
        DBG ( "C/H/S %d/%d/%d = LBA %#lx <-> %04x:%04x (count %d)\n", cylinder,
              head, sector, lba, ix86->segs.es, ix86->regs.bx, count );
 
-       /* Validate blocksize */
-       if ( blockdev->blksize != INT13_BLKSIZE ) {
-               DBG ( "Invalid blocksize (%zd) for non-extended read/write\n",
-                     blockdev->blksize );
-               return -INT13_STATUS_INVALID;
-       }
-       
        /* Read from / write to block device */
        if ( io ( blockdev, lba, count, buffer ) != 0 )
                return -INT13_STATUS_READ_ERROR;
@@ -333,6 +317,38 @@ static int int13_get_extended_parameters ( struct int13_drive *drive,
        return 0;
 }
 
+struct int13_cdrom_specification {
+       /** Size of packet in bytes */
+       uint8_t size;
+       /** Boot media type */
+       uint8_t media_type;
+       /** Drive number */
+       uint8_t drive;
+};
+
+/**
+ * INT 13, 4b - Get CD-ROM status / terminate emulation
+ *
+ * @v drive            Emulated drive
+ * @v ds:si            El Torito specification packet to fill in
+ * @ret status         Status code
+ */
+static int int13_cdrom_status_terminate ( struct int13_drive *drive,
+                                         struct i386_all_regs *ix86 ) {
+       struct int13_cdrom_specification specification;
+
+       DBG ( "Get CD-ROM emulation parameters to %04x:%04x\n",
+             ix86->segs.ds, ix86->regs.di );
+
+       memset ( &specification, 0, sizeof ( specification ) );
+       specification.size = sizeof ( specification );
+       specification.drive = drive->drive;
+
+       copy_to_real ( ix86->segs.ds, ix86->regs.si, &specification,
+                      sizeof ( specification ) );
+       return 0;
+}
+
 /**
  * INT 13 handler
  *
@@ -346,7 +362,7 @@ static void int13 ( struct i386_all_regs *ix86 ) {
                if ( drive->drive != ix86->regs.dl )
                        continue;
                
-               DBG ( "INT 13,%02x (%02x): ", command, drive->drive );
+               DBG ( "INT 13,%04x (%02x): ", ix86->regs.ax, drive->drive );
 
                switch ( command ) {
                case INT13_RESET:
@@ -379,6 +395,9 @@ static void int13 ( struct i386_all_regs *ix86 ) {
                case INT13_GET_EXTENDED_PARAMETERS:
                        status = int13_get_extended_parameters ( drive, ix86 );
                        break;
+               case INT13_CDROM_STATUS_TERMINATE:
+                       status = int13_cdrom_status_terminate ( drive, ix86 );
+                       break;
                default:
                        DBG ( "*** Unrecognised INT 13 ***\n" );
                        status = -INT13_STATUS_INVALID;
@@ -398,6 +417,8 @@ static void int13 ( struct i386_all_regs *ix86 ) {
 
                /* Set OF to indicate to wrapper not to chain this call */
                ix86->flags |= OF;
+
+               break;
        }
 }
 
@@ -453,6 +474,10 @@ static void guess_int13_geometry ( struct int13_drive *drive ) {
        unsigned long blocks_per_cyl;
        unsigned int i;
 
+       /* Don't even try when the blksize is invalid for C/H/S access */
+       if ( drive->blockdev->blksize != INT13_BLKSIZE )
+               return;
+
        /* Scan through partition table and modify guesses for heads
         * and sectors_per_track if we find any used partitions.
         */
@@ -564,6 +589,7 @@ void unregister_int13_drive ( struct int13_drive *drive ) {
 int int13_boot ( unsigned int drive ) {
        int status, signature;
        int discard_c, discard_d;
+       int rc;
 
        DBG ( "Booting from INT 13 drive %02x\n", drive );
 
@@ -593,48 +619,11 @@ int int13_boot ( unsigned int drive ) {
                return -ENOEXEC;
        }
 
-       /* Hook INTs 18 and 19 to capture failure paths */
-       hook_bios_interrupt ( 0x18, ( unsigned int ) int13_exec_fail,
-                             &int18_vector );
-       hook_bios_interrupt ( 0x19, ( unsigned int ) int13_exec_fail,
-                             &int19_vector );
-
-       /* Boot the loaded sector
-        *
-        * We assume that the boot sector may completely destroy our
-        * real-mode stack, so we preserve everything we need in
-        * static storage.
-        */
-       __asm__ __volatile__ ( REAL_CODE ( /* Save return address off-stack */
-                                          "popw %%cs:int13_saved_retaddr\n\t"
-                                          /* Save stack pointer */
-                                          "movw %%ss, %%ax\n\t"
-                                          "movw %%ax, %%cs:int13_saved_ss\n\t"
-                                          "movw %%sp, %%cs:int13_saved_sp\n\t"
-                                          /* Jump to boot sector */
-                                          "ljmp $0, $0x7c00\n\t"
-                                          /* Preserved variables */
-                                          "\nint13_saved_ss: .word 0\n\t"
-                                          "\nint13_saved_sp: .word 0\n\t"
-                                          "\nint13_saved_retaddr: .word 0\n\t"
-                                          /* Boot failure return point */
-                                          "\nint13_exec_fail:\n\t"
-                                          /* Restore stack pointer */
-                                          "movw %%cs:int13_saved_ss, %%ax\n\t"
-                                          "movw %%ax, %%ss\n\t"
-                                          "movw %%cs:int13_saved_sp, %%sp\n\t"
-                                          /* Return via saved address */
-                                          "jmp *%%cs:int13_saved_retaddr\n\t")
-                              : "=d" ( discard_d ) : "d" ( drive )
-                              : "eax", "ebx", "ecx", "esi", "edi", "ebp" );
-
-       DBG ( "Booted disk returned via INT 18 or 19\n" );
-
-       /* Unhook INTs 18 and 19 */
-       unhook_bios_interrupt ( 0x18, ( unsigned int ) int13_exec_fail,
-                               &int18_vector );
-       unhook_bios_interrupt ( 0x19, ( unsigned int ) int13_exec_fail,
-                               &int19_vector );
-       
-       return -ECANCELED;
+       /* Jump to boot sector */
+       if ( ( rc = call_bootsector ( 0x0, 0x7c00, drive ) ) != 0 ) {
+               DBG ( "INT 13 drive %02x boot returned\n", drive );
+               return rc;
+       }
+
+       return -ECANCELED; /* -EIMPOSSIBLE */
 }