MENU DEFAULT64 support for syslinux
On Mon, Jun 9, 2008 at 1:08 PM, Frans Pop <elendil@planet.nl> wrote:
> * Installer images for i386 and amd64 have a new boot menu using
> syslinux's vesamenu. This allows for a more user-friendly selection
> of for example the regular or graphical installer. For the multi-
> architecture CD/DVD images this change means the 64-bits version of
> the installer needs to be selected manually from the menu. See the
> Installation Guide [2] for details on how to use the new menu.
Beta 2 is looking nice, but not having multi-arch boot detection was a
bummer. So I took it upon myself to add the missing functionality to
menu.c32/vesamenu.c32. I'm posting the patch here first because I Am
Not A C Programmer(TM), and I really need more set of eyes on it.
Functionally it seems to be working well, as I converted my own
distro's[0] straight isolinux setup to a vesamenu system[1], and it's
been guessing correctly on everything I've thrown at it so far.
RF
[0] http://www.finnix.org/
[1] http://www.finnix.org/Image:Finnix_dev_boot_menu.png
diff -ruN syslinux-3.63+dfsg-orig/com32/menu/menu.h syslinux-3.63+dfsg/com32/menu/menu.h
--- syslinux-3.63+dfsg-orig/com32/menu/menu.h 2008-04-10 10:30:35.000000000 -0700
+++ syslinux-3.63+dfsg/com32/menu/menu.h 2008-06-10 00:48:38.424152595 -0700
@@ -163,6 +163,8 @@
struct color_table *color_table;
struct fkey_help fkeyhelp[12];
+
+ int has_default64;
};
extern struct menu *root_menu, *start_menu, *hide_menu, *menu_list;
diff -ruN syslinux-3.63+dfsg-orig/com32/menu/readconfig.c syslinux-3.63+dfsg/com32/menu/readconfig.c
--- syslinux-3.63+dfsg-orig/com32/menu/readconfig.c 2008-04-10 10:30:35.000000000 -0700
+++ syslinux-3.63+dfsg/com32/menu/readconfig.c 2008-06-10 01:01:58.937589284 -0700
@@ -66,6 +66,28 @@
NULL
};
+#define cpuid(func,ax,bx,cx,dx)\
+ __asm__ __volatile__ ("cpuid":\
+ "=a" (ax), "=b" (bx), "=c" (cx), "=d" (dx) : "a" (func));
+
+/*
+ * Determine if a CPU is x86_64 capable
+ */
+int is_64bit(void) {
+ unsigned int eax,ebx,ecx,edx;
+
+ cpuid(0x80000000,eax,ebx,ecx,edx);
+ /* if 0x80000001 is available, it's an AMD and/or x86_64 CPU */
+ if(eax >= 0x80000001) {
+ cpuid(0x80000001,eax,ebx,ecx,edx);
+ /* Bit 29 of 0x80000001_edx specifies x86_64 */
+ if((edx&(1<<29)) == (1<<29)) {
+ return 1;
+ }
+ }
+ return 0;
+}
+
/*
* Search the list of all menus for a specific label
*/
@@ -206,6 +228,7 @@
unsigned int ipappend;
unsigned int menuhide;
unsigned int menudefault;
+ unsigned int menudefault64;
unsigned int menuseparator;
unsigned int menudisabled;
unsigned int menuindent;
@@ -273,6 +296,8 @@
struct menu_entry *me;
const struct syslinux_ipappend_strings *ipappend;
+ int cpu_is_64bit = is_64bit();
+
if (!ld->label)
return; /* Nothing defined */
@@ -361,8 +386,26 @@
break;
}
- if ( ld->menudefault && me->action == MA_CMD )
+ /* If this ld has DEFAULT on it, it's a candidate for the default entry.
+ * But if a 64-bit default has already been set, we know that A) the CPU
+ * is 64-bit, and B) a DEFAULT64 has already occurred, so we don't even
+ * want to attempt 32-bit defaults anymore. If it's a 64-bit CPU,
+ * regular DEFAULTs can of course be considered for the default,
+ * but any past or future DEFAULT64 (with a corresponding 64-bit CPU)
+ * will eventually win.
+ */
+ if ( ld->menudefault && me->action == MA_CMD && !m->has_default64 )
m->defentry = m->nentries-1;
+
+ /* If the CPU is 64-bit and DEFAULT64 is set for this ld, set it as
+ * default. However, if DEFAULT64 is set and the CPU is NOT 64-bit,
+ * don't even consider it for a default.
+ */
+ if ( ld->menudefault64 && me->action == MA_CMD && cpu_is_64bit ) {
+ m->defentry = m->nentries-1;
+ m->has_default64 = 1;
+ }
+
}
clear_label_data(ld);
@@ -620,6 +663,8 @@
}
} else if ( looking_at(p, "default") ) {
ld.menudefault = 1;
+ } else if ( looking_at(p, "default64") ) {
+ ld.menudefault64 = 1;
} else if ( looking_at(p, "hide") ) {
ld.menuhide = 1;
} else if ( looking_at(p, "passwd") ) {
@@ -875,6 +920,7 @@
ld.ipappend = ipappend;
ld.menudefault = ld.menuhide = ld.menuseparator =
ld.menudisabled = ld.menuindent = 0;
+ ld.menudefault64 = 0;
} else if ( (ep = is_kernel_type(p, &type)) ) {
if ( ld.label ) {
refstr_put(ld.kernel);
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