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-rw-r--r--com32/modules/Makefile2
-rw-r--r--com32/modules/ifcpu64.c126
2 files changed, 127 insertions, 1 deletions
diff --git a/com32/modules/Makefile b/com32/modules/Makefile
index dc114f57..6624a948 100644
--- a/com32/modules/Makefile
+++ b/com32/modules/Makefile
@@ -54,7 +54,7 @@ COM32DIR = $(AUXDIR)/com32
MODULES = chain.c32 ethersel.c32 mboot.c32 dmitest.c32 cpuidtest.c32 \
pcitest.c32 elf.c32 linux.c32 reboot.c32 pmload.c32 meminfo.c32 \
- sdi.c32 sanboot.c32
+ sdi.c32 sanboot.c32 ifcpu64.c32
TESTFILES =
diff --git a/com32/modules/ifcpu64.c b/com32/modules/ifcpu64.c
new file mode 100644
index 00000000..def43b35
--- /dev/null
+++ b/com32/modules/ifcpu64.c
@@ -0,0 +1,126 @@
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2008 H. Peter Anvin - All Rights Reserved
+ *
+ * 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, Inc., 51 Franklin St, Fifth Floor,
+ * Boston MA 02110-1301, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * ifcpu64.c
+ *
+ * Run one command if the CPU has 64-bit support, and another if it doesn't.
+ * Eventually this and other features should get folded into some kind
+ * of scripting engine.
+ *
+ * Usage:
+ *
+ * label boot_kernel
+ * kernel ifcpu64.c
+ * append boot_kernel_64 [-- boot_kernel_32pae] -- boot_kernel_32
+ * label boot_kernel_32
+ * kernel vmlinuz_32
+ * append ...
+ * label boot_kernel_64
+ * kernel vmlinuz_64
+ * append ...
+ */
+
+#include <alloca.h>
+#include <stdlib.h>
+#include <string.h>
+#include <cpuid.h>
+#include <syslinux/boot.h>
+
+static bool cpu_has_cpuid(void)
+{
+ return cpu_has_eflag(X86_EFLAGS_ID);
+}
+
+static bool cpu_has_level(uint32_t level)
+{
+ uint32_t group = level & 0xffff0000;
+ uint32_t limit = cpuid_eax(group);
+ if ((limit & 0xffff0000) != group)
+ return false;
+ if (level > limit)
+ return false;
+
+ return true;
+}
+
+static bool cpu_has_pae(void)
+{
+ if (!cpu_has_cpuid())
+ return false;
+
+ if (!cpu_has_level(0x00000001))
+ return false;
+
+ return !!(cpuid_edx(0x00000001) & (X86_FEATURE_PAE & 31));
+}
+
+static bool cpu_has_lm(void)
+{
+ if (!cpu_has_cpuid())
+ return false;
+
+ if (!cpu_has_level(0x80000001))
+ return false;
+
+ return !!(cpuid_edx(0x80000001) & (X86_FEATURE_LM & 31));
+}
+
+/* XXX: this really should be librarized */
+static void boot_args(char **args)
+{
+ int len = 0;
+ char **pp;
+ const char *p;
+ char c, *q, *str;
+
+ for (pp = args; *pp; pp++)
+ len += strlen(*pp);
+
+ q = str = alloca(len+1);
+ for (pp = args; *pp; pp++) {
+ p = *pp;
+ while ((c = *p++))
+ *q++ = c;
+ }
+ *q = '\0';
+
+ if (!str[0])
+ syslinux_run_default();
+ else
+ syslinux_run_command(str);
+}
+
+int main(int argc, char *argv[])
+{
+ char **args[3];
+ int i;
+ int n;
+
+ for (i = 0; i < 3; i++)
+ args[i] = &argv[1];
+
+ n = 1;
+ for (i = 1; i < argc; i++) {
+ if (!strcmp(argv[i], "--")) {
+ argv[i] = NULL;
+ args[n++] = &argv[i+1];
+ }
+ if (n >= 3)
+ break;
+ }
+
+ boot_args(cpu_has_lm() ? args[0] :
+ cpu_has_pae() ? args[1] :
+ args[2]);
+ return -1;
+}