From ce4210d673a2afd61732fb58a9df4b037b157f1a Mon Sep 17 00:00:00 2001
From: Olivier Houchard <cognet@FreeBSD.org>
Date: Thu, 24 Nov 2005 02:27:55 +0000
Subject: [PATCH] Use a magic number to know we were started from the elf
 wrapper. Add a dummy _start function to make the non-elf version of the
 wrapper work.

---
 sys/arm/arm/elf_trampoline.c            | 18 ++++++++++++++----
 sys/arm/include/elf.h                   |  5 +++++
 sys/arm/xscale/i80321/iq31244_machdep.c | 10 +++++-----
 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/sys/arm/arm/elf_trampoline.c b/sys/arm/arm/elf_trampoline.c
index cfe17bab005..aad5d854fe1 100644
--- a/sys/arm/arm/elf_trampoline.c
+++ b/sys/arm/arm/elf_trampoline.c
@@ -36,6 +36,14 @@ __FBSDID("$FreeBSD$");
 extern char kernel_start[];
 extern char kernel_end[];
 
+void __start(void);
+
+void
+_start(void)
+{
+	__start();
+}
+
 static __inline void *
 memcpy(void *dst, const void *src, int len)
 {
@@ -168,8 +176,10 @@ load_kernel(unsigned int kstart, unsigned int kend, unsigned int curaddr,unsigne
 			    phdr[i].p_filesz);
 	}
 	/* Now grab the symbol tables. */
-	*(Elf_Addr *)curaddr = ssym - curaddr + KERNVIRTADDR;
-	*((Elf_Addr *)curaddr + 1) = lastaddr - curaddr + KERNVIRTADDR;
+	*(Elf_Addr *)curaddr = MAGIC_TRAMP_NUMBER;
+	*((Elf_Addr *)curaddr + 1) = ssym - curaddr + KERNVIRTADDR;
+	*((Elf_Addr *)curaddr + 2) = lastaddr - curaddr + KERNVIRTADDR;
+
 	/* Jump to the entry point. */
 	((void(*)(void))(entry_point - KERNVIRTADDR + curaddr))();
 	__asm __volatile(".globl func_end\n"
@@ -179,7 +189,7 @@ load_kernel(unsigned int kstart, unsigned int kend, unsigned int curaddr,unsigne
 
 extern char func_end[];
 
-int _start(void)
+void __start(void)
 {
 	void *curaddr;
 
@@ -194,5 +204,5 @@ int _start(void)
 	((void (*)())dst)((unsigned int)&kernel_start, 
 			  (unsigned int)&kernel_end, (unsigned int)curaddr,
 			  dst + (unsigned int)&func_end - 
-			  (unsigned int)(&load_kernel),1);
+			  (unsigned int)(&load_kernel), 1);
 }
diff --git a/sys/arm/include/elf.h b/sys/arm/include/elf.h
index a6f1462fb3b..81351e8e91b 100644
--- a/sys/arm/include/elf.h
+++ b/sys/arm/include/elf.h
@@ -125,4 +125,9 @@ __ElfType(Auxinfo);
 #define	ELF_TARG_MACH	EM_ARM
 #define	ELF_TARG_VER	1
 
+/* 
+ * Magic number for the elf trampoline, chosen wisely to be an immediate 
+ * value.
+ */
+#define MAGIC_TRAMP_NUMBER	0x5c000003
 #endif /* !_MACHINE_ELF_H_ */
diff --git a/sys/arm/xscale/i80321/iq31244_machdep.c b/sys/arm/xscale/i80321/iq31244_machdep.c
index a49a3f71ee0..990b5b648cd 100644
--- a/sys/arm/xscale/i80321/iq31244_machdep.c
+++ b/sys/arm/xscale/i80321/iq31244_machdep.c
@@ -233,16 +233,16 @@ initarm(void *arg, void *arg2)
 	fake_preload[i++] = sizeof(uint32_t);
 	fake_preload[i++] = (uint32_t)&end - KERNBASE - 0x00200000;
 #ifdef DDB
-	if (*(uint32_t *)KERNVIRTADDR != 0) {
+	if (*(uint32_t *)KERNVIRTADDR == MAGIC_TRAMP_NUMBER) {
 		fake_preload[i++] = MODINFO_METADATA|MODINFOMD_SSYM;
 		fake_preload[i++] = sizeof(vm_offset_t);
-		fake_preload[i++] = *(uint32_t *)KERNVIRTADDR;
+		fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 4);
 		fake_preload[i++] = MODINFO_METADATA|MODINFOMD_ESYM;
 		fake_preload[i++] = sizeof(vm_offset_t);
-		fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 4);
-		lastaddr = *(uint32_t *)(KERNVIRTADDR + 4);
+		fake_preload[i++] = *(uint32_t *)(KERNVIRTADDR + 8);
+		lastaddr = *(uint32_t *)(KERNVIRTADDR + 8);
 		zend = lastaddr;
-		zstart = *(uint32_t *)KERNVIRTADDR;
+		zstart = *(uint32_t *)(KERNVIRTADDR + 4);
 		ksym_start = zstart;
 		ksym_end = zend;
 	} else