Import a small ELF trampoline, in which the kernel is embedded, and that

is able to load the kernel into memory, symbol table included. This is
needed to be able to access the symbol table from DDB without a boot
loader.

2 files changed, 233 insertions, 0 deletions

diff --git a/sys/arm/arm/elf_trampoline.c b/sys/arm/arm/elf_trampoline.c
new file mode 100644
index 0000000..cfe17ba
--- /dev/null
+++ b/sys/arm/arm/elf_trampoline.c
@@ -0,0 +1,198 @@
+/*-
+ * Copyright (c) 2005 Olivier Houchard.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+#include <machine/asm.h>
+#include <sys/types.h>
+#include <sys/elf32.h>
+#include <sys/param.h>
+#include <machine/elf.h>
+#include <stdlib.h>
+
+#include "opt_global.h"
+
+extern char kernel_start[];
+extern char kernel_end[];
+
+static __inline void *
+memcpy(void *dst, const void *src, int len)
+{
+	const char *s = src;
+    	char *d = dst;
+	
+	while (len--) {
+		*d++ = *s++;
+	}
+	return (dst);
+}
+
+static __inline void
+bzero(char *addr, int count)
+{
+	while (count > 0) {
+		*addr = 0;
+		addr++;
+		count--;
+	}
+}
+
+void *
+load_kernel(unsigned int kstart, unsigned int kend, unsigned int curaddr,unsigned int func_end, int d)
+{
+	Elf32_Ehdr *eh;
+	Elf32_Phdr phdr[512] /* XXX */, *php;
+	Elf32_Shdr *shdr;
+	int i,j;
+	void *entry_point;
+	int symtabindex;
+	int symstrindex;
+	vm_offset_t lastaddr = 0;
+	Elf_Addr ssym, esym;
+	Elf_Dyn *dp;
+	
+	eh = (Elf32_Ehdr *)kstart;
+	ssym = esym = 0;
+	entry_point = (void*)eh->e_entry;
+	memcpy(phdr, (void *)(kstart + eh->e_phoff ),
+	    eh->e_phnum * sizeof(phdr[0]));
+	/* Determine lastaddr. */
+	for (i = 0; i < eh->e_phnum; i++) {
+		if (lastaddr < (phdr[i].p_vaddr - KERNVIRTADDR + curaddr
+		    + phdr[i].p_memsz))
+			lastaddr = phdr[i].p_vaddr - KERNVIRTADDR +
+			    curaddr + phdr[i].p_memsz;
+	}
+	
+	/* Now grab the symbol tables. */
+	lastaddr = roundup(lastaddr, sizeof(long));
+	if (eh->e_shnum * eh->e_shentsize != 0 &&
+	    eh->e_shoff != 0) {
+		symtabindex = symstrindex = -1;
+		shdr = (Elf_Shdr *)(kstart + eh->e_shoff);
+		for (i = 0; i < eh->e_shnum; i++) {
+			if (shdr[i].sh_type == SHT_SYMTAB) {
+				for (j = 0; j < eh->e_phnum; j++) {
+					if (phdr[j].p_type == PT_LOAD &&
+					    shdr[i].sh_offset >=
+					    phdr[j].p_offset &&
+					    (shdr[i].sh_offset + 
+					     shdr[i].sh_size <=
+					     phdr[j].p_offset +
+					     phdr[j].p_filesz)) {
+						shdr[i].sh_offset = 0;
+						shdr[i].sh_size = 0;
+						j = eh->e_phnum;
+					}
+				}
+				if (shdr[i].sh_offset != 0 && 
+				    shdr[i].sh_size != 0) {
+					symtabindex = i;
+					symstrindex = shdr[i].sh_link;
+				}
+			}
+		}
+		func_end = roundup(func_end, sizeof(long));
+		if (symtabindex >= 0 && symstrindex >= 0) {
+			ssym = lastaddr;
+			if (d) {
+				memcpy((void *)func_end, (void *)(
+				    shdr[symtabindex].sh_offset + kstart), 
+				    shdr[symtabindex].sh_size);
+				memcpy((void *)(func_end +
+				    shdr[symtabindex].sh_size),
+				    (void *)(shdr[symstrindex].sh_offset +
+				    kstart), shdr[symstrindex].sh_size);
+				*(Elf_Size *)lastaddr = 
+				    shdr[symtabindex].sh_size;
+			}
+			lastaddr += sizeof(shdr[symtabindex].sh_size);
+			if (d)
+				memcpy((void*)lastaddr,
+				    (void *)func_end,
+ 				    shdr[symtabindex].sh_size);
+			lastaddr += shdr[symtabindex].sh_size;
+			lastaddr = roundup(lastaddr,
+			    sizeof(shdr[symtabindex].sh_size));
+			if (d)
+				*(Elf_Size *)lastaddr =
+				    shdr[symstrindex].sh_size;
+			lastaddr += sizeof(shdr[symstrindex].sh_size);
+			if (d)
+				memcpy((void*)lastaddr,
+				    (void*)(func_end +
+					    shdr[symtabindex].sh_size),
+				    shdr[symstrindex].sh_size);
+			lastaddr += shdr[symstrindex].sh_size;
+			lastaddr = roundup(lastaddr, 
+			    sizeof(shdr[symstrindex].sh_size));
+			
+		}
+	}
+	if (!d)
+		return ((void *)lastaddr);
+	
+	j = eh->e_phnum;
+	for (i = 0; i < j; i++) {
+		volatile char c;
+		if (phdr[i].p_type != PT_LOAD) {
+			continue;
+		}
+		memcpy((void *)(phdr[i].p_vaddr - KERNVIRTADDR + curaddr),
+		    (void*)(kstart + phdr[i].p_offset), phdr[i].p_filesz);
+		/* Clean space from oversized segments, eg: bss. */
+		if (phdr[i].p_filesz < phdr[i].p_memsz)
+			bzero((void *)(phdr[i].p_vaddr - KERNVIRTADDR + 
+			    curaddr + phdr[i].p_filesz), phdr[i].p_memsz -
+			    phdr[i].p_filesz);
+	}
+	/* Now grab the symbol tables. */
+	*(Elf_Addr *)curaddr = ssym - curaddr + KERNVIRTADDR;
+	*((Elf_Addr *)curaddr + 1) = lastaddr - curaddr + KERNVIRTADDR;
+	/* Jump to the entry point. */
+	((void(*)(void))(entry_point - KERNVIRTADDR + curaddr))();
+	__asm __volatile(".globl func_end\n"
+	    "func_end:");
+	
+}
+
+extern char func_end[];
+
+int _start(void)
+{
+	void *curaddr;
+
+	__asm __volatile("mov %0, pc"  :
+	    "=r" (curaddr));
+	curaddr = (void*)((unsigned int)curaddr & 0xfff00000);
+	void *dst = 4 + load_kernel((unsigned int)&kernel_start, 
+	    (unsigned int)&kernel_end, (unsigned int)curaddr, 
+	    (unsigned int)&func_end, 0);
+	memcpy((void *)dst, (void *)&load_kernel, (unsigned int)&func_end - 
+	    (unsigned int)&load_kernel);
+	((void (*)())dst)((unsigned int)&kernel_start, 
+			  (unsigned int)&kernel_end, (unsigned int)curaddr,
+			  dst + (unsigned int)&func_end - 
+			  (unsigned int)(&load_kernel),1);
+}
diff --git a/sys/arm/arm/inckern.S b/sys/arm/arm/inckern.S
new file mode 100644
index 0000000..d47295b
--- /dev/null
+++ b/sys/arm/arm/inckern.S
@@ -0,0 +1,35 @@
+/*-
+ * Copyright (c) 2005 Olivier Houchard.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "opt_kernname.h"
+
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$")
+.section ".real_kernel","aw"
+.globl kernel_start;
+kernel_start:
+.incbin KERNNAME
+.globl kernel_end;
+kernel_end:
+.space 0x10000