lib: elf: Move the generic elf loading/validating functions to lib

Move the generic elf loading/validating functions to lib/
so that they can be re-used and accessed by code existing
outside cmd.

While at it remove the duplicate static version of load_elf_image_phdr
under arch/arm/mach-imx/imx_bootaux.c.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Suggested-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

7 files changed, 258 insertions, 293 deletions

diff --git a/arch/arm/mach-imx/imx_bootaux.c b/arch/arm/mach-imx/imx_bootaux.c
index 21e96f8..ec0da11 100644
--- a/arch/arm/mach-imx/imx_bootaux.c
+++ b/arch/arm/mach-imx/imx_bootaux.c
@@ -12,70 +12,6 @@
 #include <linux/compiler.h>
 #include <cpu_func.h>
 
-#ifndef CONFIG_IMX8M
-const __weak struct rproc_att hostmap[] = { };
-
-static const struct rproc_att *get_host_mapping(unsigned long auxcore)
-{
-	const struct rproc_att *mmap = hostmap;
-
-	while (mmap && mmap->size) {
-		if (mmap->da <= auxcore &&
-		    mmap->da + mmap->size > auxcore)
-			return mmap;
-		mmap++;
-	}
-
-	return NULL;
-}
-
-/*
- * A very simple elf loader, assumes the image is valid, returns the
- * entry point address.
- */
-static unsigned long load_elf_image_phdr(unsigned long addr)
-{
-	Elf32_Ehdr *ehdr; /* ELF header structure pointer */
-	Elf32_Phdr *phdr; /* Program header structure pointer */
-	int i;
-
-	ehdr = (Elf32_Ehdr *)addr;
-	phdr = (Elf32_Phdr *)(addr + ehdr->e_phoff);
-
-	/* Load each program header */
-	for (i = 0; i < ehdr->e_phnum; ++i, ++phdr) {
-		const struct rproc_att *mmap = get_host_mapping(phdr->p_paddr);
-		void *dst, *src;
-
-		if (phdr->p_type != PT_LOAD)
-			continue;
-
-		if (!mmap) {
-			printf("Invalid aux core address: %08x",
-			       phdr->p_paddr);
-			return 0;
-		}
-
-		dst = (void *)(phdr->p_paddr - mmap->da) + mmap->sa;
-		src = (void *)addr + phdr->p_offset;
-
-		debug("Loading phdr %i to 0x%p (%i bytes)\n",
-		      i, dst, phdr->p_filesz);
-
-		if (phdr->p_filesz)
-			memcpy(dst, src, phdr->p_filesz);
-		if (phdr->p_filesz != phdr->p_memsz)
-			memset(dst + phdr->p_filesz, 0x00,
-			       phdr->p_memsz - phdr->p_filesz);
-		flush_cache((unsigned long)dst &
-			    ~(CONFIG_SYS_CACHELINE_SIZE - 1),
-			    ALIGN(phdr->p_filesz, CONFIG_SYS_CACHELINE_SIZE));
-	}
-
-	return ehdr->e_entry;
-}
-#endif
-
 int arch_auxiliary_core_up(u32 core_id, ulong addr)
 {
 	ulong stack, pc;
diff --git a/cmd/Kconfig b/cmd/Kconfig
index 6403bc4..faa133d 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -399,6 +399,7 @@ config CMD_ABOOTIMG
 config CMD_ELF
 	bool "bootelf, bootvx"
 	default y
+	select LIB_ELF
 	help
 	  Boot an ELF/vxWorks image from the memory.
 
diff --git a/cmd/elf.c b/cmd/elf.c
index 036be5f..10e8264 100644
--- a/cmd/elf.c
+++ b/cmd/elf.c
@@ -18,211 +18,6 @@
 #include <linux/linkage.h>
 #endif
 
-/*
- * A very simple ELF64 loader, assumes the image is valid, returns the
- * entry point address.
- *
- * Note if U-Boot is 32-bit, the loader assumes the to segment's
- * physical address and size is within the lower 32-bit address space.
- */
-static unsigned long load_elf64_image_phdr(unsigned long addr)
-{
-	Elf64_Ehdr *ehdr; /* Elf header structure pointer */
-	Elf64_Phdr *phdr; /* Program header structure pointer */
-	int i;
-
-	ehdr = (Elf64_Ehdr *)addr;
-	phdr = (Elf64_Phdr *)(addr + (ulong)ehdr->e_phoff);
-
-	/* Load each program header */
-	for (i = 0; i < ehdr->e_phnum; ++i) {
-		void *dst = (void *)(ulong)phdr->p_paddr;
-		void *src = (void *)addr + phdr->p_offset;
-
-		debug("Loading phdr %i to 0x%p (%lu bytes)\n",
-		      i, dst, (ulong)phdr->p_filesz);
-		if (phdr->p_filesz)
-			memcpy(dst, src, phdr->p_filesz);
-		if (phdr->p_filesz != phdr->p_memsz)
-			memset(dst + phdr->p_filesz, 0x00,
-			       phdr->p_memsz - phdr->p_filesz);
-		flush_cache(rounddown((unsigned long)dst, ARCH_DMA_MINALIGN),
-			    roundup(phdr->p_memsz, ARCH_DMA_MINALIGN));
-		++phdr;
-	}
-
-	if (ehdr->e_machine == EM_PPC64 && (ehdr->e_flags &
-					    EF_PPC64_ELFV1_ABI)) {
-		/*
-		 * For the 64-bit PowerPC ELF V1 ABI, e_entry is a function
-		 * descriptor pointer with the first double word being the
-		 * address of the entry point of the function.
-		 */
-		uintptr_t addr = ehdr->e_entry;
-
-		return *(Elf64_Addr *)addr;
-	}
-
-	return ehdr->e_entry;
-}
-
-static unsigned long load_elf64_image_shdr(unsigned long addr)
-{
-	Elf64_Ehdr *ehdr; /* Elf header structure pointer */
-	Elf64_Shdr *shdr; /* Section header structure pointer */
-	unsigned char *strtab = 0; /* String table pointer */
-	unsigned char *image; /* Binary image pointer */
-	int i; /* Loop counter */
-
-	ehdr = (Elf64_Ehdr *)addr;
-
-	/* Find the section header string table for output info */
-	shdr = (Elf64_Shdr *)(addr + (ulong)ehdr->e_shoff +
-			     (ehdr->e_shstrndx * sizeof(Elf64_Shdr)));
-
-	if (shdr->sh_type == SHT_STRTAB)
-		strtab = (unsigned char *)(addr + (ulong)shdr->sh_offset);
-
-	/* Load each appropriate section */
-	for (i = 0; i < ehdr->e_shnum; ++i) {
-		shdr = (Elf64_Shdr *)(addr + (ulong)ehdr->e_shoff +
-				     (i * sizeof(Elf64_Shdr)));
-
-		if (!(shdr->sh_flags & SHF_ALLOC) ||
-		    shdr->sh_addr == 0 || shdr->sh_size == 0) {
-			continue;
-		}
-
-		if (strtab) {
-			debug("%sing %s @ 0x%08lx (%ld bytes)\n",
-			      (shdr->sh_type == SHT_NOBITS) ? "Clear" : "Load",
-			       &strtab[shdr->sh_name],
-			       (unsigned long)shdr->sh_addr,
-			       (long)shdr->sh_size);
-		}
-
-		if (shdr->sh_type == SHT_NOBITS) {
-			memset((void *)(uintptr_t)shdr->sh_addr, 0,
-			       shdr->sh_size);
-		} else {
-			image = (unsigned char *)addr + (ulong)shdr->sh_offset;
-			memcpy((void *)(uintptr_t)shdr->sh_addr,
-			       (const void *)image, shdr->sh_size);
-		}
-		flush_cache(rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN),
-			    roundup((shdr->sh_addr + shdr->sh_size),
-				     ARCH_DMA_MINALIGN) -
-			            rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN));
-	}
-
-	if (ehdr->e_machine == EM_PPC64 && (ehdr->e_flags &
-					    EF_PPC64_ELFV1_ABI)) {
-		/*
-		 * For the 64-bit PowerPC ELF V1 ABI, e_entry is a function
-		 * descriptor pointer with the first double word being the
-		 * address of the entry point of the function.
-		 */
-		uintptr_t addr = ehdr->e_entry;
-
-		return *(Elf64_Addr *)addr;
-	}
-
-	return ehdr->e_entry;
-}
-
-/*
- * A very simple ELF loader, assumes the image is valid, returns the
- * entry point address.
- *
- * The loader firstly reads the EFI class to see if it's a 64-bit image.
- * If yes, call the ELF64 loader. Otherwise continue with the ELF32 loader.
- */
-static unsigned long load_elf_image_phdr(unsigned long addr)
-{
-	Elf32_Ehdr *ehdr; /* Elf header structure pointer */
-	Elf32_Phdr *phdr; /* Program header structure pointer */
-	int i;
-
-	ehdr = (Elf32_Ehdr *)addr;
-	if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
-		return load_elf64_image_phdr(addr);
-
-	phdr = (Elf32_Phdr *)(addr + ehdr->e_phoff);
-
-	/* Load each program header */
-	for (i = 0; i < ehdr->e_phnum; ++i) {
-		void *dst = (void *)(uintptr_t)phdr->p_paddr;
-		void *src = (void *)addr + phdr->p_offset;
-
-		debug("Loading phdr %i to 0x%p (%i bytes)\n",
-		      i, dst, phdr->p_filesz);
-		if (phdr->p_filesz)
-			memcpy(dst, src, phdr->p_filesz);
-		if (phdr->p_filesz != phdr->p_memsz)
-			memset(dst + phdr->p_filesz, 0x00,
-			       phdr->p_memsz - phdr->p_filesz);
-		flush_cache(rounddown((unsigned long)dst, ARCH_DMA_MINALIGN),
-			    roundup(phdr->p_memsz, ARCH_DMA_MINALIGN));
-		++phdr;
-	}
-
-	return ehdr->e_entry;
-}
-
-static unsigned long load_elf_image_shdr(unsigned long addr)
-{
-	Elf32_Ehdr *ehdr; /* Elf header structure pointer */
-	Elf32_Shdr *shdr; /* Section header structure pointer */
-	unsigned char *strtab = 0; /* String table pointer */
-	unsigned char *image; /* Binary image pointer */
-	int i; /* Loop counter */
-
-	ehdr = (Elf32_Ehdr *)addr;
-	if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
-		return load_elf64_image_shdr(addr);
-
-	/* Find the section header string table for output info */
-	shdr = (Elf32_Shdr *)(addr + ehdr->e_shoff +
-			     (ehdr->e_shstrndx * sizeof(Elf32_Shdr)));
-
-	if (shdr->sh_type == SHT_STRTAB)
-		strtab = (unsigned char *)(addr + shdr->sh_offset);
-
-	/* Load each appropriate section */
-	for (i = 0; i < ehdr->e_shnum; ++i) {
-		shdr = (Elf32_Shdr *)(addr + ehdr->e_shoff +
-				     (i * sizeof(Elf32_Shdr)));
-
-		if (!(shdr->sh_flags & SHF_ALLOC) ||
-		    shdr->sh_addr == 0 || shdr->sh_size == 0) {
-			continue;
-		}
-
-		if (strtab) {
-			debug("%sing %s @ 0x%08lx (%ld bytes)\n",
-			      (shdr->sh_type == SHT_NOBITS) ? "Clear" : "Load",
-			       &strtab[shdr->sh_name],
-			       (unsigned long)shdr->sh_addr,
-			       (long)shdr->sh_size);
-		}
-
-		if (shdr->sh_type == SHT_NOBITS) {
-			memset((void *)(uintptr_t)shdr->sh_addr, 0,
-			       shdr->sh_size);
-		} else {
-			image = (unsigned char *)addr + shdr->sh_offset;
-			memcpy((void *)(uintptr_t)shdr->sh_addr,
-			       (const void *)image, shdr->sh_size);
-		}
-		flush_cache(rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN),
-			    roundup((shdr->sh_addr + shdr->sh_size),
-				    ARCH_DMA_MINALIGN) -
-			    rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN));
-	}
-
-	return ehdr->e_entry;
-}
-
 /* Allow ports to override the default behavior */
 static unsigned long do_bootelf_exec(ulong (*entry)(int, char * const[]),
 				     int argc, char * const argv[])
@@ -238,30 +33,6 @@ static unsigned long do_bootelf_exec(ulong (*entry)(int, char * const[]),
 	return ret;
 }
 
-/*
- * Determine if a valid ELF image exists at the given memory location.
- * First look at the ELF header magic field, then make sure that it is
- * executable.
- */
-int valid_elf_image(unsigned long addr)
-{
-	Elf32_Ehdr *ehdr; /* Elf header structure pointer */
-
-	ehdr = (Elf32_Ehdr *)addr;
-
-	if (!IS_ELF(*ehdr)) {
-		printf("## No elf image at address 0x%08lx\n", addr);
-		return 0;
-	}
-
-	if (ehdr->e_type != ET_EXEC) {
-		printf("## Not a 32-bit elf image at address 0x%08lx\n", addr);
-		return 0;
-	}
-
-	return 1;
-}
-
 /* Interpreter command to boot an arbitrary ELF image from memory */
 int do_bootelf(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
diff --git a/include/elf.h b/include/elf.h
index 81f4019..e7c5198 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -692,6 +692,10 @@ unsigned long elf_hash(const unsigned char *name);
 
 #ifndef __ASSEMBLER__
 int valid_elf_image(unsigned long addr);
+unsigned long load_elf64_image_phdr(unsigned long addr);
+unsigned long load_elf64_image_shdr(unsigned long addr);
+unsigned long load_elf_image_phdr(unsigned long addr);
+unsigned long load_elf_image_shdr(unsigned long addr);
 #endif
 
 #endif /* _ELF_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index ab6aff7..452f390 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -602,4 +602,10 @@ config TEST_FDTDEC
 config LIB_DATE
 	bool
 
+config LIB_ELF
+	bool
+	help
+	  Supoort basic elf loading/validating functions.
+	  This supports fir 32 bit and 64 bit versions.
+
 endmenu
diff --git a/lib/Makefile b/lib/Makefile
index 15259d0..32bf3f3 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -122,6 +122,7 @@ obj-y += vsprintf.o strto.o
 endif
 
 obj-y += date.o
+obj-$(CONFIG_LIB_ELF) += elf.o
 
 #
 # Build a fast OID lookup registry from include/linux/oid_registry.h
diff --git a/lib/elf.c b/lib/elf.c
new file mode 100644
index 0000000..d074e4e
--- /dev/null
+++ b/lib/elf.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: BSD-2-Clause
+/*
+   Copyright (c) 2001 William L. Pitts
+*/
+
+#include <common.h>
+#include <command.h>
+#include <cpu_func.h>
+#include <elf.h>
+#include <env.h>
+#include <net.h>
+#include <vxworks.h>
+#ifdef CONFIG_X86
+#include <vbe.h>
+#include <asm/e820.h>
+#include <linux/linkage.h>
+#endif
+
+/*
+ * A very simple ELF64 loader, assumes the image is valid, returns the
+ * entry point address.
+ *
+ * Note if U-Boot is 32-bit, the loader assumes the to segment's
+ * physical address and size is within the lower 32-bit address space.
+ */
+unsigned long load_elf64_image_phdr(unsigned long addr)
+{
+	Elf64_Ehdr *ehdr; /* Elf header structure pointer */
+	Elf64_Phdr *phdr; /* Program header structure pointer */
+	int i;
+
+	ehdr = (Elf64_Ehdr *)addr;
+	phdr = (Elf64_Phdr *)(addr + (ulong)ehdr->e_phoff);
+
+	/* Load each program header */
+	for (i = 0; i < ehdr->e_phnum; ++i) {
+		void *dst = (void *)(ulong)phdr->p_paddr;
+		void *src = (void *)addr + phdr->p_offset;
+
+		debug("Loading phdr %i to 0x%p (%lu bytes)\n",
+		      i, dst, (ulong)phdr->p_filesz);
+		if (phdr->p_filesz)
+			memcpy(dst, src, phdr->p_filesz);
+		if (phdr->p_filesz != phdr->p_memsz)
+			memset(dst + phdr->p_filesz, 0x00,
+			       phdr->p_memsz - phdr->p_filesz);
+		flush_cache(rounddown((unsigned long)dst, ARCH_DMA_MINALIGN),
+			    roundup(phdr->p_memsz, ARCH_DMA_MINALIGN));
+		++phdr;
+	}
+
+	if (ehdr->e_machine == EM_PPC64 && (ehdr->e_flags &
+					    EF_PPC64_ELFV1_ABI)) {
+		/*
+		 * For the 64-bit PowerPC ELF V1 ABI, e_entry is a function
+		 * descriptor pointer with the first double word being the
+		 * address of the entry point of the function.
+		 */
+		uintptr_t addr = ehdr->e_entry;
+
+		return *(Elf64_Addr *)addr;
+	}
+
+	return ehdr->e_entry;
+}
+
+unsigned long load_elf64_image_shdr(unsigned long addr)
+{
+	Elf64_Ehdr *ehdr; /* Elf header structure pointer */
+	Elf64_Shdr *shdr; /* Section header structure pointer */
+	unsigned char *strtab = 0; /* String table pointer */
+	unsigned char *image; /* Binary image pointer */
+	int i; /* Loop counter */
+
+	ehdr = (Elf64_Ehdr *)addr;
+
+	/* Find the section header string table for output info */
+	shdr = (Elf64_Shdr *)(addr + (ulong)ehdr->e_shoff +
+			     (ehdr->e_shstrndx * sizeof(Elf64_Shdr)));
+
+	if (shdr->sh_type == SHT_STRTAB)
+		strtab = (unsigned char *)(addr + (ulong)shdr->sh_offset);
+
+	/* Load each appropriate section */
+	for (i = 0; i < ehdr->e_shnum; ++i) {
+		shdr = (Elf64_Shdr *)(addr + (ulong)ehdr->e_shoff +
+				     (i * sizeof(Elf64_Shdr)));
+
+		if (!(shdr->sh_flags & SHF_ALLOC) ||
+		    shdr->sh_addr == 0 || shdr->sh_size == 0) {
+			continue;
+		}
+
+		if (strtab) {
+			debug("%sing %s @ 0x%08lx (%ld bytes)\n",
+			      (shdr->sh_type == SHT_NOBITS) ? "Clear" : "Load",
+			       &strtab[shdr->sh_name],
+			       (unsigned long)shdr->sh_addr,
+			       (long)shdr->sh_size);
+		}
+
+		if (shdr->sh_type == SHT_NOBITS) {
+			memset((void *)(uintptr_t)shdr->sh_addr, 0,
+			       shdr->sh_size);
+		} else {
+			image = (unsigned char *)addr + (ulong)shdr->sh_offset;
+			memcpy((void *)(uintptr_t)shdr->sh_addr,
+			       (const void *)image, shdr->sh_size);
+		}
+		flush_cache(rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN),
+			    roundup((shdr->sh_addr + shdr->sh_size),
+				     ARCH_DMA_MINALIGN) -
+				rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN));
+	}
+
+	if (ehdr->e_machine == EM_PPC64 && (ehdr->e_flags &
+					    EF_PPC64_ELFV1_ABI)) {
+		/*
+		 * For the 64-bit PowerPC ELF V1 ABI, e_entry is a function
+		 * descriptor pointer with the first double word being the
+		 * address of the entry point of the function.
+		 */
+		uintptr_t addr = ehdr->e_entry;
+
+		return *(Elf64_Addr *)addr;
+	}
+
+	return ehdr->e_entry;
+}
+
+/*
+ * A very simple ELF loader, assumes the image is valid, returns the
+ * entry point address.
+ *
+ * The loader firstly reads the EFI class to see if it's a 64-bit image.
+ * If yes, call the ELF64 loader. Otherwise continue with the ELF32 loader.
+ */
+unsigned long load_elf_image_phdr(unsigned long addr)
+{
+	Elf32_Ehdr *ehdr; /* Elf header structure pointer */
+	Elf32_Phdr *phdr; /* Program header structure pointer */
+	int i;
+
+	ehdr = (Elf32_Ehdr *)addr;
+	if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
+		return load_elf64_image_phdr(addr);
+
+	phdr = (Elf32_Phdr *)(addr + ehdr->e_phoff);
+
+	/* Load each program header */
+	for (i = 0; i < ehdr->e_phnum; ++i) {
+		void *dst = (void *)(uintptr_t)phdr->p_paddr;
+		void *src = (void *)addr + phdr->p_offset;
+
+		debug("Loading phdr %i to 0x%p (%i bytes)\n",
+		      i, dst, phdr->p_filesz);
+		if (phdr->p_filesz)
+			memcpy(dst, src, phdr->p_filesz);
+		if (phdr->p_filesz != phdr->p_memsz)
+			memset(dst + phdr->p_filesz, 0x00,
+			       phdr->p_memsz - phdr->p_filesz);
+		flush_cache(rounddown((unsigned long)dst, ARCH_DMA_MINALIGN),
+			    roundup(phdr->p_memsz, ARCH_DMA_MINALIGN));
+		++phdr;
+	}
+
+	return ehdr->e_entry;
+}
+
+unsigned long load_elf_image_shdr(unsigned long addr)
+{
+	Elf32_Ehdr *ehdr; /* Elf header structure pointer */
+	Elf32_Shdr *shdr; /* Section header structure pointer */
+	unsigned char *strtab = 0; /* String table pointer */
+	unsigned char *image; /* Binary image pointer */
+	int i; /* Loop counter */
+
+	ehdr = (Elf32_Ehdr *)addr;
+	if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
+		return load_elf64_image_shdr(addr);
+
+	/* Find the section header string table for output info */
+	shdr = (Elf32_Shdr *)(addr + ehdr->e_shoff +
+			     (ehdr->e_shstrndx * sizeof(Elf32_Shdr)));
+
+	if (shdr->sh_type == SHT_STRTAB)
+		strtab = (unsigned char *)(addr + shdr->sh_offset);
+
+	/* Load each appropriate section */
+	for (i = 0; i < ehdr->e_shnum; ++i) {
+		shdr = (Elf32_Shdr *)(addr + ehdr->e_shoff +
+				     (i * sizeof(Elf32_Shdr)));
+
+		if (!(shdr->sh_flags & SHF_ALLOC) ||
+		    shdr->sh_addr == 0 || shdr->sh_size == 0) {
+			continue;
+		}
+
+		if (strtab) {
+			debug("%sing %s @ 0x%08lx (%ld bytes)\n",
+			      (shdr->sh_type == SHT_NOBITS) ? "Clear" : "Load",
+			       &strtab[shdr->sh_name],
+			       (unsigned long)shdr->sh_addr,
+			       (long)shdr->sh_size);
+		}
+
+		if (shdr->sh_type == SHT_NOBITS) {
+			memset((void *)(uintptr_t)shdr->sh_addr, 0,
+			       shdr->sh_size);
+		} else {
+			image = (unsigned char *)addr + shdr->sh_offset;
+			memcpy((void *)(uintptr_t)shdr->sh_addr,
+			       (const void *)image, shdr->sh_size);
+		}
+		flush_cache(rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN),
+			    roundup((shdr->sh_addr + shdr->sh_size),
+				    ARCH_DMA_MINALIGN) -
+			    rounddown(shdr->sh_addr, ARCH_DMA_MINALIGN));
+	}
+
+	return ehdr->e_entry;
+}
+
+/*
+ * Determine if a valid ELF image exists at the given memory location.
+ * First look at the ELF header magic field, then make sure that it is
+ * executable.
+ */
+int valid_elf_image(unsigned long addr)
+{
+	Elf32_Ehdr *ehdr; /* Elf header structure pointer */
+
+	ehdr = (Elf32_Ehdr *)addr;
+
+	if (!IS_ELF(*ehdr)) {
+		printf("## No elf image at address 0x%08lx\n", addr);
+		return 0;
+	}
+
+	if (ehdr->e_type != ET_EXEC) {
+		printf("## Not a 32-bit elf image at address 0x%08lx\n", addr);
+		return 0;
+	}
+
+	return 1;
+}