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>

1 files changed, 246 insertions, 0 deletions

diff --git a/lib/elf.c b/lib/elf.c
new file mode 100644
index 0000000000..d074e4e0a7
--- /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;
+}