[PATCH v2 1/9] lib: elf: Move the generic elf loading/validating functions to lib

Keerthy j-keerthy at ti.com
Fri Jan 17 09:06:14 CET 2020



On 17/01/20 1:19 pm, Simon Goldschmidt wrote:
> On Fri, Jan 17, 2020 at 5:27 AM Lokesh Vutla <lokeshvutla at ti.com> wrote:
>>
>> Simon,
>>
>> On 13/01/20 11:24 AM, Keerthy wrote:
>>> Move the generic elf loading/validating functions to lib/
>>> so that they can be re-used and accessed by code existing
>>> outside cmd.
>>>
>>> Signed-off-by: Keerthy <j-keerthy at ti.com>
>>> Suggested-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>
>>
>> Are you okay with this patch? If yes, Ill apply to u-boot-ti along with other
>> patches in this series.
> 
> Yes.
> 
> Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt at gmail.com>

Thanks Simon!

> 
> Regards,
> Simon
> 
>>
>> Thanks and regards,
>> Lokesh
>>
>>> ---
>>> Changes in v2:
>>>
>>>    * Factored out all the generic elf handling functions under lib/elf.c
>>>
>>>   cmd/Kconfig   |   1 +
>>>   cmd/elf.c     | 229 --------------------------------------------
>>>   include/elf.h |   4 +
>>>   lib/Kconfig   |   3 +
>>>   lib/Makefile  |   1 +
>>>   lib/elf.c     | 256 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>>   6 files changed, 265 insertions(+), 229 deletions(-)
>>>   create mode 100644 lib/elf.c
>>>
>>> diff --git a/cmd/Kconfig b/cmd/Kconfig
>>> index 298feae24d..6f4f08d02a 100644
>>> --- a/cmd/Kconfig
>>> +++ b/cmd/Kconfig
>>> @@ -375,6 +375,7 @@ config CMD_ADTIMG
>>>   config CMD_ELF
>>>        bool "bootelf, bootvx"
>>>        default y
>>> +     select ELF
>>>        help
>>>          Boot an ELF/vxWorks image from the memory.
>>>
>>> diff --git a/cmd/elf.c b/cmd/elf.c
>>> index 32f12a72b9..23cc17aebc 100644
>>> --- a/cmd/elf.c
>>> +++ b/cmd/elf.c
>>> @@ -26,211 +26,6 @@
>>>   #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[])
>>> @@ -246,30 +41,6 @@ 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 81f40191d7..e7c51986df 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 d040a87d26..b155ced4b2 100644
>>> --- a/lib/Kconfig
>>> +++ b/lib/Kconfig
>>> @@ -601,4 +601,7 @@ config TEST_FDTDEC
>>>   config LIB_DATE
>>>        bool
>>>
>>> +config ELF
>>> +     bool "enable basic elf loading/validating functions"
>>> +
>>>   endmenu
>>> diff --git a/lib/Makefile b/lib/Makefile
>>> index 6b7b9ce85c..93f22d210e 100644
>>> --- a/lib/Makefile
>>> +++ b/lib/Makefile
>>> @@ -121,6 +121,7 @@ obj-y += vsprintf.o strto.o
>>>   endif
>>>
>>>   obj-y += date.o
>>> +obj-$(CONFIG_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 0000000000..54ac4ee502
>>> --- /dev/null
>>> +++ b/lib/elf.c
>>> @@ -0,0 +1,256 @@
>>> +/*
>>> + * Copyright (c) 2001 William L. Pitts
>>> + * All rights reserved.
>>> + *
>>> + * Redistribution and use in source and binary forms are freely
>>> + * permitted provided that the above copyright notice and this
>>> + * paragraph and the following disclaimer are duplicated in all
>>> + * such forms.
>>> + *
>>> + * This software is provided "AS IS" and without any express or
>>> + * implied warranties, including, without limitation, the implied
>>> + * warranties of merchantability and fitness for a particular
>>> + * purpose.
>>> + */
>>> +
>>> +#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;
>>> +}
>>>


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