/****************************************************************************
* arch/arm/src/armv-7a/arm_elf.c
*
* Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdlib.h>
#include <elf32.h>
#include <errno.h>
#include <debug.h>
#include <arch/elf.h>
#include <nuttx/arch.h>
#include <nuttx/binfmt/elf.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_checkarch
*
* Description:
* Given the ELF header in 'hdr', verify that the ELF file is appropriate
* for the current, configured architecture. Every architecture that uses
* the ELF loader must provide this function.
*
* Input Parameters:
* hdr - The ELF header read from the ELF file.
*
* Returned Value:
* True if the architecture supports this ELF file.
*
****************************************************************************/
bool up_checkarch(FAR const Elf32_Ehdr *ehdr)
{
/* Make sure it's an ARM executable */
if (ehdr->e_machine != EM_ARM)
{
bdbg("Not for ARM: e_machine=%04x\n", ehdr->e_machine);
return -ENOEXEC;
}
/* Make sure that 32-bit objects are supported */
if (ehdr->e_ident[EI_CLASS] != ELFCLASS32)
{
bdbg("Need 32-bit objects: e_ident[EI_CLASS]=%02x\n", ehdr->e_ident[EI_CLASS]);
return -ENOEXEC;
}
/* Verify endian-ness */
#ifdef CONFIG_ENDIAN_BIG
if (ehdr->e_ident[EI_DATA] != ELFDATA2MSB)
#else
if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
#endif
{
bdbg("Wrong endian-ness: e_ident[EI_DATA]=%02x\n", ehdr->e_ident[EI_DATA]);
return -ENOEXEC;
}
/* Make sure the entry point address is properly aligned */
if ((ehdr->e_entry & 3) != 0)
{
bdbg("Entry point is not properly aligned: %08x\n", ehdr->e_entry);
return -ENOEXEC;
}
/* TODO: Check ABI here. */
return OK;
}
/****************************************************************************
* Name: up_relocate and up_relocateadd
*
* Description:
* Perform on architecture-specific ELF relocation. Every architecture
* that uses the ELF loader must provide this function.
*
* Input Parameters:
* rel - The relocation type
* sym - The ELF symbol structure containing the fully resolved value.
* There are a few relocation types for a few architectures that do
* not require symbol information. For those, this value will be
* NULL. Implementations of these functions must be able to handle
* that case.
* addr - The address that requires the relocation.
*
* Returned Value:
* Zero (OK) if the relocation was successful. Otherwise, a negated errno
* value indicating the cause of the relocation failure.
*
****************************************************************************/
int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
uintptr_t addr)
{
int32_t offset;
unsigned int relotype;
/* All relocations except R_ARM_V4BX depend upon having valid symbol
* information.
*/
relotype = ELF32_R_TYPE(rel->r_info);
if (sym == NULL && relotype != R_ARM_NONE && relotype != R_ARM_V4BX)
{
return -EINVAL;
}
/* Handle the relocation by relocation type */
switch (relotype)
{
case R_ARM_NONE:
{
/* No relocation */
}
break;
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
{
bvdbg("Performing PC24 [%d] link at addr %08lx [%08lx] to sym '%s' st_value=%08lx\n",
ELF32_R_TYPE(rel->r_info), (long)addr, (long)(*(uint32_t*)addr),
sym, (long)sym->st_value);
offset = (*(uint32_t*)addr & 0x00ffffff) << 2;
if (offset & 0x02000000)
{
offset -= 0x04000000;
}
offset += sym->st_value - addr;
if (offset & 3 || offset <= (int32_t) 0xfe000000 || offset >= (int32_t) 0x02000000)
{
bdbg(" ERROR: PC24 [%d] relocation out of range, offset=%08lx\n",
ELF32_R_TYPE(rel->r_info), offset);
return -EINVAL;
}
offset >>= 2;
*(uint32_t*)addr &= 0xff000000;
*(uint32_t*)addr |= offset & 0x00ffffff;
}
break;
case R_ARM_ABS32:
case R_ARM_TARGET1: /* New ABI: TARGET1 always treated as ABS32 */
{
bvdbg("Performing ABS32 link at addr=%08lx [%08lx] to sym=%p st_value=%08lx\n",
(long)addr, (long)(*(uint32_t*)addr), sym, (long)sym->st_value);
*(uint32_t*)addr += sym->st_value;
}
break;
case R_ARM_V4BX:
{
bvdbg("Performing V4BX link at addr=%08lx [%08lx]\n",
(long)addr, (long)(*(uint32_t*)addr));
/* Preserve only Rm and the condition code */
*(uint32_t*)addr &= 0xf000000f;
/* Change instruction to 'mov pc, Rm' */
*(uint32_t*)addr |= 0x01a0f000;
}
break;
case R_ARM_PREL31:
{
bvdbg("Performing PREL31 link at addr=%08lx [%08lx] to sym=%p st_value=%08lx\n",
(long)addr, (long)(*(uint32_t*)addr), sym, (long)sym->st_value);
offset = *(uint32_t*)addr + sym->st_value - addr;
*(uint32_t*)addr = offset & 0x7fffffff;
}
break;
case R_ARM_MOVW_ABS_NC:
case R_ARM_MOVT_ABS:
{
bvdbg("Performing MOVx_ABS [%d] link at addr=%08lx [%08lx] to sym=%p st_value=%08lx\n",
ELF32_R_TYPE(rel->r_info), (long)addr, (long)(*(uint32_t*)addr),
sym, (long)sym->st_value);
offset = *(uint32_t*)addr;
offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff);
offset = (offset ^ 0x8000) - 0x8000;
offset += sym->st_value;
if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS)
{
offset >>= 16;
}
*(uint32_t*)addr &= 0xfff0f000;
*(uint32_t*)addr |= ((offset & 0xf000) << 4) | (offset & 0x0fff);
}
break;
default:
bdbg("Unsupported relocation: %d\n", ELF32_R_TYPE(rel->r_info));
return -EINVAL;
}
return OK;
}
int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym,
uintptr_t addr)
{
bdbg("RELA relocation not supported\n");
return -ENOSYS;
}
