nuttx/libs/libc/machine/xtensa/arch_elf.c

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/****************************************************************************
* libs/libc/machine/xtensa/arch_elf.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
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#include <assert.h>
#include <stdlib.h>
#include <errno.h>
#include <debug.h>
#include <arch/elf.h>
#include <nuttx/elf.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
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static bool is_l32r(FAR const unsigned char *p)
{
return (p[0] & 0xf) == 1;
}
/****************************************************************************
* 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 Xtensa executable */
if (ehdr->e_machine != EM_XTENSA)
{
berr("ERROR: Not for Xtensa: e_machine=%04x\n", ehdr->e_machine);
return false;
}
/* Make sure that 32-bit objects are supported */
if (ehdr->e_ident[EI_CLASS] != ELFCLASS32)
{
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berr("ERROR: Need 32-bit objects: e_ident[EI_CLASS]=%02x\n",
ehdr->e_ident[EI_CLASS]);
return false;
}
/* Verify endian-ness */
#ifdef CONFIG_ENDIAN_BIG
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#error not implemented
if (ehdr->e_ident[EI_DATA] != ELFDATA2MSB)
#else
if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
#endif
{
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berr("ERROR: Wrong endian-ness: e_ident[EI_DATA]=%02x\n",
ehdr->e_ident[EI_DATA]);
return false;
}
return true;
}
/****************************************************************************
* 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)
{
unsigned int relotype;
/* All relocations except NONE depend upon having valid symbol
* information.
*/
relotype = ELF32_R_TYPE(rel->r_info);
if (sym == NULL && relotype != R_XTENSA_NONE)
{
return -EINVAL;
}
/* Handle the relocation by relocation type */
switch (relotype)
{
case R_XTENSA_NONE:
{
/* No relocation */
}
break;
default:
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berr("ERROR: Unsupported relocation: %u\n", relotype);
return -EINVAL;
}
return OK;
}
int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym,
uintptr_t addr)
{
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unsigned int relotype;
unsigned char *p;
uint32_t value;
relotype = ELF32_R_TYPE(rel->r_info);
value = sym->st_value + rel->r_addend;
/* Handle the relocation by relocation type */
switch (relotype)
{
case R_XTENSA_32:
(*(FAR uint32_t *)addr) += value;
break;
case R_XTENSA_ASM_EXPAND:
bwarn("WARNING: Ignoring RELA relocation R_XTENSA_ASM_EXPAND %u\n",
relotype);
break;
case R_XTENSA_SLOT0_OP:
p = (FAR unsigned char *)addr;
if (is_l32r(p))
{
/* Xtensa ISA:
* L32R forms a virtual address by adding the 16-bit one-extended
* constant value encoded in the instruction word shifted left by
* two to the address of the L32R plus three with the two least
* significant bits cleared.
*/
uintptr_t base = (addr + 3) & ~3;
uint16_t imm = (value - base) >> 2;
if (base + (0xfffc0000 | ((uint32_t)imm << 2)) != value)
{
berr("ERROR: Out of range rellocation at %p\n", p);
return -EINVAL;
}
p[1] = imm & 0xff;
p[2] = (imm >> 8) & 0xff;
break;
}
bwarn("WARNING: Ignoring RELA relocation R_XTENSA_SLOT0_OP %u\n",
relotype);
break;
default:
berr("ERROR: RELA relocation %u not supported\n", relotype);
return -EINVAL;
}
return OK;
}