996625ec58
There is a problem with the current elf loader for risc-v: when a pair of PCREL_HI20 / LO12 relocations are encountered, it is assumed that these will follow each other immediately, as follows: label: auipc a0, %pcrel_hi(symbol) // R_RISCV_PCREL_HI20 load/store a0, %pcrel_lo(label)(a0) // R_RISCV_PCREL_LO12_I/S With this assumption, the hi/lo relocations are both done when a hi20 relocation entry is encountered, first to the current instruction (addr) and to the next instruction (addr + 4). However, this assumption is wrong. There is nothing in the elf relocation specification[1] that mandates this. Thus, the hi/lo relocation always needs to first fixup the hi-part, and when the lo-part is encountered, it needs to find the corresponding hi relocation entry, via the given "label". This necessitates (re-)visiting the relocation entries for the current section as well as looking for "label" in the symbol table. The NuttX elf loader does not allow such operations to be done in the machine specific part, so this patch fixes the relocation issue by introducing an architecture specific cache for the hi20 relocation and symbol table entries. When a lo12 relocation is encountered, the cache can be consulted to find the hi20 part. [1] https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc
175 lines
6.0 KiB
C
175 lines
6.0 KiB
C
/****************************************************************************
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* include/nuttx/elf.h
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __INCLUDE_NUTTX_ELF_H
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#define __INCLUDE_NUTTX_ELF_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <elf.h>
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#include <arch/elf.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define ELF_PRARGSZ (80) /* Number of chars for args */
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/****************************************************************************
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* Public Types
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****************************************************************************/
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#ifdef CONFIG_ELF_COREDUMP
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typedef struct elf_prpsinfo_s
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{
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char pr_state; /* Numeric process state */
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char pr_sname; /* Char for pr_state */
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char pr_zomb; /* Zombie */
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char pr_nice; /* Nice val */
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unsigned long pr_flag; /* Flags */
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unsigned short pr_uid;
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unsigned short pr_gid;
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int pr_pid;
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int pr_ppid;
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int pr_pgrp;
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int pr_sid;
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char pr_fname[16]; /* Filename of executable */
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char pr_psargs[ELF_PRARGSZ]; /* Initial part of arg list */
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} elf_prpsinfo_t;
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typedef struct elf_siginfo_s
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{
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int si_signo; /* Signal number */
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int si_code; /* Extra code */
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int si_errno; /* Errno */
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} elf_siginfo_t;
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typedef struct elf_timeval_s
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{
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long tv_sec; /* Seconds */
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long tv_usec; /* Microseconds */
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} elf_timeval_t;
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typedef struct elf_prstatus_s
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{
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elf_siginfo_t pr_info; /* Info associated with signal */
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short pr_cursig; /* Current signal */
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short pr_padding; /* Padding align */
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unsigned long pr_sigpend; /* Set of pending signals */
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unsigned long pr_sighold; /* Set of held signals */
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int pr_pid;
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int pr_ppid;
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int pr_pgrp;
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int pr_sid;
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elf_timeval_t pr_utime; /* User time */
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elf_timeval_t pr_stime; /* System time */
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elf_timeval_t pr_cutime; /* Cumulative user time */
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elf_timeval_t pr_cstime; /* Cumulative system time */
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elf_gregset_t pr_regs;
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int pr_fpvalid; /* True if math co-processor being used */
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} elf_prstatus_t;
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#endif
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#if defined(__cplusplus)
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extern "C"
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{
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#endif
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/****************************************************************************
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* Name: up_checkarch
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*
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* Description:
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* Given the ELF header in 'hdr', verify that the module is appropriate
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* for the current, configured architecture. Every architecture that uses
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* the module loader must provide this function.
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*
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* Input Parameters:
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* hdr - The ELF header read from the module file.
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*
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* Returned Value:
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* True if the architecture supports this module file.
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*
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****************************************************************************/
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#ifdef CONFIG_LIBC_ARCH_ELF
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bool up_checkarch(FAR const Elf_Ehdr *hdr);
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#endif
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/****************************************************************************
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* Name: up_relocate and up_relocateadd
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*
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* Description:
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* Perform on architecture-specific ELF relocation. Every architecture
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* that uses the module loader must provide this function.
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*
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* Input Parameters:
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* rel - The relocation type
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* sym - The ELF symbol structure containing the fully resolved value.
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* There are a few relocation types for a few architectures that do
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* not require symbol information. For those, this value will be
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* NULL. Implementations of these functions must be able to handle
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* that case.
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* addr - The address that requires the relocation.
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*
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* Returned Value:
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* Zero (OK) if the relocation was successful. Otherwise, a negated errno
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* value indicating the cause of the relocation failure.
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*
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****************************************************************************/
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#ifdef CONFIG_LIBC_ARCH_ELF
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int up_relocate(FAR const Elf_Rel *rel, FAR const Elf_Sym *sym,
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uintptr_t addr, FAR void *arch_data);
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int up_relocateadd(FAR const Elf_Rela *rel, FAR const Elf_Sym *sym,
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uintptr_t addr, FAR void *arch_data);
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#endif
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/****************************************************************************
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* Name: up_init_exidx
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*
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* Description:
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* Initialize the exception index section.
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*
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* Input Parameters:
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* address - The exception index section address.
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* size - The exception index section size.
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*
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* Returned Value:
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* Zero (OK) if the initialization was successful. Otherwise, a negated
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* errno value indicating the cause of the failure.
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*
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****************************************************************************/
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#ifdef CONFIG_CXX_EXCEPTION
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int up_init_exidx(Elf_Addr address, Elf_Word size);
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#endif
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#if defined(__cplusplus)
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}
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#endif
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#endif /* __INCLUDE_NUTTX_ELF_H */
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