549e8152de
This implements CONFIG_RELOCATABLE for 64-bit by making the kernel as a position-independent executable (PIE) when it is set. This involves processing the dynamic relocations in the image in the early stages of booting, even if the kernel is being run at the address it is linked at, since the linker does not necessarily fill in words in the image for which there are dynamic relocations. (In fact the linker does fill in such words for 64-bit executables, though not for 32-bit executables, so in principle we could avoid calling relocate() entirely when we're running a 64-bit kernel at the linked address.) The dynamic relocations are processed by a new function relocate(addr), where the addr parameter is the virtual address where the image will be run. In fact we call it twice; once before calling prom_init, and again when starting the main kernel. This means that reloc_offset() returns 0 in prom_init (since it has been relocated to the address it is running at), which necessitated a few adjustments. This also changes __va and __pa to use an equivalent definition that is simpler. With the relocatable kernel, PAGE_OFFSET and MEMORY_START are constants (for 64-bit) whereas PHYSICAL_START is a variable (and KERNELBASE ideally should be too, but isn't yet). With this, relocatable kernels still copy themselves down to physical address 0 and run there. Signed-off-by: Paul Mackerras <paulus@samba.org>
79 lines
2.3 KiB
C
79 lines
2.3 KiB
C
/*
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* Copyright (C) Paul Mackerras 1997.
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*
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* Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <stdarg.h>
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#include <stddef.h>
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#include "elf.h"
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#include "page.h"
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#include "string.h"
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#include "stdio.h"
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int parse_elf64(void *hdr, struct elf_info *info)
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{
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Elf64_Ehdr *elf64 = hdr;
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Elf64_Phdr *elf64ph;
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unsigned int i;
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if (!(elf64->e_ident[EI_MAG0] == ELFMAG0 &&
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elf64->e_ident[EI_MAG1] == ELFMAG1 &&
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elf64->e_ident[EI_MAG2] == ELFMAG2 &&
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elf64->e_ident[EI_MAG3] == ELFMAG3 &&
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elf64->e_ident[EI_CLASS] == ELFCLASS64 &&
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elf64->e_ident[EI_DATA] == ELFDATA2MSB &&
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(elf64->e_type == ET_EXEC ||
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elf64->e_type == ET_DYN) &&
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elf64->e_machine == EM_PPC64))
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return 0;
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elf64ph = (Elf64_Phdr *)((unsigned long)elf64 +
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(unsigned long)elf64->e_phoff);
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for (i = 0; i < (unsigned int)elf64->e_phnum; i++, elf64ph++)
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if (elf64ph->p_type == PT_LOAD)
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break;
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if (i >= (unsigned int)elf64->e_phnum)
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return 0;
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info->loadsize = (unsigned long)elf64ph->p_filesz;
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info->memsize = (unsigned long)elf64ph->p_memsz;
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info->elfoffset = (unsigned long)elf64ph->p_offset;
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return 1;
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}
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int parse_elf32(void *hdr, struct elf_info *info)
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{
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Elf32_Ehdr *elf32 = hdr;
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Elf32_Phdr *elf32ph;
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unsigned int i;
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if (!(elf32->e_ident[EI_MAG0] == ELFMAG0 &&
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elf32->e_ident[EI_MAG1] == ELFMAG1 &&
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elf32->e_ident[EI_MAG2] == ELFMAG2 &&
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elf32->e_ident[EI_MAG3] == ELFMAG3 &&
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elf32->e_ident[EI_CLASS] == ELFCLASS32 &&
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elf32->e_ident[EI_DATA] == ELFDATA2MSB &&
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(elf32->e_type == ET_EXEC ||
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elf32->e_type == ET_DYN) &&
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elf32->e_machine == EM_PPC))
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return 0;
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elf32ph = (Elf32_Phdr *) ((unsigned long)elf32 + elf32->e_phoff);
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for (i = 0; i < elf32->e_phnum; i++, elf32ph++)
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if (elf32ph->p_type == PT_LOAD)
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break;
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if (i >= elf32->e_phnum)
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return 0;
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info->loadsize = elf32ph->p_filesz;
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info->memsize = elf32ph->p_memsz;
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info->elfoffset = elf32ph->p_offset;
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return 1;
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}
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