117 lines
2.4 KiB
C++
117 lines
2.4 KiB
C++
/**
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* \brief GCC excption handling support
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* \author Sebastian Sumpf
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* \date 2015-03-12
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*/
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/*
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* Copyright (C) 2015 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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#include <linker.h>
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using namespace Linker;
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/*********
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** x86 **
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*********/
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/**
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* "Walk through shared objects" support, see man page of 'dl_iterate_phdr'
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*/
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struct Phdr_info
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{
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Elf::Addr addr; /* module relocation base */
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char const *name; /* module name */
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Elf::Phdr const *phdr; /* pointer to module's phdr */
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Elf::Half phnum; /* number of entries in phdr */
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};
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extern "C" int dl_iterate_phdr(int (*callback) (Phdr_info *info, Genode::size_t size, void *data), void *data)
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{
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int err = 0;
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Phdr_info info;
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Genode::Lock::Guard guard(Object::lock());
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for (Object *e = obj_list_head();e; e = e->next_obj()) {
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info.addr = e->reloc_base();
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info.name = e->name();
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info.phdr = e->file()->phdr.phdr;
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info.phnum = e->file()->phdr.count;
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if (verbose_exception)
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PDBG("%s reloc " EFMT, e->name(), e->reloc_base());
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if ((err = callback(&info, sizeof(Phdr_info), data)))
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break;
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}
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return err;
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}
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/*********
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** ARM **
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*********/
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/**
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* Return EXIDX program header
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*/
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static Elf::Phdr const *phdr_exidx(File const *file)
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{
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for (unsigned i = 0; i < file->elf_phdr_count(); i++) {
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Elf::Phdr const *ph = file->elf_phdr(i);
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if (ph->p_type == PT_ARM_EXIDX)
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return ph;
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}
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return 0;
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}
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/**
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* Find ELF and exceptions table segment that that is located under 'pc',
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* address of exception table and number of entries 'pcount'
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*/
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extern "C" unsigned long dl_unwind_find_exidx(unsigned long pc, int *pcount)
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{
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/* size of exception table entries */
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enum { EXIDX_ENTRY_SIZE = 8 };
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*pcount = 0;
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/*
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* Since this function may be called before the main function, load linker's
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* program header now
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*/
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load_linker_phdr();
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for (Object *e = obj_list_head(); e; e = e->next_obj())
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{
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/* address of first PT_LOAD header */
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Genode::addr_t base = e->reloc_base() + e->file()->start;
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/* is the 'pc' somewhere within this ELF image */
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if ((pc < base) || (pc >= base + e->file()->size))
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continue;
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/* retrieve PHDR of exception-table segment */
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Elf::Phdr const *exidx = phdr_exidx(e->file());
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if (!exidx)
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continue;
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*pcount = exidx->p_memsz / EXIDX_ENTRY_SIZE;
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return exidx->p_vaddr + e->reloc_base();
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}
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return 0;
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}
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