On 11/12/2013 07:34 PM, Bernhard Reutner-Fischer wrote:
> I take it you double-checked the table below against the defines in
> include/elf.h
Yes.
>> +static const char *_dl_reltypes_tab[] =
>> +{
> +__asm__(
> + ".section .text \n"
> + ".balign 4 \n"
> + ".global _start \n"
> .hidden _start ?
yes both global + hidden. Otherwise ld can't seem to find it.
>> diff --git a/ldso/ldso/arc/dl-syscalls.h b/ldso/ldso/arc/dl-syscalls.h
>> new file mode 100644
>> index 000000000000..1ab7b552a217
>> --- /dev/null
>> +++ b/ldso/ldso/arc/dl-syscalls.h
>> @@ -0,0 +1,8 @@
>> +/*
>> + * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
>> + *
>> + * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>> + */
>> +
>> +#include "sys/syscall.h"
>> +#include <bits/uClibc_page.h>
> Sounds like it could go with the stub only?
Done.
>> diff --git a/ldso/ldso/arc/dl-sysdep.h b/ldso/ldso/arc/dl-sysdep.h
>> new file mode 100644
>> index 000000000000..642f020f42e1
>> --- /dev/null
>> +++ b/ldso/ldso/arc/dl-sysdep.h
>> @@ -0,0 +1,156 @@
>> +/*
>> + * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
>> + *
>> + * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>> + */
>> +
>> +#include "elf.h"
>> +
>> +/*
>> + * Define this if the system uses RELOCA.
>> + */
>> +#define ELF_USES_RELOCA
>> +
>> +/*
>> + * Dynamic Linking ABI for ARCompact ISA
>> + *
>> + * PLT
>> + * --------------------------------
>> + * | ld r11, [pcl, off-to-GOT[1] | 0 (20 bytes)
>> + * | | 4
>> + * plt0 | ld r10, [pcl, off-to-GOT[2] | 8
> table layout seems to be broken here
>
>> + * | | 12
>> + * | j [r10] | 16
>> + * --------------------------------
>> + * | Base address of GOT | 20
>> + * --------------------------------
>> + * | ld r12, [pcl, off-to-GOT[3] | 24 (12 bytes each)
>> + * plt1 | |
> .. and here.
All fixed.
>
>> + * | j_s.d [r12] | 32
>> + * | mov_s r12, pcl | 34
>> + * --------------------------------
>> + * | | 36
>> + * ~ ~
>> + * ~ ~
>> + * | |
>> + * --------------------------------
>> + *
>> + * GOT
>> + * --------------
>> + * | [0] |
>> + * --------------
>> + * | [1] | Module info - setup by ldso
>> + * --------------
>> + * | [2] | resolver entry point
>> + * --------------
>> + * | [3] |
>> + * | ... | Runtime address for function symbols
>> + * | [f] |
>> + * --------------
>> + * | [f+1] |
>> + * | ... | Runtime address for data symbols
>> + * | [last] |
>> + * --------------
>> + */
>> +
>> +/*
>> + * Initialization sequence for a GOT.
>> + * Caller elf_resolve() seeds @GOT_BASE from DT_PLTGOT - which essentially
>> is
>> + * pointer to first PLT entry. The actual GOT base is 5th word in PLT
>> + *
>> + */
>> +#define INIT_GOT(GOT_BASE,MODULE)
>> \
>> +do {
>> \
>> + unsigned long *__plt_base = (unsigned long *)GOT_BASE;
>> \
>> + if(MODULE->libtype != program_interpreter)
>> \
> you sure you need the above?
Nope, Now removed.
>> + GOT_BASE = (unsigned long *)(__plt_base[5] +
>> \
>> + (unsigned long)MODULE->loadaddr);
>> \
>> + GOT_BASE[1] = (unsigned long) MODULE;
>> \
>> + GOT_BASE[2] = (unsigned long) _dl_linux_resolve;
>> \
>> +} while(0)
>> +
>> +/* Here we define the magic numbers that this dynamic loader should accept
>> */
>> +#define MAGIC1 EM_ARCOMPACT
>> +#undef MAGIC2
>> +
>> +/* Used for error messages */
>> +#define ELF_TARGET "ARC"
>> +
>> +struct elf_resolve;
>> +extern unsigned long _dl_linux_resolver(struct elf_resolve * tpnt,
>> + unsigned int plt_pc);
>> +
>> +extern unsigned __udivmodsi4 (unsigned, unsigned)
>> + __attribute ((visibility("hidden")));
> yuck ;)
> And please use __foo__ throughout, for attribute, inline.
OK.
>> +
>> +#define do_rem(result, n, base) ((result) =
>> \
>> + \
>> + __builtin_constant_p (base) ? (n) % (unsigned) (base) : \
> I'd prefer if you marked that as (__extension__ ({
You mean
- ({ \
+ __extension__ ({ \
If so, done.
However I read man gcc for __extension__, but not sure how it applies here (and
only here).
>> + */
>> +static inline Elf32_Addr elf_machine_dynamic (void) attribute_unused;
>> +static inline Elf32_Addr
> Perhaps you want __always_inline and in similar spots?
Done for all three
>> +++ b/ldso/ldso/arc/elfinterp.c
>> @@ -0,0 +1,284 @@
>> +/*
>> + * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
>> + *
>> + * Lots of code copied from ../i386/elfinterp.c, so:
>> + * Copyright (c) 1994-2000 Eric Youngdale, Peter MacDonald,
>> + * David Engel, Hongjiu Lu and Mitch D'Souza
>> + * Copyright (C) 2001-2002, Erik Andersen
>> + * All rights reserved.
>> + *
>> + * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>> + */
>> +#include "ldso.h"
>> +
>> +unsigned long
>> +_dl_linux_resolver(struct elf_resolve *tpnt, unsigned int plt_pc)
>> +{
>> + ELF_RELOC *this_reloc, *rel_base;
>> + char *strtab, *symname, *new_addr;
>> + ElfW(Sym) *symtab;
>> + int symtab_index;
>> + unsigned int *got_addr;
>> + unsigned long plt_base;
>> + int plt_idx;
>> +
>> + /* start of .rela.plt */
>> + rel_base = (ELF_RELOC *)(tpnt->dynamic_info[DT_JMPREL]);
>> +
>> + /* starts of .plt (addr of PLT0) */
>> + plt_base = tpnt->dynamic_info[DT_PLTGOT];
>> +
>> + /*
>> + * compute the idx of the yet-unresolved PLT entry in .plt
>> + * Same idx will be used to find the relo entry in .rela.plt
>> + */
> whitespace damage above
Oops - fixed now.
>> + plt_idx = (plt_pc - plt_base)/0xc - 2; /* ignoring 2 dummy PLTs */
> magic 12 ?
Added/used #define ARC_PLT_SIZE 12
>> +
>> + this_reloc = rel_base + plt_idx;
>> +
>> + symtab_index = ELF_R_SYM(this_reloc->r_info);
>> + symtab = (ElfW(Sym) *)(intptr_t) (tpnt->dynamic_info[DT_SYMTAB]);
>> + strtab = (char *) (tpnt->dynamic_info[DT_STRTAB]);
>> + symname= strtab + symtab[symtab_index].st_name;
>> +
>> + /* relo-offset to fixup, shd be a .got entry */
>> + got_addr = (unsigned int *)(this_reloc->r_offset + tpnt->loadaddr);
>> +
>> + /* Get the address of the GOT entry */
>> + new_addr = _dl_find_hash(symname, &_dl_loaded_modules->symbol_scope,
>> tpnt,
>> + ELF_RTYPE_CLASS_PLT, NULL);
>> +
>> + if (unlikely(!new_addr)) {
>> + _dl_dprintf(2, "%s: can't resolve symbol '%s'\n", _dl_progname,
>> symname);
>> + _dl_exit(1);
>> + }
>> +
>> +
>> +#if defined (__SUPPORT_LD_DEBUG__)
> please remove braces
All fixed.
>> +static int
>> +_dl_do_lazy_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
>> + ELF_RELOC *rpnt);
>> +
>> +static int
>> +_dl_do_reloc (struct elf_resolve *tpnt, struct r_scope_elem *scope,
>> + ELF_RELOC *rpnt, ElfW(Sym) *symtab, char *strtab);
> Please restructure so you don't need these forward declarations.
Done.
>
> Also, it would be nice if you could switch to using a function pointer
> for the real handler, see all other arches.
I consciously did that micro-optimization to avoid the overhead of an indirect
function pointer for processing each symbol relo.
>> +}
>> diff --git a/ldso/ldso/arc/resolve.S b/ldso/ldso/arc/resolve.S
>> new file mode 100644
>> index 000000000000..8609b339effa
>> --- /dev/null
>> +++ b/ldso/ldso/arc/resolve.S
>> @@ -0,0 +1,59 @@
>> +/*
>> + * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
>> + *
>> + * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
>> + */
>> +
>> +#define __ASSEMBLY__
> please remove that define.
Done.
>> +
>> +#include <bits/asm.h>
> Can you instead of asm.h use ENTRY and PLTJMP et al from sysdep.h please?
> Everywhere.
I was afraid this will come up :-) Fixed now.
Also while at it, converted ENDFUNC -> END to make it more conventional.
Thanks for your review.
-Vineet
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