diff mbox series

[v6,02/13] ARC: startup and dynamic linking code

Message ID 20200423014126.10417-3-vgupta@synopsys.com
State Superseded
Headers show
Series glibc port to ARC processors | expand

Commit Message

Vineet Gupta April 23, 2020, 1:41 a.m. UTC
Code for C runtime startup and dynamic loading including PLT layout.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
---
 sysdeps/arc/bits/link.h   |  52 ++++++
 sysdeps/arc/dl-machine.h  | 340 ++++++++++++++++++++++++++++++++++++++
 sysdeps/arc/entry.h       |   5 +
 sysdeps/arc/ldsodefs.h    |  43 +++++
 sysdeps/arc/sotruss-lib.c |  51 ++++++
 sysdeps/arc/start.S       |  74 +++++++++
 sysdeps/arc/tst-audit.h   |  23 +++
 7 files changed, 588 insertions(+)
 create mode 100644 sysdeps/arc/bits/link.h
 create mode 100644 sysdeps/arc/dl-machine.h
 create mode 100644 sysdeps/arc/entry.h
 create mode 100644 sysdeps/arc/ldsodefs.h
 create mode 100644 sysdeps/arc/sotruss-lib.c
 create mode 100644 sysdeps/arc/start.S
 create mode 100644 sysdeps/arc/tst-audit.h

Comments

Adhemerval Zanella May 27, 2020, 7:05 p.m. UTC | #1
On 22/04/2020 22:41, Vineet Gupta via Libc-alpha wrote:
> Code for C runtime startup and dynamic loading including PLT layout.
> 
> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

As prior patch we do not use DCO, but rather copyright assignment.

Looks ok in general, with some comments below.


> ---
>  sysdeps/arc/bits/link.h   |  52 ++++++
>  sysdeps/arc/dl-machine.h  | 340 ++++++++++++++++++++++++++++++++++++++
>  sysdeps/arc/entry.h       |   5 +
>  sysdeps/arc/ldsodefs.h    |  43 +++++
>  sysdeps/arc/sotruss-lib.c |  51 ++++++
>  sysdeps/arc/start.S       |  74 +++++++++
>  sysdeps/arc/tst-audit.h   |  23 +++
>  7 files changed, 588 insertions(+)
>  create mode 100644 sysdeps/arc/bits/link.h
>  create mode 100644 sysdeps/arc/dl-machine.h
>  create mode 100644 sysdeps/arc/entry.h
>  create mode 100644 sysdeps/arc/ldsodefs.h
>  create mode 100644 sysdeps/arc/sotruss-lib.c
>  create mode 100644 sysdeps/arc/start.S
>  create mode 100644 sysdeps/arc/tst-audit.h
> 
> diff --git a/sysdeps/arc/bits/link.h b/sysdeps/arc/bits/link.h
> new file mode 100644
> index 000000000000..0acbc1349e08
> --- /dev/null
> +++ b/sysdeps/arc/bits/link.h
> @@ -0,0 +1,52 @@
> +/* Machine-specific declarations for dynamic linker interface, ARC version.
> +   Copyright (C) 2009-2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#ifndef	_LINK_H
> +# error "Never include <bits/link.h> directly; use <link.h> instead."
> +#endif
> +
> +/* Registers for entry into PLT on ARC.  */
> +typedef struct La_arc_regs
> +{
> +  uint32_t lr_reg[8]; /* r0 through r7 (upto 8 args).  */
> +} La_arc_regs;
> +
> +/* Return values for calls from PLT on ARC.  */
> +typedef struct La_arc_retval
> +{
> +  /* For ARCv2, a 64-bit integer return value can use 2 regs.  */
> +  uint32_t lrv_reg[2];
> +} La_arc_retval;
> +
> +__BEGIN_DECLS
> +
> +extern ElfW(Addr) la_arc_gnu_pltenter (ElfW(Sym) *__sym, unsigned int __ndx,
> +					 uintptr_t *__refcook,
> +					 uintptr_t *__defcook,
> +					 La_arc_regs *__regs,
> +					 unsigned int *__flags,
> +					 const char *__symname,
> +					 long int *__framesizep);
> +extern unsigned int la_arc_gnu_pltexit (ElfW(Sym) *__sym, unsigned int __ndx,
> +					  uintptr_t *__refcook,
> +					  uintptr_t *__defcook,
> +					  const La_arc_regs *__inregs,
> +					  La_arc_retval *__outregs,
> +					  const char *symname);
> +
> +__END_DECLS

Ok.

> diff --git a/sysdeps/arc/dl-machine.h b/sysdeps/arc/dl-machine.h
> new file mode 100644
> index 000000000000..ebda3e21b511
> --- /dev/null
> +++ b/sysdeps/arc/dl-machine.h
> @@ -0,0 +1,340 @@
> +/* Machine-dependent ELF dynamic relocation inline functions.  ARC version.
> +   Copyright (C) 1995-2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#ifndef dl_machine_h
> +#define dl_machine_h
> +
> +#define ELF_MACHINE_NAME "arc"
> +
> +#include <entry.h>
> +
> +#ifndef ENTRY_POINT
> +# error ENTRY_POINT needs to be defined for ARC
> +#endif
> +
> +#include <string.h>
> +#include <link.h>
> +#include <dl-tls.h>
> +
> +/* Dynamic Linking ABI for ARCv2 ISA.
> +
> +                        PLT
> +          --------------------------------	<---- DT_PLTGOT
> +          |  ld r11, [pcl, off-to-GOT[1] |  0
> +          |                              |  4
> +   plt0   |  ld r10, [pcl, off-to-GOT[2] |  8
> +          |                              | 12
> +          |  j [r10]                     | 16
> +          --------------------------------
> +          |    Base address of GOT       | 20
> +          --------------------------------
> +          |  ld r12, [pcl, off-to-GOT[3] | 24
> +   plt1   |                              |
> +          |  j.d    [r12]                | 32
> +          |  mov    r12, pcl             | 36
> +          --------------------------------
> +          |                              | 40
> +          ~                              ~
> +          ~                              ~
> +          |                              |
> +          --------------------------------
> +
> +               .got
> +          --------------
> +          |    [0]     |
> +          |    ...     |  Runtime address for data symbols
> +          |    [n]     |
> +          --------------
> +
> +            .got.plt
> +          --------------
> +          |    [0]     |  Build address of .dynamic
> +          --------------
> +          |    [1]     |  Module info - setup by ld.so
> +          --------------
> +          |    [2]     |  resolver entry point
> +          --------------
> +          |    [3]     |
> +          |    ...     |  Runtime address for function symbols
> +          |    [f]     |
> +          --------------
> +
> +   For ARCompact, the PLT is 12 bytes due to short instructions
> +
> +          --------------------------------
> +          |  ld r12, [pcl, off-to-GOT[3] | 24   (12 bytes each)
> +   plt1   |                              |
> +          |  j_s.d  [r12]                | 32
> +          |  mov_s  r12, pcl             | 34
> +          --------------------------------
> +          |                              | 36  */
> +
> +/* Return nonzero iff ELF header is compatible with the running host.  */
> +static inline int
> +elf_machine_matches_host (const Elf32_Ehdr *ehdr)
> +{
> +  return (ehdr->e_machine == EM_ARCV2		 /* ARC HS.  */
> +	  || ehdr->e_machine == EM_ARC_COMPACT); /* ARC 700.  */
> +}
> +
> +/* Get build time address of .dynamic as setup in GOT[0]
> +   This is called very early in _dl_start so it has not been relocated to
> +   runtime value.  */
> +static inline ElfW(Addr)
> +elf_machine_dynamic (void)
> +{
> +  extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden;
> +  return _GLOBAL_OFFSET_TABLE_[0];
> +}
> +
> +
> +/* Return the run-time load address of the shared object.  */
> +static inline ElfW(Addr)
> +elf_machine_load_address (void)
> +{
> +  ElfW(Addr) build_addr, run_addr;
> +
> +  /* For build address, below generates
> +     ld  r0, [pcl, _GLOBAL_OFFSET_TABLE_@pcl].  */
> +  build_addr = elf_machine_dynamic ();
> +  __asm__ ("add %0, pcl, _DYNAMIC@pcl	\n" : "=r" (run_addr));
> +
> +  return run_addr - build_addr;
> +}

Why does it need an inline asm here?

> +
> +/* Set up the loaded object described by L so its unrelocated PLT
> +   entries will jump to the on-demand fixup code in dl-runtime.c.  */
> +
> +static inline int
> +__attribute__ ((always_inline))
> +elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
> +{
> +  extern void _dl_runtime_resolve (Elf32_Word);
> +
> +  if (l->l_info[DT_JMPREL] && lazy)
> +    {
> +      /* On ARC DT_PLTGOT point to .plt whose 5th word (after the PLT header)
> +         contains the address of .got.  */
> +      ElfW(Addr) *plt_base = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
> +      ElfW(Addr) *got = (ElfW(Addr) *) (plt_base[5] + l->l_addr);
> +
> +      got[1] = (ElfW(Addr)) l;	/* Identify this shared object.  */
> +
> +      /* This function will get called to fix up the GOT entry indicated by
> +	 the offset on the stack, and then jump to the resolved address.  */
> +      got[2] = (ElfW(Addr)) &_dl_runtime_resolve;
> +    }
> +
> +  return lazy;
> +}
> +
> +/* What this code does:
> +    -ldso starts execution here when kernel returns from execve
> +    -calls into generic ldso entry point _dl_start
> +    -optionally adjusts argc for executable if exec passed as cmd
> +    -calls into app main with address of finaliser.  */
> +
> +#define RTLD_START asm ("\
> +.text								\n\
> +.globl __start							\n\
> +.type __start, @function					\n\
> +__start:							\n\
> +	; (1). bootstrap ld.so					\n\
> +	bl.d    _dl_start                                       \n\
> +	mov_s   r0, sp          ; pass ptr to aux vector tbl    \n\
> +	mov r13, r0		; safekeep app elf entry point	\n\
> +								\n\
> +	; (2). If ldso ran with executable as arg		\n\
> +	;      skip the extra args calc by dl_start		\n\
> +	ld_s    r1, [sp]       ; orig argc			\n\
> +	ld      r12, [pcl, _dl_skip_args@pcl]                   \n\
> +	breq	r12, 0, 1f					\n\
> +								\n\
> +	add2    sp, sp, r12    ; discard argv entries from stack\n\
> +	sub_s   r1, r1, r12    ; adjusted argc, on stack        \n\
> +	st_s    r1, [sp]                                        \n\
> +	add	r2, sp, 4					\n\
> +	ld	r3, [pcl, _dl_argv@gotpc]    ; ST doesn't support this addressing mode	\n\
> +	st	r2, [r3]					\n\
> +1:								\n\
> +	; (3). call preinit stuff				\n\
> +	ld	r0, [pcl, _rtld_local@pcl]			\n\
> +	add	r2, sp, 4	; argv				\n\
> +	add2	r3, r2, r1					\n\
> +	add	r3, r3, 4	; env				\n\
> +	bl	_dl_init@plt					\n\
> +								\n\
> +	; (4) call app elf entry point				\n\
> +	add     r0, pcl, _dl_fini@pcl				\n\
> +	j	[r13]						\n\
> +								\n\
> +	.size  __start,.-__start                                \n\
> +	.previous                                               \n\
> +");
> +
> +/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
> +   PLT entries should not be allowed to define the value.
> +   ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
> +   of the main executable's symbols, as for a COPY reloc.  */
> +#define elf_machine_type_class(type)				\
> +  ((((type) == R_ARC_JUMP_SLOT					\
> +     || (type) == R_ARC_TLS_DTPMOD				\
> +     || (type) == R_ARC_TLS_DTPOFF				\
> +     || (type) == R_ARC_TLS_TPOFF) * ELF_RTYPE_CLASS_PLT)	\
> +   | (((type) == R_ARC_COPY) * ELF_RTYPE_CLASS_COPY))
> +
> +/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
> +#define ELF_MACHINE_JMP_SLOT  R_ARC_JUMP_SLOT
> +
> +/* ARC uses Elf32_Rela relocations.  */
> +#define ELF_MACHINE_NO_REL 1
> +#define ELF_MACHINE_NO_RELA 0
> +
> +/* Fixup a PLT entry to bounce directly to the function at VALUE.  */
> +
> +static inline ElfW(Addr)
> +elf_machine_fixup_plt (struct link_map *map, lookup_t t,
> +		       const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
> +		       const Elf32_Rela *reloc,
> +		       ElfW(Addr) *reloc_addr, ElfW(Addr) value)
> +{
> +  return *reloc_addr = value;
> +}
> +
> +/* Return the final value of a plt relocation.  */
> +static inline ElfW(Addr)
> +elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
> +                       ElfW(Addr) value)
> +{
> +  return value;
> +}
> +
> +/* Names of the architecture-specific auditing callback functions.  */
> +#define ARCH_LA_PLTENTER arc_gnu_pltenter
> +#define ARCH_LA_PLTEXIT arc_gnu_pltexit
> +
> +#endif /* dl_machine_h */
> +
> +#ifdef RESOLVE_MAP
> +
> +auto inline void
> +__attribute__ ((always_inline))
> +elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
> +                  const ElfW(Sym) *sym, const struct r_found_version *version,
> +                  void *const reloc_addr_arg, int skip_ifunc)
> +{
> +  ElfW(Addr) *const reloc_addr = reloc_addr_arg;
> +  const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
> +
> +  if (__glibc_unlikely (r_type == R_ARC_RELATIVE))
> +    *reloc_addr += map->l_addr;
> +  else if (__glibc_unlikely (r_type == R_ARC_NONE))
> +    return;
> +  else
> +    {
> +      const ElfW(Sym) *const refsym = sym;
> +      struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
> +      ElfW(Addr) value = SYMBOL_ADDRESS (sym_map, sym, true);
> +
> +      switch (r_type)
> +	{
> +        case R_ARC_COPY:
> +	  if (__glibc_unlikely (sym == NULL))
> +            /* This can happen in trace mode if an object could not be
> +               found.  */
> +            break;
> +
> +	  size_t size = sym->st_size;
> +          if (__glibc_unlikely (size != refsym->st_size))
> +            {
> +	    const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
> +	    if (sym->st_size > refsym->st_size)
> +	      size = refsym->st_size;
> +	    if (sym->st_size > refsym->st_size || GLRO(dl_verbose))
> +	      _dl_error_printf ("\
> +  %s: Symbol `%s' has different size in shared object, consider re-linking\n",
> +				rtld_progname ?: "<program name unknown>",
> +				strtab + refsym->st_name);
> +            }
> +
> +          memcpy (reloc_addr_arg, (void *) value, size);
> +          break;
> +	case R_ARC_GLOB_DAT:
> +	case R_ARC_JUMP_SLOT:
> +            *reloc_addr = value;
> +          break;
> +        case R_ARC_TLS_DTPMOD:
> +          if (sym_map != NULL)
> +            /* Get the information from the link map returned by the
> +               resolv function.  */
> +            *reloc_addr = sym_map->l_tls_modid;
> +          break;
> +
> +        case R_ARC_TLS_DTPOFF:
> +          if (sym != NULL)
> +            /* Offset set by the linker in the GOT entry would be overwritten
> +               by dynamic loader instead of added to the symbol location.
> +               Other target have the same approach on DTPOFF relocs.  */
> +            *reloc_addr += sym->st_value;
> +          break;
> +
> +        case R_ARC_TLS_TPOFF:
> +          if (sym != NULL)
> +            {
> +              CHECK_STATIC_TLS (map, sym_map);
> +              *reloc_addr = sym_map->l_tls_offset + sym->st_value + reloc->r_addend;
> +            }
> +          break;
> +        case R_ARC_32:
> +          *reloc_addr += value + reloc->r_addend;
> +          break;
> +
> +        case R_ARC_PC32:
> +          *reloc_addr += value + reloc->r_addend - (unsigned long int) reloc_addr;
> +          break;
> +
> +	default:
> +          _dl_reloc_bad_type (map, r_type, 0);
> +          break;
> +	}
> +    }
> +}
> +
> +auto inline void

Do we still need to use 'auto' keyword here? Same for other uses.

> +__attribute__ ((always_inline))
> +elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
> +			   void *const reloc_addr_arg)
> +{
> +  ElfW(Addr) *const reloc_addr = reloc_addr_arg;
> +  *reloc_addr += l_addr;
> +}
> +
> +auto inline void
> +__attribute__ ((always_inline))
> +elf_machine_lazy_rel (struct link_map *map,
> +		      ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
> +		      int skip_ifunc)
> +{
> +  ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
> +  if (ELF32_R_TYPE (reloc->r_info) == R_ARC_JUMP_SLOT)
> +    *reloc_addr += l_addr;
> +  else
> +    _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
> +}
> +
> +#endif /* RESOLVE_MAP */

Ok.

> diff --git a/sysdeps/arc/entry.h b/sysdeps/arc/entry.h
> new file mode 100644
> index 000000000000..adb01d981afd
> --- /dev/null
> +++ b/sysdeps/arc/entry.h
> @@ -0,0 +1,5 @@
> +#ifndef __ASSEMBLY__
> +extern void __start (void) attribute_hidden;
> +#endif
> +
> +#define ENTRY_POINT __start

Ok.  Why ARC has decided to use double underscore start btw?

> diff --git a/sysdeps/arc/ldsodefs.h b/sysdeps/arc/ldsodefs.h
> new file mode 100644
> index 000000000000..c217a9d84b80
> --- /dev/null
> +++ b/sysdeps/arc/ldsodefs.h
> @@ -0,0 +1,43 @@
> +/* Run-time dynamic linker data structures for loaded ELF shared objects.
> +   Copyright (C) 2000-2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#ifndef _ARC_LDSODEFS_H
> +#define _ARC_LDSODEFS_H 1
> +
> +#include <elf.h>
> +
> +struct La_arc_regs;
> +struct La_arc_retval;
> +
> +#define ARCH_PLTENTER_MEMBERS						\
> +    ElfW(Addr) (*arc_gnu_pltenter) (ElfW(Sym) *, unsigned int,	\
> +				      uintptr_t *, uintptr_t *,		\
> +				      const struct La_arc_regs *,	\
> +				      unsigned int *, const char *,	\
> +				      long int *);
> +
> +#define ARCH_PLTEXIT_MEMBERS						\
> +    unsigned int (*arc_gnu_pltexit) (ElfW(Sym) *, unsigned int,	\
> +				       uintptr_t *, uintptr_t *,	\
> +				       const struct La_arc_regs *,	\
> +				       struct La_arc_retval *,	\
> +				       const char *);
> +
> +#include_next <ldsodefs.h>
> +
> +#endif

Ok.

> diff --git a/sysdeps/arc/sotruss-lib.c b/sysdeps/arc/sotruss-lib.c
> new file mode 100644
> index 000000000000..3253d610c5e0
> --- /dev/null
> +++ b/sysdeps/arc/sotruss-lib.c
> @@ -0,0 +1,51 @@
> +/* Override generic sotruss-lib.c to define actual functions for ARC.
> +   Copyright (C) 2017-2020 Free Software Foundation, Inc.
> +
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define HAVE_ARCH_PLTENTER
> +#define HAVE_ARCH_PLTEXIT
> +
> +#include <elf/sotruss-lib.c>
> +
> +ElfW(Addr)
> +la_arc_gnu_pltenter (ElfW(Sym) *sym __attribute__ ((unused)),
> +		       unsigned int ndx __attribute__ ((unused)),
> +		       uintptr_t *refcook, uintptr_t *defcook,
> +		       La_arc_regs *regs, unsigned int *flags,
> +		       const char *symname, long int *framesizep)
> +{
> +  print_enter (refcook, defcook, symname,
> +	       regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2],
> +	       *flags);
> +
> +  /* No need to copy anything, we will not need the parameters in any case.  */
> +  *framesizep = 0;
> +
> +  return sym->st_value;
> +}
> +
> +unsigned int
> +la_arc_gnu_pltexit (ElfW(Sym) *sym, unsigned int ndx, uintptr_t *refcook,
> +		      uintptr_t *defcook,
> +		      const struct La_arc_regs *inregs,
> +		      struct La_arc_retval *outregs, const char *symname)
> +{
> +  print_exit (refcook, defcook, symname, outregs->lrv_reg[0]);
> +
> +  return 0;
> +}

Ok.

> diff --git a/sysdeps/arc/start.S b/sysdeps/arc/start.S
> new file mode 100644
> index 000000000000..25e43d71da9e
> --- /dev/null
> +++ b/sysdeps/arc/start.S
> @@ -0,0 +1,74 @@
> +/* Startup code for ARC.
> +   Copyright (C) 1995-2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define __ASSEMBLY__ 1
> +#include <entry.h>
> +#include <sysdep.h>
> +
> +#ifndef ENTRY_POINT
> +# error ENTRY_POINT needs to be defined for ARC
> +#endif
> +
> +/* When we enter this piece of code, the program stack looks like this:
> +        argc            argument counter (integer)
> +        argv[0]         program name (pointer)
> +        argv[1...N]     program args (pointers)
> +        argv[argc-1]    end of args (integer)
> +	NULL
> +        env[0...N]      environment variables (pointers)
> +        NULL.  */
> +
> +ENTRY (ENTRY_POINT)
> +
> +	/* Needed to make gdb backtraces stop here.  */
> +	.cfi_label .Ldummy
> +	cfi_undefined (blink)
> +
> +	mov	fp, 0
> +	ld_s	r1, [sp]	; argc
> +
> +	mov_s	r5, r0		; rltd_fini
> +	add_s	r2, sp, 4	; argv
> +	and	sp, sp, -8
> +	mov	r6, sp
> +
> +	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end).  */
> +
> +#ifdef SHARED
> +	ld	r0, [pcl, @main@gotpc]
> +	ld	r3, [pcl, @__libc_csu_init@gotpc]
> +	ld	r4, [pcl, @__libc_csu_fini@gotpc]
> +	bl	__libc_start_main@plt
> +#else
> +	mov_s	r0, main
> +	mov_s	r3, __libc_csu_init
> +	mov	r4, __libc_csu_fini
> +	bl	__libc_start_main
> +#endif
> +
> +	/* Should never get here.  */
> +	flag    1
> +END (ENTRY_POINT)
> +
> +/* Define a symbol for the first piece of initialized data.  */
> +	.data
> +	.globl __data_start
> +__data_start:
> +	.long 0
> +	.weak data_start
> +	data_start = __data_start

Ok.

> diff --git a/sysdeps/arc/tst-audit.h b/sysdeps/arc/tst-audit.h
> new file mode 100644
> index 000000000000..10a20c49c00c
> --- /dev/null
> +++ b/sysdeps/arc/tst-audit.h
> @@ -0,0 +1,23 @@
> +/* Definitions for testing PLT entry/exit auditing.  ARC version.
> +   Copyright (C) 2009-2020 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library.  If not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define pltenter la_arc_gnu_pltenter
> +#define pltexit la_arc_gnu_pltexit
> +#define La_regs La_arc_regs
> +#define La_retval La_arc_retval
> +#define int_retval lrv_reg[0]
> 

Ok.
Vineet Gupta May 28, 2020, 1:14 a.m. UTC | #2
On 5/27/20 12:05 PM, Adhemerval Zanella via Libc-alpha wrote:
> 
> 
> On 22/04/2020 22:41, Vineet Gupta via Libc-alpha wrote:
>> Code for C runtime startup and dynamic loading including PLT layout.
>>
>> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
> 
> As prior patch we do not use DCO, but rather copyright assignment.
> 
> Looks ok in general, with some comments below.
> 
> 

>> +
>> +
>> +/* Return the run-time load address of the shared object.  */
>> +static inline ElfW(Addr)
>> +elf_machine_load_address (void)
>> +{
>> +  ElfW(Addr) build_addr, run_addr;
>> +
>> +  /* For build address, below generates
>> +     ld  r0, [pcl, _GLOBAL_OFFSET_TABLE_@pcl].  */
>> +  build_addr = elf_machine_dynamic ();
>> +  __asm__ ("add %0, pcl, _DYNAMIC@pcl	\n" : "=r" (run_addr));
>> +
>> +  return run_addr - build_addr;
>> +}
> 
> Why does it need an inline asm here?

PCL is a pseudo register and we use the @pcl assembler syntax to get runtime
address of DYNAMIC section. Last I checked the aarch64 style reference to _DYNAMIC
in "C" was not generating the right code.

>> +auto inline void
> 
> Do we still need to use 'auto' keyword here? Same for other uses.
Copy-paste thinko, I'll remove it.


>> diff --git a/sysdeps/arc/entry.h b/sysdeps/arc/entry.h
>> new file mode 100644
>> index 000000000000..adb01d981afd
>> --- /dev/null
>> +++ b/sysdeps/arc/entry.h
>> @@ -0,0 +1,5 @@
>> +#ifndef __ASSEMBLY__
>> +extern void __start (void) attribute_hidden;
>> +#endif
>> +
>> +#define ENTRY_POINT __start
> 
> Ok.  Why ARC has decided to use double underscore start btw?

Historically the linker scripts have had __start as entry point. Do note that we
use the same linker scripts for other libs etc so changing them would be very painful.
diff mbox series

Patch

diff --git a/sysdeps/arc/bits/link.h b/sysdeps/arc/bits/link.h
new file mode 100644
index 000000000000..0acbc1349e08
--- /dev/null
+++ b/sysdeps/arc/bits/link.h
@@ -0,0 +1,52 @@ 
+/* Machine-specific declarations for dynamic linker interface, ARC version.
+   Copyright (C) 2009-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef	_LINK_H
+# error "Never include <bits/link.h> directly; use <link.h> instead."
+#endif
+
+/* Registers for entry into PLT on ARC.  */
+typedef struct La_arc_regs
+{
+  uint32_t lr_reg[8]; /* r0 through r7 (upto 8 args).  */
+} La_arc_regs;
+
+/* Return values for calls from PLT on ARC.  */
+typedef struct La_arc_retval
+{
+  /* For ARCv2, a 64-bit integer return value can use 2 regs.  */
+  uint32_t lrv_reg[2];
+} La_arc_retval;
+
+__BEGIN_DECLS
+
+extern ElfW(Addr) la_arc_gnu_pltenter (ElfW(Sym) *__sym, unsigned int __ndx,
+					 uintptr_t *__refcook,
+					 uintptr_t *__defcook,
+					 La_arc_regs *__regs,
+					 unsigned int *__flags,
+					 const char *__symname,
+					 long int *__framesizep);
+extern unsigned int la_arc_gnu_pltexit (ElfW(Sym) *__sym, unsigned int __ndx,
+					  uintptr_t *__refcook,
+					  uintptr_t *__defcook,
+					  const La_arc_regs *__inregs,
+					  La_arc_retval *__outregs,
+					  const char *symname);
+
+__END_DECLS
diff --git a/sysdeps/arc/dl-machine.h b/sysdeps/arc/dl-machine.h
new file mode 100644
index 000000000000..ebda3e21b511
--- /dev/null
+++ b/sysdeps/arc/dl-machine.h
@@ -0,0 +1,340 @@ 
+/* Machine-dependent ELF dynamic relocation inline functions.  ARC version.
+   Copyright (C) 1995-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef dl_machine_h
+#define dl_machine_h
+
+#define ELF_MACHINE_NAME "arc"
+
+#include <entry.h>
+
+#ifndef ENTRY_POINT
+# error ENTRY_POINT needs to be defined for ARC
+#endif
+
+#include <string.h>
+#include <link.h>
+#include <dl-tls.h>
+
+/* Dynamic Linking ABI for ARCv2 ISA.
+
+                        PLT
+          --------------------------------	<---- DT_PLTGOT
+          |  ld r11, [pcl, off-to-GOT[1] |  0
+          |                              |  4
+   plt0   |  ld r10, [pcl, off-to-GOT[2] |  8
+          |                              | 12
+          |  j [r10]                     | 16
+          --------------------------------
+          |    Base address of GOT       | 20
+          --------------------------------
+          |  ld r12, [pcl, off-to-GOT[3] | 24
+   plt1   |                              |
+          |  j.d    [r12]                | 32
+          |  mov    r12, pcl             | 36
+          --------------------------------
+          |                              | 40
+          ~                              ~
+          ~                              ~
+          |                              |
+          --------------------------------
+
+               .got
+          --------------
+          |    [0]     |
+          |    ...     |  Runtime address for data symbols
+          |    [n]     |
+          --------------
+
+            .got.plt
+          --------------
+          |    [0]     |  Build address of .dynamic
+          --------------
+          |    [1]     |  Module info - setup by ld.so
+          --------------
+          |    [2]     |  resolver entry point
+          --------------
+          |    [3]     |
+          |    ...     |  Runtime address for function symbols
+          |    [f]     |
+          --------------
+
+   For ARCompact, the PLT is 12 bytes due to short instructions
+
+          --------------------------------
+          |  ld r12, [pcl, off-to-GOT[3] | 24   (12 bytes each)
+   plt1   |                              |
+          |  j_s.d  [r12]                | 32
+          |  mov_s  r12, pcl             | 34
+          --------------------------------
+          |                              | 36  */
+
+/* Return nonzero iff ELF header is compatible with the running host.  */
+static inline int
+elf_machine_matches_host (const Elf32_Ehdr *ehdr)
+{
+  return (ehdr->e_machine == EM_ARCV2		 /* ARC HS.  */
+	  || ehdr->e_machine == EM_ARC_COMPACT); /* ARC 700.  */
+}
+
+/* Get build time address of .dynamic as setup in GOT[0]
+   This is called very early in _dl_start so it has not been relocated to
+   runtime value.  */
+static inline ElfW(Addr)
+elf_machine_dynamic (void)
+{
+  extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden;
+  return _GLOBAL_OFFSET_TABLE_[0];
+}
+
+
+/* Return the run-time load address of the shared object.  */
+static inline ElfW(Addr)
+elf_machine_load_address (void)
+{
+  ElfW(Addr) build_addr, run_addr;
+
+  /* For build address, below generates
+     ld  r0, [pcl, _GLOBAL_OFFSET_TABLE_@pcl].  */
+  build_addr = elf_machine_dynamic ();
+  __asm__ ("add %0, pcl, _DYNAMIC@pcl	\n" : "=r" (run_addr));
+
+  return run_addr - build_addr;
+}
+
+/* Set up the loaded object described by L so its unrelocated PLT
+   entries will jump to the on-demand fixup code in dl-runtime.c.  */
+
+static inline int
+__attribute__ ((always_inline))
+elf_machine_runtime_setup (struct link_map *l, int lazy, int profile)
+{
+  extern void _dl_runtime_resolve (Elf32_Word);
+
+  if (l->l_info[DT_JMPREL] && lazy)
+    {
+      /* On ARC DT_PLTGOT point to .plt whose 5th word (after the PLT header)
+         contains the address of .got.  */
+      ElfW(Addr) *plt_base = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
+      ElfW(Addr) *got = (ElfW(Addr) *) (plt_base[5] + l->l_addr);
+
+      got[1] = (ElfW(Addr)) l;	/* Identify this shared object.  */
+
+      /* This function will get called to fix up the GOT entry indicated by
+	 the offset on the stack, and then jump to the resolved address.  */
+      got[2] = (ElfW(Addr)) &_dl_runtime_resolve;
+    }
+
+  return lazy;
+}
+
+/* What this code does:
+    -ldso starts execution here when kernel returns from execve
+    -calls into generic ldso entry point _dl_start
+    -optionally adjusts argc for executable if exec passed as cmd
+    -calls into app main with address of finaliser.  */
+
+#define RTLD_START asm ("\
+.text								\n\
+.globl __start							\n\
+.type __start, @function					\n\
+__start:							\n\
+	; (1). bootstrap ld.so					\n\
+	bl.d    _dl_start                                       \n\
+	mov_s   r0, sp          ; pass ptr to aux vector tbl    \n\
+	mov r13, r0		; safekeep app elf entry point	\n\
+								\n\
+	; (2). If ldso ran with executable as arg		\n\
+	;      skip the extra args calc by dl_start		\n\
+	ld_s    r1, [sp]       ; orig argc			\n\
+	ld      r12, [pcl, _dl_skip_args@pcl]                   \n\
+	breq	r12, 0, 1f					\n\
+								\n\
+	add2    sp, sp, r12    ; discard argv entries from stack\n\
+	sub_s   r1, r1, r12    ; adjusted argc, on stack        \n\
+	st_s    r1, [sp]                                        \n\
+	add	r2, sp, 4					\n\
+	ld	r3, [pcl, _dl_argv@gotpc]    ; ST doesn't support this addressing mode	\n\
+	st	r2, [r3]					\n\
+1:								\n\
+	; (3). call preinit stuff				\n\
+	ld	r0, [pcl, _rtld_local@pcl]			\n\
+	add	r2, sp, 4	; argv				\n\
+	add2	r3, r2, r1					\n\
+	add	r3, r3, 4	; env				\n\
+	bl	_dl_init@plt					\n\
+								\n\
+	; (4) call app elf entry point				\n\
+	add     r0, pcl, _dl_fini@pcl				\n\
+	j	[r13]						\n\
+								\n\
+	.size  __start,.-__start                                \n\
+	.previous                                               \n\
+");
+
+/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry, so
+   PLT entries should not be allowed to define the value.
+   ELF_RTYPE_CLASS_NOCOPY iff TYPE should not be allowed to resolve to one
+   of the main executable's symbols, as for a COPY reloc.  */
+#define elf_machine_type_class(type)				\
+  ((((type) == R_ARC_JUMP_SLOT					\
+     || (type) == R_ARC_TLS_DTPMOD				\
+     || (type) == R_ARC_TLS_DTPOFF				\
+     || (type) == R_ARC_TLS_TPOFF) * ELF_RTYPE_CLASS_PLT)	\
+   | (((type) == R_ARC_COPY) * ELF_RTYPE_CLASS_COPY))
+
+/* A reloc type used for ld.so cmdline arg lookups to reject PLT entries.  */
+#define ELF_MACHINE_JMP_SLOT  R_ARC_JUMP_SLOT
+
+/* ARC uses Elf32_Rela relocations.  */
+#define ELF_MACHINE_NO_REL 1
+#define ELF_MACHINE_NO_RELA 0
+
+/* Fixup a PLT entry to bounce directly to the function at VALUE.  */
+
+static inline ElfW(Addr)
+elf_machine_fixup_plt (struct link_map *map, lookup_t t,
+		       const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
+		       const Elf32_Rela *reloc,
+		       ElfW(Addr) *reloc_addr, ElfW(Addr) value)
+{
+  return *reloc_addr = value;
+}
+
+/* Return the final value of a plt relocation.  */
+static inline ElfW(Addr)
+elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
+                       ElfW(Addr) value)
+{
+  return value;
+}
+
+/* Names of the architecture-specific auditing callback functions.  */
+#define ARCH_LA_PLTENTER arc_gnu_pltenter
+#define ARCH_LA_PLTEXIT arc_gnu_pltexit
+
+#endif /* dl_machine_h */
+
+#ifdef RESOLVE_MAP
+
+auto inline void
+__attribute__ ((always_inline))
+elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
+                  const ElfW(Sym) *sym, const struct r_found_version *version,
+                  void *const reloc_addr_arg, int skip_ifunc)
+{
+  ElfW(Addr) *const reloc_addr = reloc_addr_arg;
+  const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
+
+  if (__glibc_unlikely (r_type == R_ARC_RELATIVE))
+    *reloc_addr += map->l_addr;
+  else if (__glibc_unlikely (r_type == R_ARC_NONE))
+    return;
+  else
+    {
+      const ElfW(Sym) *const refsym = sym;
+      struct link_map *sym_map = RESOLVE_MAP (&sym, version, r_type);
+      ElfW(Addr) value = SYMBOL_ADDRESS (sym_map, sym, true);
+
+      switch (r_type)
+	{
+        case R_ARC_COPY:
+	  if (__glibc_unlikely (sym == NULL))
+            /* This can happen in trace mode if an object could not be
+               found.  */
+            break;
+
+	  size_t size = sym->st_size;
+          if (__glibc_unlikely (size != refsym->st_size))
+            {
+	    const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
+	    if (sym->st_size > refsym->st_size)
+	      size = refsym->st_size;
+	    if (sym->st_size > refsym->st_size || GLRO(dl_verbose))
+	      _dl_error_printf ("\
+  %s: Symbol `%s' has different size in shared object, consider re-linking\n",
+				rtld_progname ?: "<program name unknown>",
+				strtab + refsym->st_name);
+            }
+
+          memcpy (reloc_addr_arg, (void *) value, size);
+          break;
+	case R_ARC_GLOB_DAT:
+	case R_ARC_JUMP_SLOT:
+            *reloc_addr = value;
+          break;
+        case R_ARC_TLS_DTPMOD:
+          if (sym_map != NULL)
+            /* Get the information from the link map returned by the
+               resolv function.  */
+            *reloc_addr = sym_map->l_tls_modid;
+          break;
+
+        case R_ARC_TLS_DTPOFF:
+          if (sym != NULL)
+            /* Offset set by the linker in the GOT entry would be overwritten
+               by dynamic loader instead of added to the symbol location.
+               Other target have the same approach on DTPOFF relocs.  */
+            *reloc_addr += sym->st_value;
+          break;
+
+        case R_ARC_TLS_TPOFF:
+          if (sym != NULL)
+            {
+              CHECK_STATIC_TLS (map, sym_map);
+              *reloc_addr = sym_map->l_tls_offset + sym->st_value + reloc->r_addend;
+            }
+          break;
+        case R_ARC_32:
+          *reloc_addr += value + reloc->r_addend;
+          break;
+
+        case R_ARC_PC32:
+          *reloc_addr += value + reloc->r_addend - (unsigned long int) reloc_addr;
+          break;
+
+	default:
+          _dl_reloc_bad_type (map, r_type, 0);
+          break;
+	}
+    }
+}
+
+auto inline void
+__attribute__ ((always_inline))
+elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
+			   void *const reloc_addr_arg)
+{
+  ElfW(Addr) *const reloc_addr = reloc_addr_arg;
+  *reloc_addr += l_addr;
+}
+
+auto inline void
+__attribute__ ((always_inline))
+elf_machine_lazy_rel (struct link_map *map,
+		      ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
+		      int skip_ifunc)
+{
+  ElfW(Addr) *const reloc_addr = (void *) (l_addr + reloc->r_offset);
+  if (ELF32_R_TYPE (reloc->r_info) == R_ARC_JUMP_SLOT)
+    *reloc_addr += l_addr;
+  else
+    _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1);
+}
+
+#endif /* RESOLVE_MAP */
diff --git a/sysdeps/arc/entry.h b/sysdeps/arc/entry.h
new file mode 100644
index 000000000000..adb01d981afd
--- /dev/null
+++ b/sysdeps/arc/entry.h
@@ -0,0 +1,5 @@ 
+#ifndef __ASSEMBLY__
+extern void __start (void) attribute_hidden;
+#endif
+
+#define ENTRY_POINT __start
diff --git a/sysdeps/arc/ldsodefs.h b/sysdeps/arc/ldsodefs.h
new file mode 100644
index 000000000000..c217a9d84b80
--- /dev/null
+++ b/sysdeps/arc/ldsodefs.h
@@ -0,0 +1,43 @@ 
+/* Run-time dynamic linker data structures for loaded ELF shared objects.
+   Copyright (C) 2000-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _ARC_LDSODEFS_H
+#define _ARC_LDSODEFS_H 1
+
+#include <elf.h>
+
+struct La_arc_regs;
+struct La_arc_retval;
+
+#define ARCH_PLTENTER_MEMBERS						\
+    ElfW(Addr) (*arc_gnu_pltenter) (ElfW(Sym) *, unsigned int,	\
+				      uintptr_t *, uintptr_t *,		\
+				      const struct La_arc_regs *,	\
+				      unsigned int *, const char *,	\
+				      long int *);
+
+#define ARCH_PLTEXIT_MEMBERS						\
+    unsigned int (*arc_gnu_pltexit) (ElfW(Sym) *, unsigned int,	\
+				       uintptr_t *, uintptr_t *,	\
+				       const struct La_arc_regs *,	\
+				       struct La_arc_retval *,	\
+				       const char *);
+
+#include_next <ldsodefs.h>
+
+#endif
diff --git a/sysdeps/arc/sotruss-lib.c b/sysdeps/arc/sotruss-lib.c
new file mode 100644
index 000000000000..3253d610c5e0
--- /dev/null
+++ b/sysdeps/arc/sotruss-lib.c
@@ -0,0 +1,51 @@ 
+/* Override generic sotruss-lib.c to define actual functions for ARC.
+   Copyright (C) 2017-2020 Free Software Foundation, Inc.
+
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#define HAVE_ARCH_PLTENTER
+#define HAVE_ARCH_PLTEXIT
+
+#include <elf/sotruss-lib.c>
+
+ElfW(Addr)
+la_arc_gnu_pltenter (ElfW(Sym) *sym __attribute__ ((unused)),
+		       unsigned int ndx __attribute__ ((unused)),
+		       uintptr_t *refcook, uintptr_t *defcook,
+		       La_arc_regs *regs, unsigned int *flags,
+		       const char *symname, long int *framesizep)
+{
+  print_enter (refcook, defcook, symname,
+	       regs->lr_reg[0], regs->lr_reg[1], regs->lr_reg[2],
+	       *flags);
+
+  /* No need to copy anything, we will not need the parameters in any case.  */
+  *framesizep = 0;
+
+  return sym->st_value;
+}
+
+unsigned int
+la_arc_gnu_pltexit (ElfW(Sym) *sym, unsigned int ndx, uintptr_t *refcook,
+		      uintptr_t *defcook,
+		      const struct La_arc_regs *inregs,
+		      struct La_arc_retval *outregs, const char *symname)
+{
+  print_exit (refcook, defcook, symname, outregs->lrv_reg[0]);
+
+  return 0;
+}
diff --git a/sysdeps/arc/start.S b/sysdeps/arc/start.S
new file mode 100644
index 000000000000..25e43d71da9e
--- /dev/null
+++ b/sysdeps/arc/start.S
@@ -0,0 +1,74 @@ 
+/* Startup code for ARC.
+   Copyright (C) 1995-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#define __ASSEMBLY__ 1
+#include <entry.h>
+#include <sysdep.h>
+
+#ifndef ENTRY_POINT
+# error ENTRY_POINT needs to be defined for ARC
+#endif
+
+/* When we enter this piece of code, the program stack looks like this:
+        argc            argument counter (integer)
+        argv[0]         program name (pointer)
+        argv[1...N]     program args (pointers)
+        argv[argc-1]    end of args (integer)
+	NULL
+        env[0...N]      environment variables (pointers)
+        NULL.  */
+
+ENTRY (ENTRY_POINT)
+
+	/* Needed to make gdb backtraces stop here.  */
+	.cfi_label .Ldummy
+	cfi_undefined (blink)
+
+	mov	fp, 0
+	ld_s	r1, [sp]	; argc
+
+	mov_s	r5, r0		; rltd_fini
+	add_s	r2, sp, 4	; argv
+	and	sp, sp, -8
+	mov	r6, sp
+
+	/* __libc_start_main (main, argc, argv, init, fini, rtld_fini, stack_end).  */
+
+#ifdef SHARED
+	ld	r0, [pcl, @main@gotpc]
+	ld	r3, [pcl, @__libc_csu_init@gotpc]
+	ld	r4, [pcl, @__libc_csu_fini@gotpc]
+	bl	__libc_start_main@plt
+#else
+	mov_s	r0, main
+	mov_s	r3, __libc_csu_init
+	mov	r4, __libc_csu_fini
+	bl	__libc_start_main
+#endif
+
+	/* Should never get here.  */
+	flag    1
+END (ENTRY_POINT)
+
+/* Define a symbol for the first piece of initialized data.  */
+	.data
+	.globl __data_start
+__data_start:
+	.long 0
+	.weak data_start
+	data_start = __data_start
diff --git a/sysdeps/arc/tst-audit.h b/sysdeps/arc/tst-audit.h
new file mode 100644
index 000000000000..10a20c49c00c
--- /dev/null
+++ b/sysdeps/arc/tst-audit.h
@@ -0,0 +1,23 @@ 
+/* Definitions for testing PLT entry/exit auditing.  ARC version.
+   Copyright (C) 2009-2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#define pltenter la_arc_gnu_pltenter
+#define pltexit la_arc_gnu_pltexit
+#define La_regs La_arc_regs
+#define La_retval La_arc_retval
+#define int_retval lrv_reg[0]