Re: [PATCH v4 04/13] or1k: startup and dynamic linking code

[Stafford Horne <shorne@gmail.com>]

On Mon, Jan 03, 2022 at 03:17:15PM -0300, Adhemerval Zanella wrote:
> 
> 
> On 29/12/2021 01:42, Stafford Horne via Libc-alpha wrote:
> > Code for C runtime startup and dynamic loading including PLT layout.
> 
> Looks good, although I can't really voucher since I don't have direct access
> to a or1k system.  Just some comments bellow and a possible fix for the inline
> asm.
> 
> LGTM with the fixed.
> 
> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Thank you.  See my comments below.

> > ---
> >  sysdeps/or1k/bits/link.h   |  54 +++++++
> >  sysdeps/or1k/dl-machine.h  | 300 +++++++++++++++++++++++++++++++++++++
> >  sysdeps/or1k/dl-start.S    |  98 ++++++++++++
> >  sysdeps/or1k/ldsodefs.h    |  40 +++++
> >  sysdeps/or1k/sotruss-lib.c |  51 +++++++
> >  sysdeps/or1k/start.S       |  99 ++++++++++++
> >  sysdeps/or1k/tst-audit.h   |  24 +++
> >  7 files changed, 666 insertions(+)
> >  create mode 100644 sysdeps/or1k/bits/link.h
> >  create mode 100644 sysdeps/or1k/dl-machine.h
> >  create mode 100644 sysdeps/or1k/dl-start.S
> >  create mode 100644 sysdeps/or1k/ldsodefs.h
> >  create mode 100644 sysdeps/or1k/sotruss-lib.c
> >  create mode 100644 sysdeps/or1k/start.S
> >  create mode 100644 sysdeps/or1k/tst-audit.h
> > 
> > diff --git a/sysdeps/or1k/bits/link.h b/sysdeps/or1k/bits/link.h
> > new file mode 100644
> > index 0000000000..f291d66269
> > --- /dev/null
> > +++ b/sysdeps/or1k/bits/link.h
> > @@ -0,0 +1,54 @@
> > +/* Declarations for dynamic linker interface. OpenRISC version.
> > +   Copyright (C) 2021 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.  */
> > +typedef struct La_or1k_regs
> > +{
> > +  uint32_t lr_reg[6]; /* Args passed in r3-r8.  */
> > +  uint32_t lr_sp;     /* Register r1.  */
> > +  uint32_t lr_lr;     /* Register r9.  */
> > +} La_or1k_regs;
> > +
> > +/* Return values for calls from PLT.  */
> > +typedef struct La_or1k_retval
> > +{
> > +  /* Up to two 32-bit registers used for a return value.  */
> > +  uint32_t lrv_reg[2];
> > +} La_or1k_retval;
> > +
> > +__BEGIN_DECLS
> > +
> > +extern ElfW(Addr) la_or1k_gnu_pltenter (ElfW(Sym) *__sym, unsigned int __ndx,
> > +					uintptr_t *__refcook,
> > +					uintptr_t *__defcook,
> > +					La_or1k_regs *__regs,
> > +					unsigned int *__flags,
> > +					const char *__symname,
> > +					long int *__framesizep);
> > +extern unsigned int la_or1k_gnu_pltexit (ElfW(Sym) *__sym, unsigned int __ndx,
> > +					 uintptr_t *__refcook,
> > +					 uintptr_t *__defcook,
> > +					 const La_or1k_regs *__inregs,
> > +					 La_or1k_retval *__outregs,
> > +					 const char *__symname);
> > +
> > +__END_DECLS
> 
> I think you can use Elf32_Addr and Elf32_Sym directly here, since or1k 
> does not have a 64-bit neither this file will be used along it.

OK.

> > diff --git a/sysdeps/or1k/dl-machine.h b/sysdeps/or1k/dl-machine.h
> > new file mode 100644
> > index 0000000000..ec4db533d2
> > --- /dev/null
> > +++ b/sysdeps/or1k/dl-machine.h
> > @@ -0,0 +1,300 @@
> > +/* Machine-dependent ELF dynamic relocation inline functions.  OpenRISC version.
> > +   Copyright (C) 2021 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 "or1k"
> > +
> > +#include <sys/cdefs.h>
> > +#include <sys/param.h>
> > +#include <tls.h>
> > +#include <dl-irel.h>
> > +#include <dl-static-tls.h>
> > +#include <dl-machine-rel.h>
> > +
> > +/* Return nonzero iff ELF header is compatible with the running host.  */
> > +static inline int __attribute__ ((unused))
> > +elf_machine_matches_host (const Elf32_Ehdr *ehdr)
> > +{
> > +  return ehdr->e_machine == EM_OPENRISC;
> > +}
> > +
> > +static inline Elf32_Addr *
> > +or1k_get_got (void)
> > +{
> > +  Elf32_Addr *got;
> > +
> > +  asm ("l.jal    0x8\n"
> > +       " l.movhi %0, gotpchi(_GLOBAL_OFFSET_TABLE_-4)\n"
> > +       "l.ori    %0, %0, gotpclo(_GLOBAL_OFFSET_TABLE_+0)\n"
> > +       "l.add    %0, %0, r9\n"
> > +       : "=r" (got) : : "r9");
> 
> 
> I think this requires a "memory" clobber.

Why would it?  This does not do any memory loads or stores.

Let me test with "memory" clobber and see what the difference is.

> > +
> > +  return got;
> > +}
> > +
> > +/* Return the link-time address of _DYNAMIC.  Conveniently, this is the
> > +   first element of the GOT.  */
> > +static inline Elf32_Addr
> > +elf_machine_dynamic (void)
> > +{
> > +  Elf32_Addr *got = or1k_get_got ();
> > +  return *got;
> > +}
> > +
> > +
> > +/* Return the run-time load address of the shared object.  */
> > +static inline Elf32_Addr
> > +elf_machine_load_address (void)
> > +{
> > +  /* Compute the difference between the runtime address of _DYNAMIC as seen
> > +     by a GOTOFF reference, and the link-time address found in the special
> > +     unrelocated first GOT entry.  */
> > +  Elf32_Addr dyn;
> > +  Elf32_Addr *got = or1k_get_got ();
> > +
> > +  asm ("l.movhi %0, gotoffhi(_DYNAMIC);"
> > +       "l.ori   %0, %0, gotofflo(_DYNAMIC);"
> > +       "l.add   %0, %0, %1;"
> > +       : "=&r"(dyn) : "r"(got));
> 
> Also here.

Same here, it does not read/write memory.  I will look into it, maybe there is
something I don't understand about "memory" clobber.

> > +
> > +  return dyn - *got;
> > +}
> > +
> > +/* Initial entry point code for the dynamic linker.  The function _dl_start
> > +   is the real entry point; it's return value is the user program's entry
> > +   point.
> > +
> > +   Code is really located in dl-start.S, just tell the linker that it
> > +   exists.  */
> > +#define RTLD_START asm (".globl _dl_start");
> > +
> > +/* ELF_RTYPE_CLASS_PLT iff TYPE describes relocation of a PLT entry or
> > +   TLS variable, so undefined references 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_OR1K_JMP_SLOT \
> > +   || (type) == R_OR1K_TLS_DTPMOD \
> > +   || (type) == R_OR1K_TLS_DTPOFF \
> > +   || (type) == R_OR1K_TLS_TPOFF) * ELF_RTYPE_CLASS_PLT \
> > +   | ((type) == R_OR1K_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_OR1K_JMP_SLOT
> > +
> > +#define ARCH_LA_PLTENTER or1k_gnu_pltenter
> > +#define ARCH_LA_PLTEXIT or1k_gnu_pltexit
> > +
> > +/* 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__ ((unused, always_inline))
> > +elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
> > +			   int lazy, int profile)
> > +{
> > +  ElfW(Addr) *pltgot;
> > +  extern void _dl_runtime_resolve (ElfW(Word));
> > +  extern void _dl_runtime_profile (ElfW(Word));
> > +
> > +  if (l->l_info[DT_JMPREL] && lazy)
> > +    {
> > +      pltgot = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
> > +
> > +      /* Fill in initial entrys of the plt */
> > +
> > +      /* Register the link_map address in the plt at pltgot[1].
> > +	 This will also be used in the resolver for accessing the
> > +	 link_map structure.  */
> > +      pltgot[1] = (ElfW(Addr)) l;
> > +
> > +      /* This function will get called to fix up the GOT entry and
> > +	 then jump to the resolved address.  */
> > +      pltgot[2] = (ElfW(Addr)) &_dl_runtime_resolve;
> > +
> > +    }
> > +
> > +  return lazy;
> > +}
> > +
> > +/* Mask identifying addresses reserved for the user program,
> > +   where the dynamic linker should not map anything.  */
> > +#define ELF_MACHINE_USER_ADDRESS_MASK   0xf8000000UL
> > +
> > +/* We define an initialization functions.  This is called very early in
> > +   _dl_sysdep_start.  */
> > +#define DL_PLATFORM_INIT dl_platform_init ()
> > +
> > +static inline void __attribute__ ((unused))
> > +dl_platform_init (void)
> > +{
> > +  if (GLRO(dl_platform) != NULL && *GLRO(dl_platform) == '\0')
> > +    /* Avoid an empty string which would disturb us.  */
> > +    GLRO(dl_platform) = NULL;
> > +}
> > +
> > +static inline ElfW(Addr)
> > +elf_machine_fixup_plt (struct link_map *map, lookup_t t,
> > +		       const ElfW(Sym) *refsym, const ElfW(Sym) *sym,
> > +		       const ElfW(Rela) *reloc,
> > +		       ElfW(Addr) *reloc_addr, ElfW(Addr) value)
> > +{
> > +  return *reloc_addr = value;
> > +}
> > +
> > +/* Return the final value of a plt relocation.  */
> > +static inline Elf32_Addr
> > +elf_machine_plt_value (struct link_map *map, const Elf32_Rela *reloc,
> > +		       Elf32_Addr value)
> > +{
> > +  return value + reloc->r_addend;
> > +}
> > +
> > +
> > +#endif /* !dl_machine_h */
> > +
> > +#ifdef RESOLVE_MAP
> > +
> > +/* Perform the relocation specified by RELOC and SYM (which is fully resolved).
> > +   MAP is the object containing the reloc.  */
> > +
> > +static inline void
> > +__attribute ((always_inline))
> > +elf_machine_rela (struct link_map *map, struct r_scope_elem *scope[],
> > +		  const ElfW(Rela) *reloc, const ElfW(Sym) *sym,
> > +		  const struct r_found_version *version,
> > +		  void *const reloc_addr_arg, int skip_ifunc)
> > +{
> > +  Elf32_Addr *const reloc_addr = reloc_addr_arg;
> > +  const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
> > +
> > +  if (__glibc_unlikely (r_type == R_OR1K_NONE))
> > +    return;
> > +  else
> > +    {
> > +# ifndef RESOLVE_CONFLICT_FIND_MAP
> > +      const Elf32_Sym *const refsym = sym;
> > +# endif
> > +      struct link_map *sym_map = RESOLVE_MAP (map, scope, &sym, version,
> > +					      r_type);
> > +      Elf32_Addr value = SYMBOL_ADDRESS (sym_map, sym, true);
> > +
> > +      if (sym != NULL
> > +	  && __glibc_unlikely (ELFW(ST_TYPE) (sym->st_info) == STT_GNU_IFUNC)
> > +	  && __glibc_likely (sym->st_shndx != SHN_UNDEF)
> > +	  && __glibc_likely (!skip_ifunc))
> > +	value = elf_ifunc_invoke (value);
> > +
> > +      switch (r_type)
> > +	{
> > +# ifndef RESOLVE_CONFLICT_FIND_MAP
> > +	  case R_OR1K_COPY:
> > +	    if (sym == NULL)
> > +	      /* This can happen in trace mode if an object could not be
> > +		 found.  */
> > +	      break;
> > +	    if (__glibc_unlikely (sym->st_size > refsym->st_size)
> > +		|| (__glibc_unlikely (sym->st_size < refsym->st_size)
> > +		  && GLRO(dl_verbose)))
> > +	    {
> > +	      const char *strtab;
> > +
> > +	      strtab = (const char *) D_PTR (map, l_info[DT_STRTAB]);
> > +	      _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,
> > +		MIN (sym->st_size, refsym->st_size));
> > +	    break;
> > +# endif /* !RESOLVE_CONFLICT_FIND_MAP */
> > +	  case R_OR1K_32:
> > +	    /* Support relocations on mis-aligned offsets.  */
> > +	    value += reloc->r_addend;
> > +	    memcpy (reloc_addr_arg, &value, 4);
> > +	    break;
> > +	  case R_OR1K_GLOB_DAT:
> > +	  case R_OR1K_JMP_SLOT:
> > +	    *reloc_addr = value + reloc->r_addend;
> > +	    break;
> > +	  case R_OR1K_TLS_DTPMOD:
> > +# ifdef RTLD_BOOTSTRAP
> > +	    /* During startup the dynamic linker is always the module
> > +	       with index 1.  */
> > +	    *reloc_addr = 1;
> > +# else
> > +	    if (sym_map != NULL)
> > +	      *reloc_addr = sym_map->l_tls_modid;
> > +# endif
> > +	    break;
> > +	  case R_OR1K_TLS_DTPOFF:
> > +# ifndef RTLD_BOOTSTRAP
> > +	    *reloc_addr = (sym == NULL ? 0 : sym->st_value) + reloc->r_addend;
> > +# endif
> > +	    break;
> > +
> > +	  case R_OR1K_TLS_TPOFF:
> > +# ifdef RTLD_BOOTSTRAP
> > +	    *reloc_addr = sym->st_value + reloc->r_addend +
> > +	      map->l_tls_offset - TLS_TCB_SIZE;
> > +# else
> > +	    if (sym_map != NULL)
> > +	      {
> > +		CHECK_STATIC_TLS (map, sym_map);
> > +		*reloc_addr = sym->st_value + reloc->r_addend +
> > +		  sym_map->l_tls_offset - TLS_TCB_SIZE;
> > +	      }
> > +# endif
> > +	    break;
> > +	  default:
> > +	    _dl_reloc_bad_type (map, r_type, 0);
> > +	    break;
> > +	}
> > +    }
> > +}
> > +
> > +static inline void
> > +__attribute__ ((always_inline))
> > +elf_machine_rela_relative (Elf32_Addr l_addr, const Elf32_Rela *reloc,
> > +			   void *const reloc_addr_arg)
> > +{
> > +  Elf32_Addr *const reloc_addr = reloc_addr_arg;
> > +  *reloc_addr = l_addr + reloc->r_addend;
> > +}
> > +
> > +static inline void
> > +__attribute__ ((always_inline))
> > +elf_machine_lazy_rel (struct link_map *map, struct r_scope_elem *scope[],
> > +		      ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
> > +		      int skip_ifunc)
> > +{
> > +  Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset);
> > +  const unsigned int r_type = ELF32_R_TYPE (reloc->r_info);
> > +
> > +  if (__glibc_likely (r_type == R_OR1K_JMP_SLOT))
> > +      *reloc_addr += l_addr;
> > +  else if (__glibc_unlikely (r_type == R_OR1K_NONE))
> > +    return;
> > +  else
> > +    _dl_reloc_bad_type (map, r_type, 1);
> > +}
> > +
> > +#endif /* RESOLVE_MAP */
> > diff --git a/sysdeps/or1k/dl-start.S b/sysdeps/or1k/dl-start.S
> > new file mode 100644
> > index 0000000000..ecb1505427
> > --- /dev/null
> > +++ b/sysdeps/or1k/dl-start.S
> > @@ -0,0 +1,98 @@
> > +/* Machine-dependent ELF startup code.  OpenRISC version.
> > +   Copyright (C) 2021 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/>.  */
> > +
> > +#include <sysdep.h>
> > +
> > +/* Initial entry point code for the dynamic linker.
> > +   The function _dl_start is the real entry point;
> > +   it's return value is the user program's entry point.  */
> > +ENTRY (_start)
> > +	/* Count arguments in r11 */
> > +	l.ori	r3, r1, 0
> > +	l.movhi	r11, 0
> > +1:
> > +	l.addi	r3, r3, 4
> > +	l.lwz	r12, 0(r3)
> > +	l.sfnei	r12, 0
> > +	l.addi	r11, r11, 1
> > +	l.bf	1b
> > +	 l.nop
> > +	l.addi	r11, r11, -1
> > +	/* store argument counter to stack.  */
> > +	l.sw	0(r1), r11
> > +
> > +	/* Load the PIC register.  */
> > +	l.jal	0x8
> > +	 l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4)
> > +	l.ori	r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0)
> > +	l.add	r16, r16, r9
> > +
> > +	l.ori	r3, r1, 0
> > +
> > +	l.jal	_dl_start
> > +	 l.nop
> > +	/* Save user entry in a call saved reg.  */
> > +	l.ori	r22, r11, 0
> > +	/* Fall through to _dl_start_user.  */
> > +
> > +_dl_start_user:
> > +	/* Set up for _dl_init.  */
> > +
> > +	/* Load _rtld_local (a.k.a _dl_loaded).  */
> > +	l.lwz	r12, got(_rtld_local)(r16)
> > +	l.lwz	r3, 0(r12)
> > +
> > +	/* Load argc */
> > +	l.lwz	r18, got(_dl_argc)(r16)
> > +	l.lwz	r4, 0(r18)
> > +
> > +	/* Load argv */
> > +	l.lwz	r20, got(_dl_argv)(r16)
> > +	l.lwz	r5, 0(r20)
> > +
> > +	/* Load envp = &argv[argc + 1].  */
> > +	l.slli	r6, r4, 2
> > +	l.addi	r6, r6, 4
> > +	l.add	r6, r6, r5
> > +
> > +	l.jal	plt(_dl_init)
> > +	 l.nop
> > +
> > +	/* Now set up for user entry.
> > +	   The already defined ABI loads argc and argv from the stack.
> > +
> > +	   argc = 0(r1)
> > +	   argv = r1 + 4
> > +	*/
> > +
> > +	/* Load SP as argv - 4.  */
> > +	l.lwz	r3, 0(r20)
> > +	l.addi	r1, r3, -4
> > +
> > +	/* Save argc.  */
> > +	l.lwz	r3, 0(r18)
> > +	l.sw	0(r1), r3
> > +
> > +	/* Pass _dl_fini function address to _start.
> > +	   Next start.S will then pass this as rtld_fini to __libc_start_main.  */
> > +	l.lwz	r3, got(_dl_fini)(r16)
> > +
> > +	l.jr	r22
> > +	 l.nop
> > +
> > +END (_start)
> > diff --git a/sysdeps/or1k/ldsodefs.h b/sysdeps/or1k/ldsodefs.h
> > new file mode 100644
> > index 0000000000..89713fcc70
> > --- /dev/null
> > +++ b/sysdeps/or1k/ldsodefs.h
> > @@ -0,0 +1,40 @@
> > +/* Run-time dynamic linker data structures for loaded ELF shared objects.
> > +   Copyright (C) 2021 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	_OR1K_LDSODEFS_H
> > +#define	_OR1K_LDSODEFS_H	1
> > +
> > +#include <elf.h>
> > +
> > +struct La_or1k_regs;
> > +struct La_or1k_retval;
> > +
> > +#define ARCH_PLTENTER_MEMBERS						\
> > +    uintptr_t (*or1k_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *, \
> > +				  uintptr_t *, struct La_or1k_regs *, \
> > +				  unsigned int *, const char *name,	\
> > +				  long int *framesizep)
> > +
> > +#define ARCH_PLTEXIT_MEMBERS						\
> > +    unsigned int (*or1k_gnu_pltexit) (Elf32_Sym *, unsigned int, uintptr_t *, \
> > +				    uintptr_t *, const struct La_or1k_regs *, \
> > +				    struct La_or1k_retval *, const char *)
> > +
> > +#include_next <ldsodefs.h>
> > +
> > +#endif
> > diff --git a/sysdeps/or1k/sotruss-lib.c b/sysdeps/or1k/sotruss-lib.c
> > new file mode 100644
> > index 0000000000..3755b7afd5
> > --- /dev/null
> > +++ b/sysdeps/or1k/sotruss-lib.c
> > @@ -0,0 +1,51 @@
> > +/* Override generic sotruss-lib.c to define actual functions for OpenRISC.
> > +   Copyright (C) 2021 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_or1k_gnu_pltenter (ElfW(Sym) *sym __attribute__ ((unused)),
> 
> As before, I think you can use Elf32_Addr and Elf32_Sym directly.

OK.

> > +		       unsigned int ndx __attribute__ ((unused)),
> > +		       uintptr_t *refcook, uintptr_t *defcook,
> > +		       La_or1k_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_or1k_gnu_pltexit (ElfW(Sym) *sym, unsigned int ndx, uintptr_t *refcook,
> > +		      uintptr_t *defcook,
> > +		      const struct La_or1k_regs *inregs,
> > +		      struct La_or1k_retval *outregs,
> > +		      const char *symname)
> > +{
> > +  print_exit (refcook, defcook, symname, outregs->lrv_reg[0]);
> > +
> > +  return 0;
> > +}
> > diff --git a/sysdeps/or1k/start.S b/sysdeps/or1k/start.S
> > new file mode 100644
> > index 0000000000..0424355f36
> > --- /dev/null
> > +++ b/sysdeps/or1k/start.S
> > @@ -0,0 +1,99 @@
> > +/* start, OpenRISC version.
> > +   Copyright (C) 2021 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, write to the Free
> > +   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> > +   02111-1307 USA.  */
> > +
> > +/* This is the canonical entry point, usually the first thing in the text
> > +   segment.
> > +
> > +   sp   The stack contains the arguments and environment:
> > +    0(sp)     argc
> > +    4(sp)     argv[0]
> > +    ...
> > +    (4*argc)(sp)    NULL
> > +    (4*(argc+1))(sp)  envp[0]
> > +    ...
> > +    NULL
> > + */
> > +
> > +#define __ASSEMBLY__
> > +#include <sysdep.h>
> > +#include <entry.h>
> > +
> > +ENTRY (ENTRY_POINT)
> > +
> > +	/* Setup Arguments to the __libc_start_main function.  */
> > +
> > +	/* Take values for argc and argv off the stack.
> > +	   These will be passed as arguments two and three to main
> > +	   and thus go in registers r4 and r5, respectively.  */
> > +	l.lwz	r4, 0(r1)
> > +	l.addi	r5, r1, 4
> > +
> > +	/* Pass in rtld_fini from dl-start.S.  */
> > +	l.or	r8, r3, r3
> > +
> > +#ifdef PIC
> > +	/* Obtain a pointer to .got in r16 */
> > +	l.jal	0x8
> > +	 l.movhi r16, gotpchi(_GLOBAL_OFFSET_TABLE_-4)
> > +	l.ori	r16, r16, gotpclo(_GLOBAL_OFFSET_TABLE_+0)
> > +	l.add	r16, r16, r9
> > +
> > +	/* Pass in the the main symbol.  */
> > +	l.lwz	r3, got(main)(r16)
> > +#else
> > +	/* Pass in the the main symbol.  */
> > +	l.movhi r3, hi(main)
> > +	l.ori	r3, r3, lo(main)
> > +#endif
> > +	/* Used to be init and fini.  */
> > +	l.movhi	r6, 0x0
> > +	l.movhi	r7, 0x0
> > +
> > +	/* Push stack limit onto the stack.
> > +	   This provides the highest stack address to user code (as stack grows
> > +	   downwards.
> > +	   This is the seventh argument to __libc_start_main and thus needs to
> > +	   be passed on the stack.  */
> > +	l.sw	-4(r1), r1
> > +
> > +	/* Adjust stack to account for a total of 7 args (i.e. the last one is
> > +	   on the stack.  */
> > +	l.addi	r1, r1, -4
> > +
> > +	/* Clear the frame pointer and link register since this is the
> > +	   outermost frame.  */
> > +	l.movhi	r2, 0x0
> > +	l.movhi	r9, 0x0
> > +
> > +	/* Let the libc call main and exit with its return code.  */
> > +#ifdef PIC
> > +	l.j	plt(__libc_start_main)
> > +#else
> > +	l.j	__libc_start_main
> > +#endif
> > +	 l.nop
> > +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/or1k/tst-audit.h b/sysdeps/or1k/tst-audit.h
> > new file mode 100644
> > index 0000000000..66cb2ee48c
> > --- /dev/null
> > +++ b/sysdeps/or1k/tst-audit.h
> > @@ -0,0 +1,24 @@
> > +/* Definitions for testing PLT entry/exit auditing.  OpenRISC version.
> > +   Copyright (C) 2021 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_or1k_gnu_pltenter
> > +#define pltexit la_or1k_gnu_pltexit
> > +#define La_regs La_or1k_regs
> > +#define La_retval La_or1k_retval
> > +#define int_retval lrv_reg[0]