[PATCH] elf: Add <dl-debug.h>
H.J. Lu
hjl.tools@gmail.com
Sat Jan 1 16:17:17 GMT 2022
On Sat, Dec 25, 2021 at 12:23 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> Add <dl-debug.h> to setup debugging entry in PT_DYNAMIC segment to support
> DT_DEBUG, DT_MIPS_RLD_MAP_REL and DT_MIPS_RLD_MAP.
>
> Tested on x86-64, x32 and i686 as well as with build-many-glibcs.py.
> ---
> elf/dl-reloc-static-pie.c | 11 ++--------
> elf/rtld.c | 13 ++++--------
> sysdeps/generic/dl-debug.h | 33 ++++++++++++++++++++++++++++++
> sysdeps/mips/dl-debug.h | 41 ++++++++++++++++++++++++++++++++++++++
> sysdeps/mips/dl-machine.h | 15 --------------
> 5 files changed, 80 insertions(+), 33 deletions(-)
> create mode 100644 sysdeps/generic/dl-debug.h
> create mode 100644 sysdeps/mips/dl-debug.h
>
> diff --git a/elf/dl-reloc-static-pie.c b/elf/dl-reloc-static-pie.c
> index 5b85df8a2e..ad91721fe3 100644
> --- a/elf/dl-reloc-static-pie.c
> +++ b/elf/dl-reloc-static-pie.c
> @@ -24,6 +24,7 @@
> #include <ldsodefs.h>
>
> #include <dl-machine.h>
> +#include <dl-debug.h>
>
> #define RESOLVE_MAP(map, scope, sym, version, flags) map
> #include "dynamic-link.h"
> @@ -68,14 +69,6 @@ _dl_relocate_static_pie (void)
>
> /* Set up debugging before the debugger is notified for the first
> time. */
> -# ifdef ELF_MACHINE_DEBUG_SETUP
> - /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
> - ELF_MACHINE_DEBUG_SETUP (main_map, r);
> -# else
> - if (main_map->l_info[DT_DEBUG] != NULL)
> - /* There is a DT_DEBUG entry in the dynamic section. Fill it in
> - with the run-time address of the r_debug structure */
> - main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
> -# endif
> + elf_setup_debug_entry (main_map, r);
> }
> #endif
> diff --git a/elf/rtld.c b/elf/rtld.c
> index 4b09e84b0d..f75cb37e47 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -62,6 +62,9 @@
> #define RESOLVE_MAP(map, scope, sym, version, flags) map
> #include "dynamic-link.h"
>
> +/* Must include after <dl-machine.h> for DT_MIPS definition. */
> +#include <dl-debug.h>
> +
> /* Only enables rtld profiling for architectures which provides non generic
> hp-timing support. The generic support requires either syscall
> (clock_gettime), which will incur in extra overhead on loading time.
> @@ -1796,15 +1799,7 @@ dl_main (const ElfW(Phdr) *phdr,
> size_t count_modids = _dl_count_modids ();
>
> /* Set up debugging before the debugger is notified for the first time. */
> -#ifdef ELF_MACHINE_DEBUG_SETUP
> - /* Some machines (e.g. MIPS) don't use DT_DEBUG in this way. */
> - ELF_MACHINE_DEBUG_SETUP (main_map, r);
> -#else
> - if (main_map->l_info[DT_DEBUG] != NULL)
> - /* There is a DT_DEBUG entry in the dynamic section. Fill it in
> - with the run-time address of the r_debug structure */
> - main_map->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
> -#endif
> + elf_setup_debug_entry (main_map, r);
>
> /* We start adding objects. */
> r->r_state = RT_ADD;
> diff --git a/sysdeps/generic/dl-debug.h b/sysdeps/generic/dl-debug.h
> new file mode 100644
> index 0000000000..b492c0bcc6
> --- /dev/null
> +++ b/sysdeps/generic/dl-debug.h
> @@ -0,0 +1,33 @@
> +/* Debugging support. Generic 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_DEBUG_H
> +#define _DL_DEBUG_H
> +
> +/* There is a DT_DEBUG entry in the dynamic section. Fill it in with the
> + run-time address of the r_debug structure */
> +
> +static inline void
> +__attribute ((always_inline))
> +elf_setup_debug_entry (struct link_map *l, struct r_debug *r)
> +{
> + if (l->l_info[DT_DEBUG] != NULL)
> + l->l_info[DT_DEBUG]->d_un.d_ptr = (ElfW(Addr)) r;
> +}
> +
> +#endif /* _DL_DEBUG_H */
> diff --git a/sysdeps/mips/dl-debug.h b/sysdeps/mips/dl-debug.h
> new file mode 100644
> index 0000000000..a4c8d49309
> --- /dev/null
> +++ b/sysdeps/mips/dl-debug.h
> @@ -0,0 +1,41 @@
> +/* Debugging support. MIPS 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_DEBUG_H
> +#define _DL_DEBUG_H
> +
> +/* If there is a DT_MIPS_RLD_MAP_REL or DT_MIPS_RLD_MAP entry in the
> + dynamic section, fill in the debug map pointer with the run-time
> + address of the r_debug structure. */
> +
> +static inline void
> +__attribute ((always_inline))
> +elf_setup_debug_entry (struct link_map *l, struct r_debug *r)
> +{
> + if (l->l_info[DT_MIPS (RLD_MAP_REL)] != NULL)
> + {
> + char *ptr = (char *) l->l_info[DT_MIPS (RLD_MAP_REL)];
> + ptr += l->l_info[DT_MIPS (RLD_MAP_REL)]->d_un.d_val;
> + *(ElfW(Addr) *) ptr = (ElfW(Addr)) r;
> + }
> + else if (l->l_info[DT_MIPS (RLD_MAP)] != NULL)
> + *(ElfW(Addr) *) (l->l_info[DT_MIPS (RLD_MAP)]->d_un.d_ptr)
> + = (ElfW(Addr)) r;
> +}
> +
> +#endif /* _DL_DEBUG_H */
> diff --git a/sysdeps/mips/dl-machine.h b/sysdeps/mips/dl-machine.h
> index d7b8341b74..ea8c881807 100644
> --- a/sysdeps/mips/dl-machine.h
> +++ b/sysdeps/mips/dl-machine.h
> @@ -65,21 +65,6 @@
> in l_info array. */
> #define DT_MIPS(x) (DT_MIPS_##x - DT_LOPROC + DT_NUM)
>
> -/* If there is a DT_MIPS_RLD_MAP_REL or DT_MIPS_RLD_MAP entry in the dynamic
> - section, fill in the debug map pointer with the run-time address of the
> - r_debug structure. */
> -#define ELF_MACHINE_DEBUG_SETUP(l,r) \
> -do { if ((l)->l_info[DT_MIPS (RLD_MAP_REL)]) \
> - { \
> - char *ptr = (char *)(l)->l_info[DT_MIPS (RLD_MAP_REL)]; \
> - ptr += (l)->l_info[DT_MIPS (RLD_MAP_REL)]->d_un.d_val; \
> - *(ElfW(Addr) *)ptr = (ElfW(Addr)) (r); \
> - } \
> - else if ((l)->l_info[DT_MIPS (RLD_MAP)]) \
> - *(ElfW(Addr) *)((l)->l_info[DT_MIPS (RLD_MAP)]->d_un.d_ptr) = \
> - (ElfW(Addr)) (r); \
> - } while (0)
> -
> #if ((defined __mips_nan2008 && !defined HAVE_MIPS_NAN2008) \
> || (!defined __mips_nan2008 && defined HAVE_MIPS_NAN2008))
> # error "Configuration inconsistency: __mips_nan2008 != HAVE_MIPS_NAN2008, overridden CFLAGS?"
> --
> 2.33.1
>
If there is no objection, I will check it in on Monday.
--
H.J.
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