On 01/06/2020 19:18, Vineet Gupta wrote:
> The existing macros are fragile and expect local variables with a
> certain name. Fix this by defining them as functions with default
> implementation in a new header dl-runtime.h which arches can override
> if need be.
>
> This came up during ARC port review, hence the need for argument pltgot
> in reloc_index() which is not needed by existing ports.
>
> This patch potentially only affects hppa/x86 ports,
> build tested for both those configs and a few more.
>
> Suggested-by: Adhemerval Zanella <adhemerval.zanella@xxxxxxxxxx>
LGTM, thanks. There are just style nits in the one-line comment
for new files.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@xxxxxxxxxx>
> ---
> elf/dl-runtime.c | 28 +++++++++++++++++-----------
> elf/dl-runtime.h | 30 ++++++++++++++++++++++++++++++
> sysdeps/hppa/dl-runtime.c | 4 ----
> sysdeps/hppa/dl-runtime.h | 31 +++++++++++++++++++++++++++++++
> sysdeps/x86_64/dl-runtime.c | 9 ---------
> sysdeps/x86_64/dl-runtime.h | 35 +++++++++++++++++++++++++++++++++++
> 6 files changed, 113 insertions(+), 24 deletions(-)
> create mode 100644 elf/dl-runtime.h
> create mode 100644 sysdeps/hppa/dl-runtime.h
> delete mode 100644 sysdeps/x86_64/dl-runtime.c
> create mode 100644 sysdeps/x86_64/dl-runtime.h
>
> diff --git a/elf/dl-runtime.c b/elf/dl-runtime.c
> index cf5f1d3e82e1..85a229f6f019 100644
> --- a/elf/dl-runtime.c
> +++ b/elf/dl-runtime.c
> @@ -27,6 +27,7 @@
> #include "dynamic-link.h"
> #include <tls.h>
> #include <dl-irel.h>
> +#include <dl-runtime.h>
>
>
> #if (!ELF_MACHINE_NO_RELA && !defined ELF_MACHINE_PLT_REL) \
> @@ -42,13 +43,6 @@
> # define ARCH_FIXUP_ATTRIBUTE
> #endif
>
> -#ifndef reloc_offset
> -# define reloc_offset reloc_arg
> -# define reloc_index reloc_arg / sizeof (PLTREL)
> -#endif
> -
> -
> -
> /* This function is called through a special trampoline from the PLT the
> first time each PLT entry is called. We must perform the relocation
> specified in the PLT of the given shared object, and return the resolved
> @@ -68,8 +62,11 @@ _dl_fixup (
> = (const void *) D_PTR (l, l_info[DT_SYMTAB]);
> const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
>
> + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]);
> +
> const PLTREL *const reloc
> - = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + reloc_offset);
> + = (const void *) (D_PTR (l, l_info[DT_JMPREL])
> + + reloc_offset (pltgot, reloc_arg));
> const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (reloc->r_info)];
> const ElfW(Sym) *refsym = sym;
> void *const rel_addr = (void *)(l->l_addr + reloc->r_offset);
Ok.
> @@ -180,9 +177,12 @@ _dl_profile_fixup (
> l, reloc_arg);
> }
>
> + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]);
> +
> /* This is the address in the array where we store the result of previous
> relocations. */
> - struct reloc_result *reloc_result = &l->l_reloc_result[reloc_index];
> + struct reloc_result *reloc_result
> + = &l->l_reloc_result[reloc_index (pltgot, reloc_arg, sizeof (PLTREL))];
>
> /* CONCURRENCY NOTES:
>
Ok.
> @@ -219,8 +219,11 @@ _dl_profile_fixup (
> = (const void *) D_PTR (l, l_info[DT_SYMTAB]);
> const char *strtab = (const char *) D_PTR (l, l_info[DT_STRTAB]);
>
> + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]);
> +
> const PLTREL *const reloc
> - = (const void *) (D_PTR (l, l_info[DT_JMPREL]) + reloc_offset);
> + = (const void *) (D_PTR (l, l_info[DT_JMPREL])
> + + reloc_offset (pltgot, reloc_arg));
> const ElfW(Sym) *refsym = &symtab[ELFW(R_SYM) (reloc->r_info)];
> const ElfW(Sym) *defsym = refsym;
> lookup_t result;
Ok.
> @@ -485,11 +488,14 @@ _dl_call_pltexit (struct link_map *l, ElfW(Word) reloc_arg,
> const void *inregs, void *outregs)
> {
> #ifdef SHARED
> + const uintptr_t pltgot = (uintptr_t) D_PTR (l, l_info[DT_PLTGOT]);
> +
> /* This is the address in the array where we store the result of previous
> relocations. */
> // XXX Maybe the bound information must be stored on the stack since
> // XXX with bind_not a new value could have been stored in the meantime.
> - struct reloc_result *reloc_result = &l->l_reloc_result[reloc_index];
> + struct reloc_result *reloc_result =
> + &l->l_reloc_result[reloc_index (pltgot, reloc_arg, sizeof (PLTREL))];
> ElfW(Sym) *defsym = ((ElfW(Sym) *) D_PTR (reloc_result->bound,
> l_info[DT_SYMTAB])
> + reloc_result->boundndx);
Ok.
> diff --git a/elf/dl-runtime.h b/elf/dl-runtime.h
> new file mode 100644
> index 000000000000..dd87d799465e
> --- /dev/null
> +++ b/elf/dl-runtime.h
> @@ -0,0 +1,30 @@
> +/* Helpers for On-demand PLT fixup for shared objects. Generic version.
Double space after period.
> + Copyright (C) 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, write to the Free
> + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> + 02111-1307 USA. */
> +
> +static inline uintptr_t
> +reloc_offset (uintptr_t plt0, uintptr_t pltn)
> +{
> + return pltn;
> +}
> +
> +static inline uintptr_t
> +reloc_index (uintptr_t plt0, uintptr_t pltn, size_t size)
> +{
> + return pltn / size;
> +}
Ok.
> diff --git a/sysdeps/hppa/dl-runtime.c b/sysdeps/hppa/dl-runtime.c
> index 885a3f1837cb..2d061b150f06 100644
> --- a/sysdeps/hppa/dl-runtime.c
> +++ b/sysdeps/hppa/dl-runtime.c
> @@ -17,10 +17,6 @@
> Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> 02111-1307 USA. */
>
> -/* Clear PA_GP_RELOC bit in relocation offset. */
> -#define reloc_offset (reloc_arg & ~PA_GP_RELOC)
> -#define reloc_index (reloc_arg & ~PA_GP_RELOC) / sizeof (PLTREL)
> -
> #include <elf/dl-runtime.c>
>
> /* The caller has encountered a partially relocated function descriptor.
Ok.
> diff --git a/sysdeps/hppa/dl-runtime.h b/sysdeps/hppa/dl-runtime.h
> new file mode 100644
> index 000000000000..be3bc929c74c
> --- /dev/null
> +++ b/sysdeps/hppa/dl-runtime.h
> @@ -0,0 +1,31 @@
> +/* Helpers for On-demand PLT fixup for shared objects. HPAA version.
Double space after period.
> + Copyright (C) 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, write to the Free
> + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> + 02111-1307 USA. */
> +
> +/* Clear PA_GP_RELOC bit in relocation offset. */
> +static inline uintptr_t
> +reloc_offset (uintptr_t plt0, uintptr_t pltn)
> +{
> + return pltn & ~PA_GP_RELOC;
> +}
> +
> +static inline uintptr_t
> +reloc_index (uintptr_t plt0, uintptr_t pltn, size_t size)
> +{
> + return (pltn & ~PA_GP_RELOC )/ size;
> +}
Ok,
> diff --git a/sysdeps/x86_64/dl-runtime.c b/sysdeps/x86_64/dl-runtime.c
> deleted file mode 100644
> index b625d1e88257..000000000000
> --- a/sysdeps/x86_64/dl-runtime.c
> +++ /dev/null
> @@ -1,9 +0,0 @@
> -/* The ABI calls for the PLT stubs to pass the index of the relocation
> - and not its offset. In _dl_profile_fixup and _dl_call_pltexit we
> - also use the index. Therefore it is wasteful to compute the offset
> - in the trampoline just to reverse the operation immediately
> - afterwards. */
> -#define reloc_offset reloc_arg * sizeof (PLTREL)
> -#define reloc_index reloc_arg
> -
> -#include <elf/dl-runtime.c>
Ok.
> diff --git a/sysdeps/x86_64/dl-runtime.h b/sysdeps/x86_64/dl-runtime.h
> new file mode 100644
> index 000000000000..b82fdce8367d
> --- /dev/null
> +++ b/sysdeps/x86_64/dl-runtime.h
> @@ -0,0 +1,35 @@
> +/* Helpers for On-demand PLT fixup for shared objects. x86_64 version.
Double space after period.
> + Copyright (C) 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, write to the Free
> + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
> + 02111-1307 USA. */
> +
> +/* The ABI calls for the PLT stubs to pass the index of the relocation
> + and not its offset. In _dl_profile_fixup and _dl_call_pltexit we
> + also use the index. Therefore it is wasteful to compute the offset
> + in the trampoline just to reverse the operation immediately
> + afterwards. */
> +static inline uintptr_t
> +reloc_offset (uintptr_t plt0, uintptr_t pltn)
> +{
> + return pltn * sizeof (ElfW(Rela));
> +}
> +
> +static inline uintptr_t
> +reloc_index (uintptr_t plt0, uintptr_t pltn, size_t size)
> +{
> + return pltn;
> +}
>
Ok.
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