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Re: [PATCH 2/2] x86: Add elf_x86_backend_data
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Binutils <binutils at sourceware dot org>
- Date: Sat, 14 Oct 2017 11:28:54 -0700
- Subject: Re: [PATCH 2/2] x86: Add elf_x86_backend_data
- Authentication-results: sourceware.org; auth=none
- References: <20170914152629.GA23939@gmail.com>
On Thu, Sep 14, 2017 at 8:26 AM, H.J. Lu <hongjiu.lu@intel.com> wrote:
> Add plt0_pad_byte and target_os fields to elf_x86_link_hash_table.
> Replace elf_i386_backend_data and elf_x86_64_backend_data with
> elf_x86_backend_data.
>
> * elf32-i386.c (elf_i386_backend_data): Removed.
> (get_elf_i386_backend_data): Likewise.
> (elf_i386_arch_bed): Replace elf_i386_backend_data with
> elf_x86_backend_data.
> (elf_i386_get_synthetic_symtab): Likewise.
> (elf_i386_nacl_arch_bed): Likewise.
> (elf_i386_vxworks_arch_bed): Likewise.
> (elf_i386_relocate_section): Check target_os instead of
> is_vxworks.
> (elf_i386_finish_dynamic_symbol): Likewise.
> (elf_i386_finish_dynamic_sections): Use htab->plt0_pad_byte.
> Check target_os instead of is_vxworks.
> (elf_i386_link_setup_gnu_properties): Remove normal_target and
> is_vxworks. Initialize plt0_pad_byte.
> * elf64-x86-64.c (elf_x86_64_backend_data); Removed.
> (get_elf_x86_64_arch_data): Likewise.
> (get_elf_x86_64_backend_data): Likewise.
> (elf_x86_64_arch_bed): Replace elf_x86_64_backend_data with
> elf_x86_backend_data.
> (elf_x86_64_get_synthetic_symtab): Likewise.
> (elf_x86_64_nacl_arch_bed): Likewise.
> (elf_x86_64_link_setup_gnu_properties): Remove is_vxworks and
> normal_target. Initialize plt0_pad_byte.
> * elfxx-x86.c (elf_x86_allocate_dynrelocs): Check target_os
> instead of is_vxworks.
> (_bfd_x86_elf_size_dynamic_sections): Likewise.
> (_bfd_x86_elf_finish_dynamic_sections): Likewise.
> (_bfd_x86_elf_adjust_dynamic_symbol): Likewise.
> (_bfd_x86_elf_link_hash_table_create): Initialize target_os.
> (_bfd_x86_elf_link_setup_gnu_properties): Remove is_vxworks.
> Update normal_target. Set up plt0_pad_byte. Check target_os
> instead of is_vxworks.
> * elfxx-x86.h (elf_x86_target_os): New.
> (elf_x86_backend_data): Likewise.
> (get_elf_x86_backend_data): Likewise.
> (elf_x86_link_hash_table): Remove is_vxworks. Add plt0_pad_byte
> and target_os.
> (elf_x86_init_table): Remove normal_target and is_vxworks. Add
> plt0_pad_byte.
> ---
> bfd/elf32-i386.c | 53 +++++++++++++----------------------------------------
> bfd/elf64-x86-64.c | 35 +++++++++--------------------------
> bfd/elfxx-x86.c | 28 +++++++++++++++-------------
> bfd/elfxx-x86.h | 34 +++++++++++++++++++++++++---------
> 4 files changed, 62 insertions(+), 88 deletions(-)
>
> diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
> index 2daa163cbf..f11db44f0d 100644
> --- a/bfd/elf32-i386.c
> +++ b/bfd/elf32-i386.c
> @@ -820,30 +820,9 @@ static const struct elf_x86_non_lazy_plt_layout elf_i386_non_lazy_ibt_plt =
> #define PLTRESOLVE_RELOCS 2
> #define PLT_NON_JUMP_SLOT_RELOCS 2
>
> -/* Architecture-specific backend data for i386. */
> -
> -struct elf_i386_backend_data
> -{
> - /* Value used to fill the unused bytes of the first PLT entry. */
> - bfd_byte plt0_pad_byte;
> -
> - /* Target system. */
> - enum
> - {
> - is_normal,
> - is_vxworks,
> - is_nacl
> - } os;
> -};
> -
> -#define get_elf_i386_backend_data(abfd) \
> - ((const struct elf_i386_backend_data *) \
> - get_elf_backend_data (abfd)->arch_data)
> -
> /* These are the standard parameters. */
> -static const struct elf_i386_backend_data elf_i386_arch_bed =
> +static const struct elf_x86_backend_data elf_i386_arch_bed =
> {
> - 0, /* plt0_pad_byte */
> is_normal /* os */
> };
>
> @@ -2047,7 +2026,7 @@ elf_i386_relocate_section (bfd *output_bfd,
> local_tlsdesc_gotents = elf_x86_local_tlsdesc_gotent (input_bfd);
> /* We have to handle relocations in vxworks .tls_vars sections
> specially, because the dynamic loader is 'weird'. */
> - is_vxworks_tls = (htab->is_vxworks
> + is_vxworks_tls = (htab->target_os == is_vxworks
> && bfd_link_pic (info)
> && !strcmp (input_section->output_section->name,
> ".tls_vars"));
> @@ -3714,7 +3693,7 @@ elf_i386_finish_dynamic_symbol (bfd *output_bfd,
> resolved_plt->contents + plt_offset
> + htab->plt.plt_got_offset);
>
> - if (htab->is_vxworks)
> + if (htab->target_os == is_vxworks)
> {
> int s, k, reloc_index;
>
> @@ -4120,13 +4099,10 @@ elf_i386_finish_dynamic_sections (bfd *output_bfd,
> {
> /* Fill in the special first entry in the procedure linkage
> table. */
> - const struct elf_i386_backend_data *abed
> - = get_elf_i386_backend_data (output_bfd);
> -
> memcpy (htab->elf.splt->contents, htab->plt.plt0_entry,
> htab->lazy_plt->plt0_entry_size);
> memset (htab->elf.splt->contents + htab->lazy_plt->plt0_entry_size,
> - abed->plt0_pad_byte,
> + htab->plt0_pad_byte,
> htab->plt.plt_entry_size - htab->lazy_plt->plt0_entry_size);
> if (!bfd_link_pic (info))
> {
> @@ -4143,7 +4119,7 @@ elf_i386_finish_dynamic_sections (bfd *output_bfd,
> htab->elf.splt->contents
> + htab->lazy_plt->plt0_got2_offset);
>
> - if (htab->is_vxworks)
> + if (htab->target_os == is_vxworks)
> {
> Elf_Internal_Rela rel;
> int num_plts = (htab->elf.splt->size
> @@ -4284,7 +4260,7 @@ elf_i386_get_synthetic_symtab (bfd *abfd,
> lazy_plt = NULL;
> non_lazy_ibt_plt = NULL;
> lazy_ibt_plt = NULL;
> - switch (get_elf_i386_backend_data (abfd)->os)
> + switch (get_elf_x86_backend_data (abfd)->target_os)
> {
> case is_normal:
> non_lazy_plt = &elf_i386_non_lazy_plt;
> @@ -4443,25 +4419,24 @@ elf_i386_link_setup_gnu_properties (struct bfd_link_info *info)
> {
> struct elf_x86_init_table init_table;
>
> - init_table.normal_target = FALSE;
> - init_table.is_vxworks = FALSE;
> - switch (get_elf_i386_backend_data (info->output_bfd)->os)
> + switch (get_elf_x86_backend_data (info->output_bfd)->target_os)
> {
> case is_normal:
> + init_table.plt0_pad_byte = 0x0;
> init_table.lazy_plt = &elf_i386_lazy_plt;
> init_table.non_lazy_plt = &elf_i386_non_lazy_plt;
> init_table.lazy_ibt_plt = &elf_i386_lazy_ibt_plt;
> init_table.non_lazy_ibt_plt = &elf_i386_non_lazy_ibt_plt;
> - init_table.normal_target = TRUE;
> break;
> case is_vxworks:
> + init_table.plt0_pad_byte = 0x90;
> init_table.lazy_plt = &elf_i386_lazy_plt;
> init_table.non_lazy_plt = NULL;
> init_table.lazy_ibt_plt = NULL;
> init_table.non_lazy_ibt_plt = NULL;
> - init_table.is_vxworks = TRUE;
> break;
> case is_nacl:
> + init_table.plt0_pad_byte = 0x90;
> init_table.lazy_plt = &elf_i386_nacl_plt;
> init_table.non_lazy_plt = NULL;
> init_table.lazy_ibt_plt = NULL;
> @@ -4814,7 +4789,7 @@ static const bfd_byte elf_i386_nacl_eh_frame_plt[] =
> || PLT_FDE_LENGTH != 36 \
> || PLT_FDE_START_OFFSET != 4 + PLT_CIE_LENGTH + 8 \
> || PLT_FDE_LEN_OFFSET != 4 + PLT_CIE_LENGTH + 12)
> -# error "Need elf_i386_backend_data parameters for eh_frame_plt offsets!"
> +# error "Need elf_x86_backend_data parameters for eh_frame_plt offsets!"
> #endif
> PLT_CIE_LENGTH, 0, 0, 0, /* CIE length */
> 0, 0, 0, 0, /* CIE ID */
> @@ -4868,9 +4843,8 @@ static const struct elf_x86_lazy_plt_layout elf_i386_nacl_plt =
> sizeof (elf_i386_nacl_eh_frame_plt) /* eh_frame_plt_size */
> };
>
> -static const struct elf_i386_backend_data elf_i386_nacl_arch_bed =
> +static const struct elf_x86_backend_data elf_i386_nacl_arch_bed =
> {
> - 0x90, /* plt0_pad_byte: nop insn */
> is_nacl /* os */
> };
>
> @@ -4914,9 +4888,8 @@ elf32_i386_nacl_elf_object_p (bfd *abfd)
> #undef elf_backend_plt_alignment
> #define elf_backend_plt_alignment 4
>
> -static const struct elf_i386_backend_data elf_i386_vxworks_arch_bed =
> +static const struct elf_x86_backend_data elf_i386_vxworks_arch_bed =
> {
> - 0x90, /* plt0_pad_byte */
> is_vxworks /* os */
> };
>
> diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
> index fd58bd7139..188a24265a 100644
> --- a/bfd/elf64-x86-64.c
> +++ b/bfd/elf64-x86-64.c
> @@ -816,24 +816,6 @@ static const bfd_byte elf_x86_64_eh_frame_non_lazy_plt[] =
> DW_CFA_nop, DW_CFA_nop, DW_CFA_nop
> };
>
> -/* Architecture-specific backend data for x86-64. */
> -
> -struct elf_x86_64_backend_data
> -{
> - /* Target system. */
> - enum
> - {
> - is_normal,
> - is_nacl
> - } os;
> -};
> -
> -#define get_elf_x86_64_arch_data(bed) \
> - ((const struct elf_x86_64_backend_data *) (bed)->arch_data)
> -
> -#define get_elf_x86_64_backend_data(abfd) \
> - get_elf_x86_64_arch_data (get_elf_backend_data (abfd))
> -
> /* These are the standard parameters. */
> static const struct elf_x86_lazy_plt_layout elf_x86_64_lazy_plt =
> {
> @@ -963,7 +945,7 @@ static const struct elf_x86_non_lazy_plt_layout elf_x32_non_lazy_ibt_plt =
> sizeof (elf_x86_64_eh_frame_non_lazy_plt) /* eh_frame_plt_size */
> };
>
> -static const struct elf_x86_64_backend_data elf_x86_64_arch_bed =
> +static const struct elf_x86_backend_data elf_x86_64_arch_bed =
> {
> is_normal /* os */
> };
> @@ -4620,7 +4602,7 @@ elf_x86_64_get_synthetic_symtab (bfd *abfd,
> if (relsize <= 0)
> return -1;
>
> - if (get_elf_x86_64_backend_data (abfd)->os == is_normal)
> + if (get_elf_x86_backend_data (abfd)->target_os == is_normal)
> {
> lazy_plt = &elf_x86_64_lazy_plt;
> non_lazy_plt = &elf_x86_64_non_lazy_plt;
> @@ -4968,8 +4950,11 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
> != (int) R_X86_64_GNU_VTENTRY))
> abort ();
>
> - init_table.is_vxworks = FALSE;
> - if (get_elf_x86_64_backend_data (info->output_bfd)->os == is_normal)
> + /* This is unused for x86-64. */
> + init_table.plt0_pad_byte = 0x90;
> +
> + if (get_elf_x86_backend_data (info->output_bfd)->target_os
> + == is_normal)
> {
> if (info->bndplt)
> {
> @@ -4992,7 +4977,6 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
> init_table.lazy_ibt_plt = &elf_x32_lazy_ibt_plt;
> init_table.non_lazy_ibt_plt = &elf_x32_non_lazy_ibt_plt;
> }
> - init_table.normal_target = TRUE;
> }
> else
> {
> @@ -5000,7 +4984,6 @@ elf_x86_64_link_setup_gnu_properties (struct bfd_link_info *info)
> init_table.non_lazy_plt = NULL;
> init_table.lazy_ibt_plt = NULL;
> init_table.non_lazy_ibt_plt = NULL;
> - init_table.normal_target = FALSE;
> }
>
> if (ABI_64_P (info->output_bfd))
> @@ -5265,7 +5248,7 @@ static const bfd_byte elf_x86_64_nacl_eh_frame_plt[] =
> || PLT_FDE_LENGTH != 36 \
> || PLT_FDE_START_OFFSET != 4 + PLT_CIE_LENGTH + 8 \
> || PLT_FDE_LEN_OFFSET != 4 + PLT_CIE_LENGTH + 12)
> -# error "Need elf_x86_64_backend_data parameters for eh_frame_plt offsets!"
> +# error "Need elf_x86_backend_data parameters for eh_frame_plt offsets!"
> #endif
> PLT_CIE_LENGTH, 0, 0, 0, /* CIE length */
> 0, 0, 0, 0, /* CIE ID */
> @@ -5319,7 +5302,7 @@ static const struct elf_x86_lazy_plt_layout elf_x86_64_nacl_plt =
> sizeof (elf_x86_64_nacl_eh_frame_plt) /* eh_frame_plt_size */
> };
>
> -static const struct elf_x86_64_backend_data elf_x86_64_nacl_arch_bed =
> +static const struct elf_x86_backend_data elf_x86_64_nacl_arch_bed =
> {
> is_nacl /* os */
> };
> diff --git a/bfd/elfxx-x86.c b/bfd/elfxx-x86.c
> index a0fe9d19ff..d78c1e485f 100644
> --- a/bfd/elfxx-x86.c
> +++ b/bfd/elfxx-x86.c
> @@ -262,7 +262,7 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h,
> }
> }
>
> - if (htab->is_vxworks && !bfd_link_pic (info))
> + if (htab->target_os == is_vxworks && !bfd_link_pic (info))
> {
> /* VxWorks has a second set of relocations for each PLT entry
> in executables. They go in a separate relocation section,
> @@ -406,7 +406,7 @@ elf_x86_allocate_dynrelocs (struct elf_link_hash_entry *h,
> }
> }
>
> - if (htab->is_vxworks)
> + if (htab->target_os == is_vxworks)
> {
> struct elf_dyn_relocs **pp;
> for (pp = &eh->dyn_relocs; (p = *pp) != NULL; )
> @@ -799,6 +799,7 @@ _bfd_x86_elf_link_hash_table_create (bfd *abfd)
> }
> }
> ret->target_id = bed->target_id;
> + ret->target_os = get_elf_x86_backend_data (abfd)->target_os;
>
> ret->loc_hash_table = htab_try_create (1024,
> _bfd_x86_elf_local_htab_hash,
> @@ -924,7 +925,7 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd,
> linker script /DISCARD/, so we'll be discarding
> the relocs too. */
> }
> - else if (htab->is_vxworks
> + else if (htab->target_os == is_vxworks
> && strcmp (p->sec->output_section->name,
> ".tls_vars") == 0)
> {
> @@ -1285,7 +1286,7 @@ _bfd_x86_elf_size_dynamic_sections (bfd *output_bfd,
> return FALSE;
> }
> }
> - if (htab->is_vxworks
> + if (htab->target_os == is_vxworks
> && !elf_vxworks_add_dynamic_entries (output_bfd, info))
> return FALSE;
> }
> @@ -1377,7 +1378,7 @@ _bfd_x86_elf_finish_dynamic_sections (bfd *output_bfd,
> switch (dyn.d_tag)
> {
> default:
> - if (htab->is_vxworks
> + if (htab->target_os == is_vxworks
> && elf_vxworks_finish_dynamic_entry (output_bfd, &dyn))
> break;
> continue;
> @@ -1836,7 +1837,7 @@ _bfd_x86_elf_adjust_dynamic_symbol (struct bfd_link_info *info,
> if (ELIMINATE_COPY_RELOCS
> && (bed->target_id == X86_64_ELF_DATA
> || (!eh->gotoff_ref
> - && !htab->is_vxworks)))
> + && htab->target_os != is_vxworks)))
> {
> for (p = eh->dyn_relocs; p != NULL; p = p->next)
> {
> @@ -2414,13 +2415,14 @@ error_alignment:
> if (htab == NULL)
> return pbfd;
>
> - htab->is_vxworks = init_table->is_vxworks;
> htab->r_info = init_table->r_info;
> htab->r_sym = init_table->r_sym;
>
> if (bfd_link_relocatable (info))
> return pbfd;
>
> + htab->plt0_pad_byte = init_table->plt0_pad_byte;
> +
> use_ibt_plt = info->ibtplt || info->ibt;
> if (!use_ibt_plt && pbfd != NULL)
> {
> @@ -2472,11 +2474,15 @@ error_alignment:
> }
> }
>
> + /* Return if there are no normal input files. */
> + if (dynobj == NULL)
> + return pbfd;
> +
> /* Even when lazy binding is disabled by "-z now", the PLT0 entry may
> still be used with LD_AUDIT or LD_PROFILE if PLT entry is used for
> canonical function address. */
> htab->plt.has_plt0 = 1;
> - normal_target = init_table->normal_target;
> + normal_target = htab->target_os == is_normal;
>
> if (normal_target)
> {
> @@ -2539,11 +2545,7 @@ error_alignment:
> htab->plt.eh_frame_plt = htab->lazy_plt->eh_frame_plt;
> }
>
> - /* Return if there are no normal input files. */
> - if (dynobj == NULL)
> - return pbfd;
> -
> - if (htab->is_vxworks
> + if (htab->target_os == is_vxworks
> && !elf_vxworks_create_dynamic_sections (dynobj, info,
> &htab->srelplt2))
> {
> diff --git a/bfd/elfxx-x86.h b/bfd/elfxx-x86.h
> index 3d6366f16b..5e33cdd1ba 100644
> --- a/bfd/elfxx-x86.h
> +++ b/bfd/elfxx-x86.h
> @@ -256,6 +256,13 @@ struct elf_x86_plt_layout
> #define elf_x86_hash_entry(ent) \
> ((struct elf_x86_link_hash_entry *)(ent))
>
> +enum elf_x86_target_os
> +{
> + is_normal,
> + is_vxworks,
> + is_nacl
> +};
> +
> /* x86 ELF linker hash table. */
>
> struct elf_x86_link_hash_table
> @@ -311,10 +318,6 @@ struct elf_x86_link_hash_table
> to read-only sections. */
> bfd_boolean readonly_dynrelocs_against_ifunc;
>
> - /* TRUE if this is a VxWorks x86 target. This is only used for
> - i386. */
> - bfd_boolean is_vxworks;
> -
> /* The (unloaded but important) .rel.plt.unloaded section on VxWorks.
> This is used for i386 only. */
> asection *srelplt2;
> @@ -329,10 +332,15 @@ struct elf_x86_link_hash_table
> yet. This is only used for x86-64. */
> bfd_vma tlsdesc_plt;
>
> + /* Value used to fill the unused bytes of the first PLT entry. This
> + is only used for i386. */
> + bfd_byte plt0_pad_byte;
> +
> bfd_vma (*r_info) (bfd_vma, bfd_vma);
> bfd_vma (*r_sym) (bfd_vma);
> bfd_boolean (*is_reloc_section) (const char *);
> enum elf_target_id target_id;
> + enum elf_x86_target_os target_os;
> unsigned int sizeof_reloc;
> unsigned int dt_reloc;
> unsigned int dt_reloc_sz;
> @@ -344,6 +352,18 @@ struct elf_x86_link_hash_table
> const char *tls_get_addr;
> };
>
> +/* Architecture-specific backend data for x86. */
> +
> +struct elf_x86_backend_data
> +{
> + /* Target system. */
> + enum elf_x86_target_os target_os;
> +};
> +
> +#define get_elf_x86_backend_data(abfd) \
> + ((const struct elf_x86_backend_data *) \
> + get_elf_backend_data (abfd)->arch_data)
> +
> struct elf_x86_init_table
> {
> /* The lazy PLT layout. */
> @@ -358,11 +378,7 @@ struct elf_x86_init_table
> /* The non-lazy PLT layout for IBT. */
> const struct elf_x86_non_lazy_plt_layout *non_lazy_ibt_plt;
>
> - /* TRUE if this is a normal x86 target. */
> - bfd_boolean normal_target;
> -
> - /* TRUE if this is a VxWorks x86 target. */
> - bfd_boolean is_vxworks;
> + bfd_byte plt0_pad_byte;
>
> bfd_vma (*r_info) (bfd_vma, bfd_vma);
> bfd_vma (*r_sym) (bfd_vma);
> --
> 2.13.5
>
I am checking it in.
--
H.J.