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Re: [RFC PATCH, binutils, ARM 8/11, ping3] Add support for ARMv8-M Secure Gateway veneer generation
- From: "Richard Earnshaw (lists)" <Richard dot Earnshaw at arm dot com>
- To: Thomas Preudhomme <thomas dot preudhomme at foss dot arm dot com>
- Cc: binutils at sourceware dot org
- Date: Thu, 4 Aug 2016 09:59:11 +0100
- Subject: Re: [RFC PATCH, binutils, ARM 8/11, ping3] Add support for ARMv8-M Secure Gateway veneer generation
- Authentication-results: sourceware.org; auth=none
- References: <005001d13d57$e3fb95a0$abf2c0e0$@foss.arm.com> <12243290.AlEVVf5MU2@e108577-lin> <7317991.OM3arAhmc6@e108577-lin> <1731627.tSuCaJfX6g@e108577-lin>
On 03/08/16 09:52, Thomas Preudhomme wrote:
> Hi Richard,
>
> How do you find the reworded comment for cmse_scan?
>
Yes, much better. Thanks.
Sorry for the delay replying. This patch is OK.
R.
> Best regards,
>
> Thomas
>
> On Tuesday 26 July 2016 12:07:26 Thomas Preudhomme wrote:
>> Hi Richard,
>>
>> Ping?
>>
>> Best regards,
>>
>> Thomas
>>
>> On Thursday 14 July 2016 10:14:57 Thomas Preudhomme wrote:
>>> Hi Richard,
>>>
>>> On Thursday 07 July 2016 16:27:27 Thomas Preudhomme wrote:
>>>> On Thursday 07 July 2016 11:52:56 Richard Earnshaw wrote:
>>>>> + As per "ARMv8-M Security Extensions: Requirements on Development
>>>>> Tools"
>>>>> + document, a secure gateway veneer is needed when there exists a
>>>>> non-local
>>>>> + function symbol called "normal" symbol (eg. foo) with the same
>>>>> value
>>>>> as a
>>>>> + symbol with the same type, binding a name save for a __acle_se_
>>>>> prefix,
>>>>> + called a "special" symbol (eg. __acle_se_foo). Entry functions
>>>>> handling + with secure state transition by themselves have these
>>>>> symbols with different
>>>>> + values.
>>>>>
>>>>>
>>>>> This is very unclear as to what is being/needs to be done. Can you
>>>>> try
>>>>> redrafting it?
>>>>
>>>> What do you think of the attached updated patch?
>>>
>>> Ping?
>>>
>>>> By the way, I realized I did not copy over the explanation for the
>>>> changes
>>>> to elf32_arm_get_plt_info from the original patch submission. I'm adding
>>>> the full cover letter again here to have all the information in one
>>>> email
>>>> in the archive.
>>>>
>>>>
>>>>
>>>> This patch is part of a patch series to add support for ARMv8-M security
>>>> extension[1] to GNU ld. This specific patch adds support for creating
>>>> ARMv8-M Secure Gateway veneers.
>>>>
>>>> ARM v8-M security extensions require [3] secure gateway veneers to be
>>>> generated for (secure) entry function in order for code to transition
>>>> from
>>>> non-secure state to secure state when calling these entry function.
>>>> Unlike
>>>> other veneers, these veneers are generated independently of relocations,
>>>> ie
>>>> a veneer can be generated in the absence of relocation. The condition
>>>> for
>>>> the generation is that the normal symbol (the one whose name is the same
>>>> as
>>>> in C) of an entry function has the same value as the special symbol
>>>> (normal
>>>> symbol prefixed with "__acle_se_"). When that happens, the normal symbol
>>>> is
>>>> rebound to the veneer generated. When the two symbols have different
>>>> value
>>>> it indicates that the entry function already contains an sg instruction
>>>> to
>>>> do the secure state transition and the normal symbol points to the sg
>>>> instruction while the special symbol points after that.
>>>>
>>>> This patch also makes use of the infrastructure laid out in previous
>>>> patches to control the address of these veneers and to avoid the
>>>> presence
>>>> of the bit pattern of the SG instruction in non secure callable memory,
>>>> as required [4] [5].
>>>>
>>>> Finally, the patch also contains a small change to
>>>> elf32_arm_get_plt_info
>>>> () to return FALSE when there is no PLT, ensuring that a NULL splt is
>>>> not
>>>> dereferenced in the block starting with "If the call goes through" in
>>>> elf32_arm_final_relocate (). This was not necessary before because
>>>> root_plt-
>>>>
>>>>> offset is set to -1 in elf32_arm_adjust_dynamic_symbol called by
>>>>
>>>> _bfd_elf_adjust_dynamic_symbol from bfd_elf_size_dynamic_sections when
>>>> dynobj is not NULL. However, dynobj is set in elf32_arm_check_relocs
>>>> which
>>>> is not called when there is no relocation in the input section. Such a
>>>> situation is possible while still invoking elf32_arm_final_relocate ()
>>>> due
>>>> to SG veneers being created in the absence of relocation but needing
>>>> themselves relocation.
>>>>
>>>> [1] Software requirements for ARMv8-M security extension are described
>>>> in
>>>> document ARM-ECM-0359818 [2]
>>>> [2] Available on http://infocenter.arm.com in Developer guides and
>>>> articles
>>>>
>>>>> Software development > ARM®v8-M Security Extensions: Requirements on
>>>>
>>>> Development Tools
>>>> [3] See section 3.4.3 and requirement 44 of ARM-ECM-0359818 [2]
>>>> [4] requirement 14 and following comment of ARM-ECM-0359818 [2]
>>>> [5] requirement 12 and 13 and following comment of ARM-ECM-0359818 [2]
>>>>
>>>>
>>>> ChangeLog entries remain unchanged:
>>>>
>>>> *** bfd/ChangeLog ***
>>>>
>>>> 2016-05-04 Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>
>>>> * elf32-arm.c (CMSE_PREFIX): Define macro.
>>>> (elf32_arm_stub_cmse_branch_thumb_only): Define stub sequence.
>>>> (cmse_branch_thumb_only): Declare stub.
>>>> (struct elf32_arm_link_hash_table): Define cmse_stub_sec field.
>>>> (elf32_arm_get_plt_info): Add globals parameter. Use it to
>>>> return
>>>> FALSE if there is no PLT.
>>>> (arm_type_of_stub): Adapt to new elf32_arm_get_plt_info
>>>> signature.
>>>> (elf32_arm_final_link_relocate): Likewise.
>>>> (elf32_arm_gc_sweep_hook): Likewise.
>>>> (elf32_arm_gc_mark_extra_sections): Mark sections holding
>>>> ARMv8-M
>>>> secure entry functions.
>>>> (arm_stub_is_thumb): Add case for
>>>> arm_stub_cmse_branch_thumb_only.
>>>> (arm_dedicated_stub_output_section_required): Change to a switch
>>>>
>>>> case and add a case for arm_stub_cmse_branch_thumb_only.
>>>>
>>>> (arm_dedicated_stub_output_section_required_alignment):
>>>> Likewise.
>>>> (arm_stub_dedicated_output_section_name): Likewise.
>>>> (arm_stub_dedicated_input_section_ptr): Likewise and remove
>>>> ATTRIBUTE_UNUSED for htab parameter.
>>>> (arm_stub_required_alignment): Likewise.
>>>> (arm_stub_sym_claimed): Likewise.
>>>> (arm_dedicated_stub_section_padding): Likewise.
>>>> (cmse_scan): New function.
>>>> (elf32_arm_size_stubs): Call cmse_scan for ARM M profile
>>>> targets.
>>>> Set stub_changed to TRUE if such veneers were created.
>>>> (elf32_arm_swap_symbol_in): Add detection code for CMSE special
>>>> symbols.
>>>>
>>>> *** include/elf/ChangeLog ***
>>>>
>>>> 2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>
>>>> * arm.h (ARM_GET_SYM_CMSE_SPCL): Define macro.
>>>> (ARM_SET_SYM_CMSE_SPCL): Likewise.
>>>>
>>>> *** ld/ChangeLog ***
>>>>
>>>> 2016-02-17 Thomas Preud'homme <thomas.preudhomme@arm.com>
>>>>
>>>> * ld.texinfo (Placement of SG veneers): New concept entry.
>>>> * testsuite/ld-arm/arm-elf.exp
>>>> (Secure gateway veneers: no .gnu.sgstubs section): New test.
>>>> (Secure gateway veneers: wrong entry functions): Likewise.
>>>> (Secure gateway veneers (ARMv8-M Baseline)): Likewise.
>>>> (Secure gateway veneers (ARMv8-M Mainline)): Likewise.
>>>> * testsuite/ld-arm/cmse-veneers.s: New file.
>>>> * testsuite/ld-arm/cmse-veneers.d: Likewise.
>>>> * testsuite/ld-arm/cmse-veneers.rd: Likewise.
>>>> * testsuite/ld-arm/cmse-veneers.sd: Likewise.
>>>> * testsuite/ld-arm/cmse-veneers-no-gnu_sgstubs.out: Likewise.
>>>> * testsuite/ld-arm/cmse-veneers-wrong-entryfct.out: Likewise.
>>>>
>>>> Best regards,
>>>>
>>>> Thomas
>>>>
>>>> sg_veneers_support.patch
>>>>
>>>>
>>>> diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
>>>> index 8de01b46671cd2ac1cbd94ef4373db439a62a9c4..b5da179d266845c6bf2aa1c9359507a2c1f0e1d1 100644
>>>> --- a/bfd/elf32-arm.c
>>>> +++ b/bfd/elf32-arm.c
>>>> @@ -2138,6 +2138,8 @@ typedef unsigned short int insn16;
>>>>
>>>> #define STUB_ENTRY_NAME "__%s_veneer"
>>>>
>>>> +#define CMSE_PREFIX "__acle_se_"
>>>> +
>>>> /* The name of the dynamic interpreter. This is put in the .interp
>>>> section. */
>>>> #define ELF_DYNAMIC_INTERPRETER "/usr/lib/ld.so.1"
>>>> @@ -2543,6 +2545,13 @@ static const insn_sequence elf32_arm_stub_long_branch_arm_nacl_pic[] =
>>>> DATA_WORD (0, R_ARM_NONE, 0), /* .word 0 */
>>>> };
>>>>
>>>> +/* Stub used for transition to secure state (aka SG veneer). */
>>>> +static const insn_sequence elf32_arm_stub_cmse_branch_thumb_only[] =
>>>> +{
>>>> + THUMB32_INSN (0xe97fe97f), /* sg. */
>>>> + THUMB32_B_INSN (0xf000b800, -4), /* b.w original_branch_dest. */
>>>> +};
>>>> +
>>>>
>>>> /* Cortex-A8 erratum-workaround stubs. */
>>>>
>>>> @@ -2622,6 +2631,7 @@ static const insn_sequence elf32_arm_stub_a8_veneer_blx[] =
>>>> DEF_STUB(long_branch_v4t_thumb_tls_pic) \
>>>> DEF_STUB(long_branch_arm_nacl) \
>>>> DEF_STUB(long_branch_arm_nacl_pic) \
>>>> + DEF_STUB(cmse_branch_thumb_only) \
>>>> DEF_STUB(a8_veneer_b_cond) \
>>>> DEF_STUB(a8_veneer_b) \
>>>> DEF_STUB(a8_veneer_bl) \
>>>> @@ -3172,6 +3182,9 @@ struct elf32_arm_link_hash_table
>>>> information on stub grouping. */
>>>> struct map_stub *stub_group;
>>>>
>>>> + /* Input stub section holding secure gateway veneers. */
>>>> + asection *cmse_stub_sec;
>>>> +
>>>> /* Number of elements in stub_group. */
>>>> unsigned int top_id;
>>>>
>>>> @@ -3320,12 +3333,16 @@ elf32_arm_create_local_iplt (bfd *abfd, unsigned long r_symndx)
>>>> union and *ARM_PLT at the ARM-specific information. */
>>>>
>>>> static bfd_boolean
>>>> -elf32_arm_get_plt_info (bfd *abfd, struct elf32_arm_link_hash_entry *h,
>>>> +elf32_arm_get_plt_info (bfd *abfd, struct elf32_arm_link_hash_table *globals,
>>>> + struct elf32_arm_link_hash_entry *h,
>>>> unsigned long r_symndx, union gotplt_union **root_plt,
>>>> struct arm_plt_info **arm_plt)
>>>> {
>>>> struct arm_local_iplt_info *local_iplt;
>>>>
>>>> + if (globals->root.splt == NULL && globals->root.iplt == NULL)
>>>> + return FALSE;
>>>> +
>>>> if (h != NULL)
>>>> {
>>>> *root_plt = &h->root.plt;
>>>> @@ -3786,6 +3803,7 @@ arm_stub_is_thumb (enum elf32_arm_stub_type stub_type)
>>>> case arm_stub_long_branch_v4t_thumb_arm_pic:
>>>> case arm_stub_long_branch_v4t_thumb_tls_pic:
>>>> case arm_stub_long_branch_thumb_only_pic:
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> return TRUE;
>>>> case arm_stub_none:
>>>> BFD_FAIL ();
>>>> @@ -3851,8 +3869,9 @@ arm_type_of_stub (struct bfd_link_info *info,
>>>> the address of the appropriate trampoline. */
>>>> if (r_type != R_ARM_TLS_CALL
>>>> && r_type != R_ARM_THM_TLS_CALL
>>>> - && elf32_arm_get_plt_info (input_bfd, hash, ELF32_R_SYM (rel->r_info),
>>>> - &root_plt, &arm_plt)
>>>> + && elf32_arm_get_plt_info (input_bfd, globals, hash,
>>>> + ELF32_R_SYM (rel->r_info), &root_plt,
>>>> + &arm_plt)
>>>> && root_plt->offset != (bfd_vma) -1)
>>>> {
>>>> asection *splt;
>>>> @@ -4163,7 +4182,16 @@ arm_dedicated_stub_output_section_required (enum elf32_arm_stub_type stub_type)
>>>> if (stub_type >= max_stub_type)
>>>> abort (); /* Should be unreachable. */
>>>>
>>>> - return FALSE;
>>>> + switch (stub_type)
>>>> + {
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> + return TRUE;
>>>> +
>>>> + default:
>>>> + return FALSE;
>>>> + }
>>>> +
>>>> + abort (); /* Should be unreachable. */
>>>> }
>>>>
>>>> /* Required alignment (as a power of 2) for the dedicated section holding
>>>> @@ -4177,8 +4205,19 @@ arm_dedicated_stub_output_section_required_alignment
>>>> if (stub_type >= max_stub_type)
>>>> abort (); /* Should be unreachable. */
>>>>
>>>> - BFD_ASSERT (!arm_dedicated_stub_output_section_required (stub_type));
>>>> - return 0;
>>>> + switch (stub_type)
>>>> + {
>>>> + /* Vectors of Secure Gateway veneers must be aligned on 32byte
>>>> + boundary. */
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> + return 5;
>>>> +
>>>> + default:
>>>> + BFD_ASSERT (!arm_dedicated_stub_output_section_required (stub_type));
>>>> + return 0;
>>>> + }
>>>> +
>>>> + abort (); /* Should be unreachable. */
>>>> }
>>>>
>>>> /* Name of the dedicated output section to put veneers of type STUB_TYPE, or
>>>> @@ -4190,8 +4229,17 @@ arm_dedicated_stub_output_section_name (enum elf32_arm_stub_type stub_type)
>>>> if (stub_type >= max_stub_type)
>>>> abort (); /* Should be unreachable. */
>>>>
>>>> - BFD_ASSERT (!arm_dedicated_stub_output_section_required (stub_type));
>>>> - return NULL;
>>>> + switch (stub_type)
>>>> + {
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> + return ".gnu.sgstubs";
>>>> +
>>>> + default:
>>>> + BFD_ASSERT (!arm_dedicated_stub_output_section_required (stub_type));
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + abort (); /* Should be unreachable. */
>>>> }
>>>>
>>>> /* If veneers of type STUB_TYPE should go in a dedicated output section,
>>>> @@ -4199,15 +4247,23 @@ arm_dedicated_stub_output_section_name (enum elf32_arm_stub_type stub_type)
>>>> corresponding input section. Otherwise, returns NULL. */
>>>>
>>>> static asection **
>>>> -arm_dedicated_stub_input_section_ptr
>>>> - (struct elf32_arm_link_hash_table *htab ATTRIBUTE_UNUSED,
>>>> - enum elf32_arm_stub_type stub_type)
>>>> +arm_dedicated_stub_input_section_ptr (struct elf32_arm_link_hash_table *htab,
>>>> + enum elf32_arm_stub_type stub_type)
>>>> {
>>>> if (stub_type >= max_stub_type)
>>>> abort (); /* Should be unreachable. */
>>>>
>>>> - BFD_ASSERT (!arm_dedicated_stub_output_section_required (stub_type));
>>>> - return NULL;
>>>> + switch (stub_type)
>>>> + {
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> + return &htab->cmse_stub_sec;
>>>> +
>>>> + default:
>>>> + BFD_ASSERT (!arm_dedicated_stub_output_section_required (stub_type));
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + abort (); /* Should be unreachable. */
>>>> }
>>>>
>>>> /* Find or create a stub section to contain a stub of type STUB_TYPE. SECTION
>>>> @@ -4429,6 +4485,7 @@ arm_stub_required_alignment (enum elf32_arm_stub_type stub_type)
>>>> case arm_stub_long_branch_thumb_only_pic:
>>>> case arm_stub_long_branch_any_tls_pic:
>>>> case arm_stub_long_branch_v4t_thumb_tls_pic:
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> case arm_stub_a8_veneer_blx:
>>>> return 4;
>>>>
>>>> @@ -4450,7 +4507,16 @@ arm_stub_sym_claimed (enum elf32_arm_stub_type stub_type)
>>>> if (stub_type >= max_stub_type)
>>>> abort (); /* Should be unreachable. */
>>>>
>>>> - return FALSE;
>>>> + switch (stub_type)
>>>> + {
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> + return TRUE;
>>>> +
>>>> + default:
>>>> + return FALSE;
>>>> + }
>>>> +
>>>> + abort (); /* Should be unreachable. */
>>>> }
>>>>
>>>> /* Returns the padding needed for the dedicated section used stubs of type
>>>> @@ -4462,7 +4528,16 @@ arm_dedicated_stub_section_padding (enum elf32_arm_stub_type stub_type)
>>>> if (stub_type >= max_stub_type)
>>>> abort (); /* Should be unreachable. */
>>>>
>>>> - return 0;
>>>> + switch (stub_type)
>>>> + {
>>>> + case arm_stub_cmse_branch_thumb_only:
>>>> + return 32;
>>>> +
>>>> + default:
>>>> + return 0;
>>>> + }
>>>> +
>>>> + abort (); /* Should be unreachable. */
>>>> }
>>>>
>>>> static bfd_boolean
>>>> @@ -5353,6 +5428,204 @@ elf32_arm_create_stub (struct elf32_arm_link_hash_table *htab,
>>>> return TRUE;
>>>> }
>>>>
>>>> +/* Scan symbols in INPUT_BFD to identify secure entry functions needing a
>>>> + gateway veneer to transition from non secure to secure state and create them
>>>> + accordingly.
>>>> +
>>>> + "ARMv8-M Security Extensions: Requirements on Development Tools" document
>>>> + defines the conditions that govern Secure Gateway veneer creation for a
>>>> + given symbol <SYM> as follows:
>>>> + - it has function type
>>>> + - it has non local binding
>>>> + - a symbol named __acle_se_<SYM> (called special symbol) exists with the
>>>> + same type, binding and value as <SYM> (called normal symbol).
>>>> + An entry function can handle secure state transition itself in which case
>>>> + its special symbol would have a different value from the normal symbol.
>>>> +
>>>> + OUT_ATTR gives the output attributes, SYM_HASHES the symbol index to hash
>>>> + entry mapping while HTAB gives the name to hash entry mapping.
>>>> +
>>>> + If any secure gateway veneer is created, *STUB_CHANGED is set to TRUE. The
>>>> + return value gives whether a stub failed to be allocated. */
>>>> +
>>>> +static bfd_boolean
>>>> +cmse_scan (bfd *input_bfd, struct elf32_arm_link_hash_table *htab,
>>>> + obj_attribute *out_attr, struct elf_link_hash_entry **sym_hashes,
>>>> + bfd_boolean *stub_changed)
>>>> +{
>>>> + const struct elf_backend_data *bed;
>>>> + Elf_Internal_Shdr *symtab_hdr;
>>>> + unsigned i, j, sym_count, ext_start;
>>>> + Elf_Internal_Sym *cmse_sym, *local_syms;
>>>> + struct elf32_arm_link_hash_entry *hash, *cmse_hash = NULL;
>>>> + enum arm_st_branch_type branch_type;
>>>> + char *sym_name, *lsym_name;
>>>> + bfd_vma sym_value;
>>>> + asection *section;
>>>> + bfd_boolean is_v8m, new_stub, created_stub, cmse_invalid, ret = TRUE;
>>>> +
>>>> + bed = get_elf_backend_data (input_bfd);
>>>> + symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
>>>> + sym_count = symtab_hdr->sh_size / bed->s->sizeof_sym;
>>>> + ext_start = symtab_hdr->sh_info;
>>>> + is_v8m = (out_attr[Tag_CPU_arch].i >= TAG_CPU_ARCH_V8M_BASE
>>>> + && out_attr[Tag_CPU_arch_profile].i == 'M');
>>>> +
>>>> + local_syms = (Elf_Internal_Sym *) symtab_hdr->contents;
>>>> + if (local_syms == NULL)
>>>> + local_syms = bfd_elf_get_elf_syms (input_bfd, symtab_hdr,
>>>> + symtab_hdr->sh_info, 0, NULL, NULL,
>>>> + NULL);
>>>> + if (symtab_hdr->sh_info && local_syms == NULL)
>>>> + return FALSE;
>>>> +
>>>> + /* Scan symbols. */
>>>> + for (i = 0; i < sym_count; i++)
>>>> + {
>>>> + cmse_invalid = FALSE;
>>>> +
>>>> + if (i < ext_start)
>>>> + {
>>>> + cmse_sym = &local_syms[i];
>>>> + /* Not a special symbol. */
>>>> + if (!ARM_GET_SYM_CMSE_SPCL (cmse_sym->st_target_internal))
>>>> + continue;
>>>> + sym_name = bfd_elf_string_from_elf_section (input_bfd,
>>>> + symtab_hdr->sh_link,
>>>> + cmse_sym->st_name);
>>>> + /* Special symbol with local binding. */
>>>> + cmse_invalid = TRUE;
>>>> + }
>>>> + else
>>>> + {
>>>> + cmse_hash = elf32_arm_hash_entry (sym_hashes[i - ext_start]);
>>>> + sym_name = (char *) cmse_hash->root.root.root.string;
>>>> +
>>>> + /* Not a special symbol. */
>>>> + if (!ARM_GET_SYM_CMSE_SPCL (cmse_hash->root.target_internal))
>>>> + continue;
>>>> +
>>>> + /* Special symbol has incorrect binding or type. */
>>>> + if ((cmse_hash->root.root.type != bfd_link_hash_defined
>>>> + && cmse_hash->root.root.type != bfd_link_hash_defweak)
>>>> + || cmse_hash->root.type != STT_FUNC)
>>>> + cmse_invalid = TRUE;
>>>> + }
>>>> +
>>>> + if (!is_v8m)
>>>> + {
>>>> + (*_bfd_error_handler) (_("%B: Special symbol `%s' only allowed for "
>>>> + "ARMv8-M architecture or later."),
>>>> + input_bfd, sym_name);
>>>> + is_v8m = TRUE; /* Avoid multiple warning. */
>>>> + ret = FALSE;
>>>> + }
>>>> +
>>>> + if (cmse_invalid)
>>>> + {
>>>> + (*_bfd_error_handler) (_("%B: invalid special symbol `%s'."),
>>>> + input_bfd, sym_name);
>>>> + (*_bfd_error_handler) (_("It must be a global or weak function "
>>>> + "symbol."));
>>>> + ret = FALSE;
>>>> + if (i < ext_start)
>>>> + continue;
>>>> + }
>>>> +
>>>> + sym_name += strlen (CMSE_PREFIX);
>>>> + hash = (struct elf32_arm_link_hash_entry *)
>>>> + elf_link_hash_lookup (&(htab)->root, sym_name, FALSE, FALSE, TRUE);
>>>> +
>>>> + /* No associated normal symbol or it is neither global nor weak. */
>>>> + if (!hash
>>>> + || (hash->root.root.type != bfd_link_hash_defined
>>>> + && hash->root.root.type != bfd_link_hash_defweak)
>>>> + || hash->root.type != STT_FUNC)
>>>> + {
>>>> + /* Initialize here to avoid warning about use of possibly
>>>> + uninitialized variable. */
>>>> + j = 0;
>>>> +
>>>> + if (!hash)
>>>> + {
>>>> + /* Searching for a normal symbol with local binding. */
>>>> + for (; j < ext_start; j++)
>>>> + {
>>>> + lsym_name =
>>>> + bfd_elf_string_from_elf_section (input_bfd,
>>>> + symtab_hdr->sh_link,
>>>> + local_syms[j].st_name);
>>>> + if (!strcmp (sym_name, lsym_name))
>>>> + break;
>>>> + }
>>>> + }
>>>> +
>>>> + if (hash || j < ext_start)
>>>> + {
>>>> + (*_bfd_error_handler)
>>>> + (_("%B: invalid standard symbol `%s'."), input_bfd, sym_name);
>>>> + (*_bfd_error_handler)
>>>> + (_("It must be a global or weak function symbol."));
>>>> + }
>>>> + else
>>>> + (*_bfd_error_handler)
>>>> + (_("%B: absent standard symbol `%s'."), input_bfd, sym_name);
>>>> + ret = FALSE;
>>>> + if (!hash)
>>>> + continue;
>>>> + }
>>>> +
>>>> + sym_value = hash->root.root.u.def.value;
>>>> + section = hash->root.root.u.def.section;
>>>> +
>>>> + if (cmse_hash->root.root.u.def.section != section)
>>>> + {
>>>> + (*_bfd_error_handler)
>>>> + (_("%B: `%s' and its special symbol are in different sections."),
>>>> + input_bfd, sym_name);
>>>> + ret = FALSE;
>>>> + }
>>>> + if (cmse_hash->root.root.u.def.value != sym_value)
>>>> + continue; /* Ignore: could be an entry function starting with SG. */
>>>> +
>>>> + /* If this section is a link-once section that will be discarded, then
>>>> + don't create any stubs. */
>>>> + if (section->output_section == NULL)
>>>> + {
>>>> + (*_bfd_error_handler)
>>>> + (_("%B: entry function `%s' not output."), input_bfd, sym_name);
>>>> + continue;
>>>> + }
>>>> +
>>>> + if (hash->root.size == 0)
>>>> + {
>>>> + (*_bfd_error_handler)
>>>> + (_("%B: entry function `%s' is empty."), input_bfd, sym_name);
>>>> + ret = FALSE;
>>>> + }
>>>> +
>>>> + if (!ret)
>>>> + continue;
>>>> + branch_type = ARM_GET_SYM_BRANCH_TYPE (hash->root.target_internal);
>>>> + created_stub
>>>> + = elf32_arm_create_stub (htab, arm_stub_cmse_branch_thumb_only,
>>>> + NULL, NULL, section, hash, sym_name,
>>>> + sym_value, branch_type, &new_stub);
>>>> +
>>>> + if (!created_stub)
>>>> + ret = FALSE;
>>>> + else
>>>> + {
>>>> + BFD_ASSERT (new_stub);
>>>> + *stub_changed = TRUE;
>>>> + }
>>>> + }
>>>> +
>>>> + if (!symtab_hdr->contents)
>>>> + free (local_syms);
>>>> + return ret;
>>>> +}
>>>> +
>>>> /* Determine and set the size of the stub section for a final link.
>>>>
>>>> The basic idea here is to examine all the relocations looking for
>>>> @@ -5369,8 +5642,9 @@ elf32_arm_size_stubs (bfd *output_bfd,
>>>> unsigned int),
>>>> void (*layout_sections_again) (void))
>>>> {
>>>> + obj_attribute *out_attr;
>>>> bfd_size_type stub_group_size;
>>>> - bfd_boolean stubs_always_after_branch;
>>>> + bfd_boolean m_profile, stubs_always_after_branch, first_veneer_scan = TRUE;
>>>> struct elf32_arm_link_hash_table *htab = elf32_arm_hash_table (info);
>>>> struct a8_erratum_fix *a8_fixes = NULL;
>>>> unsigned int num_a8_fixes = 0, a8_fix_table_size = 10;
>>>> @@ -5399,6 +5673,8 @@ elf32_arm_size_stubs (bfd *output_bfd,
>>>> htab->layout_sections_again = layout_sections_again;
>>>> stubs_always_after_branch = group_size < 0;
>>>>
>>>> + out_attr = elf_known_obj_attributes_proc (output_bfd);
>>>> + m_profile = out_attr[Tag_CPU_arch_profile].i == 'M';
>>>> /* The Cortex-A8 erratum fix depends on stubs not being in the same 4K page
>>>> as the first half of a 32-bit branch straddling two 4K pages. This is a
>>>> crude way of enforcing that. */
>>>> @@ -5464,6 +5740,18 @@ elf32_arm_size_stubs (bfd *output_bfd,
>>>> if (symtab_hdr->sh_info == 0)
>>>> continue;
>>>>
>>>> + /* Limit scan of symbols to object file whose profile is
>>>> + Microcontroller to not hinder performance in the general case. */
>>>> + if (m_profile && first_veneer_scan)
>>>> + {
>>>> + struct elf_link_hash_entry **sym_hashes;
>>>> +
>>>> + sym_hashes = elf_sym_hashes (input_bfd);
>>>> + if (!cmse_scan (input_bfd, htab, out_attr, sym_hashes,
>>>> + &stub_changed))
>>>> + goto error_ret_free_local;
>>>> + }
>>>> +
>>>> /* Walk over each section attached to the input bfd. */
>>>> for (section = input_bfd->sections;
>>>> section != NULL;
>>>> @@ -5850,6 +6138,7 @@ elf32_arm_size_stubs (bfd *output_bfd,
>>>>
>>>> /* Ask the linker to do its stuff. */
>>>> (*htab->layout_sections_again) ();
>>>> + first_veneer_scan = FALSE;
>>>> }
>>>>
>>>> /* Add stubs for Cortex-A8 erratum fixes now. */
>>>> @@ -9191,7 +9480,8 @@ elf32_arm_final_link_relocate (reloc_howto_type * howto,
>>>> /* Find out whether the symbol has a PLT. Set ST_VALUE, BRANCH_TYPE and
>>>> VALUE appropriately for relocations that we resolve at link time. */
>>>> has_iplt_entry = FALSE;
>>>> - if (elf32_arm_get_plt_info (input_bfd, eh, r_symndx, &root_plt, &arm_plt)
>>>> + if (elf32_arm_get_plt_info (input_bfd, globals, eh, r_symndx, &root_plt,
>>>> + &arm_plt)
>>>> && root_plt->offset != (bfd_vma) -1)
>>>> {
>>>> plt_offset = root_plt->offset;
>>>> @@ -13603,7 +13893,8 @@ elf32_arm_gc_sweep_hook (bfd * abfd,
>>>> }
>>>>
>>>> if (may_need_local_target_p
>>>> - && elf32_arm_get_plt_info (abfd, eh, r_symndx, &root_plt, &arm_plt))
>>>> + && elf32_arm_get_plt_info (abfd, globals, eh, r_symndx, &root_plt,
>>>> + &arm_plt))
>>>> {
>>>> /* If PLT refcount book-keeping is wrong and too low, we'll
>>>> see a zero value (going to -1) for the root PLT reference
>>>> @@ -14071,7 +14362,11 @@ elf32_arm_check_relocs (bfd *abfd, struct bfd_link_info *info,
>>>> }
>>>>
>>>> /* Unwinding tables are not referenced directly. This pass marks them as
>>>> - required if the corresponding code section is marked. */
>>>> + required if the corresponding code section is marked. Similarly, ARMv8-M
>>>> + secure entry functions can only be referenced by SG veneers which are
>>>> + created after the GC process. They need to be marked in case they reside in
>>>> + their own section (as would be the case if code was compiled with
>>>> + -ffunction-sections). */
>>>>
>>>> static bfd_boolean
>>>> elf32_arm_gc_mark_extra_sections (struct bfd_link_info *info,
>>>> @@ -14079,10 +14374,21 @@ elf32_arm_gc_mark_extra_sections (struct bfd_link_info *info,
>>>> {
>>>> bfd *sub;
>>>> Elf_Internal_Shdr **elf_shdrp;
>>>> - bfd_boolean again;
>>>> + asection *cmse_sec;
>>>> + obj_attribute *out_attr;
>>>> + Elf_Internal_Shdr *symtab_hdr;
>>>> + unsigned i, sym_count, ext_start;
>>>> + const struct elf_backend_data *bed;
>>>> + struct elf_link_hash_entry **sym_hashes;
>>>> + struct elf32_arm_link_hash_entry *cmse_hash;
>>>> + bfd_boolean again, is_v8m, first_bfd_browse = TRUE;
>>>>
>>>> _bfd_elf_gc_mark_extra_sections (info, gc_mark_hook);
>>>>
>>>> + out_attr = elf_known_obj_attributes_proc (info->output_bfd);
>>>> + is_v8m = out_attr[Tag_CPU_arch].i >= TAG_CPU_ARCH_V8M_BASE
>>>> + && out_attr[Tag_CPU_arch_profile].i == 'M';
>>>> +
>>>> /* Marking EH data may cause additional code sections to be marked,
>>>> requiring multiple passes. */
>>>> again = TRUE;
>>>> @@ -14113,7 +14419,34 @@ elf32_arm_gc_mark_extra_sections (struct bfd_link_info *info,
>>>> return FALSE;
>>>> }
>>>> }
>>>> +
>>>> + /* Mark section holding ARMv8-M secure entry functions. We mark all
>>>> + of them so no need for a second browsing. */
>>>> + if (is_v8m && first_bfd_browse)
>>>> + {
>>>> + sym_hashes = elf_sym_hashes (sub);
>>>> + bed = get_elf_backend_data (sub);
>>>> + symtab_hdr = &elf_tdata (sub)->symtab_hdr;
>>>> + sym_count = symtab_hdr->sh_size / bed->s->sizeof_sym;
>>>> + ext_start = symtab_hdr->sh_info;
>>>> +
>>>> + /* Scan symbols. */
>>>> + for (i = ext_start; i < sym_count; i++)
>>>> + {
>>>> + cmse_hash = elf32_arm_hash_entry (sym_hashes[i - ext_start]);
>>>> +
>>>> + /* Assume it is a special symbol. If not, cmse_scan will
>>>> + warn about it and user can do something about it. */
>>>> + if (ARM_GET_SYM_CMSE_SPCL (cmse_hash->root.target_internal))
>>>> + {
>>>> + cmse_sec = cmse_hash->root.root.u.def.section;
>>>> + if (!_bfd_elf_gc_mark (info, cmse_sec, gc_mark_hook))
>>>> + return FALSE;
>>>> + }
>>>> + }
>>>> + }
>>>> }
>>>> + first_bfd_browse = FALSE;
>>>> }
>>>>
>>>> return TRUE;
>>>> @@ -17765,6 +18098,9 @@ elf32_arm_swap_symbol_in (bfd * abfd,
>>>> const void *pshn,
>>>> Elf_Internal_Sym *dst)
>>>> {
>>>> + Elf_Internal_Shdr *symtab_hdr;
>>>> + const char *name = NULL;
>>>> +
>>>> if (!bfd_elf32_swap_symbol_in (abfd, psrc, pshn, dst))
>>>> return FALSE;
>>>> dst->st_target_internal = 0;
>>>> @@ -17793,6 +18129,13 @@ elf32_arm_swap_symbol_in (bfd * abfd,
>>>> else
>>>> ARM_SET_SYM_BRANCH_TYPE (dst->st_target_internal, ST_BRANCH_UNKNOWN);
>>>>
>>>> + /* Mark CMSE special symbols. */
>>>> + symtab_hdr = & elf_symtab_hdr (abfd);
>>>> + if (symtab_hdr->sh_size)
>>>> + name = bfd_elf_sym_name (abfd, symtab_hdr, dst, NULL);
>>>> + if (name && CONST_STRNEQ (name, CMSE_PREFIX))
>>>> + ARM_SET_SYM_CMSE_SPCL (dst->st_target_internal);
>>>> +
>>>> return TRUE;
>>>> }
>>>>
>>>> diff --git a/include/elf/arm.h b/include/elf/arm.h
>>>> index bafc03c52ee686671e847eff272ab5cc8a79398c..abad4731b335485f34a06b45d7edea475cfb321b 100644
>>>> --- a/include/elf/arm.h
>>>> +++ b/include/elf/arm.h
>>>> @@ -384,4 +384,11 @@ enum arm_st_branch_type {
>>>> | ((TYPE) & ENUM_ARM_ST_BRANCH_TYPE_BITMASK))
>>>> #endif
>>>>
>>>> +/* Get or set whether a symbol is a special symbol of an entry function of CMSE
>>>> + secure code. */
>>>> +#define ARM_GET_SYM_CMSE_SPCL(SYM_TARGET_INTERNAL) \
>>>> + (((SYM_TARGET_INTERNAL) >> 2) & 1)
>>>> +#define ARM_SET_SYM_CMSE_SPCL(SYM_TARGET_INTERNAL) \
>>>> + (SYM_TARGET_INTERNAL) |= 4
>>>> +
>>>> #endif /* _ELF_ARM_H */
>>>> diff --git a/ld/ld.texinfo b/ld/ld.texinfo
>>>> index bc16764b0554851217316c438ada863843915307..171ae6e55bc2bf2708a23e822218b8d4e53f8ee6 100644
>>>> --- a/ld/ld.texinfo
>>>> +++ b/ld/ld.texinfo
>>>> @@ -6853,6 +6853,12 @@ entries which only support 512Mb of code.
>>>> The @samp{--no-apply-dynamic-relocs} option makes AArch64 linker do not apply
>>>> link-time values for dynamic relocations.
>>>>
>>>> +@cindex Placement of SG veneers
>>>> +All SG veneers are placed in the special output section @code{.gnu.sgstubs}.
>>>> +Its start address must be set, either with the command line option
>>>> +@samp{--section-start} or in a linker script, to indicate where to place these
>>>> +veneers in memory.
>>>> +
>>>> @ifclear GENERIC
>>>> @lowersections
>>>> @end ifclear
>>>> diff --git a/ld/testsuite/ld-arm/arm-elf.exp b/ld/testsuite/ld-arm/arm-elf.exp
>>>> index db25a8d46c985f89e02ce68c8897923c23101661..84301626fb6ab24a6726315e810249b4375b5fdc 100644
>>>> --- a/ld/testsuite/ld-arm/arm-elf.exp
>>>> +++ b/ld/testsuite/ld-arm/arm-elf.exp
>>>> @@ -633,6 +633,33 @@ set armeabitests_nonacl {
>>>> {{objdump -d jump-reloc-veneers-long.d}}
>>>> "jump-reloc-veneers-long"}
>>>>
>>>> + {"Secure gateway veneers: no .gnu.sgstubs section" "" ""
>>>> + "-march=armv8-m.base -mthumb"
>>>> + {cmse-veneers.s}
>>>> + {{ld cmse-veneers-no-gnu_sgstubs.out}}
>>>> + "cmse-veneers-no-gnu_sgstubs"}
>>>> + {"Secure gateway veneers: wrong entry functions" "" ""
>>>> + "-march=armv7-m -mthumb --defsym CHECK_ERRORS=1"
>>>> + {cmse-veneers.s}
>>>> + {{ld cmse-veneers-wrong-entryfct.out}}
>>>> + "cmse-veneers-wrong-entryfct"}
>>>> + {"Secure gateway veneers (ARMv8-M Baseline)"
>>>> + "-Ttext=0x8000 --section-start .gnu.sgstubs=0x20000 --gc-sections" ""
>>>> + "-march=armv8-m.base -mthumb"
>>>> + {cmse-veneers.s}
>>>> + {{objdump {-d -j .gnu.sgstubs} cmse-veneers.d}
>>>> + {objdump {-h -j .gnu.sgstubs} cmse-veneers.sd}
>>>> + {nm {} cmse-veneers.rd}}
>>>> + "cmse-veneers-baseline"}
>>>> + {"Secure gateway veneers (ARMv8-M Mainline)"
>>>> + "-Ttext=0x8000 --section-start .gnu.sgstubs=0x20000 --gc-sections" ""
>>>> + "-march=armv8-m.main -mthumb"
>>>> + {cmse-veneers.s}
>>>> + {{objdump {-d -j .gnu.sgstubs} cmse-veneers.d}
>>>> + {objdump {-h -j .gnu.sgstubs} cmse-veneers.sd}
>>>> + {nm {} cmse-veneers.rd}}
>>>> + "cmse-veneers-mainline"}
>>>> +
>>>> {"R_ARM_THM_JUMP19 Relocation veneers: Short"
>>>> "--section-start destsect=0x000108002 --section-start .text=0x8000" ""
>>>> "-march=armv7-m -mthumb"
>>>> diff --git a/ld/testsuite/ld-arm/cmse-veneers-no-gnu_sgstubs.out b/ld/testsuite/ld-arm/cmse-veneers-no-gnu_sgstubs.out
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..9d1e5ba3215ae8a29585fcf04ec1f94314670a29
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-arm/cmse-veneers-no-gnu_sgstubs.out
>>>> @@ -0,0 +1,3 @@
>>>> +.*: No address assigned to the veneers output section .gnu.sgstubs
>>>> +.*: cannot size stub section: Invalid operation
>>>> +#...
>>>> diff --git a/ld/testsuite/ld-arm/cmse-veneers-wrong-entryfct.out b/ld/testsuite/ld-arm/cmse-veneers-wrong-entryfct.out
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..fd4766ab877a4abbeb8b2c4c053ab11d3f86773c
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-arm/cmse-veneers-wrong-entryfct.out
>>>> @@ -0,0 +1,19 @@
>>>> +.*: .*: Special symbol `__acle_se_loc_entry_veneer1' only allowed for ARMv8-M architecture or later.
>>>> +.*: .*: invalid .* symbol `.*loc_entry_veneer1'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: invalid special symbol `__acle_se_loc_entry_veneer2'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: invalid special symbol `__acle_se_loc_entry_veneer4'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: invalid standard symbol `loc_entry_veneer3'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: invalid standard symbol `loc_entry_veneer5'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: absent standard symbol `fake_entry_veneer1'.
>>>> +.*: .*: invalid standard symbol `obj_entry_veneer1'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: invalid special symbol `__acle_se_obj_entry_veneer2'.
>>>> +.*: It must be a global or weak function symbol.
>>>> +.*: .*: `fake_entry_veneer2' and its special symbol are in different sections.
>>>> +.*: cannot size stub section: Invalid operation
>>>> +#...
>>>> diff --git a/ld/testsuite/ld-arm/cmse-veneers.d b/ld/testsuite/ld-arm/cmse-veneers.d
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..6a44a2b5dce9de4f5d64fe644e41f5ab9840806e
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-arm/cmse-veneers.d
>>>> @@ -0,0 +1,21 @@
>>>> +
>>>> +.*
>>>> +
>>>> +
>>>> +Disassembly of section \.gnu.sgstubs:
>>>> +
>>>> +00020000 <glob_entry_veneer2>:
>>>> + 20000: e97f e97f sg
>>>> + 20004: f7e8 b800 b\.w 8008 <__acle_se_glob_entry_veneer2>
>>>> +
>>>> +00020008 <weak_entry_veneer2>:
>>>> + 20008: e97f e97f sg
>>>> + 2000c: f7e7 bffe b\.w 800c <__acle_se_weak_entry_veneer2>
>>>> +
>>>> +00020010 <glob_entry_veneer1>:
>>>> + 20010: e97f e97f sg
>>>> + 20014: f7e7 bff4 b\.w 8000 <__acle_se_glob_entry_veneer1>
>>>> +
>>>> +00020018 <weak_entry_veneer1>:
>>>> + 20018: e97f e97f sg
>>>> + 2001c: f7e7 bff2 b\.w 8004 <__acle_se_weak_entry_veneer1>
>>>> diff --git a/ld/testsuite/ld-arm/cmse-veneers.rd b/ld/testsuite/ld-arm/cmse-veneers.rd
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..20fad961bd8803109c3cf57ef22e3b36da5b1500
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-arm/cmse-veneers.rd
>>>> @@ -0,0 +1,9 @@
>>>> +#...
>>>> +[0-9a-f]+ T glob_entry_fct
>>>> +#...
>>>> +[0-9a-f]+ T glob_entry_veneer1
>>>> +[0-9a-f]+ T glob_entry_veneer2
>>>> +#...
>>>> +[0-9a-f]+ W weak_entry_veneer1
>>>> +[0-9a-f]+ W weak_entry_veneer2
>>>> +#...
>>>> diff --git a/ld/testsuite/ld-arm/cmse-veneers.s b/ld/testsuite/ld-arm/cmse-veneers.s
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..d5c57f646a78c4736e4f084d8ad6aff7efea554f
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-arm/cmse-veneers.s
>>>> @@ -0,0 +1,97 @@
>>>> + .syntax unified
>>>> + .thumb
>>>> + .file "foo.c"
>>>> + .text
>>>> +
>>>> +.macro decltype name, type
>>>> +.ifc \type,object
>>>> + .data
>>>> +.else
>>>> + .thumb
>>>> + .thumb_func
>>>> +.endif
>>>> + .type \name, %\type
>>>> +.endm
>>>> +
>>>> +
>>>> +.macro entry name, type, vis, typespc, visspc, entry_fct
>>>> + .align 2
>>>> +.ifb \visspc
>>>> + .\vis __acle_se_\name
>>>> +.else
>>>> + .\visspc __acle_se_\name
>>>> +.endif
>>>> + .\vis \name
>>>> + .thumb
>>>> + .thumb_func
>>>> +.ifb \typespc
>>>> + decltype __acle_se_\name, \type
>>>> +.else
>>>> + decltype __acle_se_\name, \typespc
>>>> +.endif
>>>> + decltype \name, \type
>>>> +__acle_se_\name:
>>>> + \entry_fct
>>>> +\name:
>>>> +.ifc \type,object
>>>> + .word 42
>>>> +.else
>>>> + nop
>>>> +.endif
>>>> + .size \name, .-\name
>>>> + .size __acle_se_\name, .-__acle_se_\name
>>>> +.endm
>>>> +
>>>> +
>>>> +.ifndef CHECK_ERRORS
>>>> + @ Valid setups for veneer generation
>>>> + entry glob_entry_veneer1, function, global
>>>> + entry weak_entry_veneer1, function, weak
>>>> + entry glob_entry_veneer2, function, global, visspc=weak
>>>> + entry weak_entry_veneer2, function, weak, visspc=global
>>>> +
>>>> + @ Valid setup for entry function without SG veneer
>>>> + entry glob_entry_fct, function, global, entry_fct=nop
>>>> +
>>>> +.else
>>>> + @ Invalid setups for veneer generation (visibility)
>>>> + entry loc_entry_veneer1, function, local
>>>> + entry loc_entry_veneer2, function, global, visspc=local
>>>> + entry loc_entry_veneer3, function, local, visspc=global
>>>> + entry loc_entry_veneer4, function, weak, visspc=local
>>>> + entry loc_entry_veneer5, function, local, visspc=weak
>>>> +
>>>> + @ Invalid setups for veneer generation (absent standard symbol)
>>>> + .align 2
>>>> + .global __acle_se_fake_entry_veneer1
>>>> + .thumb
>>>> + .thumb_func
>>>> + .type __acle_se_fake_entry_veneer1, %function
>>>> +__acle_se_fake_entry_veneer1:
>>>> + nop
>>>> + .size __acle_se_fake_entry_veneer1, .-__acle_se_fake_entry_veneer1
>>>> +
>>>> + @ Invalid setups for veneer generation (type)
>>>> + entry obj_entry_veneer1, object, global, typespc=function
>>>> + entry obj_entry_veneer2, function, global, typespc=object
>>>> +
>>>> + @ Invalid setup for veneer generation (sections)
>>>> + .section .text.sub1
>>>> + .align 2
>>>> + .thumb
>>>> + .thumb_func
>>>> + .global __acle_se_fake_entry_veneer2
>>>> + .type __acle_se_fake_entry_veneer2, %function
>>>> +__acle_se_fake_entry_veneer2:
>>>> + nop
>>>> + .size __acle_se_fake_entry_veneer2, .-__acle_se_fake_entry_veneer2
>>>> + .section .text.sub2
>>>> + .align 2
>>>> + .thumb
>>>> + .thumb_func
>>>> + .global fake_entry_veneer2
>>>> + .type fake_entry_veneer2, %function
>>>> +fake_entry_veneer2:
>>>> + nop
>>>> + .size fake_entry_veneer2, .-fake_entry_veneer2
>>>> +.endif
>>>> diff --git a/ld/testsuite/ld-arm/cmse-veneers.sd b/ld/testsuite/ld-arm/cmse-veneers.sd
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..99bfc8f37c25b7a57122b330b1145e27a9b087fd
>>>> --- /dev/null
>>>> +++ b/ld/testsuite/ld-arm/cmse-veneers.sd
>>>> @@ -0,0 +1,7 @@
>>>> +
>>>> +.*
>>>> +
>>>> +Sections:
>>>> +Idx Name Size VMA LMA File off Algn
>>>> + \d+ \.gnu\.sgstubs 00000020 00020000 00020000 00010000 2\*\*5
>>>> + CONTENTS, ALLOC, LOAD, READONLY, CODE