On 27/10/16 10:55, Andre Vieira (lists) wrote:
> On 26/10/16 11:03, Kyrill Tkachov wrote:
>> Hi Andre,
>>
>> On 25/10/16 17:28, Andre Vieira (lists) wrote:
>>> On 25/07/16 14:23, Andre Vieira (lists) wrote:
>>>> This patch extends support for the ARMv8-M Security Extensions
>>>> 'cmse_nonsecure_entry' attribute in two ways:
>>>>
>>>> 1) Generate two labels for the function, the regular function name and
>>>> one with the function's name appended to '__acle_se_', this will trigger
>>>> the linker to create a secure gateway veneer for this entry function.
>>>> 2) Return from cmse_nonsecure_entry marked functions using bxns.
>>>>
>>>> See Section 5.4 of ARM®v8-M Security Extensions
>>>> (http://infocenter.arm.com/help/topic/com.arm.doc.ecm0359818/index.html).
>>>>
>>>>
>>>>
>>>> *** gcc/ChangeLog ***
>>>> 2016-07-25  Andre Vieira        <andre.simoesdiasvieira@arm.com>
>>>>              Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>>>
>>>>          * config/arm/arm.c (use_return_insn): Change to return with 
>>>> bxns
>>>>          when cmse_nonsecure_entry.
>>>>          (output_return_instruction): Likewise.
>>>>          (arm_output_function_prologue): Likewise.
>>>>          (thumb_pop): Likewise.
>>>>          (thumb_exit): Likewise.
>>>>          (arm_function_ok_for_sibcall): Disable sibcall for entry
>>>> functions.
>>>>          (arm_asm_declare_function_name): New.
>>>>          * config/arm/arm-protos.h (arm_asm_declare_function_name): New.
>>>>          * config/arm/elf.h (ASM_DECLARE_FUNCTION_NAME): Redefine to
>>>>          use arm_asm_declare_function_name.
>>>>
>>>> *** gcc/testsuite/ChangeLog ***
>>>> 2016-07-25  Andre Vieira        <andre.simoesdiasvieira@arm.com>
>>>>              Thomas Preud'homme  <thomas.preudhomme@arm.com>
>>>>
>>>>          * gcc.target/arm/cmse/cmse-2.c: New.
>>>>          * gcc.target/arm/cmse/cmse-4.c: New.
>>>>
>>> Hi,
>>>
>>> Rebased previous patch on top of trunk as requested. No changes to
>>> ChangeLog.
>>>
>>> Cheers,
>>> Andre
>>
>> @@ -19919,6 +19932,42 @@ output_return_instruction (rtx operand, bool
>> really_return, bool reverse,
>>    return "";
>>  }
>>  
>> +/* Output in FILE asm statements needed to declare the NAME of the
>> function
>> +   defined by its DECL node.  */
>> +
>> +void
>> +arm_asm_declare_function_name (FILE *file, const char *name, tree decl)
>> +{
>> +  size_t cmse_name_len;
>> +  char *cmse_name = 0;
>> +  char cmse_prefix[] = "__acle_se_";
>> +
>> +  if (use_cmse && lookup_attribute ("cmse_nonsecure_entry",
>> +                    DECL_ATTRIBUTES (decl)))
>> +    {
>> +      cmse_name_len = sizeof (cmse_prefix) + strlen (name);
>> +      cmse_name = XALLOCAVEC (char, cmse_name_len);
>> +      snprintf (cmse_name, cmse_name_len, "%s%s", cmse_prefix, name);
>> +      targetm.asm_out.globalize_label (file, cmse_name);
>> +    }
>> +
>>
>> I think this definitely warrants a quick comment explaining why you're
>> adding
>> __acle_se_ to the function label
>>
>>  
>>  /* Scan INSN just before assembler is output for it.
>> @@ -25247,6 +25301,12 @@ thumb2_expand_return (bool simple_return)
>>  
>>    if (!simple_return && saved_regs_mask)
>>      {
>> +      /* TODO: Verify that this path is never taken for
>> cmse_nonsecure_entry
>> +     functions or adapt code to handle according to ACLE.  This path
>> should
>> +     not be reachable for cmse_nonsecure_entry functions though we prefer
>> +     to guard it for now to ensure that future code changes do not
>> silently
>> +     change this behavior.  */
>>
>> I think you mean s/guard/assert/
>>
>>  +      gcc_assert (!IS_CMSE_ENTRY (arm_current_func_type ()));
>>        if (num_regs == 1)
>>          {
>>            rtx par = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (2));
>>
>> This is ok with those changes.
>> Thanks,
>> Kyrill
>>
> Hi,
> 
> Reworked comments. Also got rid of a redundant 'if (cmse_name)' in
> 'arm_asm_declare_function_name'. No change to ChangeLogs.
> 
> Cheers,
> Andre
> 
Hi,

Backported this to the embedded-6-branch in revision r<revision>.

Cheers,
Andre

gcc/ChangeLog.arm:
2016-12-05  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	Backport from mainline
	2016-12-02  Andre Vieira  <andre.simoesdiasvieira@arm.com>
		    Thomas Preud'homme	<thomas.preudhomme@arm.com>

	* config/arm/arm.c (use_return_insn): Change to return with  bxns
	when cmse_nonsecure_entry.
	(output_return_instruction): Likewise.
	(arm_output_function_prologue): Likewise.
	(thumb_pop): Likewise.
	(thumb_exit): Likewise.
	(thumb2_expand_return): Assert that entry functions always have simple
	returns.
	(arm_expand_epilogue): Handle entry functions.
	(arm_function_ok_for_sibcall): Disable sibcall for entry functions.
	(arm_asm_declare_function_name): New.
	* config/arm/arm-protos.h (arm_asm_declare_function_name): New.
	* config/arm/elf.h (ASM_DECLARE_FUNCTION_NAME): Redefine to
	use arm_asm_declare_function_name.

gcc/testsuite/ChangeLog.arm:
2016-12-05  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	Backport from mainline
	2016-12-02  Andre Vieira  <andre.simoesdiasvieira@arm.com>
		    Thomas Preud'homme	<thomas.preudhomme@arm.com>

	* gcc.target/arm/cmse/cmse-4.c: New.
	* gcc.target/arm/cmse/cmse-9.c: New.
	* gcc.target/arm/cmse/cmse-10.c: New.