On 12/20/18 4:38 PM, Sam Tebbs wrote:
> On 11/22/18 4:54 PM, Sam Tebbs wrote:
>> On 11/12/18 6:24 PM, Sudakshina Das wrote:
>>> Hi Sam
>>>
>>> On 02/11/18 17:31, Sam Tebbs wrote:
>>>> Hi all,
>>>>
>>>> The -mbranch-protection option combines the functionality of
>>>> -msign-return-address and the BTI features new in Armv8.5 to better reflect
>>>> their relationship. This new option therefore supersedes and deprecates the
>>>> existing -msign-return-address option.
>>>>
>>>> -mbranch-protection=[none|standard|<types>] - Turns on different types of
>>>> branch
>>>> protection available where:
>>>>
>>>> * "none": Turn of all types of branch protection
>>>> * "standard" : Turns on all the types of protection to their
>>>> respective
>>>> standard levels.
>>>> * <types> can be "+" separated protection types:
>>>>
>>>> * "bti" : Branch Target Identification Mechanism.
>>>> * "pac-ret{+leaf+b-key}": Return Address Signing. The default return
>>>> address signing is enabled by signing functions that save the return
>>>> address to memory (non-leaf functions will practically always do this)
>>>> using the a-key. The optional tuning arguments allow the user to
>>>> extend the scope of return address signing to include leaf functions
>>>> and to change the key to b-key. The tuning arguments must proceed the
>>>> protection type "pac-ret".
>>>>
>>>> Thus -mbranch-protection=standard -> -mbranch-protection=bti+pac-ret.
>>>>
>>>> Its mapping to -msign-return-address is as follows:
>>>>
>>>> * -mbranch-protection=none -> -msign-return-address=none
>>>> * -mbranch-protection=standard -> -msign-return-address=leaf
>>>> * -mbranch-protection=pac-ret -> -msign-return-address=non-leaf
>>>> * -mbranch-protection=pac-ret+leaf -> -msign-return-address=all
>>>>
>>>> This patch implements the option's skeleton and the "none", "standard" and
>>>> "pac-ret" types (along with its "leaf" subtype).
>>>>
>>>> The previous patch in this series is here:
>>>> https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00103.html
>>>>
>>>> Bootstrapped successfully and tested on aarch64-none-elf with no
>>>> regressions.
>>>>
>>>> OK for trunk?
>>>>
>>> Thank for doing this. I am not a maintainer so you will need a
>>> maintainer's approval. Only nit, that I would add is that it would
>>> be good to have more test coverage, specially for the new parsing
>>> functions that have been added and the errors that are added.
>>>
>>> Example checking a few valid and invalid combinations of the options
>>> like:
>>> -mbranch-protection=pac-ret -mbranch-protection=none //disables
>>> everything
>>> -mbranch-protection=leaf //errors out
>>> -mbranch-protection=none+pac-ret //errors out
>>> ... etc
>>> Also instead of removing all the old deprecated options, you can keep
>>> one (or a copy of one) to check for the deprecated warning.
>> Hi Sudi,
>>
>> Thanks for the feedback, I've incorporated your suggestions into the
>> attached patch and the updated changelog.
>>
>> gcc/ChangeLog:
>>
>> 2018-11-22 Sam Tebbs<sam.te...@arm.com>
>>
>> * config/aarch64/aarch64.c (BRANCH_PROTEC_STR_MAX,
>> aarch64_parse_branch_protection,
>> struct aarch64_branch_protec_type,
>> aarch64_handle_no_branch_protection,
>> aarch64_handle_standard_branch_protection,
>> aarch64_validate_mbranch_protection,
>> aarch64_handle_pac_ret_protection,
>> aarch64_handle_attr_branch_protection,
>> accepted_branch_protection_string,
>> aarch64_pac_ret_subtypes,
>> aarch64_branch_protec_types,
>> aarch64_handle_pac_ret_leaf): Define.
>> (aarch64_override_options_after_change_1): Add check for
>> accepted_branch_protection_string.
>> (aarch64_override_options): Add check for
>> accepted_branch_protection_string.
>> (aarch64_option_save): Save accepted_branch_protection_string.
>> (aarch64_option_restore): Save
>> accepted_branch_protection_string.
>> * config/aarch64/aarch64.c (aarch64_attributes): Add branch-protection.
>> * config/aarch64/aarch64.opt: Add mbranch-protection. Deprecate
>> msign-return-address.
>> * doc/invoke.texi: Add mbranch-protection.
>>
>> gcc/testsuite/ChangeLog:
>>
>> 2018-11-22 Sam Tebbs<sam.te...@arm.com>
>>
>> * (gcc.target/aarch64/return_address_sign_1.c,
>> gcc.target/aarch64/return_address_sign_2.c,
>> gcc.target/aarch64/return_address_sign_3.c (__attribute__)): Change
>> option to -mbranch-protection.
>> * gcc.target/aarch64/(branch-protection-option.c,
>> branch-protection-option-2.c, branch-protection-attr.c,
>> branch-protection-attr-2.c): New file.
> Hi all,
>
> Attached is an updated patch with branch_protec_type renamed to
> branch_protect_type, some unneeded ATTRIBUTE_USED removed and an added
> use of ARRAY_SIZE.
>
> Below is the updated changelog.
>
> OK for trunk? I have committed the preceding patch in the series.
>
> gcc/ChangeLog:
>
> 2018-12-20 Sam Tebbs<sam.te...@arm.com>
>
> * config/aarch64/aarch64.c (BRANCH_PROTECT_STR_MAX,
> aarch64_parse_branch_protection,
> struct aarch64_branch_protect_type,
> aarch64_handle_no_branch_protection,
> aarch64_handle_standard_branch_protection,
> aarch64_validate_mbranch_protection,
> aarch64_handle_pac_ret_protection,
> aarch64_handle_attr_branch_protection,
> accepted_branch_protection_string,
> aarch64_pac_ret_subtypes,
> aarch64_branch_protect_types,
> aarch64_handle_pac_ret_leaf): Define.
> (aarch64_override_options_after_change_1): Add check for
> accepted_branch_protection_string.
> (aarch64_override_options): Add check for
> accepted_branch_protection_string.
> (aarch64_option_save): Save accepted_branch_protection_string.
> (aarch64_option_restore): Save
> accepted_branch_protection_string.
> * config/aarch64/aarch64.c (aarch64_attributes): Add branch-protection.
> * config/aarch64/aarch64.opt: Add mbranch-protection. Deprecate
> msign-return-address.
> * doc/invoke.texi: Add mbranch-protection.
>
> gcc/testsuite/ChangeLog:
>
> 2018-12-20 Sam Tebbs<sam.te...@arm.com>
>
> * (gcc.target/aarch64/return_address_sign_1.c,
> gcc.target/aarch64/return_address_sign_2.c,
> gcc.target/aarch64/return_address_sign_3.c (__attribute__)): Change
> option to -mbranch-protection.
> * gcc.target/aarch64/(branch-protection-option.c,
> branch-protection-option-2.c, branch-protection-attr.c,
> branch-protection-attr-2.c): New file.
>
ping
