On 5/20/2021 6:44 AM, Feifei Wang wrote:
> Hi, Ferruh
>
> Thanks for your comments.
> Please see below.
>
>> -----邮件原件-----
>> 发件人: Ferruh Yigit <ferruh.yi...@intel.com>
>> 发送时间: 2021年5月19日 16:12
>> 收件人: Feifei Wang <feifei.wa...@arm.com>; John Griffin
>> <john.grif...@intel.com>; Fiona Trahe <fiona.tr...@intel.com>; Deepak
>> Kumar Jain <deepak.k.j...@intel.com>; Jerin Jacob
>> <jerin.ja...@caviumnetworks.com>; Herbert Guan
>> <herbert.g...@arm.com>
>> 抄送: dev@dpdk.org; david.march...@redhat.com; nd <n...@arm.com>;
>> sta...@dpdk.org; Ruifeng Wang <ruifeng.w...@arm.com>
>> 主题: Re: [dpdk-stable] [PATCH v3] crypto/qat: fix uninitilized compiler
>> warning
>>
>> On 5/17/2021 10:07 AM, Feifei Wang wrote:
>>> In Arm platform, when "RTE_ARCH_ARM64_MEMCPY" is set as true,
>> compiler
>>> will report variable uninitilized warning:
>>>
>>> ../drivers/crypto/qat/qat_sym_session.c:
>>> In function ‘partial_hash_compute’:
>>> ../lib/eal/include/generic/rte_byteorder.h:241:24: warning:
>>> ‘<U35a0>’ may be used uninitialized in this function
>>> [-Wmaybe-uninitialized]
>>> 241 | #define rte_bswap32(x) __builtin_bswap32(x)
>>> ...
>>>
>>> This is because "digest" will be initialized by "rte_memcpy" function
>>> rather than "memcpy" if "RTE_ARCH_ARM64_MEMCPY" is set as true.
>>> However,
>>
>> How 'digest' is initialized by 'rte_memcpy'?
>
> Firstly, 'digest' is initialized by rte_memcpy in partial_hash_sha_x function
> :
> 'partial_hash_compute' -> 'partial_hash_sha_x' -> 'rte_memcpy'.
>
> If "RTE_ARCH_ARM64_MEMCPY = false", rte_memcpy will be defined as
> 'memcpy' to initialize 'digest' in lib\eal\arm\include\rte_memcpy_64.h: 364,
> and compiler can identify this.
>
> However, if "RTE_ARCH_ARM64_MEMCPY = true", rte_memcpy will be a inline
> function, and finally it will initialize 'digest' with two steps by invoking
> rte_mov16:
> rte_memcpy -> rte_memcpy_ge16_lt_128 ->
> step 1: rte_mov16(dst,src )
> step 2: rte_mov16(dst - 16 + n, src - 16 + n)
> And the compiler cannot identify this multi-step initialization, then it will
> report warning.
>
OK, I got what you mean, thanks for clarification.
>>
>>> compiler cannot know it is initialized by the function.
>>>
>>> To fix this, use "calloc" to initialize "digest".
>>>
>>> Fixes: cd7fc8a84b48 ("eal/arm64: optimize memcpy")
>>> Cc: sta...@dpdk.org
>>>
>>> Signed-off-by: Feifei Wang <feifei.wa...@arm.com>
>>> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
>>> ---
>>> v2: add check and free for memory dynamic allocation (David Marchand)
>>> v3: fix compiler error
>>>
>>> drivers/crypto/qat/qat_sym_session.c | 27 ++++++++++++++++++---------
>>> 1 file changed, 18 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/crypto/qat/qat_sym_session.c
>>> b/drivers/crypto/qat/qat_sym_session.c
>>> index 231b1640da..105a10957a 100644
>>> --- a/drivers/crypto/qat/qat_sym_session.c
>>> +++ b/drivers/crypto/qat/qat_sym_session.c
>>> @@ -1190,8 +1190,7 @@ static int partial_hash_compute(enum
>> icp_qat_hw_auth_algo hash_alg,
>>> uint8_t *data_out)
>>> {
>>> int digest_size;
>>> - uint8_t digest[qat_hash_get_digest_size(
>>> - ICP_QAT_HW_AUTH_ALGO_DELIMITER)];
>>> + uint8_t *digest;
>>
>> Will a memset 'digest' work too? Although not sure which one is better.
> Thanks for your meaningful comments, I try to use memset and it is ok to
> solve this warning.
> I will update this in the next version.
>
