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.
>
> > 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.
