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From: Feifei Wang <Feifei.Wang2@arm.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>,
	John Griffin <john.griffin@intel.com>,
	Fiona Trahe <fiona.trahe@intel.com>,
	Deepak Kumar Jain <deepak.k.jain@intel.com>,
	Jerin Jacob <jerin.jacob@caviumnetworks.com>,
	 Herbert Guan <Herbert.Guan@arm.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"david.marchand@redhat.com" <david.marchand@redhat.com>,
	nd <nd@arm.com>, "stable@dpdk.org" <stable@dpdk.org>,
	Ruifeng Wang <Ruifeng.Wang@arm.com>, nd <nd@arm.com>
Subject: [dpdk-dev] 回复: [dpdk-stable] [PATCH v3] crypto/qat: fix uninitilized compiler warning
Date: Thu, 20 May 2021 05:44:36 +0000
Message-ID: <DB9PR08MB692398F05DE01FD707DEAF78C82A9@DB9PR08MB6923.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <dcda981d-75c0-6628-fa7a-7291d0e59bf3@intel.com>

Hi, Ferruh

Thanks for your comments.
Please see below.

> -----邮件原件-----
> 发件人: Ferruh Yigit <ferruh.yigit@intel.com>
> 发送时间: 2021年5月19日 16:12
> 收件人: Feifei Wang <Feifei.Wang2@arm.com>; John Griffin
> <john.griffin@intel.com>; Fiona Trahe <fiona.trahe@intel.com>; Deepak
> Kumar Jain <deepak.k.jain@intel.com>; Jerin Jacob
> <jerin.jacob@caviumnetworks.com>; Herbert Guan
> <Herbert.Guan@arm.com>
> 抄送: dev@dpdk.org; david.marchand@redhat.com; nd <nd@arm.com>;
> stable@dpdk.org; Ruifeng Wang <Ruifeng.Wang@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: stable@dpdk.org
> >
> > Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@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. 

  reply	other threads:[~2021-05-20  5:44 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-14  7:41 [dpdk-dev] [PATCH] " Feifei Wang
2021-05-14  7:49 ` [dpdk-dev] [dpdk-stable] " David Marchand
2021-05-14  8:01   ` [dpdk-dev] 回复: " Feifei Wang
2021-05-14  8:13     ` [dpdk-dev] " David Marchand
2021-05-14  8:30       ` [dpdk-dev] 回复: " Feifei Wang
2021-05-17  9:07 ` [dpdk-dev] [PATCH v3] " Feifei Wang
2021-05-19  7:56   ` [dpdk-dev] [dpdk-stable] " Thomas Monjalon
2021-05-19  8:11   ` Ferruh Yigit
2021-05-20  5:44     ` Feifei Wang [this message]
2021-05-20  8:08       ` [dpdk-dev] 回复: " Ferruh Yigit
2021-05-19 13:13   ` [dpdk-dev] " Dybkowski, AdamX
2021-05-19 13:16   ` Dybkowski, AdamX
2021-05-20  5:47     ` [dpdk-dev] 回复: " Feifei Wang
2021-05-20  8:43 ` [dpdk-dev] [PATCH v4] crypto/qat: fix uninitilized gcc " Feifei Wang
2021-05-20  9:06   ` Dybkowski, AdamX
2021-05-21  2:00 ` [dpdk-dev] [PATCH v5] crypto/qat: fix uninitialized " Feifei Wang
2021-06-29 20:04   ` [dpdk-dev] [EXT] " Akhil Goyal

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