From: "Mattias Rönnblom" <hofors@lysator.liu.se>
To: Stephen Hemminger <stephen@networkplumber.org>, dev@dpdk.org
Cc: "Morten Brørup" <mb@smartsharesystems.com>,
"Bruce Richardson" <bruce.richardson@intel.com>,
"Konstantin Ananyev" <konstantin.v.ananyev@yandex.ru>,
"Zhihong Wang" <wangzhihong.wzh@bytedance.com>,
"Yuanhan Liu" <yliu@fridaylinux.org>,
"Xiaoyun Li" <xiaoyun.li@intel.com>
Subject: Re: [PATCH] rte_memcpy: fix off by one for size 16 and 32
Date: Sun, 3 Mar 2024 07:47:42 +0100 [thread overview]
Message-ID: <5a3e4cfb-cf24-49eb-8af3-b28dc263e6b0@lysator.liu.se> (raw)
In-Reply-To: <20240302204923.227105-1-stephen@networkplumber.org>
On 2024-03-02 21:49, Stephen Hemminger wrote:
> The rte_memcpy code would do extra instructions for size 16
> and 32 which potentially could reference past end of data.
>
> For size of 16, only single mov16 is needed.
> same for size of 32, only single mov32.
>
> Fixes: f5472703c0bd ("eal: optimize aligned memcpy on x86")
> Fixes: d35cc1fe6a7a ("eal/x86: revert select optimized memcpy at run-time")
>
> Suggested-by: Morten Brørup <mb@smartsharesystems.com>
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
> lib/eal/x86/include/rte_memcpy.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/lib/eal/x86/include/rte_memcpy.h b/lib/eal/x86/include/rte_memcpy.h
> index 72a92290e05d..00479a4bfbe6 100644
> --- a/lib/eal/x86/include/rte_memcpy.h
> +++ b/lib/eal/x86/include/rte_memcpy.h
> @@ -233,13 +233,15 @@ rte_memcpy_generic(void *dst, const void *src, size_t n)
> */
> if (n <= 32) {
> rte_mov16((uint8_t *)dst, (const uint8_t *)src);
> - rte_mov16((uint8_t *)dst - 16 + n,
> + if (n > 16)
> + rte_mov16((uint8_t *)dst - 16 + n,
> (const uint8_t *)src - 16 + n);
> return ret;
> }
> if (n <= 64) {
> rte_mov32((uint8_t *)dst, (const uint8_t *)src);
> - rte_mov32((uint8_t *)dst - 32 + n,
> + if (n > 32)
n is always > 32 here.
> + rte_mov32((uint8_t *)dst - 32 + n,
> (const uint8_t *)src - 32 + n);
> return ret;
> }
prev parent reply other threads:[~2024-03-03 6:47 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-02 20:49 Stephen Hemminger
2024-03-02 20:56 ` Stephen Hemminger
2024-03-02 22:10 ` Morten Brørup
2024-03-03 6:46 ` Mattias Rönnblom
2024-03-02 23:57 ` Morten Brørup
2024-03-03 6:47 ` Mattias Rönnblom [this message]
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