From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 92DE8A0588; Thu, 16 Apr 2020 01:12:44 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id DDA5A1DA4A; Thu, 16 Apr 2020 01:12:43 +0200 (CEST) Received: from mail-qt1-f193.google.com (mail-qt1-f193.google.com [209.85.160.193]) by dpdk.org (Postfix) with ESMTP id 7FED31DA00 for ; Thu, 16 Apr 2020 01:12:42 +0200 (CEST) Received: by mail-qt1-f193.google.com with SMTP id w24so14931889qts.11 for ; Wed, 15 Apr 2020 16:12:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=it9cc+BbG7VODr/SYrwJegtxT8NmzA/9G1NyVgjrrjA=; b=dIfwOcKV7uUxCLsUjJhiXAUxC73Q/g74ZnoIwUryUu5gLfsJTk2Z3GhepMnm5l9O+j 9omvtU8hSBUkutK/Gm3M1jezlaGe9o1p6cPiBb+dS4kVXY4YegeucsLxtIj5yf+/Pses u4uY8yFBwzX8ZbfBcZkeOr8PD5ugQav1Kray+cx6PaIaKyQf/Jt3CvGAVBDpMrMH8yfs /VMRy8axumc9zd0nlbZ9MPiDdBNhxm6r6DhHlyJibTE1tZXfoTXp734ot2krtX6Fbqek EJW9mervqBhb81zqRZegOH4mHHtb4EB0nrnX3CK/zT4smJsdzAHaF3O+eHgZZMdCwBmP hghA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=it9cc+BbG7VODr/SYrwJegtxT8NmzA/9G1NyVgjrrjA=; b=UuZj8LL1jhMIXouFzoRBkvnxGe3kYiaqCiBr5T9h3tNzo5lVlv/FlUmDUUlsnptf9l NhrIFczqOpoQkSJ02IKaZI/oLl0t45zKZWukFj+jvm6OB7ogI4mFpYpTAZu5GNe/i1BL +3AK3OcplJnSxq+0ENazChvRbkups7vTKin9i7FyxOz219cy1aYEPWZX6AI2zj4iJmw2 9+j098bdyLFIs9AtFUQp7FWzmNFFSYYrF9ijd4JoOfl3l8G+HSH0m2yZLpAo1OotCbnf Sw52plzH8lkS+P09hUqq6fdNRAD0jDV4Zxrb6EFDzgaAPKTjCYNn2Yiuto+cvi0n6NaO vbRQ== X-Gm-Message-State: AGi0Pub4o3iII/mpVWX7mgmp20x8c6D4bcCe3knvsOhm0bv+ZdJHuJwM 74pSbIFUwsGcFt5bZEsdK4U= X-Google-Smtp-Source: APiQypJ/y02qGuFR5h/R+BpJoKuxvcDo6aTmIf4qOfmjjx7CWP6i/c57jVSX6peQqHPJUMDuJACGpw== X-Received: by 2002:ac8:f23:: with SMTP id e32mr23747436qtk.368.1586992361653; Wed, 15 Apr 2020 16:12:41 -0700 (PDT) Received: from localhost.localdomain ([168.121.99.161]) by smtp.gmail.com with ESMTPSA id i4sm13732534qkh.27.2020.04.15.16.12.39 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 Apr 2020 16:12:41 -0700 (PDT) From: Dan Gora To: Thomas Monjalon , =?UTF-8?q?Mattias=20R=C3=B6nnblom?= Cc: David Marchand , dev@dpdk.org, Dan Gora Date: Wed, 15 Apr 2020 20:11:19 -0300 Message-Id: <20200415231119.27845-1-dg@adax.com> X-Mailer: git-send-email 2.24.1.425.g7034cd094b MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH] eal: choose initial PRNG seed source at runtime X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Instead of choosing to use getentropy() or the rdseed instruction for the random number generator entropy source using compilation flags, determine the best source at run time. This is accomplished by defining a weak symbol for getentropy(), checking that the compiler can generate the rdseed instruction even if the compilation platform does not natively support it, and checking for the availability of the rdseed instruction on the execution platform using rte_cpu_get_flag_enabled(). If neither getentropy() or rdseed is available, rte_get_timer_cycles() will be continue to be used as the entropy source. This also allows non-Mason builds to use getentropy(). Signed-off-by: Dan Gora --- config/x86/meson.build | 7 +++++++ lib/librte_eal/common/rte_random.c | 29 ++++++++++++++++++++++++----- lib/librte_eal/meson.build | 3 --- mk/rte.cpuflags.mk | 8 ++++++++ 4 files changed, 39 insertions(+), 8 deletions(-) diff --git a/config/x86/meson.build b/config/x86/meson.build index adc857ba2..214b16f2a 100644 --- a/config/x86/meson.build +++ b/config/x86/meson.build @@ -20,6 +20,13 @@ if cc.get_define('__SSE4_2__', args: machine_args) == '' machine_args += '-msse4' endif +# set -mrdseed if necessary so _rdseed32_step compiles if the +# compilation host does not support the RDSEED instruction. +if cc.get_define('__RDSEED__', args: machine_args) == '' and cc.has_argument('-mrdseed') + machine_args += '-mrdseed' + message('RDSEED not enabled by default, explicitly setting -mrdseed') +endif + base_flags = ['SSE', 'SSE2', 'SSE3','SSSE3', 'SSE4_1', 'SSE4_2'] foreach f:base_flags dpdk_conf.set('RTE_MACHINE_CPUFLAG_' + f, 1) diff --git a/lib/librte_eal/common/rte_random.c b/lib/librte_eal/common/rte_random.c index 57ec8fb2b..40f8b5aab 100644 --- a/lib/librte_eal/common/rte_random.c +++ b/lib/librte_eal/common/rte_random.c @@ -25,6 +25,8 @@ struct rte_rand_state { static struct rte_rand_state rand_states[RTE_MAX_LCORE]; +__rte_weak int getentropy(void *__buffer, size_t __length); + static uint32_t __rte_rand_lcg32(uint32_t *seed) { @@ -176,10 +178,24 @@ rte_rand_max(uint64_t upper_bound) return res; } +/* Use rte_get_timer_cycles() if the system does not have + * genentropy() or the rdseed instruction. + */ +__rte_weak int +getentropy(void *__buffer, size_t __length __rte_unused) +{ + uint64_t *ge_seed = __buffer; +#ifdef RTE_MACHINE_CPUFLAG_RDSEED + if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_RDSEED)) + return -1; +#endif + *ge_seed = rte_get_timer_cycles(); + return 0; +} + static uint64_t __rte_random_initial_seed(void) { -#ifdef RTE_LIBEAL_USE_GETENTROPY int ge_rc; uint64_t ge_seed; @@ -187,15 +203,18 @@ __rte_random_initial_seed(void) if (ge_rc == 0) return ge_seed; -#endif + #ifdef RTE_MACHINE_CPUFLAG_RDSEED unsigned int rdseed_low; unsigned int rdseed_high; /* first fallback: rdseed instruction, if available */ - if (_rdseed32_step(&rdseed_low) == 1 && - _rdseed32_step(&rdseed_high) == 1) - return (uint64_t)rdseed_low | ((uint64_t)rdseed_high << 32); + if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_RDSEED)) { + if (_rdseed32_step(&rdseed_low) == 1 && + _rdseed32_step(&rdseed_high) == 1) + return (uint64_t)rdseed_low | + ((uint64_t)rdseed_high << 32); + } #endif /* second fallback: seed using rdtsc */ return rte_get_timer_cycles(); diff --git a/lib/librte_eal/meson.build b/lib/librte_eal/meson.build index 4be5118ce..8382efbb8 100644 --- a/lib/librte_eal/meson.build +++ b/lib/librte_eal/meson.build @@ -17,9 +17,6 @@ deps += 'kvargs' if dpdk_conf.has('RTE_USE_LIBBSD') ext_deps += libbsd endif -if cc.has_function('getentropy', prefix : '#include ') - cflags += '-DRTE_LIBEAL_USE_GETENTROPY' -endif sources = common_sources + env_sources objs = common_objs + env_objs headers = common_headers + env_headers diff --git a/mk/rte.cpuflags.mk b/mk/rte.cpuflags.mk index fa8753531..fb7bf8a53 100644 --- a/mk/rte.cpuflags.mk +++ b/mk/rte.cpuflags.mk @@ -53,6 +53,14 @@ endif ifneq ($(filter $(AUTO_CPUFLAGS),__RDSEED__),) CPUFLAGS += RDSEED +else +# If the native environment doesn't define __RDSEED__, see +# if the compiler supports -mrdseed. +RDSEED_CPUFLAGS := $(shell $(CC) $(MACHINE_CFLAGS) $(WERROR_FLAGS) $(EXTRA_CFLAGS) -mrdseed -dM -E - < /dev/null) +ifneq ($(filter $(RDSEED_CPUFLAGS),__RDSEED__),) +CPUFLAGS += RDSEED +MACHINE_CFLAGS += -mrdseed +endif endif ifneq ($(filter $(AUTO_CPUFLAGS),__FSGSBASE__),) -- 2.24.1.425.g7034cd094b