From: Ferruh Yigit <ferruh.yigit@intel.com>
Date: Thu, 2 May 2019 13:35:26 +0000 (+0100)
Subject: build: fix crash by disabling AVX512 with binutils 2.31
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=e19c6de3f2f12d0f49bdf9e787b3f43612c1df3c;p=dpdk.git

build: fix crash by disabling AVX512 with binutils 2.31

On Skylake platform, with native build, KNI kernel module crashes
because of the corrupted values passed to kernel module.

The corruption occurs because the userspace kni library works
unexpectedly. Compiler [1] is using AVX512 instructions and generated
binary is wrong [2].

It turned around gcc does its job correct, but gas is generating binary
wrong. And expected binutils 2.30, 2.31 & 2.31.1 are affected. Issue has
been fixed in binutils 2.32 with:
Commit x86: don't mistakenly scale non-8-bit displacements

AVX512 was already disabled with bintuils 2.30 [3], extending it to
2.31 & 2.31.1 too.

[1] gcc (GCC) 8.3.1 20190223 (Red Hat 8.3.1-2)

[2] gcc bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90028

[3] Bugzilla ID 97 has the details.

Bugzilla ID: 249
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---

diff --git a/config/x86/meson.build b/config/x86/meson.build
index ca4d12506a..0a7bed75e2 100644
--- a/config/x86/meson.build
+++ b/config/x86/meson.build
@@ -10,6 +10,10 @@ if not is_windows
 			message('Binutils 2.30 detected, disabling AVX512 support as workaround for bug #97')
 		endif
 	endif
+	if ldver.contains('2.31') and cc.has_argument('-mno-avx512f')
+		machine_args += '-mno-avx512f'
+		message('Binutils 2.31 detected, disabling AVX512 support as workaround for bug #249')
+	endif
 endif
 
 # we require SSE4.2 for DPDK
diff --git a/doc/guides/rel_notes/release_19_05.rst b/doc/guides/rel_notes/release_19_05.rst
index 439725c8aa..468e325395 100644
--- a/doc/guides/rel_notes/release_19_05.rst
+++ b/doc/guides/rel_notes/release_19_05.rst
@@ -368,6 +368,12 @@ Known Issues
    Also, make sure to start the actual text at the margin.
    =========================================================
 
+* **On x86 platforms, AVX512 support is disabled with binutils 2.31**
+
+  Because a defect in binutils 2.31 AVX512 support is disabled.
+  DPDK defect: https://bugs.dpdk.org/show_bug.cgi?id=249
+  GCC defect: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90028
+
 * **No software AES-XTS implementation.**
 
   There are currently no cryptodev software PMDs available which implement
diff --git a/mk/toolchain/gcc/rte.toolchain-compat.mk b/mk/toolchain/gcc/rte.toolchain-compat.mk
index df71e4a8b5..ea40a11c0c 100644
--- a/mk/toolchain/gcc/rte.toolchain-compat.mk
+++ b/mk/toolchain/gcc/rte.toolchain-compat.mk
@@ -27,7 +27,14 @@ ifneq ($(filter 2.30%,$(LD_VERSION)),)
 FORCE_DISABLE_AVX512 := y
 # print warning only once for librte_eal
 ifneq ($(filter %librte_eal,$(CURDIR)),)
-$(warning AVX512 support disabled because of ld 2.30. See Bug 97)
+$(warning AVX512 support disabled because of binutils 2.30. See Bug 97)
+endif
+endif
+ifneq ($(filter 2.31%,$(LD_VERSION)),)
+FORCE_DISABLE_AVX512 := y
+# print warning only once for librte_eal
+ifneq ($(filter %librte_eal,$(CURDIR)),)
+$(warning AVX512 support disabled because of binutils 2.31. See Bug 249)
 endif
 endif
 endif