[v2,2/2] build: fix crash by disabling AVX512 with binutils 2.31
diff mbox series

Message ID 20190416153932.21788-2-ferruh.yigit@intel.com
State Superseded, archived
Delegated to: Thomas Monjalon
Headers show
Series
  • [v2,1/2] build: fix meson binutils workaround
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Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Ferruh Yigit April 16, 2019, 3:39 p.m. UTC
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>
---
v2:
* Release notes "Known Issues" section updated
---
 config/x86/meson.build                   | 6 ++++++
 doc/guides/rel_notes/release_19_05.rst   | 6 ++++++
 mk/toolchain/gcc/rte.toolchain-compat.mk | 9 ++++++++-
 3 files changed, 20 insertions(+), 1 deletion(-)

Comments

Bruce Richardson April 16, 2019, 3:47 p.m. UTC | #1
On Tue, Apr 16, 2019 at 04:39:32PM +0100, Ferruh Yigit wrote:
> 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>
> ---
> v2:
> * Release notes "Known Issues" section updated
> ---
>  config/x86/meson.build                   | 6 ++++++
>  doc/guides/rel_notes/release_19_05.rst   | 6 ++++++
>  mk/toolchain/gcc/rte.toolchain-compat.mk | 9 ++++++++-
>  3 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/config/x86/meson.build b/config/x86/meson.build
> index 692aebe7a..9e9d5dc8c 100644
> --- a/config/x86/meson.build
> +++ b/config/x86/meson.build
> @@ -10,6 +10,12 @@ if host_machine.system() != 'windows'
>  			message('Binutils 2.30 detected, disabling AVX512 support as workaround for bug #97')
>  		endif
>  	endif
> +	if ldver.contains('2.31')
> +		if cc.has_argument('-mno-avx512f')
> +			machine_args += '-mno-avx512f'
> +			message('Binutils 2.31 detected, disabling AVX512 support as workaround for bug #249')
> +		endif
> +	endif

Is this not the same as the previous block just with a slightly different
error message? Should we merge the two, and print out both bug numbers?

If not merging, we can reduce the indentation by putting the second
cc.has_argument() condition on the same line as the previous check, i.e.
	"if ldver.contains(...) and cc.has_argument(...)"

Apart from this nit:

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Patch
diff mbox series

diff --git a/config/x86/meson.build b/config/x86/meson.build
index 692aebe7a..9e9d5dc8c 100644
--- a/config/x86/meson.build
+++ b/config/x86/meson.build
@@ -10,6 +10,12 @@  if host_machine.system() != 'windows'
 			message('Binutils 2.30 detected, disabling AVX512 support as workaround for bug #97')
 		endif
 	endif
+	if ldver.contains('2.31')
+		if cc.has_argument('-mno-avx512f')
+			machine_args += '-mno-avx512f'
+			message('Binutils 2.31 detected, disabling AVX512 support as workaround for bug #249')
+		endif
+	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 25cd61ca2..cf04b9b26 100644
--- a/doc/guides/rel_notes/release_19_05.rst
+++ b/doc/guides/rel_notes/release_19_05.rst
@@ -338,6 +338,12 @@  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 df71e4a8b..ea40a11c0 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