[meta-virtualization] [PATCH 1/4] xen: drop patch that upstream says is wrong

[Doug Goldstein]

On Thu, Aug 27, 2015 at 3:05 AM, Nathan Rossi <nathan at nathanrossi.com> wrote:
> On Thu, Aug 27, 2015 at 8:18 AM, Doug Goldstein <cardoe at cardoe.com> wrote:
>> On Tue, Aug 25, 2015 at 1:44 AM, Nathan Rossi <nathan at nathanrossi.com> wrote:
>>> On Tue, Aug 25, 2015 at 6:26 AM, Doug Goldstein <cardoe at cardoe.com> wrote:
>>>> Per upstream its not correct to always force -mfpmath=387 to work around
>>>> the -mno-sse flags. Instead strip out -mfpmath=sse that Yocto injects
>>>> for certain BSPs.
>>>> ---
>>>>  ...xen-x86-Fix-up-rules-when-forcing-mno-sse.patch | 28 ----------------------
>>>>  recipes-extended/xen/xen.inc                       |  5 ++++
>>>>  recipes-extended/xen/xen_4.5.0.bb                  |  1 -
>>>>  3 files changed, 5 insertions(+), 29 deletions(-)
>>>>  delete mode 100644 recipes-extended/xen/files/xen-x86-Fix-up-rules-when-forcing-mno-sse.patch
>>>>
>>>> diff --git a/recipes-extended/xen/files/xen-x86-Fix-up-rules-when-forcing-mno-sse.patch b/recipes-extended/xen/files/xen-x86-Fix-up-rules-when-forcing-mno-sse.patch
>>>> deleted file mode 100644
>>>> index 4c3e297..0000000
>>>> --- a/recipes-extended/xen/files/xen-x86-Fix-up-rules-when-forcing-mno-sse.patch
>>>> +++ /dev/null
>>>> @@ -1,28 +0,0 @@
>>>> -From: Nathan Rossi <nathan.rossi at xilinx.com>
>>>> -Subject: [PATCH] xen/x86: Fix up rules when forcing -mno-sse
>>>> -
>>>> -* When forcing -mno-sse specify -mfpmath=387 to avoid the fallback
>>>> -  warning
>>>> -
>>>> -Signed-off-by: Nathan Rossi <nathan.rossi at xilinx.com>
>>>> -Upstream-Status: Not-Submitted
>>>> ----
>>>> - xen/arch/x86/Rules.mk | 2 +-
>>>> - 1 file changed, 1 insertion(+), 1 deletion(-)
>>>> -
>>>> -diff --git a/xen/arch/x86/Rules.mk b/xen/arch/x86/Rules.mk
>>>> -index 6775cb5..03848f7 100644
>>>> ---- a/xen/arch/x86/Rules.mk
>>>> -+++ b/xen/arch/x86/Rules.mk
>>>> -@@ -42,7 +42,7 @@ x86 := y
>>>> - x86_32 := n
>>>> - x86_64 := y
>>>> -
>>>> --CFLAGS += -mno-red-zone -mno-sse -fpic
>>>> -+CFLAGS += -mno-red-zone -mno-sse -fpic -mfpmath=387
>>>> - CFLAGS += -fno-asynchronous-unwind-tables
>>>> - # -fvisibility=hidden reduces -fpic cost, if it's available
>>>> - ifneq ($(call cc-option,$(CC),-fvisibility=hidden,n),n)
>>>> ---
>>>> -2.1.1
>>>> -
>>>> diff --git a/recipes-extended/xen/xen.inc b/recipes-extended/xen/xen.inc
>>>> index 432bf4d..c7a2347 100644
>>>> --- a/recipes-extended/xen/xen.inc
>>>> +++ b/recipes-extended/xen/xen.inc
>>>> @@ -12,6 +12,11 @@ inherit autotools-brokensep gettext setuptools update-rc.d systemd
>>>>
>>>>  require xen-arch.inc
>>>>
>>>> +# Xen uses hardcodes the use of -mno-sse which conflicts -mfpmath=sse
>>>> +# The issue arises from certain Yocto machine BSPs injecting -mfpmath=sse
>>>> +# into the package's CFLAGS so we need to strip that
>>>> +TUNE_CCARGS := "${@oe_filter_out('-mfpmath=sse', '${TUNE_CCARGS}', d)}"
>>>
>>> Just curious, filtering out that flag will also affect the building of
>>> for example the target user-space tools no? is that problematic or do
>>> other SSE related flags (for those BSPs) cause the use of this fpmath
>>> setting regardless?
>>>
>>> Regards,
>>> Nathan
>>
>> Yes you are correct. The existing patch was more targeted. However
>> while the tools are built a lot of them aren't used.
>> meta-virtualization pulls in its own QEMU and firmware blobs. The
>> default in this case is -mfpmath=sse,387 so it won't really affect
>> anything. But you are probably right this patch should be dropped and
>> the existing path should be used. I'll approach this from the Xen side
>> again.
>
> Another way to handle this if there is no consensus from the Xen side
> is to setup the recipe to build different make targets separately.
> Essentially doing the runmake for the hypervisor with CFLAGS setup
> filtered and then building the other targets without modifying the
> CFLAGS.
>
> Regards,
> Nathan
>

That could work. I don't know how to do that in Yocto yet
unfortunately. I do know the targets:

make dist-xen -> compiles the hypervisor
make dist-tools -> compiles the tools (libxl, qemu, etc)
make install-xen -> depends on dist-xen and installs it to ${D}
make install-tools -> depends on dist-tools but unfortunately always
recompiles some items and installs to ${D}

Any chance you you point me in the right direction or what doc would
educate me on how to split up the make call?

--
Doug


>>
>> --
>> Doug
>>
>>
>>>
>>>> +
>>>>  PACKAGECONFIG ??= " \
>>>>      sdl \
>>>>      ${@bb.utils.contains('DISTRO_FEATURES', 'systemd', 'systemd', '', d)} \
>>>> diff --git a/recipes-extended/xen/xen_4.5.0.bb b/recipes-extended/xen/xen_4.5.0.bb
>>>> index 6c17b90..a5f03f3 100644
>>>> --- a/recipes-extended/xen/xen_4.5.0.bb
>>>> +++ b/recipes-extended/xen/xen_4.5.0.bb
>>>> @@ -2,7 +2,6 @@ require xen.inc
>>>>
>>>>  SRC_URI = " \
>>>>      http://bits.xensource.com/oss-xen/release/${PV}/xen-${PV}.tar.gz \
>>>> -    file://xen-x86-Fix-up-rules-when-forcing-mno-sse.patch \
>>>>      "
>>>>
>>>>  SRC_URI[md5sum] = "9bac43d2419d05a647064d9253bb03fa"
>>>> --
>>>> 2.1.4
>>>>
>>
>>
>>
>> --
>> Doug Goldstein



-- 
Doug Goldstein