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Re: [PULL 8/9] pc-bios/s390-ccw: Allow building with Clang, too
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PULL 8/9] pc-bios/s390-ccw: Allow building with Clang, too |
Date: |
Wed, 12 May 2021 16:09:25 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 |
On 5/12/21 1:53 PM, Philippe Mathieu-Daudé wrote:
> On 5/10/21 9:35 AM, Thomas Huth wrote:
>> Clang unfortunately does not support generating code for the z900
>> architecture level and starts with the z10 instead. Thus to be able
>> to support compiling with Clang, we have to check for the supported
>> compiler flags. The disadvantage is of course that the bios image
>> will only run with z10 guest CPUs upwards (which is what most people
>> use anyway), so just in case let's also emit a warning in that case
>> (we will continue to ship firmware images that have been pre-built
>> with GCC in future releases, so this should not impact normal users,
>> too).
>>
>> Message-Id: <20210502174836.838816-5-thuth@redhat.com>
>> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
>> Signed-off-by: Thomas Huth <thuth@redhat.com>
>> ---
>> configure | 9 ++++++++-
>> pc-bios/s390-ccw/Makefile | 3 ++-
>> 2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/configure b/configure
>> index 4f374b4889..5ebc937746 100755
>> --- a/configure
>> +++ b/configure
>> @@ -5417,9 +5417,16 @@ if { test "$cpu" = "i386" || test "$cpu" = "x86_64";
>> } && \
>> fi
>>
>> # Only build s390-ccw bios if we're on s390x and the compiler has
>> -march=z900
>> +# or -march=z10 (which is the lowest architecture level that Clang supports)
>> if test "$cpu" = "s390x" ; then
>> write_c_skeleton
>> - if compile_prog "-march=z900" ""; then
>> + compile_prog "-march=z900" ""
>> + has_z900=$?
>> + if [ $has_z900 = 0 ] || compile_prog "-march=z10" ""; then
>> + if [ $has_z900 != 0 ]; then
>> + echo "WARNING: Your compiler does not support the z900!"
>> + echo " The s390-ccw bios will only work with guest CPUs >=
>> z10."
>> + fi
>> roms="$roms s390-ccw"
>> # SLOF is required for building the s390-ccw firmware on s390x,
>> # since it is using the libnet code from SLOF for network booting.
>> diff --git a/pc-bios/s390-ccw/Makefile b/pc-bios/s390-ccw/Makefile
>> index 83fb1afb73..cee9d2c63b 100644
>> --- a/pc-bios/s390-ccw/Makefile
>> +++ b/pc-bios/s390-ccw/Makefile
>> @@ -34,7 +34,8 @@ QEMU_CFLAGS += $(call cc-option,-Werror
>> $(QEMU_CFLAGS),-Wno-stringop-overflow)
>> QEMU_CFLAGS += -ffreestanding -fno-delete-null-pointer-checks -fno-common
>> -fPIE
>> QEMU_CFLAGS += -fwrapv -fno-strict-aliasing -fno-asynchronous-unwind-tables
>> QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS), -fno-stack-protector)
>> -QEMU_CFLAGS += -msoft-float -march=z900
>> +QEMU_CFLAGS += -msoft-float
>> +QEMU_CFLAGS += $(call cc-option, $(QEMU_CFLAGS),-march=z900,-march=z10)
>> QEMU_CFLAGS += -std=gnu99
>> LDFLAGS += -Wl,-pie -nostdlib
>
> This broke the travis-ci "[s390x] Clang (disable-tcg)" job:
> https://travis-ci.org/github/qemu/qemu/jobs/770794417#L1776
>
> Description: Ubuntu 18.04.4 LTS
> Release: 18.04
> Codename: bionic
>
> $ clang --version
> clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
> Target: s390x-ibm-linux-gnu
Using clang-10:
C compiler for the host machine: clang-10 (clang 10.0.0-4ubuntu1 "clang
version 10.0.0-4ubuntu1~18.04.2 ")
C linker for the host machine: clang-10 ld.bfd 2.30
C++ compiler for the host machine: clang++-10 (clang 10.0.0-4ubuntu1
"clang version 10.0.0-4ubuntu1~18.04.2 ")
C++ linker for the host machine: clang++-10 ld.bfd 2.30
[...]
Compilation
host CPU: s390x
host endianness: big
C compiler: clang-10
Host C compiler: clang-10
C++ compiler: clang++-10
clang-10 -Wall -Wstrict-prototypes -Wredundant-decls -Wundef
-Wwrite-strings -Wmissing-prototypes -Wold-style-definition
-Wtype-limits -Wformat-security -Wformat-y2k -Winit-self
-Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels
-Wexpansion-to-defined -Wno-initializer-overrides
-Wno-missing-include-dirs -Wno-shift-negative-value -Wno-string-plus-int
-Wno-typedef-redefinition -Wno-tautological-type-limit-compare
-ffreestanding -fno-delete-null-pointer-checks -fno-common -fPIE -fwrapv
-fno-strict-aliasing -fno-asynchronous-unwind-tables
-fno-stack-protector -msoft-float -march=z10 -std=gnu99 -nostdinc
-I/home/travis/build/philmd/qemu/roms/SLOF/lib/libc/include
-I/home/travis/build/philmd/qemu/roms/SLOF/lib/libnet -MMD -MP -MT
jump2ipl.o -MF ./jump2ipl.d -O2 -g -c -o jump2ipl.o
/home/travis/build/philmd/qemu/pc-bios/s390-ccw/jump2ipl.c
clang: warning: argument unused during compilation: '-msoft-float'
[-Wunused-command-line-argument]
/home/travis/build/philmd/qemu/pc-bios/s390-ccw/jump2ipl.c:67:18: error:
invalid operand for instruction
asm volatile("lghi 1,1\n\t"
^
<inline asm>:1:7: note: instantiated into assembly here
lghi 1,1
^
/home/travis/build/philmd/qemu/pc-bios/s390-ccw/jump2ipl.c:67:29: error:
invalid operand for instruction
asm volatile("lghi 1,1\n\t"
^
<inline asm>:2:7: note: instantiated into assembly here
diag 1,1,0x308
^
2 errors generated.
Makefile:20: recipe for target 'jump2ipl.o' failed
make[1]: *** [jump2ipl.o] Error 1
- [PULL 3/9] pc-bios/s390-ccw: Use reset_psw pointer instead of hard-coded null pointer, (continued)
- [PULL 3/9] pc-bios/s390-ccw: Use reset_psw pointer instead of hard-coded null pointer, Thomas Huth, 2021/05/10
- [PULL 5/9] pc-bios/s390-ccw: Silence warning from Clang by marking panic() as noreturn, Thomas Huth, 2021/05/10
- [PULL 4/9] pc-bios/s390-ccw/netboot: Use "-Wl, " prefix to pass parameter to the linker, Thomas Huth, 2021/05/10
- [PULL 7/9] pc-bios/s390-ccw: Silence GCC 11 stringop-overflow warning, Thomas Huth, 2021/05/10
- [PULL 6/9] pc-bios/s390-ccw: Fix the cc-option macro in the Makefile, Thomas Huth, 2021/05/10
- [PULL 8/9] pc-bios/s390-ccw: Allow building with Clang, too, Thomas Huth, 2021/05/10
- Re: [PULL 8/9] pc-bios/s390-ccw: Allow building with Clang, too,
Philippe Mathieu-Daudé <=
[PULL 9/9] pc-bios/s390: Update the s390-ccw bios binaries with the Clang and other fixes, Thomas Huth, 2021/05/10
Re: [PULL 0/9] s390-ccw bios update, Peter Maydell, 2021/05/12