On 6/10/26 17:03, Thomas Huth wrote:
On 10/06/2026 11.27, Chinmay Rath wrote:
On 6/8/26 19:27, Thomas Huth wrote:
On 08/06/2026 14.45, Thomas Huth wrote:
On 02/06/2026 08.48, Chinmay Rath wrote:
From: Nicholas Piggin <[email protected]>
Add some initial PMU testing.
- PMC5/6 tests
- PMAE / PMI test
- BHRB basic tests
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Chinmay Rath <[email protected]>
---
lib/powerpc/asm/processor.h | 2 +
lib/powerpc/asm/reg.h | 9 +
lib/powerpc/asm/setup.h | 1 +
lib/powerpc/setup.c | 20 ++
powerpc/Makefile.common | 3 +-
powerpc/pmu.c | 567
++++++++++++++++++++++++++++++++++++
powerpc/unittests.cfg | 3 +
7 files changed, 604 insertions(+), 1 deletion(-)
create mode 100644 powerpc/pmu.c
Hi Chinmay,
the problem with Clang on Travis [*] still seems to persist:
https://app.travis-ci.com/github/huth/kvm-unit-tests/jobs/639614142
Could you please have a look?
Thanks,
Thomas
[*] This already happened with Nicolas' last version:
https://www.spinics.net/lists/kvm/msg351218.html
I managed to get access to a ppc64 machine. The error is:
/tmp/pmu-eab466.s: Assembler messages:
/tmp/pmu-eab466.s:1649: Error: unrecognized opcode: `ldat'
clang: error: assembler command failed with exit code 1 (use -v to
see invocation)
make: *** [<builtin>: powerpc/pmu.o] Error 1
HTH,
Thomas
Hi Thomas,
Thanks for looking into this and providing the exact error message.
I was looking into this Travis CI job that you pointed to and noticed
that the clang version being used was 14.
I was wondering, would it be possible to use a newer version of clang
for the job since LDAT is a legit PPC insn,
that was introduced with Power 9, ISA version 3.0, way back a decade
in 2016 !
So I was wondering if using a newer version of clang that recognizes
the instruction would be a better approach.
I can reproduce the very same issue on a ppc64le box with Clang 22:
# clang --version
clang version 22.1.6 (Fedora 22.1.6-1.fc44)
Target: ppc64le-redhat-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Configuration file: /etc/clang/ppc64le-redhat-linux-gnu-clang.cfg
# make
clang -no-integrated-as -std=gnu99 -ffreestanding -O2 -msoft-float
-mno-altivec -I /root/kvm-unit-tests/lib -I
/root/kvm-unit-tests/lib/libfdt -I lib -Wa,-mregnames -g -MMD -MP -MF
powerpc/.pmu.d -fno-strict-aliasing -fno-common -Wall -Wwrite-strings
-Wempty-body -Wuninitialized -Wignored-qualifiers -Wno-missing-braces
-Werror -fomit-frame-pointer -fno-stack-protector
-Wno-frame-address -fno-pic -Wunused-but-set-parameter
-Wno-override-init -Wmissing-prototypes -Wstrict-prototypes
-mlittle-endian -c -o powerpc/pmu.o powerpc/pmu.c
/tmp/pmu-f0c247.s: Assembler messages:
/tmp/pmu-f0c247.s:1656: Error: unrecognized opcode: `ldat'
clang: error: assembler command failed with exit code 1 (use -v to see
invocation)
make: *** [<builtin>: powerpc/pmu.o] Error 1
Does compiling with Clang work for you? If so, which version?
Thomas
Thanks for sharing this observation Thomas. I did some digging on a
ppc64 machine and found the following :
The problem isn't with clang. Clang is able to perfectly identify LDAT
insn. This can be verified by writing a small C program using LDAT
within a similar asm volatile block and compiling with Clang. Sails smooth.
The problem is, the GNU assembler does not identify LDAT, unless
"-mpower10" flag is passed to it. Can be verified by writing a small .S
program making use of LDAT and passing to 'as', the GNU assembler binary.
In your Travis CI log, as I can check, the following config is used :
$ export CONFIG="--arch=ppc64 --endian=little --cc=clang
--cflags=-no-integrated-as"
"no-integrated-as" defers the assembling job to GNU assembler, and since
no "-mpower10" flag is passed, the compilation fails.
Using the following flag in the config instead, passes -mpower10 to GNU
assembler and gets the compilation job done :
--cflags="-no-integrated-as -Wa,-mpower10"
Thanks,
Chinmay
PS: I will be away traveling for a while, will get back to this as soon
as I am back. Thanks for understanding :)
