Define _GNU_SOURCE is the base CFLAGS instead of relying on selftests to
manually #define _GNU_SOURCE, which is repetitive and error prone. E.g.
kselftest_harness.h requires _GNU_SOURCE for asprintf(), but if a selftest
includes kvm_test_harness.h after stdio.h, the include guards result in
the effective version of stdio.h consumed by kvm_test_harness.h not
defining asprintf():
In file included from x86_64/fix_hypercall_test.c:12:
In file included from include/kvm_test_harness.h:11:
../kselftest_harness.h:1169:2: error: call to undeclared function
'asprintf'; ISO C99 and later do not support implicit function declarations
[-Wimplicit-function-declaration]
1169 | asprintf(&test_name, "%s%s%s.%s", f->name,
| ^
When including the rseq selftest's "library" code, #undef _GNU_SOURCE so
that rseq.c controls whether or not it wants to build with _GNU_SOURCE.
Reported-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Acked-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/20240423190308.2883084-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Verify the following behavior holds true for writes and reads of HWCR from
host userspace:
* Attempts to set bits 3, 6, or 8 are ignored
* Bits 18 and 24 are the only bits that can be set
* Any bit that can be set can also be cleared
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://lore.kernel.org/r/20230929230246.1954854-4-jmattson@google.com
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
